糖尿病视网膜病变激光术后视野的改变

目的报告增殖性糖尿病视网膜病变(proliferative diabetic retinopathy PDR)、严重非增殖性糖尿病视网膜病变(severe nonproliferative diabetic retinopathy severe NPDR)、糖尿病性黄斑水肿患者激光治疗后视野的改变.方法52眼分A、B、C三组.A组为无黄斑水肿的PDR及严重NPDR,行全视网膜光凝术(panretinal photocoagulation PRP).B组为PDR合并黄斑水肿者,行PRP联合黄斑区光凝.C组为单纯黄斑水肿者,行黄斑区光凝.结果A组光凝后,30°内视野平均光阈值敏感度下降(P＜0.01),周边视野暗点增多或增大.B组光凝后,30°视野平均光阈值敏感度下降(P＜0.01),周边视野暗点增大增多,10°内光阈值敏感度下降(P＜0.05).C组10°内视野平均光阈值敏感度下降(P＜0.05).三组激光治疗前后视力无显著区别,新生血管明显消退,黄斑水肿消退.结论全视网膜光凝可有效阻止PDR的进一步发展,防止病人视力进一步下降,但降低了视网膜光敏感度,且周边部视野暗点增多.黄斑区光凝不损伤黄斑中心视功能,对糖尿病黄斑部病变局部代谢的改善,促进组织修复有一定临床意义.     

模糊适应对近视成人模糊阈值的影响

目的 研究近视成人对不同图片的模糊阈值在模糊适应前后的变化.方法 前瞻性自身对照研究.38例近视成人为实验组,屈光度-0.50～-6.00 D,散光度均＜-0.75 D,试镜架上放置等效球镜度数插片矫正至视力5.0以上.模糊阈值的测量由自主设计的电脑程序完成,依据double-staircase理论,随机呈现0～+2 D离焦量的3种图片(视力表E字母、Lena头像、街景图片).受检者在模糊适应前后均进行测量,判断图片“模糊”或“不模糊”.38例对象中有18例作为对照组隔天再次测量,测量方法一致但不进行模糊适应.数据采用重复测量方差分析处理.结果 ①对照组前后两次测量的模糊阈值差异无统计学意义.②实验组经模糊适应后模糊阈值降低,即模糊敏感性提高(E视标:F=5.883,P＜0.05;Lena:F=6.234,P＜0.05;街景图片:F=3.987,P＞0.05).③同一受检者在判断不同图片时的模糊阈值存在差异,Lena图像的阈值高于另2种图片(F=10.761,P＜0.01).结论 模糊适应能提高成人近视者对不同图片的模糊敏感性;模糊适应效应不只限于近视成人黄斑中心凹区;人眼对于不同图片的阈值存在显著差异.     

高度近视眼黄斑区视网膜厚度的相关因素分析

目的：探讨黄斑区视网膜厚度与屈光度、主导眼、眼轴长度的关系。 方法：入选高度近视组患者128例180眼,其中主导眼79眼,非主导眼101眼,应用OCT测量黄斑区及周围视网膜厚度及应用A超测量眼轴长度,另设正视眼组112人180眼,其中主导眼106眼,非主导眼74眼作为对照,获得数据进行统计学分析。 结果：高度近视患者的平均眼轴长度29.57依1.57 mm与正常组患者的平均眼轴长度（24.13依0.90mm）相比显著延长（P〈0.05）。眼轴长度与黄斑中心凹内环区（距黄斑中心凹1～3mm区）上方（ S1）、下方（ I1）、颞侧（ T1）及黄斑中心凹外环区（距黄斑中心凹3～6mm区）上方（ S2）、下方（I2）、鼻侧（N2）、颞侧（T2）视网膜厚度存在相关性,与黄斑中心区及黄斑中心凹内环区鼻侧（ N1）视网膜厚度无相关性。高度近视眼组黄斑中心区及各个分区均较正视眼组明显变薄（P〈0.05）。高度近视主导眼与非主导眼黄斑区视网膜厚度相比,无统计学意义（ P〉0.05）。 结论：高度近视患者黄斑区视网膜厚度OCT的检测值低于正视眼组。高度近视组眼轴长度与黄斑区上方（ S1）、下方（I1）、颞侧（T1）、上方（S2）、下方（I2）、鼻侧（N2）、颞侧（ T2）视网膜厚度存在负相关关系。高度近视眼中主导眼黄斑区视网膜厚度与非主导眼黄斑区视网膜厚度无差异性。     

视网膜大动脉瘤合并Coats病随诊3年一例

患者男性,56岁。因左眼视物模糊2个月于2005年9月就诊。既往高血压病史3年。视力：右眼1．0,左眼0．8。右眼底未见异常。左眼底：颞上视网膜动脉第三分支处可见1／6DD大小圆形扩张,其周围少量出血,黄斑区颞侧视网膜可见瘤样扩张,其周围散在黄白色渗出,未累及黄斑中心（图1A）,鼻下周边视网膜可见瘤样扩张。     

学龄期儿童黄斑区视网膜血流密度和厚度分析

目的观察并分析学龄期儿童黄斑区视网膜毛细血管血流密度和视网膜厚度与屈光度的相关性。方法横断面研究。2022年5～12月于郑州大学第一附属医院眼科就诊的学龄期儿童182名纳入研究。其中, 男性95名, 女性87名;年龄6～12岁;等效球镜度(SE)+0.50～-6.00 D。根据右眼SE将受检者分为正视眼组(+0.50≤SE<-0.50 D)、低度近视眼组(-0.50≤SE<-3.00 D)、中度近视眼组(-3.00≤SE≤-6.00 D), 分别为54、71、57例。采用扫频源光相干断层扫描血管成像仪对右眼黄斑区6 mm×6 mm范围进行扫描。软件自动将黄斑中心凹6 mm范围内视网膜划分为以黄斑中心凹为中心的3个同心圆, 分别为直径1 mm的中心凹区、1～3 mm的内环区、3～6 mm的外环区。测量黄斑区6 mm范围内不同分区视网膜浅层毛细血管丛(SVP)、深层毛细血管丛(DVP)血流密度和视网膜厚度。单因素线性回归、多重线性回归、平滑曲线拟合、阈值效应分析黄斑不同分区SVP、DVP、视网膜厚度与屈光度的相关性。结果正视眼组、低度近视眼组、中度近视眼组受检眼中心凹区、内环区...     

急性特发性黄斑病变1例

0引言急性特发性黄斑病变（acute idiopathic maculopathy,AIM）是一组原因不明的黄斑区急性损害导致视力急剧下降,继之以视力逐渐恢复为特点的黄斑疾病。该病具有好发于青年人,多有流感样病史,单眼或双眼均可受累,黄斑区视网膜浆液性脱离,病变区视网膜色素上皮细胞或外层视网膜限局性增厚等特点。     

双眼视网膜劈裂伴黄斑板层裂孔

患者女性, 24岁。因双眼视物模糊和变形6 d, 于沧州市中心医院眼科就诊。眼部检查:裸眼视力右眼为0.1, 左眼为0.02;矫正视力右眼为0.6(-4.50 D), 左眼为0.3(-3.25 D);双眼前节未见异常。超广角彩色眼底图像示双眼底后极部视网膜呈薄纱样改变, 周边视网膜可见界限相对清楚的环形;炫彩眼底图像示双眼黄斑区劈裂呈放射状类圆形;相干光层析成像术检查情况见精粹图片1;荧光素眼底血管造影术检查示黄斑中心凹呈窗样荧光无渗漏。临床诊断:双眼视网膜劈裂伴黄斑板层裂孔。     

正常青少年黄斑区活体测量及分析

目的:应用视网膜厚度分析仪(RTA)对青少年正常眼黄斑区视网膜厚度进行测定,以确定国人参考值范围及正常地形图的特点。方法:对100眼经眼科检查确认的正常眼按同一方法进行黄斑区RTA图像采集,使用随机软件对其厚度进行测量,并按照青少年黄斑地形图特点,人工测量不同黄斑分区距中心小凹的跨度,计算黄斑不同分区的范围及视网膜厚度的平均值。对结果应用多元回归方法探讨年龄、性别、眼别对视网膜厚度的影响。结果:黄斑区可分为中心小凹区、中心凹区、旁中心凹区,中心小凹直径为428±165μm,中心凹平均直径为1356±277μm,旁中心区平均直径为1450±226μm;黄斑部视网膜平均厚度168±14.3μm,黄斑各部位测量所得数值为:中心小凹区为128±22μm,中心凹区为138±17.6μm,旁中心凹区为169±15μm,不同分区视网膜厚度有明显差异(P <0.05),年龄对中心凹区和中心小凹区平均厚度影响最大(P <0.05);不同性别、眼别对视网膜厚度无影响(P >0.05)。我国青少年不同分区视网膜平均厚度低于RTA软件的正常参考值,差异有显著性(P <0.01)。结论:RTA能够对活体视网膜厚度进行精确的量化测定,青少年黄斑区厚度测定值可作为我国正常青少年人群黄斑视网膜厚度的正常值参考。     

河北省永年县农村成年人群黄斑区视网膜厚度的流行病学研究：邯郸眼病研究

目的 探讨中国北方农村成年人群黄斑区视网膜厚度与性别、年龄及屈光状态的关系。设计 横断面研究。研究对象 2012-2013年“邯郸眼病研究”河北省永年县人群5394名，平均年龄（57.8±11.2）岁。方法 对所有受试者进行问卷调查、详细的眼科检查及全身系统检查。采用相干光断层扫描（optic coherence tomography，OCT）并利用内置软件根据黄斑区视网膜厚度分为九个区（黄斑中心区、内环上方、内环下方、内环鼻侧、内环颞侧、外环上方、外环下方、外环鼻侧、外环颞侧）测量视网膜厚度。主要指标 黄斑区视网膜厚度。结果 5394名受试者中4735名（87.8%）OCT结果符合纳入标准。黄斑中心区、内环区、外环区平均视网膜厚度分别为（237.73±22.67） μm、（310.26±18.47） μm、（278.36±22.26） μm。男性及女性黄斑厚度分别为中心区（242.40±22.32） μm、（234.03±18.47） μm，内环平均厚度（314.82±18.39） μm、（306.64±17.72） μm，外环平均厚度（280.37±14.33） μm、（276.76±14.40） μm，各区存在明显差异（P均<0.001），且女性视网膜较男性薄。不同年龄组黄斑中心区视网膜厚度与年龄呈非单调曲线关系，约60岁为厚度最大值（P<0.001）。内环区与外环区黄斑视网膜厚度与年龄显著相关，随年龄增长而逐渐变薄（P<0.001）。屈光度与黄斑视网膜厚度存在关联，黄斑中心区、内环区、外环区屈光度每增加1.00 D，对应黄斑厚度改变分别为（-0.6±0.2） μm、（0.2±0.1） μm、（0.5±0.1） μm。结论 河北永年县农村成年人群中，黄斑区视网膜厚度随年龄增长而下降，且不同年龄段视网膜厚度的变化率不同。女性黄斑区视网膜厚度较男性薄。黄斑中心区视网膜厚度随近视屈光度的增加而变薄，而在外环区，视网膜厚度随近视屈光度的增加而增厚。     

应用三维光学相干断层成像术测量正常人黄斑视网膜厚度

目的 利用三维光学相干断层成像术(3D optical coherence Tomography 3D-OCT)测量正常人黄斑区视网膜厚度,观察其与性别的相关性.方法 依据早期糖尿病视网膜病变研究组(Early Treatment Diabetic Retinopathy Study ETDRS)9分区,应用3D扫描测量226名6个年龄组正常人黄斑区视网膜厚度地形图并进行统计学分析.结果 正常人黄斑中心凹平均视网膜厚度为(220±14)μm,其中男性(225±13) μm与女性(214±12)μm的差异具有统计学意义(P＜0.05).内环(1～3 mm直径区域即黄斑中心区)内鼻侧扇形区N1区平均视网膜厚度为(303±13) μm,上方扇形区S1区平均视网膜厚度为(300±11) μm,下方扇形区I1区平均视网膜厚度为(295±13) μm,颞侧扇形区T1区平均视网膜厚度为(289±12) μm.外环(3～6 mm直径区域内)鼻侧扇形区N2区平均视网膜厚度为(284±14) μm,上方扇形区S2区平均视网膜厚度为(267±12) μm,下方扇形区I2区平均视网膜厚度为(258±12) μm,颞侧扇形区T2区平均视网膜厚度为(257±11) μm.内环和外环男女差异均具有统计学意义(P＜0.05).结论 正常人经3D-OCT测得的黄斑区视网膜厚度男女之间差异具有统计学意义,在分析黄斑视网膜厚度时应考虑性别差异.     

Depth-of-focus of the human eye in the near retinal periphery

Although the depth-of-focus in the foveal region has been well investigated, knowledge regarding the effect of retinal eccentricity on blur detection and sensitivity is limited. In the present study, the depth-of-focus at the fovea and in the near retinal periphery (0 degrees -8 degrees ) was assessed psychophysically in 7 human subjects using a 5 mm artificial pupil with accommodation paralyzed. The group mean total depth-of-focus progressively increased linearly from 0.89 D at the fovea to 3.51 D at a retinal eccentricity of 8 degrees at the rate of 0.29 D/degree, with response variability (S.E.M.) remaining relatively constant (+/-0.17 D). We speculate that the reduced detection and sensitivity to blur in the near periphery may be attributed to retinal topography, sharpness overconstancy, optical aberrations, and visual attention in peripheral vision.     

Equiblur zones at the fovea and near retinal periphery

Knowledge regarding successive blur discrimination thresholds (i.e., equiblur zones) in depth and across the near retinal periphery, and their relation to blur detection (i.e., depth-of-focus), remains unknown. The blur detection threshold and four successive blur discrimination thresholds were measured psychophysically at the fovea, as well as at retinal eccentricities of 0.25 degrees , 2 degrees , 4 degrees , and 8 degrees . A Badal optometer system was used to assess blur sensitivity monocularly in five visually normal young adults with cycloplegia. The foveal test stimulus consisted of a small irregularly shaped black form, and the peripheral test stimulus consisted of high contrast circular apertures of different radii. Both the group mean blur detection and successive blur discrimination thresholds progressively increased with retinal eccentricity. At retinal eccentricities of 0 degrees , 0.25 degrees , 2 degrees , 4 degrees , and 8 degrees , the group mean blur detection thresholds were 0.53+/-0.06 D, 0.59+/-0.10 D, 0.93+/-0.11 D, 0.98+/-0.16D, and 1.25+/-0.25 D, while the average values of the group mean blur discrimination thresholds across the steps were 0.29+/-0.01 D, 0.37+/-0.01 D, 0.48+/-0.00 D, 0.51+/-0.01 D, and 0.72+/-0.02 D, respectively. At each retinal eccentricity, the blur discrimination thresholds were similar to each other, and they were approximately 60% of the blur detection threshold magnitude. These findings provide a conceptual representation of blur perception throughout the central visual field. Possible mechanisms are proposed for the decreased blur sensitivity in the near retinal periphery, as well as for the difference between the blur detection and blur discrimination thresholds.     

Blur discrimination of the human eye in the near retinal periphery.

BACKGROUND: Although blur discrimination in the foveal region has been investigated, knowledge regarding the effect of retinal eccentricity is limited. METHODS: The initial blur discrimination threshold and the blur detection threshold were assessed psychophysically and compared at the fovea and in the near retinal periphery (up to 8 degrees) with accommodation paralyzed. RESULTS: The blur discrimination and blur detection thresholds increased progressively with retinal eccentricity, with the latter being about twice as large and increasing twice as fast as the former. However, the group mean blur ratio between these two parameters remained relatively constant (0.56) with retinal eccentricity. CONCLUSIONS: The more sensitive blur discrimination vs. blur detection findings may be attributed to variation in the optical modulation transfer function with retinal defocus and to a perceptually based blur-buffering mechanism. The reduced blur sensitivity found with increased retinal eccentricity might be attributed to cone photoreceptor/ganglion cell sampling limitations, sharpness overconstancy, reduced visual attention, and slightly degraded visual optics.     

Foveal blur discrimination of the human eye

Although the effect of retinal defocus on the foveal blur detection threshold has been well investigated, knowledge regarding the foveal blur discrimination threshold is limited. In the present study, both thresholds were assessed psychophysically using the ascending method of limits at the fovea with accommodation paralyzed. The unidirectional blur detection threshold was 0.87+/-0.18 D (+/-1 S.E.M.). The subsequent blur discrimination thresholds were relatively constant and significantly smaller than the blur detection threshold, with an average value of 0.48+/-0.006 D (+/-1 S.E.M.). We speculate that the difference in magnitude between these two thresholds may be attributed to the defocus-related change in the ocular modulation transfer function (MTF) and its interaction with contrast discrimination ability, as well as to the presence of a neuroperceptual blur buffering mechanism.     

Central and near peripheral retinal contributions to the depth-of-focus using naturalistic stimulation

Although the depth-of-focus (DOF) has been investigated separately in the central retina and in the near retinal periphery, knowledge about their combined relative contribution to overall blur perception has remained unknown. In the present study, the DOF was measured psychophysically with a naturalistic pictorial stimulus as a function of spatial extent across the near retinal periphery under monocular Badal viewing conditions with accommodation paralyzed. The group mean total DOF progressively increased linearly with target size. Based on the individual DOF responses, the group was categorized into two subgroups: a predominantly centrally-driven and a centrally plus peripherally-driven subgroup. The results implicated partial cone pooling of blur information, as well as influence from perceptual, attentional, and optical aspects. However, the subgroup response profiles suggested individual differences in the weighting of the near peripheral blur information at the retinal level, and perhaps at higher-level areas of the visual system, involving spatial integration and global attentional processing.     

Retinal Responses to Simulated Optical Blur Using a Novel Dead Leaves ERG Stimulus

PurposeThe purpose of this study was to evaluate retinal responses to different types and magnitudes of simulated optical blur presented at specific retinal eccentricities using naturalistic images.MethodsElectroretinograms (ERGs) were recorded from 27 adults using 30-degree dead leaves naturalistic images, digitally blurred with one of three types of optical blur (defocus, astigmatism, and spherical aberrations), and one of three magnitudes (0.1, 0.3, or 0.5 µm) of blur. Digitally computed blur was applied to the entire image, or on an area outside the central 6 degrees or 12 degrees of retinal eccentricity.ResultsERGs were significantly affected by blur type, magnitude, and retinal eccentricity. ERGs were differentially affected by defocus and spherical aberrations; however, astigmatism had no effect on the ERGs. When blur was applied only beyond the central 12 degrees eccentricity, the ERGs were unaffected. However, when blur was applied outside the central 6 degrees, the ERG responses were significantly reduced and were no different from the ERGs recorded with entirely blurred images.ConclusionsBlur type, magnitude, and location all affect the retinal responses. Our data indicate that the retinal area between 6 and 12 degrees eccentricity has the largest effect on the retinal responses to blur. In addition, certain optical blur types appear to have a more detrimental effect on the ERGs than others. These results cannot be solely explained by changes to image contrast and spatial frequency content, suggesting that retinal neurons might be sensitive to spatial cues in order to differentiate between different blur types.     

Word acuity threshold as a function of contrast and retinal eccentricity.

BACKGROUND: We determined word acuity thresholds as a function of contrast and retinal eccentricity to determine the rate of threshold alteration in the normal retinal periphery. METHODS: Subjects identified words presented foveally (0 degrees eccentricity) or above the point of fixation at retinal eccentricities of 0.5, 1, 2, 3, 6, and 8 degrees for three contrast levels of 10, 45, and 85%. A descending method of limits was used to determine thresholds for random four-letter words flashed for 90 ms at the different retinal eccentricities. RESULTS: For high-contrast letters, word acuity displayed threshold elevation in the periphery similar to previous reports and similar threshold elevation to those reported for vernier acuity. Lower contrast levels displayed different threshold change as a function of eccentricity, approaching levels reported for grating acuity. When comparing the relative elevation of word acuity thresholds for the different contrast levels (85 vs. 45% and 85 vs. 10%), both comparisons showed that the most rapid decline in word acuity threshold occurs within 2 degrees of the fovea. CONCLUSIONS: The peripheral retina displays a reduction in word acuity threshold that is dependent on letter contrast and shows a change similar to those reported for higher cortical functions such as vernier thresholds. The greatest word threshold elevation occurs within the central 2 degrees of the fovea.     

Equivalent intrinsic blur in spatial vision

We used Gaussian blurred stimuli to explore the effect of blur on three tasks: (i) 2-line “resolution”; (ii) line detection; and (iii) spatial interval discrimination, in both central and peripheral vision. The results of our experiments can be summarized as follows.

(i) 2-Line “resolution”: thresholds for pairs of unblurred, low contrast, stimuli are approx. 0.5min arc in the fovea. When the stimulus blur is small, it has little effect upon 2-line “resolution”; however, when the stimulus blur, σ, exceeds 0.5 min, thresholds are degraded. We operationally define this transition point as the equivalent intrinsic blur or B_i. When the standard deviation of the stimulus blur, σ, is greater than B_i, then the “ resolution” threshold is approximately equal to σ. Both the unblurred “resolution” threshold, and the equivalent intrinsic blur, B_i, vary with eccentricity in a manner consistent with the variation of cone separation within the central 10 deg. When the stimulus blur exceeds the equivalent intrinsic blur, “resolution” in the periphery is the same as in the fovea.

(ii) Line detection: when the standard deviation of the stimulus blur, σ, is less than B_i, then the line detection threshold is approximately inversely proportional to σ (it is≈ T_dB_i/gs) i.e. it obeys Ricco's law. When the standard deviation of the stimulus blur, σ, is greater than B_i, then the “resolution” threshold is approximately equal to σ and the detection threshold is approximately a fixed contrast (to be referred to as T_d).

According to (i) and (ii), the equivalent intrinsic blur, B_i, plays a dual role in determining both the “resolution” threshold and the detection threshold, B_i corresponds to the “Ricco's diameter” for spatial summation in a detection task, and it also corresponds to the “resolution” threshold for thin lines. This connection between detection and “resolution” is somewhat surprising.

(iii) Spatial interval discrimination: thresholds are proportional to the separation of the lines (i.e. Weber's law). At the optimal separation, the thresholds represent a “hyperacuity” (i.e. they are smaller than the “resolution” threshold). For unblurred lines, the optimal separation is approximately 2–3 times the “resolution” limit at all eccentricities, so the optimal separation varies with eccentricity at the same rate as the equivalent intrinsic blur, B_i. However, the optimal spatial interval threshold falls off with eccentricity about 3–4 times more rapidly, consistent with the rate of decline of other position acuity tasks. For Gaussian blurred lines, over a wide range of separations and eccentricities, spatial interval discrimination thresholds begin to rise when the stimulus blur exceeds between about⅓ and ½ the separation of the lines. The strong elevation of the optimal spatial interval discrimination threshold in the periphery cannot be predicted on the basis of detectability of the lines, “resolution”, or on the basis of the equivalent intrinsic blur. We hypothesize that the increased spatial interval discrimination thresholds are a consequence of position uncertainty, perhaps due to sparse spatial sampling in the periphery.

Conceptual model of human blur perception

An empirically based, conceptual model of human blur perception is presented. It incorporates the concepts of blur detection and blur discrimination in depth, and across the central and peripheral retina, in two- and three-dimensional visual space. Key aspects of the model are its dynamic nature, predictability regarding the blur-based depth-ordering of objects, patterns of retinal defocus with far and near viewing, and interactions related to retinal defocus between the central and peripheral retina. Furthermore, a two-dimensional schematic representation of the blur-free region during near viewing is depicted in dioptric space. This model has implications with respect to accommodative control, depth perception, and refractive error development and progression.