Controlled blood sugar improves the eye's accommodative ability in type-1 diabetes

Purpose To evaluate the impact of blood sugar level on ocular measures, including refractive error (RE), amplitude of accommodation (AoA), and lag of accommodation (LoA), in pre-presbyopes with type-1 diabetes. Method The fasting blood sugar (FBS) and ocular measures of type-1 diabetes patients (age: 14-39 years;n = 30) on insulin treatment was recorded while they fasted on two separate visits, at baseline and 3 months later. The AoA and LoA was measured with the appropriate spectacle correction worn. The Welch'st-test was used for comparison of the baseline measures between the normal FBS <= 7 (n = 10) and higher FBS > 7 (n = 20) patients, and the pairedt-test used to investigate for differences between the baseline and follow-up data in patients with changes in FBS. Results On average, the spectacle correction for the normal FBS group was marginally more myopic (RE: -0.30 +/- 0.67 D vs. +0.18 +/- 1.00 D,p = 0.032), and they showed greater AoA (5.38 +/- 1.08 D vs. 3.68 +/- 1.43 D,p < 0.001) and lower LoA (1.00 +/- 0.30 D vs. 1.30 +/- 0.38 D,p = 0.004) compared with the higher FBS group at baseline. On the follow-up visit attended by 25 patients, the FBS of 15 patients was reduced by an average of 7.0 mmol/L, 8 patients had an average increase of 5.2 mmol/L, while 2 patients recorded no changes relative to the baseline. The patients whose FBS was reduced showed improvement in the mean AoA from 3.78 +/- 1.58 D to 4.88 +/- 1.61 D (p < 0.001) and a reduction in the mean LoA from 1.37 +/- 0.40D to 0.87 +/- 0.19D (p < 0.001), whereas those with deteriorated control of the FBS showed an opposite trend. Conclusions Controlling hyperglycemia improves ocular accommodation in type-1 diabetes.