Poorly controlled type 1 diabetes (T1D) without diabetic retinopathy affects multiple anterior segment parameters, which should be regularly evaluated during routine follow-up, according to research published in Photodiagnosis and Photodynamic Therapy. 

Researchers conducted a prospective, observational, cross-sectional study to determine the role that abnormal glucose metabolism plays on the cornea, anterior chamber depth, and volume in a population of children with poorly controlled T1D without diabetic retinopathy compared with healthy controls. 

Investigators evaluated 60 pediatric patients (36.7% girls; mean age, 11.2 years ± 3.1 years) with poorly controlled T1D (HbA1c >7.0%) and 30 control patients (53.3% girls; mean age, 9.6 years ± 2.8 years) with a full ophthalmologic exam and corneal tomography. No signs of nephropathy or retinopathy were present. Mean T1D duration was 6.3 years (± 1.4 years) and mean HbA1c in the T1D group was 9.59% (± 1.6%; range, 7.1% to 13.6%) compared with 5.90% (± 0.2%; range, 4.7% to 5.9%) in the control group. 

Anterior segment parameters were compared between groups. No statistically significant differences in curvature parameters, including keratometry (K) max, K mean front, radius (R) min front, and R min back were noted. However, the 2 groups were statistically significantly different in terms of central corneal thickness (564.36 μm ± 26.5 μm vs 534.27 μm ± 33.20 μm), corneal volume, (61.84 mm3 ± 2.90 mm3 vs 59.57 mm3 ± 3.00 mm3), anterior chamber depth (3.09 mm ± 0.20 mm vs 3.10 mm ± 0.30 mm), mean lens density (8.55% ± 2.50% vs 7.76% ± 0.30%), lens density standard deviation (2.42% ± 2.20% vs 1.60% ± 0.90%), and maximum lens density (52.65% ± 25.30% vs 47.23% ± 15.60%); endothelial cell density, anterior chamber volume, and pupil diameter were similar.


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Investigators also identified a positive correlation between HbA1c values and mean lens density, lens density standard deviation, corneal volume, and central corneal thickness in the T1D group (R=0.47, 0.34, 0.36, and 0.39, respectively). Study limitations include the lack of measurements of anterior segment parameters from children with well-controlled T1D without diabetic retinopathy. 

“When children with poorly-controlled T1D without diabetic retinopathy were compared with healthy children, there were changes in the cornea, anterior chamber, and lens, which were attributed to poorly controlled [diabetes],” the researchers concluded. “These anterior segment parameters can be used in routine…follow-up of patients with [diabetes]. Regular follow-up of patients with T1D, particularly of those with poorly-controlled T1D, is recommended and should include Pentacam corneal tomography.” 

Reference

Karahan M, Demirtas AA, Erdem S, et al. Evaluation of anterior segment parameters with Pentacam in children with poorly-controlled type 1 diabetes mellitus without diabetic retinopathy. Photodiagnosis Photodyn Ther. Published online February 5, 2021. doi: 10.1016/j.pdpdt.2021.102206