How to make the most of your ophthalmic examination (Proceedings)

ADVERTISEMENT

How to make the most of your ophthalmic examination (Proceedings)

source-image
Oct 01, 2008

Objectives

• How to perform an organized exam

• Diagnostic procedures

o STT

o Culture, cytology

o Staining

o Tonometry

• Direct and indirect ophthalmoscopy

So, where to start...?

• Thorough history

• Signalment

• Primary complaint

• Current treatment if any

• Concurrent disease, attitude, appetite, etc.

• Travel history

Observation from a Distance

• Watch the patient enter the exam room and move about obstacles in the room

• If vision loss is suggested by history, consider maze/obstacle course testing in both light and dim/dark conditions

• Evaluate the face for symmetry and note any signs of lameness, which may relate to underlying systemic disease

Restraint

• Small animals can generally be manually restrained either in a corner or on a table

• Muzzles and towels can be used with fractious patients

• Equine patients usually require sedation and local nerve blocks

• Cattle can be examined in a head chute

• Exotics can be held or sedated

Beginning the Exam

• Observe the face and eyes for symmetry, evaluate palpebral reflex, menace response, retropulse the globes and palpate the orbits

• Evaluate pupils in light and dark, perform PLrs, swinging flashlight test, and dazzle

• Get an overall picture of the lids, cornea and conjunctiva to decide on diagnostics

Initial Diagnostics – STT

• Perform Schirmer Tear Test first

• STT1

• Measures basal, residual, and reflex tears

• Strip is placed in the ventral conjunctival fornix for one minute

• Dog (19.8 ± 5.3 mm/min), Cat (16.9 ± 5.7), Horse and cow (>15), Rabbit (5.3 ± 2.9)

Culture and Cytology

• If indicated, culture and/or cytologly of the cornea or conjunctive should be performed next, before adding any drops to the eye

• Most topical ophthalmic preparations contain preservatives that may inhibit bacterial growth, thereby affecting cultures

• Cultures can be obtainined with moistened swabs, and cytology with a swab, spatula, cytobrush, or scalpel blade (blunt end)

Vital Stains

• Sodium Flourescein

o Absorption spectrum peaks at 490nm (blue light)

o Flourescence at 520nm (green light)

o Used to detect corneal and conjunctival epithelial defects, preocular tear film deficiencies 9TFBT), NL duct patency (Jones test), leakage of aqueous from corneal wounds (Seidel test)

• Rose Bengal

o Used to detect preocular tear film disorders, mucin preocular film deficiencies, superficial corneal epithelial abnormalities