Nerve Fiber Layer Cross-section Research Articles

Pseudoexfoliation: Normative Data and Associations. The Central India Eye and Medical Study

PurposeTo assess the prevalence of pseudoexfoliation (PEX) and its associations in a population-based setting.DesignPopulation-based, cross-sectional study.MethodsThe Central India Eye and Medical Study included 4711 individuals. All study participants underwent a detailed ophthalmological examination. After medical pupil dilation, PEX was assessed by an experienced ophthalmologist using slit-lamp based biomicroscopy.ResultsSlit lamp examination results were available for 4646 (98.6%) study participants with a mean age of 49.3±13.3 years (range: 30–100 years). PEX was detected in 87 eyes (prevalence: 0.95±0.10% (95%CI: 0.75, 1.15) of 69 subjects (prevalence: 1.49±0.18% (95%CI: 1.14, 1.83). PEX prevalence increased significantly (P<0.001) from 0% in the age group of 30–39 years, to 2.85±0.56% in the age group of 60–69 years, to 6.60±1.21% in the age group of 70–79 years, and to 12.3±4.11% in the age group of 80+ years. In multivariate analysis, PEX prevalence was associated with higher age (P<0.001; regression coefficient B:0.11; odds ratio (OR): 1.11 (95%CI: 1.09, 1.13)), lower body mass index (P = 0.001; B: −0.12; OR: 0.88 (95CI: 0.82, 0.95)) and higher diastolic blood pressure (P = 0.002; B: 0.02; OR: 1.03 (95%CI: 1.01, 1.04)). In the multivariate analysis, PEX was not associated with retinal nerve fiber layer cross section area (P = 0.76) and presence of open-angle glaucoma (P = 0.15).ConclusionsIn a rural Central Indian population aged 30+ years, PEX prevalence (mean: 1.49±0.18%) was significantly associated with older age, lower body mass index and higher diastolic blood pressure. It was not significantly associated with optic nerve head measurements, refractive error, any ocular biometric parameter, nuclear cataract, early age-related macular degeneration and retinal vein occlusion, diabetes mellitus, smoking, and dyslipidemia.

Measurement and analysis of optic disc parameters in Mongolian and Han healthy subjects with or without family history of glaucoma

Objective To measure optic disc parameters in Mongolian and Han healthy subjects with or without family history of glaucoma,to explore the causes of the differences and their significance in the diagnosis of early glaucoma.Methods Fifteen healthy Mongolian individuals (30 eyes),30 healthy Han individuals (60 eyes) with a family history of open-angle (30 eyes) or angle-closure (30 eyes) glaucoma,and 45 healthy Han individuals (90 eyes) without a family history of glaucoma were enrolled in this study.The 45 healthy Han individuals without a family history of glaucoma included three age-groups:20 to 29 years old group,30 to 39 years old group and 40 to 49 years old group,each group have 15 subjects (30 eyes).Thirteen parameters were measured by Heidelberg retina tomography (HRT) for all subjects,including disc area,cup area,rim area,cup volume,rim volume,cup/disc area ratio,linear cup/disc ratio,mean cup depth,maximum cup depth,cup shape,disc height variation contour,mean retinal nerve fiber layer (RNFL) thickness and optic nerve fiber layer cross-sectional area.The results were analyzed and compared between the above groups.Results There was no statistically significant (t=0.791,P=0.132) of the height variation contour between Mongolian and Han without a family history of glaucoma (20 to 29 years old) group.The other parameters of Mongolian were smaller than Han without a family history of glaucoma (20 to 29 years old) group,but the difference was not statistically significant (t=-1.039,-0.799,-0.840,-1.108,-0.956,-0.695,-0.931,-1.099,-1.074,-0.580,-0.204,-1.425; P＞ 0.05).The parameters in Han with a family history of open-angle glaucoma group were bigger than Han without a family history of glaucoma (30 to 39 years old) group.The differences were statistically significant for disc area,cup area,rim area,cup volume,rim volume,cup area ratio,linear cup/disc ratio,mean cup depth,cup shape measure,nerve fiber layer cross-sectional area (t =4.758,3.187,2.544,2.674,1.798,3.676,2.721,2.715,2.510,2.373; P＜0.05),but were not statistically significant for maximum cup depth,disc height variation contour and mean RNFL thickness (t=1.649,1.565,0.767; P＞0.05).Most parameters in Han with a family history of angle-closure glaucoma group were the same as that in Han without a family history of glaucoma (40 to 49 years old) group,including cup area,rim area,cup volume,rim volume,cup/disc area ratio,linear cup/disc ratio,mean optic cup depth,maximum cup depth,cup shape,disc height variation contour,mean RNFL thickness,optic nerve fiber layer cross-section (t=1.201,1.697,1.000,0.516,0.740,-0.172,-0.070,-0.972,1.530,-0.390,-0.091,0.659; P＞ 0.05) ; but the difference of disc area between these 2 groups was statistically significant (t=2.224,P＜0.05).Conclusions The family history of glaucoma can change the optic disc parameters of healthy individuals,especially those with a family history of open-angle glaucoma.There is no difference of optic disc parameters between healthy Mongolian and Han subjects. Key words: Optic disk/anatomy & histology; Optic disk/physiopathology; Glaucoma/diagnosis

Pseudoexfoliation: normative data and associations. The Central India Eye and Medical Study

AbstractPurpose To assess the prevalence of pseudoexfoliation (PEX) and its associations in a population‐based setting.Methods The population‐based Central India Eye and Medical Study included 4711 individuals. All study participants underwent a detailed ophthalmological examination. After medical pupil dilation, PEX was assessed by an experienced ophthalmologist using slit‐lamp based biomicroscopy.Results PEX was detected in 87 eyes (prevalence: 0.950.10% (95%CI:0.75,1.15) of 69 subjects (prevalence: 1.490.18% (95%CI:1.14,1.83). In multivariate analysis, PEX prevalence was associated with higher age (P&lt;0.001; OR:1.11), lower body mass index (P=0.001) and higher diastolic blood pressure (P=0.002). In the multivariate analysis, PEX was not associated with retinal nerve fiber layer cross section area (P=0.76) and presence of open‐angle glaucoma (P=0.15). Side differences in the presence of PEX were not significantly associated with side differences in intraocular pressure (P=0.40).Conclusion In a rural Central Indian population aged 30+ years, PEX prevalence (mean: 1.490.18%) was significantly associated with older age, lower body mass index and higher diastolic blood pressure. It was not significantly associated with optic nerve head measurements, refractive error, any ocular biometric parameter, nuclear cataract, early age‐related macular degeneration and retinal vein occlusion, diabetes mellitus, smoking, and dyslipidemia.

Tomographic characteristics of optic nerve head on Heidelberg retina tomograph III in healthy Chinese subjects

Background Normal adult optic disc rim width follows inferior ≥ superior ≥ nasal ≥ temporal (ISNT) rule.Analysis of the optic disc structural parameters with Heidelberg retina tomograph (HRT) can understand whether ISNT principle is suitable to other optic disc structure parameters.Objective This study was to investigate the characteristics of optic nerve head structure parameters in normal Chinese adults.Methods The parents of twins who participated Guangzhou Twin Eye Study were enrolled in Zhongshan Ophthalmic Center from 2006 June to 2011 August.All subjects received the routine eye examinations,including visual acuity,slit lamp microscope,direct ophthalmoscope examination,auto-refraction examination and HRT Ⅲ examination.All data from the right eyes were collected and analyzed.HRT values from different quadrants of optical nerve head were compared with one-way analysis of variance,and the multiple comparison between quadrants was carried out by Bonferroni test.The differences of optical nerve head parameters in different gender were analyzed using independent sample t test and Bland-Altman test.Results In this study,1672 eyes of 1672 subjects were included,with the 759 male and 913 female persons and average age of (41.8±5.3)years.No significant differences were seen in the disc area (DA)between the superior and inferior,as well as the nasal and temporal quadrants among the subjects (P＞0.05).In addition,there were not significantly different in the rim area (RA) between the superior and nasal disc as well as the rim volume (RV) among the inferior,superior and nasal disc (P＞O.05).However,significant differences were found in the cup area (CA),cup/disk area ratio (C/DAR),cup volume (CV),mean cupdepth (MCD),maximum cup depth (MxCD),height variation contour (HVC),cup shape measure (CSM),mean retinal nerve fiber layer thickness (mRNFLT) and retinal nerve fiber layer cross section area (RNFLcsa) among the different quadrants (P＜0.001).The local differences from only DA and RA complied with an ordination of the ISNT rule.The values of DA,CA,C/DAR,CV,MCD,MxCD from male individuals were higher,but those of the RV,HVC,mRNFLT RNFLcsa were lower in comparison with female individuals.Nevertheless,all the differences were ＜ 0.1 with a maximal mean difference in DA and CA (both 0.07 mm2).Conclusions The optical nerve head configurations measured by HRT have different distributing characteristics in four quadrants in normal adults.Most parameters show the higher values in the inferior and superior than those in nasal and temporal of disc,but DA and RA meet ISNT rule.The differences of most parameters between male and female subjects can be ignored. Key words: Bio-metrics; Optic nerve head/parameter, structure; Tomography/method; Heidelberg retinal tomograph; Adult; Gender

Morphometric characteristics of optic disk with disk hemorrhage in normal-tension glaucoma

PURPOSE: To evaluate the morphometric characteristics of the optic disk in eyes with and without disk hemorrhage in normal-tension glaucoma. METHODS: This was a prospective study conducted at Gifu University Hospital of 50 eyes of 50 patients with normal-tension glaucoma (12 men, 38 women; age, 56.5 ± 14.1 years) who had developed new disk hemorrhage at the time of enrollment and 58 eyes of 58 patients with normal-tension glaucoma (20 men, 38 women; age, 56.7 ± 12.4 years) with no history of disk hemorrhage during the follow-up period of more than 2 years. Age and global indexes of the visual field were matched. We morphometrically compared the optic disk with and without hemorrhage using a scanning laser tomograph. Global and sector analyses were made of the optic disk structural parameters. RESULTS: There was no significant difference in the global values of the disk parameters between the disk hemorrhage and the nonhemorrhage groups. However, the inferotemporal values for the rim area, rim volume, mean retinal nerve fiber layer thickness, and retinal nerve fiber layer cross-section area in the disk hemorrhage group were significantly smaller than those in the nonhemorrhage group ( P < .05). In the disk hemorrhage group, moreover, the values for the rim area, rim volume, and retinal nerve fiber layer cross-section area in the inferotemporal sector with hemorrhage were significantly smaller than those in the same sector without hemorrhage ( P < .05). CONCLUSION: Localized damage of the disk rim and retinal nerve fiber layer at the inferotemporal sector was prominent in eyes with disk hemorrhage.

Interocular differences in optic disc topographic parameters in normal subjects

Purpose. To test the interocular differences in optic disc topography in normal subjects by means of confocal scanning laser ophthalmoscopy. Methods. Topographic measurements of the optic disc were evaluated by means of confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph) in 314 eyes of 157 healthy volunteers. The examination was started randomly either with the right eye or the left eye. Differences between right and left eyes in disc area, cup area, cup volume, cup/disc area ratio, rim area, rim volume, maximum cup depth, cup shape measure, retinal nerve fiber layer thickness, and retinal nerve fiber cross section area for 360° and for the temporal and nasal regions of the optic nerve head were evaluated by means of Student t-test. The same parameters were assessed in a subgroup of 80 elderly (age > 50 years) healthy subjects. Holm's sequentially rejective method was used for significance correction of multiple comparisons. Results. Significant interocular differences in the average retinal nerve fiber layer thickness (p = 0.0010) and retinal nerve fiber layer cross section area (p = 0.0036) were found, with the right eye showing, on the average, lower values.The left eye showed a larger retinal nerve fiber layer thickness in 94 subjects (59.87%) and a larger retinal nerve fiber cross section area in 101 subjects (64.33%). In the temporal optic disc area there were no statistically significant differences in topometric data (p > 0.05). In the nasal area, significant interocular differences in the retinal nerve fiber layer thickness (p = 0.0002) and retinal nerve fiber layer cross section area (p = 0.0003) were found. Similar results were found when the group of subjects older than 50 years was considered. Conclusions. This study demonstrates systematic interocular differences in optic disc topometric data. Such a finding, be it due to methodological or biological reasons, should be taken in consideration in clinical trials.

Correlation Between the Visual Field Indices and Heidelberg Retina Tomograph Parameters

We wished to determine whether a relationship exists between Heidelberg retina tomograph (HRT) parameters and the visual field indices. One eye was randomly chosen from 59 normal patients [normal visual field and normal optic nerve head (ONH) and intraocular pressure (IOP) < 21 mm Hg], 64 ocular hypertensive patients (normal visual field and normal OHN and IOP > 22 mm Hg), 124 high-tension glaucoma patients (abnormal visual field and/or abnormal optic nerve and IOP > 22 mm Hg) and 47 low-tension glaucoma patients (abnormal visual field and or optic disc and IOP < 21 mm Hg). All the patients were examined with Humphrey Perimeter, program 30-2, and HRT. Findings were assessed by analysis of variance, Pearson's correlation coefficient, and multiple linear regression. Among all subjects, we noted a statistically significant correlation (Pearson's r, p < 0.001) between cup area, cup/disc area ratio, rim area, rim volume, cup shape measure, and retinal nerve fiber layer cross-section area with mean deviation and corrected pattern SD. Multiple linear regression analysis demonstrated that rim area was the most important predictor of mean deviation and corrected pattern SD. The presence of significant correlations between some HRT parameters, such as rim area and cup shape measure and visual field indices, suggests that these HRT parameters could be good indicators of the degree of glaucomatous ONH damage.

Ranked-Segment Distribution Curve for Interpretation of Optic Nerve Topography

The objective of this article was to evaluate whether a new method for analysis of optic nerve topography, the ranked-segment distribution (RSD) curve, can differentiate between normal and glaucoma eyes. Topographic optic nerve parameters of 39 normal subjects aged 50-79 years were measured using a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph). Disc parameters were determined from the mean topography of three images of each eye obtained with a 15 degrees field of view. Rim area and retinal nerve fiber layer cross-section area were measured in 36 segments (each of 10 degrees) around the disc margin. For each parameter, the 36 segments were ranked in descending order and graphically depicted as the RSD curve. In normal eyes, the fifth percentile values for each of the ranked segments were calculated and graphed to compare with glaucoma eyes within the same age group. Evaluation of RSD curves was done automatically with a computer program using predefined criteria. Three primary open-angle glaucoma cases are presented to demonstrate the RSD curve method. In these three glaucoma eyes, RSD curves demonstrated defects more consistently than stereoscopic disc photography, nerve fiber layer photography, and computerized visual field testing. In two cases, RSD curves differentiated between diffuse and localized defect as well as demonstrated the locations of the defects. The RSD curve technique may assist in the interpretation of topographic optic nerve parameters and in the detection of glaucomatous optic neuropathy.

Association Between Quantitative Nerve Fiber Layer Measurement and Visual Field Loss in Glaucoma

To evaluate the association between quantitative nerve fiber layer measurements and visual field loss in patients with primary open-angle glaucoma. Quantitative retinal nerve fiber layer measurements were obtained in 53 patients with primary open-angle glaucoma by using confocal scanning laser ophthalmoscopy (cross-section area) and confocal scanning laser polarimetry (retardation ratio). For each eye, three images were obtained with each instrument. An image that was the mean of those three was created and used in all analyses. We investigated the association between global, regional, and hemifield differences in retinal nerve fiber layer measurements and visual field loss with linear regression techniques. The retardation ratio decreased with increasing mean visual field loss, measured both globally and regionally; R2 (the amount of variation explained by the model) ranged from 8% to 21%. Retinal nerve fiber layer cross-section area was not significantly associated with global measures of visual field loss. The inferior visual field mean deviation increased with decreasing superior retinal nerve fiber layer cross-section area (R2 = 8.2%, P = .04); superior visual field mean deviation was not associated with inferior retinal nerve fiber layer cross-section area (R2 = 2.6%, P = .25). Hemifield differences in visual field mean deviation increased with increasing hemifield differences in retinal nerve fiber layer cross-section area (R2 = 20.0%, P < .001), but not with retardation ratio (R2 = 0.9%, P = .48). Quantitative measures of the retinal nerve fiber layer using both confocal scanning laser ophthalmoscopy and confocal scanning laser polarimetry were correlated with visual field loss in glaucoma patients.