[Analysis of retinal nerve fiber layer thickness in superior segmental optic hypoplasia (SSOH)].

PURPOSE

To evaluate the clinical characteristics of patients with superior segmental optic hypoplasia (SSOH) and quantitatively assess the structural characteristics using optical coherence tomography (OCT).

METHODS

Forty-three eyes of 43 subjects with SSOH and 30 eyes of 30 normal subjects as controls (mean age; 40.2 +/- 14.1, 42.9 +/- 9.9 years, mean refraction; - 4.6 +/- 3.7 D, -3.6 +/- 2.7 D, mean intraocular pressure; 14.6 +/- 2.5 mmHg, 14.3 +/- 3.2 mmHg, Humphrey visual field mean deviation; -4.31 +/- 4.3 dB, 0.01 +/- 1.2 dB) were enrolled. Forty-three eyes of the 43 patients with SSOH were examined by OCT for the quantitative assessment of the RNFL thickness (RNFLT). For the comparison of RNFLT, total average thickness, four quadrants and clock hour-based (12 equal 30 degree sectors) RNFLT were analyzed using OCT.

RESULTS

OCT showed that the eyes with SSOH had significantly thinner RNFL than the normal subjects in total average thickness (SSOH 81.2 mm vs. 105.0 mm, p < 0.0001). Except for the temporal guadrant (p = 0.31), RNFL was thinner in superior, nasal(both p < 0.0001) and inferior (p = 0.002) guadrant. A comparison between the SSOH group and the normal control group for the 12 clock-hour segments in the OCT demonstrated that the patients with SSOH had decreased peripapillary RNFL thickness; the difference was statistically significant, except for the 7, 8, 9 and 10 o'clock segments. The area under the receiver operator characteristic curve (AUC) was greatest for the RNFL thickness of the 12 o'clock segment (AUC = 0.93), followed by the 1 o'clock segment (AUC = 0.90), and the 2 o'clock segment (AUC- = 0.87), as measured by the OCT.

CONCLUSIONS

More generalized thinning of the RNFL and decreasing total average thickness except for the RNFL from 7 o'clock to 10 o'clock were identified in the eyes with SSOH with a relatively superior entrance of the central retinal artery and thinning of the superior retinal nerve fiber layer. It was also demonstrated that segments 12, 1 and 2 o'clock of the SSOH were highly useful for differential diagnosis.