Abstract
Purpose: :
It is generally agreed that diabetic patients have reduced corneal sensitivities as part of a global poly-neuropathy, and if severe enough, the condition may become manifest as diabetic keratopathy. The literature, however, is full of conflicting reports with regards to predictive factors such as duration of disease and degree of retinopathy. We therefore sought to evaluate the corneal sensitivities of a cohort of diabetic patients at our institution to determine whether there is a relationship between the degree of corneal hypoesthesia and various measures of diabetes severity with the hypothesis that decreased corneal sensitivity is a function of the duration and severity of diabetes compounded by a history of pan-retinal photocoagulation.
Methods: :
Asymptomatic diabetic patient and control patients all without a history of corneal surgery or disease were evaluated with the Cochet-Bonnet aesthesiometer. Additionally, the subjects answered a brief questionnaire regarding the duration and severity of diabetes, insulin usage, and the presence or absence of peripheral neuropathy. A chart review was also conducted on the same subjects to determine the degree of retinopathy and whether they have had retinal laser treatments.
Results: :
172 subjects were tested (100 controls and 72 diabetics). There were no significant differences between the age, sex, and ethnicity of the two groups. Diabetics as a group had decreased corneal sensations (p < 0.005). The duration of diabetes and background diabetic retinopathy were not statistically-significant predictors of corneal hypoesthesia. Peripheral neuropathy (p = 0.001), insulin usage (p = 0.001), proliferative diabetic retinopathy (p = 0.006), and a history of pan-retinal photocoagulation (p = 0.003) were statistically significant predictors of corneal hypoesthesia.
Conclusions: :
The duration of diabetes did not correlate with corneal hypoesthesia, but the severity of diabetes as manifest by the presence of peripheral neuropathy, insulin usage, and proliferative retinal disease strongly correlated with corneal hypoesthesia. A history of pan-retinal photocoagulation was additionally correlated with corneal hypoesthesia.
Keywords: cornea: clinical science • diabetes • clinical (human) or epidemiologic studies: risk factor assessment