Fasting Plasma Sugar: A Predictor of Accommodative Function in Diabetes

BCLA CLEAR Presbyopia: Epidemiology and impact

The global all-ages prevalence of epidemiologically-measured 'functional' presbyopia was estimated at 24.9% in 2015, affecting 1.8 billion people. This prevalence was projected to stabilise at 24.1% in 2030 due to increasing myopia, but to affect more people (2.1 billion) due to population dynamics. Factors affecting the prevalence of presbyopia include age, geographic location, urban versus rural location, sex, and, to a lesser extent, socioeconomic status, literacy and education, health literacy and inequality. Risk factors for early onset of presbyopia included environmental factors, nutrition, near demands, refractive error, accommodative dysfunction, medications, certain health conditions and sleep. Presbyopia was found to impact on quality-of-life, in particular quality of vision, labour force participation, work productivity and financial burden, mental health, social wellbeing and physical health. Current understanding makes it clear that presbyopia is a very common age-related condition that has significant impacts on both patient-reported outcome measures and economics. However, there are complexities in defining presbyopia for epidemiological and impact studies. Standardisation of definitions will assist future synthesis, pattern analysis and sense-making between studies.

Accommodative disorders in non-presbyopic subjects with type 1 diabetes without retinopathy: A comparative, cross-sectional study

PURPOSE

The purpose of this study was to assess accommodative function in non-presbyopic individuals diagnosed with type 1 diabetes (T1D) without any signs of retinopathy, to determine the existence of possible accommodative disorders related to this disease, and to determine the influence of T1D duration and glycosylated haemoglobin values on accommodative function.

METHODS

This comparative, cross-sectional study included 60 participants between 11 and 39 years old, 30 with T1D and 30 controls, with no previous eye surgery, ocular disease or medication that could affect the results of the visual examination. Amplitude of accommodation (AA), negative and positive relative accommodation (NRA and PRA), accommodative response (AR) and accommodative facility (AF) were assessed using the tests that showed the highest repeatability. Participants were classified based on normative values into 'insufficiency, excess or normal results', and a diagnosis of accommodative disorders (accommodative insufficiency, accommodative infacility and accommodative excess) was made.

RESULTS

Participants with T1D had statistically significant lower AA and AF and higher NRA values than the controls. Furthermore, AA was significantly and inversely correlated with age and the duration of diabetes; however, AF and NRA were only correlated with disease duration. In the classification by accommodative variables, a higher percentage of 'insufficiency values' was observed in the T1D group (50%) than in the control group (6%; p < 0.001). In terms of accommodative disorders, accommodative infacility was the most prevalent (15%), followed by accommodative insufficiency (10%).

CONCLUSIONS

Our findings indicate that T1D affects most accommodative parameters, with accommodative insufficiency being associated with this disease.

Vision-related symptoms, accommodative and binocular vision performance in young diabetics vs. normal controls

PURPOSE

To compare accommodative and binocular vision performance between young diabetic subjects and normal controls, and to investigate the correlation of accommodative/binocular indices with the severity of diabetes.

METHODS

Thirty young subjects with diabetes mellitus (DM) and 30 age-matched normal controls were recruited in this hospital-based cross-sectional study. DM was diagnosed by a haemoglobin A1c (HbA1c) higher than 6.5%. The status of vision-related symptoms was examined by the convergence insufficiency symptoms survey (CISS). All participants underwent a complete optometric examination including visual acuity measurement, objective and subjective refraction, accommodative and binocular vision assessments.

RESULTS

All study participants were between 18 and 40 years of age. There were no statistically significant differences in best-corrected visual acuity (BCVA), sphere, cylinder and spherical equivalent refraction (SE) between the diabetes and control groups. The median near point of convergence (NPC) was significantly more remote in diabetics compared with the control group. Mean accommodative amplitude (AA) and vergence facility (VF) and the median monocular accommodative facility (AF) were significantly lower in diabetic subjects compared with normal controls. In addition, the median accommodative lag in the diabetic group was significantly higher than the control group. A significantly higher percentage of the diabetic group were symptomatic (26.6%), compared with the controls (6.6%). The NPC and accommodative lag showed a significant positive correlation with the HbA1c level, while VF, AA and AF exhibited a significant negative correlation with HbA1c.

CONCLUSION

Aspects of accommodative and binocular vision performance are strongly affected by DM. There is also a significant correlation between accommodative and binocular disorders with the severity of DM. A significant percentage of young subjects with DM have severe vision-related symptoms.

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's t-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 paired t-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.

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.