Ocular Examination - Techniques & Diagnostics

Question 1

Name & Function

Answer 1

Transilluminator - produces focused beam of light for eye exam.

Question 2

Oblique Illumination vs. Coaxial Illumination

Answer 2

Oblique: Light comes in @ different angle than your eye -> highlights subtle corneal opacities, depth, contours of ocular structures, etc.
Coaxial: Light comes in as same angle as your eye -> highlights light-obstructing opacities in the eye

Using transilluminator instrument

Tapetum lucidum reflects light & illuminates it; image shows abnormal opacities = cataracts

Question 3

Name & Function

Answer 3

Direct Ophthalmoscope
- use of coaxial illumination to assess both pupils at same time

Set at 0 diopters

Question 4

Use of direct ophthalmoscope for magnified ocular surface exam?

Answer 4

To assess a small surface area of the eye (i.e. a lesion) at high magnification (15-20 diopters)

Question 5

Why is the fundus examined?

Answer 5

• determine cause of vision loss (retinal degeneration, retinal detachment, optic nerve disease)
• search for evidence of systemic diseases that may be manifesting in the retina

Question 6

Describe the basics of the fundic exam using the direct ophthalmoscope.

Answer 6

1. Set lens to 0 diopters and lean into pateint until retina is in focus, then adujust diopter focus wheel PRN – typically 2-3 cm from cornea
2. Use right eye to evaluate Pt’s right eye, and same for left

Question 7

Pros and cons of Direct Ophthalmoscopy

Answer 7

Pros: highly magnified- great for fine detail
Cons: difficult to evaluate entirety of fundus (esp. peripheral); difficult to isolate/localize lesions due to eye movement

Question 8

Differences between monocular indirect versus binocular indirect ophthalmoscopy

Answer 8

Monocular = handheld light source
Binocular = headset (better depth perception, better lesion evaluation, boths hands are free)

Question 9

Basic technique of indirect ophthalmoscopy

Answer 9

1. use of low-level illumination -> the tapetum lucidum provides a lot of reflection!
2. Once tapetal reflection obtained, position indirect lens into patho of light in front of patient’s eye to obtain fundic image
3. Move towards and away from eye until fundus image fills the entire lens; if you see iris or eyelids, distance is incorrect

Question 10

Characteristics of image of indirect ophthalmoscopy

Answer 10

• wide field of view
• virtual image (upside down & reversed; tapetum = dorsal but appears ventral in image)

Question 11

What are the 4 Rules of Indirect Ophthalmoscopy?

Answer 11

1. Work @ arms-distance from patient
2. Direct light beam coaxially
3. Hold lens perpendicularly to light beam
4. Hold lens @ proper distance from patient’s eye (distance varies by lens & diopter strength; maintain hand contact with patient for stability of lens position)

Question 12

1. Retina is best viewed in a ____ room.
2. Use the ____ practical light intensity.
3. Pharmacologic dilation is ideal. However, dilation is contraindicated if concerned about ______ or ________ __________.

Answer 12

1. dark
2. lowest
3. glaucoma (dilation increases IOP) or lens instability

Question 13

What are 3 most common ophthalmic diagnostics used in the clinic?

Answer 13

1. Schirmer tear test (measures tear production)
2. Fluorescein stain (detects corneal ulcers + evaluates nasolacrimal duct patency)
3. Tonometry (measures IOP in mmHg)

Question 14

What are some practice tips for tonometry?

Answer 14