Congenital anomalies of the optic disc

Although anomalies affecting the optic nerve head are usually clinically innocuous, they can sometimes cause significant symptoms and lead to visual loss. It is important to be able to recognize even the relatively benign lesions in order to differentiate them from other more threatening lesions or disease processes which they may clinically resemble. An awareness of the clinical appearance of disc anomalies is especially important in the differential diagnosis of optic nerve glaucomatous changes. Some anomalies cause various types of visual field loss which, if the actual disc lesion is not recognized, may lead to unnecessary neurologic evaluation or even to intracranial surgery. The optic nerve changes in acquired myopia and in the congenital tilted disc syndrome should be clearly defined and differentiated: high (pathologic) myopia may be highly progressive with many dangerous secondary sequelae, while the latter anomaly is stationary. Finally, there is a group of conditions, collectively termed “elevated anomalies of the disc,” which must be considered in the differential diagnosis of papilledema and potentially dangerous intraocular tumors, particularly retinoblastoma. This review provides a clinicopathologic correlation comparing the characteristics of the normal optic disc to those of the most important congenital anomalies of the disc.     

Retinal detachment associated with optic disc colobomas and morning glory syndrome

We report the diagnosis and treatment of patients with retinal detachment and/or retinoschisis associated with optic nerve coloboma or morning glory syndrome. A retrospective review of patients with optic nerve coloboma or morning glory syndrome with associated retinal detachment or retinoschisis was conducted. For five patients (six eyes), we report the clinical findings, spectral domain optical coherence tomography (OCT) imaging, intraoperative findings, and treatment outcomes. OCT scans demonstrate a bilaminar structure of maculopathy, consisting of inner schisis-like changes and outer layer retinal detachment. In most cases, a retinal break was demonstrated within the optic disc defect with three-dimensional OCT imaging. Glial tissue was sometimes observed within the anomalous defect. Vitrectomy and resection of the tractional tissue in these cases produced good anatomical and visual outcomes. Retinal detachment spontaneously resolved in cases where traction was not present. Traction may contribute to the pathogenesis of retinal detachment associated with colobomatous optic disc anomalies, either directly or by creating a secondary retinal break. OCT imaging assists with understanding the contributing factors to retinal detachment in individual cases of colobomatous optic disc anomalies and can thereby assist with determining the most effective approach to management.     

Retinal nerve fiber layer analysis and interpretation of GDx parameters in patients with tilted disc syndrome

This study was conducted to determine abnormalities of the GDx Glaucoma Scanning System parameters in patients with tilted discs, in order to set guidelines for the evaluation of glaucomatous damage in this situation. The objective was to determine which GDx parameters displayed the highest level of variation, and which remained unchanged in tilted disc syndrome. RNFA was polarimetrically conducted on 45 eyes from 26 subjects with tilted discs, and 43 normal eyes withNerve Fiber Analyzer II (Laser Diagnostic Technologies). All parameters except inferior maximum, average thickness, ellipse average, and inferior average displayed a significant difference between the two groups (p < 0.05). Although NFA is useful in glaucoma diagnosis, the majority of the GDx parameters, as shown in our study, are unreliable in tilted disc syndrome in this respect.     

Five rules to evaluate the optic disc and retinal nerve fiber layer for glaucoma.

A systematic approach for the examination of the optic disc and retinal nerve fiber layer is described that will aid in the detection of glaucoma. This approach encompasses 5 rules: evaluation of optic disc size, neuroretinal rim size and shape, retinal nerve fiber layer, presence of parapapillary atrophy, and presence of retinal or optic disc hemorrhages. A systematic process enhances the ability to detect glaucomatous damage as well as the detection of progression, and facilitates appropriate management.     

青光眼与非炎症性缺血型视神经病变的傅立叶OCT扫描视神经形态学对比

目的 比较青光眼与非炎症性缺血型视神经病变(non-arteritic ischemic optic neuropathy,NAION)患者患眼的视盘及盘周视网膜神经纤维层(peripapillary retinal nerve fiber layer,pRNFL)参数变化情况及诊断能力.方法 选择我院眼科年龄≥40岁就诊患者71例(71眼).受试者分为青光眼组26例、NAION组15例、对照组30例,排除视野缺损范围大于两个象限或等效球镜度数大于±6D的受试眼以及发病时间小于6个月的NAION患眼.所有患者均接受眼部常规检查,使用傅立叶OCT测量视盘及pRNFL各参数.结果 3组之间除视盘面积外(P =0.059),其余视盘及pRNFL各参数差异均有统计学意义(均为P＜0.05).经LSD两两比较发现:青光眼组的视杯面积(1.438±0.714)mm2最大(均为P ＜0.05),盘沿面积(0.965 ±0.652)mm2最小(均为P＜0.05),盘沿容积和视神经盘容积[(0.103 ±0.089)mm3、(0.195±0.168)mm3]最小(均为P＜0.05),视杯容积(0.482 ±0.420)mm3最大(均为P ＜0.05),杯盘比最大(均为P＜0.05);NAION组的视杯面积(0.493±0.344) mm2最小(均为P＜0.05),盘沿面积(1.255±0.294) mm2与对照组(1.243±0.509) mm2差异无统计学意义(P＞0.05),盘沿容积(0.196±0.094)mm3、视神经盘容积(0.339±0.109) mm3与对照组差异均无统计学意义(均为P＞0.05),视杯容积(0.083 ±0.073)mm3最小(均为P＜0.05),杯盘比最小(均为P＜0.05).在pRNFL方面,经LSD两两比较发现:3组在平均值及TU、ST、SN、NU、IT区之间两两比较差异均有统计学意义(均为P＜0.05);在NL、IN、TL区,青光眼组与对照组两两比较差异均有统计学意义(均为P ＜0.05).将青光眼组与对照组进行AROC分析发现:视盘参数中除视盘面积外(P＞0.05),其他参数及所有pRNFL各参数差异均有统计学意义(均为P＜0.05).将NAION组与对照组进行AROC分析发现:pRNFL中的上方(即ST、SN区)、鼻上(即NU区)和下方偏颞侧(即IT区)AROC差异均有统计学意义(均为P＜0.05),视盘所有参数及pRNFL其余部位差异均无统计学意义(均为P ＞0.05).将NAION组与青光眼组进行AROC分析发现:视盘参数中视杯面积、视杯容积、杯盘比(包括面积、水平和垂直)的AROC差异均有统计学意义(均为P＜0.05),而pRNFL中的颞上方(即TU区)、鼻上方(即NU区)和平均值AROC差异均有统计学意义(均为P＜0.05),其余部位差异均无统计学意义(均为P＞0.05).结论 通过傅立叶OCT检测可发现青光眼与NAION在视盘及pRNFL方面的差异,为理解此两种视神经疾病的发病特点及鉴别诊断提供临床依据.     

Optical coherence tomographic findings in optic nerve hypoplasia

We investigated a case of unilateral optic nerve hypoplasia using spectral domain optical coherence tomography (SDOCT). Optical coherence tomography was done on both eyes using 5-line Raster scan for the fovea to analyze the retinal nerve fiber layer thickness, inner retinal layer thickness, outer retinal layer thickness, and optic disc cube scan for the disc. Retinal nerve fiber layer thickness, inner retinal layer thickness, and outer retinal layer thickness were manually measured at 21-points of each five lines, and results were compared between both eyes. Retinal nerve fiber layer thickness and inner retinal layer thickness of optic nerve hypoplasia were significantly thinner than the opposite eye, but there was no significant difference in the thickness of the outer retinal layer between both eyes.     

Analyses of shape of eyes and structure of optic nerves in eyes with tilted disc syndrome by swept-source optical coherence tomography and three-dimensional magnetic resonance imaging

Purpose

To evaluate the deeper structures of the optic nerve and to analyze the shape of eyes with tilted disc syndrome (TDS) by swept-source optical coherence tomography (OCT) and three-dimensional magnetic resonance imaging (3D MRI).

Methods

The medical records of 54 eyes of 36 patients with TDS were reviewed. The patients with TDS and high myopia were analyzed separately from those without high myopia. All the eyes were examined with a swept-source OCT, and 22 of the eyes were examined by 3D MRI.

Results

A total of 38 eyes of 29 patients were highly myopic and 16 eyes of 15 patients were not highly myopic. The representative OCT findings of the optic disc were: a sloping of the lamina cribrosa posteriorly from the upper part to the lower part, a protrusion of the upper edge of Bruch''s membrane, and choroid. The distance and the depth of the most protruded point from the fovea were significantly greater in the eyes with non-highly myopic TDS than those with highly myopic TDS. In the 3D MRI, the lower part of the posterior segment was protruded outward, and the optic nerves attached at the upper nasal edge of the protrusion.

Conclusions

The abnormalities detected by swept-source OCT and 3D MRI analyses indicate the possibility that the essential pathology of TDS is a deformity of the inferior globe below the optic nerve, and the positional relation between the fovea and the inferior protrusion determines the degree of myopia.     

Retinal nerve fiber layer and optic disc measurements by spectral domain OCT: normative values and associations in young adults

Purpose

To determine normative values and associations of retinal nerve fiber layer (RNFL) and optic disc parameters in normal eyes measured by spectral domain optical coherence tomography (OCT).

Methods

In a population-based setting, 1521 young adults were examined as part of the Sydney Adolescent Vascular and Eye Study (SAVES). Their mean age was 17.3±0.6 years. RNFL and optic disc parameter measurements were made using Cirrus HD-OCT 4000.

Results

The average RNFL was found to be 99.4±9.6 μm. RNFL thickness was least for the temporal quadrant (69.9±11.2 μm), followed by the nasal (74.3±12.8 μm), superior (124.7±15.7 μm) and inferior (128.8±17.1 μm) quadrants. The mean disc area in this population was 1.98±0.38 mm² with a mean rim area of 1.50±0.30 mm² and a mean cup/disc ratio of 0.44±0.18. Multivariate-adjusted RNFL thickness was marginally greater in East Asian than in white participants (100.1 μm vs 99.5 μm; P=0.0005). The RNFL was thinner with greater axial length (P<0.0001), less positive spherical equivalent refractions (P<0.0001), smaller disc area and rim area (P<0.0001).

Conclusion

This study documents normative values for the RNFL and optic disc measured using Cirrus HD-OCT in young adults. The values and associations reported in this study can inform clinicians on the normal variation in RNFL and optic disc parameters.     

Retinal tomographic measurements in optic disc pit

Background: The aim was to assess the Heidelberg Retina Tomograph II measurements in optic disc pit. Methods: The study included 10 patients with a unilateral optic disc pit. The patients had no other ocular conditions except refractive errors. Normal fellow eyes of the patients were used as a control group. Optic nerve head topographic analyses were performed using a confocal scanning laser ophthalmoscope, Heidelberg Retina Tomograph II (HRT II). Results: The topographic parameters of the eyes with optic disc pit and normal fellow eyes were as follows, respectively: disc area (3.77 ± 1.50 and 3.07 ± 0.83 mm²), cup area (1.99 ± 1.71 and 1.09 ± 0.54 mm²), rim area (1.67 ± 0.55 and 1.87 ± 0.75 mm²), cup volume (0.94 ± 1.24 and 0.34 ± 0.27 mm³), rim volume (0.51 ± 0.40 and 0.55 ± 0.19 mm³), mean cup depth (0.44 ± 0.20 and 0.31 ± 0.11 mm) and mean retinal nerve fibre layer thickness (0.25 ± 0.20 and 0.28 ± 0.59 mm). Eyes with an optic disc pit were found to have significantly larger disc area compared to fellow eyes (p = 0.038). All the other parameters showed no statistically significant interocular differences (p > 0.05). Conclusion: Our study demonstrates that the optic disc pit affects only the disc area measurement in HRT II. Other changes in optic nerve head morphometric parameters were insignificant. The clinician must be careful in the evaluation of HRT II results with respect to optic disc area in a disc with a pit.     

Electrophysiologic findings in optic nerve dysfunction associated with multiple evanescent white-dot syndrome

Electrophysiologic findings in a case of multiple evanescent white-dot syndrome were studied. A 37-year-old woman presented with multiple white dots, granularity of the macula, and optic disc swelling in her left fundus. The electroretinogram and electro-oculogram revealed abnormal findings indicative of changes in the retinal pigment epithelium and photoreceptors. In addition, relative afferent pupillary defect, enlargement of the blind spot, a decrease in the critical fusion frequency, staining of the optic disc on fluorescein angiography and prolonged latency of the P100 component with decreased amplitude in pattern-reversal visual evoked cortical potential strongly suggested dysfunction of the optic nerve in this patient.Abbreviations MEWDS multiple evanescent white-dot syndrome     

Fluids in the anterior part of the optic nerve in health and disease

New techniques have recently made it possible to study the flow of fluids (blood, axoplasm, and interstitial fluid) in the anterior part of the optic nerve. Blood flow has been reviewed previously; axoplasm and interstitial fluid are considered in this review. General concepts of axoplasmic transport (anterograde and retrograde) are outlined, and the role of axoplasmic transport in the pathogeneses of optic disc edema of various types, in glaucoma, and in ischemic and toxic optic neuropathies is discussed. The probable sources of interstitial fluid in the anterior part of the optic nerve are capillaries in the nerve itself, peripapillary choroid, vitreous, cerebrospinal fluid and possibly axoplasm in the local axons; the flow is defined by various barrier systems. The role of the interstitial fluid in the pathogeneses of optic disc edema (and associated phenomena) and in serous retinal detachment in the macular region associated with optic disc pit is discussed. Its involvement in the process of diffusion of retrobulbar medication into the optic nerve and vitreous is also considered.     

Superior segmental optic nerve hypoplasia in youth

Purpose  The clinical characteristics of superior segmental optic nerve hypoplasia (SSOH) in youth were investigated to help establish diagnostic criteria. Methods  Eleven eyes of seven young patients (male/female ratio, 3/4; age, 15.1 ± 3.4 years) who had good visual acuity and inferior visual field defects (VFDs) were evaluated. Goldmann and Humphrey perimetries and optic disc morphology were analyzed, and the patients were prospectively followed for a long period. Results  Visual field defects were wedge shaped and oriented to the blind spot, but discontinuous in mild cases. Nerve fiber layer defects (NFLDs) were consistent with the VFDs. The optic disc appearance was variable, with double ring signs in seven eyes, small discs in three eyes, and an incomplete topless disc in one eye. The mothers of none of the patients had gestational diabetes. Visual field defects did not progress during the prospective 8.3 ± 1.3 years follow-up. Conclusions  Characteristic VFD patterns on Goldmann perimetry and corresponding NFLDs are important in the diagnosis of SSOH, but not optic disc morphology.     

Relation between size of optic disc and thickness of retinal nerve fibre layer in normal subjects

AIMS—To evaluate the relation between the optic disc size and the thickness of the peripapillary retinal nerve fibre layer (RNFL) in normal Japanese subjects by means of scanning laser polarimetry.
METHODS—Scanning laser polarimetry was performed in 60 normal subjects. One eye of each subject was randomly selected for study. Using a scanning laser polarimeter, the integral of RNFL thickness was measured totally and regionally within a circular band located 1.75 disc diameters from the centre of the optic disc. The correlation between the optic disc size and the integral of RNFL thickness was examined.
RESULTS—The optic disc size showed a significant correlation with the integral of RNFL thickness (R = 0.497, p <0.001). A significant negative correlation was observed between the optic disc size and the ratio of inferior integral to total integral of RNFL thickness (R = −0.274, p = 0.034).
CONCLUSIONS—The cross sectional area occupied by the RNF, measured by scanning laser polarimetry increased significantly with an increase in optic disc size while the ratio of inferior to total cross sectional area decreased significantly. These facts should be considered when one evaluates the RNFL thickness in patients with progressive optic neuropathies such as glaucoma.

Keywords: scanning laser polarimeter; normal subjects; optic disc; retinal nerve fibre layer     

放射状视神经切开手术机制的初步研究

目的:观察猫眼行放射状视神经切开术 (radial opticneurotomy,RON) 后视盘结构的改变,探讨 RON 的临床机制。方法:健康成年猫共 18 只,为术后 1d 组、术后 15d 组、术后 30d 组和术后 90d 组。术后 1d 组为 6 只。单眼行放射状视神经切开术。分别于术后 1,15,30,90d 取材,组织切片特染检查。结果:RON 术后 1d 巩膜切口呈“一”型裂开,手术间隙与蛛网膜下腔相通,伴少量出血及炎细胞浸润;15～30d 切口呈“枣核”型,神经胶质细胞增殖,胶原纤维沿切口缘环形增生,增生胶原以 III型为主,筛孔呈长裂隙状;90d 瘢痕组织将筛板和巩膜切口完全填充,I 型和 III 型胶原排列不规则,边缘的筛孔形态恢复。结论:手术可将视盘周围的巩膜环及视神经眼内段软脑膜锐性切开,切口在巩膜环处呈逐渐扩宽趋势并与蛛网膜下腔相通,这可能是 RON 减轻临床症状机制之一。     

B-scan ultrasonography in optic nerve lesions

After a short introduction to the method used in the Royal Dutch Eye Hospital in Utrecht, for B-scan ultrasonography with Coleman's apparatus, the normal echo pattern of the optic nerve and a number of abnormalities are considered. Excavation or prominence of the disc can be established, even when the media are opaque. In retrobulbar neuritis, certain anomalies in the echo pattern are found in a high percentage of cases, as one of the few objective changes in this condition. Leber's optic atrophy appears to give a typical echo pattern. The echographic pictures of a glioma of the optic nerve and of displacement of the optic nerve, probably due to a metastasis from a cutaneous melanoma, are described.     

Central Retinal Vein Occlusion in a Childhood Optic Nerve Tumour

The authors describe the first paediatric patient with an aggressive optic nerve tumour of uncertain histology causing a central retinal vein occlusion, retinochoroidal collaterals, arteriovenous anastomoses, and peripheral retinal non-perfusion. He first presented with pale optic nerve head, followed by development of optic disc oedema a year later. Certain optic nerve tumours can present with central retinal vein occlusion in the paediatric age group.     

视神经保护的研究进展

视神经作为中枢神经的代表,它的再生和保护机制近年来得到深入而广泛的研究,视神经损伤后对视网膜神经节细胞的保护主要是停止或防止其发生凋亡,主要途径有:谷氨酸抑制剂、一氧化氮抑制剂、神经营养因子、基因治疗、针灸、中药等。但是迄今还没有一种药物或手术方法对视神经损伤的修复有明确的疗效。视神经保护仍处于研究探索阶段,任重而道远。