Purpose: To determine the clinical features of patients diagnosed with superior segmental optic hypoplasia (SSOH) and to quantitatively compare retinal nerve fiber layer (RNFL) thickness in SSOH eyes, to that in normal subjects.
Study design: Retrospective comparative case series.
Methods: We examined the medical charts of 106 eyes of 59 patients with SSOH and 35 eyes of 35 normal subjects as controls. Forty-four of 59 patients had been examined by spectral-domain optical coherence tomography (SD-OCT). Eyes with SSOH were classified into a definite and a suspect type determined by standard automated perimetry. The definite type had inferior visual field (VF) defects, while the suspect type did not have inferior VF defects. The findings of the SD-OCT images of 35 eyes with SSOH were compared to those of the 35 normal eyes.
Results: Of the 106 eyes with SSOH, 56 (52.8%) were classified as the definite type and 50 (47.2%) as the suspect type. OCT showed that the average of the total RNFL thickness was significantly thinner in the SSOH group than in the normal group (P < 0.001; Mann-Whitney U test). Sectorial analysis demonstrated that the RNFL was thinner than controls in all quadrants (all P < 0.001; Mann-Whitney U test). The comparison of the hourly sectors showed that the RNFL was thinner at 10, 11, 12, 1, 2, 3, 5, and 6 o'clock sectors in the SSOH group than controls.
Conclusions: Approximately one-half of eyes with SSOH had a detectable VF defect. OCT showed that eyes with SSOH have a thinner RNFL than controls except in 4 o`clock and from 7 o'clock to 9 o'clock.
Keywords: Optical coherence tomography; Retinal nerve fiber layer; Superior segmental optic hypoplasia; Visual field defect.