Purpose:
Superior segmental optic hypoplasia (SSOH) is known to have an inferior sector-like visual field defect and normal visual acuity. SSOH is an important differential diagnosis of normal tension glaucoma (NTG). Furthermore SSOH may be associated with NTG, which makes glaucoma management more complicated. The purpose of this study is to evaluate and compare retinal nerve fiber layer (RNFL) thickness between SSOH and NTG with inferior visual field defect using Cirrus optical coherence tomography (OCT).
Methods:
Twenty-eight eyes from 25 patients (5 men and 20 women, 65.7±16 years old) with SSOH, 18 eyes of 15 patients (6 men and 9 women, 73.8±14.8 years old) with NTG with inferior visual field defect and 10 eyes of 10 normal control subjects (1 men and 9 women, 51.5±8.4 years old) were included. In addition to detailed ophthalmoscopic examination and visual field testing with Humphrey Field Analyzer and Goldmann perimetry, Cirrus OCT was performed for quantitative assessment of the peripapillary RNFL thickness in all subjects.
Results:
The RNFL thickness of the patients with SSOH and NTG showed generalized decrease compared to that of normal subjects (p<0.01).A comparison of RNFL thickness among SSOH group, NTG group and normal control group for twelve 30°-subdivided segments demonstrated that the patients with SSOH had significantly decreased RNFL thickness between 90° and 150°. A comparison between NTG group and SSOH group demonstrated that the patients with NTG had significantly decreased RNFL thickness between 30° and 60° (P<0.01, Student-Newman-Keuls test).
Conclusions:
SSOH showed significant thinning of RNFL at 90° -150° , whereas NTG with inferior visual field defect showed significant thinning at 30° -60°. The difference of RNFL thickness distribution among SSOH, NTG and normal subjects could be useful for differential diagnosis of SSOH and NTG with inferior visual field defect.
Keywords: imaging/image analysis: clinical • optic nerve • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)