Reference Ranges of Intraocular Pressure, Central Corneal Thickness, and Ocular Surface Temperature in Van Cats

Objective: To establish reference ranges for intraocular pressure (IOP), central corneal thickness (CCT), and ocular surface temperature (OST) in Van Cats, and to evaluate the effects of sex and eye color on these parameters. Animals Studied: A total of 307 healthy purebred Van Cats (98 males, 209 females) housed at the Van Cat Research Center were examined. Procedures: Ophthalmic measurements were performed between 10:00 a.m. and 5:00 p.m. without sedation. CCT, IOP, and OST were measured using pachymetry, rebound tonometry, and infrared thermography, respectively. Statistical analyses compared variables by eye color and sex, assessed interocular symmetry, and explored correlations among ocular parameters. Results: No significant differences were detected between right and left eyes for IOP, CCT, or OST (p > 0.05). Mean values were: IOP = 24.8 ± 6.8 mmHg, CCT = 649.1 ± 62.2 μm, and OST = 36.25°C ± 0.73°C. Heterochromatic (blue–amber) cats showed slightly higher IOP and CCT than blue–blue cats (p < 0.05). A weak positive correlation was found between IOP and CCT (r = 0.21–0.24, p < 0.01). Sex showed minimal influence, except that males with blue eyes had lower IOP than those with amber eyes (p = 0.01). OST did not differ among groups (p > 0.05). Conclusions: This study establishes breed-specific reference ranges for IOP, CCT, and OST in Van Cats. Eye color and sex exert limited effects, while the breed shows strong bilateral symmetry and stable ocular biometry. These findings provide useful benchmarks for clinical and research applications.