Parker County Today August 2017 - Page 88

our expertise: VET COLUMN All Creatures Great &Greater BY TOM HUTCHINS, DVM, DABVP 86 Equine corneal ulceration is a sight- threatening disease requiring early clinical diagnosis, laboratory confirmation, and appropriate medical, and/or surgical therapy. Both bacterial and fungal keratitis (inflammation of the cornea) may present with a mild, early clinical course, but require prompt therapy if serious eye complications are to be avoided. Ulcers can range from simple, superficial breaks or abrasions in the corneal surface, to full- thickness corneal perforations with prolapse of the iris (the colored portion of the eye). The thickness of the cornea is only 1.0–1.5 millimeters (mm). The normal equine cornea is 8-10 cell layers thick but increases to 10- 15 layers thick with inflammation of the basal cells following corneal injury. The basement membrane is not completely formed 6 weeks following corneal injury in the horse, in spite of the corneal epithelium (surface cells) covering the ulcer site. Healing time of a 7mm-diameter ulcer that is only partial thickness can take up to 2 weeks to heal if there is no bacterial infection associated with the ulcer. The environment of the horse is such that the cornea and the inside of the eyelids are constant ǒW6VBF&7FW&@gVv&v626R66W6W0b6&VV6W&F6FRg&G&V&P7F667W27G&WF667W26WVF27W&vW2BgW6&V7V6W2FR6&VWFVƗV2f&֖F&R&'&W"FFRf6b&7FW&BgVvFVfV7BFRFV"fЦ"6&VWFVƗVw2&7FW&"gVvFFW&RFFR6&VBFFFRfV7FWFVƖFVfV7G2VVBB&RgVF6W7206&V2vF'FF6W72FVfV7G2&R&P7W66WF&RFFW&V6R'6W'F&v60G"FWF60F&R6&V2FB&RgVǒF7BFW&R&R6W'F6V26R&7FW&@gVvvFFRFV"fFB6FvǐFW7G'V7FfRV秖W2FB6&W7VB&@6&VFrBW&f&FFR'6RW6W76fRV秖R7FfG2FW&VB( VF~( ЦB&W7VG2vVFW2V&6RbFP6&VFF6&VV6W&FVFFVǐ&WV&W2FRFVw&FFb6vVv6f&2FRg&Wv&bFR6&VFW&R2&fVvVWF2&VF76FF6&VV6W&FFR'6R'WBFRVVP6&VVƖr&W'FW2bFR'6R&Vv&@FW6W76fR6&Vf67V&FBf'&60V"F&R7G&vǒ7V6W27V6f2vW0B'&VVG2b'6W2GW2bVf&VG0&RB&6FR6Ɩ66v2bV&ǒV6W&F&Rf66VFW72bFR6&V&VFW72`FR66W&vFR'BbFRWRBFV7G&FVB'67FB67W&RbFRWRGvF6rbFRWVƖG2BW6W76fRFV&p&RW7Vǒ&W6VB2vVvF6V6W'2FRWW"WVƖBG&6ƖvFǒB@&RgVǒ66VB6v2bFW&"WfVF2 fFbFR6&W"W7B6FRF