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Purpose: Optic nerve head (ONH) evaluation plays a key role in differentiating normal from glaucomatous disk. Thinning of the inferior neuroretinal rim (NRR) has been noted in early glaucoma. However, NRR thickness in different quadrants appears to depend on various factors including central retinal vessel trunk exit (CRVT) position. We evaluated ocular parameters that determined the NRR thickness in the different quadrants of normal eyes. Methods: Retrospective review of demographic and ocular data from 773 eyes of 388 subjects with normal ONH over one year was undertaken. Results: Nearly 54% were males, and the mean age was 43.2 years. The CRVT exit was central in 50% (773). The common site for noncentral CRVT was superotemporal (ST) [37%, 141/384] followed by inferotemporal (IT) [35%, 135/384]. With noncentral CRVT, the probability that the inferior, superior, nasal and temporal (ISNT) rule was not followed was 1.42 times (P < 0.001). The thinnest rim quadrant (TRQ) was mostly ST (69%) irrespective of CRVT location. The TRQ was IT in 40% when CRVT was noncentral and 82% with IT CRVT exit. With noncentral CRVT, round disks favored noncompliance [132 (54.1%), odds ratio (OR) 2.56] with the ISNT rule. The OR of noncompliance with the ISNT rule increases 1.89 times with inferonasal CRVT and 1.22 times with a unit increase in the axial length. Conclusion: TRQ was IT in IT CRVT, and noncompliance with the ISNT rule was observed with large disks, longer axial length, and noncentral CRVT. This implies that despite the ISNT rule being violated these eyes do not have optic nerve pathology and should not be subjected to unnecessary diagnostic tests. [ABSTRACT FROM AUTHOR]

Purpose: Optic nerve head (ONH) evaluation plays a key role in differentiating normal from glaucomatous disk. Thinning of the inferior neuroretinal rim (NRR) has been noted in early glaucoma. However, NRR thickness in different quadrants appears to depend on various factors including central retinal vessel trunk exit (CRVT) position. We evaluated ocular parameters that determined the NRR thickness in the different quadrants of normal eyes. Methods: Retrospective review of demographic and ocular data from 773 eyes of 388 subjects with normal ONH over one year was undertaken. Results: Nearly 54% were males, and the mean age was 43.2 years. The CRVT exit was central in 50% (773). The common site for noncentral CRVT was superotemporal (ST) [37%, 141/384] followed by inferotemporal (IT) [35%, 135/384]. With noncentral CRVT, the probability that the inferior, superior, nasal and temporal (ISNT) rule was not followed was 1.42 times (P < 0.001). The thinnest rim quadrant (TRQ) was mostly ST (69%) irrespective of CRVT location. The TRQ was IT in 40% when CRVT was noncentral and 82% with IT CRVT exit. With noncentral CRVT, round disks favored noncompliance [132 (54.1%), odds ratio (OR) 2.56] with the ISNT rule. The OR of noncompliance with the ISNT rule increases 1.89 times with inferonasal CRVT and 1.22 times with a unit increase in the axial length. Conclusion: TRQ was IT in IT CRVT, and noncompliance with the ISNT rule was observed with large disks, longer axial length, and noncentral CRVT. This implies that despite the ISNT rule being violated these eyes do not have optic nerve pathology and should not be subjected to unnecessary diagnostic tests.

Purpose: To assess topographic characteristics of the optic nerve head (ONH) and retinal nerve fibre layer (RNFL) and study the effect of ocular and physiological factors on them in a middle‐aged population. Methods: A 1552‐person randomised sample from Northern Finland population aged 45–49 was examined. Laser scanning tomography and optical coherency tomography were performed to obtain measurements for ONH and RNFL morphology. Measurements of the RNFL included global thickness and the six zones used in automated structure–function analysis (S–F analysis). Influence of central corneal thickness (CCT), refractive correction, intraocular pressure (IOP), anterior chamber angle, gender, blood pressure, height, weight and body mass index (BMI) on tomographic data was analysed. Results: The optic disc area had a strong correlation with all other parameters of ONH morphology (R = 0.261 to 0.706) as did spherical equivalent (R = −0.280 to 0.280). The correlations between ONH and RNFL measurements were weaker (R = 0.057 to 0.180). Gender, CCT, anterior chamber angle, blood pressure, height and BMI had statistically significant, yet feeble, correlations with a number of ONH parameters. Conclusion: Other than spherical equivalent, the studied anatomical and physiological attributes had little predictive value on the ONH morphology. The optic disc area itself had a significant effect on other measurements of ONH tomography and should be taken into consideration when the thresholds for normal ONH morphology are calculated. [ABSTRACT FROM AUTHOR]

Purpose: The optic nerve head (ONH) is a part of the brain that can be evaluated through the transparent medium of the eye. The purpose of this study was to explore the possible correlations among the properties of the optic nerve head, maternal factors during pregnancy and neonatal parameters in a randomized sample of a birth cohort. Methods: The Northern Finland 1966 Birth Cohort has been prospectively monitored since their antenatal period. Data on pregnancy and neonatal period were collected during gestation and right after birth in 1966. A randomized sample of 3070 subjects underwent an ophthalmic assessment at the age of 46–48 years. The examination protocol included scanning laser ophthalmoscopy with the Heidelberg Retina Tomograph. The ophthalmological parameters assessed were the disc area and the neuroretinal rim volume of the ONH. Results: We found that chronic pulmonary disease of the mother (p = 0.007), the number of gestational weeks (p = 0.030) and the mother's highest measured systolic blood pressure (p = 0.035) during pregnancy had a statistically significant effect on the disc area. Smaller disc size was associated with pulmonary disease and early gestation. There was a significant difference in rim volume between genders (p < 0.001). Women had larger neuroretinal rim volumes compared to men. Conclusion: In this population‐based study, the vast majority of antenatal and neonatal factors showed no correlation with optic disc area or rim volume. Furthermore, even the factors with statistically significant correlation with ONH morphology had limited predictive value. [ABSTRACT FROM AUTHOR]

Glaucoma is a leading cause of irreversible vision loss that gradually damages the optic nerve. In ophthalmic fundus images, measurements of the cup to optic disc (CD) ratio, CD area ratio, neuroretinal rim to optic disc (RD) area ratio, and rim thickness are key measures to screen for potential glaucomatous damage. We propose an automatic method using deep learning algorithms to segment the optic disc and cup and to estimate the key measures. The proposed method comprises three steps: The Region of Interest (ROI) (location of the optic disc) detection from a fundus image using Mask R-CNN, the optic disc and cup segmentation from the ROI using the proposed Multiscale Average Pooling Net (MAPNet), and the estimation of the key measures. Our segmentation results using 1099 fundus images show 0.9381 Jaccard Index (JI) and 0.9679 Dice Coefficient (DC) for the optic disc and 0.8222 JI and 0.8996 DC for the cup. The average CD, CD area, and RD ratio errors are 0.0451, 0.0376, and 0.0376, respectively. The average disc, cup, and rim radius ratio errors are 0.0500, 0.2257, and 0.2166, respectively. Our method performs well in estimating the key measures and shows potential to work within clinical pathways once fully implemented. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate the optic disc morphology in primary angle-closure glaucoma (PACG) versus primary open-angle glaucoma (POAG) in South Indians. Methods: A total of 60 patients (60 eyes) with PACG and 52 patients (52 eyes) with POAG were included in a cross-sectional observational study. The glaucoma diagnosis was based on a glaucomatous appearance of the optic disc correlating with visual field defects. The glaucoma was graded as early, moderate, or severe, depending upon perimetric loss. All patients underwent an ophthalmic evaluation, including visual field examination and planimetric analysis of 30° stereoscopic color optic disc photographs. Results: The POAG and PACG groups did not differ significantly in a disc or rim area, rim width, and frequencies of disc hemorrhages or rim notches. However, early POAG group (n = 15) had a significantly deeper cup depth (P = 0.01), larger beta zone (P = 0.01), and a higher frequency of localized retinal nerve fiber layer (RNFL) defects (P = 0.02) than early PACG (n = 20). Conclusion: In the early stage of the disease, POAG compared to PACG may be characterized by deeper disc cupping, a larger beta zone of peripapillary atrophy, and a higher frequency of localized RNFL defects. Such differences in early glaucoma may suggest differences in pathophysiology in POAG and PACG.

Purpose: The aim of this study was to investigate the optic disc morphology in primary angle-closure glaucoma (PACG) versus primary open-angle glaucoma (POAG) in South Indians.Methods: A total of 60 patients (60 eyes) with PACG and 52 patients (52 eyes) with POAG were included in a cross-sectional observational study. The glaucoma diagnosis was based on a glaucomatous appearance of the optic disc correlating with visual field defects. The glaucoma was graded as early, moderate, or severe, depending upon perimetric loss. All patients underwent an ophthalmic evaluation, including visual field examination and planimetric analysis of 30° stereoscopic color optic disc photographs.Results: The POAG and PACG groups did not differ significantly in a disc or rim area, rim width, and frequencies of disc hemorrhages or rim notches. However, early POAG group (n = 15) had a significantly deeper cup depth (P = 0.01), larger beta zone (P = 0.01), and a higher frequency of localized retinal nerve fiber layer (RNFL) defects (P = 0.02) than early PACG (n = 20).Conclusion: In the early stage of the disease, POAG compared to PACG may be characterized by deeper disc cupping, a larger beta zone of peripapillary atrophy, and a higher frequency of localized RNFL defects. Such differences in early glaucoma may suggest differences in pathophysiology in POAG and PACG. [ABSTRACT FROM AUTHOR]

Glaucoma is a leading cause of irreversible vision loss that gradually damages the optic nerve. In ophthalmic fundus images, measurements of the cup to optic disc (CD) ratio, CD area ratio, neuroretinal rim to optic disc (RD) area ratio, and rim thickness are key measures to screen for potential glaucomatous damage. We propose an automatic method using deep learning algorithms to segment the optic disc and cup and to estimate the key measures. The proposed method comprises three steps: The Region of Interest (ROI) (location of the optic disc) detection from a fundus image using Mask R-CNN, the optic disc and cup segmentation from the ROI using the proposed Multiscale Average Pooling Net (MAPNet), and the estimation of the key measures. Our segmentation results using 1099 fundus images show 0.9381 Jaccard Index (JI) and 0.9679 Dice Coefficient (DC) for the optic disc and 0.8222 JI and 0.8996 DC for the cup. The average CD, CD area, and RD ratio errors are 0.0451, 0.0376, and 0.0376, respectively. The average disc, cup, and rim radius ratio errors are 0.0500, 0.2257, and 0.2166, respectively. Our method performs well in estimating the key measures and shows potential to work within clinical pathways once fully implemented.

Background and objective: Assessment of optic disc morphology is essential in diagnosis and management of visual impairment. The aim of this study was to evaluate associations between optic disc morphometric parameters, i.e., size and shape, and age, gender, and ocular axial length in normal and glaucomatous eyes based on time-domain optical coherence tomography image analysis.Materials and methods: It was a case–control study of 998 normal and 394 eyes with primary open angle glaucoma that underwent an ophthalmological examination and time-domain optical coherence topography scanning. Areas and shapes of the disc, cup, and neuroretinal rim were analyzed.Results: The shape of the optic disc did not differ between the study groups, i.e., normal and glaucomatous case groups, but the disc area of the primary open angle glaucoma group was significantly larger. The shape of the small disc was significantly different, but the shape of the medium and the large disc did not differ between the study groups. The central area of the disc, i.e., cup area was significantly larger in the case group and its shape was significantly different between the study groups. No significant differences in the area of the cup and its shape, nerve fibers on the edge of the disc, i.e., neuroretinal rim area, were found between the study groups of the small discs. There were significant associations between age, gender, and ocular axial length and morphometric parameters of the optic disc.Conclusions: Informative results with regard to the size and shape due to various ocular characteristics between the healthy control group and patients suffering with primary open angle glaucoma were obtained. Both study groups were significant in size, which makes the findings interesting and important contribution in the field.

Purpose: To determine the frequency with which retinal tissues other than the nerve fibre layer, hereafter referred to as protruded retinal layers (PRL), are a component of optical coherence tomography (OCT) neuroretinal rim measurements. Methods: Ninety healthy (30 White, Black and Japanese, respectively) subjects were included in the study. A radial scan pattern (24 B‐scans centred on Bruch's membrane opening [BMO]) was used. For each of the 48 minimum rim width (MRW) measurement points, we determined whether PRL were present, absent or indeterminate. When present, the proportion of PRL within the MRW was quantified. Results: Protruded retinal layers were present in 503 (11.6%), absent in 3805 (88.1%) and indeterminate in 12 (0.3%) measurement points. Overall, 69 (76.6%) subjects had ≥1 points with PRL, with White subjects having the highest frequency and Japanese the lowest (29 [97%] and 18 [60%], respectively; p < 0.01). PRL were present in one‐third of points in the temporal sector, but ≤5% in other sectors. When present, the median PRL thickness was 53.0 (interquartile range [IQR]: 33.0 to 78.5) μm, representing 20.6 (IQR: 13.0 to 28.5)% of MRW. Globally, the median PRL thickness comprised 1.3 (IQR: 0.2 to 3.5)% of the MRW; however, in the temporal sector, it exceeded 30% of MRW in some subjects. Conclusions: Protruded retinal layers are a component of MRW measurements in most normal subjects, occurring in almost 12% of all measurement points analysed. There were racial variations in the presence of PRL and a significantly higher frequency of PRL in the temporal sector. [ABSTRACT FROM AUTHOR]

Purpose To investigate the reproducibility of Bruch's membrane opening minimum rim width ( BMO- MRW) and retinal nerve fibre layer thickness ( RNFLT) measurements using spectral domain optical coherence tomography ( SD- OCT). Additionally, to investigate the reproducibility of BMO area measurements and fovea to BMO centre (Fo BMO) angle. Methods Participants were healthy subjects ( n = 30) and patients with glaucoma ( n = 26). One eye of each participant was scanned to obtain optic nerve head (24 radial B-scans) and peripapillary (one circular B-scan) images by three independent examiners. Additionally, one examiner imaged each participant three times on the same day. Intra- and interobserver reproducibilities were estimated by within-subject standard deviation ( SW) and coefficient of variation ( COV). Spearman's rank correlation coefficient was used to test the correlation between the magnitude of the parameter and its standard deviation. Results The global BMO- MRW COVs (%) in healthy/glaucoma subjects were 0.87/1.34 and 1.28/3.13 for intra- and interobserver analyses, respectively, and the corresponding global RNFLT figures were 1.50/2.10 and 2.04/2.87. Global mean BMO- MRW and RNFLT showed no correlation with their respective standard deviations. The reproducibilities of BMO area and Fo BMO angle were excellent and similar between the groups. Conclusion The reproducibilities of BMO- MRW, BMO area measurements and Fo BMO angle were excellent in both healthy subjects and patients with glaucoma. Bruch's membrane opening minimum rim width (BMO-MRW) reproducibility is comparable to that of RNFLT measurements. [ABSTRACT FROM AUTHOR]

Glaucoma originally meant "clouded", in Greek.The term glaucoma refers to a group of diseases that have in common characteristic optic neuropathy with associated visual field loss for which elevated intraocular pressure is one of the primary risk factor. The purpose of the study is to correlate the clinically diagnosed cases of glaucoma suspect with the Humphrey Field Analyzer (HFA). Fifty cases of glaucoma suspect who attended the glaucoma clinic of Nepal Eye Hospital Tripureswor, Kathmandu, Nepal and who meets at least two criteria, among the four types of glaucoma suspects were advised for the HFA for the study. In this study out of 50 patient, 36 (72%) patients had normal visual field. 14 (28%) patients had thinning of the neural retinal rim (NRR) in both eyes. The significant relation with thinning of neural retina rim and glaucomatous hemifield test was found in the study. Journal of College of Medical Sciences-Nepal,2012,Vol-8,No-1, 23-28 DOI: http://dx.doi.org/10.3126/jcmsn.v8i1.6822

Background: The Heidelberg Retina Tomograph (HRT) is a commonly-used clinical instrument for glaucoma diagnosis; however, the repeatability of the two most commonly used analysis tools, Moorfield regression analysis (MRA) and 'glaucoma probability score' (GPS) is not known and could have significant implications for patients at risk or suspected of developing glaucoma. Thus, the intra-visit repeatability of the HRT3 (an objective measure of instrument-induced variability) was investigated in a glaucoma suspect cohort.Methods: Two repeat 15° × 15° optic nerve head scans were taken from 164 eyes of 84 patients using the HRT (HRT3, software version 3) during a single visit. The variability of global and sectoral rim area, rim volume and GPS were analysed with and without image alignment using SPSS 22.0. Repeatability was evaluated as absolute difference between the two measurements.Results: Repeatability of the global rim area, rim volume and GPS were high with and without image registration. Variability increased by a small, yet significant amount without image alignment (p < 0.001 to p = 0.002). This increase was more prominent for sectoral analysis with the exception of the rim area and volume in the temporal sector (p = 0.034 to p < 0.001). Increase in the variability of the GPS was also significant (p < 0.001).Conclusion: HRT3 demonstrated high short-term repeatability, which significantly improved with image registration for all global measurements. Sectoral analysis demonstrated higher repeatability with image registration for some of the sectors in rim area and volume analysis and all sectors for the GPS. Therefore, depending upon the assessed parameters, image registration may play a significant role in the interpretation of results in glaucoma suspects. [ABSTRACT FROM AUTHOR]

Purpose: To compare the confocal laser tomographic scanning evaluation with photographic measurements of the optic nerve head in a South Indian population. Methods: The prospective comparative clinical non-interventional epidemiologic study included 62 subjects (62 eyes) forming a population-based sample, selected randomly. Mean age was 47.2 ± 8.9 years, mean refractive error measured was -0.17 ± 1.10 diopter (range, - 4.50 to + 2.50 diopter). Confocal laser scanning tomographic images on Heidelberg Retina Tomograph (HRT) and colour optic disc photographs were morphometrically analysed and compared. Main outcome measures were morphologic optic disc parameters. Results: The optic disc area measurements were significantly smaller (p < 0.001) in the HRT technique than in the photographic method. In contrast, the HRT as compared to the photographic measurements showed significantly (p < 0.001) larger values for the relative width and relative area of the neuroretinal rim. The differences in measurements between both methods were maximum in the nasal part (p < 0.001) of the optic disc and minimum in the temporal disc region. Conclusion: In normal eyes of South Indians, neuroretinal rim measurements by the HRT and expressed as percentage of disc size measurements are significantly larger than rim measurements on disc photographs.

Purpose To examine associations between body mass index, neuroretinal rim area and retinal nerve fibre layer cross-sectional area ( RNFLCRA) in a population-based setting. Methods The Central India Eye and Medical Study is a population-based study performed in a rural region of Central India. The study included 4711 subjects (aged 30 + years). A detailed ophthalmic and medical examination was performed. Inclusion criteria for this study were an intra-ocular pressure ≤21 mmHg, open anterior chamber angles and an axial length ≤26.5 mm. Neuroretinal rim area and RNFLCRA were measured by confocal laser scanning tomography. Results The study included 3959 subjects fulfilling the inclusion criteria. Larger neuroretinal rim area (mean: 1.63 ± 0.32 mm2) was significantly (p = 0.004) associated with a higher body mass index after adjusting for larger disc area (p < 0.001), younger age (p < 0.001), lower intraocular pressure (p < 0.001), and hyperopic refractive error (p < 0.001). Larger retinal nerve fibre layer cross-sectional area (mean:1.29 ± 0.39 mm2) was significantly associated with higher body mass index (p = 0.001) after adjusting for younger age (p < 0.001), shorter axial length (p < 0.001), larger optic disc area (p < 0.001), taller body height (p < 0.001) and male gender (p = 0.04). Conclusions In a rural Central Indian population, neuroretinal rim area and RNFLCRA as surrogates of the optic nerve fibres were related to a higher body mass index. Because body mass index is associated with cerebrospinal fluid pressure, the higher cerebrospinal fluid pressure may be associated with a larger neuroretinal rim area. It may vaguely point towards an association between cerebrospinal fluid pressure and glaucomatous optic neuropathy. [ABSTRACT FROM AUTHOR]

Objective: To find out the patterns the optic disc changes associated with primary open angle glaucoma (POAG). Methodology: This descriptive study was conducted at Ophthalmology department, Hayatabad Medical Complex Peshawar from 1st January to 31st December 2009. All patients with diagnosed POAG, above the age of 30 years, having no lens or media opacity and ocular co-morbidity, were examined thoroughly for patterns of optic disc changes associated with POAG. Frequencies and percentages of the contour of neuroretinal rim, appearance of nerve fiber layer, presence of optic disc hemorrhages, colour of optic nerve head was noted. Descriptive statistics for disc were calculated for Vertical disc diameter (VDD), Cup/disc ratio (CDR), and Rim Disc Ratio (RDR). Results: Two hundred patients with POAG were included. Diffuse thinning and localized notching in the neuroretinal rim was noted in 188 (94%) and 86 (43%) patients, respectively. Optic disc hemorrhage, Optic disc pallor and Optic disc atrophy was seen in 80 (40%), 127 (63.5%) and 15 (7.5%) cases, respectively. Mean VDD was 1.76mm in both right and left eyes. Mean vertical and horizontal CDR was 0.73 and 0.57 in the right and 0.765 and 0.611 in the left eye, respectively. Mean vertical and horizontal RDR was 0.451 and 0.543 in the right and 0.368 and 0.486 in the left eyes, respectively. Conclusion: Majority of the patients showed changes in measurements of neuroretinal rim, so emphasis should be placed on the examination of neuroretinal rim in all patients of POAG. [ABSTRACT FROM AUTHOR]

Background: Corneal hysteresis (CH) has been associated with visual field damage in glaucoma and is related to the velocity of perimetric glaucoma progression. We undertook this investigation to determine whether CH is associated with structural markers of glaucoma damage on spectral domain optical coherence tomography (SD-OCT). Methods: In this retrospective study, 131 patients under glaucoma evaluation were evaluated with SD-OCT (Cirrus; Carl Zeiss Meditec, Dublin, CA) and had CH measurements with the ocular response analyzer (Reichert, Inc., Buffalo, NY). Pearson and partial correlation adjusting for age were preformed to examine the association between CH and variables of interest. Generalized estimating equations were used to construct simple and multiple linear models. Results: While Pearson correlations were modest overall, CH best correlated with mean deviation (MD; r = 0.19) followed by average retinal nerve fiber layer (RNFL) thickness ( r = 0.18) and vertical cup to disc ratio ( r = −0.11) in the open angle glaucoma group. In univariable models, CH varied as a function of MD ( ß = 0.1, 95 % CI 0.03, 0.1; p < 0.001) and of average RNFL thickness ( ß = 0.2, 95 % CI 0.1, 0.4; p = 0.001). In a multivariable analysis including MD, age, average RNFL thickness, and glaucoma status, MD ( p = 0.001) and age ( p < 0.001) retained significant associations with CH. Conclusions: In patients under evaluation and treatment for glaucoma, CH was more closely related to visual field MD than to structural markers of glaucoma damage as measured by SD-OCT. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the impact of corneal hysteresis (CH) as a risk factor for progressive neuroretinal rim loss in glaucoma, as measured by spectral-domain OCT of the Bruch's membrane opening minimum rim width (MRW)., Design: Prospective, observational cohort study., Participants: The study group included 118 eyes of 70 subjects with glaucoma. The average follow-up time for the cohort was 3.9 ± 1.3 years, with an average of 6.4 ± 2.0 spectral-domain OCT tests, ranging from 4 to 12., Methods: Corneal hysteresis measurements were acquired at baseline using the Ocular Response Analyzer (Reichert Instruments). Linear mixed models were used to investigate the relationship between the rates of MRW loss and baseline CH. Multivariable analyses adjusted for other putative predictive factors for progression, including mean intraocular pressure (IOP), central corneal thickness (CCT), age, race, and baseline disease severity., Main Outcome Measures: Effects of CH on the rate of MRW change over time., Results: Corneal hysteresis had a significant effect on rates of MRW progression over time. Each 1-mmHg lower CH was associated with -0.38 μm/year faster MRW loss (95% confidence interval [CI], -0.70 to -0.06; P = 0.019), after adjustment for other predictive factors. The mean IOP was also significantly associated with progression, with -0.35 μm/year (95% CI, -0.47 to -0.23 μm/year) faster MRW change for each 1-mmHg higher pressure (P < 0.001). In the analysis of predictive strength, the mean IOP was the strongest predictive factor (R 2  = 23%), followed by CH (R 2  = 14%) and baseline disease severity (R 2  = 6%). Central corneal thickness explained only 3% of the variability in slopes of change in global MRW., Conclusions: Lower CH measurements were associated with faster loss of the neuroretinal rim in glaucoma, as measured by MRW. The predictive ability of CH was superior to that of CCT. These findings suggest that CH is an important parameter to be considered in assessing the risk of glaucoma progression., (Copyright © 2022 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Background The aim here was to investigate whether optic nerve head ( ONH) parameters or retinal nerve fibre layer ( RNFL) thickness correlate with age or disc area and whether the neuroretinal rim correlates with RNFL thickness. Methods This cross-sectional study enrolled 133 healthy subjects and analysed one randomly selected eye of each subject. All measurements of ONH parameters (including neuroretinal rim, disc and cup areas and cup-to-disc ratios) and RNFL thickness (global and quadrants) were taken by a single experienced operator using optical coherence tomography ( OCT). Results Of the rim parameters analysed, average nerve width (the height of the nerve fibre bundle) was independent of age or disc area (p > 0.05). Disc area correlated positively with cup area (p < 0.05) but not with cup-to-disc ratios (p > 0.05). Of the RNFL thickness measurements analysed, temporal RNFL was independent of both age and disc area (p > 0.05). According to the analysis of the correlation between RNFL thickness and neuroretinal rim, global or non-temporal RNFL correlated positively with horizontal integrated rim width (p < 0.05, F > 4.000) and temporal RNFL was independent of all rim parameters (p > 0.05, F < 4.000). Conclusion Aging effect on neuroretinal rim loss or RNFL thickness change is non-uniform, and age is not a constant confounder when using OCT. The temporal RNFL is independent of age, disc area and neuroretinal rim. [ABSTRACT FROM AUTHOR]

Background: The aim of this work is to prospectively assess the relationship between trans-laminar cribrosa pressure difference and neuroretinal rim area as morphologic surrogate of glaucomatous optic nerve damage. Methods: The study included 22 patients with high-pressure glaucoma, 13 patients with normal-pressure glaucoma, and 17 subjects with ocular hypertension. All participants underwent a standardized ophthalmologic examination including confocal laser scanning tomography of the optic nerve head and computerized perimetry and a neurologic examination including measurement of the lumbar cerebrospinal fluid (CSF) pressure. The trans-lamina cribrosa pressure difference was calculated as difference of intraocular pressure minus lumbar CSF pressure. Results: Neuroretinal rim area ( p = 0.006; correlation coefficient r = −0.38) and mean visual field defect ( p = 0.008; r = 0.38) were significantly associated with trans-lamina cribrosa pressure difference. The probability of error was lower (i.e., the p value were lower) and the correlation coefficients were higher for the associations between rim area/visual field defect with trans-lamina cribrosa pressure difference than for the associations between rim area/visual field defect and intraocular pressure or lumbar CSF pressure. Conclusions: The trans-lamina cribrosa pressure difference as the difference of intraocular pressure minus the lumbar CSF pressure was the main pressure parameter associated with the amount of glaucomatous optic nerve damage. This may suggest that the CSF pressure as trans-lamina cribrosa counter pressure against the intraocular pressure may play some role in the pathogenesis of glaucomatous optic neuropathy. [ABSTRACT FROM AUTHOR]

Automatic retinal image analysis is emerging as an important screening tool for early detection of eye diseases. Glaucoma is one of the most common causes of blindness. The manual examination of optic disk (OD) is a standard procedure used for detecting glaucoma. In this paper, we present an automatic OD parameterization technique based on segmented OD and cup regions obtained from monocular retinal images. A novel OD segmentation method is proposed which integrates the local image information around each point of interest in multidimensional feature space to provide robustness against variations found in and around the OD region. We also propose a novel cup segmentation method which is based on anatomical evidence such as vessel bends at the cup boundary, considered relevant by glaucoma experts. Bends in a vessel are robustly detected using a region of support concept, which automatically selects the right scale for analysis. A multi-stage strategy is employed to derive a reliable subset of vessel bends called r-bends followed by a local spline fitting to derive the desired cup boundary. The method has been evaluated on 138 images comprising 33 normal and 105 glaucomatous images against three glaucoma experts. The obtained segmentation results show consistency in handling various geometric and photometric variations found across the dataset. The estimation error of the method for vertical cup-to-disk diameter ratio is 0.09/0.08 (mean/standard deviation) while for cup-to-disk area ratio it is 0.12/0.10. Overall, the obtained qualitative and quantitative results show effectiveness in both segmentation and subsequent OD parameterization for glaucoma assessment. [ABSTRACT FROM PUBLISHER]

Glaucoma is the second leading ocular disease causing blindness due to gradual damage to the optic nerve and resultant visual field loss. Segmentations of the optic disc cup and neuroretinal rim can provide important parameters for detecting and tracking this disease. The purpose of this study is to describe and evaluate a method that can automatically segment the optic disc cup and rim in spectral-domain 3-D OCT (SD-OCT) volumes. Four intraretinal surfaces were segmented using a fast multiscale 3-D graph search algorithm. After surface segmentation, the retina in each 3-D OCT scan was flattened to ensure a consistent optic nerve head shape. A set of 15 features, derived from the segmented intraretinal surfaces and voxel intensities in the SD-OCT volume, were used to train a classifier that can determine which A-scans in the OCT volume belong to the background, optic disc cup and rim. Finally, prior knowledge about the shapes of the cup and rim was incorporated into the system using a convex hull-based approach. Two glaucoma experts annotated the cup and rim area using planimetry, and the annotations of the first expert were used as the reference standard. A leave-one-subject-out experiment on 27 optic nerve head-centered OCT volumes (14 right eye scans and 13 left eye scans from 14 patients) was performed. Two different types of classification methods were compared, and experimental results showed that the best performing method had an unsigned error for the optic disc cup of 2.52 ±0.87 pixels (0.076 ±0.026 mm) and for the neuroretinal rim of 2.04 ± 0.86 pixels (0.061 ± 0.026 mm). The interobserver variability as indicated by the unsigned border positioning difference between the second expert observer and the reference standard was 2.54 ± 1.03 pixels (0.076 ± 0.031 mm for the optic disc cup and 2.14 ± 0.80 pixels (0.064 ± 0.024 mm for the neuroretinal rim. The unsigned error of the best performing method was not significantly different (p > 0.2) from the interobserver variability. [ABSTRACT FROM AUTHOR]

AimsTo evaluate the relevance of the ISNT rule with reference to the optic nerve head, in differentiating normal and early glaucoma eyes and neuroretinal rim (NRR) area ratios as measures of glaucomatous optic neuropathy by confocal scanning laser ophthalmoscopy (Heidelberg retina tomography (HRT) II).MethodsThe study included 136 control eyes and 63 eyes of early primary open-angle glaucoma. Each patient underwent a complete ophthalmic examination, HRT II (software 2.01) and achromatic automated perimetry using the Humphrey field analyzer Full threshold program 30-2 or 24-2. Topographic HRT parameters (disc area and rim area) were compared between the groups. To assess the statistical significance of differences between the study groups, the Student's t-test was used.ResultsThe ISNT rule was applicable in 71% of normal eyes and 68% of early glaucoma eyes. The superior to inferior area ratio was 0.96±0.01 in the normal group and 0.90±0.02 in the glaucoma group. There was a loss of approximately a quarter of the NRR in the inferotemporal and superotemporal quadrants. The inferonasal sector showed the least loss of NRR (4.34%).ConclusionThe inferior NRR is marginally wider than the superior NRR in about 2/3 of normal eyes, but could not be clinically appreciated in many of these. The characteristic configuration of a normal optic disc with the rim width being greatest in the inferior disc region followed by the superior disc region was maintained even in most patients with early glaucoma.Eye (2008) 22, 819–824; doi:10.1038/sj.eye.6702798; published online 13 April 2007 [ABSTRACT FROM AUTHOR]

PurposeTo determine peripapillary atrophy in elderly Chinese in an urban and rural regions of Beijing.MethodsThe Beijing Eye Study a population-based, cross-sectional cohort study, included 4439 subjects out of 5324 subjects who were asked to participate (response rate 83.4%). Mean age was 56.2±10.6 years (range, 40–101 years). Colour optic disc photographs (30°) were morphometrically examined. Peripapillary atrophy was divided into alpha zone and beta zone.ResultsOptic disc photographs were available for 4027 (90.7%) subjects. Alpha zone and beta zone, respectively, were present in 2867 (71.2%) subjects and 802 (19.9%) subjects, respectively, measuring 0.52±0.64 mm2 and measuring 0.46±1.82 mm2. Both zones were significantly widest and found significantly (P<0.001) most often in the temporal peripapillary region, followed by the temporal inferior region, the temporal superior region, and finally the nasal region. Size of both zones was significantly correlated with optic disc size (P<0.001), age (P<0.001), and myopic refractive error (P<0.001). Both zones increased significantly with decreasing uncorrected visual acuity (P<0.001) and decreasing best-corrected visual acuity (P<0.001). They did not vary significantly (P=0.10; and P=0.78) between male and female subjects. In multivariate analysis, the relationships between both zones and age, myopic refractive error, disc size, and uncorrected and best-corrected visual acuity remained statistically significant (P<0.001).ConclusionsAlpha zone and beta zone of peripapillary atrophy, respectively, occur in about 70 and 20%, respectively, of elderly Chinese. As peripapillary atrophy changes in glaucomatous optic neuropathy, these normative data may be helpful for glaucoma detection.Eye (2008) 22, 261–266; doi:10.1038/sj.eye.6702601; published online 22 September 2006 [ABSTRACT FROM AUTHOR]

Purpose: To identify the investigator effect in the analysis results of Heidelberg retinal flowmetry (HRF) images when pixel-by-pixel analysis is performed. Methods: Thirty-two of 732 HRF images were randomly selected from a population-based study. Pixel-by-pixel analysis was performed by two trained masked graders in the following way: a square window of 40 × 40 pixels or two windows of 30 × 30 pixels or four windows of 20 × 20 pixels free from blood vessels at the peripapillary retina were identified. Using a 1 × 1-pixel window, the grader performed pointwise analysis according to a specific protocol. The analysis process was performed by each observer three times (A, B, C) at 1-week intervals. The percentage of pixels with < 1 arbitrary unit of flow (zero flow), the 10th, 25th, 50th, 75th and 90th percentiles and mean flow values were calculated. The difference between the results of analyses B−A and C−A for all HRF parameters was estimated using the Wilcoxon signed rank test. Mixed-effect regression models were also used after controlling for grader effect and correlation within subjects. Results: There was no statistically significant difference between the results of analyses B−A and C−A or for any parameter in the mixed-effect regression models. Intraclass correlation was 0.9665 for the percentage of zero flow pixels. Conclusions: Pixel-by-pixel analysis of HRF images by trained graders remains a highly reproducible method. No grader effect was found. If a precise protocol is followed, the results are independent of the exact placement of the analysis windows and the pointwise analysis of the identified and mapped retinal tissue. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate whether iris colour influences size and shape of the optic nerve head and risk for glaucoma progression. Methods: The hospital-based observational study included 1973 eyes of 1012 Caucasian subjects with ocular hypertension or chronic open-angle glaucoma. For all patients, colour stereo optic disc photographs were evaluated, and corneal pachymetry and achromatic perimetry were performed. Main outcome measures were optic nerve head parameters, the development or progression of visual field defects and iris colour. Results: In most of the study groups, size of the optic disc, neuroretinal rim, alpha zone and beta zone of parapapillary atrophy, retinal vessel diameter and central corneal thickness did not differ significantly between eyes with blue, green, brown and mixed iris colour. In the normal-pressure glaucoma group, neuroretinal rim area was smallest in the population with mixed-coloured eyes and largest in the group of eyes with brown irides ( P = 0.001 after correction for inter-eye dependency and multiple testing). For the ocular hypertensive subjects and glaucoma patients with follow-up examinations, the rate of development or progression of glaucomatous visual field loss was not significantly associated with iris colour ( P = 0.060). Conclusions: In Caucasian subjects, iris colour does not have a major association with the size of the optic nerve head structures, central corneal thickness and retinal arterial diameter. In Caucasian patients with ocular hypertension or chronic open-angle glaucoma, an influence of iris colour on the risk for development or progression of glaucomatous visual field defects could not be confirmed. [ABSTRACT FROM AUTHOR]

Background. Optic nerve diseases, such as glaucomas, lead to changes in the intrapapillary and parapapillary region of the optic nerve head.Conclusions. These changes can be described by the following variables: size and shape of the optic disc; size, shape, and pallor of the neuroretinal rim; size of the optic cup in relation to the area of the disc; configuration and depth of the optic cup; ratios of cup to disc diameter and cup to disc area; position of the exit of the central retinal vessel trunk on the lamina cribrosa surface; presence and location of splinter-shaped hemorrhages; occurence, size, configuration, and location of parapapillary chorioretinal atrophy; diffuse and/or focal decrease of the diameter of the retinal arterioles; and visibility of the retinal nerve fiber layer (RNFL). These variables can be assessed semiquantitively by ophthalmoscopy without applying sophisticated techniques. For the early detection of glaucomatous optic nerve damage in ocular hypertensive eyes before the development of visual field loss, the most important variables are neuroretinal rim shape, optic cup size in relation to optic disc size, diffusely or segmentally decreased visibility of the RNFL, occurence of localized RNFL defects, and presence of disc hemorrhages.

Purpose: To determine the impact of glaucoma severity on rates of change of minimum rim width (MRW), peripapillary retinal nerve fiber layer (RNFL), and macular ganglion cell layer (GCL) thickness., Design: Prospective, cohort study., Methods: Glaucoma patients and healthy subjects had optical coherence tomography scans at 6-month intervals. Individual rates of change for MRW, RNFL, and GCL thickness were estimated with ordinary least-squares regression. Linear mixed-effect models were used to estimate the rate of change of each parameter and evaluate the impact of glaucoma severity (expressed by visual field mean deviation, MD) and age on these rates., Results: A total of 132 glaucoma patients and 57 healthy subjects were followed for a median of 4.3 years and 3.7 years, respectively. Healthy subjects had a statistically significant deterioration in MRW (-1.66 µm/year), RNFL (-0.46 µm/year), and GCL thickness (-0.22 µm/year). While glaucoma patients had a faster rate of change in each parameter compared with healthy subjects, only GCL thickness showed a statistically significant group difference (mean difference: -0.17 µm/year; P = .03). Older baseline age was associated with faster GCL thickness change (-0.07 µm/year; P = .03), but not other parameters. Baseline MD had no impact on the subsequent rates of change in any of the parameters., Conclusions: The rates of MRW, RNFL, and GCL thickness change were not significantly influenced by glaucoma severity at baseline; however, GCL thickness was able to statistically contrast the rate of change between healthy subjects and glaucoma patients throughout the disease spectrum., (Copyright © 2022 Elsevier Inc. All rights reserved.)

• The results of conventional measurement methods show a thinning of retinal nerve fiber layer (RNFL) thickness in myopic patients. • It is debatable whether the thinning of the RNFL in young, healthy individuals with myopia depends on the loss of ganglion cells that may be caused by myopia or on the reliability of measurement methods. • Novel methods are being developed to measure the RNFL more accurately. • This study shows that Bruch's membrane opening minimum rim width (BMO-MRW) and RNFL, acquired using anatomic positioning system (APS-RNFL) measurements in pediatric myopic individuals, are not affected by the degree of myopia as much as standard RNFL. • Standard RNFL thickness measurement results in healthy myopic children (especially greater than │-4│ diopters) may resemble RNFL thickness thinning in glaucoma. Since the new optical coherence tomography(OCT) parameters, BMO-MRW and APS-RNFL, are less affected by the degree of myopia than standard measurements, it may help us to avoid misdiagnosis of glaucoma in these individuals. It is debatable whether the decrease of retinal nerve fiber layer (RNFL) thickness in myopic people under 18 years of age is due to insufficient measurement techniques or to real physical loss of retinal ganglion cells and axons. Hence, to better understand the relationship between the degree of myopia and the neuroretinal rim (NR), we aim to investigate the NR in the eyes of healthy myopic children using the novel measurement algorithms of spectral-domain optical coherence tomography (SD-OCT). This prospective, cross-sectional study includes 378 left eyes of 378 (301 female) participants divided into three groups according to their spherical equivalent (SE) refractive error (RE) [Group-1(G1), -1.00 ≤ SE ≤ 1.00 diopters (D); Group-2 (G2), -4.00 ≤ SE < -1.00 D; Group-3 (G3), SE<-4.00 D]. All participants underwent a full ophthalmic examination, including biometric and pachymetric measurements. Standard peripapillary RNFL, as well as the novel algorithms, Bruch's membrane opening-minimum rim width (BMO-MRW), and RNFL acquired using the anatomic positioning system (APS-RNFL) were obtained by SD-OCT. Nasal, temporal, temporal-inferior, temporal-superior, nasal-inferior, nasal-superior sectors' and their general (global) averages were recorded. Rim areas and disc sizes were measured via confocal scanning laser ophthalmoscopy. Global and the six sectors' averages were recorded. G1 consisted of 141 subjects, G2 consisted of 89, and G3 consisted of 48. The sex distribution (p = 0.112) and mean age (p = 0.129) of the groups were similar. The mean global averages of the standard RNFLs were 96 ± 14.4 µ in G1, 93.8 ± 12.9 µ in G2, and 86 ± 11.8 µ in G3. The mean global averages of the APS-RNFLs were 103.9 ± 97 µ in G1, 103.3 ± 10.6 µ in G2, and 102 ± 10.6 µ in G3. The mean global averages of the BMO-MRW were 374.4 ± 57.7 µ in G1, 373.2 ± 62.2 µ in G2, and 351.9 ± 63.9 µ in G3. For the global averages, APS-RNFL and BMO-MRW did not detect any difference between the three groups (p = 0.563, p = 0.089, respectively), but the standard RNFL did (p < 0.001). Standard RNFL and APS-RNFL were found to be well correlated; however, the correlations between BMO-MRW and standard RNFL or APS-RNFL were either absent or very weak. All three methods showed weak but significant negative correlations with high myopic spherical RE, especially those in the standard RNFL. Moderately negative correlations were found between BMO-MRW and disc size in all sectors (highest in the nasal sector; r = -0.387, p < 0.001). However, there was almost no significant relationship between disc size and standard RNFL or APS-RNFL. Moderately significant negative correlations were observed between the groups categorically and standard RNFL in almost all sectors, while this was much less with APS-RNFL and was not observed in almost any sector with BMO-MRW. When evaluating the NR in healthy myopic children, it was found that, in particular, BMO-MRW and APS-RNFL are less effected by RE degree compared to standard RNFL. BMO-MRW and APS-RNFL should be used on these children to avoid the possible misdiagnosis of glaucoma. [ABSTRACT FROM AUTHOR]

Purpose: To compare onset times of glaucoma progression among different glaucoma tests: disc photography (DP), visual field (VF) testing, 2-dimensional (2D) retinal nerve fiber layer (RNFL) thickness, and 3-dimensional (3D) spectral-domain (SD) OCT neuroretinal rim measurements., Design: Prospective, longitudinal cohort study., Participants: One hundred twenty-four eyes of 124 patients with open-angle glaucoma., Methods: Over a 5-year period, 124 patients with open-angle glaucoma underwent yearly DP, VF testing, SD OCT RNFL thickness scans, and optic nerve volume scans (Spectralis; Heidelberg Engineering), all performed on the same day. From high-density optic nerve volume scans, custom-built software calculated the minimum distance band (MDB) thickness, a 3D neuroretinal rim parameter. Patients were classified as glaucoma progressors or nonglaucoma progressors using event-based analysis. Progression by DP and VF testing occurred when 3 masked glaucoma specialists unanimously concurred. Progression by RNFL and MDB thickness occurred if change of more than test-retest variability was observed. Kaplan-Meier curves were constructed to analyze time-to-progression data. Kappa Coefficients were used to measure agreement of progressing eyes among methods., Main Outcome Measures: Time to glaucoma progression among all 4 methods., Results: Global MDB thickness detected glaucoma progression in the highest percentage of eyes (52.4%) compared with DP (16.1%; P < 0.001) and global RNFL thickness (15.3%; P < 0.001). Global MDB thickness detected glaucoma progression earlier than either DP (23 months vs. 44 months; P < 0.001) or global RNFL thickness (23 months vs. 33 months; P < 0.001). Among MDB progressing eyes, 46.2% were confirmed simultaneously or later by other conventional methods. Agreement of glaucoma-progressing eyes for all 4 methods in paired fashion were slight to fair (κ = 0.095-0.300)., Conclusions: High-density 3D SD OCT neuroretinal rim measurements detected glaucoma progression approximately 1 to 2 years earlier compared with current clinically available structural tests (i.e., DP and 2D RNFL thickness measurements)., (Copyright © 2021 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Glaucoma is a characteristic optic neuropathy which associates high intra-ocular pressure, loss of visual field and structural changes of the optic disc and the peripapillary area. Optical coherence tomography (OCT) is an imagistic method of investigation that is non-invasive and repeatable. It analyses objectively the glaucomatous changes that appear in the retinal nerve fibre layer (RNFL), optic disc (neuro-retinal rim, optic cup, cup/ disc ratio). OCT is a very usefull investiogation for an early diagnoses of glaucoma and for predicting the progression rate of the disease (by make succesive measurements). [ABSTRACT FROM AUTHOR]

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Optic nerve head (ONH) neuroretinal rim thickness, quantified as minimum rim width (BMO-MRW), is a sensitive measure for assessing early glaucomatous disease. The BMO-MRW is sensitive to transient fluctuations in intraocular pressure (IOP), but the time course over which BMO-MRW decreases and recovers with changes in IOP remains unknown. The goal of this study was to investigate the dynamics of BMO-MRW changes over 2-h periods of mild or moderate IOP elevation, and subsequent recovery, in healthy non-human primate eyes. Eight non-human primates were included in the study. For each animal, in two different sessions separated by at least 2 weeks, the anterior chamber IOP of one eye was maintained at either 25 mmHg or 40 mmHg for 2 h and, subsequently, at 10 mmHg for 2 h. For the duration of anterior chamber cannulation, optical coherence tomography (OCT) radial scans centered on the ONH were acquired every 5 min and used to quantify BMO-MRW. An exponential decay or rise to maximum function was used to determine the extent and rate of structural change. Additionally, Bruch's membrane opening (BMO) area, BMO height/displacement, and BMO-referenced anterior lamina cribrosa surface depth (BMO-ALCSD) were computed from radial scans. A circular scan was used to quantify retinal nerve fiber layer thickness (RNFLT) and circumpapillary choroid thickness. The primary results demonstrated that the BMO-MRW changed over an extended duration, while BMO displacement was rapid and remained stable with sustained IOP. The mean maximum predicted BMO-MRW thinning following 2 h of IOP elevation was significantly related to pressure (34.2 ± 13.8 μm for an IOP of 25 mmHg vs 40.5 ± 12.6 μm for 40 mmHg, p = 0.03). The half-life for BMO-MRW thinning was 21.9 ± 9.2 min for 25 mmHg and 20.9 ± 4.2 min for 40 mmHg, not significantly different between IOP levels (p = 0.76). Subsequently, after 2 h of IOP at 10 mmHg, all animals exhibited partial recovery of BMO-MRW with similar degrees of persistent residual thinning for the two IOP levels (21.5 ± 13.7 vs 21.0 ± 12.3 μm, p = 0.88). Similar to BMO-MRW, choroid thickness exhibited gradual thinning with IOP elevation and residual thinning following IOP reduction. However, there was no significant change in BMO area or BMO-ALCSD in either experimental session. The RNFLT gradually decreased over the duration of IOP elevation, with continued decreases following IOP reduction for the 40 mmHg session, resulting in total changes from baseline of −2.24 ± 0.81 and −2.45 ± 1.21 μm for 25 and 40 mmHg, respectively (p < 0.001). The sum of the results demonstrate that the ONH neural tissue is sensitive to changes in IOP, the effects of which are gradual over an extended time course and different for increased vs. decreased pressure. Understanding the duration over which IOP influences BMO-MRW has important implications for studies investigating the effects of IOP on the ONH. Additionally, individual variability in ONH response to IOP may improve our understanding of the risk and progression of disease. • Changes in intraocular pressure result in rapid changes in the neuroretinal rim. • The neuroretinal rim continues to change over a period of 2 h with sustained IOP. • Residual thinning of the neuroretinal rim persists after 2 h of IOP reduction. • There is individual variability in the rate and extent of rim tissue thinning. [ABSTRACT FROM AUTHOR]