Common eye diseases for veterinary technicians (Proceedings)


Common eye diseases for veterinary technicians (Proceedings)

Aug 01, 2008

Quick Eye Anatomy Review

1. Eyelids

a. Protection

b. Tear distribution

c. Light limitation

2. Conjunctiva

a. Mucus secretion

b. Lymph tissue

3. Tear film

a. Corneal nutrition

b. Lubrication

c. Defense system

4. Cornea

a. Focusing apparatus

b. Anterior wall of eye

5. Anterior chamber

a. Contains and drains aqueous

6. Aqueous

a. Fluid produced by the ciliary body

b. Maintains intraocular pressure and provides nutrition to intraocular structures

7. Iris/Pupil

a. Vascular tissue

b. Regulates light into the eye

8. Lens

a. Focusing apparatus of the eye

9. Vitreous

a. Clear, gelatinous structure

10. Retina

a. 10 cell layers of conduction tissue to transmit light images to the brain

11. Optic Nerve

a. An extension of the brain, allows transmission of images to the brain

Common Ocular Diseases

1. Keratoconjunctivitis sicca (KCS, dry eye)

a. Poor tear production or quality

b. Breed predisposition: shi tzu, cocker spaniel, pug, boston terrier, westie, bulldog etc.

c. Normal tear production is 15-25 mm in 60 seconds

d. Permanent disease, controllable, but not curable—medications must be used lifelong!!

e. Tear stimulant therapy: Tacrolimus or cyclosporine

f. Anti-inflammatory therapy: neopolydex

g. Tear substitutes: Genteal gel

h. Can be blinding if left untreated, or result in perforating ulcers

2. Corneal erosions or ulcers

a. Wound of varying depth in the cornea, can be superficial or deep

b. Most corneal nerves are superficial, so these can be the most uncomfortable

c. The underlying cause needs to be addressed in order for the ulcer to heal

d. Surgical options for patients over 50% depth

e. E-collar is important!

3. Glaucoma

a. Elevation in intraocular pressure (15-25 mmHg is normal)

b. Breed predisposition: cocker spaniel, basset hound, Alaskan breeds, chow chow, shar pei, shi tzu, boston terrier, etc

c. Sink analogy: faucets produce fluid in the eye and it is the drain that clogs.

d. If a primary glaucoma it will ALWAYS affect both eyes eventually

e. With preventative treatment in the unaffected eye you can delay the onset of glaucoma 4-fold