Obtained mydriasis in long-term type 2 diabetic patients

Purpose: The purpose of this study was to evaluate obtained mydriasis and prevalence of small pupil in long-term type 2 diabetic patients. Methods: A prospective observational cross-sectional study was carried out. We included 107 eyes from 107 patients (mean age: 60.8) with long-term (≥10 years) type 2 diabetes mellitus. Patients were divided into 2 groups: no apparent diabetic retinopathy (group 1, n=33) and diabetic retinopathy (group 2, n=74). Exclusion criteria were eyes with prior intraocular surgeries, presence of other ocular disorders that may affect iris, or any other condition that precludes the precise measurement of pupil size. Sixty eyes in 60 age-matched nondiabetic patients (mean age: 61.0) scheduled for routine fundoscopy exam were enrolled as control. We measured pupil diameter by pupil gauges at 40 min after instillation of eye drops (phenylephrine 10% and tropicamide 1%). Small pupil was defined as pupil diameter of 6 mm or less. Results: Mean pupil diameter was 8.07 mm [standard deviation (SD): 0.59 mm] in the control group, 7.46 mm (SD: 0.71 mm) in group 1, and 7.24 mm (SD: 0.83 mm) in group 2. Both group 1 (P<0.001) and group 2 (P<0.001) showed significant difference when compared with the control group. The incidences of small pupil were 1.9% in the control group, 6.1% in group 1, and 13.5% in group 2. When compared with control, group 2 showed significantly higher incidence of small pupil (P=0.023). Conclusions: Long-term diabetic patients showed poorer response to pharmacological mydriasis than nondiabetic patients. Higher prevalence of small pupil size was found in patients with diabetic retinopathy.