Practical Ophthalmology: A Concise Manual for the Non- ophthalmologist . need for another ophthalmology book, and concluded that one should be written . PDF | a manual of practical ophthalmology for medical students. Practical Ophthalmology - A Manual for Beginning Residents ()(1).pdf - Free ebook download as PDF File .pdf), Text File .txt) or read book online for free.
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Ophthalmology PDF Books 1-Anatomy. 5-Practical Ophthamology,A Manual for Beginning Residents 6-Wong Ophthalmology Examinations Review. Practical Ophthalmologya Manual for Beginning Residents. Reviewed by J SCOTT Full Text. The Full Text of this article is available as a PDF (68K). This book is aimed at the trainee ophthalmologist starting his first post in ophthalmology who has a steep learning curve with much new information and new.
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Add to Cart. Print this page. View Samples. Blomquist, MD Print: Customer Reviews. Only registered users can write reviews. Please Sign in or create an account. With Academy eBooks, you can: Get convenient online access to Academy eBooks from nearly any desktop or laptop computer. With advan cing age comes an increased prevalen ce of major causes of visual imp airment eg, diabet ic retinopa thy, glauco ma, cataract, and age-related macul ar de- generation.
T he op ht halm ologist-in-trainin g needs to give sp ecific co nsideratio n to the special ne eds and impac t of visual loss in aged pati ents. The wo rd "s enile," as in senile cata ract, is we ll established in med ical termin ology, but this word has unp leasant co nnotatio ns and sho uld no t be used in the presence of pa- tient s. In volutional o r age-related are far pr efer ab le if an eq uivalent adjective is nee de d.
Lo ss of visual fu nction increases the incidence and severity of falls and frac tures. Pre ven ting falls is a much mo re effective strategy th an treati ng th em.
Possible intervent io ns for reducing th e risk of fallin g include th e fo llowing:. Visu al loss an d hearing imp airment often coex ist, and th e p resen ce of both sen so ry deficits is wo rse than eithe r o ne alo ne. Op ht halm ologists sho uld reco gnize hear ing- imp air ed patients and refer them as needed fo r manageme nt. Visu al loss is also commonly associa ted wi th depression , especia lly in elderly patient s.
D ep ression sho uld not be overloo ked or ignored, as it is a deb ilitating, yet tre at ab le, co n- dition. Patient s rarel y tell th eir ophthalm ologists th at th ey are depressed, and they oft en do not reco gn ize their o w n depressio n. The o ph thalmologist may simply ask , "Do yo u feel sad or depressed? Loss of visu al cues can wo rse n sym p toms of dem enti a, and visual impa ir ment is asso ciated wi th Alzhe im er's d isease.
One such test is the" clock draw. Pati ents wh o fail th e test shou ld have evalu- ation for pos sible dementi a. Visual loss can have profound effects on many activities of daily living, such as walk - ing, going outs ide, getting in and out of bed, groc ery shopp ing, paying bills, cleaning hou se, answering th e teleph on e, cooking, and driving.
Many of these problems can be help ed by low- vision evaluation and tr eatment using optical and nonop tical rehabilita- tive aids.
One of the most simpl e, comm on, and useful aids is a high-plus reading pr e- scription th at serv es to magnify reading material. Social, family, commun ity, and other support services often improve the visually impaired patient's qual ity of life. Th e ophthalmologis t may be called upon to make reco mmendat ions to licensing agencies for candidates who do no t meet the criteria for an unr estricted dr iver's license.
Some states now require vision testing for elderl y dri vers at the time of license renewal. Altho ugh visual acuit y may be th e sole criter ion of visual function measured in many states, visual acuity alo ne is a poor pr edicto r of at-fau lt crash invo lvement.
Safe dr iving requires the motor abilit y to scan a rapidl y changing envir onm ent and to react in a timel y fashi on, the senso ry ability to perceive info rmat ion in the rapidly ch anging environment, th e atte nt iveness to process multiple pieces of information, and the cognitive ability to judge this infor mation and make appropriate decision s. Th e license to dri ve a car on public ro ads is a pri vilege rather th an a right.
Ophthalmol ogists sho uld be familiar with th e dr iving requ irement s of thei r indi vidu al sta tes. Medical Record Keeping Timely, legible, and tho rough docum ent ation of the opht halmic evaluation allows the ophthalmo logist and ot her caregivers to refer to the data in th e fut ure and thu s is of treme ndous importance to patient care and continuity of care.
Many oph thalmo logists now use an electronic com puteri zed med ical record, and advant ages of such a system include improved legibility, accessibilit y from multiple sites, and red uced space require- ments for sto rage.
Alt hou gh som e abbreviation s are widely used, ophthalmologic med- ical record s sho uld be w ritte n using term inology that will be und erstand able to other health care providers who will access the med ical recor ds. Excessive use of jargon sho uld be avoided. As a medicolegal document, the medical reco rd must pre sent sufficiently detailed findin gs and tr eatm ent reco mmen dation s. Th e record mu st be sufficient ly com- plete to justify coding levels fo r charges and reim bur sement.
C omm uni cation with referrin g physicians and other health care pro viders, w hether w ritten or verba l, is cruci al in providing the pa tient wit h continuit y and coo rdina tion of care.
Such commu nicat ion should be clear, timely, and informative. Overview of the Ophtha lm ic Evaluat ion Some ocu lar condi tion s occur as mani festations of systemic d isea ses that consti tut e a threat to p ub lic hea lth, su ch as gonococcal co njunctivi tis and oc u lar infections related to human imm unod eficiency virus.
Som e such d iseases, by sta tutory guid elin es, mus t be re- ported to th e state h eal th dep artment. State s also oft en want reports abo ut p atients w ho have rece ntly become legally blin d. Rep ort ing gu ide line s vary fro m state to state; oph - thalmolo gists sho u ld con tact th eir sta te h ealth d ep artm en t for app rop riate gu id elines. In this wa y, ke y historic poin ts or exami nat ion finding s are much less likely to be omitted.
T his reacti o n is norm al. A me rican Aca dc my of O phth alm olo gy; 20 The Profession of Ophthalm ology: Practice Mana gem ent, Ethics, and Advocacy, 2nd ed. American A cad emy of Opht ha lm o logy; 20 M iller AM. Ac ccssed May 11, 5. Movagha r M, L aw re nce M G. Ey e exam: San F ranc isco: Am eric an A cad em y of O p hth almol ogy; Rev iew ed for cur rency Am eric an Aca demy of Oph thal mo log y; Pedia tric Ophthalm ology and St rabismus.
Basic an d C linic al Science C our se, Secti on 6. Am eric an Ac adcm y of Op hth almo log y; p u b lished ann ua lly. Vision R equirements fo r D riving [Po licy Stat emen t]. Amcrica n Acade m v of O p ht ha lmology; Although si mi lar to th e gen er al med ical h istory that you learn ed in medica l sc ho o l, the op hthal mi c h istory emp hasiz es sy m p to ms of oc u lar d isease, p resent and p ast ocular problem s, an d o cula r m edi cations.
The h isto ry is intended to elicit an y in form ation t ha t mi ght be useful in eva luat in g and managing th e patient; it ma y be as br ief o r as ext ensi ve as required by th e p ati en t' s particul ar pro ble ms.
This chap ter prov ide s an overview of the op htha lm ic histo ry, its goals, recording me t ho d s, and co mponents. Goals of the History T he hi st o ry shou ld allow fo r th e re co rdi ng of impo rta nt inf or m at io n t ha t cou ld affec t the p ati ent 'Sd iagnosis and tre atment. T he 5 mos t im p ortant o bjec t ives includ e t he fo llowing:.
Ident ify the patient. If not alrea dy coll ected, reco rd d em o graphic info r mat io n about t he pa tient, su ch as nam e, add res s, d at e o f birth , se x, race, a nd med ica l reco rd number.
Identify other practitioners ,zdJ O have cared for the patient 01' ubo may carefor the patient in the f utu re. Su ch ind ivid ual s might need to be con tacted fo r ad d itiona l in formation or be given in for m ation abou t th e p ati ent, esp ecially if t he p atient wa s referred for cons ultation, in w hi ch case a writt en rep ort is req u ire d.
Reports also arc o ften ne ed ed foll o w in g referrals from attorneys, in suran ce co m p anies, o r go ve rn m ental ag enc ies , 3. Obtain a prelim inary diagnosis. Th e likely d iagnosis , or at least a reasona ble d if - fe r ent ial di agn osis, can o fte n be suspec te d m er ely o n t he basis of a good history.
T his, in tu rn , allo w s for the p lann ing an d tailo ri ng of a mo re usefu l and efficient exa mi natio n. Select therapy, K no win g and record ing t reat m en ts that have alrea dy b een tr ied , an d w he th er or not a nd in w hat way s th ey we r e help ful , is inval uab le in p lannin g t herap v for th e fu ture. A n aw k w ard situ at ion ca n ar ise if a ph y sician recommends th erap y, o nly to learn t ha t the sam e therap y has alread y been tri ed and has failed.
Insufficient knowled ge o f th e res ults of p rior th erapeutic effo rts can also lead to m isd iagn osis. T h is can be d one d ir ectl y by q uest ioning the patient o r, in man y cases, ind ircctl y by list ening att entively to,. Some patients require definitive therapy, whereas others need onl y explanati on and reassurance, documentation of a prob- lem, or periodic ob servation.
Consider socioeconomic and m edicolegal facto rs. Insurance payments, worker's compensation payments, disab ility payments, and the like on the patient's behalf , as well as legal proceedings, often depend on detailed, accurate reports or even testimony from th e ph ysician. Such reports can be inadequate and sometimes even humiliating for the ph ysician if a thorough history has not been obtained. In addition, a well-taken history can save time and expens e by ob viatin g needl ess tests and examination procedures.
Such efficiency and cost containment is impor- tant in the curr ent environment of cost -containment.
Also, the components and thoroughness of the history are considered and may be audited by payors eg, Medicare to determine the appropriateness of coding and charges for ser vices. Methods of Recording the History The preci se method of recording the history depends on the requirements of the practice or institution.
Th e history may be hand written on blank paper or on a preprinted form, dicta ted for later transcription, or entered into a computerized database. Components of the History As described below, the components of the ophthalmic history are essentia lly the same as the components of any general medical history, except that ophthalmic aspects are emphasized. Th e components of the history are the follo wing:. Chief Complaint The patient's main complaintis should be recorded in the patient's own w ords or in a nontechnical pa raphrasing of th e patient's words.
It is not advisable in this early phase of the history for the ophthalmologist to draw hast y conclusions by employing medica l terms that suggest pr emature diagnoses. Th e ph ysician 's impression is appropriate only later, after a pro p er h ist or y has been take n and a suitably thoro ug h examination has been p erfo rmed.
O f co urse, patient s are sometimes troubled by more than I sy mptom or prob lem and so might have mo re tha n 1 chief co mp laint. Pr o blems that are of lesser importance shou ld be cited alo ng with the chief complaint.
H ere arc so me examples of t he kin ds of questions that can help to elicit th e pati ent 's main complaints:. T his typ e of q uest ion so metimes reveals ent irely un founded fears , suc h as b lind ness o r cancer.
History of the Present Illness Evaluation of the p atient 's pre sent illness co nsists main ly of an effort to reco rd add itiona l inform ation and d etails abo ut the chief complaint s.
The patient's own word s may be used here w hen des ired, altho ug h the ph ysician's wo rds, includ ing med ical termino logy and abb reviatio ns, are mo re often used to rep rese nt wha t the patient said.
Information elicited abo ut the p resent illness allows the op hthalm ologist to begin develop ing a pre- liminary diagn ostic imp ression. T he fo llowin g gene ral areas of inqui ry are given as suggestions for developing infor- mati on abou t th e pr esent illness.
Was it sudde n or grad ua l? H as the pr obl em imp roved, worsened, or remained the same? What migh t have pr ecip itated the condition , made it bette r or worse , or made no difference? Ask ing about p rior therapeut ic effo rts is esp eciall y impor- tant , and it is helpful to know when the patient 's refractive p rescrip tion wa s last changed. H as the prob lem bee n inte rmitte nt or seaso nal, or d oes it worsen at a p arti cu lar time of day?
If so, were th er e an y influe nces that see med to p recip itate exacerbations or remissions? Is th e p rob lem uni later al or b ilateral? It is so metimes nece ssar y to clarify wh at th e patient mean s by cert ain complaint s. Fo r example, do es " matt ering" of th e ey e mea n sea ling of the eye lid s by sti ck y d isch arge, the mer e p resence of st rands of mucu s at ti mes , or simp ly the noting of tin y granules on the eye lids as from dried muc us o r the dr ying and cr ystallizat ion of eyed rops?
Old records, or even old photographs, can be of value in doc - umenting the presence or absence of particular problems in the past eg, ptosi s, abnormal ocular motility, proptosis, facial nerve palsy, anisocoria. Specific complaints that might be recorded under "History of the Pr esent Illness" are too numerous to list here in their entirety.
Nevertheless, one needs to keep in mind certain general categories of complaints, which are listed below together with examples of accompanying specific compla ints.
Trauma Cases of ocular tr aum a in part icular can require very detailed repo rt s based on a tho r- ough histo ry and examin ation. For mcdical, mcdicolegal, and co mpen satio n purposes, it is impo rtant to obtain the following information:. Past O cular History Prior ocu lar problems can have a bcarin g on a pa tient's statu s. You sho uld ask the pat ient about the existe nce of any such probl ems so that their po ssibl e role in th e pres cnt illness can be evaluat ed, and so that th ey can bc managed, if neccssar y.
To begin with, th e patient is usually asked simp ly if there have been any eye p rob- lems in the past, but it is often useful for elicitin g additional inform ation to ask about the following:. If the patient respon ds po sitively to any of th e above, it might be valuable to ask why, when, how, w here, and by whom, as app licable.
Ocular Medications Kno wledge of the patient 's use of ocular medications is essent ial. It is necessary to know how th e patient respo nded to prior th erapy. In addition , recent therapy can affect the patient 's present status, because toxic and allergic reaction s to topica l medic ations and p reservatives som etimes resolve slowly. All current and prior ocu lar medic ations used for th e present illness should be recorded, includ ing dosages, frequ ency, and duration of use.
Also ask about the use of any over-t he-cou nt er no nprescription medicatio ns, home remedies, herbal medicines, and dietary supplements. Patients sometimes do no t kn ow the names of their medication s. In such cases, th e physician might learn the general classes of medicati on s being used by asking the color of the cap on the container, because some containers for eyedrops have caps of different colors to facilitate ident ification:.
General Medical and Surgical History The patient 's p resent and past general medic al history is imp ortant fo r 2 reason s. First, many ocular diseases are manifestations of o r are associated with sys temic diseases.
Second, th e general medical status mu st be known to perfo rm a pr oper preop erative evaluati on. All medi cal and surg ical pr o blems sho uld be reco rded, along with the approximat e dates of onset, medica l trea tments, o r surgeries when possible.
D iabetes mellitu s shou ld be identified as insulin dependent or non-insu lin depe ndent , and th e du ratio n of dia be- tes should be determined.
T he adequacy of glycemic co ntro l is imp o rtant information to acqu ire. Previous history of and tr eatment for sexually tr ansmitted dise ases can be pertinent in cert ain situa tions. Th e evaluation of a pediatric patient might req uire obtaining historic informatio n from the mother abo ut pregnancy p renatal care, drugs used, complications in labor, prematurity, del ivery, birt h weight, and th e neo natal period. Systemic Medications System ic medicatio ns can cause ocular, pr eop erat ive, int rao perative, and postop erative problems and can provide clues to system ic disorders th e patient might have.
Part icu lar attention sho uld be given to t he use of aspirin and other ant icoag ulant agents, as they can cause int raop erative and po stoperative bleeding. Th e patient 's use of system ic medi- cation s eg, acetazo lam ide, vitamins th at are taken for ocular prob lems may be record ed here or, preferably, und er "Ocular Medications.
Certain medicines, suc h as ant imalari als, phenothi azin es, amiodaro ne, tamoxifen, and systemi c steroids, can have ocular toxicity. Patients may also be taking alternative medi- cations, herbal co mpound s, and vitami ns th at should be no ted here. Alle rgies The p atient's histor y of allergies to medication s is impo rta nt.
However, patients oft en cannot differenti ate tru e allergic reactions from side effects o r other non -allergenic adver se effects of medication s, so it is importa nt to ask abo ut and record the natu re of any claimed reac tio n. Itching, hives, rash es, w heezing, or frank cardiorespirato ry collapse clearly suggest tr ue allergy, where as statements such as " the d rop s burned " or "t he p ills upset my sto mach " do not.
In additio n to inq u iries about allergic reactions to topical and sys temic medication s, the physician sho uld ask about allergies to environmental agents atopy , resu ltin g in any of the followi ng:. In some instanc es, the pre sence of th ese kinds of disord ers might alread y have been elicited in the taking of the pr esent illness, past medical histo ry, or review of systems, in which case it need not be again recorded und er "All ergies.
Social Hist ory A social history should be tak en, including information on such matters as tobac co and alcoh ol use, drug abus e, sexual history including sexually transmitted diseases , tattoos, body-piercing, and enviro nmental factors. A det ailed occupational histo ry should be taken to include th e visual requirements of the pati ent's job and hobbies.
As man y jobs have specific visual requ irem ents eg, commercial truck driv er, law enforcement officer, pilot , this information is vital. The questioning should be pursued in a nonjudgmental way, with sensitivity and due respect for privac y. Except as might be req uired by law, or with the patient's permission, such information should not be revealed to third parti es.
Family History The family history of ocular, or nonocular, diseases is important when genetic ally trans- mitted disorders are under consideration. The physician might begin by asking a general question such as, "A re there any eye problems, other than just needing glasses, in your family history?
Knowledge of familial systemic diseases can be helpfu l in ophthalmic evaluation and diagnosis. Examples include atopy, thyroid disease, diabetes mellitus , cert ain malignan - cies, various hereditary syndromes, and many others. Inability of the patient to provide information about the famil y medical background should not be construed or recorded as a negative family history.
Rather, the chart should reflect the fact that the pati ent's knowl edge was incomplete or lacking. Exami nation of family members can be usefu l when pati ents present with possibly heritable disorders. Review of Systems A pertinent review of systems, tailored to the patient's complaints, should be conducted, including questions abou t diabetes mellitus , hypertension, and malignancy, as well as dermato logic, cardiac, renal, hepatic, pulmonary, gastrointestinal, central ner vous sys- tem, and autoimmune collag en vascular including arthritic diseases.
The history need not be of great length, but it should contain all the details that are pertinent to the patient's com- plaints and prob lems. Hist ory Taking Parent s, gua rdians, ot her relatives, o r friend s ar e som et imes need ed to give his- tories for patients w ho ar e un abl e to speak fo r themselves.
A n int erpreter can be invaluab le for an y pa tient w ho docs not spea k the ph ysician 's lan guage. A good histo r y may be brief or lengthy, as lo ng as it is thorough relat ive to th e ult imat e goa l of help ing the patient.
The ability to take an essentially complete, ye t efficient , history is an impo rt ant aspec t of the art of me d icine. N evert heless, th e begin ning op ht halm olo gy resid ent w hose histories fall short of bei ng idea l should not be d ism ayed; the skill imp ro ves grea tly with practice.
Suggest ed Resources Fundamentals and Prin ciples of Oph thalmo logy. Basic and C linical Science C our se, Section 2. A merican A cad emy of Ophthalmology; pu blishe d ann ua lly. In traocular I nfla m mation and Uveitis. Basic and Cl in ical Science Co urse , Sectio n 9. San Fr ancisco: Am erican Aca de my o f Op hthalmo log y; p ublish ed an nually. Pediatric Oph thalmology and Strabismus. Basic and C linical Science Course, Section 6. American Acad em y of O p ht halmo logy; pu blished an nually.
Vision is a complex human sense with many facets that cannot be measured. Ophthal- mologists rely on a variety of psychophysical assessments and express vision as a mea- sure of visual acuity, although acuity is only 1 component of vision. Vision consists of, but is not limited to, visual acuity, visual field, and contrast sensitivity. This chapter deals mainly with measuring distance and near visual acuity, ncar points of accommodation and convergence, and stereopsis.
Test ing Conventions and Materials The term visual acuity refers to an angular measurement relating testing distance to the minimal object size resolvable at that distance. Ophthalmologists typically use Snellen acuity as a measure of the resolving ability of the eye. The traditional Snellen measure- ment of distance acuity utilizes targets, or optotypes, that subtend a visual angle on the retina of 5 minutes of arc.
Each smaller component of the optotype, such as the individ- ual bars and spaces of the letter "E," subtcnds a visual angle of 1 minute on the retina. One minute is the smallest angle discernible for normal human vision. If the vision is tested at a distance other than 20 feet, the target size must be adjusted to maintain the correct visual angle. Larger targets are designated by a larger number in the denominator. This number represents the distance at which that target subtends a visual angle of 5 minutes.
Varieties of measurement and notation methods, test targets, and abbreviations have been developed for the purpose of performing visual acuity and visual function testing and for documenting the results. This chapter presents an overview of the standard con- ventions and steps used in performing these tests. M easurement Notation The Snellen notation is the most common method of expressing visual acuity measure- ment.
By convention, this expression is written as a fraction, but it is not a mathematical fraction or expression. The optical meaning of the fraction is described above, but a more practical way to think of it is that the number in the numerator position is the equiva- lent of the testing distance from the eye to the chart being used, in either feet or meters, while the number in the denominator position is the distance at which a subject with.
Other types of visual acuity notations are used besides th e Snell en notation. A deci- mal no ta tion co nverts th e Snell en frac tion to a de cimal; fo r example, Snellen equals de cimal 1. Other exp ressions of acui ty are the M , o r met ric, and the 10gMAR notations. The latt er exp resses visual acu ity as th e logarithm of th e minimum angle of resolution logMAR. T he minimum an gle of reso lut io n is th e in verse of the Snellen fr acti on.
The Ja eger 0 notatio n, wh ich assigns arbit rary nu m bers to Snell en equi valent figu res, is used by ma ny practition ers to expre ss near vi- su al acuity. Methods of calcu lating th ese acuities and det ailed compari sons w ith Snellen acuit y can be fou nd in textbo o ks th at are more co m p rehens ive. Test Targets Variou s tes t targets are used in visual acuity testin g Fi gure 4. Each ind ividu al lett er, number, or pi cture o n a testing chart is referred to as an optoty p e.
C hart s w ith such op to ty p es have achi eved alm os t u niversal accep tance in the U nited States. Some opto- ty pe s are mo re di fficult to recogni ze than others.
Fo r examp le, B a relati vely co m plex. Figure 4.
A, Sne lle n le tter chart. B, Alle n picture chart. Visual Acuity Examination This means that th e examiner can consider a patient's misinterpreting a B during ,;'" isual acuity testing to be less significant than missing an L. The tumbling E and Landolt C tests can be done by matching, but both involve some degree of laterality and therefore test psychophysical components other than visio n.
Picture charts are nonthreatening for young children but can result in over- estimation of visual acuity because, as with certain letters, the optotypes are not equally recognizable. Children easily learn the limited number of optotypes used, which can result in inaccurate acuity measurements due to educated guessing.
A test involving a chart and matching cards employing the 4 letters H, 0, T, and V is particularly useful with young children. These letters were chosen because they are symmetric, can be used for matching, and are useful with nonverbal or illiterate patients.
A newer procedure for testing visual acuit y using isolated HOTV optotypes sur- rounded by bar s is the Ambl yopia Treatment Study ATS visual acuity testing proto- col, and it is gaining wide spread acceptanc e for use with young children. Studies have demonstrated that this protocol has a high level of testability in 3- to 7-year-olds and excellent test-retest reliability.
Most charts have a notation either to the side or below each line of optotypes. When the patient can read at least one -half of the lett ers correctly in any given line, the size of that optotype becomes the denominator of the Snellen acuity expr ession for that patient.
The distance at which the patient is placed in reference to the chart is the numerator of th e Snellen expression. The examiner should also record whether the patient missed some letters on that line by adding the number of letters missed as a superscript notation to the acuity measurement.
Standard Abbreviations In addition to Snellen or other numeric notation, certain conventional abbreviations and notations are used in the patient record to indicate the type, circumstances, and results of visual acuity or visual function testing.
The most common of these are shown in Table 4. The use of these abbreviations in recording the results of patient testing is described throughout this chapter where individual tests are detailed. Table 4. N Near LP s proj Light perception without projection. Testing Procedures The most basic types of vision testing are the distance and near visual acuity tests. Even though they test 2 different aspec ts of fine-detail central vision, the se tests share some conventions , suc h as the use of corrective lenses and an estab lished order for testi ng each eye.
This section presents general background and specific steps fo r performing distance , pinhole, and near visua l acuity testing and for measuring nea r points of accommodat ion and convergence.
Distance Acuity Test O n an initial visit, a pa tient shou ld be tested bo th with and without co rrective lenses. When recording visua l acuity test resu lts in the patient's record, th e abbreviation cc ind i- cates tha t co rrective lenses were worn for the test. When vision is meas ured without the use of corrective lenses, the abbreviation sc is used.
O n subseq uent tests, a patient who habitu ally wears eyeglass es or co ntact lenses should wear them for the test, and it sho uld be document ed in the record. D istance cor- rection sho uld be use d to test dista nce vision. To avoid co nfusio n in recording inform a- tion, a testin g ro utine shou ld be estab lished.
T he righ t eye is tested first by con ven tion. C linical Protocol 4. A variety of occlu ders, held by either the patient or the examiner, can be used to cover the eye th at is no t being test ed. T hese include a tissue, a paddle, or an eye patch. T he palm of the patient 's or the examiner 's hand can also be use d to occlude th e eye not being tested. If a stan dar d occluder is not used, it is important to ensure th at the pa - tient cannot see thro ugh or aro un d it.
Any occluder that is used for mo re than 1 pat ient sho uld be cleaned befo re reuse. Visual Acuit y Exam inat ion Before th e test begins, de ter mine if th e patient is familiar wit h th e optoty pes being used.
Th is is part icu larl y imp ortant fo r child ren. If th e patie nt is co mfo rta ble with let- ters, use th at chart , if it is availab le.
If the pati ent prefers nu mb ers, use tha t chart.
If on ly 1 typ e ol chart is availabl e, a patient can quick ly memo rize the o rder of the optotypes, whe the r in ten - tionally or no t.
In this case, it is usef ul to ask the pa tient to read the lett ers in reverse ord er with th e seco nd eye. N ewer co mput erize d charts are part icu lar ly usefu l as the let- ters can be changed as ofte n as des ired. The typ e of cha rt and th e method of p rese nt ation used sho uld be not ed in the pa tient's reco rd; for exam ple, " isola ted nu m bers," " linea r letters," or "p ictu res.
Pinhole Acuit y Test A below-normal visu al acu ity can be the result of a refractive error. T his p ossibility can be inferred by having th e patient read th e testing chart throu gh a pinhole occ ludcr. The pinhole admits on ly cent ral rays of light , which do not requir e refr action by the cornea or th e lens. If the p inh ole impro ves the pa tie nt 's acuity by 2 line s or mor e, it is likel y that th e patient has a ref ractive erro r.
If poor uncorrected visual acuity is no t impro ved with the p inhole, the patient 's red uced visual acui ty is likel y du e eithe r to an extre me refractiv e erro r or to no nrcfractivc causes eg, op tic neuropa thy. H o wever, lack of im- provem ent o n pi nh ole test ing does not ru le o ut refracti ve erro r, as so me patients simply do no t perfo rm the test well. A pinh ole no more th an 2. O ne co mmon ly used mu ltiple pinh ole d esign has a cent ral ope ning surround ed by 2 rings of small perforati ons.
C linica l Protoco l 4. Patient s sho uld be positione d as for the dista nce acuity test, and the y sho u ld wea r their habi tu al op tical co rrec tion. T he test is don e fo r each eye separately and is no t re peated und er binocu lar view ing cond ition s. Nea r Acuit y Test N ear acuity testin g assesses th e abi lity of a patient to see clearly at a no rmal readi ng distance.
T he examiner sho uld det er mine whethe r or not the patient uses near spectacles and, if so, the pati ent shou ld usc th em d uring nca r vision tes ting. Occasio nally, as with patient s who are bedridd en or w ho are examined in the emerge ncy room , near vision testin g might be the onl y available metho d of measuring visua l acuity. T he test is usually per formed at 16 inches 40 cm wit h a printed, handheld card FIgure 4. If the distance is no t accur ate, the nea r visual acui ty measuremen ts will not be equiva lent to the distan ce acuity.
Most test cards sp ecify in writing the distance at which the y are to be held to co rrelate properly th e measur ements with those obtained for distan ce acuit y. Som e near read ing cards co me eq uipped with a chain that is 40 cm lon g to facilitate o btaining an accura te testing distan ce.
C linica l Protocol 4. For childre n, ncar visual acuity can be tested with Allen red uced picture card s, the Light ho use pictur e car d, the H OTV equ ivalent cards , or the Lea figure set.
As with the Snellen chart, th e near test card shows numeric notations alongside each line of optot ypes. Mos t cards should have an equivalent Snellen acuity fraction next to each line.
Other notations might also be present , the most common being the Jae ger not ation, also referre d to as] nu mber acuity. Other Tests of Near Vision N ear vision depends not only on th e eye's focusing ability, but on the near point of ac- commodation N PA , a monocular attribute, and the near point of convergence N PC , a binocular character istic.
T he NPA is the nearest point at which th e eye can focus so that a clear image is formed on the retina. With increasing age, th e N PA recedes, a condi- tion referred to as presbyopia.
Clinical Proto col 4. T he distance noted when measuri ng the NPA, if expressed in meters, can be conve rted int o diopters. A Prince or RAF Roya l Air Force rule th at has distance and dio pters noted on th e side is attac hed between the eyepieces of some ph oropters and can be used for the conv ersion. Th is inform ation is useful in determining the add pow er that will be needed for cor rective lenses, or in assessing residu al accommo dative capacity.
Th e NPC is th e nearest point to which both eyes can move nasally converge and still maint ain a single image. Th e normal NPC is between 6 em and 10 cm, ir respective of age.
Acuity Tests for Special Patients Patients with extremely low vision need special testing. Infants and toddlers, as well as illiterate adults and non verb al patient s, also need special testin g meth ods and attentio n. Low-Vision Testing If a patient is unable to read th e largest line of the visual acuity testing chart at th e stan- dard distance, repeat the acuity test at successively shorter distances.
For example, re- peatedly halve the distance between the patient and th e chart. In this situ ation, note the distance at wh ich th e acuity measur ement is successfully taken. For example, the notation indicates that the patient read the line successfully whil e standing 5 feet in front of the chart. H the patient is un able to read the standard chart even at extremely close distances, the examiner can hold up fingers and ask the patient to count them.
The patient with extremely low vision can also be asked to recogni ze the examin er's hand movements or identify the position of a penlight. Accepted abbreviations for recording low-vision test results are noted in Table 4. Clinical Protocol 4. Testing Children and Special Adults Many toddlers are uncomfortable with strangers, and most do not want to be touched by someone they do not know.
For these reasons, the examiner should allow these chil- dren to sit with a parent or other familiar caretaker and approach them slowly to avoid frightening them.
Ask the parents questions regarding their child's visual behavior, such as whether their child recognizes their faces from a distance, responds to their smiles, or uses visual or auditory clues to identify objects or people.
With infants and preverbal children, an estimation of visual function can be made based on the ability to look directly at fixate a visual object, follo w the object, and maintain steady fixation. Infants with normal visual function are able to manifest steady fixation and to follow an object by approximately age 2 or 3 months.
Newborns should show a consistent blink response to a bright light, even through closed eyelids while they are sleeping. Teller acuity cards discussed later in this chapter can be used to obtain a more formal measurement of infant visual acuity. Clinical Proto- col 4. Compare the infant's visual following responses, testing each eye separately with the other eye covered with a hand or a patch.
H 1 eye fixes or follows better than the other eye, amblyopia or another cause of reduced vision should be suspected. If the infant objects only when 1 eye is covered, a difference in vision between both eyes should be strongly suspected. Fixation preference testing, usually using the induced tropia test, is a useful adjunct for detecting amblyopia in preverbal children.
Teller acuity cards, if available, can be used to estimate acuity Figure 4. These cards are large photographic plates approximately 3 feet x 1 foot with line gratings printed at 1 end. Cards are presented to the infant with progressively smaller line grat- ings.
The examiner looks through a central pinhole to determine the baby's direction of. The baby will look preferentially toward the side of the card that has a discernible image. Once the resolving ability of the eye has been surpassed, the baby's gaze will be random. These cards are reliable until a child is approximately 1 year of age. The examiner must be experienced to obtain reliable acuity measurements, lighting mu st be good, and the cards must be kept meticulously clean. Detailed testing and interpretation inst ructions are included with the test kits.
As an alternative testing method, optokinetic nystagmus OKN can be elicited us- ing any regularly striped object.
This can be as simple as lines drawn on paper or a stan- dard tape measure, or as formal as a commercially produced OKN drum Figure 4. In all cases, the stripes are passed slowly and steadily in front of the baby while the examiner observes the movement of the baby's eyes.
Fine oscillatory movements, with the slow phase going in the direction that the stripes rotate, indicate that the baby has a potential for discriminating detail of at least the width of the stripe. Neurologic impli - cations in the interpretation of the OKN response are covered in greater detail in more advanced texts.
Horizontal OKN should be present by 3 months of age, whereas vertical OKN might not be elicited until a child is approximately 6 months of age. Toddlers and preliterate children as well as illitera te or nonverbal adult patients might be tested using a picture chart, the Landolt ring test, the tumb ling E chart, or the HOTV chart and cards. When the HOTV chart and cards are used, the patient may be given a card with the 4 letters marked in large print.
The patient is asked to point to each letter in turn, as the examiner presents them on a separate screen or chart from a specified distance. The appropriate equivalent Snellen notation is then made, with an addendum that the optotypes were H, 0, T, and V.
The protocol is automated on these instruments, so that the exam- iner only needs to indicate correct or incorrect. The surround bars are used to induce the crowding phenomenon, which makes the test more sensitive for amblyopia. In the screening phase of the ATS visual acuity protocol, single letters are presented in descend ing 10gMAR sizes until one is missed. In the testing phase , letters are shown, starting 2 10gMAR levels above the missed level in the screening phase, to determine the lowest level at which 3 of 4 letters are correctly identified.
In the reinforcement phase, the child is shown 3 larger letters starting 2 levels above the lowest correct level in the testing phase to get the child, whose attention might be drifting, back on track. In th e retest phase, the child is given a second chance on the last level missed in the test phase; if 3 of 4 levels are correctly identified, the test continues at the next smallest line until a. Fig ure 4. Th e visual acuity score is the lowest level at which 3 of 4 letters are cor- rectly identified in th e testing or retesting ph ase.
To help det ermin e th e most appro priate test, the examiner sho uld ask whether th e patie nt knows lette rs of th e alphabet or numbers, because many patients can ident ify specific lett ers or numbers even th ough they canno t read.
Some of the pictures are more readily recognizable than ot hers, and th ere are only a limited number of pictures. There- for e, th e use of pictur e chart s genera lly leads to an overestimation of the child's visual abilit y and is a less sensitive meth od of det ecting mild amblyop ia. Youn g children often beco me bor ed very quickly with vision testing.
Some children do bette r with numbers; others pr efer letters. If a child seems bored or hesitant with 1 kind of chart, try ano ther. Wh en using the Landolt ring chart , you can position yo ur self and th e parent as with the tumb ling E chart and ask the child to indi cate, for example, which side of the "cookie" has a bite in it.
Some very shy children will not talk but can be coaxed into whi speri ng the answer to a parent. Positive reinforcement, such as cheering for cor- rect answers , can encourage a child to com plete the test. Variables in Acuity Measurements Falsely high or low acuity measurements can be obtained und er a variety of circum- stances.
In genera l, th e near and distance acuities should be comparable unl ess myopia is pr esent. Po ssible causes of near acuity being poorer than dista nce acuity include th e follow ing:. O ther conditions can cause variability in acuity measur emen ts for both near and distance. Examples of externa l variables include the following:. Wh en a pro jecto r chart is used, th e cleanliness of th e pro jector bulb and lens and th e con - dition of the proj ectin g screen will affect th e cont rast of th e lett ers viewed by the patient.
The sharpness of the focus of a projected chart and the incidental glare on the screen can also influence the patient's ability to read the optotypes. Optical considerations also influence the ability of the patient to discern detail. They include the following:. Dirty lenses of any kind , whether tria l lenses, phoropter lenses, eyeglass lenses, or contact lenses, will decrease acuity, and the measurements obtained will be falsely low. Discussions regarding the prescribing of these lenses can be found in specialized clinical texts.
In latent nystagmus, a condition that occurs only when 1 eye is occluded, the unoccluded eye develops nystagmus and the measured visual acuity will be lower than expected and significantly lower than the binocular acuity.
In thi s situatio n, the patient ma int ains a head positi on to de crease th e amp litu de of th e nystagm us. Visual acuity wi ll imp rove w he n th e head is held in that po sitio n.
If the pa tient assumes a hea d position when loo king at ob ject s, determ ine if thi s improves acuity by allowing th e pa- tient to maintain that head position wh ile yo u measure bi nocu lar visual acui ty for distan ce and near.
The ano malou s head positi o n ma y also be allow ed fo r mo nocul ar visu al acuity testing, as long as it do cs not cause th e p atient to see aro und the occiud cr o r fogging lens.
Frequ ently patients w ith co nge n ital nyst agmu s w ill have significantl y bett er visua l acuity for near than for dist an ce.
This occ urs if the nystagmus da mp ens w ith co nve rgence. Psychol ogical factors, w het he r cons ciou s or u ncons cio us, affect visual acu ity mea- sure ment results.
In an atte mp t to p lease the examiner or par entis o r to "score" bett er on th e test , ch ildren might tr y to p eek aro un d the occluder. Fam iliarit y wit h the test can also lead to ina dve rte nt mem ori zati on of the lin es by the pati ent. Externa l variables suc h as p atie nt distraction, fatigue, and age should be con sidered when an u nexplained poo r acuity measurem ent is obtained. So metimes, thi s acu ity can- not be ach ieved with op tical co rrectio n suc h as eyeg lasses or con tac t lenses.
The terms visual impairm ent or visual acu ity imp airm ent arc used to describ e th is situ ation. Visu al impai rment is no t th e same as a visua l disab ility, wh ich impli es a subjective jud gment by th e exami ner. T he World Health Organization divides low visio n int o 3 catego ries based on visual acu ity VA an d visua l field.
T he criteria fo r th e catego ries based on VA are as follows:. Visu al acu ity is an impo rt ant facto r th at th e exa miner may use to make estim ates regarding a patient's potential disability.
T he acu ity level is co nside red w hen d et erm inin g read ing aids and read ing di stances. T hese facto rs are su m ma rize d in Tab le 4. Sever e visua l imp airment in bo th eyes is requ ired fo r inclusio n in th e category " legal bli ndness " and is th e crite rio n usu ally used to de ter mine eligibility for d isab ilit y be ne fits.
The disab ling effect, if any, of a visua l imp air me nt dep end s up on th e ind ividu al an d might or mig ht not be p erceived b y the patient as a d isab ility.
D efinitio ns of legal blindness d iffer from state to state, especially regardi ng eligibility fo r a d river's licen se. Gross orient ation and mobility cm cannot be binocular: CF 8 ft t o Unreliabl e vision Increasing problems with 4 ft visual or ientation and mob ility. Lon g cane is useful to explore env ironme nt. Talking dev ices and vision subst it utes are useful. Less than Nea rly tota l Vision unre liab le, except under CF 4 ft bli nd ness idea l circ umstances; mu st rely on nonvisual devices.
NLP Tot al blind ness No ligh t per ception: Academy of Ophthalmo logy in a Polic y Statement regardi ng vision requirements for driving. The guidelines for issuing no nco mmercial driving licenses also includ e the rec- ommendation that an uninterrupted visual field of horizontal diame ter be prese nt 0.
Amblyopia Am blyo pia, when unilateral, is a visual disorder defined as a difference in optically cor- rectable acuity of mor e than 2 lines between bot h eyes that results from abnormal visual input in early childhood.
The lay term for amb lyopia is "lazy eye. Am blyopia results when ther e is an inte rruption of this process. Causes of unilateral amblyopia include anisometropia, strabismus, and unilateral media opacities such as monocular congenital cataracts. Amblyopia can also be bilateral and can be associated with a variety of other conditions, including long-standing uncor- rected refractive errors and nystagmus.
Causes of amblyopia are dealt with in greater detail in other textbooks of clinical ophthalmology. In general, the younger the patient, the more successful is the amblyopia treatment. Many patients with amblyopia exhibit the "crowding phenomenon," in which smaller optotypes can be correctly identified when they are viewed singly rather than in a line with figures on both sides.
As a result, many amblyopic patients correctly identify the first and last letters of a line more easily than those in the middle. If visual acuity is checked using isolated figures, it should be recorded in the medical record. The crowding phenomenon is not specific to amblyopia. Although many practitioners end treatment when a patient is age , evidence in- dicates that some improvement in vision can be achieved in older children and teenagers.
Therefore, a trial of amblyopia therapy may be attempted in an older child after a thorough discussion with the parents and the child of the benefits and drawbacks of such treatment.
Ot her Tests of Sensory Visual Function Contrast sensitivity refers to the ability to discern relative darkness and brightness and the ability to see details, edges, or borders of images. Contrast sensitivity can be impaired even in the presence of excellent Snellen acuity. Alterations in contrast sensitivity imply abnormalities in the anterior visual receptive systems, from the tear film to the optic nerve. Specific patterns of alteration of contrast sensitivity function are discussed in more advanced tcxtbooks.
In the simplest contrast sensitivity tests, patients are shown printed charts with con- trasting lines, referred to as gratings, which are presented in varying orientations. The difference in the intensity between the background of the chart and the printed lines is gradually decreased, and the patient is asked to identify the direction of the lines. The end point is reached when the patient can no longer correctly identify either the presence of any lines or the direction of their orientation.
Testing methods that are more technical involve presenting grating patterns or letters on an oscilloscope screen. The end points and reporting methods are similar in both techniques.
Glare occurs when light from a single bright source scatters across the visual field, reducing the quality of the visual image. The perception of troublesome glare, which causes distorted vision and, in some cases, mild pain, can be a symptom of cataract.
As with Contrast sensitivity testing, glare testing by exposing the patient to bright light under controlled circumstances can suggest the presence of cataract or other opacity. The most commonly recognized color vision abnormalities are the x-linked congen- ital red-green deficiencies, but many other color vision anomalies exist. Optic nerve or retinal disease can result in color vision defects that can be acquired or asymmetric.
Most patients with inherited color vision defects see red as less bright than normal individuals s: Although not disabling, color vision anomalies can Impair performance in some careers or activities. However, colors can often be altered to accommodate those who have difficulty discriminating certain shades, as is available in some computer graphics applications.
Evaluation of color vision is often performed with a book that displays multicolored dot patterns, called pseudoisochromatic color plates. Pat ients with normal color vision easily detect specific numbers and figures composed of and embedded in the dot pattern, but patients with impaired color vision do not detect the same numbers or may not de- tect any numbers.
Various combinations of colors are used to identify the nature of the color vision deficit. Another test of color vision, the IS-hue test Farnsworth-Munsell D-lS test , con- sists of 15 pastel-colored chips, which the patient mus t arrange in a related color se- quence.
The sequence is obvious to patients with normal color vision, but patients with color deficits arrange the chips differently. Principles and performance of contrast sensitivity, glare, and color vision testing are covered more thoroughly in other, more detailed textbooks and in manufacturer's instructions that accompany testing materials.
Ensure that all lenses, projectors, and charts are clean. Alert the patient to your movements beforehand, particularl y if there is severe visual impairment. Offer an arm to the patient, but do not attempt to grab his or her hand or arm.
Most of these patients have some useful vision, and many of them will amaze you with their resourcefulness. Infants and young toddlers will respond best to a gentle, gradual approach and to the use of interesting toys to assesstheir fixing and following behaviors.
Clinical Optics. Basic and Clinical Science Course, Section 3. American Academy of Ophthalmology; published annually. Frisen L. Clinical Tests of Vision. New York: Raven Press; Pediatric Ophthalmology and Strabismus. Basic and Clinical Science Course, Section 6. Visual Rehabilitation [Preferred Practice Pattern].
American Academy of Ophthalmo logy; V isual Acu it y Exam in at ion Ask t he patien t to stand or sit at a designated testing d istance 20 feet fro m a well-illuminated wa ll chart is id eal. If a projected chart is used, distance may vary; t he p roj ect ed optotype size m ust be fo cused and adjus t ed to be equ ivalent t o the co rrespo nding Snelle n acuity for the dista nce used.
O cclud e t he left eye. Be sure t hat t he occlu de r is no t to uching or pressing ag ainst the eye. Observe th e pa t ient d uring t he t est to make sure th ere is no conscious o r inadvertent peekin g. A sk t he p at ient to say aloud each lett er o r num ber, o r name th e p ictu re objec t on th e lines of successive ly smaller op totypes, from left to righ t o r, alte rnat ive ly, as yo u po int t o each character in any o rde r, unt il th e pat ient correc t ly id entifies at least o ne-half of the o ptotypes o n a line.
If a pat ient is hesit ant at t im es for fear of bein g wrong , te ll him o r her th at it is all rig ht t o g uess. Not e t he co rrespond ing acuity measuremen t shown at th at line of th e chart.
Record th e acuity value for each eye sepa rate ly, wit h cor rectio n and with out co rrect ion, as illust rated below. If acuity is wor se t han , recheck wit h a pin ho le see Clinical Prot oco l 4.