Corneal Sensitivity In Patients Treated For Glaucoma Or Ocular Hypertension

Abstract

Purpose: : To evaluate the corneal sensitivity in patients treated with intraocular pressure-lowering medications

Methods: : Thirty nine patients treated for glaucoma or ocular hypertension (OHT) and 9 untreated patients were included in this study. Patients treated with intraocular pressure-lowering medications were divided in 3 groups according to the number of instillations of preserved eyedrops (0, 1 and ≥ 2). Corneal sensitivity was assessed using the Cochet-Bonnet esthesiometer. Then, all patients underwent a complete examination of the ocular surface including Schirmer test, tear film breakup time (TBUT) and, corneal and conjunctival fluorescein staining. The Ocular Surface Disease Index (OSDI) questionnaire was used to evaluate symptoms.

Results: : The corneal sensitivity was 58.8 ± 2.8 mm, 56.2 ± 5.2 mm, 50.3 ± 12.5 mm and 44.3 ± 13.6 mm in untreated patients, in patients treated with 0, 1 and ≥ 2 instillations of preserved eyedrops, respectively. The corneal sensitivity of patients treated with preserved eye drops was significantly lower as compared to untreated patients (p < 0.001) and patients treated with preservative-free eyedrops (p = 0.012). The corneal sensitivity of patients treated with intraocular pressure-lowering medications was negatively correlated to the number of instillations of preserved eyedrops (r = -0.390; p < 0.001) as well as to the duration of treatment (r = - 0.357; p = 0.001).

Conclusions: : The chronic administration of eyedrops containing preservatives may decrease corneal sensitivity. These results could explain the absence of correlation between symptoms and signs sometimes observed in patients treated for glaucoma or OHT.

Keywords: cornea: tears/tear film/dry eye • ocular irritants