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AIM: To compare anterior segment parameters between two groups of type 2 diabetic with and without diabetic retinopathy (DR) and non-diabetic elderly subjects based on hemoglobin A1c (HbA1c) levels and status of DR. METHODS: This study was conducted on 997 residents aged 60y or over in Tehran, Iran. Diabetic group had HbA1c level ≥6.4% with no other systemic problems. The non-diabetic participants had normal eye findings and no systemic diseases. K1, K2, mean K, Q-value, anterior, central, posterior, and total corneal densitometric findings, anterior chamber volume (ACV), anterior chamber depth (ACD), corneal volume (CV), and pachymetry were measured by Pentacam AXL. RESULTS: A total of 678 non-diabetic (39% male) and 319 diabetic (35% male) subjects with mean age of 66.31±5.23 and 67.22±4.96y were examined, respectively. No statistically significant difference was found in anterior segment parameters between non-diabetic and diabetic groups (all P>0.05). However, middle, posterior, and total corneal densitometric values were statistically different between two groups after controlling the effects of confounders (P=0.014, 0.007, and 0.042, respectively). Corneal densitometric values in all layers, ACD, and ACV were different between diabetic subjects with and without DR (all P<0.05). In the diabetic group, only corneal densitometric values had a negative relationship with fasting blood sugar (P<0.001). ACD and ACV had a negative correlation with HbA1c levels (all P<0.05, r=-0.129 and -0.146, respectively). However, the relationships were not observed after controlling the confounders (P=0.938, 0.466, respectively). CONCLUSION: Considering the higher densitometric values of the cornea and lower ACD and ACV in diabetic subjects with DR, it is suggested that the examiners should perform comprehensive retinal examinations when faced with such conditions.

Background and Objectives: We aimed to investigate the variation of heterophoria during a day in students with a normal visual system. Methods: This cross-sectional observational study was conducted on 15 students aged 19 to 22 years with 20/20 visual acuity and normal binocular vision. Heterophoria was measured with a prism bar and alternate cover test at near and far distances (40 cm and 6 m). The measurement was performed from 8 to 10 PM in one day with 2 hours intervals. Results: The Mean±SD age of students was 21.6±0.87 years (63% women and 37% men). The mean deviation in far and near order was 1.93 and 3.75 prism diopter, respectively. The Greenhouse-Geisser test concluded no significant difference between the measurements of distant heterophoria during the day (F=1.362, df=3.066, P=0.267). However, the near-distance results were significant (F=15.17, df=7, P˂0.05). The paired t-test results showed that the highest amount of exophoria was observed near 4 PM, which was significantly different from the initial value, and the difference increases at the end of the day so that the mean difference of the initial near exophoria value from 4 to 10 PM reached from -1.254 to -3.508. Conclusion: Changes in refractive error or high order aberration increase near work and decrease the illumination during a day can induce force on accommodation and vergence. So, at the end of the day, the exophoria increases. Thus, it is preferable to perform eye examinations at the end of the day to make more accurate decisions about the diagnosis and treatment of patients.

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