Evaluation of Ocular Biometric and Optical Coherence Tomography Parameters in Preterm Children Without Retinopathy of Prematurity

Abstract

Purpose: To evaluate and compare biometric and optical coherence tomography parameters of ocular structures in preterm children without retinopathy of prematurity with term children.

Methods: A cross-sectional, comparative study was carried out from 2018 to 2019. In this study, 124 eyes of 62 preterm children were compared with 132 eyes of 66 term children aged between 7 and 9 years. Preterm children were born at 28 to 32 weeks with a birth weight of less than 2 kg with no ocular abnormalities, and term children were delivered at 37 or greater weeks and had a birth weight of 2 kg or more. All children had standardized eye examinations, and ocular measurements using the anterior and posterior segment optical coherence tomography and laser interferometry.

Results: Significant differences were found between the term and preterm children for horizontal corneal diameter: median, 12.2 mm (interquartile range [IQR], 0.4) versus median, 12.1 mm (IQR, 0.6; P < 0.005); axial length median, 23.03 mm (IQR, 1.10 mm) versus median, 22.88 mm (IQR, 1.35 mm; P = 0.017); global retinal nerve fiber layer thickness: mean ± standard deviation, 106.54 ± 10.23 µm versus mean ± standard deviation, 103.65 ± 10.178 µm (P = 0.024); temporal retinal nerve fiber layer thickness: median, 76 µm (IQR, 16 µm) vs median, 74 µm (IQR, 14 µm; P = 0.012); and the angle opening distance at 750 µm nasal: mean ± standard deviation, 0.815 ± 0.23 mm vs mean ± standard deviation, 0.749 ± 0.21 mm (P = 0.016). No significant differences were found for other anterior segment and angle parameters.

Conclusions: Preterm children with no retinopathy of prematurity have smaller eyes and thinner retinal nerve fiber layers than their term counterparts. The long-term effects of interrupted ocular growth in preterm children should be further studied into adulthood.

Translational relevance: Preterm children maybe more predisposed to certain eye conditions because they have smaller eyes, and thus should be further monitored clinically.

Figure 1.

Measurement of the CCT, anterior lens vault (LV), and nasal and temporal angles. The caliper is placed on both nasal and temporal scleral spurs and anterior LV is measured as the part of the lens above the connecting line. Automated angle assessment done using calipers placed on the scleral spur. SS, scleral spur. (A, B) Scleral spur iris end point. (C) AOD500 corneal end point. (D) AOD500 iris end point. (E) AOD750 corneal end point. (F) AOD750 iris end point.

Figure 2.

Definitions of the Iridocorneal angle measurements. Reprinted with permission from Visante OCT Model 1000 System Software Version 3.0 User Manual. AOD500, distance between C and D; AOD750, distance between E and F; TISA500, area of the polygon formed by A, C, D, and B; TISA750, area of the polygon formed by A, E, F, and B.