The Cross-Sectional Case-Control Integrated Analysis of Vitreous Chamber Length, Corneal Volume, and Globe Biometry in Pediatric Beta-Thalassemia Major

Abstract

Objective: To determine ocular changes, particularly in vitreous chamber length (VCL) and corneal volume (CV), analyze globe biometric features in emmetrope pediatric beta-thalassemia major ( ?- TM) patients using Cirrus topography and IOLMaster devices, and com- pare the results to age- and gender-matched healthy individuals. Material and Methods: This cross-sectional case-control study in- cluded 36 multi-transfused ?-TM patients (Group 1, 72 eyes) with a mean age of 9.18±3.14 years and no other hemoglobinopathies or ane- mias unrelated to ?-TM. A control group (Group 2, 72 eyes) included 36 healthy children who had routine ophthalmology exams. A comprehen- sive ophthalmologic exam was performed, including auto-refraction, best-corrected visual acuity, and intraocular pressure (IOP), followed by dilated slit-lamp biomicroscopy. The corneal topography and globe biometric evaluation were followed by a pair-wise data comparison.Re- sults: The axial length (AL) (22.58±0.64 vs 23.06±0.71 mm), VCL (15.48±0.68 vs 15.92±0.69 mm), CV (55.47±2.95 vs 57.65±2.83 mm3), IOP (12.68±2.34 vs 11.08±1.68 mmHg), keratometry values (K1, K2, Kmean, Kapex), as well as central corneal thickness (523.00±28.41 vs 547.29±26.45 ?m), were all significantly different between groups 1 and 2, respectively (p<0.05). There were no significant differences in ante- rior chamber depth and volume, iridocorneal angle, horizontal visible iris diameter, horizontal anterior chamber diameter, and crystalline lens thickness (p>0.05). Conclusion: ?-TM patients appear to have signifi- cant ocular growth retardation than relatively age-matched healthy chil- dren, as demonstrated by shorter AL and VCL, as well as lower CV. This circumstance could have prompted compensatory biometric mod- ifications, as evidenced by a relatively steeper cornea and thicker crys- talline lens, to accomplish emmetropization.