Comparison of the Detection Rate, Location and Amount of Retinal Nerve Fiber Layer Defect

PURPOSE: To compare the detection rate of the patients with retinal nerve fiber layer (RNFL) defect and the amount of RNFL defect according to the patients' age. METHODS: Retrospective chart reviews of 22,811 subjects, who visited the health care center from January 2009 to December 2009 were performed. The detection rate, location and average amount of RNFL defect and the proportions of the patients who were diagnosed with glaucoma through Humphrey visual field (HVF) test or determined as a glaucomatous optic disc were compared according to the patients' age. RESULTS: The proportions of the patients whose RNFL defect were detected was highest in the patients 60 years old or older (2.3%) and was statistically significant (p = 0.012). However, there was no significant difference among the other age groups (under 40 years: 1.7%, 40 thru 49 years: 1.5%, 50 thru 59 years: 2.0%). The proportions of the patients who were determined as glaucoma through the HVF test or glaucomatous optic disc were also highest in the patients 60 years old or older (1.4%), however, there was no statistically significant difference (p = 0.070) among the age groups (under 40 years: 1.1%, 40 thru 49 years: 0.9%, 50 thru 59 years: 1.2%). CONCLUSIONS: The RNFL defect is likely to be detected in subjects less than 40 years of age and the detection rate is similar to subjects in their 40's and 50's. The use of fundus photography to detect RNFL defect in a health care center is recommended in subjects under 40 years of age.

Analysis of Localized Retinal Nerve Fiber Layer Defects not Detected by Optical Coherence Tomography

PURPOSE: To analyze localized RNFL defect cases that were identified in retinal nerve fiber layer (RNFL) fundus photographs but not in optical coherence tomography (OCT). METHODS: Analysis of OCT scans and images was performed for 14 eyes (17 locations) that showed localized RNFL defects in RNFL fundus photographs but not in RNFL thickness average analysis. RESULTS: With respect to the range of RNFL defects, 41.2% were less than 10degrees, 47.0% were 11 to 20degrees, and 11.8% were 21 to 30degrees. In 71.4% of the RNFL cases the defects were less than 10degrees and the decrease of RNFL thickness was not readily observable on the OCT scan images. In all cases of RNFL defects in the 11 to 30degrees range the decrease in RNFL thickness could be assessed on the OCT scan images. Nonetheless, the decrease of RNFL thickness could not be seen on the OCT analysis images in which the results of the RNFL thickness made through an automated computer algorithm were displayed. CONCLUSIONS: The range of localized RNFL defects that were difficult to detect with OCT consisted of those cases that were almost less than 20degrees. The limitations of the OCT scan itself in patients with RNFL with an angular width defect less than 10degrees and the problems of RNFL thickness analysis processing in patients with an angular width of 11 to 30degrees may decrease the sensitivity of OCT in diagnosing RNFL defects.

Retinal Nerve Fiber Layer Thickness Analysis in Early Glaucoma

PURPOSE: To investigate the difference between superior and inferior peripapillary retinal nerve fiber layer (RNFL) thickness in early glaucoma patients who have RNFL defect in either superior quadrant or inferior quadrant and to determine if it can be useful to detect early glaucomatous change. METHODS: Eighty eight patients with early glaucoma who have RNFL defect in either the superior quadrant or the inferior quadrant as confirmed by red free photograph (40 eyes with normal standard automated perimetry and 48 eyes with early glaucomatous visual field loss) were divided into the superior RNFL defect group and the inferior RNFL defect group. The average RNFL thickness was measured in the superior and inferior quadrants using optical coherence tomography and the thickness differences between the superior and the inferior quadrants (S-I difference) were compared among early glaucoma eyes and 59 normal controls. Then, discriminative power of the S-I difference was assessed by area under ROC (AUROC). RESULTS: The average thickness of the RNFL showed a statistically significant difference between early glaucoma eyes and normal controls (P<0.05). S-I differences of the superior RNFL defect group and inferior RNFL defect group in preperimetric patients and in early perimetric patients were -20.5+/-16.4 micrometer and 15.0+/-14.2 micrometer, -24.0+/-17.2 micrometer and 18.4+/-16.7 micrometer, respectively, which were significantly greater than that of the normal control group (-8.2+/-17.1 micrometer). AUROC of S-I difference in the superior and inferior defect groups of preperimetric patients were 0.691, 0.872, respectively. CONCLUSIONS: The difference in RNFL thickness between the superior and inferior quadrants (S-I difference) in early glaucoma patients was larger than in normal controls. We expect that this parameter of RNFL analysis using OCT can be useful in detecting early glaucoma.

Assessment of Retinal Ganglion Cell using Retinal Nerve Fiber Layer Photography in Age-related Macular Degeneration

PURPOSE: To determine the loss of ganglion cell layer (GCL) neurons in patients with age-related macular degeneration (AMD) with choroidal neovascularization (CNV). METHODS: Retinal nerve fiber layer (RNFL) photography was taken in patients with AMD with CNV to assess the presence of RNFL defects in the papillomacular bundle area. Patients with other ocular disorders or a history of previous intraocular surgery or laser treatment were excluded from this study. RESULTS: Eighty-five eyes in 65 patients were included, of which only one (1.2%) showed papillomacular bundle defects in association with CNV. CONCLUSIONS: From this study, the majority of the patients with AMD with CNV had no papillomacular bundle defect, which demonstrates that considerable amount of GCL is maintained in AMD.