Corneal biochemical features of patients with vernal keratoconjunctivitis.

Background: Vernal keratoconjunctivitis (VKC) is a chronic, bilateral, seasonally exacerbated, allergic inflammation of the ocular surface, involving bulbar and ⁄ or tarsal conjunctiva and cornea. The ocular response analyzer (ORA) measures corneal biomechanical properties in vivo by monitoring and analyzing the corneal behavior when its structure is submitted to a force induced by an air jet. This study was designed to examine corneal biomechanical properties and intraocular pressure in patients with VKC, and to compare with control eyes.

Methods: ORA measurements were performed on the both eyes of 26 patients with VKC (group I) and 14 healthy children who served as the control group (group II). Corneal hysteresis (CH), corneal resistance factor (CRF) and intraocular pressure [Goldmann correlated (IOPg) and corneal compensated (IOPcc)] were recorded with ORA.

Results: Mean age of patients with VKC and control groups were 11.3 ± 5.8 and 10.6 ± 1.9 years for groups I and II respectively. Mean (± SD) of the CH and CRF readings were 10.1 ± 1.6 versus 10.5 ± 1.6 (p > 0.05) and 9.5 ± 1.7 versus 10.8 ± 1.7 mmHg (p < 0.05), in groups I and II respectively. Mean (± SD) of the IOPg and IOPcc recordings were 13.3 ± 3.4 versus 16.6 ± 3.6 mmHg (p < 0.05) and 14.3 ± 3.4 versus 16.9 ± 3.7 mmHg (p > 0.05) in groups I and II respectively. Statistical analysis revealed significant differences for CRF and IOPg between the study groups.

Conclusion: The mean CRF and IOPg values of patients with VKC were lower than those of controls. According to the results of our study, one can conclude that corneal biomechanical property, CRF, could be different in VKC patients compared to normals.