视网膜神经纤维层定量测定在青光眼方面的应用

Quantitative Retinal Nerve Fiber Layer Measurement in Glaucoma

青光眼的主要病理过程是视网膜节细胞轴突（即视神经纤维）的丢失，故测量视网膜神经纤维层（ｒｅｔｉｎａｌｎｅｒｖｅｆｉｂｅｒｌａｙｅｒ，ＲＮＦＬ）来确定轴突丢失的程度在青光眼的早期诊断和治疗上具有非常重要的意义。近年来，计算机图像分析技术应用于眼科，它能对ＲＮＦＬ作出客观的量化检测。该文综述有关文献，就ＲＮＦＬ定量测定方法的原理，以及它们在青光眼ＲＮＦＬ损害检测方面的应用情况作一介绍。

Axon loss of the retinal nerve ganglion cells is the main defect in glaucoma. Early detection and prevention of glaucomatous damage is of vital importance,because glaucomatous injury is largely irreversible. Examination of the peripapillary nerve fiber layer is considered essential in both detecting and monitoring glaucoma. Recently computerized image analysis techniques were developed for quantitative and objective measurements of the retinal nerve fiber layer(RNFL).These techniques, such as Nerve Fiber Analyzer(NFA) and Optical Coherence Tomography, were developed to measure thickness of RNFL. The physical principles underlying these two approaches were reviewed in this paper. Two other techniques, Rodenstock Analyzer and Herdeberg Retina Tomography(HRT),may be also used as powerful tools in the early diagnosis and follow up of glaucoma. These methods were applied to healthy subjects,patients with ocular hypertension,and patients with glaucoma at various degree of progression of the disease. They can provide quantitative measurements that correspond to known properties of the RNFL in normal and glaucomatous eyes. Studies showed the RNFL, especially in the inferior and superior regions, was significantly thinner in glaucomatous eyes than in normal eyes.As reported by Weinreb and associates, the correlation (R=0.83)between retardation and the histopathologic measurement of RNFL thickness was excellent. These techniques can be used to evaluate the association between quantitative RNFL measurements and visual field loss in patients with primary open angle glaucoma.Quantitative measures of the RNFL using both HRT and NFA were correlated with visual field loss in glaucoma patients.In patients with established glaucoma ,sensitive measurements of progression will help to guide medical and surgical treatment.Caprioli and associate reported quantitative method of RNFL is valuable way to detect structural change in early glaucoma.Sagono and associates found RNFL height changes which might occur after trabeculectomy were pressure dependent. In conclusion:quantitative methods of RNFL evaluation do provide the potential solution to the need for a sophisticated means of documenting the presence and progression of glaucomatous damage.