Differentiation by imaging of superior segmental optic hypoplasia and normal-tension glaucoma with inferior visual field defects only

Purpose

To differentiate superior segmental optic hypoplasia (SSOH) from normal-tension glaucoma (NTG) with inferior visual field defects only.

Methods

Eighteen eyes with SSOH (SSOH group) and 19 eyes with NTG (NTG group) were examined by optical coherence tomography (OCT), Heidelberg retina tomography (Heidelberg Retinal Tomograph II, HRT II) and standard automated perimetry.

Results

Retinal nerve fiber layer thickness (RNFLT) based on OCT measurements was significantly reduced (thinner) in the superior to superonasal sectors and significantly greater (thicker) in the inferotemporal sector in the SSOH group than in the NTG group. The cup was significantly smaller and the rim significantly larger in the superotemporal and temporal sectors in the SSOH group than in the NTG group based on HRT II measurements. The greatest area under the receiver operating characteristic curve for discrimination of SSOH from NTG by OCT and HRT II was for the RNFLT ratio of 1 + 2 o’clock/10 + 11 o’clock (0.985) and for the ratio of the superonasal to superotemporal sector of rim to disc area ratio and cup to disc area ratio (0.955), respectively. The frequent location of the inferior visual field defects corresponded to the difference in structural changes in both groups.

Conclusions

Comparison of the superonasal to superotemporal sectors by OCT and HRT II were useful in differentiating SSOH from NTG with only inferior visual field defects.