Optic disc morphology in pigmentary glaucoma

AIM—To evaluate the morphology of the optic nerve head in eyes with pigmentary glaucoma.
METHODS—Colour stereo optic disc photographs of 62 patients with pigmentary glaucoma and 566 patients with primary open angle glaucoma were morphometrically evaluated. By prestudy selection, mean visual field defect and neuroretinal rim area were not significantly different between the two groups (p=0.89 and p=0.45).
RESULTS—The pigmentary glaucoma group did not vary significantly (p >0.10) from the primary open angle glaucoma group in size and shape of the optic disc, configuration of neuroretinal rim, depth of optic cup, area of alpha zone of parapapillary atrophy, diameter of retinal vessels at the disc border, and frequency of disc haemorrhages and localised retinal nerve fibre layer defects. The beta zone of parapapillary atrophy was slightly, but not statistically significantly (p=0.06), smaller in the pigmentary glaucoma group. The mean maximal intraocular pressure and mean intraocular pressure amplitude were significantly (p<0.001) higher in the pigmentary glaucoma group.
CONCLUSIONS—In contrast with the characteristic morphology of the anterior segment and despite significantly higher intraocular pressure peaks and a larger pressure amplitude, eyes with pigmentary glaucoma compared with eyes with primary open angle glaucoma do not show a pathognomonic morphology of the optic disc and retinal nerve fibre layer. The slightly smaller beta zone of parapapillary atrophy may correspond to higher intraocular pressure in pigmentary glaucoma.

Keywords: optic disc morphology; pigmentary glaucoma; secondary open angle glaucoma     

Laser scanning tomography of localised nerve fibre layer defects

AIMS—Retinal nerve fibre layer photography is a well established method to qualitatively document early structural changes which might be induced by primary open angle glaucoma. The aim was to analyse localised retinal nerve fibre layer (RNFL) defects in a new quantitative way with respect to surface topography, defect width, and surface reflectivity by means of the technique of confocal scanning laser tomography.
METHODS—12 eyes of 12 patients with a localised RNFL defect documented in RNFL photographs and a normal appearance of the optic disc were enrolled in the study. Using confocal laser scanning tomography (Heidelberg retina tomograph, HRT) a series of 32 optical section images from different focal planes of the retina at the site of the RNFL defects were obtained. The optical section images, the reflectivity images, and the topographic images were analysed regarding the visibility of the RNFL defects. The mean surface height and the reflectance at the sites of the RNFL damage were measured and compared with the adjacent apparently normal retina. The width of the RNFL defect at 1 mm distance from the disc border was evaluated.
RESULTS—RNFL defects could be detected in nine of 12 reflectivity images (75%). Single optical section images displayed the RNFL defects in 12 of 12 eyes. The defect width ranged from 0.11 to 1.0 mm. In six of 12 eyes a surface depression (34 (SD 5) µm; range 21-47 µm) was present. The reflectance ratio ranged from 0.68 to 0.94 at the site of the RNFL defect. In eyes with a glaucomatous scotoma in a 6° grid visual field (VF), the defect width was at least 0.25 mm. Surface depression and low reflectance ratio were found irrespective of the presence of a scotoma in the 6° grid VF.
CONCLUSION—The majority of localised RNFL defects can be detected in reflectivity images from laser scanning tomograms. Localised RNFL defects may be differentiated according to surface topography into those with and those without a measurable surface depression. A small but deep RNFL defect is not necessarily associated with a scotoma in routine 6° grid VF static perimetry.

Keywords: primary open angle glaucoma; nerve fibre layer defects; laser scanning tomography; Heidelberg retina tomograph     

OCT快速和重复扫描法在青光眼诊断中的可重复性研究

目的：评价应用光学相干断层成像术(OCT)快速和重复法测量视网膜神经纤维层(retinal nerve fiber layer,RNFL)厚度在诊断青光眼中的可重复性意义。

方法：应用Stratus OCT测量38例正常人和42例原发性开角型青光眼患者的RNFL厚度,分别应用快速和重复扫描两种方案来测量正常人和原发性开角型青光眼患者RNFL厚度,通过统计各组视盘区域中颞区、上区、下区和鼻区共四个象限的总体平均RNFL厚度的组内相关系数和变异性系数来进行重复性评估。

结果：在正常人和原发性开角型青光眼患者中,总体平均RNFL厚度和颞侧、上方、鼻侧、下方RNFL厚度,两组均未显示出差异; 而重复扫描方案较之快速扫描在视盘周围测出的平均RNFL厚度具有更高的ICC和更低的CV值,在颞区存在统计学差异(P=0.042),在颞区、鼻区、上区和下区中得出的RNFL厚度的ICC(CV值)如下：快速扫描分别为0.918(7.2%),0.831(6.82%),0.856(5.12%),0.911(7.19%); 而重复扫描的分别为0.927(3.21%),0.962(5.01%),0.909(6.02)%,0.869(4.67%),0.918(6.89%)。

结论：OCT测量RNFL厚度中应用快速和重复扫描在正常人和原发性开角型青光眼中均具有可重复性的价值,而重复扫描方案在评估RNFL厚度方面更为精确。     

Effect of retinal nerve fibre loss on the optic nerve head configuration in early glaucoma

Twenty-nine ocular hypertensive patients with an optic disc haemorrhage, normal optic discs and normal visual fields were followed in this partly retrospective study by means of sequential optic disc stereophotographs and retinal nerve fibre layer (RNFL) photographs for a period of up to 14 years (mean 5.2). During this time early structural glaucoma damage developed in 11 patients (12 eyes). RNFL photographs revealed a nerve fibre loss in 10 of the 12 cases (83%). However, even accurate cup to disc ratio measurements from disc stereophotographs enlarged 20 times showed a measurable increase of horizontal and vertical cup to disc ratios in only 33% and 42% of the pathological cases, respectively. This result indicates that haemorrhage-associated RNFL defects precede measurable changes of the optic disc configuration. Therefore, RNFL photography seems to be a useful and sensitive examination method for the detection of the earliest organic damage in glaucoma.     

Localised retinal nerve fibre layer defects in chronic experimental high pressure glaucoma in rhesus monkeys

AIM: To evaluate prospectively in an experimental model of chronic high pressure glaucoma whether the concept of a mainly diffuse pattern of optic nerve damage holds true for high pressure glaucoma. METHODS: The study comprised nine eyes of nine rhesus monkeys (Macaca mulatta) with a mean age of 17.7 (SD 3.1) years (range 13-23 years). Experimental glaucoma was produced by multiple applications of argon laser to the trabecular meshwork. Applanation tonometry was regularly performed and fundus photographs, which were taken serially, were used for retinal nerve fibre layer (RNFL) assessment and morphometric optic disc analysis. Six monkeys, in which arterial hypertension and atherosclerosis had additionally been induced several years before elevation of intraocular pressure, did not show any sign of diffuse loss or localised defects of the RNFL before initiation of glaucoma. RESULTS: Compared with the same eyes at baseline, localised RNFL defects had developed in eight (89%) eyes. It included all three eyes (100%) of the monkeys without arterial hypertension/arteriosclerosis, and five of the six monkeys (83%) with arterial hypertension/arteriosclerosis. Four eyes had multiple localised RNFL defects. In all eyes, diffuse RNFL loss was additionally present. CONCLUSIONS: Besides diffuse loss of RNFL, localised RNFL defects were present in almost all eyes of monkeys with chronic experimental high pressure glaucoma. Challenging the concept that a mostly diffuse type of optic neuropathy occurs in high pressure glaucoma, the results suggest that, in high pressure glaucoma, at least a mixture of localised and diffuse pattern of optic nerve damage prevails.     

Comparison of algorithms for detection of localised nerve fibre layer defects using scanning laser polarimetry

AIMS: To evaluate different algorithms used to analyse retinal nerve fibre layer thickness (RNFL) data obtained by scanning laser polarimetry, in order to compare their relative abilities to discriminate between patients with glaucomatous localised nerve fibre layer defects and normal subjects. METHODS: 48 eyes of 48 glaucomatous patients with localised RNFL defects and 53 eyes of 53 healthy subjects were included in this study. The localised RNFL defects were identified by RNFL photography and/or slit lamp biomicroscopic examination. All patients were submitted to RNFL examination using scanning laser polarimetry (GDx nerve fibre analyser, Laser Diagnostic Technologies, Inc, San Diego, CA, USA). Three methods of analysis of polarimetry data were used: GDx software provided parameters; RNFL thickness measurements in 16 equal sectors around the optic disc (sectoral analysis); and Fourier analysis of the curve of distribution of RNFL thickness measurements. Linear discriminant functions were developed to assess sensitivity and specificity of the sectoral based analysis and Fourier analysis and were compared to the GDx parameters. In addition, areas under the receiver operating characteristic (ROC) curves were compared. RESULTS: At a fixed specificity of 91%, the sensitivity of the linear discriminant function from sectoral data (LDF sectoral) was 81%, with an area under the ROC curve of 0.93. The linear discriminant function from Fourier measures had a comparable performance, with an area under the ROC curve of 0.93, and sensitivity of 71% for specificity at 91%. At the same specificity, the sensitivities of the GDx software provided parameters ranged from 15% to 40%. The areas under the ROC curves for the LDF sectoral and LDF Fourier were significantly greater than the ROC curve area for the single best GDx parameter. CONCLUSION: The sectoral based analysis and the Fourier analysis of RNFL polarimetry data resulted in an improved detection of eyes with glaucomatous localised nerve fibre layer defects compared to the GDx software provided parameters.     

Specificity and sensitivity of glaucoma detection in the Japanese population using scanning laser polarimetry.

AIMS: To investigate the usefulness of the scanning laser polarimeter (GDx; GDx Nerve Fiber Analyzer) for glaucoma detection in the Japanese population, and to investigate the difference in the thickness of retinal nerve fibre layer (RNFL) between normal tension glaucoma (NTG) and primary open angle glaucoma (POAG). METHODS: 69 eyes of 69 normal subjects and 115 eyes of 115 chronic open angle glaucoma patients (60 NTG and 55 POAG patients) were studied. The thickness of RNFL was measured with GDx. An eye was diagnosed as glaucomatous, if at least one original GDx variable showed p <5%. The difference in thickness of RNFL between the NTG and POAG groups was then investigated. RESULTS: 46 normal eyes (66.7%) were diagnosed as not glaucomatous (no variables showing p <5%), and 93 glaucomatous eyes (46 NTG and 47 POAG eyes) (80.9%) were diagnosed as glaucomatous. Actual values of average thickness, ellipse average, superior average, and superior integral were significantly lower in the POAG group than those in the NTG group. CONCLUSIONS: New variables which elucidate focal RNFL defects or early changes are needed to improve the moderate detection ability found in this present study. The pattern of the change in RNFL may differ in NTG and POAG groups.     

Period prevalence and incidence of optic disc haemorrhage in normal tension glaucoma and primary open-angle glaucoma

Background: To investigate and compare the period prevalences and incidences of optic disc haemorrhages in normal tension glaucoma and primary open‐angle glaucoma. Design: Hospital‐based retrospective study. Participants: Four hundred and four patients with normal tension glaucoma and 210 patients with primary open‐angle glaucoma that underwent consecutive disc examinations at least quarterly for at least 1 year and stereoscopic optic disc photographs at intervals of 6 to 12 months between 1992 and 2007. Methods: The period prevalence of disc haemorrhages, gender predominance among patients with disc haemorrhage, and cumulative incidence of normal tension glaucoma and primary open‐angle glaucoma were compared. Main Outcome Measures: Period prevalence, cumulative incidence, and gender predominance of DHs in patients with NTG and POAG. Results: Three hundred and eighty‐seven patients (387 eyes) of normal tension glaucoma patients and 205 patients (205 eyes) of primary open‐angle glaucoma patients were finally enrolled in the study. The period prevalence and incidence rates of the stereoscopic optic disc photograph‐confirmed glaucomatous disc haemorrhages were 33.3% (129/387), 0.46 ± 0.18 times/year in the normal tension glaucoma group, and 17.6% (36/205), 0.34 ± 0.23 times/year in the primary open‐angle glaucoma group, respectively. The absolute values and ratios of primary open‐angle glaucoma and normal tension glaucoma in period prevalences and incidence rates in the present study were higher than in previous studies. No significant difference in gender ratios was found between patients that did or did not develop disc haemorrhage for both types of open‐angle glaucoma (P > 0.05, respectively). Conclusions: The primary open‐angle glaucoma group had higher period prevalences and incidence rates of disc haemorrhage than those reported previously. Disc haemorrhages were found to develop independent of gender.     

高眼压性和正常眼压性原发性开角型青光眼视神经损害特征的比较

目的探讨高眼压性原发性开角型青光眼(POAG)和正常眼压性青光眼(NTG)患者视神经损害的不同特点。方法应用德国Heidelberg公司生产的视网膜断层扫描仪对高眼压性POAG39例(47只眼)和NTG32例(38只眼)进行定量视盘参数和神经纤维层检查,并行眼底立体照相观察视网膜神经纤维层(RNFL)缺损类型,检测静态定量视野,并对检查结果进行比较。结果(1)NTG组视盘总体参数和分区(除颞侧外)盘沿面积、沿/盘面积小于高眼压性POAG组,而C/D大于高眼压性POAG组;平均RNFL厚度和RNFL面积在颞下和颞上小于高眼压性POAG组;总体盘沿容积小于高眼压性POAG组,总体平均视杯深度和颞下视杯面积大于高眼压性POAG组,两组差异均有统计学意义(P<005)。两组颞侧视盘各参数比较,差异无统计学意义(P>005)。(2)RNFL缺损类型高眼压性POAG组RNFL弥漫性缺损占5319%,局限性缺损占426%;NTG组弥漫性缺损占2105%,局限性缺损占5526%。两组RNFL缺损类型构成比比较,差异有统计学意义(P<001)。结论NTG较高眼压性POAG具有较大的C/D值、C/D面积比和窄盘沿面积,RNFL丢失严重。高眼压性POAG患者的RNFL以弥漫性缺损为主,NTG患者的RNFL以局限性缺损为主。两者视神经损害具有不同特点,其损害机制可能不同。(中华眼科杂志,2005,41136140)     

Comparison of localised nerve fibre layer defects in normal tension glaucoma and primary open angle glaucoma

AIM: To compare the pattern of localised nerve fibre layer (NFL) defects in normal tension glaucoma (NTG) and primary open angle glaucoma (POAG). METHODS: 50 NTG eyes and 36 POAG eyes, all with localised NFL defects, were enrolled. On retinal NFL photography, the proximity of the defect to the centre of the fovea (angle alpha) and the sum of the angular width of the defects (angle beta) were determined. Angle alpha was the angle made by a line from the centre of the fovea to the disc centre and a line from the disc centre to the disc margin, where the nearest border of the defect met. The patterns of localised NFL defects in NTG and POAG were compared with angles alpha and beta. Independent t test was used for statistical analysis. RESULTS: Angle alpha in NTG (35.1 (SD 20.0) degrees ) was significantly smaller than that of POAG (45.9 (21.9) degrees ) (p=0.02), while angle beta in NTG (49.0 (31.9) degrees ) was significantly larger than that of POAG (33.1 (23.9) degrees ) (p=0.01). CONCLUSIONS: The pattern of NFL defects in NTG was different from that in POAG. Localised NFL defects in NTG were closer to the fovea and wider in width than those in POAG.     

Optic disc haemorrhages and vascular abnormalities in a glaucoma population

Purpose: To retrospectively examine the optic disc photographs of a glaucoma population for optic disc haemorrhages, vascular occlusions and vascular abnormalities. Methods: The optic disc photographs of 906 eyes of glaucoma and suspect glaucoma patients were examined. Optic disc photographs were taken annually, where possible, with the follow-up period varying between 1 and 14 years duration (mean, 2.89). Glaucoma patients are regularly reviewed every 4–6 months and glaucoma suspects every 1–2 years, depending on the ophthalmologist. Low-tension glaucoma patients were reviewed more frequently (mean, every 2.6 months). The results of the findings were compared to a control group of 39 subjects with a mean follow-up period of 7 years, using Fisher's exact test. Results: It was found that during the period under review, 7.4% (n= 67) of eyes had optic disc haemorrhages. The highest frequency of optic disc haemorrhages (37.5%) was found in the low tension glaucoma group (P= 0.0001) followed by 11.4% of primary open-angle glaucoma eyes (P= 0.03). In the normal group there were three eyes with optic disc haemorrhages and one with a disc collateral, which constitutes 5.1% vascular changes in this sub-group. Of the study eyes 2.8% had central retinal vein occlusions, 1.3% branch vein occlusion, 1.2% disc vessel abnormalities (loops) and 1.1% disc collaterals. Discrete nerve fibre layer haemorrhages and microaneurysms were found in 0.8% and 1.8% of eyes, respectively. Conclusions: A total of 16.8% of the eyes observed in this study had either disc haemorrhages or vascular changes. The underlying trend of vascular and haemorrhagic changes in glaucoma are demonstrated in this sample, which is in general agreement with previous studies. The high percentage of optic disc haemorrhages in low tension glaucoma is highlighted. The presence of microaneurysms and nerve fibre layer haemorrhages is interesting but of unknown significance.     

Polarimetric measurement of retinal nerve fiber layer thickness in glaucoma diagnosis

PURPOSE: To evaluate reliability and diagnostic value of polarimetric measurements of the retinal nerve fiber layer (RNFL) thickness in the diagnosis of glaucoma. METHODS: The study included 81 eyes with perimetric glaucoma with glaucomatous changes of the optic disc and visual field defects; 52 eyes with preperimetric glaucoma with glaucomatous optic disc abnormalities and normal achromatic visual fields; and 70 normal eyes. For determination of reliability, four examiners repeated polarimetric measurements five times in ten normal subjects. RESULTS: The polarimetric variables were significantly correlated with increasing mean visual field defect and decreasing neuroretinal rim area. In correlation analyses with visual field defects, correlation coefficients were highest for the variable "superior/nasal ratio" and "the Number," a variable calculated by the neural network of the device. In correlations with neuroretinal rim area, correlation coefficients were highest for measurements of the inferior nerve fiber layer thickness. The preperimetric glaucoma group and the control group differed significantly in the variables "superior/nasal ratio" and "the Number" and, to a smaller degree, in the variables "superior/temporal ratio" and "superior/inferior ratio." The Number variable had a sensitivity of 82% and 58% at a predefined specificity of 80% in separating perimetric glaucoma patients and preperimetric glaucoma patients, respectively, from control subjects. Reproducibility of the polarimetric measurements ranged between 70% and 89%. CONCLUSION: Polarimetric measurements of the RNFL thickness can detect glaucomatous optic nerve damage in patients with visual field loss, and in some patients with preperimetric glaucomatous optic nerve damage. Considering the fast performance, easy handling, and low maintenance costs, RNFL polarimetry may be helpful in glaucoma diagnosis.     

原发性开角型及慢性闭角型青光眼患者视盘毛细血管密度和视野缺损的关联性研究

目的 本研究旨在通过分析原发性开角型青光眼(POAG)患者和慢性原发性闭角型青光眼(PACG)患者的视盘毛细血管密度与视野缺损的相关性,探讨视盘毛细血管密度在青光眼诊断和病情评估中的价值。方法 纳入2017年9月2018年9月我院收治的POAG患者90例(90眼)作为POAG组,慢性PACG患者75例(75眼)作为PACG组,2组的年龄、性别和视野平均缺损(MD)值进行了匹配。此外,纳入同期性别、年龄匹配的60位健康体检者60眼作为对照组。检测所有参与者的视盘毛细血管密度、视网膜神经纤维层(RNFL)厚度及视野缺损情况。结果 POAG和PACG患者的平均RNFL厚度和平均毛细血管密度均显著低于正常人(P<0.05),而POAG患者和PACG患者的平均RNFL厚度和平均毛细血管密度差异没有统计学意义(P>0.05)。对于POAG患者,其视盘上方、下方、颞侧和全区的RNFL厚度与视野MD值呈负相关(r=-0.525,-0.462,-0.246,-0.453,P均<0.05),但是鼻侧的RNFL厚度与视野MD值无相关性(r=-0.198,P>0.05)。4个区域和全区的毛细血管密度与视野MD值均呈显著负相关(r=-0.341,-0.426,-0.285,-0.298,-0.557,P均<0.05)。对于PACG患者,仅上方、下方和全区的RNFL厚度与视野MD值相关(r=-0.543,-0.604,-0.448,P均<0.05),但是4个区域及全区的毛细血管密度均与视野MD值显著相关(r=-0.613,-0.494,-0.179,-0.413,-0.589,P均<0.05)。结论 视盘毛细血管密度与POAG和PACG患者的视野缺损相关,视盘毛细血管密度的变化对于青光眼的诊断和病情评估有重要的参考价值。     

The retinal nerve fiber layer in normal eyes and in glaucoma. I. Semiquantitative data of 398 eyes with glaucoma

Atrophy of the optic nerve is associated with changes of the retinal fiber layer (RNFL). Using red-free photographs the authors examined the RNFL of 398 eyes with chronic primary open-angle glaucoma and compared it with the RNFL of 234 normal eyes. The glaucoma group was divided into five stages and the fundus into four sectors. Differences between the normal and glaucoma eyes were: (1) The sequence of the sectors, with regard to the best visibility of the retinal nerve fiber bundles, was changed. In the normal eyes the nerve fiber bundles were most often best visible in the inferior temporal sector, followed by the superior temporal sector, the temporal horizontal area and finally the nasal region. In the glaucoma group the nerve fiber bundles were significantly more often best detectable in the superior temporal sector and the temporal horizontal area. (2) The degree of visibility of the retinal nerve fibers decreased significantly with increasing glaucoma stage. (3) Localized defects were seen in 15% of the eyes with glaucoma and none of the normal eyes. The specificity of this qualitative parameter was, therefore, 100%. The defects were found most often in the superior and inferior temporal regions. These differences between normal and glaucomatous eyes were also significant for the first glaucoma stage of this study. The localization of the foveola below the optic disk center (0.53 +/- 0.34 mm in the glaucoma group and 0.55 +/- 0.29 mm in the normal eyes) was not significantly different.     

频域光学相干断层扫描（OCT）测量视盘参数及视网膜厚度在早期青光眼诊断中的作用

目的　探讨频域光学相干断层扫描（optical coherence tomography,OCT）测量视盘参数及视网膜厚度在早期青光眼诊断中的作用。方法　采用频域OCT测量40例（40眼）健康志愿者（对照组）和85例（85眼）原发性开角型青光眼（primary open angle glaucoma,POAG）患者［早期青光眼亚组（n=36）和进展期青光眼亚组（n=49）］视盘参数及视网膜神经纤维层（retinal nerve fiber layer,RNFL）厚度,比较各组RNFL厚度、视盘参数并与视野平均缺损（mean deviation,MD）值进行相关性分析,采用ROC曲线下面积评估视盘周围区RNFL厚度及视盘参数在青光眼中的诊断效果。结果　POAG组患者颞侧、上方、鼻侧及下方象限RNFL厚度和全周RNFL厚度均显著低于对照组（均为P<0.05）,且与早期青光眼组比较,进展期青光眼组患者颞侧、上方、鼻侧及下方象限RNFL厚度和全周RNFL厚度均显著降低（均为P<0.05）。各组除视盘面积外,其他视盘参数比较差异均具有统计学意义（均为P<0.05）。Pearson相关性分析显示,POAG组患者视盘颞侧、上方、下方象限RNFL厚度及全周RNFL厚度与MD均呈负相关（均为P<0.05）,而视盘参数中视杯容积和视杯/视盘面积比与MD均呈正相关（均为 P<0.05）,盘缘面积、盘缘容积和视盘容积与MD均呈负相关（均为P<0.05）。经ROC曲线分析显示,视盘周围区下方象限RNFL厚度的曲线下面积最大为0.886,其特异度和敏感度分别为0.775和0.924;视盘参数中视杯/视盘面积比曲线下面积最大,其特异度和敏感度分别为0.741和0.815。结论　OCT检测视盘结构和RNFL厚度能够用于青光眼早期诊断,且具有较高敏感度和特异度。     

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.     

早期青光眼不同类型视盘视网膜神经纤维层厚度分析

目的　探讨早期青光眼患者不同类型视盘的视网膜神经纤维层（ｒｅｔｉｎａｌｎｅｒｖｅｆｉｂｅｒｌａｙｅｒ,ＲＮＦＬ）厚度,以了解不同类型视盘的早期青光眼患者的ＲＮＦＬ厚度的特点。方法　应用光学相干断层扫描（ｏｐｔｉｃａｌｃｏｈｅｒｅｎｃｅｔｏｍｏｇｒａｐｈｙ,ＯＣＴ）技术检查视盘ＲＮ-ＦＬ厚度,将收集到的ＯＣＴ视盘检查结果分为６组:对照组大视盘组、中视盘组、小视盘组,每组各２０眼,早期青光眼大视盘组、中视盘组、小视盘组各２０眼。ＯＣＴ测量１２０眼各钟点平均ＲＮＦＬ厚度。检测对照组和早期青光眼患者１２个钟位的视盘ＲＮＦＬ厚度。结果　对照组不同类型视盘组的ＲＮＦＬ厚度曲线均在下方和上方形成双峰,在鼻侧和颞侧形成波谷,各组下方峰均高于上方峰。其中大视盘组患者ＲＮＦＬ厚度（１０５．６０±５．８７）μｍ,其次是中视盘组（１０７．０５±７．２９）μｍ和小视盘组（１０８．４０±７．２７）μｍ。对照组大、中、小视盘组的ＲＮＦＬ厚度差异无统计学意义（Ｐ＞０．０５）。早期青光眼ＲＮＦＬ厚度曲线的上或下方峰值降低,但仍然具备上、下方的双峰特征,各组的下方峰皆高于上方峰。其中大视盘组患者ＲＮＦＬ厚度最薄（７０．２５±１４．７１）μｍ,其次是中视盘组（８５. ５５±１５．３９）μｍ和小视盘组（８７．５５±９．４６）μｍ,大视盘组与中视盘组、小视盘组的视盘ＲＮＦＬ厚度的差异有统计学意义（均为Ｐ＜０．０５）,中视盘组与小视盘组的ＲＮＦＬ厚度差异无统计学意义（Ｐ＞０．０５）。早期青光眼患者与对照组不同类型视盘的ＲＮＦＬ均为厚度差异均有统计学意义（均为Ｐ＜０．０５）。结论　对照组不同大小的视盘并不影响ＲＮＦＬ厚度,早期青光眼患者视盘的ＲＮＦＬ厚度明显变薄,但仍然具备上、下方的双峰特征,各组的下方峰皆高于上方峰,其中大视盘患者的ＲＮＦＬ比中、小视盘受损更严重。     

亚在地区青光眼的流行病学

Primary open angle glaucoma is the second most important cause of permanent blindness in the Asia-Pacific region. Thus it is very important to identify epidemiological and other risk factors which are associated with open angle glaucoma. The risk for glaucoma optic nerve damage increases with the age and with the level of the intraocular pressure. In this paper, I will highlight our study of several risk factors for development of the open angle glaucoma like (1) elevated intraocular pressure, (2) myopia, (3) suspicious large optic disc cup, (4) cupping with disc haemorrhages and (5) nerve fibre defect. The general and systemic conditions which are implicated as risk factors are (1) family history of glaucoma. (2) increase in age, (3) diabetes mellitus, (4) cardiovascular conditions like central retinal vein occlusion etc. (5) the endocrine disorders with increased thyroid and increased corticosteroids responsiveness in patients with glaucoma will be discussed.     

Quantification of retinal nerve fiber thickness. A comparison of laser scanning ophthalmoscopy, polarimetry and optical coherence tomography in healthy and glaucomatous eyes

Purpose. To evaluate the thickness of the retinal nerve fiber layer (RNFL) in healthy eyes and in eyes of patients with primary open angle glaucoma using the Heidelberg retina tomograph (HRT), the nerve fibre analyser (NFA) and the optical coherence tomograph (OCT). Methods. In this prospective cohort study, 40 normal eyes and 86 eyes of age-matched glaucoma patients were compared by confocal scanning laser tomography using the HRT, scanning laser polarimetry (NFA) and optical coherence tomography (OCT). The RNFL thickness was measured in the superior, inferior, nasal and temporal regions as well as the total circumference. Results. All three methods revealed a statistically significant difference between normal and glaucomatous eyes with respect to the mean RNFL thickness in the inferior and superior regions (p<0.001). The mean RNFL thickness in the superior region was 329 μm (HRT), 87 μm (NFA) and 94 μm (OCT) in healthy volunteers compared to 275 μm (HRT), 72 μm (NFA) and 82 μm (OCT) in the patient group. In the inferior region, it was 323 μm (HRT), 87 μm (NFA) and 93 μm (OCT) in healthy subjects versus 240 μm (HRT), 74 μm (NFA) and 83 μm (OCT) in glaucoma patients. Cut-off points to differentiate between normal and glaucomatous eyes could not be defined. There was no difference in the RNFL thickness of right and left eyes. Conclusions. In RNFL thickness measurements using HRT, NFA and OCT, glaucoma patients showed a significantly thinner RNFL in the superior and inferior areas compared to healthy volunteers. These results confirm the known histological and fundus photographic findings of RNFL thinning near the optic disc in glaucoma patients. Although RNFL thickness cannot be used to diagnose glaucoma in individual patients due to the high interindividual differences, the quantitative assessment of RNFL thickness may complement the diagnostic armamentarium as a sensitive parameter for diagnosing and monitoring glaucomas.     

GDxVCC检测原发性开角型与可疑青光眼视网膜神经纤维层损害的对比研究

目的采用GDxVCC系统检测正常人、可疑开角型青光眼(suspected open angle glaucoma，SOAG)以及原发性开角型青光眼(primary open angle glaucoma，POAG)患者的视盘周围视网膜神经纤维层(retinal nerve fiber layer，RNFL)厚度，并进行对比分析，探讨GDxVCC系统在青光眼早期诊断中的价值。设计前瞻性对照研究。研究对象42例SOAG，36例POAG以及年龄相匹配的36例正常人参加此项研究。方法所有参加者进行视野与GDxVCC系统检查，选择一眼进行分析。采用方差分析，对SOAG、POAG、正常人的RNFL参数进行两两比较。主要指标GDxVCC检测RNFL厚度。结果POAG组与正常组问所有RNFL参数差异均有极显著意义(P=0．000)；POAG组与SOAG组间所有RNFL参数差异均有极显著意义(P=0．000)；SOAG组与正常组间椭圆平均值差异无统计学意义(P=0．234)，但其上方平均值与下方平均值及神经纤维指数差异均有统计学意义(P=0．044、P=0．045、P=0．035)，TSNIT标准差有极显著意义(P=0．000)。结论GDxVCC系统能更早地发现青光眼性RNFL结构损害，不仅可用于青光眼诊断和随访，亦可用于对可疑青光眼进行追踪。