Diffuse Retinal Nerve Fiber Layer Research Articles

A Case of Nonarteritic Anterior Ischemic Optic Neuropathy after Intravitreal Aflibercept Injection

Purpose: To report a case of nonarteritic anterior ischemic optic neuropathy (NAION) development after intravitreal injection of aflibercept.Case summary: A 71-year-old female presented with decreased visual acuity and was diagnosed with wet macular degeneration in the right eye. She received two intravitreal aflibercept injections. After 1 month, the best-corrected visual acuity (BCVA) had improved. However, the inferior rim of the optic disc was blurred and an inferior retinal nerve fiber layer (RNFL) swelling was observed. The patient received one more intravitreal aflibercept injection (a loading dose). After 2 weeks, the patient presented with sudden vision loss and the BCVA was finger-counting at 50 cm. Fundus examination revealed that the total optic disc rim was blurred and optical coherence tomography demonstrated diffuse RNFL swelling. The patient was diagnosed with NAION. After 2 months, the optic disc appeared pale but without blurring of the rim, and diffuse thinning of the RNFL was observed. Her BCVA had not improved up to 6 months of follow-up.Conclusions: Although NAION after intravitreal injection is uncommon, physicians should not only examine the macula but also comprehensively assess the intraocular pressure, the RNFL profile, and the optic disc head, especially in patients with NAION risk factors.

Understanding the role of microperimetry in glaucoma.

The present narrative review attempts to provide an overview on the use of microperimetry or fundus-driven perimetry in glaucoma, considering the clinical use, the different strategies and limits compared to standard automated perimetry. An electronic database (PubMed and Medline) search was performed of articles of any type published in the English language between 1998 and 2020 with a combination of the following terms: microperimetry, glaucoma, primary open-angle chronic glaucoma, visual field, Humphrey visual field, fundus automated perimetry. All the original articles, case reports, and short series analyzed were included in the present review, offering an excursus on the strengths and limitations characterizing the use of microperimetry in glaucomatous patients. The characteristics of a recently introduced fundus-driven perimetry Compass (CMP; Centervue, Padua, Italy) were also included. Although there remain several contradictions regarding routine use of microperimetry and the restricted research on this topic limits our ability to draw firm conclusions, microperimetry may be preferable in cases of localized retinal nerve fiber layer defects in patients with primary open-angle glaucoma and normal visual field. However, standard automated perimetry remains the gold standard for monitoring glaucoma, especially in patients with diffuse retinal nerve fiber layer impairment and visual field defects. The newly introduced Compass device can potentially provide a more accurate structural-functional evaluation than standard automated perimetry and can therefore produce superior testing reliability.

Characteristics of diffuse retinal nerve fiber layer defects in red-free photographs as observed in optical coherence tomography en face images

BackgroudTo determine whether diffuse retinal nerve fiber layer (RNFL) defects, identified on red-free fundus photographs, could be identified on optical coherence tomography (OCT) en face structural images and to evaluate which factors are related to the different recognition patterns on en face images.MethodsThis retrospective, cross-sectional study included open-angle glaucoma eyes with diffuse RNFL defects in the inferior hemifield, identified in red-free photographs. The corresponding OCT en face structural images were divided into 3 groups: (1) no defect, (2) localized defect, and (3) diffuse defect. We compared the demographic and clinical ocular characteristics among the groups.ResultsA total of 209 eyes from 157 patients were included. The distribution of OCT en face images was: no defect, 25 eyes (11.96%); localized defect, 106 eyes (50.72%); diffuse defect, 78 eyes (37.32%). Logistic regression analysis revealed that eyes with greater mean deviation (P = 0.004) and thicker inferior RNFL (P = 0.008) would be included in the no defect and localized defect groups based on OCT en face images, rather than in the diffuse defect group.ConclusionAround half of diffuse RNFL defects identified in the red-free photographs appeared as localized defects in OCT en face images. Mild glaucomatous damage was related to no defect and localized defect groups, classified based on the OCT en face images, in eyes with diffuse photographic RNFL defects. OCT en face images may be helpful in further assessing diffuse RNFL defects seen in red-free photographs in eyes with open-angle glaucoma.

Diagnostic Ability of Retinal Nerve Fiber Layer Thickness Deviation Map for Localized and Diffuse Retinal Nerve Fiber Layer Defects.

Purpose. To evaluate the diagnostic ability of the retinal nerve fiber layer (RNFL) deviation map for glaucoma with localized or diffuse RNFL defects. Methods. Eyes of 139 glaucoma patients and 165 healthy subjects were enrolled. All participants were imaged with Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA, USA). A RNFL defect was defined as at least 10 contiguous red (<1% level) superpixels in RNFL deviation map. The area, location, and angular width of RNFL defects were automatically measured. We compared sensitivities, specificities, and area under the receiver operating characteristic curves (AUCs) of RNFL deviation map and circumpapillary RNFL thickness for localized and diffuse RNFL defects. Subgroup analysis was performed according to the severity of glaucoma. Results. For localized defects, the area of RNFL defects (AUC, 0.991; sensitivity, 97%; specificity, 90%) in deviation map showed a higher diagnostic performance (p = 0.002) than the best circumpapillary RNFL parameter (inferior RNFL thickness; AUC, 0.914; sensitivity, 79%; specificity, 92%). For diffuse defects, there was no significant difference between the RNFL deviation map and circumpapillary RNFL parameters. In mild glaucoma with localized defect, RNFL deviation map showed a better diagnostic performance than circumpapillary RNFL measurement. Conclusions. RNFL deviation map is a useful tool for evaluating glaucoma regardless of localized or diffuse defect type and has advantages over circumpapillary RNFL measurement for detecting localized RNFL defects.

Diffuse Retinal Nerve Fiber Layer Defects Identification and Quantification in Thickness Maps

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. 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°. 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). 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.

Quantitative Assessment of Retinal Nerve Fiber Layer Defect Depth Using Spectral-Domain Optical Coherence Tomography

To assess quantitatively the depth of retinal nerve fiber layer (RNFL) defects using a Cirrus high-definition (HD) optical coherence tomography (OCT)-derived RNFL thickness deviation map. Prospective, cross-sectional study. Three-hundred fifteen eyes with localized and diffuse RNFL defects of 315 glaucoma patients and 217 eyes of 217 healthy subjects. For the glaucoma subjects, the severity of the RNFL defect was graded on red-free fundus photographs by 2 observers using a standardized protocol with a 3-level grading system. The RNFL defect depth on the RNFL thickness deviation map was expressed as an RNFL defect depth percentage index (RDPI): 100×(1-[summation of thicknesses of RNFL defects {red or yellow superpixels}/summation of RNFL thicknesses of upper 95th percentile range of age-matched healthy subjects in areas corresponding to RNFL defects]). Retinal nerve fiber layer defect depth percentage index, average and segmental (4 quadrants and 12 clock-hour sectors) circumpapillary RNFL (cpRNFL) thicknesses according to the RNFL defect severity, and the area under the receiver operating characteristic curves (AUROCs) for various OCT parameters. The RDPIs increased with the increasing severity of the RNFL defect in both the superior and inferior hemifields (P <0.05, 1-way analysis of variance test with Bonferroni correction). The AUROCs of the RDPIs (0.969 and 0.975 in the superior and inferior hemifields, respectively) were larger than those of all of the cpRNFL thicknesses in discriminating the mild from the moderate RNFL defects (P <0.05). Meanwhile, in discriminating the moderate from the severe RNFL defects, the AUROCs of the RDPIs (0.961 and 0.891 in the superior and inferior hemifields, respectively) were larger than those of the cpRNFL thicknesses in all areas except the inferior quadrant and the 6-, 7-, and 11-o'clock sectors (P <0.05). The RDPI, a new parameter using a Cirrus HD OCT-derived RNFL thickness deviation map, can be a useful adjunct tool for objective quantification of RNFL defect depth. This parameter has an advantage over cpRNFL thickness in discriminating between mild and moderate RNFL defects, not in discriminating between moderate and severe defects.

Comparison of ability of time-domain and spectral-domain optical coherence tomography to detect diffuse retinal nerve fiber layer atrophy

Our aim was to evaluate and compare diagnostic capabilities of time-domain (Stratus) and spectral-domain (Cirrus) optical coherence tomography (OCT) to detect diffuse retinal nerve fiber layer (RNFL) atrophy. This study assessed 101 eyes from 101 glaucoma patients with diffuse RNFL atrophy and 101 eyes from 101 age-matched healthy individuals. Two experienced glaucoma specialists graded red-free RNFL photographs of eyes with diffuse RNFL atrophy using a four-level grading system. The area under the receiver operating characteristic curves (AUC) of normal eyes was compared with that of eyes with diffuse atrophy. Sensitivity and specificity of each OCT device were calculated on the basis of its internal normative database. The largest AUC for Stratus and Cirrus were obtained for average RNFL thicknesses (0.96 and 0.94, respectively). Comparison of the AUC with different RNFL atrophy grades revealed no significant difference between the two OCT devices. Using an internal normative database at a <5% level, the overall sensitivity of Stratus ranged from 58.0 to 84.0%, whereas that of Cirrus ranged from 75.0 to 87.0%. According to the normative database, the highest Stratus sensitivity was obtained with the temporal-superior-nasal-inferior-temporal (TSNIT) thickness graph, and the highest Cirrus sensitivity with the TSNIT thickness graph and the deviation map. The AUC obtained from Cirrus were comparable with those from Stratus. On the basis of their normative databases, these devices had similar diagnostic accuracy. Our results suggest that the diagnostic capabilities of the two instruments to detect diffuse RNFL atrophy are similar.

Comparison of Sensitivities for Detecting Diffuse and Localized Retinal Nerve Fiber Layer Defects With Time-domain Optical Coherence Tomography in Patients With Glaucoma

To compare the ability of time-domain optical coherence tomography (OCT) to detect diffuse and localized retinal nerve fiber layer (RNFL) defects using a built-in normative database in patients with early to moderate glaucoma. Subjects with localized visual field defects confined to either hemifield were consecutively recruited. Only 1 eye per subject was considered. Among the 91 eyes with localized RNFL defects, 46 eyes with mean deviations matched to those of the 46 eyes with diffuse RNFL defects were selected for statistical analysis. This case-control study included 46 eyes with diffuse RNFL defects and 46 eyes with localized RNFL defects. The fast RNFL thickness protocol of Stratus OCT was used. The clock-hour and quadrant sector parameters corresponding to the hemifield with the visual field defect were evaluated at P<0.05 with regard to the built-in normative database. The sensitivities of these parameters were compared between diffuse and localized RNFL defects. The sensitivity of the clock-hour sector parameter for diffuse RNFL defects (84.8%) was not significantly different than that for localized RNFL defects (80.4%) (P=0.78). The sensitivity of the quadrant sector parameter for diffuse RNFL defects (74.9%) was significantly higher than that for localized RNFL defects (52.3%) (P=0.04). The clock-hour parameter of time-domain OCT detected RNFL defects without significant difference in sensitivities between diffuse and localized patterns of RNFL loss in glaucomatous eyes. However, the quadrant parameter of OCT showed better sensitivity for diffuse RNFL defects than for localized RNFL defects.

Correlation Between Retinal Nerve Fiber Layer Thickness and Visual Field Sensitivity: Diffuse Atrophy Imaging Study

To identify the correlation between retinal nerve fiber layer (RNFL) thickness and visual field sensitivity in healthy eyes with preperimetric and perimetric glaucoma and to estimate the functional RNFL loss in eyes with pre-perimetric glaucoma. One hundred and two eyes with glaucoma and diffuse RNFL atrophy and 102 healthy eyes were enrolled. The correlation between optical coherence tomography (OCT)-measured RNFL thickness of the superior (clock-hour segments 10, 11, 12, 1, 2, and 3) and inferior (clock-hour segments 5, 6, 7, and 8) area and the average total deviations of the inferior and superior hemifields in standard automated perimetry (SAP) were evaluated using the simple linear model, respectively. The OCT-measured RNFL thickness was assumed to comprise functional and residual thicknesses; the residual thickness was calculated from the simple linear model and the eyes with severe diffuse RNFL atrophy. Functional RNFL thickness was compared between groups. Twenty-seven eyes had preperimetric and 75 eyes had perimetric glaucoma. The coefficient of determination (R(2)) of the simple linear model was 0.71 to 0.77 for the correlation between RNFL thickness and total deviation of SAP. The estimated residual thickness was 50.4 to 56.5 μm. On comparison with normal eyes, eyes with preperimetric glaucoma were estimated to have 37% to 41% functional RNFL loss. The correlation between RNFL thickness and SAP sensitivity was well explained by the simple linear model. Approximately 40% loss of the functional RNFL was found in preperimetric glaucoma.

Diagnostic Accuracy of OCT with a Normative Database to Detect Diffuse Retinal Nerve Fiber Layer Atrophy: Diffuse Atrophy Imaging Study

To investigate the diagnostic accuracy of Stratus optical coherence tomography (OCT) with its internal normative database to detect diffuse retinal nerve fiber layer (RNFL) atrophy in glaucoma subjects. One hundred two eyes of 102 glaucoma patients with diffuse RNFL atrophy and 102 healthy eyes of 102 age-matched subjects were enrolled in the Diffuse Atrophy Imaging Study. Two experienced observers graded RNFL photographs of diffuse RNFL atrophy eyes using a four-level grading system. The diagnostic performances for detecting diffuse RNFL atrophy were examined according to visual field results and RNFL photograph grading. Using a criterion of abnormal at the <5% level, the overall sensitivity of the Stratus OCT parameters ranged from 61.5% to 84.5%, and the overall specificity ranged from 90.2% to 99.0%. For mild, moderate, and severe diffuse RNFL atrophy, the superior quadrant had a sensitivity of 41.0%, 83.3%, and 100.0%, respectively, and the inferior quadrant had a sensitivity of 35.0%, 88.5%, and 100.0%, respectively. The highest likelihood ratios were obtained at the 11 and 12 o'clock sectors for superior RNFL and the 6 and 7 o'clock sectors for inferior RNFL. OCT with a normative database can detect diffuse RNFL atrophy with moderate sensitivity and high specificity. Because the sensitivity of Stratus OCT is closely related to the degree of diffuse RNFL atrophy and the visual field results, OCT with an internal normative database should be evaluated with prudence, especially in the early stage of glaucoma with diffuse RNFL atrophy.

Retinal Nerve Fiber Layer Imaging with Spectral-domain Optical Coherence Tomography (OCT)—A Review of the Cirrus HD-OCT

High-speed, high-resolution imaging of the retinal nerve fiber layer (RNFL) with spectral-domain optical coherence tomography (OCT) has become an essential tool for evaluation of glaucoma. The Cirrus HD-OCT (Carl Zeiss Meditec, Inc. Dublin, CA) is a spectral-domain OCT that provides visualization of the distribution pattern and measurement of RNFL abnormalities in a 6x6mm2optic disc region. Analysis of the RNFL thickness deviation map—a color-coded map displaying areas of RNFL abnormalities—detects glaucoma with high sensitivity and specificity. Trend analysis of average and sectorial RNFL thicknesses, and event analysis of the RNFL thickness maps and the RNFL thickness profiles can be used to detect and follow diffuse and focal RNFL progression. RNFL measurement with spectral-domain OCT could provide important information for use in formulating treatment plans and evaluating disease prognosis in the management of glaucoma.

Retinal Nerve Fiber Layer Imaging with Spectral-Domain Optical Coherence Tomography: Pattern of RNFL Defects in Glaucoma

To characterize the distribution pattern, angular width, and area of retinal nerve fiber layer (RNFL) defects in glaucoma using spectral-domain optical coherence tomography (OCT). Prospective, cross-sectional study. We included 113 normal subjects and 116 glaucoma patients. One eye from each individual was randomly selected for Cirrus HD-OCT (Carl Zeiss Meditec Inc., Dublin, CA) RNFL imaging of the 6 × 6-mm² parapapillary region. The RNFL defects were identified in the RNFL thickness deviation map as superpixels coded in red. The angular location and the angular width of RNFL defects were measured. The proportion of area with RNFL measurements within the normal ranges in the RNFL thickness deviation map was expressed as the RNFL area index (RAI): 1 - [area of superpixels coded in red/(6 × 6 - optic disc and parapapillary atrophic area)]. The diagnostic performance between RAI and average RNFL thickness was compared with the area under the receiver operating characteristic curve after adjusting refraction, signal strength, optic disc, and parapapillary atrophic areas. Frequency distribution profiles and distribution patterns of RNFL defects, diagnostic sensitivity and specificity of RAI, and average RNFL thickness. The RNFL defects in glaucoma were most frequently found at the inferotemporal meridian at 284° (80.4%), followed by the superotemporal meridians at 73° (54.2%). The respective proportions of localized (angular width ≤ 30°) and diffuse (angular width > 30°) RNFL defects were 11.4% and 70.5% in mild glaucoma (MD ≥ 6 dB), and 4.2% and 94.5% in moderate to advanced glaucoma (MD < -6 dB). The RAI was 90.2 ± 6.4% and 83.6 ± 7.4% in the mild and moderate to advanced glaucoma groups, respectively. At a specificity of 90.0%, the respective diagnostic sensitivity of RAI and average RNFL thickness was 95.7% (95% confidence interval, 92.2-99.1%) and 94.0% (90.1-99.1%). Analysis of the pattern of RNFL defects with spectral domain OCT imaging offers important insights in understanding the characteristics of RNFL damage. As RNFL defects expand in size as the disease progresses, measurement of the angular width and area of RNFL defects can provide an additional dimension for evaluation of glaucoma.

Quantitative Assessment of Diffuse Retinal Nerve Fiber Layer Atrophy Using Optical Coherence Tomography: Diffuse Atrophy Imaging Study

To evaluate quantitatively the degree of diffuse retinal nerve fiber layer (RNFL) atrophy using Stratus optical coherence tomography (OCT). Prospective, cross-sectional study. One hundred two eyes of 102 patients with diffuse RNFL atrophy and 102 healthy eyes of 102 age-matched subjects were enrolled in the Diffuse Atrophy Imaging Study. Two experienced observers graded RNFL photographs of diffuse RNFL atrophy eyes using a previously reported standardized protocol with a 4-level grading system. Readings were taken from the superior and inferior RNFL areas. The OCT-measured RNFL thickness parameters were compared among normal eyes and diffuse atrophy subgroups. Area under the receiver operating characteristic curves (AROCs) was calculated for various OCT RNFL parameters. Average and segmental (4 quadrants and 12 clock-hours) OCT-measured RNFL thicknesses and AROCs for various OCT parameters. For superior and inferior RNFL areas, diffuse atrophy grading by 2 observers agreed in 82.5% and 83.3% of cases, respectively, with a substantial agreement (kappa value = 0.760 [P < 0.001] and 0.777 [P < 0.001]). Significant differences were observed in RNFL thickness among normal and all diffuse atrophy subgroups, especially in the 7 and 11 o'clock sectors (P < 0.0001). The OCT RNFL thickness measurements decreased with increasing severity of RNFL damage. The 7 and 11 o'clock sectors showed the highest AROCs for discrimination of mild RNFL atrophy from normal eyes (0.972 and 0.979, respectively). The OCT RNFL thickness parameters showed excellent quantitative correlation with the degree of diffuse RNFL atrophy. Our results suggest that Stratus OCT may serve as a useful adjunct in accurately and objectively assessing the degree of diffuse RNFL atrophy.

Diffuse Glaucomatous Structural and Functional Damage in the Hemifield Without Significant Pattern Loss

To compare the retinal nerve fiber layer (RNFL) thickness and retinal sensitivity in the normal visual hemifield of glaucomatous eyes with localized visual field loss with those of normal eyes and eyes with suspected glaucoma, and to evaluate the relationship between RNFL atrophy and glaucoma severity. One randomly selected eye of each subject underwent standard automated perimetry, stereoscopic photography, scanning laser polarimetry with enhanced corneal compensation, and time-domain and spectral-domain optical coherence tomography (OCT). Mean retinal sensitivity values were calculated in the normal standard automated perimetry hemifield of the glaucoma group and randomly selected hemifields in the normal and suspected glaucoma groups. The mean RNFL thickness values corresponding to the normal hemifield were calculated. Glaucoma severity was judged using standard automated perimetry pattern standard deviation and the Heidelberg retina tomograph-derived linear cup-disc ratio. Fifty subjects were enrolled in each group. Mean RNFL thickness in the normal hemifield obtained using spectral-domain OCT, time-domain OCT, and scanning laser polarimetry with enhanced corneal compensation was significantly (P <or= .01) thinner in the glaucoma group compared with the normal and suspected glaucoma groups. Mean retinal sensitivity in the normal hemifield was significantly (P < .001) reduced in the glaucoma group compared with the normal and suspected glaucoma groups. The Heidelberg retina tomograph-derived cup-disc ratio was significantly correlated with mean RNFL thickness in the normal hemifield obtained using spectral-domain OCT, time-domain OCT, and scanning laser polarimetry with enhanced corneal compensation (P <or= .01). Diffuse RNFL atrophy and retinal sensitivity loss exist in glaucomatous eyes with localized standard automated perimetry deficits. Glaucomatous damage affects both structure and function in a linear proportion.

Scanning Laser Polarimetry and Optical Coherence Tomography for Detection of Retinal Nerve Fiber Layer Defects

PurposeTo compare the ability of scanning laser polarimetry with variable corneal compensation (GDx-VCC) and Stratus optical coherence tomography (OCT) to detect photographic retinal nerve fiber layer (RNFL) defects.MethodsThis retrospective cross-sectional study included 45 eyes of 45 consecutive glaucoma patients with RNFL defects in red-free fundus photographs. The superior and inferior temporal quadrants in each eye were included for data analysis separately. The location and presence of RNFL defects seen in red-free fundus photographs were compared with those seen in GDx-VCC deviation maps and OCT RNFL analysis maps for each quadrant.ResultsOf the 90 quadrants (45 eyes), 31 (34%) had no apparent RNFL defects, 29 (32%) had focal RNFL defects, and 30 (33%) had diffuse RNFL defects in red-free fundus photographs. The highest agreement between GDx-VCC and red-free photography was 73% when we defined GDx-VCC RNFL defects as a cluster of three or more color-coded squares (p<5%) along the traveling line of the retinal nerve fiber in the GDx-VCC deviation map (kappa value, 0.388; 95% confidence interval (CI), 0.195 to 0.582). The highest agreement between OCT and red-free photography was 85% (kappa value, 0.666; 95% CI, 0.506 to 0.825) when a value of 5% outside the normal limit for the OCT analysis map was used as a cut-off value for OCT RNFL defects.ConclusionsAccording to the kappa values, the agreement between GDx-VCC deviation maps and red-free photography was poor, whereas the agreement between OCT analysis maps and red-free photography was good.

Retinal Nerve Fiber Layer Measures in High- and Normal-Tension Glaucoma

To use optical coherence tomography (OCT) to investigate the qualitative and quantitative differences in the defects of the retinal nerve fiber layer (RNFL) in subjects with high tension primary open angle glaucoma and subjects with normal tension glaucoma. RNFL was assessed with OCT in 21 eyes with high-tension glaucoma (HTG) and 20 eyes with normal-tension glaucoma (NTG). Regression analyses were performed to investigate the interaction of disease group and location for localized RNFL loss, and to predict diffuse and localized RNFL loss as a function of age, mean defect, spherical equivalent, disease group, and location. Local RNFL thicknesses for superior clock-hour regions were estimated after adjustment for the thicknesses of symmetrically opposed locations. There were no differences in mean age, visual field defect mean deviation, and refractive error between subjects in HTG and NTG groups. Diffuse RNFL thickness was not significantly different between the two groups [mean RNFL for NTG > HTG by 3.48 mum, 95% confidence interval (CI) -3.9 to 10.9 microm, p = 0.092]. There was no significant interaction of group and location for localized RNFL loss (p = 0.916). Local RNFL thickness at superior regions was not significantly different in the two groups, after adjustment for RNFL thickness at corresponding inferior locations (mean RNFL for NTG > HTG by 6.30 microm, 95% CI -1.08 to 13.7 microm, p = 0.34). RNFL thickness decreased, on average (1.88 microm/dB mean deviation, 95% CI 1.21 to 2.55 microm, p < 0.0001) and locally (1.37 microm/dB mean deviation, 95% CI 0.79 to 1.96 microm, p < 0.0001), with increasing severity of glaucoma. There is no difference in the spatial pattern of RNFL defects, as assessed by the OCT, between HTG and NTG.

Retinal nerve fiber layer thickness in nonarteritic anterior ischemic optic neuropathy: OCT characterization of the acute and resolving phases

To evaluate longitudinal changes in retinal nerve fiber layer (RNFL) thickness in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography (OCT). Prospective, observational case series study. Sixteen eyes from 15 consecutive patients affected with NAION were analyzed. The fellow unaffected eyes served as controls. Patients were divided into three different study groups: (1) patients with visual field (VF) defect confined to the inferior hemifield (five eyes), (2) patients with diffuse VF loss (seven eyes), and (3) patients with central or centrocecal scotoma (four eyes). The main outcome was peripapillary RNFL thickness measurement by Stratus-OCT. In group 1, OCT demonstrated RNFL involvement limited to the temporal , superior and nasal optic disc quadrants, both in acute and athophic stages. Diffuse RNFL damage involving all quadrants around the disc was observed in group 2 patients. Group 3, by contrast, revealed RNFL atrophy limited to the superior and temporal sectors of the disc. OCT can identify different patterns of RNFL involvement specific to different classic VF defects in eyes with NAION. Our results corroborate previous histologic findings in optic nerves affected with NAION.

Longitudinal Changes in Retinal Nerve Fiber Layer Thickness after Acute Primary Angle Closure Measured with Optical Coherence Tomography

Longitudinal follow-up of peripapillary retinal nerve fiber layer (RNFL) thickness after an episode of acute primary angle closure (APAC) using Stratus optical coherence tomography (OCT). Seventeen patients who had experienced a single unilateral APAC episode (intraocular pressure, >50 mm Hg) were enrolled. The average and superior, temporal, inferior, and nasal quadrant RNFL thicknesses of the affected and fellow eyes at 1, 4, and 12 weeks after remission were compared by using StratusOCT. The relationship between average RNFL thickness and interval of follow-up were evaluated with regression analysis. The mean duration of the APAC episode was 13.8 hours (range, 3-40). Comparison of the average and four quadrant RNFL thicknesses in the affected eyes longitudinally showed significant differences between 1 and 4, and 1 and 12 weeks, but not between 4 and 12 weeks. The average and four-quadrant RNFL thicknesses for the affected eyes were greater than the analogous values for fellow eyes at 1 week. In contrast, the inferior- and superior-quadrant RNFL thicknesses for the affected eyes were lower at 4 and 12 weeks, whereas the average and nasal quadrant values for the affected eyes were lower than those in fellow eyes at 12 weeks. Average RNFL thickness for the affected eyes was correlated with the interval of follow-up by using inverse regression analysis (P < 0.001; R(2) = 0.60). Controlling for duration of APAC episode, the interval of follow-up on RNFL thickness reduction remained significant (P < 0.001, r = -0.69). This study demonstrated an initial increase in diffuse RNFL thickness after a single APAC episode, followed by a subsequent decrease.

Quantitative assessment of structural damage in eyes with localized visual field abnormalities

Purpose To evaluate the pattern of structural damage in the macula and peripapillary retinal nerve fiber layer (RNFL) using optical coherence tomography (OCT) and scanning laser polarimetry (SLP-VCC) in glaucomatous eyes with localized visual field defects. Design Prospective, cross-sectional analysis. Methods Complete examination, automated achromatic perimetry (AAP), Stratus OCT imaging (512 A-scans) of the peripapillary retina and macula, and SLP-VCC imaging of the peripapillary RNFL were performed. Thickness values in the retinal segments associated with the visual field defect (glaucomatous segments) were compared with corresponding segments across the horizontal raphe (nonglaucomatous segments) and age-matched normal controls. Results Forty eyes of 40 patients (20 normal, 20 glaucomatous) were enrolled (mean age, 71 ± 10 years; range, 50 to 89). Mean RNFL thickness using SLP-VCC and OCT in the nonglaucomatous segments of glaucomatous eyes (54.0 ± 9.7 μm, 64.7 ± 19.0 μm) were significantly ( P = .009, <0.0001) reduced compared with the thickness measurements in the corresponding segments of age-matched normal subjects (62.5 ± 9.2 μm, 105.6 ± 19.0 μm) respectively. No significant ( P = .4) differences in the macular thickness measurements were observed between nonglaucomatous (239.0 ± 19.4 μm) and normal segments (243.5 ± 15.0 μm). Compared with age-matched controls, RNFL thickness in the nonglaucomatous segment was abnormal in 15 of 20 patients (75%) with SLP-VCC and in 18 of 20 patients (90%) with OCT. Macular thickness in the nonglaucomatous segment was abnormal in 11 of 20 patients (55%). Conclusions Diffuse RNFL and retinal ganglion cell loss is present in eyes with localized visual field abnormalities. Detection of localized changes in macular thickness is limited by measurement overlap among normal and glaucomatous eyes.

Retinal nerve fiber loss pattern in high-tension glaucoma by optical coherence tomography.

To identify the pattern of retinal nerve fiber layer thinning in high-tension primary chronic open-angle glaucoma (HT-PCOAG) using optical coherence tomography. Retinal nerve fiber layer thickness was assessed with optical coherence tomography in 68 healthy controls and 68 age- and refractive error-matched patients with HT-PCOAG were recruited. Patients were divided into 3 subgroups according to their visual field mean deviation: early (> -3 dB), moderate (-3 to -7 dB), and moderately advanced (-7 to -15 dB). Retinal nerve fiber layer thickness values in inferotemporal and superotemporal regions were significantly lower in all groups of glaucomatous eyes than in healthy eyes (P<0.001). Inferotemporal thickness values were significantly lower than the superotemporal thickness values (P<0.001) in the early glaucomatous stage, but not significantly so in moderate and moderately advanced stages. Besides a diffuse retinal nerve fiber layer defect, a localized defect may present in the inferotemporal region in early-stage HT-PCOAG. These results also suggest that optical coherence tomography shows promise in providing quantitative data about the location and extent of retinal nerve fiber layer injury in glaucoma, and the findings are consistent with previous knowledge.