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Purpose To determine what percentage of normal eyes follow the ISNT rule, and whether ISNT rule variants may be more generalizable to the normal population. Design Cross-sectional study. Methods Setting: Institutional setting. Study Population: Total of 110 normal subjects. Observation Procedures: Neuroretinal rim assessments from disc photographs and retinal nerve fiber layer (RNFL) thickness measurements from spectral-domain optical coherence tomography. Main Outcome Measures: The percentages of subjects that obeyed the ISNT rule and its variants. Results The ISNT rule is only valid for 37.0% of disc photograph rim assessments and 43.8% of RNFL measurements. Deviation of the nasal sector from the expected ISNT pattern was a major cause for the ISNT rule not being obeyed for both rim and RNFL assessments. Specifically, 10.9% of subjects had wider nasal rims than the inferior rims, 29.4% had wider nasal rims than the superior rims, 14.7% had narrower nasal rims than the temporal rims, and 42.9% had thinner nasal RNFLs compared to the temporal quadrant. Exclusion of the nasal quadrant from the ISNT rule significantly increased the validity of ISNT variant rules, with 70.9% and 76.4% of disc photographs following the IST rule and the IS rule, respectively. Similarly, for RNFL thickness, 70.9% and 71.8% of patients followed the IST and IS rule, respectively. Conclusions The ISNT rule is only valid for about a third of disc photographs and less than half of RNFL measurements in normal patients. ISNT rule variants, such as the IST and IS rule, may be considered, as they are valid in more than 70% of patients.

Objective To assess the impact of trabeculectomy for glaucoma on morphometric neuroretinal parameters of the optic nerve head (ONH) using spectral-domain optical coherence tomography (SD-OCT). Design Retrospective, interventional case series. Methods Participants : Eighty-eight eyes of 88 patients who underwent trabeculectomy with mitomycin C in 2016. Intervention : All patients underwent trabeculectomy in 1 eye (study eye) and had evaluable SD-OCT examinations of the ONH to measure neuroretinal tissue before and at least at 1 of the 3-, 6-, and 12-month follow-up time points after surgery. Main Outcome Measures : Longitudinal change in Bruch membrane opening minimum rim width (BMO-MRW), Bruch membrane opening minimum rim area (BMO-MRA), peripapillary retinal nerve fiber layer (RNFL) thickness, intraocular pressure (IOP), and mean deviation in perimetry. Results In study eyes, BMO-MRW significantly increased postsurgically comparing baseline and follow-up examinations at 3 months (P = .012), at 6 months (P = .007), and at 1 year (P = .010) after trabeculectomy. The increase in BMO-MRW 6 months after surgery correlated with IOP reduction (r = 0.48; P = .001). BMO-MRA showed an equal increase (P ≤ .034). RNFL thickness remained stable between baseline and follow-up at 3, 6, and 12 months and showed a moderate loss after 18 months (P = .021) of follow-up. Conclusions Structural reversal of disc cupping after trabeculectomy markedly influences Bruch membrane opening–based parameters for up to more than 1 year. Improvement in morphometry seems to correlate with the reduction of IOP while visual field function appears not to be influenced. In longitudinal follow-up of glaucoma patients by SD-OCT, evaluation of BMO-based parameters necessitates to reflect bias caused by surgery.

Purpose To determine the spatial relationship in neuroretinal rim parameter values between eyes in ocular hypertensives, glaucoma suspects, and glaucoma patients. Design Observational-cross-sectional study. Methods A total of 334 eyes of 167 patients were included. All patients underwent confocal scanning laser ophthalmoscopy imaging in both eyes. Intereye concordance ratio of abnormal rim sectors as classified by the Moorfield regression analysis (MRA) was calculated as the ratio of matching abnormal rim areas to the total number of abnormal rim areas. The amount of agreement was calculated for each sector separately. Results Of the right (left) eyes, 39 (39) eyes were classified “borderline” (BL) by MRA, 62 (65) eyes were “within normal limits” (WNL), and 66 (63) eyes “outside normal limits” (ONL). A total of 78 patients had a normal overall MRA result in both eyes (BL = WNL). Of the 89 patients with a defect in at least one sector, mean intereye concordance was 0.28 ± 0.04 (BL = WNL). When considering BL as ONL, concordance increased to 0.43 ± 0.03. The lowest intereye agreement in rim abnormality was found in the temporal-inferior sector with 29.0% (Kappa ± SE [standard error], 0.25 ± 0.09, BL = WNL) matching. The highest agreement was found in the nasal- inferior sector with 47% (Kappa ± SE, 0.53 ± 0.1, BL = WNL) matching. Conclusions There is a moderate intereye agreement in abnormal neuroretinal rim locations in eyes of ocular hypertensives, glaucoma suspects, and glaucoma patients. Longitudinal studies are needed to elucidate the agreement over time and to better understand the morphological pattern of progression between eyes in glaucoma.

Purpose To compare rim area rates in patients with and without the visual field (VF) progression endpoint in the Canadian Glaucoma Study and determine whether intraocular pressure (IOP) reduction following the endpoint altered rim area rate. Design Prospective multicenter cohort study. Methods setting: University hospitals. patient population: Two hundred and six patients with open-angle glaucoma were examined at 4-month intervals with standard automated perimetry and confocal scanning laser tomography. intervention: After the endpoint, IOP was reduced by ≥20%. outcome measures: Univariate analysis for change in rim area rate and multivariable analysis to adjust for independent covariates (eg, age, sex, and IOP). Results Patients with an endpoint (n = 59) had a worse rim area rate prior to the endpoint compared to those without (n = 147; median [interquartile range]: −14 [−32, 11] × 10 −3 mm 2 /y and −5 [−14, 5] × 10 −3 mm 2 /y, respectively, P = .02). In univariate analysis, there was no difference in rim area rate before and after the endpoint (median difference [95% CI], 8 (−10, 24) × 10 −3 mm 2 /y), but the muItivariate analysis showed that IOP reduction >2 mm Hg after the endpoint was strongly linked to a reduction in rim area rate decline (8 × 10 −3 mm 2 /y for each additional 1 mm Hg reduction). Conclusions Patients with a VF endpoint had a median rim area rate that was nearly 3 times worse than those without an endpoint. Lower mean follow-up IOP was independently associated with a slower decline in rim area.

• Purpose: To compare laser tomographic scanning evaluation with photographic measurement of size and shape of the neuroretinal rim. • Methods: For 25 normal eyes and 32 glaucomatous eyes, the optic disks were examined with the Heidelberg Retina Tomograph (software version 1.11) for confocal laser tomographic scanning evaluation, and color stereoscopic optic disk photographs for planimetric measurements. Area and width of the neuroretinal rim were determined as percentages of the disk area and diameter, respectively. • Results: For the normal and glaucomatous eyes, the tomographic results compared with the photographic measurements disclosed significantly larger values for the relative width and relative area of the neuroretinal rim. The differences between both methods were most marked in the nasal part of the optic disk and least marked in the temporal disk region. The relative differences increased significantly (P • Conclusions: In normal and glaucomatous eyes, the Heidelberg Retina Tomograph determines the neuroretinal rim, expressed as percentage of optic disk measurements, to be significantly larger than when the rim is evaluated on optic disk photographs. Because parts of the central retinal vessel trunk are defined as neuroretinal rim in the algorithm of the Heidelberg Retina Tomograph, the differences between Heidelberg Retina Tomograph measurements and photographic determinations of the rim are largest in the nasal disk region and smallest in the temporal disk area. The neuroretinal rim shape and neuroretinal rim area differ appreciably between the two methods. These differences increase with increasing degree of glaucomatous optic nerve damage.

Purpose This study was performed to differentiate glaucomatous changes of the optic disk that may be caused by increased intraocular pressure from those that may be pressure independent. Methods For 357 patients with primary open-angle glaucoma, the optic disk was morphometrically analyzed, and the intraocular pressure was measured in 24-hour profiles. Results By performing an intraindividual bilateral comparison, the differences in the maximal intraocular pressure values of the right eye minus the left eye of the same individual were significantly correlated with the differences in neuroretinal rim area and mean perimetric defect of the right eye minus the left eye. No significant correlations were found for the parapapillary atrophy. Conclusions The results indicate that the eye with the higher pressure compared with the fellow eye with the lower pressure showed neither a significantly larger nor smaller parapapillary atrophy, which suggests that the parapapillary atrophy, compared with the neuroretinal rim area and the visual field defect, is less dependent or almost independent of an increased intraocular pressure.

We compared the change in cup/disk ratio and neuroretinal rim area-to-disk area to estimated change in the number of optic nerve fibers in 12 cynomolgus monkeys with unilateral experimental glaucoma. Changes in the cup/disk ratios and neuroretinal rim area-to-disk area were estimated from stereoscopic optic disk photographs that were obtained before and after the development of increased intraocular pressure. Change in the number of optic nerve fibers in the glaucomatous nerves was estimated by comparing them to their fellow normal nerves. A significant linear correlation was present between change in the cup/disk ratios and neuroretinal rim area-to-disk area, and estimated change in the number of optic nerve fibers (r > or = .85; P < .0002). In optic disks with initial cup/disk ratios of 0.2 to 0.3 and neuroretinal rim area-to-disk area of 0.9, an increase in the cup/disk ratio of 0.1 and a decrease of 0.1 in the neuroretinal rim area-to-disk area is associated with a 10% and 9% loss of optic nerve fibers, respectively.

To assess the neuroretinal rim shape in a population-based study.Population-based, cross-sectional cohort study.The Beijing Eye Study included 4,439 subjects with an age of 40+ years. On color optic disk photographs of a random sample of 92 subjects (92 eyes), neuroretinal rim width and area were measured in different disk sectors.The neuroretinal rim was significantly (P = .038) wider in the inferior disk region (0.52 +/- 0.11 mm) than in the superior disk region (0.49 +/- 0.10 mm), where it was significantly (P.001) wider than in the nasal disk region (0.47 +/- 0.09 mm) and was significantly (P.001) the smallest in the temporal disk region (0.40 +/- 0.12 mm). The rim was significantly wider inferiorly ("I"), followed by the superior disk region ("S"), the nasal disk region ("N"), and finally the temporal disk region ("T") [ISNT] rule defined as the rim being larger inferiorly than superiorly, being larger than nasally and being larger than temporally, was fulfilled in 48 (52%) subjects.In adult Chinese as in Caucasians, the neuroretinal rim usually follows the ISNT rule.

Purpose To review and interpret the anatomy of the optic nerve head (ONH) detected with spectral-domain optical coherence tomography (SD OCT) pertaining to the clinical examination of the optic disc and to propose that a paradigm change for clinical assessment of the ONH is necessary. Design Perspective. Methods Presently, the clinician evaluates neuroretinal rim health according to the appearance of the optic disc, the clinically visible surface of the ONH. Recent anatomic findings with SD OCT have challenged the basis and accuracy of current rim evaluation. We demonstrate why incorporation of SD OCT imaging of the ONH into the clinical examination of the disc is required. Results Disc margin-based rim evaluation lacks a solid anatomic basis and results in variably inaccurate measurements for 2 reasons. First, the clinically visible disc margin is an unreliable outer border of rim tissue because of clinically and photographically invisible extensions of Bruch's membrane. Second, rim tissue orientation is not considered in width measurements. We propose alternative anatomically and geometrically accurate SD OCT-based approaches for rim assessment that have enhanced detection of glaucoma. We also argue for new data acquisition and analysis strategies with SD OCT that account for the large interindividual variability in the angle between the fovea and ONH. Conclusions We propose a 4-point paradigm change for clinical assessment of the ONH that is anchored to the eye-specific anatomy and geometry of the ONH and fovea. Our approach is designed to enhance the accuracy and consistency of rim width, as well as of peripapillary and macular intraretinal thickness measurements.

We evaluated the frequency and location of optic disk hemorrhages by examining morphometrically color stereo optic disk photographs of 1,505 glaucomatous eyes and 595 normal eyes. Disk hemorrhages were found in 61 of the glaucomatous eyes (4.1%) and in none of the normal eyes. The frequency of the hemorrhages increased from an early stage of glaucoma to a medium-advanced stage and decreased again toward a far-advanced stage. The disk hemorrhages were not found in disk regions or eyes without detectable neuroretinal rim. In early glaucoma, they were usually located in the inferotemporal or superior disk regions. (The frequency of hemorrhages was 6.3% in normal-pressure glaucoma, 4.9% in primary open-angle glaucoma, and 3.1% in secondary open-angle glaucoma.) They were correlated with localized retinal nerve fiber layer defects, neuroretinal rim notches, and circumscribed perimetric loss. These characteristics imply the pathogenetic and diagnostic importance of disk hemorrhages for the detection of glaucoma.

V ISUAL DAMAGE IN GLAUCOMA IS BELIEVED TO BE caused at least in part by the pressure within the eye initiating a cascade of events, leading to death of the ganglion cells. The level of intraocular pressure required to cause the damage varies markedly in an individual. Additionally, a hallmark of glaucoma is the localized nature of damage to the optic disk and visual field; the neuroretinal rim of the optic disk could be essentially dead in one area and yet apparently healthy in another. Several authors have advanced pathogenetic

The video-ophthalmograph (Rodenstock analyzer) records the topography of the optic disk via simultaneous stereoscopic video images which are stored and analyzed with the help of a microcomputer. We performed a prospective study of 49 eyes of 49 patients to compare the vertical cup-disk ratio, the horizontal cup-disk ratio, the neuroretinal rim area, and the optic disk area obtained with the video-ophthalmograph with those obtained with manual analysis of black-and-white stereoscopic photographs. The correlation coefficients were 0.67, for vertical cup-disk ratio (P = .0000), 0.63 for horizontal cup-disk ratio (P = .0000), 0.72 for neuroretinal rim area (P = .0000), and 0.89 for optic disk area (P = .0000).

Magnification-corrected measurements of neuroretinal rim area of the optic disk were correlated to visual field indices calculated from 49 thresholds of Octopus program JO. The indices express overall reduction and localized disturbances of retinal sensitivity. The study was composed of 123 subjects, including 23 normal subjects, 49 patients suspected of having glaucoma, and 51 patients with glaucoma. The neuroretinal rim area was highly significantly correlated with both visual field indices; the index for overall loss of retinal sensitivity had a somewhat higher correlation coefficient than the index expressing localized visual field changes. Adequate fit of visual field data on rim area was achieved by quadratic regression.

The neuroretinal rim area of the optic nerve head was measured in 33 normal individuals, 50 subjects suspected of having glaucoma, and 51 patients with glaucoma. The measurements were corrected for magnification produced by the optical system of the eye. The rim areas were statistically highly significantly different in these clinical groups. Mean neuroretinal rim area in the normal controls was 1.40 ± 0.186 mm 2 . Therefore, 95% of the normal subjects had rim areas greater than 1.09 mm 2 ; 30% of the subjects with ocular hypertension and 73% of the patients with glaucoma had rim areas less than 1.09 mm 2 .

We randomly photographed 113 eyes in 113 people without ocular disease. The area of the disk and its neuroretinal rim as well as the width of the disk and cup were measured. The measurements were corrected for magnification of each eye by measuring its refraction and axial length. A linear correlation between disk area and neuroretinal rim area was found ( r = .75) as well as a correlation between the disk area and the cup area ( r = .83). There was no correlation between age and disk area or rim area.

Using planimetric analysis of stereoscopic optic disk photographs, we studied 21 optic nerve heads of 11 subjects who shared the common feature of optic cups that were larger than the mean + 2 S.D. within the normal population. A comparison of these findings to those of 571 normal optic disks and 706 optic nerve heads in eyes with chronic primary open-angle glaucoma showed the following morphologic characteristics: (1) abnormally large optic disk area (mean +/- S.D., 4.49 +/- 0.56 mm2), (2) large cup/disk ratios with the horizontal ratio (0.78 +/- 0.03) significantly (P less than .001) larger that the vertical (0.71 +/- 0.03), (3) increased incidence of cilioretinal arteries, (4) normal neuroretinal rim area (2.06 +/- 0.35 mm2), (5) normal neuroretinal rim configuration, inferiorly (0.43 +/- 0.08 mm) broader (P less than .001, Wilcoxon test) than superiorly (0.33 +/- 0.06 mm), smallest (P less than .0001) temporally (0.20 +/- 0.04 mm), (6) normal form of zone alpha (irregular hypopigmentation and hyperpigmentation) of the parapapillary chorioretinal atrophy with its widest extension in the temporal horizontal area, (7) no zone beta (visible large choroidal vessels and sclera), (8) normal caliber of the parapapillary retinal vessels, and (9) normal parapillary retinal nerve fiber layer. These characteristics are helpful in the differentiation of primary and secondary large cups.