近视患者明暗瞳孔下Kappa角的变化及分析

目的：研究近视患者双眼暗视至明视状态下Kappa角水平偏移量及垂直偏移量的变化规律。方法：横断面研究。选取2020年11月至2021年12月在宁夏医科大学总医院门诊近视中心明确诊断为近视的患者，并采用单纯随机抽样的方法抽取120例（240眼），采用博士伦Orbscan II角膜地形图仪分别于暗视及明视条件下进行检查，记录明暗视下瞳孔直径大小、Kappa角的大小及水平偏移量和垂直偏移量。采用配对t检验比较左右眼在暗视和明视下的瞳孔直径和Kappa角大小；采用散点分布图分析双眼在明暗视下Kappa角的象限分布。结果：左右眼在暗视状态下的瞳孔直径均明显大于明视状态下的瞳孔直径，差异有统计学意义（t=13.67，P<0.001；t=13.48，P<0.001）。暗视与明视状态下左眼的Kappa角均大于右眼的Kappa角，差异有统计学意义（t=4.15，P=0.021；t=5.27，P=0.008）。由暗视转向明视状态时，双眼Kappa角的分布呈现镜像对称，水平方向主要向鼻侧位移，垂直方向主要向上方位移。右眼矢量位移（0.168±0.100）mm，左眼矢量位移（0.171±0.069）mm；87.5%右眼矢量位移小于0.3 mm，92.5%左眼矢量位移小于0.3 mm，绝大多数近视患者的矢量位移在0.3 mm以内。结论：从暗视至明视状态下，随着瞳孔缩小，近视患者的Kappa角分布主要向鼻上方位移。     

Pentacam三维眼前节分析诊断系统 与Keratron Scout角膜像差仪测量 Kappa角的比较

目的：比较Pentacam三维眼前节分析诊断系统与Keratron Scout角膜像差仪测量屈光手术患者Kappa 角大小的差异。方法：系列病例研究。选取空军军医大学西京医院眼科屈光矫正中心术前筛查患 者98例（196眼）。在同一环境下进行Pentacam与Keratron Scout检查,记录2种检查方式的瞳孔直径、 Kappa角大小（采用直角坐标系表示）,从而获得Kappa角在角膜的x轴和y轴偏移量,比较2种检查方 法测量的Kappa角大小的差异及2种检查方法的相关性。采用配对t检验以及Pearson相关分析进行 数据处理。结果：Pentacam与Keratron Scout测量近视患者的瞳孔直径分别为右眼（3.17±0.44）mm、 （3.19±0.53）mm,左眼（3.25±0.65）mm、（3.33±0.48）mm,二者差异均无统计学意义。Pentacam与 Keratron Scout测得双眼的Kappa角x轴以及y轴偏移量的差异均无统计学意义,2种方法测得的Kappa 角偏移量具有显著相关性（P<0.05）,右眼x轴相关系数为0.966,y轴为0.969,左眼x轴为0.956,y轴 为0.913。结论：在瞳孔直径一致的条件下,Pentacam三维眼前节分析诊断系统与Keratron Scout角膜 像差仪测量近视以及近视散光患者Kappa角无差异,在手术设计中均可作为Kappa角调整的参考。     

明视、暗视及药物散瞳状态下的瞳孔位置

目的观察明视、暗视及药物散瞳状态下的瞳孔位置,评价瞳孔位置是否随瞳孔直径而改变及其与年龄、屈光不正等因素的相关性。方法运用Asc lep ion波前像差仪检测获得130例(130眼)屈光不正患者在明视、暗视及药物散瞳状态下的眼前节图像,设计软件计算图像中的瞳孔中心位置、角巩膜缘几何中心位置。结果随着瞳孔直径的增大,瞳孔中心位置始终向颞侧偏移。从明视到暗视,瞳孔直径平均由4.06 mm增至6.37 mm,而瞳孔中心平均向颞侧移动0.133 mm(t=4.604,P<0.01);从暗视到药物散瞳状态,瞳孔直径平均由6.37 mm增至7.58 mm,而瞳孔中心平均向颞上方移动0.162 mm(t=4.180,P<0.01);从明视到药物性散瞳,瞳孔中心平均向颞上方移动0.183 mm(t=7.378,P<0.01);但瞳孔中心位置的移动量与年龄、屈光不正度及瞳孔直径的改变值无显著相关性。结论瞳孔中心位置随着瞳孔直径的增大而主要向颞侧偏移同时略向上移动,但总的移动量不大。     

白内障患者Kappa角特点及明暗状态下的变化

目的 探讨Kappa角特点及明暗状态下的变化规律。方法 系列病例研究。选取2016年5月至2017年10月于厦门大学附属厦门眼科中心行白内障手术的患者394例（788眼）,采用OPD-Scan Ⅲ进行检查,搜集的数据包括患者的临床数据（年龄、性别、眼部病史及手术史）,及术前生物测量数据如平均角膜曲率（Mean K）、角膜球差（CSA）、白到白距离（WTW）、明视瞳孔直径（Photopic）、暗视瞳孔直径（Mesopic）,明视瞳孔时Kappa角的大小和位移角度（PDist@Angle）、暗视瞳孔时Kappa角的大小和位移角度（MDist@Angle）、暗视瞳孔中心相对于明视瞳孔中心位移的大小和角度（MPDist@Angle）等。数据采用秩和检验、卡方检验、多元回归统计分析处理。结果 双眼各生物测量因素对比中Mean K、MPDist、PDist、WTW、CSA差异无统计学意义（P>0.05）,而Photopic、Mesopic、MDist左右眼差异有统计学意义（Z=2.276、3.284、2.388,均P<0.05）。双眼明暗状态下均为正Kappa角占多数;双眼由明瞳向暗瞳转变时瞳孔中心多向颞下方位移。分别将双眼临床、生物测量数据与MPDist进行多元回归分析,右眼回归方程为：MPDist=0.033+0.505×MDist+0.041×CSA-0.319×PDist（F=45.0,P<0.001）,左眼回归方程为：MPDist=-0.002+0.547×MDist+0.013×Mesopic-0.350×PDist（F=61.6,P<0.001）。结论 白内障患者正Kappa角占多数;不同明暗度下瞳孔大小的改变会影响Kappa角的大小,而且明暗瞳孔大小及明暗交替时瞳孔中心的大小和位移角度在不同患者间存在较大差异;MPDist的变化与PDist、MDist、Mesopic、CSA存在线性回归关系,其中双眼MPDist均与PDist存在负相关,双眼MDist均对MPDist的变化影响相对较大。     

行FS-LASIK近视患者的Kappa角动态分布特征及其相关性分析

目的：探讨行飞秒激光联合准分子激光原位角膜磨镶术(FS-LASIK)近视患者的瞳孔大小和中心的动态变化分布, 角膜共轴反光点的偏心量分布规律及其相关性分析。

方法：本研究采用回顾性研究,选择2019-01/05在延边大学附属医院眼科行FS-LASIK的患者225例407眼,术前采用角膜地形图仪测量瞳孔的大小和中心位置,准分子激光机记录患者仰卧位时瞳孔中心与角膜共轴反光点之间的偏移量(P-Dist)。

结果：术前角膜中心与瞳孔中心之间的偏移量分布平均为0.322±0.194mm,262眼(64%)≤0.40mm; P-Dist分布平均为0.225±0.102mm,326眼(80%)≤0.30mm。角膜共轴反光点主要偏向角膜中心的颞上侧138眼(34%)。暗光条件下左眼X轴：-0.061±0.084mm,右眼X轴：-0.016±0.059mm(P=0.002)(左眼暗光下向颞侧位移)。角膜横径(WTW)与瞳孔直径变化呈正相关性(r=0.270, P<0.001)。

结论：左眼应调整切削中心偏向颞侧0.061mm以内的位置上,角膜横径偏大的患者,术中尽量维持较暗光线环境,以便提高瞳孔匹配的效率。     

LASIK术前瞳孔大小与术后夜间眩光的关系

目的探讨行双眼准分子激光原位角膜磨镶术(LASIK)者术前瞳孔大小与术后夜间眩光的关系。方法将240例(480眼)按近视屈光度分为2组:组Ⅰ(低、中度近视组)-1.00D~-6.00D;组Ⅱ(高度近视组)-6.25D~-12.50D。以TOPCON Auto Kerato_Refractometer KR-8100测定240例(480眼)近视眼术前暗环境中的瞳孔大小,分析所得数据。记录术前、术后的屈光度和最佳矫正视力(BCVA)。术后3月随访时,患者填写一份术后夜间眩光的问卷。结果双眼平均BCVA手术前后差异无统计学意义(P>0.05)。低、中度近视组平均暗视瞳孔直径(6.24±0.72)mm;高度近视组平均(7.33±0.41)mm,两组差异有统计学意义(P<0.01)。术后夜间眩光与术前暗环境中大的瞳孔明显相关(P<0.01)。术后夜间眩光与性别亦有显著相关性(P<0.05),男性术后夜间眩光发生率大于女性。结论LASIK术前暗环境中大的瞳孔与术后夜间眩光有关联。因此对行LASIK手术的近视患者应进行术前瞳孔大小的评估。     

Lenstar LS900测量仪与iTrace视觉功能分析仪测量白内障患者术前Kappa角与Alpha角一致性研究

目的比较Lenstar LS900测量仪与iTrace视觉功能分析仪测量年龄相关性白内障患者术前Kappa角与Alpha角的一致性。方法收集2017年12月至2018年6月在中国医科大学附属第四医院眼科就诊的年龄相关性白内障患者55例(59眼),术前分别应用Lenstar LS900测量仪和iTrace视觉功能分析仪测量以瞳孔为中心的视轴偏心距(Kappa角)和以虹膜为中心的视轴偏心距(Alpha角)。先收集在角膜顶点平面分解的X轴和Y轴坐标,再通过三角函数计算偏心距,最后分别比较X轴、Y轴、瞳孔直径、角膜水平直径、视轴偏心距。两种仪器所测数据的比较采用配对t检验,一致性比较采用Bland-Altman分析。结果 Lenstar LS900测量的Kappa角为(0.270±0.128)mm,Alpha角为(0.349±0.128)mm,瞳孔直径为(4.101±0.773)mm,角膜水平直径(白到白,WTW)为(10.848±0.467)mm,X轴Kappa角为(0.016±0.225)mm,Y轴Kappa角为(0.105±0.185)mm,X轴Alpha角为(0.010±0.353)m...     

Ⅱ型糖尿病患者瞳孔相关性自主神经病变的研究

目的探讨通过暗视、明视及药物散瞳3种状态下瞳孔直径对评价Ⅱ型糖尿病患者瞳孔源性自主神经病变的意义。方法选取我院内分泌科Ⅱ型糖尿病患者,根据荧光素钠眼底血管造影结果分为亚临床期组和单纯期组,随机各取20例,选取相应年龄段眼科就诊的非糖尿病的泪道病患者20例作为正常对照组,采用红外线数码摄影法拍摄暗视、明视及药物散瞳状态下的眼前节照片,获得瞳孔图片,通过计算机软件处理,换算出瞳孔直径及缩小率和散大率。将所得数据进行统计学分析。结果正常对照组、亚临床期组和单纯期组在暗视下的瞳孔直径分别为(6．02±0．48)、(5．87±0．99)、(4．95±1．12)mm;明视下分别为(3．40±0．33)、(3．37±0．31)、(3．25±0．47)mm;药物散瞳后分别为(7．37±0．59)、(6．91±1．00)、(5．49±1．24)mm;缩小率分别为(43±7)％、(41±10)％、(32±14)％;散大率分别为(23±8)％、(19±13)％、(11±5)％。暗视下和药物散瞳后的瞳孔直径及缩小率和散大率的组间差异有统计学意义(P<0．01)。结论Ⅱ型糖尿病患者早期即可出现瞳孔源性自主神经病变,暗视和药物散瞳状态下的瞳孔直径及缩小率和散大率可用于评价Ⅱ型糖尿病患者的自主神经病变。     

角膜屈光手术患者明暗瞳孔下Kappa角的变化及分析

目的：观察角膜屈光手术患者明暗瞳孔下Kappa角的大小及明暗瞳孔时Kappa角的变化规律。方法：选取近视手术患者118例234眼,采用 Keratron Scout角膜地形图仪分别于室内照明及暗室情况下进行检查,记录明暗瞳孔直径大小、明暗瞳孔时Kappa角的大小。结果：左右眼明暗瞳孔直径大小的差异有统计学意义（P＜0．01）。明瞳时,左右眼Kappa角鼻上方分布较多;暗瞳时,左右眼Kappa 角颞上分布较多。明暗瞳孔下, Kappa角的水平及垂直偏移的差异均有统计学意义（ P＜0．01）。结论：不同明暗度下瞳孔大小的改变会影响Kappa角的大小,这种变化可能对依据Kappa角进行居中设计的角膜屈光手术的准确性产生影响。     

近视眼飞秒激光小切口基质透镜取出术后角膜光学质量的客观评估

背景 目前评价飞秒激光小切口基质透镜取出术(SMILE)术后角膜光学质量的方法多基于单一的散射、衍射或像差因素,因此不能对角膜光学质量进行全面和客观评价,而调制传递函数(MTF)及斯特列尔比(SR)综合了上述多因素评价方法,是评估术后角膜光学质量方法学的研究方向. 目的 利用角膜MTF及SR客观分析SMILE术后术眼在明视和暗视环境下(分别为3 mm和6 mm瞳孔直径)角膜光学质量的变化.方法 采用系列病例观察研究方法和术眼手术前后自身对照研究设计,纳入2013年12月至2014年3月在天津市眼科医院接受SMILE的患者32例63眼,分别于术前、术后1周、1个月及3个月记录裸眼视力(UCVA)、最佳矫正视力(BCVA)和有效性指数(术后UCVA/术前BCVA);分别于上述时间点对术眼行电脑验光和综合验光仪验光,记录手术前后术眼屈光度变化;采用Sirius眼前节分析系统测定3 mm和6 mm瞳孔直径下不同空间频率(10、20、30、40、50和60 c/d)角膜前表面MTF和SR值,并测定术眼手术前后角膜前表面总高阶像差均方根值(RMS),以评估术眼SMILE手术前后角膜光学质量变化. 结果 术后1周、1个月、3个月UCVA(LogMAR)≥0.8者分别为59、62和63眼,分别占93.65％、98.41％和100％,术眼上述时间点有效性指数分别为1.104±0.128、1.126±0.145和1.158±0.208.术眼术后3个月等效球镜度和柱镜度均在正常范围.术眼术后各时间点3 mm瞳孔直径垂直及水平子午线各空间频率下MTF值较术前均明显增加,6 mm瞳孔直径下垂直子午线10、20、30和40 c/d空间频率MTF值较术前明显增加,差异均有统计学意义(均P＜0.05),而手术前后不同时间点6 mm瞳孔直径下水平子午线各空间频率MTF值总体比较差异均无统计学意义(均P＞0.05).术眼术后各时间点3 mm及6 mm瞳孔直径下的SR与术前相比呈上升趋势,差异均有统计学意义(均P＜0.05);且各时间点3 mm瞳孔直径下SR均大于相应的6 mm瞳孔直径下SR值,差异均有统计学意义(均P＜0.05).术眼手术前后不同时间点3 mm及6 mm瞳孔直径下角膜前表面RMS总体比较差异均无统计学意义(3 mm瞳孔直径:F=1.348,P=0.184;6 mm瞳孔直径:F=1.990,P=0.137). 结论 SMILE手术可有效改善近视及近视散光患者术后角膜光学成像质量,术眼术后明视环境下较暗视环境下角膜光学质量改善更为明显.     

近视患者优势眼与非优势眼的Kappa角、瞳孔大小及中心位置的动态变化

目的 探讨行飞秒激光制瓣准分子激光原位角膜磨镶术的近视患者优势眼与非优势眼的Kappa角、瞳孔大小及中心位置的动态变化.方法 选取2018年12月至2020年8月在延边大学附属医院眼科行飞秒激光制瓣准分子激光原位角膜磨镶术的近视患者117例(234眼)为研究对象.采用ALLEGRO Topolyzer角膜地形图仪(德国...     

Miotic effect of brimonidine tartrate 0.15% ophthalmic solution in normal eyes

PURPOSE: To evaluate the effect of brimonidine tartrate 0.15% ophthalmic solution (Alphagan P) on pupil diameter in eyes of healthy adults under different luminance conditions. SETTING: Center for Refractive Surgery, Ophthalmology Service, Department of Surgery, Walter Reed Army Medical Center, Washington, DC, USA. METHODS: Using a Colvard pupillometer, the pupil diameter was measured in 15 eyes of 15 healthy adults under 3 luminance conditions (scotopic, mesopic, photopic). The luminance of the room was measured using the Minolta LS-110 Luminance Meter. Pupil diameter was remeasured using the same technique 30 minutes, 4 hours, and 6 hours after administration of 1 drop of brimonidine tartrate 0.15% ophthalmic solution. RESULTS: Under scotopic conditions (luminance 0.0 candelas [cd]/m(2)), the pupil diameter decreased by 1.0 mm or more in 100%, 87%, and 60% of eyes at 30 minutes, 4 hours, and 6 hours, respectively (P<.005); under mesopic conditions (luminance 0.2 cd/m(2)), in 93%, 73%, and 40% of eyes, respectively (P<.005); and under photopic conditions (luminance 150.2 cd/m(2)), in 73%, 87%, and 67% of eyes, respectively (P<.005). CONCLUSIONS: Brimonidine tartrate 0.15% ophthalmic solution produced a significant miotic effect under all 3 luminance conditions. The reproducible miotic effect under scotopic and mesopic conditions may help postoperative refractive patients who report night-vision difficulties related to a large pupil.     

Comparison of different methods for pupillometry for mesopic and scotopic conditions

BACKGROUND: The aim of the study was to compare different methods for pupillometry, namely the Goldmann perimeter (gp), the Colvard pupillometer (cp) and the Procyon Video pupillometer (pvp). For the pvp three different illuminations were available: mesopic high, mesopic low, and scotopic. PATIENTS: The size of the pupil was measured in 100 eyes (50 healthy subjects) with the three different methods. We examined 29 females (58 %) and 21 males (42 %) with an average age of 25.16 years, ranging from 18 to 30 years. RESULTS: For the Goldmann perimeter, a mean pupil diameter of 4.39 mm +/- 0.62 mm was found under mesopic conditions (1.40 lux). For the Colvard pupillometer for scotopic conditions (0 lux), a mean pupil diameter of 6.80 mm +/- 0.81 mm was found. For pvp the pupil diameter ranged from 7.06 mm +/- 0.71 mm for scotopic (0.04 lux), over 6.24 mm +/- 0.80 mm for mesopic low (0.40 lux) to 4.65 mm +/- 0.73 mm for mesopic high conditions (4.00 lux). CONCLUSION: The comparison of the results showed a high correlation between the Goldmann perimeter and the Procyon Video Pupillometer for mesopic high with a minimum difference of 0.25 +/- 0.69 mm. By addition of 2.67 mm to the mesopic measurement of the Goldmann perimeter, the results for the Procyon Video pupillometer at the scotopic level, by addition of 2.4 mm the scotopic measurement of the Colvard pupillometer could be achieved.     

Changes in pupil size and centroid shift in eyes with uncomplicated in-the-bag IOL implantation

PURPOSE: To determine changes in entrance pupil size and pupil center shift under low mesopic and photopic conditions of illumination in eyes with in-the-bag intraocular lens (IOL) implantation. METHODS: Entrance pupil size and pupil center shift were measured under low mesopic (0.06 lux) and photopic (60 lux) conditions of illumination in 55 patients with unilateral pseudophakia (study group) and 55 age- and sex-matched patients with bilateral cataracts (control group) using the NIDEK OPD-Scan. Pseudophakic eyes had an uncomplicated intraoperative and postoperative course and best spectacle-corrected visual acuity of 20/20. Cataractous eyes had no additional ocular or systemic problems affecting the pupil. Both groups were analyzed with respect to pupil size and shift in both conditions of illumination. RESULTS: Mean patient age was 64.2 +/- 6.8 and 63.6 +/- 4.3 years in the study and control groups, respectively (P = .45). In the study group, differences in pupil size under low mesopic (5.12 +/- 1.02 and 5.13 +/- 0.96 mm for pseudophakic and phakic eyes, respectively) and photopic (3.44 +/- 0.39 and 3.45 +/- 0.39 mm for pseudophakic and phakic eyes, respectively) conditions of illumination were not statistically significant (P = 1.00 and P = .95 for pseudophakic and phakic eyes, respectively). Differences in pupil shift between pseudophakic (0.11 +/- 0.08 mm) and phakic (0.12 +/- 0.10 mm) eyes were not statistically significant (P = .83) in the study group. In the control group, differences in pupil size under low mesopic (P = .59) and photopic conditions of illumination (P = .60) in the right and left eyes as well as pupil shift (P = .71) were not statistically significant. CONCLUSIONS: Uncomplicated in-the-bag IOL implantation has no influence on pupil size and shift.     

Pupillodynamics and corneal spherical aberrations in a set of Indian cataract patients and its implications for aberrometric customisation of intraocular lenses

Purpose:Assessment of pupil diameter in various light conditions and the corresponding corneal spherical aberrations in a cohort of Indian eyes with bilateral senile cataracts and the possible use of this data in aberrometric customization of intraocular lenses (IOLs).Methods:In this prospective observational study done at a tertiary eye care centre in India, the selected patients were subjected to measurement of their pupil diameters in scotopic, mesopic, and photopic conditions as well as the corresponding corneal spherical aberrations, using the Sirius Topographer (Costruzione Strumenti Oftalmici, Florence, Italy). Shapiro–Wilk test, Independent t-test, ANOVA with Bonferroni correction on post-hoc testing were used for statistical analysis.Results:104 eyes of 52 patients were enrolled for the study. The mean age was 53 ± 11.88 years. The mean scotopic, mesopic, and photopic pupil sizes were 4.37 mm (4.11–4.63 mm), 3.92 mm (3.71 mm–4.15 mm), and 3.37 mm (3.18–3.67 mm), respectively. There was a statistically significant difference (P = <0.001) in the mean corneal spherical aberration measured at the 6 mm zone (0.23 ± 0.02 microns) and at the 4 mm zone (0.06 ± 0.01 microns).Conclusion:The mean corneal spherical aberration corresponding to the average mesopic pupil size of our patient population was substantially lower than that of the scotopic pupil size and also less than the amount corrected by most of the negative aspheric IOLs. This perhaps indicates the need for customising IOLs based on the spherical aberrations of cornea at the zone corresponding to the mesopic pupil diameter for optimal residual total postoperative spherical aberrations.     

Pupil center shift relative to the coaxially sighted corneal light reflex under natural and pharmacologically dilated conditions

PURPOSE: To evaluate the location and shift of the pupil center relative to the coaxially sighted corneal reflex on horizontal and vertical planes under natural and pharmacologically dilated conditions. METHODS: Ninety-four (64 myopic and 30 hyperopic) eyes of 47 patients underwent pupillometry with the NIDEK OPD-Scan under photopic and mesopic conditions before and after instillation of cyclopentolate 1%. Horizontal, vertical, and vectorial shift of the pupil center were calculated between each condition. RESULTS: The pupil center was located temporally to the coaxially sighted corneal reflex a mean distance of 0.336 +/- 0.181, 0.345 +/- 0.195, and 0.339 +/- 0.170 mm under photopic, mesopic, and pharmacologically dilated conditions, respectively. The pupil center shifted primarily inferotemporally (44%), followed by inferonasally (22%), superotemporally (19%), and superonasally (15%) from photopic to pharmacologic dilation. Mean magnitude of pupil shift was 0.084 +/- 0.069 mm (range: 0.010 to 0.385 mm) from mesopic to photopic, 0.149 +/- 0.080 mm (range: 0.013 to 0.384 mm) from photopic to pharmacologic dilation, and 0.102 +/- 0.104 mm (range: 0 to 0.530 mm) from mesopic to pharmacologic dilation. Mean distance between the pupil center and the coaxially sighted corneal reflex was greater in hyperopes than in myopes (P < .05), but no significant difference was observed in pupil center shifts between myopes and hyperopes under all three conditions (P > .05). CONCLUSIONS: The pupil center is located temporally and shifts in every direction, primarily inferotemporally, relative to the coaxially sighted corneal reflex with natural and pharmacologic dilation. The horizontal distance between the pupil center and the coaxially sighted corneal reflex was significantly higher in hyperopes than in myopes.     

Effect of brimonidine tartrate 0.2% ophthalmic solution on pupil size

PURPOSE: To evaluate the effect of brimonidine tartrate 0.2% ophthalmic solution on pupil size under scotopic and photopic luminance conditions in persons considering laser refractive surgery. SETTING: Ophthalmic Health Center, Tel Aviv, Israel. METHODS: The pupil size was measured in 36 eyes of 36 participants under scotopic and photopic conditions using the Colvard pupillometer (Oasis Medical) before and after brimonidine tartrate drops were administered. The pupil size was subsequently measured after 30 minutes and 4 and 6 hours. RESULTS: No difference was found in pupil size before brimonidine tartrate instillation in eyes with light or dark irides. Before instillation, the mean photopic pupil size was 4.81 mm +/- 0.54 (SD) (range 4.0 to 6.0 mm). At 30 minutes, all pupils became miotic, with a mean size of 3.77 +/- 0.51 mm (range 3.0 to 5.0 mm) (P<.0001). After 6 hours, 27.8% of the pupils had returned to their previous size. Before brimonidine tartrate administration, the mean scotopic pupil size was 6.22 +/- 0.73 mm (range 5.0 to 8.0 mm). There was significant miosis to 4.57 +/- 0.84 mm (range 3.0 to 6.5 mm) (P<.0001) that continued for at least 6 hours. The miotic effect of brimonidine tartrate was stronger in eyes with light irides. CONCLUSIONS: Brimonidine tartrate caused significant miosis, especially under scotopic conditions, most likely from its alpha-2 adrenergic effect. Under photopic luminance conditions, the miotic effect was pronounced.     

Measurement of the spatial shift of the pupil center

PURPOSE: To evaluate the effectiveness of the pupil center as an anatomic landmark for excimer laser treatments. SETTING: Sekal-Microchirurgia-Rovigo Centre, Rovigo, Italy. METHODS: Pupillometry with the Costruzione Strumenti Oftalmici S.R.L. (CSO) pupil-measuring module (incorporated in Eye Top videokeratoscope) was performed in 52 patients with a diagnosis of myopia and in 25 patients with a diagnosis of hyperopia. Measurements both in mesopic and photopic conditions consisted of pupil diameters, spatial shift of the pupil center, and the distance between the pupil center and keratoscopic axis. RESULTS: The mean pupil diameter in photopic conditions of illumination in myopic eyes was 3.52 mm +/- 0.56 (SD), while in mesopic conditions it was 5.37 +/- 0.78 mm; in hyperopic eyes the mean photopic pupil diameter was 3.01 +/- 0.46 mm, while the mean mesopic diameter was 5.12 +/- 0.48 mm. The mean spatial shift of the pupil center in myopic eyes was 0.086 mm (maximum 0.269 mm), while in the hyperopic eyes it was 0.095 mm (maximum 0.283 mm). The mean distance between the pupil center and keratoscopic axis in myopic eyes was 0.226 +/- 0.13 mm (maximum 0.75 mm), while in hyperopic eyes it was 0.45 +/- 0.19 mm (maximum 0.8 mm). CONCLUSIONS: The mean of the measured pupil sizes was greater in myopic eyes than in hyperopic eyes. The spatial shift of the pupil center, as the pupil dilates, was relatively small in all groups; therefore, the pupil center is a good anatomic landmark for both traditional refractive surgery and wavefront-guided treatments. The mean distance between the keratoscopic axis and pupil center was greater in the hyperopic group than in the myopic group. Therefore, centration of any laser treatment on the basis of the keratoscopic analysis should be done carefully, especially in hyperopic eyes and in cases in which the pupil center is meaningfully shifted from keratoscopic axis, even in photopic conditions of illumination.