Evaluating the Optic Disc and Retinal Nerve Fiber Layer in Glaucoma I: Clinical Examination and Photographic Methods

Glaucoma is a leading cause of blindness worldwide and is characterized in part by specific changes in the optic disc and retinal nerve fiber layer. Currently, subjective clinical examination and fundus photography are the most common ways of detecting structural change in glaucoma and monitoring its progression. In the first part of this two-part article, the authors overview structural changes of the optic disc and retinal nerve fiber layer in glaucoma and describe and evaluate photographic methods for observing these changes. In the second part of this article (this issue), recent developments in computer-based optical imaging techniques that allow objective evaluation of the optic disc and retinal nerve fiber layer are described     

Imagings of glaucoma: characteristics of ocular configurations and automated diagnosis

Glaucoma is characterized by the coexistence of structural changes in the fundus and the corresponding functional abnormalities. The advances in imaging devices that reveal structural changes in glaucoma should facilitate reliable diagnosis of early or preperimetric glaucoma and a proper evaluation of glaucoma progression. Moreover, the increase in our knowledge of structural changes in glaucoma will provide a better platform for investigating up to now unknown glaucoma etiologies. In this review, we summarize a series of our clinical investigations of glaucoma imaging technologies. The diagnostic performance of Heidelberg Retina Tomograph (HRT) II and the characteristics of the HRT II parameters in high myopia were studied with population-based data to provide data for nerve head configuration; the correlation of parameters determined by planimetry of optic disc stereophotography with the results of the HRT II was evaluated; optic disc parameters were determined based on spectral-domain optical coherence tomography (SD-OCT); and optic disc configurations were evaluated in eyes with peripapillary atrophy and eyes with superior segmental optic nerve hypoplasia. Peripapillary retinal nerve fiber layer (RNFL) thickness was determined with SD-OCT in normal Japanese eyes; and the diagnostic performance of RNFL thickness was studied. The characteristics of each layer, including retinal nerve fiber layer, ganglion cell layer, and each complex layer in the macular area, and their correlation with the stages of glaucoma were evaluated. Finally, imaging of the anterior chamber angle using ultrasound biomicroscopy (UBM) were studied about the distribution of the UBM parameters in a Japanese population and the factors relating to the presence of peripheral anterior synechia in narrow angle eyes.     

Optic nerve head appearance in juvenile-onset chronic high-pressure glaucoma and normal-pressure glaucoma

OBJECTIVE: To evaluate the appearance of the optic nerve head in chronic high-pressure glaucoma and normal-pressure glaucoma. DESIGN: Clinic-based cross-sectional study. PARTICIPANTS: The study included 52 eyes with normal-pressure glaucoma and 28 eyes with juvenile-onset primary open-angle glaucoma that served as models for chronic high-pressure glaucoma. METHODS: Color stereo optic disc photographs and wide-angle retinal nerve fiber layer photographs were morphometrically examined. MAIN OUTCOME MEASURES: Localized retinal nerve fiber layer defects; parapapillary chorioretinal atrophy; disc hemorrhages; optic cup shape; retinal arteriole narrowing. RESULTS: Both study groups did not vary significantly in count of localized retinal nerve fiber layer defects, size of parapapillary atrophy, optic cup depth, steepness of disc cupping, rim/disc area ratio, diameter of retinal arterioles, and frequency and degree of focal retinal arteriole narrowing. In normal-pressure glaucoma versus juvenile open-angle glaucoma, localized retinal nerve fiber layer defects were significantly broader, disc hemorrhages were found significantly more often and were larger, and neuroretinal rim notches were present more frequently and were deeper. CONCLUSIONS: Chronic high-pressure glaucoma and normal-pressure glaucoma show morphologic similarities in the appearance of the optic nerve head. The lower frequencies of detected disc hemorrhages and rim notches in high-pressure glaucoma may be due to a smaller size of hemorrhages and localized retinal nerve fiber layer defects in high-pressure glaucoma. Both glaucoma types have morphologic features in common, suggesting that they may possibly belong to a spectrum of the same pathologic process.     

Evaluating the optic disc and retinal nerve fiber layer in glaucoma. II: Optical image analysis

Glaucoma is a widespread, blindness-causing disease that is characterized in part by specific and sometimes subtle changes in optic disc and retinal nerve fiber layer topography. Several recently developed computer-based optical imaging techniques allow objective evaluation of the optic disc and retinal nerve fiber layer. These techniques use different optical properties and different properties of the retina to provide micron scale measurements of many aspects of optic disc and retinal nerve fiber layer structure. This article describes and evaluates 3 of these techniques: confocal scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography.     

Evaluating the Optic Disc and Retinal Nerve Fiber Layer in Glaucoma II: Optical Image Analysis

Glaucoma is a widespread, blindness-causing disease that is characterized in part by specific and sometimes subtle changes in optic disc and retinal nerve fiber layer topography. Several recently developed computer-based optical imaging techniques allow objective evaluation of the optic disc and retinal nerve fiber layer. These techniques use different optical properties and different properties of the retina to provide micron scale measurements of many aspects of optic disc and retinal nerve fiber layer structure. This article describes and evaluates 3 of these techniques: confocal scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography     

OCT测量视网膜神经纤维层厚度及视盘参数在青光眼早期诊断中的应用

青光眼是一种进行性视神经疾病,它能引起视神经结构改变,最终导致不可逆的视功能损害。青光眼的早期诊断对保护视功能有重要意义。光学相干断层扫描仪是一种准确性和可重复性高的视网膜神经纤维层厚度和视盘参数检测技术,为早期诊断青光眼,监测视神经损害及指导青光眼的治疗提供了新的思路。我们主要阐述该技术在青光眼早期诊断中的应用。     

病理性近视视盘及其相关结构的形态学改变

病理性近视眼的视盘及其相关结构的形态学改变,包括视网膜神经纤维层厚度改变、视盘形态改变等,由此可引起相应的视功能改变.病理性近视眼因后巩膜葡萄肿的形成及生物力学特性的改变,可能导致视神经的结构和功能发生异常.这其中一些变化可能与青光眼的发生密切相关,或者对青光眼诊断造成困扰.     

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.     

HRT在青光眼与近视眼中的研究

青光眼是以进行性视神经损害为特征的不可逆性致盲眼病,其病理基础是视网膜神经节细胞及其纤维的进行性丧失;近视眼是开角型青光眼的易患因素,合并近视的青光眼患者其检查结果又有自身的特点,这给我们早期的准确诊断增加了难度;HRT是一种自动化的电子计算机控制的共焦激光眼底断层扫描仪。利用HRT(heidelberg retinatom ograph)可以获取视盘的三维地形图,通过对图像的分析处理,得到视盘和视网膜神经纤维层厚度的定量描述,并且可用于地形图变化的定量分析。本文就HRT在青光眼和近视眼特别是近视合并青光眼中的诊断和在视神经损害监测中的研究作一综述。     

原发性闭角型青光眼视神经盘结构和视野的改变

原发性闭角型青光眼已成为不可逆性致盲的最常见病因之一。对原发性闭角型青光眼的研究,除了关注眼前节,特别是房角的情况外,也有必要对其视神经损害模式进行研究。本文通过文献回顾,总结了原发性闭角型青光眼特别是急性闭角型青光眼眼底形态和视功能的改变,希望能更好地了解早期原发性闭角型青光眼的疾病特征,为临床治疗和研究提供帮助。     

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.     

Retinal nerve fiber layer analysis in the diagnosis of glaucoma

PURPOSE OF REVIEW: The detection of optic disc and retinal nerve fiber layer damage and change is the cornerstone of glaucoma management. Assessment of the retinal nerve fiber layer for localized and diffuse damage has been traditionally based on clinical examination, with documentation of change primarily qualitative. With the latest improvements in optical imaging instruments, objective and quantitative measurements of the retinal nerve fiber layer are now possible. This review summarizes the results from recent cross-sectional studies evaluating the discriminating ability of automated retinal nerve fiber layer measurements to detect glaucoma, and from longitudinal studies assessing the ability to predict and monitor glaucomatous changes. RECENT FINDINGS: Numerous cross-sectional studies have documented good diagnostic accuracy of a scanning laser polarimeter (GDx VCC), the optical coherence tomograph (Stratus), and the Heidelberg Retina Tomograph retinal nerve fiber layer measurements for differentiating between healthy and glaucoma eyes. There are only limited data available on the ability of these retinal nerve fiber layer measurements to document change over time. SUMMARY: It is essential that the clinician understand the specific strengths and weaknesses of each technique so that only good quality retinal nerve fiber layer information will be used in conjunction with careful clinical examination and visual function testing for glaucoma management decisions. Longitudinal studies are needed to evaluate the ability of these instruments to document retinal nerve fiber layer change over time.     

Optic disk evaluation and utility of high-tech devices in the assessment of glaucoma.

BACKGROUND: Every clinician has at one time or another examined a patient who was misdiagnosed as having glaucoma or whose diagnosis of glaucoma was missed. Although glaucoma can exist with normal intraocular pressures, clinicians often rely on the presence of visual-field defects and the degree of optic disk cupping to direct care. However, assessment of cupping is but one small part of optic disk evaluation in glaucoma, and other features of the optic nerve head and retinal nerve fiber layer must be closely inspected to help diagnose borderline cases. In addition, glaucoma can exist without visual-field loss. High-tech devices offer an added dimension in the objective assessment of structure when subjective tests of function and/or ophthalmoscopic observations are equivocal. METHODS: This article details the various parameters of optic disk and retinal nerve fiber layer evaluation and their significance in the assessment of glaucoma. In addition, the role of four high-tech devices is evaluated for their utility in the assessment and progression of glaucomatous damage. CONCLUSIONS: When one attempts to classify a patient as having glaucoma, the degree of cupping and the presence or absence of visual field loss can be misleading. Prior to definitive diagnosis, a thorough evaluation of the optic disk and retinal nerve fiber layer, and appropriate use of high-tech devices, should help reduce the under-diagnosis and overdiagnosis of this disease.     

Imaging of the optic nerve and retinal nerve fiber layer: An essential part of glaucoma diagnosis and monitoring

Because glaucomatous damage is irreversible early detection of structural changes in the optic nerve head and retinal nerve fiber layer is imperative for timely diagnosis of glaucoma and monitoring of its progression. Significant improvements in ocular imaging have been made in recent years. Imaging techniques such as optical coherence tomography, scanning laser polarimetry and confocal scanning laser ophthalmoscopy rely on different properties of light to provide objective structural assessment of the optic nerve head, retinal nerve fiber layer and macula. In this review, we discuss the capabilities of these imaging modalities pertinent for diagnosis of glaucoma and detection of progressive glaucomatous damage and provide a review of the current knowledge on the clinical performance of these technologies.     

原发性开角型青光眼的中医分型与RNFL厚度改变及视野损害关系

目的:探讨原发性开角型青光眼(青风内障)中医辨证分型与视网膜神经纤维层厚度的改变及视野损害之间关系的临床研究。方法:对72例144眼原发性开角型青光眼患者,采用光学相干断层成像术对144眼作围绕视盘3.4mm的环形扫描,记录各个象限视网膜神经纤维层厚度,并采用进口Humphry视野分析仪作中30°全定量视野检测检查,同时根据中医理论对患者作中医辨证分型,观察二者之间的关系。结果:中医的证型与视网膜神经纤维层厚度改变类型有统计学意义,中医证型与视野损害的类型有统计学意义(P<0.05)。结论:视神经损害较严重多见于青风内障的虚证,视神经损害早期多见于实证,因此视神经损害的程度在一定的程度上给予中医辨证治疗一定的指导作用。     

OCT测量视网膜神经纤维层厚度在青光眼诊断中的研究进展

青光眼是一种进展性视神经疾病,它能引起视神经结构改变,最终导致不可逆视功能损害。青光眼的早期诊断对保护视功能有重要的意义。光学相关断层扫描仪可以定量检测视网膜神经纤维层厚度,为早期诊断青光眼,监测视神经损害及指导青光眼的治疗提供了新的思路。本文主要反映该技术在青光眼诊断中的研究进展。许多研究都发现光学相关断层扫描仪检测的视网膜神经纤维层厚度在有视野改变的青光眼中有明显改变,且与视野损害在位置和严重程度上有很好的相关性,但仍缺乏有力的纵向研究来评价其在无视野改变青光眼中的诊断价值。     

Optic disc area in different types of glaucoma

AIM: To evaluate the possible relationship of optic disc area with retina nerve fiber layer in different glaucoma subtypes. METHODS: One eye each was chosen from 45 patients with ocular hypertension, 45 patients with primary open angle glaucoma, 45 patients with pseudoexfoliation glaucoma and 45 healthy controls followed in our hospital. The records of the patients were reviewed retrospectively. Optic disc area and circumpapillary retina nerve fiber layer measurements were obtained using optical coherence tomography. Central corneal thickness was measured by ultrasound pachymetry. RESULTS: The median disc area in the patients with primary open angle glaucoma was significantly higher than the patients with ocular hypertension (2.19 vs 1.90 mm2, P=0.030). The median retina nerve fiber layer was thinner in the patients with primary open angle glaucoma and pseudoexfoliation glaucoma than the patients with ocular hypertension for superior, inferior and temporal quadrants. After adjustment for age, no difference in central corneal thickness was found between the groups. Greater disc area was associated with thicker retinal nerve fiber layer for superior, inferior and nasal quadrants in the patients with primary open angle glaucoma. There was no correlation between disc area and central corneal thickness measurements of the groups. CONCLUSION: Disc size affects the retinal nerve fiber layer thickness in eyes with primary open angle glaucoma and is a possible risk factor for glaucomatous optic nerve damage.     

视盘出血在正常眼压青光眼中的形态学分析

目的 对正常眼压性青光眼（NTG）患者，前瞻性评估视盘出血和视网膜神经纤维层缺损及盘周萎缩弧之间的形态学关系。 方法 患者行每月1次眼底照相，眼底立体照相和计算机图像分析系统定性及定量评估视盘出血与神经纤维层缺损及萎缩弧的关系。 结果 NTG出血组37位患者42只眼有50处眼底视盘出血，出血眼中有35只有神经纤维层缺损，发生率83.3%（35/42）。非出血组35位患者40只眼中神经纤维层局限缺损为21个，发生率52.5%（21/40），两组间神经纤维缺损发生率无统计学意义（χ2=1.403, P=0.236，P＞0.05）。出血组和非出血组两组间β区萎缩弧的发生率差异有统计学意义（χ2=7.008, P=0.008，P＜0.01)，出血组β区萎缩弧面积(2.05±0.88) mm2，非出血组β区面积(1.42±0.53) mm2，两组比较有统计学意义（t=-2.785, P=0.008）。β区萎缩弧范围在出血组：(164.00±49.87)°，非出血组(128.42±40.04)°，两组间比较有统计学意义（t=-2.618, P=0.012，P＜0.05)。随诊中出血组和非出血组盘沿丢失发生率组间比较有统计学意义（χ2=5.802, P=0.016，P＜0.01），但组间比较随诊视野损害的发生率则无统计学意义。 结论 NTG中视盘出血和神经纤维层缺损及萎缩弧之间有密切的关系。随诊中发现出血组较非出血组有更多的盘沿丢失和萎缩弧面积改变，提示NTG视盘出血是疾病进展的危险因素。 (中华眼底病杂志, 2006, 22: 232-235)     

New findings in the evaluation of the optic disc in glaucoma diagnosis

PURPOSE OF REVIEW: Ophthalmoscopical evaluation of the optic disc is a feasible and largely accessible method to diagnose glaucoma. Many qualitative parameters have been described in glaucomatous optic neuropathy. Considering individual variations in the details of topography or tissue components damaged by the glaucomatous process, however, adequate identification of glaucomatous optic disc signs requires training and experience. Without adequate guidelines of optic disc examination, the physician may miss important aspects that could lead to adequate diagnosis or identification of progression in a patient with established glaucoma. This paper presents a systematic approach for the examination of the optic disc and retinal nerve fiber layer to aid the detection of glaucoma. RECENT FINDINGS: Optic disc qualitative parameters are better than quantitative parameters in separating glaucomatous from normal eyes. The sequential evaluation of optic disc size, neuroretinal rim size and shape, retinal nerve fiber layer, presence of peripapillary atrophy, and presence of retinal or optic disc hemorrhages enhances the ability to detect glaucomatous damage and its progression. SUMMARY: Ophthalmologists should be familiar with glaucomatous optic disc signs that can be identified during clinical examination. A simple systematic approach may allow improved diagnosis and management of glaucoma.