Nanophthalmos in children: morphometric and clinical characterization

To report clinical and morphometric characteristics of children with nanophthalmos and to identify possible risk factors associated with occludable angles.

The medical records of children (<18 years of age) with nanophthalmos examined from January 2016 to December 2016 were reviewed retrospectively. Demographic and examination details, including cycloplegic refraction, best-corrected visual acuity, intraocular pressure (IOP), gonioscopy, and fundus examination, were extracted for analysis. Biometric data included axial length, anterior chamber depth, and lens thickness. Subgroup data from children with occludable and open angles on gonioscopy were compared.

A total of 75 children were included. Mean age at presentation was 10.92 ± 4.97 years. Mean spherical equivalent was +13.31 ± 2.69 D. Best-corrected visual acuity was 20/40 or better in 26 eyes (35%). Ametropic amblyopia was leading cause of visual impairment in our series. IOP was within normal limits (10-21 mm Hg) in 73 subjects and above normal in 2. Of the 75 children, 17 had occludable angles. Posterior segment anomalies were found in 28. Mean axial length was 16.88 ± 1.5 mm, mean anterior chamber depth was 3.00 ± 0.5 mm, and mean lens thickness was 3.9 ± 0.5 mm. The ratio of lens thickness to axial length was 0.253 ± 0.025 in subjects with occludable angles; 0.226 ± 0.038, in those with open angle. A ratio of >0.239 increased the risk of having angle closure by nearly three times.

In this study cohort, nanophthalmos was characterized by short axial length and high hyperopia, with shallow anterior chamber. Nearly 20% of children had occludable angles requiring intervention. Clinicians should monitor the ratio of lens thickness to axial length to ensure that angle closure is prevented.