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Changes in Retinal Nerve Fiber Layer Reflectance Intensity as a Predictor of Functional Progression in Glaucoma
摘要： PURPOSE. We determined whether longitudinal changes in retinal nerve fiber layer (RNFL) reflectance provide useful prognostic information about longitudinal changes in function in glaucoma. METHODS. The reflectance intensity of each pixel within spectral-domain optical coherence tomography (SD-OCT) circle scans was extracted by custom software. A repeatability cohort comprising 53 eyes of 27 participants (average visual field mean deviation [MD] (cid:2)1.65 dB) was tested five times within a few weeks. To minimize test–retest variability in their data, a reflectance intensity ratio was defined as the mean reflectance intensity of pixels within the RNFL divided by the mean between the RNFL and RPE. This was measured in a separate longitudinal cohort comprising 310 eyes of 205 participants tested eight times at 6-month intervals (average MD, (cid:2)0.99 dB; median rate of change, (cid:2)0.09 dB/y). The rate of change of this ratio, together with the rate of RNFL thinning, and their interaction, were used to predict the rate of change of MD. RESULTS. In univariate analyses, the rate of RNFL thinning was predictive of the rate of MD change (P < 0.0001), but the rate of change of reflectance intensity ratio was not (P ? 0.116). However, in a multivariable model, the interaction between these two rates significantly improved upon predictions of the rate of functional change made using RNFL thickness alone (P ? 0.038). CONCLUSIONS. For a given rate of RNFL thinning, a reduction in the RNFL reflectance intensity ratio is associated with more rapid functional deterioration. Incorporating SD-OCT reflectance information may improve the structure–function relation in glaucoma.
关键词： RNFL,reflectance,OCT
更新于2025-09-23 15:21:01
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Diffuse Retinal Nerve Fiber Layer Defects Identification and Quantification in Thickness Maps
摘要： PURPOSE. To report retinal nerve fiber layer (RNFL) defect identification and quantification in RNFL thickness maps according to the structural RNFL loss, and to evaluate diffuse RNFL defects. METHODS. A total of 170 patients with glaucoma and 186 normal subjects were consecutively enrolled. We defined RNFL defects in an RNFL thickness map by the degree of RNFL loss. The reference level for RNFL defect determination was set as a 20% to 70% degree of RNFL loss with a 1% interval. To identify RNFL defects, each individual RNFL thickness map was compared to the normative database map by using MATLAB software, and the region below the reference level was detected. The area, volume, location, and angular width of each RNFL defect were measured. Diffuse RNFL defects were defined as having an angular width > 30°. RESULTS. The optimal reference level for glaucomatous RNFL defects identification was 42% loss of RNFL. Retinal nerve fiber layer defects were identified in all (100%) of the 170 glaucoma patients and false-positive RNFL defects were detected in 16 (8.16%) cases among the 186 normal subjects. In all, 64.1% of glaucoma patients had diffuse RNFL defects, and 47.7% of diffuse RNFL defects were associated with mild glaucoma patients. The volume of diffuse RNFL defects was significantly associated with the severity of glaucomatous damage (P = 0.009). Diffuse RNFL defects were located closer to the center of the optic disc than localized RNFL defects (P < 0.001). CONCLUSIONS. Retinal nerve fiber layer thickness map analysis is an effective method for analyzing RNFL defects. Quantitative measurements (area, volume, location, and width) were useful to understanding diffuse RNFL defects.
关键词： OCT,diffuse RNFL defect,RNFL thickness map,retinal nerve fiber layer
更新于2025-09-19 17:15:36
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The Relationship Between Retinal Nerve Fiber Layer Thickness and Optic Nerve Head Neuroretinal Rim Tissue in Glaucoma
摘要： PURPOSE. The purpose of this study was to determine the relationship between optical coherence tomography (OCT) measures of retinal nerve fiber layer (RNFL) and neuroretinal rim (NRR) in a nonhuman primate experimental glaucoma model, and in a population of clinical patients. METHODS. For nonhuman primates, normative data were collected from 44 healthy monkeys, and nine animals with unilateral experimental glaucoma that were followed longitudinally. Cross-sectional human subjects data were collected from 89 healthy, 74 glaucoma suspects, and 104 glaucoma patients. Individualized transverse scaling for OCT scans was calculated using a schematic eye that incorporated optical ocular biometry. Custom algorithms were used to quantify RNFL thickness with and without vessels removed, scaled minimum rim width (sMRW), and neural rim volume (NRV). RESULTS. For the experimental glaucoma group, NRR parameters showed the first changes with increased cumulative IOP. The data for both NRR and RNFL measures were best fit by an exponential rise model (NRV, R2 ? 0.79, P < 0.01, sMRW, R2 ? 0.74, P < 0.01). The major retinal vascular thickness contribution to the RNFL decreased (0.03 lm/lm, P < 0.01) with RNFL loss, but the percent vascular contribution increased ((cid:2)0.1%/lm, P < 0.01) with disease progression. Overall, the findings for the cross-sectional human data were similar to those of the experimental model. CONCLUSIONS. The findings illustrate a nonlinear relationship between NRR and RNFL measures and provide support for the use of multiple OCT scaled morphological measures for the diagnosis and management of primary open angle glaucoma in humans.
关键词： glaucoma,neuroretinal rim,RNFL,optical coherence tomography
更新于2025-09-19 17:15:36
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Response of the Retinal Nerve Fiber Layer Reflectance and Thickness to Optic Nerve Crush
摘要： PURPOSE. To study the effects of acute optic nerve damage on the re?ectance of the retinal nerve ?ber layer (RNFL) and to compare the time courses of changes of RNFL re?ectance and thickness. METHODS. A rat model of optic nerve crush (ONC) was compared with previously studied normal retinas. The re?ectance and thickness of the RNFL were studied at 1 to 5 weeks after ONC. Re?ectance spectra from 400 to 830 nm were measured for eyes with ONC, their contralateral untreated eyes, and eyes with sham surgery. Directional re?ectance was studied by varying the angle of incidence. RNFL thickness was measured by confocal microscopy. RESULTS. After ONC, the RNFL re?ectance remained directional. At 1 week, RNFL re?ectance decreased signi?cantly at all wavelengths (P < 0.001), whereas there was no signi?cant change in RNFL thickness (P ? 0.739). At 2 weeks, both RNFL re?ectance and thickness decreased signi?cantly, and by 5 weeks they declined to approximately 40% and 30%, respectively, of the normal values. Although RNFL re?ectance decreased at all wavelengths, there was a greater reduction at short wavelengths. Spectral shape at long wavelengths was similar to the normal. Some of these changes were also found in the contralateral untreated eyes, but none of these changes were found in eyes with sham surgery. CONCLUSIONS. Decrease of RNFL re?ectance after ONC occurs prior to thinning of the RNFL and the decrease is more prominent at short wavelengths. Direct measurement of RNFL re?ectance, especially at short wavelengths, may provide early detection of axonal damage.
关键词： optic nerve crush,optical properties,thinning of the RNFL,directional reflectance,retinal nerve fiber layer
更新于2025-09-19 17:15:36
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Optic nerve head width and retinal nerve fiber layer changes are good indexes for validating the successful induction of experimental anterior ischemic optic neuropathy
摘要： Reproducible skills are essential for successful induction of a rat model of anterior ischemic optic neuropathy (rAION). We established an in vivo validation index by measuring the natural course of optic nerve head (ONH) width and retinal nerve fiber layer (RNFL) thickness in the rAION model using optical coherence tomography (OCT). The rAION model was induced by photodynamic operations. We measured the ONH width and RNFL thickness in the acute stage (<3 days), subacute stage (day 7 and day 14) and later stage (day 28) post-infarct by OCT. RNFL were measured by hematoxylin and eosin stain (HE) to confirm the OCT findings. The RGCs survival rate was determined by retrograde Fluoro-gold labeling, and the visual function was assessed with flash visual-evoked potentials (FVEPs) 4 weeks post-infarct. The ONH showed significant swelling in the acute stage, which also correlated with RNFL swelling. The swelling was reduced to normal within one-week post-infarct. The rAION group (0.51± 0.12 mm2) showed a significant RNFL thinning when compared with sham groups (0.92±0.15 mm2, p<0.05) on day-28 post-infarct. And HE-stained retina cross sections also showed RNFL thinning, which further confirmed our OCT Findings. The RGC density and P1-N2 amplitude were significantly reduced in rAION. Swelling, reduction of swelling, and atrophy of RNFL in acute, sub-acute, and later stage, respectively, are important events for confirming the successful induction of rAION. They suggest that the longitudinal OCT data provides a reliable index for validating the reproducibility and correct order of rAION.
关键词： optic nerve head (ONH),retinal ganglion cells (RGCs),optical coherence tomography (OCT),anterior ischemic optic neuropathy in rats (rAION),retina nerve fiber layer (RNFL)
更新于2025-09-04 15:30:14
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Comparison study of OCT, HRT and VF findings among normal controls and patients with pseudoexfoliation, with or without increased IOP
摘要： Purpose: To compare and evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) measurements obtained with the optical coherence tomography (OCT) and the Heidelberg retina tomography (HRT) to visual field (VF) parameters in normal and in patients with pseudoexfoliation with or without increased intraocular pressure (IOP). Methods: A total of 96 subjects were included in our study aged between 65 years and 78 years. The normal group consisted of 28 subjects (14 men and 14 women). Out of the total number of patients, 68 patients who showed pseudoexfoliation (21 men and 47 women) were divided into two groups. Of these, the first group had pseudoexfoliation with increased IOP and the second group showed deposits of pseudoexfoliative material without an increase in IOP. The normal controls were randomly chosen and restricted to those without any glaucomatous optic disc damages, VF defects, and an IOP 15 mmHg. All subjects were prospectively included for repeated measurements of IOP, OCT, HRT, and VFs during the same visit by the same examiner and all measurements were repeated every 3 months. Results: Mean RNFL thickness measured by OCT was larger in the normal controls than in the other two groups (98.04 μm (first group) vs 75.42 μm and 97.02 μm (second group), P0.05). Four-quadrant RNFL thickness measurements were significantly different between the normal and the group 1 (P0.05) but not with the group 2 (P0.05). Rim area had a mean difference of -0.44, whereas cup-to-disc ratio (C/D) showed a mean difference of 0.31, thus being significantly different between the normal and the two groups (all P0.05). The median of the mean deviation parameter of VFs was -0.28 for the normal vs -0.32 and -0.18 for the other two groups, whereas pattern standard deviation median difference was 0.89 for the normal and 1.32 and 1.20 for the other two groups, respectively (P0.05). Conclusion: Both OCT and HRT showed early ONH and RNFL changes in their parameters and did not correlate with the normal findings of the automated perimetry.
关键词： retinal nerve fiber layer (RNFL),visual fields (VFs),pseudoexfoliation glaucoma,pseudoexfoliation syndrome,Heidelberg retina tomograph (HRT),optical coherence tomography (OCT)
更新于2025-09-04 15:30:14