Relationship between corneal sensitivity, corneal thickness, corneal diameter, and intraocular pressure in normal cats and cats with congenital glaucoma.

Gillian McLellan // Publications // Mar 09 2018

PubMed ID: 29517120

Author(s): Telle MR, Chen N, Shinsako D, Kiland JA, Oikawa K, Møller Trane R, McLellan GJ. Relationship between corneal sensitivity, corneal thickness, corneal diameter, and intraocular pressure in normal cats and cats with congenital glaucoma. Vet Ophthalmol. 2019 Jan;22(1):4-12. doi: 10.1111/vop.12558. Epub 2018 Mar 8.

Journal: Veterinary Ophthalmology, Volume 22, Issue 1, Jan 2019

OBJECTIVE To determine the effect of feline congenital glaucoma (FCG) on corneal sensitivity, and relationships between corneal sensitivity, central corneal thickness (CT), and corneal diameter (CD).

ANIMALS AND PROCEDURES Corneal sensitivity (estimated by corneal touch threshold [CTT] using Cochet-Bonnet esthesiometry); CT using ultrasonic pachymetry; intraocular pressure (IOP) using rebound tonometry; and maximal horizontal CD were measured in 16 normal and 14 FCG cats, both males and females, aged 7 months-3.5 years. All procedures complied with an Institutional Animal Care and Use Committee-approved protocol. Data were analyzed by linear regression: paired Student’s t tests for between-eye comparisons, and unpaired Student’s t tests for comparisons between groups. Relationships between parameters were evaluated by Pearson correlation coefficients and linear mixed effects modeling. For statistical tests, with the exception of values that were Benjamini-Hochberg adjusted for multiple comparisons, P-values < 0.05 were considered significant.

RESULTS Mean CTT and CT values were lower in FCG eyes relative to normal eyes, but differences were not statistically significant. Mean CD was significantly larger in FCG eyes relative to normal eyes, and there was a significant negative correlation between CD and CTT in FCG (r = -0.8564, corrected P = 0.005). These associations were confirmed in linear mixed effects models.

CONCLUSIONS Eyes with FCG have significantly larger CDs when compared with normal eyes, and larger CDs correlated with decreased corneal sensitivity in this group. Further studies are warranted to explore the effect of buphthalmos and corneal enlargement on corneal sensitivity and innervation in feline subjects with chronic glaucoma.

© 2018 American College of Veterinary Ophthalmologists.