Abstract
Purpose: :
Neuro fiber layer thickness (NFLT) is an important factor in evaluating the progression of glaucoma. However, normalized NFLT data for the Japanese population are not available. In this study, we surveyed the NFLT from non-glaucomatous (NG) and glaucomatous patients in order to clarify the characteristics of NFLT among the Japanese population.Material and
Methods: :
We retrospectively reviewed the clinical records of patients who received OCT 3000 Fast NFL measurements in the Yamada Eye Clinic from Jan 2006 to Dec 2008. The patients had primary open angle glaucoma (POAG), normal tension glaucoma (NTG), primary angle closure (PAC), and no glaucoma. Patients with ocular diseases which may affect NFLT (including high myopia and retinal degeneration) were excluded. We only included data which measured > 5 signal intensity and represented an accurate scanning shape. Statistical analysis included all the data (circular 256 points/eye) in each of the groups obtained using repeated measures ANOVA and Fisher’s PLSD were used as post hoc tests. To simplify the analysis, 8 points (temporal (T), temporal upper (TU), upper (U), nasal upper (NU), nasal (N), nasal lower (NL), lower (L), temporal lower (TL)) were selected.
Results: :
The data for a total of 1202 NG eyes (745 patients), 85 NTG eyes (43 patients), 69 POAG eyes (53 patients), and 52 PAC eyes (34 patients) were retrieved. The demographics of the groups were as follows: (average age, age range), NG (55, 3-93), NTG (63, 34-84), POAG (63, 32-82), and PAC (67, 56-78). The NFLT of NTG and POAG eyes was statistically smaller than that of NG eyes (p<0.01) in all selected points except T. The NFLT of PAC eyes was smaller than that of NG in T, TU, and TL (p<0.03), but larger in U, NU, N, and L (pP<0.03). The NFLT of PAC eyes was larger than that of NTG and POAG eyes in most points (p<0.01) except T, TU, and TL.
Conclusions: :
The NFLT of NTG and POAG eyes was generally smaller than that of NG and PAC eyes. This suggests that OCT is helpful in detecting NFL thinning in major glaucoma patients in a less invasive manner. The pattern of NFLT differed even in NG and PAC eyes and showed that PAC characteristics is differ not only in axial length, but also in NFLT.
Keywords: nerve fiber layer • imaging/image analysis: clinical