Beta-zone parapapillary atrophy and multifocal visual evoked potentials in eyes with glaucomatous optic neuropathy

We investigated changes in multifocal visual evoked potential (mfVEP) responses due to beta-zone parapapillary atrophy (ßPPA). Patients with glaucomatous optic neuropathy (GON) with or without standard achromatic perimetry (SAP) abnormalities were referred for mfVEP testing during a 2-year period. Eyes with good quality optic disc stereophotographs and reliable SAP results were included. The mfVEP monocular mean latency delays (ms) and amplitudes (SNR) were analyzed. Age, SAP mean deviation (MD), pattern standard deviation (PSD), and spherical equivalent (SE) were analyzed in the multivariate model. Generalized estimated equations were used for comparisons between groups after adjusting for inter-eye associations. Of 394 eyes of 200 patients, 223 (57%) had ßPPA. The ßPPA eyes were older (59.6 ± 13.7 vs. 56.5 ± 13.7 year, P = 0.02), more myopic (?4.0 ± 3.5 vs. ?1.3 ± 3.5 D, P < 0.01), and had poorer SAP scores (MD: ?4.9 ± 5.2 vs. ?2.6 ± 5.2 dB, P < 0.01; PSD: 4.3 ± 2.9 vs. 2.5 ± 3.0 dB, P < 0.01). By univariate analysis, mean latencies were longer in ßPPA eyes (6.1 ± 5.3 vs. 4.0 ± 5.5 ms, P < 0.01). After adjusting for differences in SE, age, and SAP MD, there was no significant difference between the two groups (P = 0.09). ßPPA eyes had lower amplitude log SNR (0.49 ± 0.16 vs. 0.56 ± 0.15, P < 0.01), which lost significance (P = 0.51) after adjusting for MD and PSD. Although eyes with ßPPA had significantly lower amplitudes and prolonged latencies than eyes without ßPPA, these differences were attributable to differences in SAP severity, age, and refractive error. Thus, ßPPA does not appear to be an independent factor affecting mfVEP responses in eyes with GON.     

Discrimination between normal and glaucomatous eyes.

Discriminant analysis of quantifiable optic nerve, nerve fiber layer, and visual field measurements were used to assign eye to normal or glaucomatous groups. A database of 185 glaucoma patient with early visual field loss and 54 normal controls was used to develop and test the discriminant function. Parameters that discriminated best between normal and glaucoma were relative nerve fiber layer height and visual field mean defect. Cup-disc ratio, an estimate of optic nerve structure most commonly used by practitioners, was the weakest of the structural parameters to discriminate between normal and glaucoma. The combination of structural and functional measurements performed better than structural or functional measurements alone. When the discriminant function was applied to a group of 124 age-matched ocular hypertensives, 20% were assigned to the glaucoma group. Discriminant analysis of structural and functional measurements increases precision in identification of early glaucomatous damage, provides a probability that glaucomatous damage is present, and may help identify those ocular hypertensives who actually may have early damage.     

Retinal vessel diameter in normal and glaucomatous eyes: the Beijing eye study

Purpose: To assess retinal vessel diameter in adult Chinese with and without glaucoma. Methods: The population‐based, cross‐sectional study included 4439 of the 5324 subjects asked to participate (response rate 83.4%), all aged 40 years or older. This study was divided into a rural part (1973 subjects [44.4%]) and an urban part (2466 subjects [55.6%]). Colour optic disc and fundus photographs were morphometrically examined for 2418 subjects. The retinal vessel diameters were measured at the optic disc border and at a distance of 2 mm to the optic disc border. The main outcome measure was the retinal vessel diameter. Results: Diameters of the retinal arteries were significantly (P < 0.001) the widest in the temporal inferior region, followed by the temporal superior region (P < 0.001), the nasal superior region (P < 0.001) and finally the nasal inferior region. Except for the nasal inferior vein, the same held true for the retinal veins. The sequence of the main four vessel trunks with respect to their diameters was not associated with age, gender or hyperopia versus myopia. The artery diameters showed a tendency to decrease in older age, while the vein diameters decreased across all age groups. Eyes with glaucomatous optic nerve damage showed significantly (P < 0.001) thinner arteries while the retinal vein diameters were not different. Conclusions: Diameters of the retinal arterioles and veins are the widest in the temporal inferior arcade, followed by the temporal superior arcade, the nasal superior arcade and finally the nasal inferior arcade. Retinal artery diameters decrease with glaucoma, and retinal vein diameters decrease with age.     

Association of beta zone of parapapillary atrophy with age-related macular degeneration in adult Chinese. The Beijing Eye Study

BACKGROUND: Since parapapillary atrophy and age-related macular degeneration (AMD) share features of their ophthalmoscopic and histological appearance, such as irregular pigmentation, proliferation and loss of the retinal pigment epithelium, it was the purpose of the study to assess whether parapapillary atrophy, particularly beta zone of parapapillary atrophy, is associated with AMD in a population-based investigation. METHODS: The Beijing Eye Study included 4439 subjects out of 5324 subjects invited to participate (response rate 83.4%) with an age of 40 + years. The present investigation consisted of 3874 (82.3%) subjects for whom readable fundus photographs of at least one eye were available with normal intraocular pressure, a refractive error of >- 8 diopters, and no signs of glaucomatous optic neuropathy. RESULTS: In a multivariate analysis, beta zone of parapapillary atrophy was significantly associated with age (P < 0.001), optic disc size (P < 0.001) and myopic refractive error (P < 0.001). It was not significantly associated with presence of retinal pigment depigmentation (P = 0.20) or hyperpigmentation (P = 0.99), drusen size (P = 0.27), and presence of early AMD (P = 0.72) or late AMD (P = 0.99). CONCLUSIONS: Although beta zone of parapapillary atrophy and age-related macular degeneration have a similar histology with irregularities of the retinal pigment epithelium and eventual closure of the choriocapillaris and loss of retinal pigment epithelium cells, the entities are clinically not significantly associated with each other.     

Central retinal vessel trunk exit and location of glaucomatous parapapillary atrophy in glaucoma

OBJECTIVE: To evaluate whether the position of the central retinal vessel trunk exit on the lamina cribrosa spatially correlates with the location of parapapillary atrophy in glaucoma. DESIGN: Clinic-based, observational, cross-sectional study. PATIENTS: Color stereo optic disc photographs of 95 patients with primary or secondary open-angle glaucoma and 65 healthy persons were morphometrically evaluated. The intrapapillary and parapapillary region was divided into four quadrants. We determined the position of the central retinal vessel trunk exit on the lamina cribrosa surface and measured the area of parapapillary atrophy and neuroretinal rim in the four quadrants. MAIN OUTCOME MEASURES: The area of neuroretinal rim and parapapillary atrophy and the position of the central retinal vessel trunk exit. RESULTS: Comparing measurements between opposite disc quadrants showed that beta zone of parapapillary atrophy was significantly (P < 0.05) larger and that the neuroretinal rim was significantly smaller when beta zone and neuroretinal rim were measured in the disc quadrant most distant to the central retinal vessel trunk exit, than if the beta zone and neuroretinal rim were measured in the quadrant containing the vessel trunk exit. Comparing measurements in the disc quadrants between eyes with different positions of the central retinal vessel trunk exit revealed that, in the respective disc quadrant, the beta zone was significantly larger and the neuroretinal rim was smaller in eyes with the vessel trunk exiting in the opposite disc quadrant than in eyes with the vessel trunk exit located in the respective disc quadrant where the measurements were obtained. CONCLUSIONS: Position of the central retinal vessel trunk exit on the lamina cribrosa influences the location of parapapillary atrophy in glaucoma. The longer the distance to the central retinal vessel trunk exit, the more enlarged is parapapillary atrophy and the smaller is the neuroretinal rim. This relationship agrees with the spatial relationship between glaucomatous neuroretinal rim loss and enlarged parapapillary atrophy in glaucoma. Diagnostically, it may indicate that, in eyes with an abnormal configuration of parapapillary atrophy or with an abnormal position of the central retinal vessel trunk exit, early glaucomatous rim changes should be looked for in the disc sector that is most distant to the central retinal vessel trunk exit and where parapapillary atrophy may be relatively large.     

原发性青光眼不同区域多焦视觉诱发电位的研究

目的:比较正常人和原发性青光眼患者不同分区的多焦视觉诱发电位(multifocalvisualevokedpoten-tial,mfVEP),评价mfVEP在青光眼诊断中的作用。方法:采用法国VisionMonitor多焦视觉电生理仪的二阶kernel技术检测21例32只正常对照眼、37例58只原发性青光眼的mfVEP,将青光眼mfVEP振幅均方根(rootmeansquare,RMS)及潜伏期与正常对照眼行不同分区的比较。结果:正常眼mfVEP的RMS值个体间变异大(变异系数CV=43.05%)。青光眼mfVEP的RMS值在上下半视野,鼻上、颞上、鼻下、颞下四个象限及各个环形分区均较正常对照眼小,且在0～10°环形区域及鼻上象限差异有显著性意义(P<0.05),二者各个区域的潜伏期无差异。结论:正常人mfVEP个体间变异性大;青光眼患者mfVEP振幅较正常人下降,且在中央区域及鼻上象限更为显著。     

限定地区人群为基础的视盘旁萎缩弧形态学研究

目的评估限定地区人群为基础的视盘旁萎缩弧情况。设计限定地区人群为基础的横断面研究。人群5324个参与者中4439个人入选到本研究中,应答率为83.4%。最低年龄在40岁以上。其中农村人群为1973人(44.4%),城市人群为2466人(55.6%)。方法应用佳能彩色眼底照相机对眼底视盘拍照后,进行视盘形态学的评估。眼底照相机的放大倍数通过计算视盘的面积得到矫正。结果4163张清晰的眼底照片入选到本研究中,其中2955人(70.98%)有α区,平均面积为(0.729±0.629)mm2(0.053～13.719mm2)。α区的大小和年龄相关(r=0.194,p=0.000<0.001)。同时和近视的程度相关(r=-0.094,p=0.000<0.001)。男性和女性之间萎缩弧α区大小无明显统计学差异(p=0.045,95%CI:0.706,0.752)。而872人有β区(20.95%),平均值为(1.985±2.223)mm2(0.102～14.999)mm2。β区的大小和年龄相关(r=0.144,p=0.000<0.001)。和近视的程度相关(r=-0.556,p=0.000<0.001)。男性和女性之间的β区大小无明显差异(p=0.096,95%CI:-0.548,0.045)。α区和β区面积大小与人群的裸眼视力,最佳矫正视力有关。两种萎缩弧均易发于视盘的颞侧,其次为颞下、颞上,最少发生在视盘鼻侧。结论α区和β区各自在人群中的发生率为70.98%和20.95%。由于β区多发于青光眼人群,β区的正常人群研究资料可能对青光眼的早期发现有重要意义。     

In-vivo measurement of autofluorescence in the parapapillary atrophic zone of optic discs with and without glaucomatous atrophy

BACKGROUND: To assess the level of autofluorescence (lipofuscin) of atrophic parapapillary zones in different stages of glaucomatous optic disc atrophy. METHODS: Controlled cross-sectional prospective analysis of 79 consecutive eyes (15 normals as controls, 26 with ocular hypertension, 38 with primary open angle glaucoma). Eyes with retinal diseases or retinal pigment epithelial pathologies were excluded. The confocal scanning laser ophthalmoscope (HRA, Heidelberg Retina Angiograph) was used after lipofuscin excitation with argon blue laser (488 nm) to detect parapapillary autofluorescence in a spectrum above 500 nm. Size, extension of the parapapillary autofluorescent area and its mean distance to the optic nerve head were measured using the HRA standard software. Additional optic nerve head photographs taken with the 15 degrees Zeiss telecentric fundus camera (30 degrees camera with 2 x magnifier) were examined by two experienced ophthalmologists to determine the stage of glaucomatous optic disc atrophy (stages 0 to 4). RESULTS: Very small autofluorescent areas were found in vital discs (optic nerve glaucoma stage 0) in the parapapillary atrophic area (0.08 +/- 0.12 mm (2)) in contrast to glaucomatous discs in stage 1 (0.24 +/- 0.26 mm (2)) and stages 2, 3 and 4 (0.59 +/- 1.29 mm (2), logistic regression analysis r = 0.71; P = 0.029). The circular extension of the autofluorescent area correlated borderlined with the stage of the glaucomatous disc atrophy (higher glaucoma stages: r = 0.82; P = 0.09). The autofluorescent area was larger in OHT than in controls (0.11 mm (2) vs. 0.04 mm (2), P < 0.03). The circular extension of the autofluorescent area was longer in OHT than in controls (0.5 mm vs. 1.15 mm, P < 0.04). CONCLUSIONS: As a sign of pronounced lipofuscin accumulation in the parapapillary atrophic zone higher degrees of fundus autofluorescence can be detected in OHT and manifest primary open angle glaucoma in contrast to normals. The lipofuscin accumulation is correlated with the stage of progression of glaucoma and the stage of optic disc atrophy. The detection of active parapapillary autofluorescent areas especially in OHT may offer the ophthalmologist an important tool for early diagnosis.     

Differences in central corneal thickness between the paired eyes and the severity of the glaucomatous damage

Purpose

To evaluate whether a difference in central corneal thickness (CCT) between the paired eyes could be associated to worse glaucoma in the thinner cornea eye.

Methods

From 16 different glaucoma centres, at least 50 glaucomatous patients were saved on the Italian Glaucoma Register. Eight hundred and sixteen glaucomatous patients were found in the register. CCT, ophthalmoscopic cup/disc ratio, mean deviation (MD), pattern SD (PSD), and intraocular pressure (IOP). The difference (Δ) between the paired eyes was calculated for all the considered parameters and two subgroups were created on the basis of ΔCCT. Because the difference between the two eyes could be positive or negative, the absolute value of Δ was considered for all the measurements. Three different ΔCCT cutoffs were selected: 10, 15, and 20 μm. Student''s t-test was used to compare the subgroups.

Results

When the entire group was divided in two subgroups using 20 μm as ΔCCT cutoff, no significant difference was found for ΔIOP (−0.38±2.53 (mean±SD) mm Hg and −0.07±2.35 mm Hg, respectively) between the two subgroups. Significant (P<0.001) difference was found for ΔMD (6.58±7.30 and 3.14±4.22 dB, respectively), ΔPSD (3.92±4.01 and 2.16±2.57, respectively), and ΔC/D (0.11±0.14 and 0.08±0.11, respectively) between the two subgroups. No significant correlation was found between ΔCCT and the other parameters.

Conclusion

The ΔCCT between the two eyes could be associated to a worse glaucoma in the thinner cornea eye.     

The ultrastructure of parapapillary chorioretinal atrophy in eyes with secondary angle closure glaucoma

Background: The present study was performed to investigate the ultrastructure of deep retinal layers and choroid corresponding to the parapapillary chorioretinal atrophy in eyes with secondary angle-closure glaucoma. Methods: The glaucomatous eyes included two eyes enucleated due to iris ring melanoma with high intraocular pressure and one eye with neovascular glaucoma enucleated due to ocular pain. The control eyes included one eye enucleated due to choroidal malignant melanoma with normal intraocular pressure and one eye enucleated during surgery for supramandibular carcinoma. These eyes were studied with light and electron microscopy. Results: In the region of parapapillary chorioretinal atrophy of glaucomatous eyes, the retinal pigment epithelial cells showed degenerative changes, such as loss of basal in foldings and microvilli, degenerated mitochondria, vacuolar degeneration and irregular distribution of melanin granules. The photoreceptors were decreased in number in this area of glaucomatous eyes. The lumen of the choriocapillary vessels adjacent to the optic nerve was collapsed. Conclusion: These results elucidate the fine structures of deep retina and choroid in the region of parapapillary chorioretinal atrophy of glaucomatous eyes, and suggest that the reduced choroidal perfusion might be the pathogenetic mechanism of glaucomatous parapapillary chorioretinal atrophy.     

Aqueous humor inflow in normal and glaucomatous avian eyes

A new fluorometric method has been employed to measure inflow of aqueous humor (F) in normal and glaucomatous avian eyes. Most inflow determinations in previous studies have involved severe disturbance to the eye, or else F has been derived indirectly, as a function of outflow facility (C) or intraocular pressure (IOP). The procedure used in this study is readily accomplished, even with a large series of subjects, and F measurement involves no insult to the eye or extrapolations from parameters whose relationship to F is not fully understood. After inflow measurements had been completed, the same experimental animals were subjected to independent determinations of volume of the aqueous space, IOP, C, and several dimensional parameters, thus permitting a comprehensive assessment of aqueous fluid dynamics during eye development.     

Discrimination between normal and glaucomatous eyes with the Topographic Scanning System: a preliminary report.

BACKGROUND AND OBJECTIVE: To evaluate the ability of the Topographic Scanning System (TopSS; Laser Diagnostic Technologies, San Diego, CA) to differentiate individuals with glaucoma from normal subjects. PATIENTS AND METHODS: The subjects were divided into two groups: primary open-angle glaucoma and normal. All individuals underwent a complete ophthalmic evaluation, a 24-2 full threshold Humphrey visual field evaluation, and a TopSS examination. Cut-off points were selected, receiver operator characteristic (ROC) curves were created, and sensitivity and specificity were calculated for individual TopSS parameters and combinations of variables using multivariate analysis. RESULTS: One hundred twelve patients with glaucoma and 88 normal individuals were enrolled in the study. The best TopSS individual parameters were: average disc diameter (sensitivity: 64%, specificity: 89%, area under ROC curve: 0.824), total disc area (sensitivity: 85%, specificity: 66%, area under ROC curve: 0.802), and cup area (sensitivity: 69%, specificity: 85%, area under ROC curve: 0.797). The multivariate analysis resulted in an area under the ROC curve of 0.91 (sensitivity: 90%, specificity: 81%). CONCLUSIONS: This preliminary report suggests that the use of a multivariate discriminant formula may enhance the ability to differentiate individuals with glaucoma from normal subjects with the TopSS, with high sensitivity and specificity. Further studies investigating a random population are needed to test the validity of this formula.