Introduction: Diabetes mellitus leads to microvascular complications and altered basement membranes, which are partly responsible for ocular complications. Corneal nerve impairment is involved in ocular surface disease as well. We examined the possible relation between ocular surface signs and retinal or neuronal degenerative complications due to diabetes.
Patients and methods: Diabetics and control subjects were compared for corneal sensitivity and tear function parameters such as the Schirmer test, tear film break-up time (BUT), and fluorescein and lissamine green stainings. The relation of the duration of the disease, the stage of retinopathy, metabolic control (HbA1c), and diabetic peripheral neuropathy with ocular surface disorders were noted.
Results: Twelve healthy patients were compared to 48 diabetics. The Schirmer test value, BUT, and fluorescein and lissamine green impregnations were significantly modified in diabetics compared to controls (p<0.0001), with no relation to the duration of the disease or metabolic control. The mean corneal sensitivity was significantly lower in diabetic patients (p<0.01), diabetics with peripheral neuropathy (p=0.00008), and diabetics with preproliferative retinopathy (p=0.0003). Tear function parameters were more frequently altered in patients presenting preproliferative retinopathy and peripheral neuropathy (p<0.001).
Conclusions: Diabetes can lead to ocular surface impairments with qualitative and quantitative tear disorders, all of which seem to evolve in close relation with retinopathy and peripheral neuropathy. These lacrymal and corneoconjunctival abnormalities, even if not currently mentioned by diabetic patients, can result in severe neurotrophic complications.