中老年DR严重程度与血清HbA1c、TNF-α水平的相关性分析

目的：探讨中老年糖尿病视网膜病变(diabetic retinopathy,DR)患者DR严重程度与血清HbA1c、TNF-α水平的相关性。

方法：选取200例糖尿病患者,其中单纯糖尿病患者(DM组)60例,糖尿病伴非增殖期视网膜病变组(NPDR组)80例和糖尿病伴增殖期视网膜病变组(PDR组)60例,并选取80例健康者作为正常对照组(NC组)。观察患者的体检指标,并检测患者的空腹血糖(fasting plasma glucose,FPG)、餐后2h血糖(2hPG)、血脂、血清糖化血红蛋白(HbA1c)、血清肿瘤坏死因子-α(tumor necrosis factor,TNF-α)及泪液TNF-α。

结果：(1)四组受试者的体质量指数(body mass index,BMI)、FPG、2hPG、总胆固醇(total cholesterol ,TC)、甘油三酯(trilycerides,TG)、高密度脂蛋白(high density lipoprotein,HDL-C)、低密度脂蛋白(low-density lipoprotein,LDL-C)等指标比较,差异均具有统计学意义(F=37.211、395.421、42.515、7.385、121.764、121.568、34.567,均P<0.05)。DM、NPDR、PDR三组患者的BMI、FPG、2hPG、TC、TG、HDL-C、LDL-C等指标水平均高于NC组,差异有统计学意义(P<0.05); NPDR组患者的BMI、FPG、2hPG、TC、TG、HDL-C、LDL-C等指标水平均高于PDR组,差异有统计学意义(P<0.05)。(2)四组受试者血清TNF-α、泪液TNF-α及血清HbA1c水平比较,差异均具有统计学意义(F=337.256、215.471、40.522,均P<0.05); DM、NPDR、PDR三组患者的血清TNF-α、泪液TNF-α和血清HbA1c水平均高于NC组,差异有统计学意义(P<0.05); NPDR、PDR两组患者的血清TNF-α、泪液TNF-α和血清HbA1c水平均高于DM组,差异有统计学意义(P<0.05); PDR组患者的血清TNF-α、泪液TNF-α及血清HbA1c水平均高于NPDR组,差异有统计学意义(P<0.05)。(3)泪液TNF - α与血清TNF - α呈正相关(r=0.289,P<0.01); 泪液TNF-α与血清 HbA1c呈正相关(r=0.375,P<0.01)。

结论：中老年DR患者泪液TNF-α水平高于正常人,且随着视网膜病变的加重,泪液TNF-α水平升高。泪液TNF-α与血清TNF-α、HbA1c呈正相关。     

糖尿病视网膜病变严重程度与角膜上皮基底神经丛变化间的相关性

目的：探讨糖尿病视网膜病变(DR)严重程度与角膜上皮基底神经丛(SNP)变化间的相关性。

方法：研究纳入我院2018-01/2021-05收治2型糖尿病(T2DM)患者132例132眼和年龄相关性白内障患者80例80眼,其中T2DM患者中包括非DR(NDR)患者52例52眼,非增生性DR(NPDR)患者40例40眼及增生性DR(PDR)患者40例40眼,分析一般资料和角膜激光扫描共焦显微镜检查资料,采用Spearman秩相关分析评价DR临床分期与神经纤维长度间相关性。

结果：四组性别和年龄比较均无差异(P>0.05); PDR组糖尿病病程显著长于NPDR组、NDR组(P<0.05); NPDR组糖尿病病程显著长于NDR组(P<0.05); 年龄相关性白内障组空腹血糖和糖化血红蛋白水平均显著低于其他三组(P<0.05); PDR组最佳矫正视力显著低于NPDR组、NDR组(均P<0.05); NPDR组最佳矫正视力显著低于NDR组(P<0.05); 年龄相关性白内障组神经纤维长度值均显著大于NDR组、NPDR组及PDR组(P<0.05); PDR组神经纤维长度值显著小于NPDR组(P<0.05); Spearman秩相关分析结果显示,DR分期与神经纤维长度间呈负相关(r_s=-0.347,P<0.001)。

结论：DR病情严重程度与角膜上皮基底神经丛变化间具有相关性,PDR患者神经纤维长度较NPDR显著缩短; PDR和NPDR均存在神经结构缺失,T2DM眼底病变治疗时注意对眼表病变情况评估及处理。     

RBP4在增生期糖尿病性视网膜病变患者玻璃体中的表达及临床意义

目的：探讨RBP4在增生期糖尿病性视网膜病变(proliferative diabetic retinopathy, PDR)炎症反应中的作用。

方法：收集2017-02/07在武汉大学人民医院眼科中心就诊患者65例66眼玻璃体标本, 其中PDR组23例,非增生期糖尿病性视网膜病变(nonproliferative diabetic retinopathy, NPDR)组16例,非糖尿病患者26 例作为对照组。各组患者人口基线特征相匹配,PDR组及NPDR组患者糖尿病病程、血糖水平及糖化血红蛋白水平差异均有统计学意义(P<0.05)。ELISA检测各组玻璃体标本中视黄醇结合蛋白4(RBP4)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)的浓度。应用单因素方差分析比较并分析各组玻璃体中RBP4、IL-6、TNF-α的浓度。采用Pearson相关分析法分析RBP4与IL-6的相关性。

结果：RBP4在PDR组、NPDR组、对照组中浓度分别为13.68±2.66、11.03±1.12、10.45±1.17μg/mL。IL-6在PDR组、NPDR组、对照组中浓度分别为56.0±10.27、20.92±5.77、10.26±1.91pg/mL。PDR组中RBP4、IL-6浓度明显高于对照组及NPDR组,3组间总体差异有统计学意义(F=12.135、161.167,P<0.01),NPDR组玻璃体中RBP4浓度与对照组RBP4浓度差异无统计学意义(P>0.05)。NPDR组玻璃体中IL-6浓度较对照组显著升高,差异具有统计学意义(P<0.05)。玻璃体中RBP4浓度与IL-6浓度成明显正相关(r=0.606,P=0.001)。

结论：RBP4可能参与糖尿病性视网膜病变增生期的炎症反应过程,为疾病的诊断与治疗提供新的思路。     

DR患者外周血趋化因子MIP-1α和MIP-1β水平变化的临床意义

目的：观察糖尿病视网膜病变患者外周血趋化因子巨噬细胞炎症蛋白-1α(macrophage inflammatory protein,MIP-1α)、MIP-1β水平变化,并分析其临床意义。

方法：选取佛山市第五人民医院和佛山市南海区第四人民医院收治的糖尿病无视网膜病变患者(DM组)、非增殖期糖尿病视网膜病变患者(NPDR组)和增殖期糖尿病视网膜病变患者(PDR组),各50例; 选取50例健康体检者作为对照组。观察不同组别患者外周血趋化因子MIP-1α、MIP-1β水平、血糖情况和细胞因子水平的差异,采用Pearson相关分析法分析糖尿病视网膜病变患者外周血趋化因子MIP-1α、MIP-1β水平与血糖和细胞因子水平的相关性。

结果：DM组患者的MIP-1α、MIP-1β和平均血糖(mean blood glucose,MBG)水平均高于对照组,差异有统计学意义(t=6.306、2.954、3.617,均P<0.05); DM组患者的胰岛素样生长因子-1(insulin like growth factor-1,IGF-1)、成纤维细胞生长因子-21(fibroblast growth factor-21,FGF-21)、血管内皮生长因子(VEGF)水平均高于对照组,差异有统计学意义(t=27.216、7.778、3.214,均P<0.05)。PDR组患者的MIP-1α、MIP-1β和MBG水平均高于NPDR组,差异有统计学意义(t=6.620、3.461、3.378,均P<0.05); PDR组患者的IGF-1、FGF-21、VEGF水平高于NPDR组,差异有统计学意义(t=10.260、12.611、4.108,均P<0.05)。糖尿病视网膜病变患者的MIP-1α、MIP-1β水平与MBG、IGF-1、FGF-21、VEGF水平呈正相关。

结论：增殖期糖尿病视网膜病变患者的MIP-1α、MIP-1β水平较高,且与血糖和细胞因子水平呈正相关。     

中性粒细胞及血小板与淋巴细胞比值与2型糖尿病视网膜病变相关性

目的：探讨中性粒细胞与淋巴细胞比值(NLR)、血小板与淋巴细胞比值(PLR)与2型糖尿病视网膜病变(DR)的相关性。

方法：选择2型糖尿病(DM)患者200例, 按眼底检查结果分为眼底正常组(n=100)、非增殖期视网膜病变组(NPDR, n=62)和增殖期视网膜病变组(PDR, n=38)。同时选取100例健康体检者作为正常对照(n=100)组; 测定中性粒细胞、淋巴细胞及血小板计数等相关指标。

结果： PDR组患者NLR值(2.54)高于对照组(1.81)、DM组(1.76)及NPDR组(1.85),差异有统计学意义(P<0.05),PDR组患者PLR值(126.18)高于DM组(111.64),差异有统计学意义(P<0.05)。Logistic回归分析显示,年龄(β=-0.047)是糖尿病视网膜病变的保护因素(P<0.05),病程(β=0.071)和收缩压(β=0.024)是危险因素(P<0.05),而NLR、PLR在回归分析中无统计学意义。

结论：NLR、PLR值在PDR组升高,但并非糖尿病视网膜病变发生的独立危险因素。     

IL-6基因启动子区-572C/G多态性与大理白族2型糖尿病视网膜病变的关系

目的：探讨IL-6基因启动子区-572C/G多态性与大理白族2型糖尿病(type diabetic mellitus,T2DM)视网膜病变(diabetic retinopathy,DR)人群的相关性及视网膜病变程度的关系。

方法：采用聚合酶链反应联合限制性片段长度多态性分析(polymerase chain reaction-restriction fragment polymorphisms assay,PCR-RFLP)技术及基因测序技术,在大理白族人群中对150例T2DM患者及100例健康对照者(CON组)的IL-6-572C/G位点基因多态性进行检测。150例T2DM患者中,NDR(未合并DR)组57例,NPDR(合并非增生性糖尿病视网膜病变)组77例,PDR(合并增生性糖尿病视网膜病变)组16例。比较各组间基因型及等位基因分布频率,同时收集临床生化指标,最终数据使用SPSS22.0统计软件进行统计学分析。

结果：IL-6基因-572C/G位点组间基因型及等位基因频率相比较,差异均具有统计学意义(P<0.05); 携带C等位基因的个体避免患T2DM的风险为G等位基因的1.182倍(95% CI：1.059～1.319,P=0.004); 携带G等位基因的T2DM患者并发DR的风险为C等位基因的1.667倍(95% CI：1.195～2.326,P=0.003),但基因型及等位基因频率在PDR组与NPDR组比较,差异均无统计学意义(P>0.05); T2DM、NPDR+PDR组与CON组在空腹血糖、甘油三酯、体质量指数比较均有统计学差异(P<0.05); NPDR组与PDR组相比只有空腹血糖比较差异有统计学意义(P<0.05); 合并高血压的个体患T2DM的风险为未患高血压的 3.730倍(95% CI：2.060～6.754,P=0.000),同时患DR的风险为3.997倍(95% CI：2.099～7.612,P=0.000); 不同基因型间临床生化指标比较均无统计学差异(P>0.05)。

结论：IL-6基因-572C/G基因多态性与大理白族T2DM及DR的易感性相关,但临床生化指标对此易感关联没有协同作用,G等位基因是DR和T2DM发病的危险因素,但在NPDR进展至PDR过程中无意义,C等位基因对于T2DM和DR的发病具有保护作用; 高血压、空腹血糖、甘油三酯、体质量指数促进T2DM和DR的发病,空腹血糖在DR病情进展中具有重要作用。     

糖尿病视网膜病变患者血清Lp-PLA2水平的影响因素分析

目的：探讨影响糖尿病视网膜病变(DR)患者血清脂蛋白相关磷脂酶A2(Lp-PLA2)水平的相关因素。

方法：选取2015-09/2017-09我院内分泌科收治的2型糖尿病患者174例为研究对象,根据眼底检查结果分为无糖尿病视网膜病变(NDR)组、非增生性糖尿病视网膜病变(NPDR)组及增生性糖尿病视网膜病变(PDR)组3组,收集并比较三组患者的年龄、性别、体质量指数(BMI)、血压、血糖、血脂、血管内皮生长因子(VEGF)、C反应蛋白(CRP)及Lp-PLA2水平等临床资料。

结果：三组患者的糖尿病病程、空腹血糖(FPG)、餐后2h血糖(2hPG)、糖化血红蛋白(HbA1c)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、VEGF、CRP、Lp-PLA2比较 ,差异均有统计学意义(P<0.05); NPDR组患者血清TG、TC、HDL-C及CRP水平与NDR组患者比较,差异均无统计学意义(P>0.05),而PDR组患者各项生化指标与NDR组患者比较,差异均有统计学意义(P<0.05); PDR组患者VEGF、CRP、Lp-PLA2均较NPDR组患者显著升高,差异均有统计学意义(P<0.05)。Pearson相关分析发现,血清Lp-PLA2与患者年龄、糖尿病病程、2hPG、TG、VEGF、CRP呈正相关; 回归分析发现,血清Lp-PLA2与糖尿病病程、血清VEGF水平呈显著正相关。

结论：DR患者血清Lp-PLA2水平显著升高,其水平与糖尿病病程、血清VEGF水平呈正相关,可作为DR诊断的参考指标。     

LncRNA HIF1A-AS1在增生性糖尿病视网膜病变中的表达及诊断价值

目的：探讨长链非编码RNA(LncRNA)缺氧诱导因子-1α-反义链1(HIF1A-AS1)在增生性糖尿病视网膜病变(PDR)患者血清中的表达情况及诊断价值。

方法：选取2019-07/2021-07本院收治的糖尿病视网膜病变(DR)患者160例,根据病变程度分为PDR组(80例)和非增生性糖尿病视网膜病变(NPDR)组(80例),同时选取本院100例健康体检者为对照组。检测并比较所有研究对象血清中甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、空腹血糖(FBG)、糖化血红蛋白(HbA1c)水平; 采用实时荧光定量PCR(qRT-PCR)法检测血清中LncRNA HIF1A-AS1表达水平; 通过Logistic回归分析影响PDR发生的危险因素; 利用受试者工作特征曲线(ROC)分析LncRNA HIF1A-AS1水平诊断PDR的临床价值。

结果：PDR组患者血清中LncRNA HIF1A-AS1表达水平明显高于NPDR组和对照组,NPDR组高于对照组(P<0.05); PDR组、NPDR组患者糖尿病病程、HbA1c、TC、TG、LDL-C、FBG水平显著高于对照组,PDR组HDL-C水平显著低于对照组(P<0.05); LncRNA HIF1A-AS1水平与糖尿病病程、HbA1c、TC、TG、LDL-C、FBG呈正相关(P<0.05),与HDL-C呈负相关(P<0.05)。Logistic回归分析结果显示,LncRNA HIF1A-AS1、病程、FBG、HbA1c、TC、TG、LDL-C均是PDR发生的危险因素(P<0.05)。ROC结果显示,LncRNA HIF1A-AS1水平预测PDR发生的曲线下面积(AUC)为0.766(95%CI：0.692～0.829),对应的敏感度为66.25%,特异度为78.75%。

结论：PDR患者血清中LncRNA HIF1A-AS1水平上调,是PDR发生的危险因素,且可作为预测PDR发生的潜在血清学指标。     

彩色多普勒超声对糖尿病眼球后血管血流动力学的研究

目的：探讨彩色多普勒超声对糖尿病眼球后血管血流动力学改变的作用。

方法：选取2010-06/2013-05我院收治的2型糖尿病眼病患者80例160眼作为研究组,通过眼底照相和直接检眼镜检查将研究组分为糖尿病无视网膜病变组(DNR组)、糖尿病视网膜病变非增殖期组(NPDR组)、糖尿病视网膜病变增殖期组(PDR组),选取同期眼部正常者60例120眼作为对照组,通过彩色多普勒超声对各组间视网膜中央动脉(CRA)、睫状后动脉(PCA)及眼动脉(OA)的多普勒血流参数指标进行分析。

结果：研究组与对照组在CRA、PCA和OA的血流参数上存在显著差异(P<0.05); DNR组、NPDR组和PDR组在CRA、PCA和OA的收缩期峰值流速(PSV)、舒张末期血流速度(EDV)、阻力指数(RI)与对照组存在显著差异(P<0.05),且PDR组与DNR组、NPDR组也存在显著差异(P<0.05)。

结论：通过彩色多普勒超声动态监测视网膜血流状态并对血流频谱形态进行分析,根据血流变化可以对DR病变程度进行判定,从而为治疗和预后提供参考价值。     

糖尿病视网膜病变患者血清CMKLR1水平及临床意义

目的：探讨糖尿病视网膜病变(DR)患者血清CMKLR1水平及临床意义。

方法：选取2015-02/2018-03在我院治疗的2型糖尿病(T2DM)患者140例,其中单纯T2DM患者45例,DR患者95例(NPDR患者54例,PDR患者41例),并纳入健康志愿者40例。收集临床资料并检测血清CMKLR1水平。

结果：PDR患者糖尿病病程长于NPDR和NDR患者,且NPDR患者长于NDR患者(均P<0.05)。T2DM患者FPG和血清TG水平升高,HDL-C水平降低,且DR患者LDL-C水平高于NDR患者和健康志愿者(均P<0.05)。PDR患者血清CMKLR1水平高于NPDR、T2DM患者和健康志愿者,且NPDR患者高于NDR患者和健康志愿者,NDR患者高于健康志愿者(均P<0.05)。DR患者血清CMKLR1水平与糖尿病病程、HbA1c和LDL-C呈正相关(r=0.374、0.248、0.304,均P<0.05),其中糖尿病病程和血清CMKLR1水平是DR发生的危险因素(OR=1.594、1.830,均P<0.05)。

结论：DR患者血清中CMKLR1水平升高,且与病情进展有关,是影响DR发生发展的重要危险因素。     

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.     

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.     

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.     

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.     

Ethics and optometry: concepts and applications

Ethics refers both to the study of behaviour, and moral principals. The related concepts of justice and law are also relevant to optometry. A profession typically claims specialist knowledge and ethical behaviour – putting the interests of clients above its own. However, professional codes fail as ethical directives, and their goals are questioned. Beginning with broad principles, institutional ethics and issues of general health care provision are considered, and applications to optometry are made. Ethical theory can guide us in interacting with our patients, utilising resources and ordering priorities. The conservative approach to consumerism and advertising is defended on the basis of protecting public and professional interests. Ethical behaviour can be fostered, and this process should begin in undergraduate education.     

Nutritional antioxidants and age-related cataract and maculopathy

Loss of vision is the second greatest, next to death, fear among the elderly. Age-related cataract (ARC) and maculopathy (ARM) are two major causes of blindness worldwide. There are several important reasons to study relationships between risk for ARC/ARM and nutrition: (1) because it is likely that the same nutritional practices that are associated with prolonged eye function will also be associated with delayed age-related compromises to other organs, and perhaps, aging in general, (2) surgical resources are insufficient to provide economic and safe surgeries for cataract and do not provide a cure for ARM, and (3) there will be considerable financial savings and improvements in quality of life if health rather than old age is extended, particularly given the rapidly growing elderly segment of our population. It is clear that oxidative stress is associated with compromises to the lens and retina. Recent literature indicates that antioxidants may ameliorate the risk for ARC and ARM. Given the association between oxidative damage and age-related eye debilities, it is not surprising that over 70 studies have attempted to relate antioxidant intake to risk for ARC and ARM. This article will review epidemiological literature about ARC and ARM with emphasis on roles for vitamins C and E and carotenoids. Since glycation and glycoxidation are major molecular insults which involve an oxidative stress component, we also review new literature that relates dietary carbohydrate intake to risk for ARC and ARM. To evaluate dietary effects as a whole, several studies have tried to relate dietary patterns to risk for ARC. We will also give some attention to this emerging research. While data from the observational studies generally support a protective role for antioxidants in foods or supplements, results from intervention trials are less encouraging with respect to limiting risk for ARC/ARM prevalence or progress through antioxidant supplementations, or maintaining higher levels of antioxidants either in diet or blood. Without more information it is difficult to parse these results. It would be worthwhile to determine why the various types of studies are not yielding similar results. However, there are many common insults and mechanistic compromises that are associated with aging, and proper nutrition early in life may address some of these compromises and provide for extended youthful function later in life. Indeed, proper nutrition, possibly including use of antioxidant supplements for the nutritionally impoverished, along with healthy life styles may provide the least costly and most practical means to delay ARC and ARM. Further studies should be devoted to identifying the most effective strategy to prevent or delay the development and progress of ARC/ARM. The efforts should include identifying the right nutrient(s), defining useful levels of the nutrient(s), and determining the age when the supplementation should begin.     

Exogenous attention and color perception: performance and appearance of saturation and hue

Exogenous covert attention is an automatic, transient form of attention that can be triggered by sudden changes in the periphery. Here we test for the effects of attention on color perception. We used the methodology developed by Carrasco, Ling, and Read [Carrasco, M., Ling, S., & Read, S. (2004). Attention alters appearance. Nature Neuroscience, 7 (3) 308-313] to explore the effects of exogenous attention on appearance of saturation (Experiment 1) and of hue (Experiment 2). We also tested orientation discrimination performance for single stimuli defined by saturation or hue (Experiment 3). The results indicate that attention increases apparent saturation, but does not change apparent hue, notwithstanding the fact that it improves orientation discrimination for both saturation and hue stimuli.     

Aberration and contrast sensitivity comparison of aspherical and monofocal and multifocal intraocular lens eyes

BACKGROUND: Higher-order aberrations and contrast sensitivity were evaluated in patients who underwent phacoemulsification cataract extraction followed by implantation of aspherical, monofocal or multifocal intraocular lens (IOL) replacements. METHODS: In this comparative trial, 124 patients with an average age of 66.8+/-5.2 years and their 124 eyes were randomly divided into three surgical implantation groups to receive one of three types of IOLs in replacement of cataract lenses. The patients of group 1 were given an aspherical IOL Z9001 (AMO, Santa Ana, CA, USA) replacement, and group 2 was implanted a monofocal IOL SA60AT (Alcon, Fort Worth, TX, USA) and group 3 the multifocal IOL SA40N (AMO). Post-surgical best-corrected visual acuity, corneal aberrations, total ocular aberrations, pupil diameters, capsulorhexsis sizes and contrast sensitivity were measured and compared. RESULTS: There was no statistical difference for mean best-corrected visual acuity, pupil diameter, curvilinear capsulorhexis size and corneal aberration among the three groups. For the spherical aberration, fourth-order higher-order aberration and total ocular higher-order aberration, the SA40N group was higher than the SA60AT group and the SA60AT group was higher than the Z9001 group, and the differences between the three groups were statistically significant for these measurements. Contrast sensitivity was higher for the Z9001 group than the SA60AT group and the SA60AT group was higher than the SA40N group, and the difference was statistically significant in all the spatial frequencies of 3, 6, 12 and 18. CONCLUSIONS: Although the multifocal IOL can provide near vision, it can increase higher-order aberration and negatively influence contrast sensitivity. However, the aspherical IOL can reduce aberration and improve contrast sensitivity as compared with the monofocal IOL.