A Retrospective Study of Corneal Endothelial Dystrophy in Dogs (1991-2014)

PURPOSE

To retrospectively evaluate the clinical data, diagnostic tests, treatments, and outcomes for dogs with corneal endothelial dystrophy (CED) and determine risk factors for CED when compared with a canine reference population.

METHODS

Medical records of 99 dogs (1991-2014) diagnosed with CED at the University of California Davis Veterinary Medical Teaching Hospital were reviewed and compared with 458,680 dogs comprising the general hospital population during the study period. Retrieved data included signalment, examination findings, diagnoses, treatments, and outcomes associated with CED. The exact Pearson χ2 test or exact Kruskal-Wallis test was used to compare parameters between the groups. Progression of corneal edema was assessed using 3 independent Kaplan-Meier curves, identifying clinically significant changes in corneal opacity.

RESULTS

Boston terriers, German wirehaired pointers, and Dachshunds were overrepresented in the CED-affected group, whereas Labradors were underrepresented. Dogs older than 11 years were overrepresented in the CED-affected group, whereas intact dogs were underrepresented. Surgical intervention was performed (n = 11) based on the severity of disease and secondary complications from CED. Median time to progression of corneal edema was 1) 368 days when an at-risk eye initially without edema developed edema at a subsequent visit, 2) 701 days when there was progression from mild to marked corneal edema, and 3) 340 days when there was progression from focal to diffuse corneal edema.

CONCLUSIONS

Many CED-affected dogs progress over months to years without surgical intervention, making dogs with CED a useful model for studying genetic predispositions and development of novel therapeutics for Fuchs endothelial corneal dystrophy.

Comparison of the characteristics in hen and quail corneas as experimental models of refractive surgery

AIM

To compare the histological, morphological and the biophysical measurements between hen and quail corneas, in order to determine which of them were better suited for use as an animal model for research into corneal refractive surgery.

MATERIAL AND METHODS

A study was performed using the biophysical measurements of the cornea (curvature, thickness, refraction, and axial length) of 20 animals (10 hens and 10 quails). The corneas were then prepared for histological analysis under microscopy light.

RESULTS

The analysis showed that both groups have the same number of corneal layers as the human cornea and with an evident Bowman's layer. The thickness of the hen cornea and axial length of the eye, 225.3±18.4μm and 12.8±0.25mm, respectively, were larger than that of the quail (P<.01 and P<.001, respectively). The radius of curvature for the hen central cornea, 3.65±0.08mm, was greater than that for the quail (P<.001), but the refractive power of each cornea was similar. The proportion of total corneal thickness of the hen stroma, 82.6%, was more similar to that of the human than was the quail stroma, 72.5%. Within the hen stroma, the density of keratocytes, 8.57±1.49 per 5,000μm(2), was about half that in the quail stroma (P<.005).

CONCLUSIONS

Because of the large size of the hen cornea, the stromal thickness and proportional similarity of the corneal layers with human cornea, the hen maybe better than the quail as an alternative species suitable for use in studies of corneal refractive surgery.