Ulcerative keratitis is a common and potentially blinding ocular disease of horses, capable of progressing to corneal perforation in as little as 24 h. This rapid stromal degeneration is mediated in part by exogenous and endogenous proteinases. We measured and compared the concentrations of two matrix metalloproteinases (MMP-2 and MMP-9) and a serine proteinase (neutrophil elastase) present in the precorneal tear film of normal horses and horses with rapidly progressing ulcerative keratitis. Precorneal tear film samples were collected from 23 ulcerated and 21 unaffected eyes of 23 horses with unilateral ulcerative keratitis, and from 33 normal eyes of 17 control horses. MMP-2, MMP-9, and neutrophil elastase were identified by casein and gelatin zymography and quantified by computerized image analysis. Median MMP-9 levels were significantly higher in the precorneal tear film of young control horses vs. older control horses (P = 0.005). Median MMP-2, MMP-9, and neutrophil elastase levels were significantly higher in the precorneal tear film of ulcerated eyes when compared to age-matched normal controls (P = 0.004, P = 0.001, and P = 0.012, respectively). Median MMP-2 levels were also significantly higher in the precorneal tear film of contralateral eyes of affected horses when compared to age-matched normal controls (P = 0.004). No significant differences in median proteinase levels were detected between 'sterile' ulcers and those from which bacteria or mixed infections (bacteria and fungi) were isolated. However, median MMP-2 and neutrophil elastase levels were significantly higher in the precorneal tear film of eyes with 'sterile' ulcers when compared with ulcerated eyes from which fungi were isolated (P < 0.05). The results of this study support the use of topical antiproteinase therapy which targets both MMPs and serine proteinases in progressive equine ulcerative keratitis.

A young dog was presented with rapidly progressive, unilateral, exophthalmos. Ultrasound-guided fine-needle aspiration of the retrobulbar mass resulted in a diagnosis of fibrosarcoma. Magnetic resonance imagery revealed tumor invasion into the brain, and palliative therapy was elected. The dog was euthanized 4 weeks following diagnosis due to progressive neurological signs. The final diagnosis was neurofibrosarcoma involving the pons, brainstem, left orbit and left trigeminal nerve.

The objective of the research was to compare the efficacy of Optisol-GS (OGS, Bausch & Lomb Surgical, Irvine, CA, USA) with triple antibiotic ophthalmic solution (neomycin-polymyxin B-gramicidin, NPG; Bausch & Lomb, Tampa, FL, USA) in preserving the viability of corneal endothelial cells. The study subjects were thirty young to middle-aged dogs with no gross corneal pathology that had been euthanized by pentobarbital overdose for reasons unrelated to this project. Corneal tissues were harvested, analyzed, and randomly assigned to treatment groups: one of two media (OGS or NPG), and one of five storage times (1, 7, 14, 21, or 35 days). Six corneas were stored in each medium for each time period. Corneal endothelial cell viability was evaluated pre- and poststorage by vital staining (trypan blue and alizarin red S), and endothelial cell morphology was evaluated with scanning electron microscopy. Storage in NPG caused significant loss (100%) of endothelial cells after all storage times. OGS storage maintained a high level of endothelial cell viability up to 21 days (98.9% +/- 1.3% viability). A significant decrease in percentage viability was also found for OGS-stored corneas between 21 and 35 days, when endothelial cell viability decreased to 61.4% +/- 45.9%. The conclusions are that NPG storage at -20 degrees C is a very poor choice of media for corneal tissue banking if graft clarity is the goal. Storage in Optisol-GS at 4 degrees C for up to 21 days resulted in significantly higher percentages of viable endothelial cells. Optisol-GS storage should facilitate corneal preservation for canine keratoplasty patients.