Lecture IX: Examination of the Eye

Question 1

Principles for checking visual acuity

Answer 1

a. OD: Oculus Dexter = right eye (Spanish Derecha = right)
OS: Oculus Sinister = left eye
b. Monocular, No Squinting, No Cheating, With correction (glasses/contact lenses)
c. Measure Distance OD, OS; Measure Near OD,OS
• “Distance” = 20 feet= optical infinity
• “Near” = 14” = average reading distance (Be sure to use the appropriate chart for testing distance!)
d. Start at top of chart, read left to right, lowest line correctly read = acuity

e. Acuity documentation translation (#s in image above): The Visual Acuity was checked, and the right eye read all of the letters of the 20/40 line on the chart except for one letter; the left eye read all of the letters on the 20/20 line of the chart and one extra letter on the next-smaller line.

Va–> 20/40-1
Va–>20/20+1

Question 2

Checking visual fields by confrontation

Answer 2

Check Confrontation Visual Fields
• Position: Tester’s nose even with patient’s nose, same-side eye covered
• Principle: If tester can see it, patient should see it too
o “Confrontation”
• Method: Tester holds hand midway b/w noses, shows 1,2 or 5 fingers
• While keeping fixation on examiner’s eye, patient responds
• Test all 4 quadrants
• Confrontation fields documentation
• Notice: the fields are documented as the PATIENT SEES them, not as the examiner sees them – that is, the patient’s left field is written on the left side of the page. Areas not seen are shaded, areas seen are documented as “OK” or “intact”

Question 3

Steps of the Eye Exam

Answer 3

1. Check visual acuity
2. Visual Fields
3. Pupils
4. Motility
5. Volcano Sign
6. (slit lamp)
7. (dilate)
8. (examine retina and fundus with slit lamp)

Question 4

Measure pupillary light responses

Answer 4

Check Pupils (the Relative Afferent Pupillary Defect Test)
f. Dim room lights: just dim enough to allow examiner to see pupil
g. Patient looks in distance (at chart)
h. Use bright/small light source (illuminate only one eye at a time!)
i. Part One: Do both pupils move?
• Light starts aiming over the patient’s shoulder, off the right eye
• Aim light directly at right eye
• Move light off right eye to shine back over the patient’s shoulder
• Repeat for left eye

Question 5

Describe swinging flashlight test

Answer 5

j. Part Two: Do both optic nerves work EQUALLY well? (“Relative”)
• Light over right shoulder
• Directly on right eye
• QUICKLY- light on left eye
• QUICKLY - light on right eye
• Compare pupil sizes when light is on each eye

Question 6

Positive Volcano Sign

Answer 6

a. Normal aging: lens continues to make stroma, lens a-p length increases
b. Iris pushed further forward
c. Iris pushed towards cornea
d. Iris may block trabecular meshwork
e. To see if iris is flat or pushed forward:
• Put light parallel to plane of iris
o That is, shine light from temporal side of side of face
• Iris is flat, no shadow (A)
• If iris is pushed forward, shows shadow on nasal edge (B)
• “Like a volcano at sunset”

f. If iris is pushed forward
• Positive volcano sign
• If you dilate that eye, the iris may get pushed directly into the trabecular meshwork, blocking egress of aqueous humor into the meshwork (blocking its flow)
• That’s acute angle-closure glaucoma – That’s bad.
• POSITIVE VOLCANO: DO NOT DILATE PUPILS

Question 7

What to check for during an exam of the optic disc and retina

Answer 7

i. Visualize optic disc: swelling, cupping, color
-CLINICAL EXAMPLE – Papilledema
• Physical description
o Swollen Optic Nerve head
o Margins of Disc obscured
o Fluffy white swelling of nerve fiber layer
o Hemorrhages of nerves at disc

j. Visualize retina: vascular caliber and background
-• Vascular caliber→Systemic hypertension
• Hemorrhages in/beneath retina→Hypertension, Diabetes mellitus
• Retinal ischemia signs→Cotton wool spots, Diabetes mellitus
• Retinal tears/detachments