Aims To determine longitudinal differences in foveal thickness in preschool-aged patients with or without a history of type I retinopathy of prematurity (ROP).

Methods A study of 201 eyes, including 32 laser±intravitreal bevacizumab (IVB)-treated eyes, 37 IVB-treated eyes, 14 spontaneously regressed ROP eyes, and 118 age-matched controls were enrolled in this study. The retinal thicknesses (full, inner and outer) were measured in the foveal area at 6-month intervals four consecutive times by optical coherence tomography.

Results The foveal thicknesses among the four groups were similar at all four visits (all p>0.05) after gestational age (GA) adjustment and remained similar with no differences after the full retinal thickness was divided into inner and outer thicknesses (all p>0.05). The full and outer foveal thicknesses of premature children increased over time (0.17 μm/month and 0.17 μm/month; p=0.0001 and 0.0003, respectively), but the inner foveal thickness remained unchanged with time (0.002 μm/month; p=0.09). Moreover, the positive correlation with best-corrected visual acuity was stronger for outer foveal thickness than for inner foveal thickness (γ=0.281, p<0.0001 and γ=0.181, p<0.0001, respectively).

Conclusion The thickness of fovea in laser±IVB-treated, IVB-treated, regressed ROP and preterm eyes showed no difference after GA adjustment. The whole and outer foveal thicknesses increased with time in preschool-aged children over a 1.5-year follow-up period, but the inner foveal thickness remained unchanged with time.