自适应光学成像系统（MICRO/ZSC-1）活体测定正常人眼视锥细胞密度

目的 对视网膜自适应光学成像系统所得视锥细胞图像进行处理,获取正常人眼底不同区域视锥细胞密度,探讨自适应光学成像系统用于眼科临床实验研究的可行性.方法 横断面研究.利用自适应光学成像系统采集30例正常受试者不同区域视锥细胞图像,对图像进行处理获得正常人眼视网膜不同区域的视锥细胞密度,并采用回归分析法对不同区域的密度进行曲线估计.结果 随测量点与黄斑中心凹的距离增加,视锥细胞密度呈现出降低的趋势.偏离黄斑中心凹0.5°到3°范围内,随着偏离度的增加,视锥细胞密度从70 000个/mm2下降到16 000个/mm2.结论 自适应光学成像系统能够在活体人眼获取清晰的高分辨率视网膜图像,可能可以在眼科临床实验研究中发挥一定的作用.     

Photoreceptor function in eyes with macular edema

PURPOSE: The irreversible loss of visual acuity in macular edema is usually attributed to permanent loss of photoreceptor cells, although there is hardly any information on changes in photoreceptor function in macular edema. The purpose of this study was to assess photoreceptor function in various stages of macular edema and to relate the findings to visual acuity and angiographic changes. METHODS: Directional sensitivity (optical Stiles-Crawford effect) and visual pigment density of foveal cones was measured with a custom-built scanning laser ophthalmoscope (SLO) in 19 eyes of 19 patients. Twelve eyes exhibited macular edema: five of inflammatory origin, and seven of diabetic origin. Seven eyes with an intraocular inflammatory disease without clinical or angiographic evidence of edema were also included (four of which had previous macular edema and one of which had shown development of macular edema at the 1-year follow-up). Results of SLO measurements were related to findings using fluorescein angiography and Snellen visual acuity, both assessed at the time of SLO measurement and 6 months thereafter. RESULTS: Eyes with macular edema exhibited diminished directional sensitivity of photoreceptor cells in the fovea compared with eyes without (P = 0.02). Visual pigment density of eyes with macular edema was decreased and associated with both initial and follow-up visual function and with the angiographic macular edema grade at follow-up. Abnormal directional sensitivity and pigment density were already present in eyes with slight edematous changes and normal visual acuity. CONCLUSIONS: Eyes with inflammatory or diabetic macular edema showed decreased directional sensitivity and visual pigment density in the macular area. These findings may support a role for SLO measurements in detecting retinal damage due to macular edema.     

Feasibility of screening for high-risk age-related macular degeneration with an Internet-based automated fundus camera.

BACKGROUND AND OBJECTIVE: The objective of this pilot study was to determine whether a new screening system, the DigiScope (EyeTel Imaging, Inc., Columbia, MD), can detect the presence of age-related macular degeneration (AMD) at a level requiring referral to an ophthalmologist for further evaluation and possible treatment. PATIENTS AND METHODS: The DigiScope is an Internet-based semi-automated digital imaging system designed to be in primary care physicians' offices. Forty-two eyes of 21 patients with different categories of AMD were imaged with both the DigiScope and a standard color fundus camera. The imaging capability of the two modalities was compared for identification of lesions associated with AMD and classification into stages. RESULTS: There was good agreement for low-risk lesions and excellent agreement for high-risk lesions. Thirty-five of 36 eyes with intermediate or advanced disease were correctly identified with DigiScope images. Choroidal neovascularization was identified in all cases with the DigiScope due to the presence of subretinal hemorrhage or subretinal fibrosis. The DigiScope was found less capable of detecting subretinal fluid than standard stereo fundus photographs. CONCLUSIONS: This pilot study suggests that the DigiScope may be a useful screening tool for AMD.     

Annular fundus autofluorescence abnormality in a case of macular dystrophy

Purpose: To present a case of macular dystrophy with early changes in fundus autofluorescence. Methods: A 20-year-old woman with a recent loss of visual acuity and onset of photophobia was examined. Color vision and visual field testing, fluorescein angiography, full-field and multifocal electroretinograms as well as fundus autofluorescence were performed. Results: Best-corrected visual acuity was 20/100 (right eye) and 20/60 (left eye). There was a red-green color vision defect and a relative central scotoma in both eyes. Ophthalmoscopy and fluorescein angiography were essentially normal, the presence of a dark choroid was debatable. Full-field ERG responses were normal, but the multifocal ERG showed severely reduced responses in the macular region. Both eyes showed a slight circular parafoveolar increase of fundus autofluorescence. Conclusion: Besides multifocal ERG, fundus autofluorescence aids to objectively assess the manifestation of macular dystrophies but does not discern between different types in early stages.     

频域OCT对正常人和青光眼光感受器细胞层厚度的检测

背景青光眼以视网膜内层的神经节细胞丢失为主要病理特征,但其是否累及视网膜外层尚有争议。部分研究认为青光眼将导致视网膜外层（光感受器）功能的异常,而病理学研究得出了不同的结论。目的用频域OCT测量正常人和青光眼患者光感受器细胞层的厚度,探讨青光眼对光感受器细胞层厚度的影响。方法采用病例对照研究。用频域OCT（SDOCT）对正常人38例38眼和青光眼患者48例48眼的黄斑区进行扫描,由一位检测者采用Sigma图像分析软件盲法测量黄斑中心凹和旁中心凹处（中心凹外1．5mm）视网膜光感受器层的厚度。同时采用时域OCT（Stratus OCT）测量所有检测眼的视盘周围视网膜神经纤维层（RNFL）厚度,比较正常组和青光眼组光感受器细胞核层的平均厚度,分析光感受器细胞层厚度与RNFL厚度的关系。结果正常组和青光眼组在黄斑中心凹光感受器细胞核层厚度分别是（96．7±10．7）μm、（103．7±13．3）μm,差异有统计学意义（P=0．011）;中心凹光感受器内节和外节层厚度分别是（59．3±5．5）μm、（59．5±5．5）μm,差异无统计学意义（P=0．890）。正常组和青光眼组在中心凹外3mm处光感受器细胞核层厚度分别是（70．9±14．0）μm、（68．7±10．7）μm,光感受器内节和外节层厚度分别为（45．2±6．4）μm,（43．6±5．5）μm,差异均无统计学意义（P=0．410,P=0．228）。黄斑中心凹处光感受器细胞核层厚度和RNFL厚度两者有二元线性关系（γ=-0．019X。＋2．73X＋10．34,R^2=0．211,P=0．005）。结论青光眼的黄斑中心凹光感受器细胞核层显著增厚,并随病程的变化而改变。     

Spectral- and time-domain optical coherence tomography measurements of macular thickness in normal eyes and in eyes with diabetic macular edema

Purpose

To report macular thickness values in normal eyes and eyes with diabetic macular edema (DME) using time-domain (TD) and spectral-domain (SD) optical coherence tomography (OCT), and to derive a conversion equation.

Methods

The index study was a prospective investigation conducted on 80 eyes from 40 normal subjects and 130 eyes from 118 patients with DME seen in our clinic. Retinal thickness values from the central 1 mm of the macula and surrounding four ETDRS subfields were acquired using TD-OCT (Stratus OCT) and SD-OCT (SPECTRALIS HRA+OCT). Measurements of the central (C) subfield from both devices were used to derive a conversion equation. The equation was used to predict SD-OCT values using measurements from TD-OCT. Agreement between predicted and actual SD-OCT measurements was assessed.

Results

In normal eyes, the mean difference between TD-OCT and SD-OCT measurements of the C subfield was 76 μm (CI₉₅=74 and 77, respectively). The conversion equation, y=1.029x+72.49, was derived. In eyes with DME, using the equation, SPECTRALIS-predicted values were 5% higher than actual measurements, with 95% of predicted values falling within 9% of the actual measurements. Relocating SD-OCT grids to match the location on TD-OCT resulted in predicted values falling within 7% of actual measurements.

Conclusions

The percent difference between actual thickness measurements from SPECTRALIS and predicted thickness measurements, using the conversion equation, was within reported limits of repeatability of Stratus in eyes with DME. Our equation may help correlate OCT values from both devices in standard care and clinical trials for DME.     

Predictors for the progression of geographic atrophy in patients with age-related macular degeneration: fundus autofluorescence study with modified fundus camera

Purpose

We examined the association between abnormal fundus autofluorescence (FAF) features on images obtained by a modified fundus camera (mFC) and geographic atrophy (GA) progression in patients with age-related macular degeneration (AMD).

Methods

Serial FAF images of 131 eyes from 131 patients with GA were included in the study. All FAF images were obtained with an mFC (excitation, ∼500–610 nm; emission, ∼675–715 nm). The GA area was quantified at baseline and 1 year later using a customized segmentation program. The yearly GA enlargement rate was then calculated. Abnormal FAF patterns in the junctional zone of GA were classified as None or Minimal change, Focal, Patchy, Banded, or Diffuse according to previously published classification based on confocal scanning laser ophthalmoscopy (cSLO). The relationship between GA enlargement and abnormal FAF was evaluated.

Results

The mean rate of GA enlargement was the fastest in eyes with Diffuse pattern (1.74 mm² per year), followed by eyes with the Banded pattern (1.69 mm² per year). Binary logistic regression analysis revealed that eyes with the Banded and Diffuse pattern had significantly higher risk for GA enlargement compared with eyes with the other patterns.

Conclusions

FAF image obtained by mFC appears to be acceptable for evaluating GA in accordance with an established cSLO-based classification. Eyes with the Banded or the Diffuse patterns of abnormal FAF at baseline indicate a high risk for GA progression. Identifying patients at high risk for GA progression using an mFC is broadly available method that can provide additional information to help predict disease course.     

Multimodal imaging of linear lesions in the fundus of pathologic myopic eyes with macular lesions

Graefe's Archive for Clinical and Experimental Ophthalmology - To detect, using multimodal imaging, lacquer cracks (LCs) and myopic stretch lines (MSLs) in pathologic myopic eyes with macular...     

Photoreceptor layer features in eyes with closed macular holes: optical coherence tomography findings and correlation with visual outcomes

PURPOSE: Study correlation between optical coherence tomography (OCT) findings and visual acuity (VA) outcomes after successful macular hole surgery (MHS). DESIGN: Retrospective cross-sectional study. METHODS: Postoperative OCT scans were analyzed in 34 eyes of 30 patients. Raw files of horizontal and vertical OCT scans were exported to Adobe Photoshop 7.0. Measured parameters included central foveal thickness, photoreceptor thickness, photoreceptor reflectivity, and relative reflectivity of photoreceptor to retinal pigment epithelium in the foveal area. Foveal configuration was subjectively graded. RESULTS: OCT scans were obtained at a median of 2 years (1 month to 10 years) postoperatively. The median visual acuity was 20/80 (20/50 to 8/200) preoperatively and 20/50 (20/20 to 5/200) postoperatively. The median foveal thickness was 198.5 micro (148 to 283). The mean (SD) photoreceptor layer thickness was 16.5 (8) micro in the 500 micro area and 17.5 (8) micro in the 1000 micro area. Mean (SD) of relative reflectivity of the photoreceptor layer was 0.60 (0.10) in both 500 micro and 1000 micro area. Postoperative VA did not correlate with foveal thickness or foveal configuration. Central (500 micro and 1000 micro) photoreceptor thickness was significantly correlated with final VA (r = .38, P = .026, each). Relative reflectivity of photoreceptors to retinal pigment epithelium in the 500 micro area was correlated with postoperative VA at a borderline significance (r = .32, P = .07). Relative reflectivity of photoreceptors to retinal pigment epithelium in the 1000 micro area was not significantly correlated with postoperative VA (r = .27, P = .12). CONCLUSION: Specific retinal features can be assessed from OCT images. Morphology and thickness of the foveal photoreceptor layer correlate well with macular function after successful MHS. Outer retinal features appear to be more important to determine postoperative visual function. Inner retinal features may be more relevant for the ophthalmoscopic appearance of anatomic closure.     

Comparison of time-domain OCT and fundus photographic assessments of retinal thickening in eyes with diabetic macular edema

PURPOSE: To explore the correlation between optical coherence tomography (OCT) and stereoscopic fundus photographs (FP) for the assessment of retinal thickening (RT) in diabetic macular edema (DME) within a clinical trial. METHODS: OCT, FP, and best corrected visual acuity (VA) measurements were obtained in both eyes of 263 participants in a trial comparing two photocoagulation techniques for DME. Correlation coefficients (r) were calculated comparing RT measured by OCT, RT estimated from FP, and VA. Principal variables were central subfield retinal thickness (CSRT) obtained from the OCT fast macular map and DME severity assessed by a reading center using a seven-step photographic scale combining the area of thickened retina within 1 disc diameter of the foveal center and thickening at the center. RESULTS: Medians (quartiles) for retinal thickness within the center subfield by OCT at baseline increased from 236 (214, 264) microm in the lowest level of the photographic scale to 517 (455, 598) microm in the highest level (r = 0.67). However, CSRT interquartile ranges were broad and overlapping between FP scale levels, and there were many outliers. Correlations between either modality and VA were weaker (r = 0.57 for CSRT, and r = 0.47 for the FP scale). OCT appeared to be more reproducible and more sensitive to change in RT between baseline and 1 year than was FP. CONCLUSIONS: There was a moderate correlation between OCT and FP assessments of RT in patients with DME and slightly less correlation of either measure with VA. OCT and FP provide complementary information but neither is a reliable surrogate for VA.     

自适应光学矫正LASIK术后眼高阶像差对视觉质量的影响

目的分析准分子激光原位角膜磨镶术（LASIK）术后医源性高阶像差对成像质量及视功能的影响。方法利用白适应光学系统,对LASIK术后有视觉症状的12例患者进行像差矫正。在暗室内,采用5g／L新福林滴眼液右眼散瞳后,实施6mm瞳孔下像差矫正,测定100％对比度视力,计算不同像差矫正策略下的调制传递函数曲线和点扩散函数。结果与静态结果相比,受试者眼凋制传递函数曲线和点扩散函数逐步提高,100％对比度视力也表现出类似的趋势。在矫正低阶像差的基础上,进一步矫正三阶像差使视力提高0．079LogMAR单位（P=0．016）。结论矫正医源性高阶像差可获得大瞳孔或暗环境下光学质量和高对比度视力的逐步提高,三阶像差对视觉质量的影响较大。     

相干光断层扫描测量正常人和青光眼患者黄斑厚度

目的 探讨相干光断层成像(optical coherence tomography,OCT)测量黄斑厚度对青光眼的诊断价值.设计 前瞻性对照研究.研究对象 62例(101眼)正常人和41例(64眼)青光眼患者.方法 应用Stratus OCT测量正常人和青光眼患者的黄斑厚度,观察正常人和青光眼患者的黄斑厚度地形图的图像特征;将正常人和青光眼患者黄斑厚度进行比较;用受试者工作特征曲线下面积(area under the receive operator characteristic curve,AROC)的分析方法找出青光眼早期诊断的最佳指标.主要指标 黄斑厚度地形图特征及各分区黄斑厚度、AROC.结果 正常人黄斑厚度地形图呈"马蹄形",青光眼患者的黄斑区视网膜呈局限性或弥漫性变薄.青光眼患者黄斑各分区视网膜厚度均比正常人减少,差异有统计学意义(P＜0.05),而早期青光眼患者仅黄斑外环各分区较正常人减少,差异有统计学意义(P＜0.05).无论是正常人和青光眼患者之间还是正常人和早期青光眼患者之间,黄斑下方外环区的AROC均最大(分别为0.876、0.728).结论 OCT测量正常人黄斑厚度地形图呈"马蹄形",青光眼患者黄斑厚度呈局限性或弥漫性变薄,黄斑下方外环区改变是较佳的早期诊断指标.(眼科,2008,17:25-28)     

RDH5 gene mutations and electroretinogram in fundus albipunctatus with or without macular dystrophy: RDH5 mutations and ERG in fundus albipunctatus

The aim of this study was to analyze the RDH5 gene in patients with fundus albipunctatus with and without macular dystrophy, and correlate the identified mutations with the electrophysiological results. Twenty-one patients from 19 unrelated Japanese families with fundus albipunctatus were examined. Ten unrelated patients had macular dystrophy. In 18 patients, either a homozygous or a compound heterozygous mutation in the RDH5 gene was identified. The bright-flash, mixed rod-cone ERG had a negative configuration with reduced a-wave amplitudes after a short period of dark-adaptation (20 or 30 min). After a prolonged dark-adaptation period (2 or 3 h), the waveform attained normal amplitudes in patients without macular dystrophy but the a-waves were still subnormal in patients with macular dystrophy. The photopic ERG responses were significantly reduced in patients with macular dystrophy, indicating that they also had cone dystrophy. The photopic ERGs were reduced in only some of the patients without macular dystrophy. In patients without macular dystrophy, the scotopic b-wave amplitudes were nonrecordable or significantly reduced after a short dark-adaptation period but then improved to normal levels. However, they did not fully recover in some patients with macular dystrophy. Three patients with macular dystrophy in whom a RDH5 gene mutation could not be detected by our routine method had atypical ERG responses. We conclude that RDH5 gene mutations cause a progressive cone dystrophy or macular dystrophy as well as night blindness. The clinical phenotype including electrophysiological responses varied among patients with the RDH5 gene mutations.