色觉的分子生物学研究

本文对人类正常色觉、红－绿色觉异常、蓝色觉异常、蓝锥细胞单色视的分子生物学研究进展进行介绍。叙述了各种色觉类型基因型的特点、多态性及变异的可能机制。     

色觉的分子生物学研究

本文对人类正常色觉，红－绿色觉异常、蓝色觉异常、蓝锥细胞单色视的分子生物学研究进展进行介绍。叙述了各种色觉类型基因型的特点，多态性及变异的可能机制。     

聚合酶链反应与分子杂交检测异常色觉基因的比较研究

根据色觉基因异常的特点，我们设计了一对２０个核苷酸长的引物以控制扩增红与绿色觉基因的第５个外显子。利用红与绿色觉基因第５个外显子酶切位点的差异对扩增ＤＮＡ片段进行酶解后电泳观察，以确定红或绿色觉基因异常的情况。并用色觉基因第４个内含子作为探针，以分子杂交法检测红与绿色觉基因第５个外显子相关片段的异常情况，两种方法结果一致。聚合酶链反应是一种简便、可靠、实用的异常色觉基因检出方法。     

黄斑光敏度联合色觉检查在青光眼检测中的应用

目的 为青光眼早期诊断寻求新的检测方法。方法 对开角型青光眼５４眼、可疑青光眼３４例,分别进行１０度视野的黄斑光阈值及ＦＭ１００－ｈｕｅ色觉测试法检查。结果 青光眼及可疑青光眼平均视野缺损与色觉总错误分均明显相关;但青光眼蓝与绿色觉异常率之间没有显著性差异,而可疑青光眼蓝与红绿及全色觉异常率之间具有显著性差异。结论 中心１０度视野内蓝锥细胞光敏度的变化,能早期反映青光眼视功能损害。     

Leber先天性黑蒙一例报告

Ｌｅｂｅｒ先天性黑蒙一例报告张雅红，周以浙，崔模Ｌｅｂｅｒ先天性黑蒙眼病是１８６９年Ｌｅｂｅｒ氏首先描述的，又称为先天性黑蒙，Ｌｅｂｅｒ视网膜毯层营养不良综合征，视网膜神经上皮发育不全。本病开始时眼底正常，容易漏诊或误诊，现报告一例。患儿女性，７岁，...     

不同色觉状态者对单色视标的调节反应研究

目的 探讨不同色觉状态者对不同颜色调节刺激的调节反应以及色觉机制在不同色觉状态者调节控制中的作用.方法 病例-对照研究.87名受试者,其中包括17名红色觉异常,47名绿色觉异常和23名色觉正常者,平均年龄(20.0±4.4)岁,测试视标为红-黑或绿-黑的等亮度垂直方波视标(空间频率3周/度,对比度0.9),通过Badal系统改变调节刺激水平(0.00 ～5.00 D).采用开放视野的红外自动电脑验光仪测量调节反应.不同色觉组之间的比较及不同调节刺激水平之间的比较采用单因素方差分析,两两比较采用LSD检验.红-绿视标的比较采用配对t检验.结果 红-黑视标测试,调节刺激4.00D时,红色觉异常组(AR=1.98 D)较色觉正常组(AR =2.55 D)调节反应低(P =0.031).当调节刺激为3.00、4.00、5.00D时,绿色觉异常组的调节反应分别为1.23、1.89、2.40 D,均低于色觉正常组(P＜0.05).绿-黑视标测试,当调节刺激为3.00和4.00D时,红色觉异常组调节反应分别为1.13、1.80 D,均较色觉正常组低(P＜0.05);当调节刺激为3.00、4.00、5.00D时,绿色觉异常组的调节反应分别为1.21、1.65、2.36 D,均低于色觉正常组(P＜0.05).红、绿色觉异常组对两种颜色各个刺激水平下的调节反应差异均无统计学意义.不同颜色视标对调节的影响:当调节刺激分别为2.00、3.00、5.00D时,红色觉异常组对红色视标的调节反应优于绿色视标(t=-2.81,-4.55,-3.15;P＜0.05).绿色觉异常只在调节刺激为4.00D时,对红色视标的调节反应优于绿色视标(t=-2.19,P＜0.05).当调节刺激分别为2.00、4.00、5.00D时,色觉正常组对红色视标的调节反应优于绿色视标(t=-2.57,-2.67,-2.15;P＜0.05).结论 色觉异常者的调节滞后量较色觉正常者大,证明色觉机制参与调节的控制.色觉各组受试者均表现为对红色视标的反应优于绿色视标或对红/绿视标反应无差异,这可能与长波长光对调节和正视化的影响有关.     

原发性开角型青光眼的客观色觉测定

评估等亮度颜色图像翻转视诱发电位作为一种客观色觉检查在原发性开角型青光眼所致的后天性色觉障碍的临床意义。方法对３１眼原发性开角型青光眼和３３眼正常对照测定ＣＰＲ－ＶＥＰ，包括白／黑、红／黑、绿／黑、蓝／黑、红／绿和蓝／黄７种颜色棋盘格。所有量者同时作ＦＭ１００－ｈｕｅ试验。     

先天性色觉异常患者的彩色视觉诱发电位改变

目的：初步探讨彩色视觉诱发电位（visual evoked potential,VEP)检查在临床应用的可行性,为临床诊断色觉异常提供新的方法。方法：应用计算机软件技术,制作4种翻转棋盘格作为视觉刺激模式,包括黑－白翻转棋盘格（对比度为95％）和等亮度红－白、绿－白和红－绿翻转棋盘格（饱和度为100％）。棋盘格大小为25’视角,翻转频率为0．8Hz。用多导程视觉电生理记录仪记录正常组30例色觉正常者和异常组13例先天性色觉异常者4种视觉刺激模式的瞬态VEP图形。结果：正常组4种视觉刺激模式VEPP1波潜伏期由短至长依次为红－白、黑－白、红－绿和绿－白,差异有非常显著意义（P＜0．01）;VEPP1波振幅由高至低依次为黑－白、红－白、红－绿、绿－白,差异有显著意义（P＜0．05）,其中红－白、红－绿、绿－白3种视觉刺激模式间VEPP1滤振幅比较,差异无显著意义（P＞0．05）。异常组VEPP1波潜伏期和振幅4种视觉刺激模式比较,差异均无显著意义（P＞0．05）,其中以黑－白翻转棋盘格刺激模式的潜伏期最短;红绿色盲和绿色盲患者对绿－白翻转棋盘格刺激无反应。正常组与异常组VEPP1波比较,4种视觉刺激模式的潜伏期差异均无显著意义（P＞0．05）;黑－白翻转棋盘格刺激模式的振幅差异无显著意义（P＞0．05）,红－白、绿－白和红－绿翻转棋盘格刺激模式的振幅差异有显著意义（P＜0．05）。结论：彩色VEP检查可为临床诊断色觉异常,尤其对于红绿色盲和绿色盲提供依据;目前彩色VEP检查尚缺乏定性和定量结果。     

隐匿性黄斑营养不良的多焦ERG

隐匿性黄斑营养不良 (ＯＭＤ)是少见的遗传性黄斑营养不良 ,其特点是眼底镜检查正常 ,眼底荧光血管造影、及全视野ＥＲＧ亦正常 ,但有进行性双眼视力下降。作者用多焦ＥＲＧ研究了ＯＭＤ患者视网膜后极部的局部功能。方法 :8例被确诊的ＯＭＤ患者均为正常眼底 ,正常眼底荧光血管造影 ,正常全视野ＥＲＧ ,Ｆ ＥＲＧ中心 1 0°(锥细胞ＥＲＧ)降低。与其年龄相匹配的正常对照者色觉、全视野ＥＲＧ正常 ,视力正常。两组随机选择一眼作多焦ＥＲＧ检查。多焦ＥＲＧ检查用ＶＥＲＩＳ系统进行 ,含 6 1个六边形刺激单元 ,帧频 75Ｈｚ,刺激单元面积随…     

百分制色觉定量检测表对正常人及先天性色觉异常者色觉感色力及辨色力的评估

目的 通过自行设计百分制色觉定量检测表(百分制量表)检查正常人及先天性色觉异常者色觉感色力和辨色力的差异。设计诊断技术评价。研究对象 采用俞自萍色盲本筛查色觉正常者48例(男性46例,女性2例);采用Farnsworth Munsell(FM-100)色相检测法确诊的红色觉异常者28例(男性27例,女性1例),绿色觉异常者71例(男性68例,女性3例)。方法 采用自制百分制量表检测受试者的色觉感色力和辨色力,并对评分进行对比分析,采用中位数(四分位数)描述。主要指标红色、绿色及蓝色感色力和红绿、红蓝及绿蓝辨色力百分制量表评分。结果 用百分制量表评价,正常人红色、绿色、蓝色感色力评分分别为96(95,97)、98(97,98)、95(92.25,96);红绿、红蓝、绿蓝辨色力评分分别为97(97,98)、96(95,97)、98(97,98)。与正常人相比,先天性红色觉异常患者的红色感色力[91.5(89.25,93)]、蓝色感色力[93(90,95)]和红蓝辨色力[90.50(86.25,92)]评分下降(Z=-6.837、-3.151、-6.780,P均<0.01);先天性绿色...     

Segmentation and accuracy in copying and drawing: Experts and beginners

As part of an ongoing investigation into real-world copying and drawing, I recorded the eye-hand drawing strategies of 16 subjects with drawing experiences ranging from expert to novice while they copied a line drawing of a standing nude. The experts produced accurate copies whereas all the beginners produced marked inaccuracies of overall scaling, proportion and shape. Analysis of eye and hand movements showed that the experts alone segmented the original drawing into simple line sections that were copied one at a time using a direct eye-hand strategy not requiring intermediary encoding to visual memory. The results suggest that segmentation into simple lines defines the task-specific process of accurate copying, and that this process is restricted to experts, i.e. acquired through training and practice. Additional preliminary tests also suggest that a similar process may apply to drawing a model from life.     

Proximal and accommodative convergence and age

The authors have estimated the phoria for distant and near fixation in two groups of subjects (mean age 27.5 ± 4.4 and 59.2 ± 8.2 years). Different accommodative stimuli were induced by adding minus lenses for distant fixation and plus lenses for near fixation. Statistical analysis of the experimental data indicates that, for distant fixation, the value of phoria per unit of accommodative stimulus is significantly lower in presbyopic than in nonpresbyopic subjects. Also, during near fixation, the accommodative convergence (AC/A ratio) is more reliable in the presbyopic subjects when the accommodative stimulus is progressively reduced. This varying behavior indicates in presbyopic subjects that proximal convergence is of greater relative importance in the determination of the fusion-free position. In nonpresbyopic subjects, accommodative convergence is the more important component.     

Anesthesia and preoperative and postoperative medications

Although certain methods such as retrobulbar blocks are used extensively, improvements in procedure can always be implemented. The use of ultrasound, low concentrations of anesthesia, careful monitoring, and, in the case of risk patients, anesthesia standby are all important considerations to ensure uneventful treatments. Topical anesthesia eliminates needle risk as well as risk of ptosis and bruising. Because it has been demonstrated that bacteria routinely enter the anterior chamber during uncomplicated cataract surgery, certain irrigation solutions are helpful, but still debatable. Postoperatively, diclofenac, flurbiprofen, and timolol have all been proven to be effective in reducing ocular inflammation, reducing incidence of CME, and controlling pressure increase, respectively.     

Paraneoplastic and non-paraneoplastic retinopathy and optic neuropathy: Evaluation and management

Paraneoplastic syndromes involving the visual system are a heterogeneous group of disorders occurring in the setting of systemic malignancy. Timely recognition of one of these entities can facilitate early detection and treatment of an unsuspected, underlying malignancy, sometimes months before it would have otherwise presented, and gives the patient an increased chance at survival. We outline the clinical features, pathogenesis, and treatment strategies for the retinal- and optic nerve–based paraneoplastic syndromes: cancer-associated retinopathy; melanoma-associated retinopathy; paraneoplastic vitelliform maculopathy; bilateral diffuse uveal melanocytic proliferation; paraneoplastic optic neuropathy; and polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome. Distinguishing these disorders from their non-paraneoplastic counterparts (e.g., autoimmune-related retinopathy and optic neuropathy, and acute zonal occult outer retinopathy) and determining appropriate systemic evaluation for the responsible tumor can be challenging. In addition, we discuss the utility and interpretation of autoantibody testing.     

Anesthesia and preoperative and postoperative medications

Retrobulbar blocks, although widely used, still have potentially serious complications. Topical anesthesia presents less risk of injury to the globe and less pain but requires careful usage and an experienced surgeon. New techniques, however, allow for an increase in the percentage of patients able to have topical anesthesia. Preoperatively, 2.5% phenylephrine is found to be just as effective as 10% phenylephrine, and, when compared with wound closure and surgeon's experience, the effect of prophylactic medications was found to be negated. Postoperatively, diclofenac is found to be as effective an anti-inflammatory agent as prednisolone. Also, the addition of 10% phenylephrine to 4% pilocarpine drops enhances the effectiveness of pharmacologic treatment of postoperative iridocorneal adhesions. In addition, ophthalmologists should be aware of emerging antibiotic resistance.     

Nodes and nodal points and lines in eyes and other optical systems

The typical stigmatic optical system has two nodal points: an incident nodal point and an emergent nodal point. A ray through the incident nodal point emerges from the system through the emergent nodal point with its direction unchanged. In the presence of astigmatism nodal points are not possible in most cases. Instead there are structures, called nodes in this paper, of which nodal points are special cases. Because of astigmatism most eyes do not have nodal points a fact with obvious implications for concepts, such as the visual axis, which are based on nodal points. In order to gain insight into the issues this paper develops a general theory of nodes which holds for optical systems in general, including eyes, and makes particular allowance for astigmatism and relative decentration of refracting elements in the system. Key concepts are the incident and emergent nodal characteristics of the optical system. They are represented by 2 × 2 matrices whose eigenstructures define the nature and longitudinal position of the nodes. If a system's nodal characteristic is a scalar matrix then the node is a nodal point. Otherwise there are several possibilities: Firstly, a node may take the form of a single nodal line. Second, a node may consist of two separated nodal lines reminiscent of the familiar interval of Sturm although the nodal lines are not necessarily orthogonal. Third, a node may have no obvious nodal line or point. In the second and third of these classes one can define mid-nodal ellipses. Astigmatic systems exist with nodal points and stigmatic systems exist with no nodal points. The nodal centre may serve as an approximation for a nodal point if the node is not a point. Examples in the Appendix , including a model eye, illustrate the several possibilities.     

Sensitivity to first- and second-order motion and form in children and adults

We compared the sensitivity of adults and children aged 3-10 years to first- and second-order motion and form. For first-order stimuli, at all ages sensitivity was better for motion than form, and motion thresholds were better at 6 Hz than at 1.5 Hz. For second-order stimuli, at all ages sensitivity was better for form than motion, and motion thresholds were better at 0.25 cyc/deg than at 1 cyc/deg. Thresholds became adult-like later for motion than for form and later for first-order than second-order stimuli. For first-order stimuli, the changes with age were larger and more protracted.     

Estrogen and progesterone receptors and human conjunctiva

Freshly frozen conjunctival tissue from premenopausal and postmenopausal women and male subjects were processed for estrogen and progesterone receptors by using monoclonal antibodies and a peroxidase-antiperoxidase technique. No immunocytochemical staining was localized in the nuclei of the cells treated with the monoclonal antibodies to human estrogen receptor or human progesterone receptor in any of the conjunctival specimens, in contrast to the strongly positive staining in breast adenocarcinoma controls. Immunocytochemical staining disclosed no evidence for estrogen or progesterone receptors on cells of the ocular surface.