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NYU

PGY-

Ophthalmology

Basics Guide

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PREFACE

NYU offers its medical students an elective course in Ophthalmology. Oftentimes, students start the elective and find that they are unfamiliar with the “ophthalmic lingo,” ophthalmic history, and especially the ophthalmic consultation note.

This compilation addresses the format of the eye examination, focusing on familiarizing the student with the eye examination, as well as translating information recorded in the eye note. A brief glossary of drugs and ophthalmic terms, as well as an explanation of notations, abbreviations, and acronyms is included. In addition, guides in helping the student with specific ophthalmic techniques, such as Goldmann applanation and Schiotz tonometry, application of ophthalmic drugs, direct and indirect ophthalmoscopy, and examination of the pupils, is included. Lastly, general guidelines for ophthalmic follow- up as practiced by our residents is covered.

No guidelines for treatment or patient management is addressed. These must be learned through experience in the eye clinic, passing on skills from faculty to residents to students, and supplemental reading.

ACKNOWLEDGEMENTS

Information included in this compilation was obtained from the following texts:

1. Will’s Eye Manual. Cullom, Lippincott Raven Publishers, 2 nd^ Edition. 1994.

2. Ophthalmology Made Ridiculously Simple. Goldberg MedMaster, 1st^ Edition.

3. A Manual for the Beginning Ophthalmology Resident. American Academy of Ophthalmology, Custom Printing, Inc. USA, 3rd^ Edition. 1980.

4. Phillips C., Clark C., Tsokahara S. Ophthalmology: A Primer for Medical Students and Practitioners. Bailliers Tindall, London. 1994.

PRACTICAL CHECKLIST

Section A

You should do the following:

1) Take three full histories and write them down

2) Go through the full eye examination on at least three patients and

present your findings to a resident

3) Take and record distance visual acuity

4) Take and record reading (near) visual acuity

5) Use a pinhole

6) Examine ocular movements

7) Test convergence

8) Test the pupillary reactions

Section B

You should see the following:

a. Clinical cases

i. Cataracts

ii. Pseudophakia

iii. Diabetic retinopathy (several)

iv. Macular degeneration

v. Glaucomatous disc cupping (several)

vi. Chalazion, pinguecula, pterygium (several)

b. Tests to be familiar with

i. Visual fields

ii. Applanation tonometry (do yourself)

iii. Gonioscopy

iv. Amsler chart

v. Color vision tests

vi. Slit lamp biomicroscopy (do yourself)

vii. Indirect ophthalmoscopy (try yourself)

viii. Schirmer’s tear test

ix. Corneal staining with fluorescein strips (do yourself)

x. Intravenous injection of fluorescein with fundus

photography, and several fundus photographs

(In fluorescein angiography, an arm vein is injected with a

fluorescein material that is photographed as it passes

through the retinal vessels. The technique is extremely

useful in diagnosing and treating many conditions.

Fluorescein angiography is most frequently performed in

retinal vascular diseases: diabetic retinopathy, retinal vein

occlusion, and macular degeneration with choroidal

neovascularization. In diabetic retinopathy, angiography

may detect microaneurysms and areas of vessel leakage to

help determine which areas to treat with laser

photocoagulation.)

SAMPLE NOTE OF COMPLETELY

NORMAL EYE EXAM

Date: 4/3/

CC: Routine eye exam, first visit, no complaints

HPI: 38 year old WM w/ no significant PMHx

POHx: None PMHx: No HTN, no DM, no COPD Meds: None ALL: NKDA FHx: No glaucoma No diabetes

VA 20/ 20 20/ 20

TAP 15 mmHg EOM Full OU 10:15am 15 mmHg

DFE m1%, N2.5% SLE 10:25am L/A WNL OU C/D 0.3^2 OU, s/p/f C/S W&Q OU M + FR OU C Clear OU BV WNL OU AC D&Q OU R No heme, no exudates I/P ERRL no APD OU V Clear OU L/M Clear OU

IMPRESSION/PLAN: Normal eye exam

RTC: 3-5 years or sooner prn

PGY-

NOTATIONS, ABBREVIATIONS, AND

FREQUENTLY USED ACRONYMS

VA Visual acuity: the cc or sc means with or without correction. PH means that a pinhole was used. If vision improves with PH, it may indicate a refractive error. If vision does not improve with PH or refraction, you must rule out any pathology for decreased VA

TAP Tonometry, or intraocular pressure (IOP) measurement. The letters AP stand for the method used, applanation. TS means Schiotz method of tonometry.

OD Ocular dexter – right eye OS Ocular sinister – left eye OU Ocular uterque – both eyes

SLE Slitlamp Exam: WNL within normal limits W&Q white & quiet (normal) D&Q deep & quiet (normal) C/F cell & flare APD afferent pupillary defect (Marcus Gunn Pupil)

DFE Dilated Fundus Exam: S/F/P sharp, pink, flat (normal) FR foveal reflex (normal in children, young adults MA microaneurysms HE hard exudates D/B dot/blot hemorrhages CWS cotton wool spot M1%, N2.5% typical dilating drops Mydriacil (tropicamide) and Neosynephrine (phenylephrine)

ACIOL anterior chamber intraocular lens AION anterior ischemic optic neuropathy ALT argon laser trabeculoplasty APD afferent pupillary defect ARMD age-related macular degeneration BRAO branch retinal artery occlusion BRVO branch retinal vein occlusion CL contact lens CME cystoid macular edema CRAO central retinal artery occlusion CRVO central retinal vein occlusion COAG chronic open angle glaucoma

SPECIFIC OPHTHALMIC TECHNIQUES

A. Assessment of Visual Acuity

The most commonly used tests for visual acuity are the distance (Snellen) vision chart and near (Rosenbaum) vision chart. Each eye should be tested separately. When covering one eye, make sure that the patient is not pressing on the eye, as this may temporarily interfere with visual acuity when the covered eye is tested. 20/20 means that the patient can read, at 20 feet, the same number of lines that the average person can read at 20 feet. 20/200 would mean that the patient, at 20 feet, can read no more lines than the average person can read at 200 feet. Visual acuity may be recorded up to 20/400 or 20/800, but beyond that is recorded as FC (Finger Counting), HM (Hand Motion), LP (Light Perception), and NLP (No Light Perception). The patient should be tested with his/her glasses. Make sure you are using the distance glasses when testing distance vision and reading glasses when testing near vision. If wearing bifocals, make sure that the patient is looking through the top part of the glasses when measuring distance vision and the bottom part of the glasses when measuring near vision.

Examples of visual acuity recordings:

VA SC 20/400 PH^ 20/

20/50 (^) -2 PH^ 20/

This indicates that distance vision without correction is 20/400 OD and 20/50 –2 OS (the patient read the 20/50 line except for two letters). Both eyes pinhole to 20/30.

VA CC 20/60 PH^ 20/

20/70 PH^ 20/

This indicates that the distance vision with correction is 20/60 OD and 20/70 OS. The right eye only corrects to 20/25 with pinhole and the left eye corrects to 20/20 with pinhole.

Legal blindness is usually accepted by state legislators as visual acuity of 20/200 with best correction in the better seeing eye, and/or visual field restricted to a 20 degree diameter or less in the better eye.

B. The Direct Ophthalmoscope

The direct ophthalmoscope becomes much less challenging to use in this non-dilated patient once the student has had experience has had experience viewing many dilated pupils. If nothing else, it is hoped that anyone rotating through the clinic will feel comfortable using

the direct ophthalmoscope since both the ophthalmologist and non-ophthalmologist employ this instrument frequently. The instrument provides 15x magnification, and the image is real.

A diagram of the direct ophthalmoscope:

1. Mirror that reflects light into the patient’s eye with a viewing hole above, through which the examiner looks.
2. Handle where battery power is supplied. On top of the handle is a rheostat for light adjustment.
3. Headrest bar, which goes against the examiner’s forehead.
4. Viewing hole through which the examiner looks. It is this hole that lenses may superimpose for focus.
5. Focusing wheel, with which the examiner can, using their index finger, adjust the lenses in the viewing hole while holding the ophthalmoscope.
6. As the dial wheel is moved, the power of the lens is indicated in this small window. Red numbers indicate minus lenses, and black numbers indicate plus lenses.

How to Examine the Patient:

1. Use your right eye to visualize the patient’s right eye and your left eye to visualize the patient’s left eye.
2. Have the patient look straight ahead at a distant object.
3. Obtain a red reflex in the patient’s eye while looking through the ophthalmoscope. This is best achieved from a position about 15 inches away from the patient and about 20 degrees lateral to the patient’s line of vision.

illuminated with a blue or fluorescent light. A break in the corneal epithelium permits fluorescein penetration, and a bright green appearance of the affected corneal region results.

Ophthalmic drops and ointments should also be applied to the lower fornix in order to avoid irritating the cornea. The eye only accommodates a few drops, so there is little concern about applying too much, as the excess will not stay in the eye.

E. Tonometry

Assessment of intraocular pressure (IOP) can be done using one of many modalities. In our clinics, the slitlamps are equipped with Goldman applanation tonometers. Determination of IOP is important in the evaluation of glaucoma, traumatic injuries, inflammation, and retinal detachment, just to name a few conditions. This ophthalmic technique is called tonometry.

A diagram of the Goldmann’s applanation tonometer:

To use the instrument-mounted Goldmann’s tonometer:

1. Clean the tip of the tonometer with an alcohol swab. If an HIV+ patient’s IOP is measured, make sure the tip is sterilized and replaced with a new sterilized tip.
2. Check to see that the applanation prism is horizontally aligned at 180 degrees.
3. Instill a drop of proparacaine into the eye, then apply some fluorescein.
4. Position the patient at the slitlamp with the forehead firmly against the headrest, looking straight ahead of fixating on your ear.
5. Using the cobalt blue filter with the brightest beam projected at the applanation prism, center the prism directly in front of the corneal apex.
6. Preset the spring tension dial between 1 and 2 (between 10 and 20 mmHg).
7. Have the patient blink and gently advance the slitlamp, looking around until the tonometer just touches or is about to touch the cornea.
8. Quickly switch to viewing the eye through the ocular on the left hand side. Two semi- circles should be visible. The inner margins of the semi-circles should just kiss for correct IOP measurement.
9. All adjustments of the dial should be made with the instrument momentarily backed away from the cornea to prevent inadvertent corneal trauma.

10. Pulse pressures will create some fluctuations in the mire pattern. Diastole will separate the inner margins and systole will overlap them. Normal IOP’s are considered to range from about 8 to 22 mmHg.

Increase dial setting Decrease dial setting

Applanation tonometer mire ring patterns: Correct reading of IOP

The Schiotz tonometer is a portable hand-held instrument which makes is available for use in the emergency and operating rooms. The device has a footplate that fits directly over the cornea. In the center of the footplate is a hole through which a plunger moves. As the plunger indents the cornea, a pointer records readings on a scale. The plunger and its weight (adjusted by adding heavier or lighter metal disks) indent the cornea. The amount of indentation of the cornea depends upon the IOP. The higher the IOP, the less indentation; the lower the IOP, the more the indentation. Therefore higher scale numbers correspond to lower pressures, and lower scale numbers to higher pressures. One must always calibrate the instrument by positioning the footplate with the weighted plunger in place on a solid convex surface provided in the instrument case. The plunger, in this instance, should register at 0 (since there is no indentation), which corresponds to a very high pressure. With each tonometer, a chart for converting scale readings to IOPs in mmHg is provided. When using the tonometer, you should routinely start with a baseline weight of 5.5 g. If a reading less than 3.0 is obtained, heavier weights should be used until the scale reading is at least 3.0.

A diagram of the Schiotz tonometer:

The swinging flashlight test compares the direct and consensual responses in the same eye. It is used to document an APD, which is commonly found in optic nerve disease. Shine your bright light into one eye, watching the response. Then swing the light to shine into the other eye. The first reflex of that pupil is observed for miosis. If normal conduction is present in both eyes, crisp miosis occurs bilaterally as the light is swung back and forth. If, on the other hand, conduction is impaired in one eye, swinging the light from the intact eye to the impaired eye will produce paradoxical dilatation in the impaired eye. The direct response is less intense that the consensual response created a second earlier in that same eye. This finding is known as an afferent pupillary defect (APD) or a Marcus Gunn pupil.

Ambient Light (5mm)

Direct Light Reflex, OD (2mm) Consensual Reflex, OS

Swinging Flash… …light Test

Ambient Light (5mm) DEFECT NORMAL

Constriction Directly (4mm)

Constriction Consensually (2mm)

Paradoxical Dilatation (4mm)

GLOSSARY

A. Some Basic Ophthalmic Terms

Amblyopia partial loss of sight acquired during childhood (from strabismus, marked refractive asymmetry, or deprivation)

Ametropia condition in which there is a refractive error

Anisometropia ignificant difference in the refractive power of the eyes

Aphakia absence of the lens of the eye (e.g., after cataract surgery)

Arcus senilus opaque, grayish ring at the periphery of the cornea within the sclerocorneal junction, commonly seen in the aged, and most often resulting from a deposit of fatty granules

Amsler Grid a test useful in detecting subtle, early changes of metamorphopsia (visual distortion) in macular disease

Chalazion chronic granuloma in the tarsus due to inflammation of a Meibomian gland

Cyclopegia paralysis of accommodation due to loss of power of the ciliary muscle

Dermatochalasis herniation of orbital fat into the upper and/or lower eyelids, usually due to age

Diopter the unit of refracting power of lenses, denoting the reciprocal of the focal length in meters

Diplopia double vision

Emmetropia state of having no refractive error

Enophthalmos recession of the globe into the orbit

Esophoria tendency of the eyes to deviate inward (latent)

Esotropia crossed eyes inward (manifest)

Exophthalmos forward displacement of the globe

Exophoria tendency of the eyes to deviate outwards (latent)

Exotropia crossed eyes outward (wall-eyed) (manifest)

Strabismus ocular misalignment, whether due to abnormalities in binocular vision or anomalies of neuromuscular control of ocular motility

Symblepharon adhesion of the palpebral conjunctiva of the eyelid to the bulbar conjunctiva of the globe, often seen in Stevens-Johnson syndrome

Synechia adhesion of the iris to anything within the anterior chamber, usually adhesion of the iris to the anterior lens capsule as a result of the inflammatory process in anterior uveitis

Uveitis inflammation of any part of the uveal tract

B. Some Basic Ophthalmic Drugs

Eye medications should be listed with the current dosage regimen. You should ideally record the time of the most recent administration of the medicines for treatment of glaucoma. Most clinic patients cannot remember the names of their medications. Containers for eye drops have colored tops. Green tops generally indicate cholinergic drugs (pilocarpine, etc.); red is used for anticholinergic drugs (atropine, homatropine, cyclopentelate, tropicamide, etc.). Timolol and betaxalol are beta blockers packed in bottles with yellow and blue tops, respectively. Trusopt, a orange topped topical carbonic anhydrase inhibitor, is used for glaucoma. White tops are used for a wide variety of antibiotics, artificial tears, and steroids.

Acetazolamide Carbonic anhydrase inhibitor; sulfonamide wuth diuretic action in the (Diamox) renal tubules. Causes reduction in IOP by decreasing aqueous humor secretion. Indicated primarily in treatment of COAG

Alomide An ophthalmic solution containing the mast cell stabailizer lodoxamide tromethamine used for the treatment of vernal (allergic) conjunctivitis

Atropine Cycloplegic mydriatic; anticholinergic response blocks cholinergic stimulation of the iris sphincter muscle and ciliary body, producing pupillary dilation and cycloplegia. Used mostly for cycloplegic refraction in children, and to cause mydriasis and prevent synechiae formation associated with uveitis

Betaxolol Beta-adrenergic blocker; cardioselective beta 1 adrenergic blocking (Betoptic) agent (spares beta 2 pulmonary receptor). Reduces IOP by a decrease in aqueous humor protection. Used mostly in treatment of COAG

Cyclopentolate See Atropine

Dipivefrin Sympathomimetic; reductionof IOP occurs through he decrease in (Propine) aqueous humor formation and the enhancement in outflow facility. Used mostly in COAG

Epinephrine Sympathomimetic; action similar to dipivefrin

Fluoromethalone Corticosteroid; anti-inflammatory action exerted through suppression

of edema, vascularization, and fibroplatic proliferation. Used in treatment of inflammatory conditions of the palpebral and bulbar conjunctiva, lid, cornea, and uvea. This drug is used in preference to prednisolone acetate in steroid responders (patients who have elevated IOP with chronic steroids) since it has a lower propensity to increase IOP

Healon High molecular weight, high viscosity, transparent and non-antigenic Solution of sodium hyaluronate. Used as a surgical aid in anterior and posterior segment procedures, especially cataract surgery. It also protects the corneal endothelial cells and other ocular structures for up to 6 days

Homatropine Cycloplegic mydriatic; see atropine. This solution used primarily in treatment of iritis

Iopidine Alpha-adrenergic agonist that lowers IOP through the reduction in (Aproclonidine) aqueous production. Used mostly to control post-surgical rises in IOP occurring after laser trabeculoplasty or laser iridotomy

Latanaprost Synthetic prostaglandin; functions as an IOP lowering agent by promoting uveoscleral outflow of aqueous humor

Mannitol Hyperosmolar; systemic hypersmotic agent that results in an increase in serum osmolarity in the ocular circulation. This causes fluid from the eye to enter the ocular circulation resulting in a lowering of the IOP. Used most often for acute narrow angle attacks of glaucoma

Methazolamide Carbonic anhydrase inhibitor; see Acetazolamide (Neptazane)

Naphcon Decongestant; exhibits greater alpha- than beta-adrenergic activity. Used for temporary relief of minor eye irritations and vasconstricts conjunctival blood vessels Naphcon-A Decongestant/Antihistamine; like Naphcon but with added antihistamine effect. Used mostly for allergic eye condition (A=antazoline, an antihistamine)

Muro-128 (NaCl) Hyperosmolar; eyedrop which deturgesees corneal edematous fluid into a more highly osmotic tear layer

Ocupress Beta-adrenergic blocker; nonselective beta 1 & 2 adrenergic (carteolol Hcl) blocker. See Timolol

Ocufen Nonsteroidal anti-inflammatory; inhibits cyclo-oxygenase enzyme essential in prostaglandin biosynthesis. Used mostly in treatment of CME after cataract surgery

Phenyleprine Mydriatic; sympathomimetic with direct action on alpha receptors (Neo-synephrine, of the iris dilator muscle and smooth muscle of the conjunctival Mydfrin) arterioles. Mueller’s muscle of the upper lid is also stimulated, increasing the palpebral aperture. Used mainly for dilation for