[Ocular biometry of infants and young children with congenital cataract]

Objective: To understand the developmental characteristics of early ocular biological parameters in patients with congenital cataract. Methods: Retrospective case series study. The ocular biometry data such as the axial length, corneal curvature, anterior chamber depth and central corneal thickness of 169 patients under 3 years old who were diagnosed with congenital cataract in Eye Hospital of Wenzhou Medical University (Hangzhou Branch) from June 2016 to June 2020 were reviewed, and they were analyzed by 3 age groups. There were 87, 41, and 41 patients in three age groups, 1 to 6 months, 7 to 12 months, and 13 to 36 months, respectively; 108 patients with bilateral affected eyes and 61 patients with unilateral affected eyes were included; 84 patients with partial opacity lens and 85 patients with total opacity lens were included. The right eyes of the patients with bilateral congenital cataract were selected for analysis. Statistical analysis of ocular biological parameters between groups was performed using the independent samples t-test and paired samples t-test. Statistical analysis of the relationship between age in months and biological parameters was performed using the Pearson's correlation test. Results: The axial length at the age of 1 to 6 months in the affected eyes of patients with bilateral cataract was (17.59±1.19) mm, it was shorter than the affected eyes of patients with unilateral cataract [(18.18±1.34) mm], and the axial length in the affected eyes of patients with unilateral cataract were shorter than the healthy eyes [(19.01±0.93) mm]. At the age of 7 to 12 months, the axial length in the affected eyes of patients with unilateral cataract [(19.89±0.74) mm] was shorter than the healthy eyes [(20.48±0.43) mm]. The differences were statistically significant (t=-2.06, -5.62, -3.47, all P<0.05). The axial length in the affected eyes with partial opacity at the age of 1 to 6 months was shorter than those with total opacity [(17.43±1.14) mm vs. (18.06±1.29) mm; t=-2.38, P=0.020]. The difference in axial length (affected eyes vs. healthy eyes) was significantly correlated with the age in months in partial cataract (r=0.53, P=0.001). The corneal curvature in the affected eyes of patients with unilateral cataract was flatter than the healthy eyes at the age of 7 to 12 months [(42.41±1.82) D vs. (43.19±1.96) D; t=-2.29, P=0.038], but was steeper at the age of 13 to 36 months [(43.36±2.32) D vs. (42.55±1.88) D; t=2.17, P=0.043]. The anterior chamber depth in the affected eyes of patients with unilateral cataract was less than the healthy eyes at the age of 1 to 6 months [(2.44±0.37) mm vs. (2.58±0.33) mm; t=-2.08, P=0.048].The central corneal thickness in the affected eyes of patients with unilateral cataract was thicker than the healthy eyes both at the age of 1 to 6 months and 7 to 12 months [(555.26±46.95) μm vs. (541.85±40.78) μm, (542.93±27.63) μm vs. (530.93±30.36) μm; t=3.82, 2.26; P=0.001, 0.040]. Conclusions: Congenital cataracts maybe affect the early development of axial length, corneal curvature, anterior chamber depth and central corneal thickness. The degree of lens opacity maybe affecte the early axial length development. The axial length in eyes with partial opacity can be shorter than those with total opacity before the age of 6 months, and thereafter gradually outnumbered the latter.