Position of the fovea centralis with respect to the optic nerve head.

Examination of the ocular fundus via indirect ophthalmoscopy gives the clinician an impression of foveal position relative to the nerve head. In some patients, the fovea appears to be in an unusual position (i.e., ectopic): it may appear to be higher or lower than expected, or closer to or farther from the nerve head. There is little published quantitative information on this subject. The purpose of this study was to examine foveal position in a group of normal adult eyes, so that clinicians and other researchers will be able to determine on a more objective basis whether or not a given patient shows foveal ectopia. Using ocular fundus photographs for 446 normal adult eyes, we found the foveal center to be, on average, 6.11 degrees +/- 3.32 degrees below a horizontal line bisecting the nerve head. For a smaller sample of 66 eyes, we found the average distance between the nerve head and foveal centers to be 4.93 +/- 0.33 mm (right eye) and 4.88 +/- 0.36 mm (left eye). Correlations of these data for right and left eyes are also examined. Nerve head data for the group of 66 right eyes were also analyzed to yield dimensions of a best-fitting ellipse: the mean minor axis was 1.75 +/- 0.2 mm; the mean major axis 1.95 +/- 0.2 mm. Ectopia (heterotopia) of the fovea has been found in association with chorioretinitis, fibrous traction bands, and/or colobomas of the choroid and optic nerve (including anomalous insertion of the optic nerve), microcephalus, and microphthalmia. A number of separate cases with anomalous nerve heads and/or foveal positions are discussed in this paper.(ABSTRACT TRUNCATED AT 250 WORDS)     

Correlation of the optic disc size to glaucoma susceptibility

Previous studies have suggested that a larger optic disc size in blacks as compared with whites is related to the increased glaucoma susceptibility in blacks. In an intraindividual bilateral comparison of 245 white patients with open-angle glaucoma, the authors evaluated whether the glaucomatous optic nerve damage was greater or less in the eye with the larger optic nerve head. Highly myopic eyes were excluded. The difference in optic disc area of one eye as compared with the contralateral eye was not significantly correlated to the differences in visibility of retinal nerve fiber bundles and mean visual field defect between the two eyes. Mean perimetric loss and the retinal nerve fiber layer index were not significantly higher in the eye with the larger or smaller optic nerve head. This indicates that in whites, high myopes excluded, the susceptibility to glaucomatous optic nerve fiber loss may be independent of the optic disc size.     

Fixation characteristics of patients with macular degeneration recorded with the mp-1 microperimeter

PURPOSE: The authors examined the fixation stability patterns of people with age-related macular degeneration (AMD) using the MP-1 microperimeter and describe a method to bypass some calibration artifacts that can influence the fixation results. METHOD: The preferred retinal locus (PRL) and fixation patterns of 37 eyes with AMD and the fovea's location relative to the middle of the optic disc of 10 experienced controls were measured. For the patients, fixation characteristics such as the former fovea's location, PRL distance, and fixation stability were analyzed. RESULTS: For the controls, the mean foveal distance temporal to the middle of the optic disc was 15.5 deg +/- 0.86 deg horizontally and -1.33 deg +/- 0.71 deg vertically. Thirty-one out of 37 PRLs occurred in the upper and right quadrants of the retina. There were significant positive correlations between fixation stability and PRL distance from the former fovea. Time since diagnosis and acuity also showed positive correlations with fixation stability and PRL distance from the fovea. CONCLUSIONS: The authors recommend that fixation stability recorded with the MP-1 be analyzed based on the raw data. Most of the fixation parameters obtained agree with those reported in the literature, if proper calibration is used.     

Extraocular muscle insertions relative to the fovea and optic nerve: humans and rhesus macaque

PURPOSE: To identify extraocular anatomic relationships of muscle insertions relative to the fovea and the optic nerve. METHODS: Thirty-eight human eye bank eyes and 10 rhesus macaque (Macaca mulatta) eyes were measured. Ten human volunteers were used to determine the horizontal rectus muscle-to-globe apposition in primary, left, and right gaze. RESULTS: External globe measurements (human/rhesus; mm +/- SD) from the temporal border of the optic nerve (ON) to the center of the fovea (F) were 3.7 +/- 0.6 and 2.6 +/- 0.2; F to the posterior border of the inferior oblique (IO) insertion, 2.5 +/- 0.8 and 0.5 +/- 0.4; ON to the posterior border of the IO, 5.6 +/- 0.9 and 2.8 +/- 0.3; horizontal axial plane (H) of the eye, defined by the long posterior ciliary artery, to the IO, 2.0 +/- 0.8 and 0.5 +/- 0.4; and H to F, 1.0 +/- 0.6 and 0.4 +/- 0.3, respectively. The IO insertion formed an arc, inferior to H, with an anterior-to-posterior cord insertion width of 9.2 +/- 0.7 and 7.7 +/- 0.3. The IO angle of insertion (theta) was 30 degrees in 84% (32/38) and 0 degrees in 16% (6/38) of human eyes and 25 to 30 degrees in all rhesus. In 20 human volunteers, from the ON to the apex of lateral rectus globe apposition was 13.9 +/- 1.1 in primary, 17.2 +/- 1.9 in lateral, and 9.3 +/- 1.7 in medial gaze. CONCLUSIONS: The fovea is located mostly superior and slightly posterior to the posterior border of the IO insertion. Topographic relationships of the extraocular muscles relative to the fovea are essential for the design of extraocular drug delivery systems.     

Comparison of optical coherence tomography and fundus photography for measuring the optic disc size

PURPOSE: To assess the agreement and repeatability of optic nerve head (ONH) size measurements by optical coherence tomography (OCT) as compared to conventional planimetry of fundus photographs in normal eyes. METHODS: For comparison with planimetry the absolute size of the ONH of 25 eyes from 25 normal subjects were measured by both OCT and digital fundus photography (Zeiss FF camera 450). Repeatability of automated Stratus OCT measurements were investigated by repeatedly measuring the optic disc in five normal subjects. RESULTS: Mean disc size was 1763 +/- 186 vertically and 1632 +/- 160 microm horizontally on planimetry. On OCT, values of 1772 +/- 317 microm vertically (p = 0.82) and a significantly smaller horizontal diameter of 1492 +/- 302 microm (p = 0.04) were obtained. The 95% limits of agreement were (-546 microm; +527 microm) for vertical and (-502 microm; +782 microm) for horizontal planimetric compared to OCT measurements. In some cases large discrepancies existed. Repeatability of automatic measurements of the optic disc by OCT was moderately good with intra-class correlation coefficients (ICC) of 0.78 horizontally and 0.83 vertically. The coefficient of repeatability indicating instrument precision was 80 microm for horizontal and 168 microm for vertical measurements. CONCLUSIONS: OCT can be used to determine optic disc margins in moderate agreement with planimetry in normal subjects. However, in some cases significant disagreement with photographic assessment may occur making manual inspection advisable. Automatic disc detection by OCT is moderately repeatable.     

Optic disc size and optic nerve damage in normal pressure glaucoma.

BACKGROUND--Recent reports indicate that eyes with normal pressure glaucoma have larger optic discs than eyes with primary open angle glaucoma or normal eyes. This study was performed to find whether, in normal pressure glaucoma, a large disc is associated with more optic nerve damage than a small disc. METHODS--Colour optic disc photographs of 74 patients with normal pressure glaucoma were assessed morphometrically. RESULTS--Taking the study group as a whole, the optic disc size decreased significantly (p = 0.04) with increasing visual field defect. In an intraindividual bilateral comparison, the side differences in the disc area of the right minus the left eye of the same individual were not significantly correlated with the side differences in the mean visual field defect. CONCLUSIONS--The results indicate that the eye with the larger optic disc, when compared with the contralateral eye with the smaller optic nerve head, showed neither a significantly more marked nor less pronounced glaucomatous optic nerve damage. It suggests that for a given patient the degree of glaucomatous optic nerve atrophy was not markedly associated with the optic disc size. The finding that patients with large visual field defects had smaller discs than patients with moderate perimetric loss may indicate that the results of previous cross sectional studies reporting on an unusually large disc size in normal pressure glaucoma may be due partially to selection.     

Reproducibility of the measurements of the optic nerve head topographic variables with a confocal scanning laser ophthalmoscope

PURPOSE: To determine the optic nerve head topographic parameters with the least variability in repeat measurements. METHODS: We randomly selected and evaluated 1 eye each of 20 healthy subjects, a total of 20 eyes. We used the confocal scanning laser ophthalmoscope (CSLO) for optic nerve head analysis. The disc area and a total of 13 parameters were determined by Top SS. Each subject was examined five times, each time on a different day, during a 2-month period. We obtained a series of five 10 x 10 degrees images for each eye per visit. Three of the five images were randomly selected to create a mean image. Coefficients of variation of each of the 13 variables studied were calculated separately by using those five different optic nerve head topographic measurements. RESULTS: The subjects were 11 women and 9 men. The mean age of the subjects was 30.5 +/- 6.9. The mean optic disc areas were 2.26 +/- 0.39 mm(2) and 1.96 +/- 0.37 mm(2) for the men and the women, respectively (P >.05). The mean coefficient of variation for measurement of the variables was found to range between 1.2% and 9.8%. The variables, cup shape, volume above, average depth, and volume below, were found to yield the best reproducible measurements. CONCLUSION: The CSLO with its highly reproducible measurements (<10% error) offers a highly objective, safe, and effective method for clinical use in measurements of the topography of the optic nerve head. The subtle differences in the variables, cup shape, volume above, average depth, and volume below, may be of vital importance in the follow-up of those diseases requiring longitudinal monitoring of the optic nerve head, namely ocular hypertension and glaucoma.     

Papilläre Hämodynamik bei Patienten mit Normaldruckglaukom und Papillenrandblutungen

Background. Optic disc hemorrhages in patients with normal-pressure glaucoma (NPG) are usually regarded as a sign of vascular dysfunction and as an indicator for glaucoma damage progression. Methods. Optic nerve head blood flow was measured in 21 patients suffering from NPG with acute optic disc hemorrhages by scanning laser Doppler flowmetry at various locations of the optic disc. Intraocular pressure and mean deviation of the visual field were also monitored. Two groups served as control: 21 patients with NPG matched for age, sex, and stage of the disease and in addition the contralateral eye without any hemorrhages. Results. Optic nerve head blood flow as a mean of several locations was significantly lower in eyes with optic disc hemorrhages than in controls and differed significantly from the contralateral eye. Conclusion. Optic nerve blood flow was lower in NPG eyes with optic disc hemorrhages than in the contralateral eye and in controls.     

Wie tief muss die radiäre Optikusneurotomie zur Therapie des retinalen Zentralvenenverschlusses sein?

PURPOSE: Most of the studies on radial optic neurotomy (RON) have not defined the depth of the incision. Complications following a deeper incision have been described. This histological study was performed to evaluate the required depth for RON. METHODS: Serial sections of the area of the optic nerve head were performed in 19 eye bank eyes. The distance between the inner surface of the optic disc and the outer limit of the cribriform plate was measured. Ten additional eye bank eyes underwent 2 mm deep experimental RON using the Spaide CRVO Knife (DORC, Netherlands). The cutting depth was assessed histologically by serial cuts. RESULTS: The distance between the inner surface of the disc and the outer limit of the cribriform plate measured 1.35+/-0.3 mm (shrinkage-revised value: 1.45 mm). The experimental RON showed cutting depths of 1.53+/-0.3 mm (shrinkage-revised value: 1.65 mm). CONCLUSION: Based on normal eyes, a cutting depth of 1.45 mm is sufficient to cut through the cribriform plate. This might change during central retinal vein occlusion because possible papillary edema due to central retinal vein occlusion has to be considered. Even under controlled experimental conditions RON leads to great variation in incision depths. The development of a knife with a fixed penetration depth would be helpful.     

Ocular manifestations in fetal alcohol syndrome

PURPOSE: To report the prevalence of ocular abnormalities in a group of Portuguese children with a complete fetal alcohol syndrome (FAS). METHODS: Complete ophthalmologic examination in a sample of consecutive children with FAS. Ocular fundus photography was carried out on the cooperative FAS children and on 25 reference children. Ocular fundus anomalies were recorded by the observation of ocular fundus photography. The ratio between the distance of the center of the disc to the fovea and optic disc diameter (DM/DD) was determined. Small optic disc was defined as a DM/DD ratio above mean control group +1 SD. RESULTS: The authors studied 32 children with FAS (mean age: 9 +/- 5 years; 72% boys). The mean corrected visual acuity (VA) was 0.8 +/- 0.2. Refraction ranged from -23.00 to +6.50 spherical equivalent. Ocular findings included short horizontal palpebral fissure (81% of children), strabismus (28% of children), epicanthus (27% of eyes), blepharoptosis (16% of eyes), telecanthus (13% of children), nystagmus (1 child), and cataract (1 eye). Ocular fundus photography analysis showed retinal vessel tortuosity in 30% of the eyes and optic disc hypoplasia in 25%. The mean DM/DD for the control and FAS groups was 2.72 +/- 0.20 and 2.89 +/- 0.25 (p=0.001). Forty percent of the eyes of FAS children had small optic discs. CONCLUSIONS: The most common ocular findings were anomalies of retinal fundus and minor changes in the outer region of the eyes. The authors noted better VA and less severity of disease than others, which might be due to a different selection of patients, different pattern of alcohol consumption, or genetic differences.     

Correlation between optic nerve head parameters and retinal nerve fibre layer thickness measured by spectral-domain optical coherence tomography in myopic eyes

Background: To evaluate the correlation between optic nerve head parameters and retinal nerve fiber layer thickness measured by Cirrus HD spectral‐domain optical coherence tomography (Cirrus HD‐OCT; Carl Zeiss Meditec) in healthy myopic eyes. Design: Cross‐sectional study. Participants: One hundred and sixty‐one right eyes from 161 healthy young myopic subjects. Methods: Optic nerve head parameters and retinal nerve fiber layer thickness were measured with the Cirrus HD‐OCT. The distance between optic disc margin and scan circle (disc margin‐to‐scan distance) was measured on the Cirrus HD‐OCT en‐face optic nerve head image with aid of National Institutes of Health ImageJ image‐analysis software (developed by Wayne Rasbands, National Institutes of Health, Bethesda, MD). Main Outcome Measures: The correlations among optic nerve head parameters, retinal nerve fibre layer thickness and the disc margin‐to‐scan distance were evaluated with and without adjustment of the magnification effect. Results: Without correction of the magnification effect, the thicker average retinal nerve fiber layer was correlated with greater rim area and lower degree of myopia (P < 0.001). When the magnification effect was corrected, thicker average retinal nerve fibre layer was associated with greater disc area and greater rim area in univariate and multivariate analyses (P ≤ 0.028); however, degrees of myopia and the disc margin‐to‐scan distance were not significantly associated with average RNFL thickness (P ≥ 0.104). Conclusions: Thicker average retinal nerve fibre layer thickness was associated with greater rim and disc areas. Disc margin‐to‐scan distance was not significantly correlated with average retinal nerve fibre layer thickness in healthy myopic eyes.     

Laser scanning tomography of the optic nerve head in a normal elderly population: the Bridlington eye assessment project

PURPOSE: To assess optic nerve head topographic parameters using the Heidelberg Retina Tomograph (HRT) II (Heidelberg Engineering GmbH, Dossenheim, Germany) in a normal elderly population. METHODS: Optic nerve head analysis of 918 eyes of 459 normal elderly patients was performed. All patients were consecutive in a cohort screened for eye disease. Normal subjects were defined with a normal visual field on automated suprathreshold screening, intraocular pressure less than 22 mmHg, and minimum corrected visual acuity of 6/12. All optic discs were contoured by two investigators and the mean parameters analyzed. The effects of age, sex, and disc size were assessed. RESULTS: Subjects' (262 women and 197 men) mean age was 72.6 +/- 5.1 (SD) years (range, 65.5-89.3). Mean +/- SD global disc area, cup/disc area ratio, and neuroretinal rim area were 1.98 +/- 0.36 mm2, 0.22 +/- 0.14, and 1.52 +/- 0.31 mm2, respectively. Disc area did not differ significantly based on eye side or sex. The women were found to have a significantly larger rim volume, mean retinal nerve fiber layer (RNFL) thickness, and cross-sectional area than the men and tended to have smaller cup areas/volumes and cup/disc area ratios. Most tomography parameters were found to be significantly influenced by disc size. CONCLUSIONS: To the authors' knowledge, this is the first large study of optic nerve head parameters in the elderly normal population using the HRT II. This age range is particularly relevant to glaucoma detection and pertinent to discriminant analyses separating normal subjects from glaucoma in screening for the disease. Given the systematic differences between the parameters in men and women, reference ranges should be quoted by sex.     

Macrodisks with physiologic macrocups (pseudo-glaucoma disks). Papillometric characteristics in 17 eyes

Characteristics of 17 optic disks larger than 4.4 mm2 and thus satisfying the papillometric criteria of macrodisks (larger than normal optic disks plus two-fold standard deviation) were as follows: (1) Form: similar to normal optic nerve heads but even more circular. The vertical diameter was about 6% larger than the horizontal. (2) Optic cup: abnormally large, therefore "pseudoglaucomatous." (3) Neuroretinal rim: normal-sized when correlated to the total optic disk area, larger in the temporal lower than in the temporal upper optic disk region, narrowest on the temporal optic disk side, larger nasally at the top, and widest at the upper optic disk pole. (4) Cup/disk ratio: abnormally high (0.76 +/- 0.06 horizontally, 0.69 +/- 0.05 vertically), larger horizontally than vertically. (5) Perimetry: the only abnormality was an increased blind spot corresponding to the enlarged optic disk area. (6) Refraction. -0.25 +/- 1.90 diopters (high myopics less than -8.00 diopters) had been excluded). (7) Central retinal artery and vein penetrating the superficial lamina cribrosa almost at the center of the cup, bayonetlike vessel bending at the border of the optic cup. (8) Increased number of cilioretinal arteries, corresponding to their correlation with the optic disk area. These macrodisks with physiologic macrocups can be differentiated by their morphology or by optic disk planimetry in absolute values from: normal-sized optic nerve heads with glaucomatous cupping, abnormally large optic nerve heads in highly myopic eyes, and abnormally large optic nerve heads with pitting of the optic disk.     

海德堡视网膜断层扫描仪测量正常人视盘参数

目的 :建立正常人群海德堡视网膜断层扫描仪 (Heidelbergretinatomograph ,HRT)视盘参数的正常值 ,明确哪些因素对正常人HRT视盘参数有影响。方法 :选用 10 2例 (13 2只眼 )正常人 ,用HRT进行视盘扫描 ,视盘参数包括视盘面积、视杯面积和容积、盘沿面积和容积、视杯形态、视杯平均深度和最大深度、杯 /盘面积比、沿 /盘面积比、平均视网膜神经纤维层(retinalnervefiberlayer,RNFL)厚度和横截面积、水平C/D和垂直C/D。计算正常人视盘参数范围 ,用直线回归的方法判断视盘大小和年龄对视盘参数的影响。结果 :正常人左右眼和男女间视盘各参数差异无显著意义 (P >0 0 5)。年龄与RNFL厚度及横截面积呈负相关 ,相关系数分别为 -0 2 3 4和 -0 2 3 5,其余各参数与年龄无关。盘沿容积和视杯最大深度不受视盘大小的影响 ,其余各参数均与视盘大小呈线性相关。结论 :HRT可定量检测正常人视盘参数 ;正常人视盘参数变异很大 ,盘沿容积不受视盘大小的影响 ,是一个区分正常与早期青光眼的很好的参数     

Normal retinal nerve fiber layer thickness in the peripapillary region measured by scanning laser polarimetry.

PURPOSE: To measure retinal nerve fiber layer thickness (RNFLT) as a function of distance from the optic nerve head using a confocal scanning laser polarimeter, such as the Nerve Fiber Analyzer (GDx). METHODS: Twenty eyes of 20 healthy patients were recruited for this study. Each patient had a normal visual field and a healthy optic nerve head, which was assessed by slit-lamp biomicroscopy using a 90-diopter lens and by a scanning laser ophthalmoscope. Using the GDx, RNFLT was calculated from 1.1 disc diameters (DD) to 2.5 DD in 0.1-DD increments from the outer edge of the optic disc rim. RNFLT was successively evaluated for the entire annulus surface, for each quadrant, and for every 10 degree sector. RNFLT was calculated in retardation degrees. Differences in RNFLT were calculated by analysis of variance. RESULTS: When the entire RNFLT was considered, the measurements close to the optic nerve head (at 1.1 and 1.2 DD) were found to be significantly (0.05 < or = P < or = 0.01) different from those measured far from the disc (at 2.4 and 2.5 DD). The inferior quadrant had the greatest RNFLT followed by the superior quadrant. When RNFLT was analyzed for every 10 degrees, RNFLT at 1.1 and 1.2 DD was significantly (P < or = 0.001) different from that measured at 2.4 and 2.5 DD in almost all 36 sectors. In the 36 considered sectors, no significant difference was found for all the RNFLT values that were calculated in all the positions of the annulus surface between 1.1 and 1.7 DD. CONCLUSION: From these data, peripapillary RNFLT is shown to be significantly (P < or = 0.001) thinner in the periphery (2.5 DD) than around the optic disc (1.1 DD). However, the lack of any difference in RNFLT from 1.1 to 1.7 DD suggested that the mild variations to locate the optic disc contour line do not change the results of the analysis if the RNFLT is calculated within 1.8 DD.     

Development of the standard reference plane for the Heidelberg retina tomograph

Background: Topometry of the optic disc is the quantitative assessment of the structure of the optic nerve head by means of three- dimensional parameters. The parameter values depend on definitions of intraocular reference planes. Purpose: To describe the development of intraocular reference planes in laser scanning tomography for the Heidelberg Retina Tomograph (HRT) using image intrinsic data with a fixed offset reference plane (320 μm) and to present a contour-line-based ”flexible” standard reference plane (”SRP”) for calculation of intrapapillary stereometric parameters taking the interindividual variability of optic disc topography into account.Methods: Ten-degree triple images were obtained by laser scanning tomography from 99 glaucoma eyes and 180 normal eyes. The images were evaluated to assess the variability of height measurements of an optic disc border contour-line segment (6° width) corresponding to the site of the papillo-macular bundle as indicated by the average optic disc surface inclination angle. Results: The average optic disc surface inclination angle was –7°±3° below the horizontal meridian (0°). The 6° wide contour-line segment for the SRP was chosen according to the average surface inclination angle (–10° to –4°). The reproducibility of the SRP-segment height measurements was 16.0±10.8 μm for normal eyes and 23.4±18.0 μm for glaucoma eyes. To ensure that the automatic reference level determination for intrapapillary parameters remained below the disc border height, we defined the SRP level at a 50 μm offset (>2 SD of average segment height reproducibility in glaucoma) added to the individual height position of the 6° contour line segment. Conclusion: The flexible standard reference plane allows for automatic determination of intrapapillary variables once a disc border contour line is interactively defined. In contrast to a fixed offset reference plane (e.g. 320 μm below the mean retina height), the interindividual variability of optic disc topography (oblique insertion, glaucomatous surface flattening) is respected at the cost of the need for an accurate optic disc border outline. Received: 9 March 1999 Revised: 26 August 1999 Accepted: 29 September 1999     

非动脉炎性前部缺血性视神经病变视盘形态变化及其对视觉功能的影响

目的应用形态测量学方法评估非动脉炎性前部缺血性视神经病变（NAION）患者杯／盘直径比（C／D）和视神经乳头旁α区和β区的变化,探讨视盘形态变化与NAION的关系。方法选取154例单眼或双眼发病NAION患者,采用德国CarlZeiss公司Humphrey2000型OCT检查系统连续拍摄视盘形态,对数据进行统计学分析和处理。结果随访时间为12个月。水平扫描和垂直扫描视盘直径分别为（P=0．30,P=0．61）,水平扫描和垂直扫描C／D比分别为（P=0．47,P=0．19）,乳头旁α区和β区分别为（P=0．27,P=0．32）。单眼NAION组患眼和对侧眼之间无明显差异。单侧NAION组和双侧NAION组未受影响眼之间,水平扫描和垂直扫描视盘直径、水平扫描和垂直扫描C／D比、与α区和β区比较无显著差异（P〉0．05）。NAION组患眼视力、视盘直径、C／D比、视盘旁α区或β区无显著相关性（P〉0．20）,单侧NAION组患眼和对侧眼视力之间无显著差异（全部P〉0．25）。结论NAION组不影响C／D比值,也不影响视盘旁α区和β区。视盘形态大小与NAAION组视力无相关性。     

光学性旋转隐斜

目的　为证实斜轴散光会引起光学性旋转隐斜。方法　对 48例无斜视和眼部手术史 ,且眼球运动正常的 5～ 1 3岁儿童进行屈光检查 ,以有无斜轴散光分为正常组和斜轴散光组 ,同时眼底照相 ,测量、比较被检眼视盘几何中心和黄斑中心凹的相对位置。结果　正常眼黄斑中心凹—视盘夹角表现为外旋 ,平均 5 698° ,其中 2 0只非散光眼为 5 70 1° ,2 2只正轴散光眼为 5 695°。斜轴散光眼之夹角为外旋 ,平均 1 0 91 6° ,明显大于正常组。而且斜轴偏斜度越大 ,旋转隐斜度也越大。结论　斜轴散光眼多产生习惯性光学性旋转隐斜 ,由此而导致的临床不适 ,应引起眼科医师重视     

Optic disc morphology after arteritic anterior ischemic optic neuropathy

OBJECTIVE: To evaluate the appearance of the nerve head in patients after giant cell arteritis-induced arteritic anterior ischemic optic neuropathy (A-AION). DESIGN: Noncomparative clinical case series. PATIENTS: The study comprised 29 patients who presented with unilateral A-AION and temporal artery biopsy-proven giant cell arteritis. Stereoscopic optic disc photographs, taken of both the affected and unaffected eyes at the onset of the disease and after a follow-up period of 20.10 +/- 25.36 months (median, 11 months; range, 2-102 months), were morphometrically evaluated. MAIN OUTCOME MEASURES: Size and shape of the optic disc, neuroretinal rim, optic cup, and alpha and beta zones of parapapillary atrophy. RESULTS: In the eyes after A-AION, at the end of the study, the neuroretinal rim was significantly (P = 0.002) smaller, and the optic disc cup area was significantly (P = 0.001) larger than those of the contralateral unaffected eyes. Alpha zone and beta zone of parapapillary atrophy did not vary significantly (P > 0.50). CONCLUSIONS: A-AION, like glaucomatous optic neuropathy, results in neuroretinal rim loss and optic disc cupping. However, in contrast to glaucoma, A-AION is not associated with an enlargement of parapapillary atrophy. The reasons and mechanisms responsible for these similarities and dissimilarities are discussed. Marked clinical, morphologic, and histopathologic similarities in optic disc cupping and loss of neuroretinal rim between A-AION and glaucomatous optic neuropathy are highly suggestive of a common mechanism for the development of the two diseases (i.e., ischemia of the optic nerve head). The subject is discussed at length.     

Dysversion of the optic disc and axial length measurements in a presumed amblyopic population.

PURPOSE: Our purpose was to evaluate anatomic variations of eyes presumed to be amblyopic. METHOD: Computer imaging and photography of the optic discs of 205 amblyopic subjects were performed and the axial lengths of 183 of the subjects were measured. The paired optic nerve images were evaluated for symmetry of disc contours and orientation of central blood vessels to detect optic nerve head dysversion. Dysversion of the optic nerve head, which is also referred to as segmental hypoplasia, is a congenital disorder characterized by the central retinal vessels emerging temporal to the vertical midline of the disc and being directed nasally or the nerve head tilting in a vertical direction resulting in a downward or oblique tilting of the discs with the blood vessels emerging at the superior or inferior disc rim. RESULTS: Ninety-three subjects had optic nerve dysversion. There was a greater degree of anisometropia (P< or =.004) in subjects with dysversion (anisometropia factor of 2.51+/-2.15) than in the subjects with symmetric discs (anisometropia factor of 1.76+/-1.63). Axial lengths of the amblyopic eyes were significantly smaller (P<.0001) than those of the nonamblyopic eyes. There was no statistical difference (P< or =.879) in length between amblyopic eyes with dysversion and those with symmetric discs. CONCLUSION: Optic disc dysversion was identified in 45.4% of patients who were previously assumed to be amblyopic. There are anatomic malformations in the eyes of a significant proportion of the presumed amblyopic population. This suggests that, in these individuals, congenital peripheral factors rather than impaired cortical development may be responsible for decreased unilateral acuity.