The retinal nerve fiber layer in normal eyes

The retinal nerve fiber layer is different in normal and glaucomatous eyes. The authors used red-free photographs to examine the retinal nerve fiber layer in 234 normal eyes. The retinal nerve fiber layer was most visible in the inferior temporal arcade, followed by the superior temporal arcade, then by the temporal macular area, and finally the nasal area. This distribution was significantly (P less than 0.0001) correlated to (1) the configuration of the neuroretinal rim, which was significantly broadest at the inferior disc pole followed by the superior one, (2) the juxtapapillary caliber of the retinal vessels, which were significantly wider in the inferior temporal arcade than in the superior temporal arcade, and (3) the location of the foveola 0.53 +/- 0.34 mm inferior to the middle point of the vertical optic disc axis. The retinal nerve fiber layer decreased with age. No correlation occurred with sex or right or left eye. No localized retinal nerve fiber layer defects were seen. These features of the normal retinal nerve fiber layer are important for diagnosis of retinal nerve fiber layer changes secondary to optic nerve damage in the diseased eye.     

The retinal nerve fiber layer in normal and glaucomatous eyes. II. Correlations

The retinal nerve fiber layer is different in normal and glaucomatous eyes. We correlated semi-quantitative data of the retinal nerve fiber layer of 398 eyes with chronic primary open-angle glaucoma and of 234 normal eyes with the intra- and parapapillary morphometric signs and with the perimetric indices. The three parameters "sequence of the fundus sectors concerning the best visibility of the retinal nerve fiber bundles", "visibility of the nerve fiber bundles", and "localized defects" were significantly (p less than 0.001) correlated to 1) area of the neuroretinal rim as a whole and in four different optic disc sectors, 2) neuroretinal rim width determined every 30 degrees, 3) optic cup area, diameters and form, 4) horizontal and vertical cup/disc ratios and the quotient of the horizontal to vertical cup/disc ratio, 5) area and width of zone "Alpha", zone "Beta", and the total parapapillary chorio-retinal atrophy, 6) diameter of the retinal vessels, 7) grade of a "tesselated fundus", and 8) the visual field loss. If only the inferior temporal and the superior temporal sectors were considered, the retinal nerve fiber bundles were less visible in that sector with the largest notch in the neuroretinal rim, the smaller neuroretinal rim area and width, the thinner retinal vessels, and the larger zone "Alpha", zone "Beta", and total parapapillary chorio-retinal atrophy. The glaucomatous changes in the retinal nerve fiber layer are correlated in time and location with the intra- and parapapillary and the perimetric alterations. Evaluation of the retinal nerve fiber layer is a useful method to detect a glaucomatous optic nerve damage.(ABSTRACT TRUNCATED AT 250 WORDS)     

应用视神经纤维分析仪检测正常人视网膜神经纤维层厚度

目的 探讨正常人的视网膜神经纤维层厚度及其象限比值与年龄的关系。方法 应用视神经每人义检测１９８例（１９８只眼）正常志愿者,并按年龄分组进行统计分析。结果 ＲＮＦＬＴ与年龄成负相关,上、下方象限厚度较鼻、颞侧大,与年龄相关、鼻、颞侧无此特点。上、下方象限厚度比值平均为１．０４１。结论 ＮＦＡ是测量ＲＮＦＬＴ的可靠方法,正常人的ＲＮＦＬＴ随年龄的增长而减少。     

屈光不正性弱视患者视网膜厚度的变化

目的:探讨视网膜厚度分析仪(retinalthicknessanalyzer,RTA)对弱视患者的诊断价值。方法:采用RTA测量正常人6例11眼及弱视患者22例31眼,眼后极部视网膜厚度值及厚度地形图,所得数据经SPSS统计软件包进行分析。结果:正常人平均视网膜厚度为172.4±13.4μm,鼻侧较颞侧厚(P<0.05),其中黄斑上方为177.1±9.0μm,黄斑下方为169.9±11.0μm;鼻侧为180.5±1.3μm,颞侧为161.0±9.2μm。弱视患者平均视网膜厚度为176.4±7.4μm。在黄斑中心凹X5区,弱视明显厚于正常人。黄斑上方为178.7±20.2μm,黄斑下方为173.4±26.2μm;鼻侧为177.3±9.6μm,颞侧为173.4±6.2μm。结论:正常眼鼻侧视网膜明显较颞侧厚。弱视眼在黄斑中心凹X5区视网膜厚度明显较正常眼厚。     

Nerve fiber analyzer measuring retinal nerve fiber layer thickness in normal and glaucomatous eyes

目的客观测量和比较青光眼病人与正常人视网膜神经纤维层（ＲＮＦＬ）厚度。方法用神经纤维分析仪（ＮＦＡ）对１５例（２５眼）开角青光眼病人及２５例（４２眼）正常人视盘区神经纤维层厚度进行测量,然后经计算机自动分析求出上、下、颞、鼻４个区ＲＮＦＬ厚度及平均厚度,所得数据经统计学分析。结果青光眼患者上、下区域ＲＮＦＬ平均厚度分别为（８４．４７±１２．０９）μｍ和（７７．４９±１６．６３）μｍ,总平均厚度（７２．５１±１２．０９）μｍ,均低于正常人［分别为（１０４．９２±２０．５６）μｍ,（９５．４８±１５．６２）μｍ和（８６．１５±１４．７５）μｍ）］,统计学差异有显著意义（Ｐ＜０．０１）;颞、鼻侧厚度与正常人差异不明显。结论ＲＮＦＬ厚度分析可望作为青光眼早期诊断依据之一。     

Parapapillary retinal vessel diameter in normal and glaucoma eyes. I. Morphometric data

The retinal blood vessels serve for nutrition of the retinal ganglion cells and their axons. This study was undertaken to evaluate the vessel diameter in normal and glaucoma eyes. The calibers of the superior temporal and inferior temporal retinal artery and vein were measured at the optic disc border and at a distance of 2 mm from the optic disc center; 473 eyes of 281 patients suffering from chronic primary open-angle glaucoma and 275 eyes of 173 normal subjects were examined. Fifteen-degree, color stereo optic disc photographs were used. In the normal eyes the inferior temporal vessels were significantly larger than the superior temporal vessels. This corresponds with: (1) the configuration of the normal neuroretinal rim, which is significantly broader in the inferior disc region than in the superior disc area; (2) the visibility of the retinal nerve fibers, which are better detectable in the inferior temporal area than in the superior temporal one; and (3) the foveola location 0.53 +/- 0.34 mm inferior to the optic disc center. The retinal vessel diameter was independent of the patients' age and optic disc and parapapillary chorioretinal atrophy size. In the glaucoma group the vessel caliber was significantly smaller than in the normal eyes. The differences were more marked for the arteries and the inferior temporal vessels, respectively. The vessel diameters decreased significantly with increasing glaucoma stage independently of the patients' age. The parapapillary retinal vessel diameter may reflect the need of vascular supply in the corresponding superficial retinal area. It may be correlated with the local ganglion cell density and retinal nerve fiber layer thickness.     

Optic nerve and retinal nerve fiber layer analyzers in glaucoma

There is mounting evidence that retinal nerve fiber layer (RNFL) loss precedes detectable visual field loss in early glaucomatous optic neuropathy. However, examination and photography of the RNFL is a difficult technique in many patients, particularly older individuals, and eyes with small pupils and media opacities. It is subjective, qualitative, variably reproducible, and often unreliable. Furthermore, optic nerve head and RNFL photography is time consuming, operator dependent, has limited sensitivity and specificity, and requires storage space. Imaging technologies have emerged which enable clinicians to perform accurate, objective, and quantitative measurements of the RNFL and optic nerve head topography. There is good agreement between such measurements and clinical estimates of optic nerve head structure and visual function. The reproducibility of these instruments suggests that they have the potential to detect structural change over time. This report will review the technological principles, reproducibility, sensitivity and specificity, capacity to detect glaucomatous progression, and limitations of currently available ocular imaging technologies.     

Peripapillary retinal nerve fiber layer thickness in normal Japanese eyes measured with optical coherence tomography

Purpose  

To measure peripapillary retinal nerve fiber layer (RNFL) thickness in healthy Japanese individuals using optical coherence tomography (OCT).     

Evaluation of the retinal nerve fiber layer in glaucoma

The health of the optic nerve in glaucoma can be evaluated by examination of the retinal nerve fiber layer with red free illumination. Retinal nerve fiber layer defects have been shown in some studies to precede enlargement of optic cupping and visual field defects in glaucoma patients. Detection of glaucomatous damage at an earlier stage in the disease may prevent subsequent visual field loss. Retinal nerve fiber layer evaluation may give important information in the management and treatment of glaucoma patients.     

Preservation of nerve fiber layer by retinal vessels in glaucoma.

The authors evaluated the correlation between various parameters and the local preservation of the retinal nerve fiber layer in 156 glaucomatous eyes. A vessel-associated preservation of the nerve fiber layer was observed in 45 of the 156 glaucomatous eyes. The presence of "straight" retinal vessels (either arterioles or large venules) and "tortuous" retinal vessels (large or small venules) inside of the scleral ring was correlated with the local preservation of the nerve fiber layer (P less than 0.001 and P less than 0.05, respectively). A local elevation of the floor of the cup was also correlated with the preservation of the nerve fiber layer (P less than 0.01). However, no correlation existed between either the preservation of the nerve fiber layer and the type of glaucoma, sex or age of patient, tilting of the disc, cilioretinal vessel, vertical cup-to-disc ratio, refractive error, disc size, distance between the disc and foveola, or the index of ovalness of the disc. These results suggest that retinal vessels in the disc significantly influence the vulnerability of the nerve fibers to glaucomatous damage.     

The investigation of retinal nerve fiber layer thickness in eyes with optic nerve head drusen

Purpose: To investigate the effect of optic nerve head drusen (ONHD) on the retinal nerve fiber layer (RNFL) thickness. Patients and methods: Twenty-one nonglaucomatous eyes with various degrees of ONHD and 27 age-matched control eyes were included in the study. Visual fields and RNFL thickness were assessed using Humphrey field analyzer and optical coherence tomography (OCT), respectively. The eyes with various degrees of ONHD and the control eyes were compared with regard to visual field (VF) indices and RNFL thicknesses. Results: VF indices of the eyes with ONHD were significantly different from those of the control eyes (p < 0.05), but no significant difference existed among the eyes with various degrees of ONHD (p > 0.05). The RNFL thicknesses of inferior quadrants of the eyes with ONHD were significantly thinner than those of the control eyes (p < 0.05). A significant thinning of the RNFL in the superior and nasal quadrants was observed in grade II and III discs, while temporal quadrants only in grade III discs presented a similar change (p < 0.05). A comparison between the RNFL thicknesses of various degrees of ONHD did not show a significant statistical difference (p > 0.05) except for the thickness in the temporal RNFL (p < 0.05). Conclusion: We found a significant decrease in the RNFL thickness of ONHD patients compared to that of the control subjects. The measurements of VF indices did not show a significant difference between various degrees of ONHD. In contrast, RNFL thickness was significantly correlated with the amount of ONHD. This suggests that OCT may allow the detection of early changes in RNFL thickness in ONHD patients before observable changes in the visual field are seen.     

Optic disc rim area to retinal nerve fiber layer thickness correlation: comparison of diabetic and normal tension glaucoma eyes

Purpose

To compare the correlation between optic disc rim area and retinal nerve fiber layer thickness (rim-RNFL correlation) in diabetic eyes with non-progressive RNFL defects and normal tension glaucoma (NTG) eyes.

Methods

Seventy-three eyes of 73 patients with preperimetric or early NTG and 25 eyes of 25 type II diabetes patients with a non-progressive RNFL defect for ≥5 years were enrolled in this retrospective cohort study. Rim areas and RNFL thicknesses were measured by Heidelberg retina tomography (HRT II) and by optical coherence tomography (Cirrus OCT), in global and 12 clock-hour parameters. Diabetic eyes were evaluated whether they were above the 95 % prediction interval (PI) for the rim-RNFL correlation of NTG.

Results

A significant linear rim-RNFL correlation was observed in NTG eyes globally and at all clock-hours, except in the 4 and 9 o’clock areas, (0.08 < r ² < 0.56, P < 0.05). Eighty-four percent of the diabetic eyes were above the 95 % PI of the rim-RNFL correlation of NTG in ≥2 clock-hours, as compared with 36 % of the eyes in the global parameter.

Conclusions

The eyes of diabetic patients with non-progressive RNFL were well-differentiated from NTG eyes by the rim-RNFL correlation.     

Pattern of retinal nerve fiber layer damage in Korean eyes with normal-tension glaucoma and hemifield visual field defect

PURPOSE: To evaluate quantitatively the pattern of retinal nerve fiber layer (RNFL) damage in eyes with normal-tension glaucoma (NTG) with hemifield dominant visual field defects using scanning laser polarimetry. METHODS: Prospectively, 40 consecutive eyes from 40 patients with NTG and hemifield defect based on the findings of examination using the Humphrey Field Analyzer underwent RNFL thickness measurements. Twenty normal eyes from 20 subjects matched in age and refractive error formed a control group. RESULTS: Symmetry, calculated as the ratio of superior to inferior RNFL thickness, showed no statistically significant difference between the study group and the control group ( P=0.50). Overall, 27.5% (11/40 eyes) showed an "abnormal" symmetry index that indicated focal RNFL change. The affected ratio, calculated as the ratio of RNFL thickness in the quadrant corresponding to the hemifield of visual field defect to that of the temporal quadrant was significantly lower in the study group than in the control group ( P<0.0001). A similar finding was noted for the unaffected ratio. CONCLUSION: Despite strict selection of the eyes with visual field defect confined to one hemifield, a mixture of both focal and diffuse RNFL damage was noted, with a common occurrence of symmetrical RNFL thinning in both upper and lower quadrants based on scanning laser polarimetry.     

Retinal nerve fiber layer measurement by nerve fiber analyzer in normal subjects and patients with glaucoma.

OBJECTIVE: To identify the pattern of retinal nerve fiber layer (RNFL) loss in glaucoma using the Nerve Fiber Analyzer (NFA). DESIGN: Case-control study. PARTICIPANTS: A total of 80 normal and 75 age- and race-matched chronic open-angle glaucoma subjects were recruited. INTERVENTION: The RNFL thickness was assessed with a scanning laser polarimeter (Nerve Fiber Analyzer GDX, Laser Diagnostic Technologies Inc., San Diego, CA). Analysis of variance was used to compare the corresponding RNFL measurement indices of the different groups. MAIN OUTCOME MEASURES: Superior/nasal (S/N) and inferior/nasal (I/N) ratios of NFA are sensitive parameters to differentiate between glaucoma and nonglaucoma subjects. RESULTS: Peripapillary RNFL measurements at the superior and inferior regions were significantly lower in the glaucoma group (P<0.001) but were similar in temporal and nasal regions (P>0.05). Using nasal value as reference, S/N and I/N ratios were significantly lower in the glaucoma groups (P<0.001) and also decreased with increasing severity of glaucoma. CONCLUSIONS: In glaucoma, RNFL was more susceptible to loss in the superior and inferior regions than in the nasal and temporal regions. The S/N and I/N ratio parameters provided by the NFA appeared to give further discriminating ability in early glaucoma.     

Color vision and retinal nerve fiber layer in early glaucoma

We tested 47 eyes in 47 patients (ten normal subjects, 15 with suspected glaucoma, and 22 with glaucoma) with the Pickford-Nicholson anomaloscope to assess the retinal nerve fiber layer and measure color vision. The 47 subjects were randomly selected from a group of 132 for whom Farnsworth-Munsell 100-hue color error scores were known. The yellow-blue and green-blue anomaloscopic matching ranges correlated significantly with diffuse retinal nerve fiber loss. There was no correlation with localized retinal nerve fiber loss.     

Thicknesses of the fovea and retinal nerve fiber layer in amblyopic and normal eyes in children

PURPOSE: This study was designed to assess and compare the thicknesses of the fovea and the retinal nerve fiber layer in normal children and children with amblyopia. METHODS: Optical Coherence Tomography (OCT) was performed on 26 children (52 eyes total) with unilateral amblyopia that was due to anisometropia or strabismus. OCT was also performed on 42 normal children (84 eyes), for a total of 136 eyes. Retinal thickness measurements were taken from the fovea, and the retinal nerve fiber layer thickness measurements were taken from the superior, inferior, nasal and temporal quadrants in the peripapillary region. RESULTS: The average age of the normal children was 8.5 years, and the average age of the children with amblyopia was 8.0 years. The average thickness of the fovea was 157.4 microm in normal eyes and was 158.8 microm in amblyopic eyes. The difference between the two groups was not statistically significant (p = 0.551). The thicknesses of the superior, inferior, nasal and temporal quadrants of the retinal nerve fiber layer between the normal children and the children with amblyopia were also not statistically significant (p = 0.751, 0.228, 0.696 and 0.228, respectively). However, for the children with anisometropic amblyopia and the children with strabismic amblyopia, the average thicknesses of the fovea were 146.5 microm and 173.1 microm, respectively, and the retinal nerve fiber layer thicknesses were measured to be 112.9 microm and 92.8 microm, respectively, and these were statistically significant differences (p = 0.046, 0.034, respectively). CONCLUSIONS: Normal thicknesses of the fovea and the retinal nerve fiber layers were established, and there were no differences in the fovea and the retinal nerve fiber layer thickness found between normal children and children with amblyopia.     

视网膜神经纤维层检测在诊断青光眼及近视合并青光眼中的价值

视网膜神经纤维层(retinal nerve fiber layer,RNFL)厚度的现代检测手段主要有海德堡视网膜断层扫描仪、光学相干断层成像术和偏振激光扫描仪等。检测RNFL厚度可以对青光眼的早期诊断提供依据。与青光眼一样,近视眼的RNFL也会变薄。所以近视合并青光眼时经常容易被误诊而延误青光眼的治疗时机。因此我们必须将单纯近视眼与近视合并青光眼区别开来。对RNFL的检测能否将单纯近视眼及近视合并青光眼区别开,国内外学者存在不同观点,现综述如下。