Corneal sensitivity decreases with age, study finds

Corneal sensitivity decreases gradually with age in both diabetic and nondiabetic patients, while the threshold of sensitivity shows increasing variation, according to a study. No relationship was found between corneal sensitivity and the time since diabetes diagnosis, indicating that the corneal innervation is affected by the abnormal glucose metabolism in patients with diabetes, according to the study’s authors.

Paul J. Murphy and colleagues at Cardiff University in Wales and other institutions tested the corneal sensitivities of diabetic and nondiabetic patients using a noncontact corneal aesthesiometer. To assess the effect of age and diabetes on corneal sensitivity, they divided 116 subjects without diabetes and 111 subjects with diabetes into three groups: young (29 years old or younger), middle (30 to 59 years old) and older (older than 60). Exclusion criteria included severe retinopathy or a history of conditions known to affect corneal sensitivity. The right eye of each subject underwent corneal sensitivity threshold testing.

A gradual loss of sensitivity occurred with increasing age, the researchers found. In the group without diabetes, inter-age-group comparisons found significant differences between the cooling thresholds for the three age groups. For those with diabetes, a significant difference was found between the middle and older groups only. No relationship was found between duration of disease and corneal sensitivity, nor was there a sex-based difference, in either type 1 or type 2 diabetes.

The study is published in the June issue of Investigative Ophthalmology & Visual Science.