Neural Rim Area Research Articles

Comparison of Retinal Structure Using Optical Coherence Tomography Angiography between Persons with and without HIV Infection

ABSTRACT HIV retinal microangiopathy is an important predictor for increased risk of mortality. Optical coherence tomography angiography (OCTA) can investigate microvascular changes resulting from retinal diseases. Study included 25 persons with HIV and 25 healthy persons. OCTA evaluated the vascularization of retinal layers, choriocapillary, and optic disk. HIV group had lower vessel flow density (VFD) in superficial plexus. No difference was observed in the deep plexus. VFD of the optic disk and peripapillary region showed no difference between the groups. HIV group showed a thinner retinal nerve fiber layer and smaller area of the optic disk rim. HIV infection is associated with VFD reduction in superficial retinal plexus, neural rim area reduction, and retinal nerve fiber layer thinning in individuals without microangiopathic alterations on fundus examination. Therefore, OCTA can find retinal changes before clinical evidence of retinopathy.

Signal Alteration in the Optic Nerve Head on 3D T2-weighted MRI: a Potential Neuroimaging Sign of Glaucomatous Optic Neuropathy

ABSTRACTPurpose: To investigate whether a signal alteration (SA) in the optic nerve head (ONH) on 3D T2-weighted magnetic resonance imaging (MRI) is associated with glaucomatous optic neuropathyMaterials and Methods: A total of 35 patients with bilateral open-angle glaucoma and 31 age-matched controls underwent 3D high-resolution (0.98 × 0.98 × 1 mm3) T2-weighted MRI and detailed ophthalmologic examinations including spectral-domain optical coherence tomography (OCT). Two independent reviewers blinded to subject data determined mild or prominent SA on 3D T2-weighted MRI for the incomplete or complete loss of ocular hypointense continuity in the ONH, respectively. The prevalence of SAs was compared between the two groups with the chi-square test. The OCT measurements were compared among the eyes with a mild or prominent SA and those without an SA using the Kruskal–Wallis test.Results: Of the 35 eyes with glaucoma, 26 eyes (74.3%) exhibited an SA in the ONH, whereas it was observed in 5 (16.1%) of the 31 controls (P < 0.001). The eyes with a prominent SA had a significantly different average retinal nerve fiber layer thickness (P = 0.002) and the ONH parameters except for the disk area (all P < 0.001) than those without an SA. The eyes with a mild SA had a significantly narrower neural rim area, larger cup volume, and larger average and vertical cup-to-disk ratios compared with those without an SA (P = 0.011, 0.003, 0.004, and 0.004, respectively)Conclusions: The SA in the ONH on 3D T2-weighted MRI was significantly more frequent in eyes with open-angle glaucoma than in the controls.

Characteristics of optic disc parameters and its association in normal Chinese population: the Handan Eye Study

Background Assessment of the optic disc and retinal nerve fiber layer (RNFL) is essential for the diagnosis and monitoring of glaucoma. Knowledge of normal optic disc topography provides a benchmark for evaluating glaucomatous pathologic changes, especially in its early stages. The purpose of this study was to evaluate the characteristics and correlation factors of the optic disc parameters using the Heidelberg Retina Tomograph II (HRT II) in a large sample of normal eyes of adult Chinese subjects. Methods Disc data were obtained from 6 830 subjects aged &gt;30 years from the Handan Eye Study. All participants underwent comprehensive eye examinations and physical examinations. The associations of gender, age, body mass index, blood pressure, waist-to-hip ratio; refractive error, intraocular pressure, axial length, and disc area were assessed using simple and multiple regression analysis. The correlation between HRT II parameters was evaluated. Results Of the 7 557 eligible subjects, 6 830 took part in the study (90.4% response rate) and 2 633 normal eyes with good-quality HRT II images were selected. The mean disc area was 2.28 mm2 (standard deviation (SD) 0.43) and mean neural rim area was 1.80 mm2 (SD 0.29). In multiple regression analysis, optic disc area significantly correlated with age, gender, and axial length (P &lt;0.001). All optic disc parameters showed a significant correlation with disc area (0.054 &lt;r &lt;0.736, P &lt;0.01). The association between mean RNFL thickness and rim area is statistically significant but not strong (regression linear equation: rim area = 1.42 × mean RNFL thickness + 1.32 mm2, P &lt;0.001; R 2=0.070). The global RNFL cross-sectional area was significantly associated with global rim area (regression linear equation: rim area = 1.14× RNFL cross-sectional area + 0.44 mm2, P &lt;0.001; R 2 =0.271). Conclusions The optic disc area in rural Chinese population is larger than reported in white and Japanese populations, similar to that of Indian population and urban Chinese population. Most optic disc measurements were moderately or weakly affected by disc area. In addition to the RNFL, there may be other factors affecting the rim area. The relationship between optic disc and axial length may suggest a link between larger disc area, thinning of the lamina cribrosa, and increased glaucoma susceptibility in myopic eyes.

Visual advantage in deaf adults linked to retinal changes.

The altered sensory experience of profound early onset deafness provokes sometimes large scale neural reorganisations. In particular, auditory-visual cross-modal plasticity occurs, wherein redundant auditory cortex becomes recruited to vision. However, the effect of human deafness on neural structures involved in visual processing prior to the visual cortex has never been investigated, either in humans or animals. We investigated neural changes at the retina and optic nerve head in profoundly deaf (N = 14) and hearing (N = 15) adults using Optical Coherence Tomography (OCT), an in-vivo light interference method of quantifying retinal micro-structure. We compared retinal changes with behavioural results from the same deaf and hearing adults, measuring sensitivity in the peripheral visual field using Goldmann perimetry. Deaf adults had significantly larger neural rim areas, within the optic nerve head in comparison to hearing controls suggesting greater retinal ganglion cell number. Deaf adults also demonstrated significantly larger visual field areas (indicating greater peripheral sensitivity) than controls. Furthermore, neural rim area was significantly correlated with visual field area in both deaf and hearing adults. Deaf adults also showed a significantly different pattern of retinal nerve fibre layer (RNFL) distribution compared to controls. Significant correlations between the depth of the RNFL at the inferior-nasal peripapillary retina and the corresponding far temporal and superior temporal visual field areas (sensitivity) were found. Our results show that cross-modal plasticity after early onset deafness may not be limited to the sensory cortices, noting specific retinal adaptations in early onset deaf adults which are significantly correlated with peripheral vision sensitivity.

Acute visual loss after spinal surgery

To report visual loss after prone spinal surgery. Computed tomography scan, fundus photography, optical coherence tomography (OCT). A 56-year-old man demonstrated loss of vision in the left eye after cervical spinal surgery. Clinical examination revealed loss of vision to finger counting, severe visual field defect and blurred neural rim area around the optic disc in the left eye. Six weeks later, visual acuity in the left eye was 6/9 and there was inferior visual field defect. Six months after the surgery, significant reduction of retinal nerve fibre layer thickness around the optic nerve head was measured with OCT, consistent with the visual field defect. Ischemic optic neuropathy is the most common cause of visual loss after spine surgery and special emphasis should be given to protect the eye against possible pressure during the surgery.

Visual fields and optic disc morphology in very low birthweight adolescents examined with magnetic resonance imaging of the brain

We aimed to evaluate visual fields (VFs) and optic disc morphology in very low birthweight (VLBW) adolescents compared with age- and gender-matched controls, and to relate the findings to magnetic resonance imaging (MRI) results. Fifty-nine VLBW adolescents and 55 age- and gender-matched controls with normal birthweight were examined. Visual fields were tested using computerized rarebit perimetry (RB). Optic nerve and retinal vessel morphology were evaluated by digital image analysis of fundus photographs. Brain MRI was conducted in the VLBW subjects. Ten of the 57 VLBW subjects (p = 0.022) had subnormal VF results defined as a mean hit rate below the fifth percentile of the controls (i.e. < 89%). All of these also had significantly lower mean hit rates (p = 0.039) in the inferior hemifield. Sixteen of 57 (28%) VLBW subjects had white matter damage of immaturity (WMDI) on MRI. Six of 15 subjects with WMDI (who underwent VF testing) also had subnormal RB results, compared with four of 39 with normal MRI findings (p = 0.02). The mean neural retinal rim area was 9% smaller (p = 0.018) in the VLBW group than in the control group. The VLBW adolescents had a significantly higher index for tortuosity of arterioles than the controls (p < 0.001). In the present study, 18% of all VLBW adolescents and 40% of those with WMDI had subnormal RB VF findings. The VLBW group had increased arterial tortuosity and a somewhat smaller (9%) mean neural retinal rim area than the control group. Thus sequels to VLBW appear to persist in adolescence.

Visual and cognitive function in adolescents born with very low birth weight ‐ a 15‐ year follow‐up

Abstract Purpose To describe visual functions in adolescents with VLBW in comparison with a matched control group and to investigate associations with white matter damage of immaturity (WMDI), optic disc measurements and cognitive functions in the VLBW group. Methods A total of 86 VLBW children survived the neonatal period during a 15 months period in the southeast region of Sweden. Fifty‐nine of those, and 55 term control infants, participated in the 15‐year follow‐up study. Structural assessments included brain MRI, digital analysis of fundus photographs and cycloplegic refraction. Functional evaluations comprised best corrected visual acuity, stereo acuity, visual fields, ocular alignment, cognitive visual problems and intellectual level. Results VLBW was significantly associated with smaller mean neural retinal rim area (in normal sized optic discs), subnormal visual acuity, subnormal stereo acuity and subnormal visual fields and increased frequency of astigmatism and ocular misalignment. Cognitive visual problems were more common and intelligence quotients were significantly lower in the VLBW group. WMDI occurred in 28% of the VLBW subjects. WMDI was significantly associated with visual field subnormality, myopia, ocular misalignment and cognitive visual problems. Subnormal results of performance subtests were associated with decreased visual and stereo acuity, ocular misalignment and cognitive visual problems. Conclusion This study confirms previous observations that adolescents with VLBW are at a disadvantage regarding visual and cognitive outcome compared with adolescents with normal birth weight. Adolescents with WMDI had more pronounced visual and cognitive dysfunction.

Distribution of Optic Disc Parameters Measured by OCT: Findings from a Population-Based Study of 6-Year-Old Australian Children

To study the distribution of optic disc, cup, and neural rim size by ocular and demographic variables in a population-based sample of 6-year-old children. The Sydney Childhood Eye Study examined 1765 of 2238 eligible 6-year-old children (78.9%) from 34 randomly selected Sydney schools during 2003 to 2004. Comprehensive standardized eye examination included cycloplegic autorefraction, optical biometry and "fast optic disc" scans performed using optical coherence tomography. Scans of adequate quality were available for 1309 children (75% of participants), with 70% aged 6 years; 50.9% were boys. Mean (+/- SD) horizontal and vertical disc diameter and disc area was 1.53 +/- 0.21 mm, 1.79 +/- 0.28 mm, and 2.20 +/- 0.39 mm(2), respectively. Corresponding cup dimensions were 0.70 +/- 0.28 mm, 0.73 +/- 0.27 mm, and 0.48 +/- 0.32 mm(2). A definable optic cup was absent in 7.4%, 87% of whom were European white. Cup-to-disc diameter ratios were 0.46 +/- 0.16 horizontally and 0.42 +/- 0.15 vertically, whereas cup-to-disc area ratio was 0.22 +/- 0.13. Mean +/- SD neural rim area was 1.76 +/- 0.44 mm(2) and increased with disc size (Pearson correlation = 0.68, P < 0.0001). Horizontal and vertical average nerve widths were 0.36 +/- 0.05 and 0.28 +/- 0.05 mm, respectively. In analyses adjusting for potential confounders, disc area increased significantly with axial length (P(trend) < 0.0001) and refraction (P(trend) = 0.02). Rim area increased only with axial length (P(trend) = 0.01). There were no gender differences, except for average nerve width, marginally greater in boys. Most disc and cup dimensions were significantly larger in East-Asian than European white and Middle Eastern children. Disc, cup, and neural rim parameters were generally normally distributed in this young population. Axial length appeared to be a stronger determinant of disc and rim size than refraction. Some ethnic but not gender differences were demonstrated for most parameters.

Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO), Fort Lauderdale, Florida, May 5-10, 2002.

Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO), Fort Lauderdale, Florida, May 5-10, 2002.

How Big Is Small?

D rs Slavin and Margulis’ reference to “optic discs that are developmentally small” was unsupported by any quantitative measurements or definitions. In one of the largest quantitative studies, the mean disc area was found to be 2.68 mm (range, 0.865.86 mm). Scientific and clinical reports, to have any value, must be precise. Merely stating that a disc is small provides no basis for corroboration or verification. The relative cup-disc ratio, by itself, is also misleading. “One must know the size of the optic disc to evaluate properly the cup-to-disc ratio or neural rim area.” Likewise, no explanation was offered for how Drs Slavin and Margulis determined that the origin of the presumably small discs was developmental. Could it have been the result of a prenatal process? Moreover, the authors apparently did not even acquire the requisite data— axial length, refractive error, keratometric measurements, or retinal images—that might have been used to accurately calculate disc size. Disregard of quantitative considerations is not compatible with clinical activities or scientific publications in the 21st century.

Comparing ophthalmoscopy, slide viewing, and semiautomated systems in optic disc morphometry

PurposeTo compare disc measurements obtained by indirect ophthalmoscopy, the Heidelberg Retina Tomograph (HRT), stereoscopic slide viewing (SSV) of color transparencies, and the Topcon ImageNet System (ImageNet). DesignPopulation-based cross-sectional study. MethodsFrom the Rotterdam Study, 324 subjects (567 eyes) were nonselectively included. All underwent a full ophthalmologic examination in mydriasis. Vertical cup/disc ratios (VCDRs) were compared between all four methods and disc area (mm2), neural rim area (mm2), cup area (mm2), and cup volume (mm3) between HRT and ImageNet. ResultsMean VCDR for ophthalmoscopy was 0.25 (standard error [SE], 0.007), for HRT 0.42 (SE, 0.008), for SSV 0.39 (SE, 0.010), and for ImageNet 0.50 (SE, 0.006). The correlation for VCDR between ophthalmoscopy, the two devices, and SSV was 0.42, respectively 0.57; between ImageNet and HRT 0.75. The 97.5th percentiles of the VCDR for ophthalmoscopy, HRT, SSV, and ImageNet were 0.80, 0.73, 0.80, and 0.73, respectively; the 99.5th percentiles thus were 0.90, 0.79, 0.86, and 0.79. The mean disc area, rim area, cup area, and cup volume were 2.08, 1.63, 0.45 mm2 and 0.09 mm3 for HRT, and 2.39, 1.77, 0.61 mm2 and 0.16 mm3 for ImageNet, respectively. The corresponding correlations for these four parameters were 0.67, 0.42, 0.81, and 0.82. ConclusionsDifferent techniques lead to considerable differences in disc morphometric values. ImageNet produced higher mean values compared with HRT and ophthalmoscopy. Ophthalmoscopy showed the lowest correlations and SSV the highest ones with the two semiautomated devices. Between ImageNet and HRT the correlation for all parameters was high except for the neural rim area.

Determinants of optic disc characteristics in a general population: The Rotterdam study

Objective To determine whether age, gender, height, and refractive error are associated with optic disc morphology in a general elderly population. Design Population-based, cross-sectional study. Participants A total of 5114 subjects 55 years of age or older participated in this study, representing 76% of a population-based sample of 6777 ophthalmologically examined white patients from a geographically well-defined suburb in Rotterdam, The Netherlands. Main outcome measures Disc area, neural rim area, cup area, vertical and horizontal cup-to-disc ratios, and parapapillary atrophy. Methods Disc characteristics were measured on stereoscopic simultaneous optic disc transparencies using an image analyzer. The presence and location of parapapillary atrophy, differentiated into zones alpha and beta, were assessed from disc transparencies of both eyes in a random sample of 894 persons. Subjects with open-angle glaucoma were excluded. Results The mean disc area was 2.42 mm 2 (standard deviation [SD], 0.47), mean neural rim area was 1.85 mm 2 (SD, 0.39), mean cup area was 0.57 mm 2 (SD, 0.34), mean vertical cup-to-disc ratio was 0.49 (SD, 0.14), and mean horizontal cup-to-disc ratio was 0.40 (SD, 0.14). Age was not a determinant of any disc characteristic. Disc and rim areas were 3.2% ( P < 0.0005; 95% confidence interval [CI], 2.7%–3.7%) and 4.3% ( P < 0.0005; 95% CI, 3.5%–4.6%) larger in men than in women. For each diopter increase toward myopia, the disc area increased by 0.033 mm 2 ( P < 0.0005; 95% CI, 0.027–0.038) and neural rim area by 0.029 mm 2 ( P < 0.0005; 95% CI, 0.025–0.034). The disc area increased by 0.02 mm 2 ( P = 0.02; 95% CI, 0.005,0.05) for each 10-cm increase in height. The prevalence of zone alpha slightly decreased by 0.4% per 10 years of age ( P = 0.035; 95% CI, 0.03%–0.8%), whereas the prevalence of zone beta increased by 1.3% ( P = 0.0003; 95% CI, 0.57%–1.9%) for each diopter increase toward myopia. Conclusions In a general population, statistically normal discs may vary twofold in disc area and threefold in rim area. Age is not associated with any disc characteristic, whereas disc area and neural rim area are slightly larger in men than in women. Refractive error is weakly related to disc area and neural rim area. Height is weakly related to disc area in persons of medium height. The prevalence of zone beta is higher in myopic eyes.

Comparative Optic Disc Analysis in Normal Pressure Glaucoma, Primary Open-angle Glaucoma, and Ocular Hypertension

The authors wished to determine whether characteristics of optic disc and parapapillary atrophy differ between eyes with ocular hypertension, primary open-angle glaucoma (POAG) and those with normal-pressure glaucoma, including a subset of patients with normal-pressure glaucoma with evidence of serum abnormalities of humoral autoimmunity. Three hundred ninety-two eyes of 196 patients with ocular hypertension, 394 eyes of 197 patients with POAG, and 135 eyes of 68 patients with normal-pressure glaucoma were analyzed. Nerve fiber layer hemorrhage in the optic disc region, retinal arteriolar narrowing, and morphometric parameters of optic disc and parapapillary atrophy were investigated in these groups. Parapapillary atrophy was differentiated in two different zones (alpha and beta). Nerve fiber layer hemorrhage and arteriolar narrowing were found more frequently in patients with normal-pressure glaucoma than in patients with POAG (P = 0.014, P = 0.004) and ocular hypertension (P < 0.0001, P < 0.0001). Zone beta was detected more often in patients with normal-pressure glaucoma than in those with ocular hypertension (P < 0.001) and POAG (P = 0.013). Although patients with normal-pressure glaucoma had more advanced neural rim loss and larger parapapillary atrophy, there were similar correlations between neural rim area and the area and extension of parapapillary atrophy in patients with normal-pressure glaucoma and POAG. Parapapillary atrophy parameters also were similar in different stages of neural rim damage in patients with normal-pressure glaucoma and POAG (P > 0.05). Optic disc characteristics were not different (P > 0.05) between the subgroups of patients with normal-pressure glaucoma. The authors' findings support the idea that besides the enlargement of the area and extension of parapapillary atrophy that accompanies neural damage in glaucoma, the severity of the parapapillary atrophy also increases as assessed by the increase in zone beta in more damaged eyes. Furthermore, the final clinical appearance of optic nerve damage is similar among patients with POAG, normal-pressure glaucoma, and the subgroups of normal-pressure glaucoma, regardless of their possibly different mechanisms of neuropathy.

Neural Rim Area Declines With Increased Intraocular Pressure in Urban Americans

I read with interest the article by Varma et al 1 in the August 1995 issue of theArchives. They made an important observation of intraocular pressure (IOP)—related decline in the neural rim area among urban Americans who did not have known optic nerve damage. They believe that the IOP-related decline in neural rim area probably represents loss of neural tissue in the optic nerve, rather than IOP-related posterior deformation of the optic disc tissue or loss of astroglial tissue in the optic nerve. I have no problem with the authors' contention regarding lack of involvement of the astroglial tissue loss. However, I do not believe that the apparent decline in neural rim area is entirely due to loss of neural tissue in the optic nerve. Our experience regarding IOP-dependent dynamic changes in optic disc cupping in patients with primary, open-angle glaucoma suggests otherwise. 2 Therefore, the IOP-related decline in

Neural Rim Area Declines With Increased Intraocular Pressure in Urban Americans-Reply

Neural Rim Area Declines With Increased Intraocular Pressure in Urban Americans-Reply

Neural rim area declines with increased intraocular pressure in urban Americans.

To determine intraocular pressure (IOP)-related differences in the neural rim area among urban Americans without known optic nerve disease. Population-based prevalence study conducted in 16 cluster areas in East Baltimore, Md. A population-based sample of 1521 black and 1851 white individuals aged 40 years and older without evidence of optic nerve disease. Intraocular pressure-related differences in neural rim area, neural rim area-to-disc area ratio, and cup-to-disc ratio. We analyzed optic disc photographs using the Imagenet system (Topcon Instrument Corp of America, Paramus, NJ). After adjusting for age and disc area, white Americans had a 6% decrease in neural rim area for every 10-mm Hg increase in IOP (P = .0001). In black Americans, there was a quadratic relationship between neural rim area and IOP, with little decline with IOP up to approximately 17 mm Hg, after which neural rim area declined significantly with higher IOP (P = .001). Similarly, the neural rim area-to-disc area ratio decreased and the vertical cup-to-disc ratio increased with increasing IOP in both black and white Americans. The higher the level of IOP, the smaller was the amount of neural rim tissue in the optic disc for both black and white Americans. However, the relationship between IOP and neural rim area was different in whites and blacks.

Race-, Age-, Gender-, and Refractive Error—Related Differences in the Normal Optic Disc

To determine race-, age-, gender-, and refractive error-related differences in the size and topography of the optic disc in healthy Americans. Population-based study. Eastern and southeastern health districts of Baltimore, Md. A population-based sample of 4877 non-institutionalized black and white individuals aged 40 years or older without evidence of optic nerve disease. Race-, age-, gender-, and refractive error-related differences in optic disc measurements: disc area, neural rim area, cup area, cup-to-disc ratio, and neural rim area-to-disc area ratio. We analyzed simultaneous stereoscopic optic disc photographs from 3387 (1534 black and 1853 white) of the 4877 healthy individuals using an image analyzer (Topcon Image Analyzer, Topcon Instrument Corporation, Paramus, NJ). A total of 1490 individuals were excluded owing to the absence of good-quality images from either eye. The image analyzer defined the cup margin 150 microns below the surface of the disc margin. On average, blacks had significantly larger disc areas (blacks, 2.94 mm2; whites, 2.63 mm2), larger cup areas (blacks, 1.04 mm2; whites, 0.71 mm2), larger cup-to-disc ratios (blacks, 0.56; whites, 0.49), similar neural rim areas (blacks, 1.90 mm2; whites, 1.92 mm2), and smaller neural rim area-to-disc area ratios (blacks, 0.66; whites, 0.74) compared with whites. There were no age-related differences in any of the disc measurements. Male subjects had 2% to 3% larger optic discs compared with female subjects. No association between refractive error and any of the optic disc measurements studied was detected. Racial differences in the normal optic disc are present among urban Americans, and these differences must be considered in evaluation of the optic disc for glaucoma and other optic neuropathies. Among the individuals in our study, all of whom were 40 years of age or older, no progressive age-related decline in neural rim area was detectable. Neither gender nor refractive error were associated with any significant differences in the size and topography of the normal optic disc.

Larger Optic Nerve Heads Have More Nerve Fibers in Normal Monkey Eyes

The cup-to-disc ratio and the neural rim area are used to detect glaucoma damage to the optic nerve. Both parameters are dependent on the size of the optic disc and on the number of optic nerve fibers. We compared the size of the disc in fundus photographs with the number of nerve fibers in 25 normal monkey eyes. The number of fibers increased linearly with an increasing disc area. One must know the size of the optic disc to evaluate properly the cup-to-disc ratio or neural rim area.

Reproducibility of Topographic Measurements with the Optic Nerve Head Analyzer

We evaluated the reproducibility of optic nerve head contour mapping by the Optic Nerve Head Analyzer with ten recordings and analyses of one eye each in ten normal volunteers and ten analyses of a single recording in three of the eyes. Reproducibility was good for cup-to-disk ratio and neural rim area. Reproducibility was poor for cup volume, which was inversely related to cup size. Instrument and operator error were low for cup-to-disk ratio and neural rim area, but high for cup volume. Subjective comparisons of contour lines from five recordings of six eyes implied good reproducibility of this measurement.