The Influence of Type 1 Diabetes Mellitus on Amplitude of Accommodation

Purpose: The aim of the study was to assess the amplitude of accommodation (AA) in patients with type 1 diabetes mellitus (DM) and without diabetic retinopathy. Materials and Methods: In two age- and sex-matched groups - one with twenty-nine eyes of 29 patients with type 1 DM, the other with twenty-nine eyes of 29 healthy individuals - retinal nerve fibre layer thickness and macular volume were determined by using optic coherence tomography in all quadrants, whereas AA was measured with the minus lens technique. The mean values of all three measurements were compared between the groups, and the effect of age, disease duration, (HbA1c and fasting blood glucose on AA were analysed using multiple regression analysis. Results: On average, participants were 25.0 +/- 3.3 years old (range 19-30) in both groups (P = 1.000), and patients had type 1 DM for an average of 13.0 +/- 3.3 years. Mean AA in the right eye was 7.3 +/- 1.1 D among patients and 8.1 +/- 1.1 D among controls (P = .005), as well as significantly negatively correlated with age in both groups (r = -0.735, P <.001 and r = -0.819, P < .001, respectively) and disease duration among patients (r = -0.434, P = .019). In multivariable regression, age and disease duration significantly affected AA in patients, with an R-2 value of 0.623 (P < .001 and P = .025, respectively). Average RNFL thickness was significantly different between the groups (P = .014). Mean macular volumes for areas 1, 3 or 5 mm in diameter were similar between the groups. Conclusions: AA was significantly lower among patients with type 1 DM than among healthy individuals, which suggests that the former might experience presbyopia earlier in life than the general population.