Anterior visual pathway assessment by magnetic resonance imaging in normal-pressure glaucoma

PURPOSE: To analyze the axonal architecture of the optic nerve in patients with normal-pressure glaucoma and determine whether these parameters correlate with the disease severity. Methods: Using magnetic resonance (MRI) imaging (1.5-Tesla unit) and diffusion tensor (DT) MRI, we measured the optic nerve diameter, optic chiasm height and lateral geniculate nucleus (LGN) volume in patients with normal-pressure glaucoma and an age-matched control group. The retinal nerve fibre layer thickness (RNFL) was determined by optical coherence tomography (OCT). Results: The study included 30 patients with normal-pressure glaucoma and 30 age-matched control subjects. Optic nerve diameter (p < 0.001), optic chiasm height (p < 0.001) and LGN volume (p = 0.02) were significantly smaller in the glaucoma group than in the control group and were significantly correlated with RNFL thickness and perimetric loss. In the control group, the parameters significantly (p < 0.05) decreased with age. The DT-MRI-derived fractional anisotropy for the optic nerve was significantly lower (p < 0.001), and the DT-MRI-derived mean diffusivity (p < 0.001), radial diffusivity (λ(⊥) ; p < 0.001) and axial diffusivity (λ(||) ; p = 0.009) for the optic nerve were significantly higher in the glaucoma group and significantly correlated with RNFL thickness and mean perimetric defect. Conclusions: Patients with normal-pressure glaucoma show an age-adjusted reduced optic nerve diameter, optic chiasm height and LGN volume as measured by MRI, correlating with a reduced RNFL thickness and increased perimetric loss. MRI may be applied to examine the optic nerve in patients with glaucoma with opaque optic media.     

Assessment of optic nerve head topographic parameters with a confocal scanning laser ophthalmoscope

AIM: To assess the disc area, age, sex, laterality (side of the eyes) and refractive error dependent differences in optic nerve head topographic parameters in a normal population. METHODS: Optic nerve head topographic analysis of both eyes of 551 healthy Turkish subjects aged 11-75 years (1102 eyes) was performed using a confocal scanning laser ophthalmoscope, the Heidelberg Retinal Tomograph II (HRT II). The effects of disc size, sex, laterality (side of the eyes), age and refractive error on optic nerve head topographic parameters were assessed. Subjects were divided into three different age groups (<30 years, 30-60 years, >60 years) and three different disc area groups (<2.00 mm(2), 2.00-2.25 mm(2), >2.25 mm(2)). Disc area, topography standard deviation and a total of 12 topographic parameters were calculated by HRT II for each subject. Statistical analysis was performed using Student's t-test, multiple regression analysis, Tukey-HSD test, anova and Pearson's correlation coefficient. RESULTS: A total of 543 subjects (298 women and 245 men) were included in the study. The mean disc area of the subjects was 2.12 +/- 0.47 mm(2) (range 1.16-4.98 mm(2)). The mean refractive error of the subjects was -0.58 +/- 1.71 D (range -4.75 D to +4.25 D). The mean cup shape measure was -0.21 +/- 0.07 (95% confidence interval -0.07 to -0.35). The disc area was significantly correlated with all of the topographic parameters but two; namely, the cup shape measure and the height variation contour. Significant age-related differences were detected in four parameters (mean retinal nerve fibre layer [RNFL] thickness, disc area, cup-to-disc area ratio, cup area) and significant sex-related differences were detected three parameters (mean RNFL thickness, height variation contour, RNFL cross-sectional area). However, there were no significant differences in any of the parameters for laterality and refractive error. The parameter cup shape measure did not correlate with any of the five variables investigated. CONCLUSION: Cup shape measure was the only optic nerve head topographic parameter that was independent of age, sex, disc area, laterality and the refractive error. It seems to be a promising parameter in evaluation and comparison of the optic discs of normal subjects, with different disc area, age, sex, refraction error and laterality, as being independent of the main variation factors of the disc topography.     

海德堡视网膜断层扫描仪测量正常人视盘参数

目的 :建立正常人群海德堡视网膜断层扫描仪 (Heidelbergretinatomograph ,HRT)视盘参数的正常值 ,明确哪些因素对正常人HRT视盘参数有影响。方法 :选用 10 2例 (13 2只眼 )正常人 ,用HRT进行视盘扫描 ,视盘参数包括视盘面积、视杯面积和容积、盘沿面积和容积、视杯形态、视杯平均深度和最大深度、杯 /盘面积比、沿 /盘面积比、平均视网膜神经纤维层(retinalnervefiberlayer,RNFL)厚度和横截面积、水平C/D和垂直C/D。计算正常人视盘参数范围 ,用直线回归的方法判断视盘大小和年龄对视盘参数的影响。结果 :正常人左右眼和男女间视盘各参数差异无显著意义 (P >0 0 5)。年龄与RNFL厚度及横截面积呈负相关 ,相关系数分别为 -0 2 3 4和 -0 2 3 5,其余各参数与年龄无关。盘沿容积和视杯最大深度不受视盘大小的影响 ,其余各参数均与视盘大小呈线性相关。结论 :HRT可定量检测正常人视盘参数 ;正常人视盘参数变异很大 ,盘沿容积不受视盘大小的影响 ,是一个区分正常与早期青光眼的很好的参数     

Effect of the menstrual cycle on standard achromatic and blue-on-yellow visual field analysis of women with migraine

BACKGROUND: It has been postulated that migraine and glaucoma may have common vascular causative factors. Significant sex-based differences in the incidence of many important ocular conditions raise the possibility that estrogens may have direct effects on the eye. We performed a study to determine the effect of the menstrual cycle on standard achromatic automated perimetry (SAP) and short-wavelength automated perimetry (SWAP) (blue-on-yellow perimetry) of women with migraine. METHODS: Both eyes of 73 normally menstruating women (31 subjects with migraine and 42 healthy control subjects) were included in the study. Subjects underwent a complete ocular examination including SAP and SWAP in both the follicular phase (12th to 13th day of the cycle) and the luteal phase (1 to 2 days before the onset of bleeding) of two consecutive menstrual cycles.We performed visual field analysis using the Humphrey Field Analyzer II with the full-threshold central 30-2 program. Mean sensitivity was calculated for the superior temporal, inferior temporal, superior nasal and inferior nasal regions separately. RESULTS: Thirteen subjects were lost to follow-up (5 in the migraine group and 8 in the control group), leaving 26 subjects and 34 subjects respectively. There was no significant difference in mean age between the two groups (33.9 years [standard deviation (SD) 3.4 years] vs. 35.1 years [SD 3.3 years]). The mean duration of migraine was 7.6 (SD 3.1) years (range 3-14 years). In both groups, serum estradiol levels were significantly lower (p = 0.001) and serum progesterone levels were significantly higher (p < 0.001) in the luteal phase than in the follicular phase. In the control group, the mean sensitivity values with SWAP were significantly lower in the luteal phase than in the follicular phase (p = 0.04). A similar decrease was observed for the subjects with migraine with both SAP and SWAP (p = 0.01). There was no difference in regional mean sensitivity between the two phases with either perimetric test in the control group. For the subjects with migraine, there was no difference in regional mean sensitivity between the two phases with SAP. However, with SWAP, the mean sensitivity for the nasal visual field locations was significantly lower in the luteal phase than in the follicular phase (p = 0.01). INTERPRETATION: Our study provides further evidence of an effect of sex hormones on the visual field of women with migraine. In addition to assessment of intraocular pressure, menstrual cycle phases should be considered in women with migraine at risk for glaucomatous optic neuropathy.     

Retinal nerve fiber layer measurements using laser scanning polarimetry in different stages of glaucomatous optic nerve damage

PURPOSE: To evaluate the diagnostic value of polarimetric measurements of the retinal nerve fiber layer (RNFL) thickness in different stages of glaucomatous optic nerve damage. METHODS: The study included 92 eyes of 46 controls (age 41.0+/-13.7 years) and a heterogeneous group of 232 eyes of 135 patients with different stages of glaucomatous optic nerve damage (age 54.0+/-10.2 years; 68 patients with primary open-angle glaucoma, 56 with normal-pressure glaucoma and 11 patients with secondary glaucoma due to primary dispersion syndrome or pseudoexfoliation syndrome). All control subjects and patients underwent complete ophthalmological examinations including scanning laser polarimetry of the RNFL using the GDx (Laser Diagnostic Technologies, San Diego, Calif.) and 15 degrees color stereo optic disc photographs. Only subjects and patients with disc area less than 3.4 mm(2) were included in the study. The total glaucoma group were divided into four subgroups according to the morphological criteria of the neuroretinal rim. RESULTS: The stage of morphological glaucomatous optic nerve damage was classified as follows: stage 0: n=92, stage 1: n=103, stage 2: n=65, stage 3: n=40, and stage 4: n=19. Differences in mean polarimetric retardation between controls and eyes with glaucoma were significant for all parameters except the variable symmetry. The most significant differences between controls and eyes with glaucomatous optic nerve damage were found with the "number" variable assigned by the neural network analysis ( P<0.001). With increasing stage of glaucomatous optic nerve damage, separation of the variable "the number" increased significantly. At a predetermined specificity of 90% the sensitivity of the groups with different stages of morphological glaucomatous optic nerve damage increased from 32% for stage 1 to 90% for stage 4. CONCLUSION: Polarimetric measurement of the RNFL thickness is significantly associated with morphological glaucomatous optic nerve damage. The fast performance, easy handling, and low cost of RNFL polarimetry mean that it can be included in the routine examination of glaucoma patients. Further study and refinement of this technique are indicated to improve its usefulness in both clinical diagnosis and in population-based case identification.     

Optic nerve functions and visual evoked potential after acute optic neuritis

目的:比较视神经炎患者和正常人的视神经功能与视觉诱发电位.方法:本研究为2011年9月至2013年2月在马来西亚大学眼科医院进行的横断面研究.研究包含在检查前3mo至2y间发生特发性神经炎一次的视神经炎患者20例和10例正常人.眼科检查包括视力、色觉、视觉灵敏度、视野和视觉诱发电位.独立t检验用于比较视神经炎组与对照组视神经功能和VEP参数的差异.在参数非正态分布时,Mann-Whitney试验用于比较两组间的中位数.结果:视神经炎组的平均年龄为30.8岁.在视神经炎发作至评估期间的平均持续时间为6.6个月.视神经炎组视力较差,平均LogMAR值(0.52)明显高于对照组(P=0.001).色觉下降,视神经炎组的平均值为63%(P=0.001).视神经炎患者的对比敏感度在四个空间频率上均有所下降 [3CPD(P=0.029),6CPD(P=0.026),12CPD(P=0.002)、18CPD(P=0.006)].视神经炎组的视野下降有统计学意义(P<0.001).与对照组相比,视神经炎组的VEP P100潜伏期有轻微延长.但使用棋盘格模式1或2时,VEP潜伏期的差异不显著.视神经炎患者的VEP振幅较高,但两组差异无统计学意义.结论:视神经炎急性发作,平均6mo后视神经功能(即视力、色觉、对比敏感度和视野)显著下降.视神经炎组和对照组的VEP振幅和潜伏期无显著差异.VEP可能不是理想的诊断视神经炎既往发作史的试验,尽管VEP参数在浮动后趋于正常.     

Scanning laser polarimetry with variable corneal compensation in migraine patients

Purpose: This study aimed to compare scanning laser polarimetry measurements of retinal nerve fibre layer (RNFL) thickness in eyes of migraine patients with those in eyes of age‐matched, healthy subjects. Methods: The study was designed as an observational, prospective, cross‐sectional study. It included 57 eyes of 57 patients with migraine with or without aura according to the criteria of the International Headache Society and 44 eyes of 44 age‐matched healthy controls. Scanning laser polarimetry images were obtained using a commercial GDx VCC system (Version 5.3.1; Laser Diagnostic Technologies, Inc.). At each sitting, three sets of GDx VCC measurements were acquired for each patient and used in the analysis. Image acquisition was performed in undilated eyes in all subjects. Results: The mean ± standard deviation RNFL average thickness parameter in the migraine subjects was significantly lower than in the control group, at 50.4 ± 4.8 μm versus 54.7 ± 3.4 μm, respectively (p < 0.0001). However, there were no differences between migraine subjects and controls in mean RNFL thickness in superior and inferior areas. In the migraine group the mean migraine disability assessment (MIDAS) score was 34.3 ± 15.3 and the mean number of attacks per year was 17.1 ± 6.9 (range 6?28). The mean RNFL average thickness parameter was significantly correlated with MIDAS score (r = ? 0.86, p < 0.0001) and frequency of attacks (r = ? 0.86, p < 0.0001). Conclusions: The mean RNFL average thickness parameter was found to be thinner in migraine patients. In addition, we found a strong correlation between migraine severity and RNFL average thickness parameters.     

Optic nerve head, retinal nerve fiber layer, and macular thickness measurements in young patients with retinitis pigmentosa

Purpose: To evaluate optic nerve head (ONH) parameters, peripapillary retinal nerve fiber layer (RNFL) thickness, and macular thickness by using Cirrus HD spectral-domain optical coherence tomography (OCT) in young patients with retinitis pigmentosa (RP). Methods: ONH parameters, RNFL thickness, and macular thickness were measured and compared between 36 eyes from 36 young RP patients (RP group; mean age, 23.08 years) and 70 eyes from 70 healthy young subjects (control group; mean age, 22.66 years) using Cirrus HD-OCT. The effects of the presence of optic disc pallor and the severity of visual field (VF) defects on OCT parameters were also evaluated. Results: The RP group had a greater rim area, smaller cup-to-disc ratio, smaller cup volume, thicker RNFL, and thinner macula than the control group (p ≤ 0.024). ONH parameters were not affected by the presence of optic disc pallor (p ≥ 0.239). Eyes with more severe VF defects (mean deviation ≤ -13.88 dB) had thinner average macular areas than eyes with less severe VF defects (mean deviation ≥ -13.88 dB; p = 0.002). Meanwhile, the ONH parameters and average peripapillary RNFL thickness were not significantly different between the two groups (p ≥ 0.275). Conclusions: Young eyes with RP exhibited different OCT parameters compared to healthy eyes. Among the various OCT parameters, only macular thickness was associated with disease severity. These findings should be considered when evaluating young RP patients.     

Retinal abnormalities in early Alzheimer's disease

PURPOSE: There is evidence suggesting that visual disturbances in patients with Alzheimer's Disease (AD) are due to pathologic changes in the retina and optic nerve, as well as to higher cortical impairment. The purpose of this study was to evaluate retinal hemodynamic parameters and to characterize patterns of retinal nerve fiber layer (RNFL) loss in patients with early AD. METHODS: Nine patients with mild to moderate probable AD (mean Mini Mental State Examination score 24 of a possible 30 (age 74.3 +/- 3.3 years; mean +/- SD) and eight age-matched control subjects (age, 74.3 +/- 5.8 years) were included in this prospective cross-sectional study. Blood column diameter, blood velocity, and blood flow rate were measured in the major superior temporal retinal vein in each subject by using a laser Doppler instrument. Peripapillary RNFL was measured by optical coherence tomography. RESULTS: Patients with AD showed a significant narrowing of the venous blood column diameter (131.7 +/- 10.8 microm) compared with control subjects (148.3 +/- 12.7 microm, P = 0.01), and a significantly reduced venous blood flow rate (9.7 +/- 3.1 microL/min) compared with the control subjects (15.9 +/- 3.7 microL/min, P = 0.002). A significant thinning of the RNFL was found in the superior quadrant in patients with AD (92.2 +/- 21.6 microm) compared with control subjects (113.6 +/- 10.7 microm, P = 0.02). There were no significant differences in the inferior, temporal, or nasal RNFL thicknesses between the groups. CONCLUSIONS: Retinal abnormalities in early AD include a specific pattern of RNFL loss, narrow veins, and decreased retinal blood flow in these veins. The results show that AD produces quantifiable abnormalities in the retina.     

Laser scanning tomography of the optic nerve head in a normal elderly population: the Bridlington eye assessment project

PURPOSE: To assess optic nerve head topographic parameters using the Heidelberg Retina Tomograph (HRT) II (Heidelberg Engineering GmbH, Dossenheim, Germany) in a normal elderly population. METHODS: Optic nerve head analysis of 918 eyes of 459 normal elderly patients was performed. All patients were consecutive in a cohort screened for eye disease. Normal subjects were defined with a normal visual field on automated suprathreshold screening, intraocular pressure less than 22 mmHg, and minimum corrected visual acuity of 6/12. All optic discs were contoured by two investigators and the mean parameters analyzed. The effects of age, sex, and disc size were assessed. RESULTS: Subjects' (262 women and 197 men) mean age was 72.6 +/- 5.1 (SD) years (range, 65.5-89.3). Mean +/- SD global disc area, cup/disc area ratio, and neuroretinal rim area were 1.98 +/- 0.36 mm2, 0.22 +/- 0.14, and 1.52 +/- 0.31 mm2, respectively. Disc area did not differ significantly based on eye side or sex. The women were found to have a significantly larger rim volume, mean retinal nerve fiber layer (RNFL) thickness, and cross-sectional area than the men and tended to have smaller cup areas/volumes and cup/disc area ratios. Most tomography parameters were found to be significantly influenced by disc size. CONCLUSIONS: To the authors' knowledge, this is the first large study of optic nerve head parameters in the elderly normal population using the HRT II. This age range is particularly relevant to glaucoma detection and pertinent to discriminant analyses separating normal subjects from glaucoma in screening for the disease. Given the systematic differences between the parameters in men and women, reference ranges should be quoted by sex.     

Telemedical assessment of optic nerve head and retina in patients after recent minor stroke or TIA

The aim of the study is to telemedically assess the prevalence of simple optic nerve atrophy and retinal arteriolar anomalies in subjects who have had a minor stroke or TIA within 14 days, and to compare these results with an age-matched control group. By using a mobile examination unit, retinal photographs were taken with a 45° non-mydriatic colour fundus camera (KOWA NM-45, non-mydriatic-alpha) in patients who had suffered from a minor stroke or TIA within 14 days of the time of the examination. Retinal photographs were focused on the optic nerve head region. Pupils were not dilated. The documented medical history and the retinal images were stored on a server using browser independent web-based software running on PCs, tablets and smartphones. After completing the upload of the medical interview and the retinal images into the electronic patient chart, all retinal images were evaluated via telemedicine by an experienced senior consultant ophthalmologist. Age-matched normotensive, non-diabetic subjects (aged 40–89 years) who reported no systemic or ocular diseases were used as the control group. Both study groups were divided into five decades of life (40–49; 50–59; 60–69; 70–79; 80–89 years). We calculated the prevalences and the ratios of prevalences of optic nerve atrophy and retinal arteriolar anomalies between the stroke and the control group per decades of life. 139 minor stroke or TIA subjects (aged 40–89 years) and 1611 age-matched control subjects were examined. In the stroke group, we found significantly increased prevalences of optic nerve atrophy and retinal arteriolar anomalies throughout the 5th–8th decade of life when compared to age-matched controls. The prevalence of optic nerve atrophy in stroke subjects outranged the prevalence in the controls depending on age-class by a factor of 3–21. Simple optic nerve atrophy is frequent in patients who have suffered from an ischemic stroke or TIA, and it seems to indicate vascular damage, indicating the necessity for telemedically assisted assessment of the optic nerve.     

Visual field defect and perfusion of the juxtapapillary retina and the neuroretinal rim area in primary open-angle glaucoma

• Background: At this time little information is available about the relationship between glaucomatous visual field defects and impaired blood flow in the optic nerve head. The purpose of this study was to examine blood flow of the juxtapapillary retina and the rim area of the optic nerve head in primary open-angle glaucoma with a borderline visual defect. • Methods: Juxtapapillary retinal and neuroretinal rim area blood flow was measured by scanning laser Doppler flowmetry (SLDF). The visual field was evaluated by static perimetry (Octopus-G1). The optic nerve head was assessed on 15° color stereo photographs. We examined 116 eyes of 91 patients with POAG with controlled IOP and 66 eyes of 44 healthy individuals. The POAG group was divided into eyes with a mean defect lower than 2 dB (POAG group I) and in eyes with a mean defect equal to or greater than 2 dB (POAG group II). The mean age of POAG group I and POAG group II was 55±11 years and 57±10 years, respectively. The mean age of the control group was 45±15 years. The eyes of POAG group I had an average C/D ratio of 0.71±0.18 with an average mean defect of the visual field of 0.97±0.68 dB; the eyes of POAG group II had an average C/D ratio of 0.80±0.17 with an average mean defect of the visual field of 8.2±6.0 dB. The intraocular pressure on the day of measurement in POAG group I was 18.2±3.7 mmHg, in POAG group II 17.6±4.0 mmHg, and in the control group 15.1±2.5 mmHg. For statistical analysis, age-matched groups of 32 normal eyes of 32 subjects (mean age 52±10 years) were compared to 18 glaucomatous eyes of 18 patients (POAG group I, mean age 55±11 years) and 59 glaucomatous eyes of 59 patients (POAG group II, mean age 55±10 years). • Results: In the eyes of POAG group I and POAG group II, both juxtapapillary retinal blood flow and neuroretinal rim area blood flow were significantly decreased compared to an age-matched control group: neuroretinal rim area “flow” POAG group I −65%, POAG group II −66%; juxtapapillary retina “flow” POAG group I −52%, POAG group II −44%. All eyes of the POAG group I (MD<2 dB) and 56 of 61 eyes of the POAG group II (MD>=2 dB) showed a retinal perfusion lower than the 90% percentile of normal blood flow. We found no correlation between reduction of juxtapapillary or papillary blood flow and mean defect in POAG eyes. • Conclusion: Glaucomatous eyes with no defects or borderline visual field defects as well as glaucomatous eyes in an advanced disease stage show significantly decreased optic nerve head and juxtapapillary retinal capillary blood flow. Received: 2 December 1996 Revised version received: 7 February 1997 Accepted: 27 March 1997     

Heidelberg retina tomograph in ocular Behçet's disease

PURPOSE: To compare the optic disc topography of patients with ocular Beh?et's disease (BD) with age-matched controls, using Heidelberg retina tomograph (HRT). METHODS: This study included 32 patients (51 eyes) with ocular BD (active and/or inactive), 38 patients (74 eyes) with nonocular BD, and 62 normal subjects (62 eyes). All patients and control group underwent complete ophthalmologic evaluation. Intraocular pressure was less than 22 mmHg in patients and in the control group. The optic nerve heads of all subjects were imaged with the HRT (software 2.01a-M). The following stereometric parameters were calculated for each patient: disc area, cup area, cup/disc area ratio, rim area, height variation contour, cup volume, rim volume, mean cup depth, cup shape measure, mean RNFL thickness, and RNFL cross-sectional area. Differences among the groups were evaluated by Kruskal-Wallis variance analysis. When the Kruskal-Wallis test revealed a significant difference between groups, multiple comparison tests were used to find out which groups differed from which others. RESULTS: The mean disc area was significantly smaller (P<0.05) in patients with ocular and nonocular BD. The mean cup area, mean cup depth, and mean cup volume were significantly smaller (P<0.05) in patients with ocular BD. No significant differences were found between the groups in terms of the other stereometric parameters (P>0.05). CONCLUSION: A small disc and cup may be an additional risk factor for retinal vaso-occlusion in ocular Beh?et's disease.     

Histomorphometry of the human optic nerve

This study was undertaken to measure number, diameter and distribution of nerve fibers in normal human optic nerves. Twenty-two optic nerves of 19 subjects aged between 20 and 75 years were histomorphometrically examined using semithin sections obtained in a distance of 2 to 5 mm behind the globe. The mean nerve fiber count was 1,159,000 +/- 196,000 with a minimum of 816,000 and a maximum of 1,502,000. The significant (P = 0.025) loss per year of age was approximately 5426 nerve fibers. For eight subjects the nerve fiber count was independent of the size and form of the optic disc. The mean minimal nerve fiber diameter averaged 1.00 +/- 0.06 micron (range: 0.1-8.3 microns). It was significantly smaller in the temporal and inner region of the optic nerve than in the nasal and outer area, respectively. Correspondingly, nerve fiber count per area was significantly higher in the temporal and inner parts of the optic nerve than in the nasal and outer parts, respectively. Statistically different size classes could not be detected. The optic nerve cross-section area excluding the leptomeninges (mean 8.09 +/- 1.38 mm2) increased significantly with the nerve fiber count. The marked interindividual variability of the nerve fiber count may influence interindividual comparisons of psychophysical examinations. It can indicate an interindividually different anatomic "reserve capacity" in the course of optic nerve diseases. The age-dependent nerve fiber loss, among other factors, may partially explain the decreased visual performance of older subjects. It should be considered in progression and "pseudoprogression" of optic nerve diseases like glaucoma. The intraindividually high variability of the nerve fiber size may correspond to different retinal ganglion cell populations.     

Optic disc morphology in south India: the Vellore Eye Study

AIM: To evaluate the morphology of the optic nerve head in an unselected population group in south India. METHODS: The study included 70 subjects forming a population based sample, selected in a random manner. Mean age was 47.5 (SD 8.7) years, mean refractive error measured -0.07 (1.11) dioptres (range -4.50 to +2.50 dioptres). Optic disc slides were morphometrically analysed. RESULTS: Mean optic disc area measured 2.58 (0.65) mm(2). It was statistically independent of age and refractive error. Optic disc shape was slightly vertically oval. Mean neuroretinal rim area was 1.60 (0.37) mm(2). It was significantly and positively correlated with optic disc size and optic cup size. It was independent of age, sex, refractive error, and axial length. In all subjects included in the study, the rim was smallest in the temporal horizontal optic disc sector. Mean horizontal cup/disc diameter ratio (0.66 (0.07)) was significantly (p<0.001) higher than the mean vertical cup/disc diameter ratio (0.56 (0.08)). Both ratios were highly significantly (p <0.001) and positively correlated with optic disc size. The alpha zone of parapapillary atrophy (0.84 (0.29) mm(2)), and beta zone (0.13 (0.38) mm(2)), respectively, occurred in 69 (98.6%) subjects and in eight (11.4%) subjects, respectively. They were significantly larger in the temporal horizontal sector. The alpha zone was significantly (p<0.001) larger and occurred significantly more often than beta zone. Retinal arterioles and venules were wider, and in spatial correlation, the visibility of the retinal nerve fibre layer was significantly better, in the temporal inferior disc arcade and the temporal superior arcade than in the nasal superior arcade and the nasal inferior vessel arcade. Except for the absolute size measurements these optic nerve head parameters did not differ markedly (p >0.05) from the values found in white people. CONCLUSIONS: South Indians and white people do not show marked differences in the morphology of the optic nerve head as measured by morphometric optic disc parameters, with the possible exception of the absolute optic disc dimensions.     

Anterior visual pathway assessment by magnetic resonance imaging in normal‐pressure glaucoma

Purpose: To analyze the axonal architecture of the optic nerve in patients with normal‐pressure glaucoma and determine whether these parameters correlate with the disease severity. Methods: Using magnetic resonance (MRI) imaging (1.5‐Tesla unit) and diffusion tensor (DT) MRI, we measured the optic nerve diameter, optic chiasm height and lateral geniculate nucleus (LGN) volume in patients with normal‐pressure glaucoma and an age‐matched control group. The retinal nerve fibre layer thickness (RNFL) was determined by optical coherence tomography (OCT). Results: The study included 30 patients with normal‐pressure glaucoma and 30 age‐matched control subjects. Optic nerve diameter (p < 0.001), optic chiasm height (p < 0.001) and LGN volume (p = 0.02) were significantly smaller in the glaucoma group than in the control group and were significantly correlated with RNFL thickness and perimetric loss. In the control group, the parameters significantly (p < 0.05) decreased with age. The DT‐MRI‐derived fractional anisotropy for the optic nerve was significantly lower (p < 0.001), and the DT‐MRI‐derived mean diffusivity (p < 0.001), radial diffusivity (λ_⊥; p < 0.001) and axial diffusivity (λ_||; p = 0.009) for the optic nerve were significantly higher in the glaucoma group and significantly correlated with RNFL thickness and mean perimetric defect. Conclusions: Patients with normal‐pressure glaucoma show an age‐adjusted reduced optic nerve diameter, optic chiasm height and LGN volume as measured by MRI, correlating with a reduced RNFL thickness and increased perimetric loss. MRI may be applied to examine the optic nerve in patients with glaucoma with opaque optic media.     

Reduction of oscillatory potentials and photopic negative response in patients with autosomal dominant optic atrophy with OPA1 mutations

PURPOSE: To study the electroretinographic (ERG) findings in patients with autosomal dominant optic atrophy (ADOA) with OPA1 mutations. METHODS: Eight ADOA patients (age range, 24-55 years; mean, 41 years) with OPA1 mutations were studied. In addition to routine ophthalmological tests, full-field ERGs including the rod response, mixed rod-cone response, oscillatory potentials (OPs), single-flash cone response, and photopic negative response (PhNR) were recorded and compared with those from 25 age-matched controls. The correlation between the ERG data and averaged retinal nerve fiber layer (RNFL) thickness around the optic disk measured by optical coherent tomography, mean deviation of the static perimetry (Humphrey 30-2 program), or corrected visual acuity was also examined. RESULTS: Amplitudes of the PhNR and OPs, both of which are believed to originate from inner retinal layers, were significantly smaller in ADOA patients than in control subjects (P < 0.01). Amplitudes of other ERG components were not statistically different in the two groups. OP amplitude was inversely correlated with the patient's age. The RNFL was thinner and the retinal sensitivities obtained by static perimetry were lower in ADOA patients, but these values were not correlated with the amplitude of PhNR or OPs. CONCLUSIONS: These results suggested that there are functional impairments not only in the ganglion cell layer but also in the inner nuclear and plexiform layers, including the amacrine cells of ADOA patients with OPA1 mutations.     

Evaluation of Relative Afferent Pupillary Defect Using RAPDx Device in Patients with Optic Nerve Disease

We previously reported the standard values of the amplitude and latency scores in the RAPDx device for evaluating relative afferent pupillary defect (RAPD). Here, we evaluated RAPD in patients with optic nerve disease by using these standard values. Twenty-eight patients with current or previous optic nerve disease were enrolled in this study. Additionally, the data of 84 healthy subjects from our previous report were used as control data. We measured the amplitude and latency scores using RAPDx. We then compared their mean values and the percentages of individuals with standard values within a certain range between the optic nerve disease group and healthy group. Additionally, we evaluated their correlation with visual acuity and the critical flicker fusion frequency in the optic nerve disease group. Both parameters were significantly higher in the optic nerve disease group than in the control group (p < 0.0001). The detection rate of RAPD when using the standard value of amplitude score was 75%. Additionally, both parameters showed a significant correlation with laterality-based differences in visual acuity and critical flicker fusion frequency values in the optic nerve disease group (r = 0.59–0.75, p < 0.001). The amplitude and latency scores determined using RAPDx are useful in evaluating RAPD, particularly the standard value of the amplitude score.     

Optic disc morphometry correlated with confocal laser scanning Doppler flowmetry measurements in normal-pressure glaucoma

PURPOSE: To examine the relationship between morphologic optic disc parameters and hemodynamic parameters as measured by confocal laser scanning Doppler flowmetry in patients with normal-pressure glaucoma. METHODS: The study included 91 eyes of 54 patients with normal-pressure glaucoma (mean age: 57.7 +/- 9.8 years), and 136 eyes of 77 age-adjusted normal controls. Color stereo optic disc photographs were morphometrically examined, and confocal laser scanning flowmetry (Heidelberg Retinal Flowmeter) in the neuroretinal rim inside of the optic disc, and in the retina close to the temporal and nasal border of the optic nerve head was performed. RESULTS: Mean confocal laser scanning flowmetric measurements in the neuroretinal rim, temporal parapapillary retina, and nasal parapapillary retina were significantly (P<0.03) lower in the normal-pressure glaucoma group than in the age-adjusted control group. Correspondingly, mean confocal laser scanning flowmetric measurements within the neuroretinal rim decreased significantly, with relatively low correlation coefficients, decreasing neuroretinal rim area (P = 0.016; correlation coefficient r2 = 0.026), and increasing mean visual field defect (P = 0.011; r2 = 0.029). Measurements were statistically independent of alpha zone (P = 0.38; r2 = 0.004) and beta zone (P = 0.57; r2 = 0.002) of parapapillary atrophy. CONCLUSIONS: Confocal laser scanning flowmetric measurements within the neuroretinal rim were lower in eyes with normal-pressure glaucoma than in age-matched normal eyes. Confocal laser scanning flowmetric measurements decrease with increasing glaucomatous optic nerve damage. There is, however, a marked variability preventing a clear relationship between stage of glaucoma and decrease in confocal laser scanning flowmetric measurements. The correlation between parapapillary atrophy and confocal laser scanning flowmetric measurements is not statistically significant in normal-pressure glaucoma.     

应用3D-OCT对不同角膜厚度的高眼压症患眼CP-RNFL和视盘及黄斑区参数的研究

目的:观察不同中央角膜厚度(CCT)的高眼压症(OHT)患者环视盘神经纤维层厚度(CP-RNFL)、视盘及黄斑区参数的差异,并与正常人群对比,探讨CCT与各参数的关系。方法:前瞻性临床病例对照分析。纳入2016-01/2019-01在广东医科大学附属医院眼科确诊的OHT患者77例124眼进行研究。所有患者均未曾用药治疗。依据CCT的厚度分为3组:组1(CCT<555μm)25例38眼,组2(CCT 555~590μm)26例44眼,组3(CCT>590μm)26例42眼,选取同期年龄、性别、眼别均与高眼压组相匹配的健康体检者77例124眼为正常对照组。所有受检者均行视盘及黄斑三维光相干断层扫描(OCT)检查。运用系统自带软件计算平均CP-RNFL及各象限CP-RNFL的厚度及视盘、黄斑区各参数。结果:组1的OHT患者比正常对照组盘沿面积变小;相比组2,组3的患者,其下方CP-RNFL厚度变薄,盘沿的面积变小;相比组3的患者,其黄斑区内环颞侧视网膜厚度变薄。三组高眼压组患者的黄斑中心凹、中心1mm、内环颞侧视网膜厚度较正常对照组变薄;CCT与盘沿面积呈正相关(均P<0.05)。结论:尽管OHT患者的RNFL和视盘及黄斑区各参数在正常范围,但与正常人群对比还是有差异;CCT<555μm可能是OHT向开角型青光眼(POAG)转变的危险因素,临床上需要加强随诊及早期干预。