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D. Kim, J. Seo, S. Kim, K. Park; Comparison of Localized Retinal Nerve Fiber Layer Defects Between a Low–Teen Group and a High–Teen Group in Normal–Tension Glaucoma Patients . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3377.
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© ARVO (1962-2015); The Authors (2016-present)
To compare the pattern of localized retinal nerve fiber layer (RNFL) defects between a low–teen group and a high–teen group in normal–tension glaucoma (NTG) patients.
Seventy–nine eyes of 79 consecutive NTG patients showing localized RNFL defects on RNFL photographs and corresponding early to moderate visual filed defects at the initial visit to a glaucoma specialist were selected for this study. All participants completed refraction, diurnal intraocular pressure (IOP) measurement, central corneal thickness (CCT) measurement, stereoscopic disc photography, RNFL photography, and automated perimetry. On RNFL photograph, Angle α and Angle ß were measured to represent RNFL defect. Angle α is the minimum angle which is made by a line from the center of the optic disc to the center of the macula and a line from the center of the optic disc to the optic disc margin where the nearest border of the RNFL defect meet the optic disc. Angle ß is the summated width of the circumferential angle of the RNFL defects. The patients were divided into two groups according to the level of IOP. A low–teen group had the highest IOP of < 15 mmHg (Group A) and a high–teen group had the lowest IOP of ≥ 15 mmHg (Group B). Patient’s age, highest IOP, CCT, Angle α, Angle ß, mean deviation (MD) and pattern standard deviation (PSD) of Humphrey C30–2 threshold visual field, and systemic diseases were compared between two groups.
Age at the diagnosis of NTG (54.1 ± 12.6 yrs vs. 50.9 ± 13.2 yrs, P=.28), MD (–3.49 ± 3.03 dB vs. –3.38 ± 2.94 dB, P=.86), PSD (5.87 ± 4.02 dB vs. 6.17 ± 4.05 dB, P=.75), and systemic diseases (30% vs. 29%, P=1.00) were not different between Group A and Group B. The highest IOP was 13.8 ± 1.2 mmHg in Group A and 19.0 ± 1.5 mmHg in Group B (P=.00). CCT was not different between two groups (522.4 ± 30.5 µm vs. 511.5 ± 28.4 µm, P=.13). Angle α was significantly smaller in Group A than in Group B (36.8 ± 14.0° vs. 57.2 ± 22.6°, P=.00), while Angle ß was not different between two groups (39.8 ± 17.6° vs. 35.9 ± 14.8°, P=.29).
Localized RNFL defect was closer to the center of the macula in Group A than in Group B, while width of defects was not different between two groups. This finding suggests that different pathogenic mechanism may exist in the RNFL defect in NTG.
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