The effect of pupil dilation on AL-Scan biometric parameters

The purpose of this study was to investigate the effects of pupil dilation on the parameters of the AL-Scan (Nidek Co., Ltd, Gamagori, Japan). We compared the measurements of axial length (AL), anterior chamber depth (ACD), central corneal keratometry reading, pupil diameter, and intraocular lens (IOL) power of 72 eyes of 72 healthy volunteers and patients scheduled for cataract surgery before and 45 min after instillation of cyclopentolate hydrochloride 1 % using the AL-Scan. Intraobserver repeatability was assessed by taking three consecutive recordings of ACD and AL. Only ACD readings were significantly different between predilation and postdilation (P < 0.001). The difference of the other measurements between two sessions was not statistically significant (P > 0.001). Only two cases in the study demonstrated changes in IOL power higher than 0.5 D. The intraobserver repeatability of both devices was good (CV values for ACD and AL were 0.16 and 0.20 %, respectively). Dilated pupil size did not affect the measurement of IOL power using the A-Scan optical biometer, but increase in ACD after dilation should be taken into account when performing refractive surgeries in which ACD is very important such as phakic anterior chamber IOL implantation.     

角膜白斑患者瞳孔再造术的疗效观察

探讨瞳孔再造术治疗角膜白斑的临床效果。方法17例（17只眼）角膜白斑患者行瞳孔再造术,患者角膜白斑直径为4-9 mm,视力均0．02以下,年龄30-78岁,机械性或化学性外伤致角膜白斑形成11例,角膜炎致角膜白斑形成6例。比较手术前后视力提高的程度,进行临床疗效观察。结果本研究结果中,术后视力0．5以上者3例（17．76％）,0．1-0．5者13例（76．47％）,0．01-0．1者1例（5．88％）。结论瞳孔再造术术后视力较术前明显提高。术后并发症少,手术方法简便,费用低,便于推广。     

散瞳对波前引导LASIK的影响

目的:探讨散瞳对波前引导的LASIK治疗近视的影响。方法:对216例(384眼)接受波前引导准分子激光原位角膜磨镶术(laser in situkeratomileusis,LASIK)的患者分两组,其中暗室条件下瞳孔直径<6.5mm行虹膜识别波前引导LASIK161例(291眼)为对照组;暗室条件下瞳孔直径≥6.5mm行无虹膜识别波前引导LASIK55例(93眼)为试验组,观察在暗室条件下对照组患者散瞳后瞳孔是否变形,暗室条件下试验组患者不散瞳,患者的瞳孔是否变形。对试验组瞳孔中心偏移者进行调整后再行手术,并与对照组比较。结果:两组瞳孔变形眼数比较(χ2=27.3814;P=0.000),有统计学意义。对无虹膜识别瞳孔中心有偏移的进行调整,两组比较(χ2=3.0944,P=0.0786;χ2=0.0017,P=0.9673;χ2=0.0706,P=0.7905),术后偏中心眼数、术后视力无统计学意义。结论:波前引导的LASIK在治疗近视时,散瞳易引起瞳孔变形和瞳孔中心偏移,有瞳孔中心偏移患者需进行调整,有益于提高视觉质量。     

散瞳前后瞳孔中心偏移对波前引导准分子激光原位角膜磨镶术手术的影响

目的探讨根据散瞳后的瞳孔中心调整切削区对波前引导的个体化准分子激光原位角膜磨镶术(LASIK)疗效的影响。方法瞳孔直径为6mm时高阶像差均方根(RMS)>035μm的近视患者32例(63只眼),随机分为A、B两组,接受Zyoptix个体化LASIK手术。A组以瞳孔中心为切削区中心,B组则根据测得散瞳后瞳孔中心的偏移量对切削区中心作相应调整。结果散瞳后瞳孔中心平均发生(0173±0114)mm的偏移,最大达051mm。术后3个月两组患者视力、屈光度数差异无统计学意义(P>005),波前像差检查显示手术前后彗差的差值分别为(0025±0137)和(0097±0118)μm(t=2131,P=0037),而球差差异无统计学意义(P>005)。B组彗差的矫正效果优于A组。结论散瞳后瞳孔中心普遍发生偏移,根据其偏移量在术中对切削区中心作相应调整可提高彗差的矫正效果。(中华眼科杂志,2005,412426)     

The pupil in stroke

Pupil sizes were assessed in 100 patients admitted to an intensive care stroke unit over a 1-year period to determine if differences existed and if anisocoria might help in diagnosis. From life-size photographs the pupil diameters were measured accurately, and clinical information compiled by the neurology staff was studied. Of the 19 patients with anisocoria 13 had a final diagnosis of stroke. This incidence of anisocoria, 16%, is similar to that in a normal population (20%). The side of the mydriasis was unrelated to the site of the lesions except when the stroke was due to a brainstem infarction; then ipsilateral Horner's syndrome occurred.     

Laser iris reconstruction in pupil deformities and dislocation in aphakia and pseudophakia

Up-to-date methods of laser iris reconstruction in pupil deformities and dislocation are presented (photomydriasis, corepraxia, synechiolysis).     

Effects of ultraviolet radiation and visible light on hamster pupil

Light does not cause a miotic response in mammals after a topical application of atropine. However, such common sense is based on the pupillary response to visible light. We found ultraviolet (UV) caused slight but evident miosis, even when the patient did not perceive visible light. In order to understand this mechanism further, we conducted in vitro experiments using hamsters. The in vitro hamster iris contracted even when the retina was withdrawn in an incubation solution. The contraction of the hamster pupil caused by visible light was inhibited by procaine, quinacrine, and by the withdrawal of divalent cations, but not by indomethacin, AA861, FPL55712 or autonomic blocking agents. UV-induced miosis was very delayed, continuing after cessation of UV stimuli. Nordihydroguaiaretic acid did not inhibit the miosis induced by UV and/or visible light. The UV-induced miosis was not significantly affected by allopurinol or verapamil, suggesting mechanisms other than neuronal mediation and oxidative stress. This study shows that the isolated hamster iris can react to UV and visible rays. UV-induced miosis is different from the miosis caused by light reflex. To our knowledge, UV-induced miosis has not yet been reported.     

Impact of iris pigment and pupil size in ultraviolet radiation cataract in rat

Purpose: To investigate the effect of iris pigment and pupil size in ultraviolet radiation (UVR)‐induced cataract. Methods: Brown‐Norway rats (pigmented) and Fischer‐344 rats (non‐pigmented) were unilaterally exposed in vivo to 5 kJ/m² UVR. Each strain was split into two groups, each receiving either mydriatic (tropicamide) or miotic (pilocarpine) eye‐drops. One week after exposure, the degree of ocular inflammation and damage in the anterior segment was determined. The lenses were extracted, photographed and the degree of forward light scattering (cataract) was quantified. Results: The cataract types differed between the two strains. All Fischer rats developed macroscopically identifiable UVR cataract while only 41% of Brown‐Norway rats did so. All groups except the miotic Brown‐Norway developed significant light scattering. The Fischer rats developed 3–4‐fold more lens light scattering than the Brown‐Norway rats. The miotic Fischer group exhibited significantly more light scattering than the mydriatic Fischer group. There was no significant difference in light scattering between the two Brown‐Norway groups. There was a correlation between ocular inflammation and degree of light scattering, with Brown‐Norway rats exhibiting less inflammation and lens light scattering. Conclusions: Pigmented rats develop less UVR cataract and less ocular inflammation than non‐pigmented rats. Pupil size plays a smaller role in UVR cataract development in pigmented rats than in non‐pigmented. The role of UVR‐induced ocular inflammation in cataract development is still ambiguous.     

激光虹膜切开与周边虹膜切除术治疗瞳孔闭锁继发青光眼的临床观察

目的 观察Nd:YAG激光虹膜切开术(LI)与虹膜周边切除术(PI)治疗瞳孔闭锁继发青光眼的临床疗效.方法 选取因葡萄膜炎引起瞳孔闭锁继发青光眼患者62例67只服,随机分为LI组和PI组.观察手术前后眼压、前房深度、炎症及虹膜切口通畅情况并进行统计学处理.平均随访时间(21.5±4.6)个月.结果 (1)LI组33只眼均能一次性击穿虹膜,前房深度由术前(0.67±0.31)mm加深为(2.58±0.26)mm,前后比较差异具有统计学意义.术后24h眼压南术前(28.22±7.12)mmHg降至(20.06±3.59)mmHg,前后比较差异具有统计学意义.术后26只眼(78.8%)发生激光孔闭合,未行再次激光治疗,22只眼行PI,4只眼行滤过手术.(2)PI组34只眼均形成通畅的周切口,术后结膜充血、前房炎症反应明显减轻.前房深度由术前(0.71±0.48)mm加深为(2.61±0.33)mm,前后比较差异具有统计学意义.眼压由术前(27.54±6.69)mmHg降至最未次随访(15.79±3.67)mmHg,前后比较差异具有非常统计学意义,手术成功率79.4%.结论 PI不仅能有效解除瞳孔闭锁、控制眼乐,而且有利于控制炎症、缩短疗程.     

The effect of pupil dilation on scanning laser polarimetry with variable corneal compensation.

BACKGROUND AND OBJECTIVE: The feasibility and reproducibility of scanning laser polarimetry performed through dilated pupils rather than through non-dilated pupils was tested. PATIENTS AND METHODS: One eye each of 36 subjects (12 normal, 12 suspected glaucoma, and 12 glaucoma) was scanned using a single GDx unit with variable corneal compensator (GDx-VCC; Laser Diagnostic Technologies, Inc., San Diego, CA). Two scans prior to and two scans after dilation were performed on each study eye, resetting the cornea compensation prior to each scan. The dilated eye was viewed off-center, such that the whitish focusing patch was projected on the 9-o'clock peripheral iris. After adequate anteroposterior focus, the pupil was centered and a scan was acquired. Each of 5 GDx parameters was evaluated comparing the pre-dilation and post-dilation scans. RESULTS: No statistically significant difference was found between pre-dilation and post-dilation measurements. There was a high pre-dilation to post-dilation correlation of 98%, 98%, 98%, 93%, and 95% for nerve fiber indicator, TSNIT average, TSNIT standard deviation, superior average, and inferior average, respectively. Less than 5% of the measurement variability was attributed to changes in pupil size (R2 ranging from 0.024 to 0.047). Stratifying the data by diagnostic groups yielded similar results. CONCLUSIONS: Pharmacologic mydriasis was not found to influence the retinal nerve fiber layer measurements acquired using the GDx-VCC. Results were comparable to scans achieved in the same eyes prior to dilation.     

Characterization of the pupil light reflex,electroretinogram and tonometric parameters in healthy rat eyes

PURPOSE: To characterize the pupil light reflex (PLR), electroretinographic (ERG) and tonometric parameters in healthy rat eyes. METHODS: Brown Norway rats were used for experiments. The PLR was evaluated with a computerized pupillometer (n = 27), ERGs were recorded simultaneously from both eyes (n = 27) and IOP was measured with a Tonopen (n = 15). RESULTS: The analysis of the PLR parameters confirmed that the consensual PLR had a significantly smaller amplitude (0.1-0.2 mm; p = 0.03) and an increased latency time (p = 0.001) compared to the direct PLR. Electroretinography revealed an a-wave amplitude of 207.2 +/- 13 microV with a latency of 25.6 +/- 0.7 ms, and a b-wave 554.3 +/- 24.5 microV with a latency of 21.4 + 1.8 ms. The flicker ERG recording revealed amplitudes of 40.6 +/- 2.4 microV. Tonometry measurements revealed that isoflurane, but not halothane, anesthesia suppressed the IOP (non-anesthetized: 25.3 +/- 1.0 mmHg; 1% halothane + 30% NO: 26.2 +/- 1.1 (p > 0.1); 1% isoflurane + 30% NO: 20.1 + 1.6 (p < 0.05)). CONCLUSIONS: Consensual PLR in rats has a relative deficit compared to the direct PLR. Isoflurane anesthesia has a suppressive effect on the IOP in healthy rat eyes.     

瞳孔成形联合虹膜夹型人工晶状体植入术临床观察

目的 观察瞳孔成形联合虹膜夹型人工晶状体植入术在外伤性白内障伴有虹膜损伤患眼中的疗效.方法 回顾性分析2010年5月至2011年8月在温州医学院附属眼视光医院眼外伤专科采用瞳孔成形联合虹膜夹型人工晶状体植入术治疗外伤性白内障伴有虹膜损伤患者,共8例8只眼.眼球钝挫伤3例,穿通伤5例,术前均确诊为外伤性白内障,其中3例伴有晶状体脱位.术后随访4～11个月,观察术后视力、角膜内皮细胞计数、瞳孔情况及人工晶状体位置、眼压等.结果 8例均成功修补损伤虹膜,顺利植入虹膜夹型人工晶状体.术后视力均达到或超过术前预测视力,术后矫正视力≥0.6共6只眼,占75％.瞳孔正常生理功能基本恢复,无明显畏光、眩光、复视等不适症状.虹膜夹型人工晶状体无明显偏位,无眼压升高、角膜内皮失代偿等情况.结论 瞳孔成形联合虹膜夹型人工晶状体植入术是治疗无囊膜支持的无晶状体眼合并虹膜损伤的相对安全、有效的方法之一.     

Characterization of the pupil light reflex,electroretinogram and tonometric parameters in healthy mouse eyes

PURPOSE: To characterize the pupil light reflex (PLR), electroretinographic (ERG) and tonometric parameters which might be of importance for the in vivo characterization of mouse models of chronic ocular hypertension. METHODS: C57/BL6 mice were used for experiments. The PLR was evaluated with a computerized pupillometer (n = 14), ERGs were recorded simultaneously from both eyes (n = 23) and IOP was measured with a modified Goldmann tonometer (n = 23). RESULTS: The analysis of the PLR parameters confirmed the consensual PLR did not have significantly different amplitude (p > 0.1) and latency time (p > 0.1) compared to the direct PLR. However, PLR velocity (p = 0.004) was significantly smaller in the consensual PLR. Electroretinography revealed a-wave amplitude of 168.3 +/- 9.6 microV with latency of 27.5 +/- 0.6 ms and b-wave 403 +/- 28.8 microV with latency of 22.7 +/- 0.6 ms. The flicker ERG recording revealed amplitudes of 20.6 +/- 2.4 microV. Tonometry experiments revealed that modified Goldmann tonometer measurements correlated well with invasive manometry (r(2) = 0.89). The mean IOP of the mouse was 15.3 +/- 0.6 mmHg. CONCLUSIONS: Consensual PLR in mice is relatively slower than the direct PLR, but retains the same degree of constriction comparing to the direct PLR. A modified Goldmann tonometer seems to be a reliable non-invasive tool for IOP measurements in mice.     

Comparison of the pupil card and pupillometer in measuring pupil size

PURPOSE: To determine the difference in pupil size measured with the Colvard pupillometer in mesopic and scotopic luminance and with the Rosenbaum pupil card in mesopic luminance between 2 examiners. SETTING: Michel Pop Clinics, Montreal, Quebec, Canada. METHODS: Two examiners used the Colvard pupillometer and the Rosenbaum card to measure pupil size in 58 eyes. The Colvard pupillometer was used in mesopic and scotopic light conditions. The Rosenbaum card was used in mesopic luminance only. Pupil size was evaluated with a 1.0 mm interval scale at the nearest half millimeter. RESULTS: For the 3 sets of data, the limits of agreement and coefficient of interrater repeatability were calculated and a 2 x 2 factorial analysis of variance was performed. Because of interexaminer bias, measurements done in mesopic luminance with the Rosenbaum card were not statistically different from those with the Colvard pupillometer in scotopic luminance, although interrater repeatability of the Colvard pupillometer (0.8 mm) was superior to that of the Rosenbaum card (1.3 mm). CONCLUSIONS: Examiner bias was the greatest statistical bias in all sets of measures. Surgeons may want to opt for a "safe" limit of pupil size (ie, 0.5 to 0.8 mm greater than the measured size) when calculating optical zones in refractive surgery. Future devices for pupil measurement should be based on automatic adjustment sizing.