# Superior Segmental Optic Nerve Hypoplasia: A Case Report and Literature Review

## TL;DR

This paper reports a rare case of optic nerve underdevelopment in a child linked to gestational diabetes, highlighting new insights into retinal changes using modern imaging.

## Contribution

The paper presents an atypical case of SSONH associated with gestational diabetes and explores previously unexamined retinal changes using OCT.

## Key findings

- SSONH was found in a child with maternal gestational diabetes, not type 1 diabetes.
- Modern OCT revealed changes in retinal nerve fibre layer and ganglion cell layer.
- Prompt diagnosis of SSONH can prevent unnecessary investigations and long-term follow-up.

## Abstract

Superior segmental optic nerve hypoplasia (SSONH) is a rare congenital anomaly in which there is underdevelopment of the superior part of the optic nerve. This leads to a reduction in the total nerve fibres constituting the optic nerve and can result in inferior visual field loss. SSONH is classically associated with maternal type 1 diabetes mellitus. We report an atypical case of SSONH associated with maternal gestational diabetes but with no prior history of maternal type 1 diabetes. We comment on the associated retinal nerve fibre layer (RNFL) changes, and also the corresponding ganglion cell layer (GCL) changes, which have not previously been explored using modern optical coherence tomography (OCT) macular segmentation. We discuss previous case reports on SSONH and outline the associated conditions. This review highlights the importance of correct and prompt diagnosis of this rare condition to avoid unnecessary investigation and undue long-term follow-up.