1 - Angelfire



Monday, 4/2/2001 – 8 a.m. The scribe fools - Joe/Eric

ICM - Dr. Morales

Basic Eye Exam

Dr. Morales stressed at the beginning of lecture that it is important to incorporate the eye exam into our physical exams now or we will never do them.

I. The eye exam—must be organized & in order: (so that you don’t miss anything)

A. Check Visual acuity

B. Perform Confrontation field test

C. Examine lids and surrounding tissues

D. Examine conjunctiva & sclera

E. Check extraocular movements

F. Examine pupils (direct, consensual, APD – afferent pupillary defect)

G. Examine cornea & iris

H. Check anterior chamber for depth & clarity

I. Observe lens for clarity through direct opthalmoscopy

J. Conduct direct opthalmoscopy (fundus, including disc, vessels, and macula—examine last)

K. Use tonometry if indicated (IOP > 22 mmHg)

• A Snellen eye chart is used to measure visual acuity in a standardized fashion (20/20 is normal. With

the chart, can objectively record deviations from normal)

• Follow the above order when performing eye exams.

II. Testing distance visual acuity

A. Standard distance between the chart and patient is 20 feet or 6 meters

B. Use good illumination

C. Make sure patient is wearing glasses if needed (distance correction)

D. Occlude/cover one eye (beware, some patients may cheat to get the answer right, especially children)

E. If vision is less than 20/40 (20/200 etc), try using a pinhole occluder

• Tell patient to use the cup of their hand to cover their eye so that they can’t put pressure on the eye. (when using fingers, the tendency is to press on the eye and cause their vision to be blurry)

• The pinhole occluder (can use a card with a small hole poked in it) increases depth of focus, it is used for

people with refractive error for people who normally wear glasses; it’s an optical error.

III. Visual acuity—what does 20/20 mean?

A. Visual acuity is a measurement of the smallest objects identifiable at a given distance in a standardized fashion.

B. Numerator: distance between patient and the chart (start with the standardized distance of 20 feet)

C. Denominator: distance in feet at which letters can be read by a normal individual (ex 20); can go as high as 400; which is the big "E" on the chart

• Basically, if someone is 20/400: what they see from 20 feet is what someone with perfect vision can see from

400

• Tell the patient to read the lowest line that they are able to, if it is 20/20, then you are done, if not then you need to assess further.

• Remember, if patient has trouble reading the chart ask them to use the pinhole occluder (probably just can’t

see without their glasses)

IV. Abbreviations we need to know

A. V.A.: Visual Acuity

B. O.D.: Oculus Dexter or right eye

C. O.S.: Oculus Sinister or left eye

D. O.U.: Oculus Uterque or both eyes

V. If patient cannot see Snellen eye chart letters (not even the big ‘E’):

A. Reduce distance—move chart closer; must change the numerator (10/400 etc)

B. Count fingers assessment (“how many fingers do you see,” make sure patient is not just guessing, don’t lead the patient. “Can you see my 5 fingers?)

C. If the patient still can’t see, use the hand motion assessment (don't lead the patient, "can you see me waving my fingers—yes," rather ask what direction your fingers are moving)

D. If the patient has minimal vision use light perception and projection (patient gives the location of light. Is the light on or off?)

VI. Near visual acuity testing—when away from the office

A. A reading card can be used: appropriate at bedside or if you lack a distance testing chart (less accurate, but still good; see [fig 1.6] on pg 11 of the text. (Most usual for patients in the hospital.)

B. Make sure reading glasses are on if needed (after 20 you start to lose accomodation; by the time you're 40 your compensatory mechanisms are inadequate and most people need reading glasses)

C. Standardize—distance is specified on the card (14 inches is typical, standard reading distance)

D. Cover one eye

E. Reading cards use Jaegger notation (J1, J2, etc) or distance equivalent (J1 = 20/20, J2 = 20/40, etc)

Jaegger rulers are very useful in the examination of patients, has a ruler also to measure pupillary diameter.

VII. Visual Impairment vs. Visual Disability

A. Up to 20/25: Normal

B. 20/30 to 20/70: Near-normal

C. 20/80 to 20/160: Moderate low vision

D. 20/200 to count fingers assessment (CF) at 10ft: Severe low vision (Legal blindness) Can get medical disability at this level.

E. CF 8ft to CF 4ft: Profound low vision

F. Counting fingers at 4ft or less: Near total blindness

VIII. Referral guidelines for decreased visual acuity:

Unless seen recently by an opthalmologist & stable, the patient should be referred for an eye exam if:

A. VA between 20/20 and 20/40, but patient has symptoms (may just be a problem with their glasses)

B. VA < 20/40 (20/200 etc) there is probably something wrong

C. Asymmetry of 2 lines between eyes

D. Presbyopia (aging—patient needing reading glasses)

• Remember, an optometrist has no medical degree and usually only prescribes glasses etc., while an MD looks

for diabetic retinopaty, can perform surgery etc. (Determine which the patient is seeing for their eye exams)

• If patient can see 20/40 with pinhole, then nothing is probably wrong, but if they can’t, then they need to see an opthalmologist.

IX. General Visual Inspection of Patient—remember to go in order

A. Lids (look for swelling, droopiness) – Does it look normal

B. Surrounding tissues

C. Palpebral fissure (look at width—wider with thyroid disorder, Grave’s disease, etc)

D. Conjunctiva (thin superficial layer) and sclera (white tissue)

E. Cornea and iris (diaphragm of eye, forms the pupil—through which you can see the back of the eye)

• Showed a picture of Arcus Senilis—fairly common in older patients, a light colored ring around the iris (can

also occur in patients with high cholesterol); a pigmented increase in elevation of the sclera may indicate

melanoma; to see what retinae can look like see the slides on pp 14-15 of the text

• Showed a picture of subconjunctival hemorrhage—a superficial bruise (looks worse than it is, can no longer

see white of the sclera because it is blood red), the patient can still see fine; if patient is on anticoagulants

may be a warning sign of bleeding elsewhere

• Remember to be familiar with the surface anatomy of the eye, It is important!

X. Pupillary exam (very important)

A. Make sure the pupils are regular, round, equal on both sides (write it down)

B. Make sure they are equal in bright light and dark conditions (shine light from below)

C. Must have direct pupillary reaction to light, should be brisk and immediate

D. Must have consensual response (the other eye is also reacting to light)

E. Look for presence or absence of afferent pupillary defect (Very Important – it means there is a very serious problem with afferent input into the eye.)

• He showed a schematic emphasizing that in a direct response the same eye that the light is shown in

constricts while in indirect responses it is the opposite eye that constricts

• He showed another schematic explaining relative afferent pupillary defect—when alternating light between

eyes there should be minimal change in the pupil; if light is shown in one eye and it dilates while the other

eye functions normally this is indicative of serious defect (usually correlates to poor vision in one eye, if

both eyes have poor vision then it is not a ‘relative’ pupillary defect)

XI. Ocular motility testing—make sure the eyes are aligned

A. Ocular alignment: can test using the light reflex or cover-uncover test

B. Make patient follow objects in the different cardinal fields of gaze

• Use the light reflex & compare pupils—if the reflex is seen outside of the pupil (eye inverted) they are not

aligned

• He then showed a schematic explaining the cover-uncover test—if the eyes are not aligned and you cover

one eye, it will move when uncovered to center itself [see fig 6.5 for clarification]

• He showed a schematic of the various fields of motion used to test ocular muscles

• There are some children who have pseudo-strabismus, where it looks like the eyes are crooked, and the cover-uncover test can help differentiate this.

XII. Direct opthalmoscopy (Fundus exam)—learn this, can provide lots of info

A. Examine the right eye with your right eye (and the left with your left), this is more comfortable (and will help you avoid that inevitable "look me in the eye" kiss)

B. Remove glasses of examiner & patient (use dials to adjust for refractive errors that you & the patient might have)

C. Contacts lenses are ok

D. Get close (this is important for we won't see anything otherwise, he suggested we think of ourselves as peeping toms or poor medical students that can't get into a ball game but have to get up real close to a hole in the fence to see what's going on) if someone says they can see everything without getting close—they’re lying!

E. Have the patient look straight ahead

F. Start by focusing the wheel at +8, giving you a large, round white light (+8 to +10 enables you to see anterior structures, such as the lens, as well as interior structures such as the fundus)

G. Find red reflex

H. Place other hand on the patient's forehead or shoulder to stabilize yourself

I. Get closer—find vessels, refocus—find optic nerve

J. Examine disc, vessels, retina, & macula (see diagram [fig 1.7])

“The pupil is the window to the eye and the eye is the window to the body,” there is no other place in the body that you get unobstructed views of vessels (can see veins, arteries, pulsations; optic nerve is an extension of the brain) can make many diagnoses using direct opthalmoscopy.

• Myopic patients – you will use the negative numbers on the opthalmoscope to view the back of the eye

• Patients c/o lenses/removed cataracts – you will the positive numbers

XIII. Retinal background:

A. A uniform red-orange (is a combination of the reflection from choroidal blood vessels & pigment from the retinal layer)

B. When taking pictures, this is what gives people "red-eye"

C. When we're examining the patient, we are only seeing segments of the retina

D. Remember that vessels go from thin to thick towards the optic nerve, veins look darker than arteries (although not blue like in text books), look for excavation, and the macula. Arteries are usually thicker and veins are thinner. Make sure there are no hemorrhages where arteries and veins cross, that’s a significant finding.

XIV. Retinal Circulation

A. Spontaneous venous pulsation occurs in 80% of patients (this disappears in patients with papilledema)

B. Arteries are narrower and lighter than veins

C. Vessels are thinner as they get far from the optic disc

D. Ratio of Veins to Arteries is 3:2 (can change with disease, hypertension)

E. Arterial/Venous (A/V) crossing patterns are useful (ex: hypertension—arteries may compress veins)

• Optic disc is more nasal

• Macula is located temporally—gives 20/20 vision, if damaged (hypertension, macular degeneration etc):

patient becomes 20/400 or worse; save macula for the end of your eye exam (most sensitive)

XV. Macula

A. Found temporal to optic disc

B. Darker than surrounding retina

C. Responsible for finest part of vision (sensitive)

D. No blood vessels

E. Foveal reflex is more evident in younger patients (shinier)

• Central excavation of the disc is typically 20-30%, if higher it may be indicative of glaucoma

• If you can’t find the macula, then have the patient look at the light and that’s where it should be. It’s very sensitive, so you want to save this part for last.

XVI. Optic Disc

A. Nasally located

B. Slightly oval (vertically)

C. Central depression: Physiologic cup

D. Yardstick of ocular fundus, for ex: “lesion is 2 disc diameters” [1 disc diameter (dd) = 1.5 mm]

• He showed a picture of an optic disc with large excavation (nerve tissue that has grown): looks like a

doughnut, if see this type of cup to disk ratio patient must be referred for possible glaucoma

• In patients with papilledema the optic disc looks fuzzy (possible tumor, increased intracranial pressure etc)

XVII. Pupillary dilation

A. Drugs: Tropicamide 1% and Phenylephrine hydrochloride 2.5% are typically used (bottles have a red top)

B. Avoid dilation if:

1. Shallow anterior chamber

2. Patient is under neurologic observation (can’t follow pupils)

3. Square pupil from intraocular lens (implanted before 1984—these lenses were attached to the iris and could fall through the pupil; nowadays lenses are attached behind pupil)

C. Explain to patient the purpose, duration, side effects (blurry vision for 2-3 hrs), and precautions

• Do not use Atropine! It can last up to 15 days [use drugs such as Phenylephrine hydrochloride 2.5%

(cyclomidryl)]

XVIII. Anterior chamber depth assessment:

A. Iris bowing forward causes shallowness

B. Use pen-light from the temporal side, parallel to iris plane

C. Light should illuminate iris surface uniformly (if bowed, will cast a shadow; see [fig 1.9])

D. Compare both eyes

E. Experience needed

• Just be aware that patients with narrow angles can have problems with dilation

XIX. Intraocular Pressure Measurement:

A. Mostly a result of aqueous humor outflow impairment (leads to buildup of pressure)

B. Usual range: 10-21 mmHg (anything higher is abnormal) Remember This!

C. Part of glaucoma screening

D. Various instruments used: Non-contact and contact

• Optometrists do the ‘puff’ of air test

• Opthalmologists use Schiøtz or Goldmann tonometry—anesthetic drops are given & a scale is used to measure corneal indentation “Gold-Standard”

XX. Referral guidelines for intraocular pressure: IOP > 22 mmHg – Refer the patient to an opthamalogist!!!

XXI. Confrontation field testing (comparing your visual field with the patient’s)

A. Sit in front of the patient, cover one eye (sitting opposite the patient, so if you cover your right, they cover left)

B. Examine right eye (OD) with your left eye (OS), and left eye with your right eye

C. Ask patient to count fingers adding different quadrants

D. 1, 2, or first finger presented; do not move fingers (remember: peripheral vision is not very good)

E. Re-check suspicious areas

• Ask the patient, “how many fingers do you see,” and proceed checking many quadrants

XXII. Color vision testing

A. Check if suspected color blindness

B. Also check if retinal or optic nerve problems

C. Use standard plates (Ishiara plates are most commonly used—typical color blindness tests)

D. Make sure patient is wearing near vision glasses if needed

E. Report the number of correct responses/plates (ex: field of blue dots with green dots forming a number—“what number do you see?”)

XXIII. Upper lid eversion

A. Used to search for conjunctival foreign bodies (see [fig 1.10])

B. Patient should be looking down

C. Use a Q-tip and pull on lashes to flip lid over—will stay up due to “tarsal flight” (you may have done this as a kid to scare people, or just as a fashion statement in the early 80’s) can then search for foreign bodies, useful in the ER.

XXIV. Fluorescein Staining of Cornea

A. Shows defects of corneal epithelium (see slides on pg 21 of the text)

B. Fluorescein is a yellow dye

C. Moisten strip and place in lower cul-de-sac

D. Cobalt blue is used for visualization (a bluish light: sometimes pen lights or opthalmoscopes have this feature)

E. Defects will stain green under blue light

F. Make sure patient removes contact lenses (especially soft lenses) to avoid staining (unless they like green tint)

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