Revisions to tolerances in cylinder axis and in progressive addition lens power in ANSI Z80.1-2005.

BACKGROUND: ANSI Z80.1 (American National Standards Institute) is a voluntary standard that provides tolerance guidelines for ophthalmic lens parameters. The recently approved ANSI Z80.1-2005 changes tolerances for cylinder axis for all ophthalmic lenses and for distance power for progressive addition lenses (PALs). METHODS: The ANSI Z80.1 committee analyzed the amount of unwanted residual cylinder created by rotating a cylinder axis away from its desired orientation for a range of cylinder powers. The limits of axis orientation error that keep the residual unwanted cylinder error within the tolerances for cylinder power were determined. For PALs, a tolerance for distance power error was sought that considers the currently followed standards for front surface power error and the tooling steps used for the rear surface. RESULTS: Tolerances for cylinder axis error were changed to +/-14 degrees for 0.25 diopter (D) cylinders and to +/-7 degrees for 0.50 D cylinders. Tolerance for error in back vertex power of PALs was changed to +/-0.16 D for both sphere and cylinder. CONCLUSION: Tolerances for cylinder axis for low cylinders have been made in ANSI Z80.1-2005 to be consistent with tolerances in cylinder power. Changes in tolerance for power errors in PALs have been made to recognize fabrication challenges.     

Comparison of Dioptron Nova refractive data with conventional refractive data

Refractive data obtained by means of the Dioptron Nova Diagnostic Eye Computer were compared to data obtained by conventional clinical refraction on a group of 236 clinic patients. Spherical equivalent power data were found to average -0.32 D more for Dioptron Nova data than for clinical data, whereas spherical power data averaged -0.25 D more for Dioptron Nova data than for clinical data, and cylinder power averaged -0.12 D more for Dioptron Nova data. Dioptron and clinical data were found to be within +/- 0.50 D of each other for 74% of eyes for spherical equivalent power, for 83% of eyes for spherical power, and for 91% of eyes for cylinder power. Cylinder axis data were found to be within +/- 10 degrees for the two methods for 78% of eyes.     

Binocular interactions in visual evoked cortical potentials with two light-emitting-diodes

Binocular interaction for a central field was studied with transient scalp visual evoked cortical potentials (VECPs) using two light-emitting-diodes. VECPs were obtained for binocular and monocular visions with dominant and non-dominant eyes, and arithmetical sums of monocular VECPs with dominant and non-dominant eyes were calculated. Amplitude and latency of remarkable initial three peaks were tested with the multivariate analysis of variance. Significant differences were noted among the four VECPs. Pairwise comparisons showed that (1) the amplitude of the first peak for the binocular VECPs was larger than that for the monocular VECPs but smaller than that for the sum-VECPs; the latency of the first peaks for the binocular VECPs were earlier than that for the monocular VECPs with the non-dominant eye; (2) the amplitude of the first negative peak for the sum-VECPs was larger than that for the binocular VECPs, and the peak latency for the sum-VECPs showed later than that for the binocular VECPs; (3) the amplitude of the second positive peak for the binocular VECPs and monocular VECPs with the dominant eye was larger than that with the non-dominant eye, but smaller for the binocular VECPS than that for the sum-VECPs; the latency for the binocular VECPs showed earlier than that for the monocular VECPs with the dominant eye and for the sum-VECPs. Binocular suppression was noted in amplitude for the three peaks and binocular facilitation was noted in latency for the latter two peaks. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic analysis of vergence measures in populations with varying incidences of strabismus.

Genetic parameters were contrasted for vergence amplitudes within three populations--esotropic, exotropic, and randomly selected populations-who differed in their incidence of subtypes of strabismus. In general, heritabilities for convergence exceeded those for divergence, and heritabilities for recovery points exceeded those for break points. Heritability estimates for diveregence amplitudes were significantly different for the random and esotropia populations, while convergence heritability estimates for these groups were similar. Thus, gene differences influencing divergence ability contributed to genetic variance for strabismus.     

三种不同固定液对豚鼠眼球的固定效果比较

目的：用过碘酸雪夫氏(Periodic Acid-Schiff, PAS)染色法比较4%多聚甲醛固定液、4%戊二醛固定液和Davidson 固定液固定豚鼠眼球的固定效果,筛选最佳眼球固定液和固定时间。

方法： 取正常豚鼠眼球分6组,每组5只,I组眼球放入4%多聚甲醛固定液固定24h、Ⅱ组眼球放入4%戊二醛固定液固定24h; Ⅲ～V组眼球放入Davidson 固定液分别固定3、6、24h; Ⅵ组眼球在Davidson 固定液中固定3h后转移到10%中性甲醛中再固定48h。常规制片、PAS染色、显微镜观察,比较不同固定方法对组织的固定效果。

结果：Davidson 固定液固定3h的固定效果最为理想,Davidson 固定液固定3h后转移到10%中性甲醛再固定48h的固定效果与Davidson 固定液固定3h的固定效果接近,这两组固定液固定的眼球切片均结构完整、层次清晰,视网膜各层细胞排列整齐。

结论： Davidson固定液对豚鼠眼球的固定效果明显优于其他两种固定液,豚鼠眼球用Davidson 固定液固定后,可将其转移到中性甲醛中长期保存,其固定效果不受影响。     

Corneal endothelial polymegathism induced by PMMA contact lens wear

Central corneal endothelial photographs were taken for 15 persons who had worn polymethylmethacrylate (PMMA) contact lenses for 7-15 yr and for a nonwearing control group matched for age and sex. An individual cell area analysis was made from the cell tracings. Significant endothelial polymegathism was noted for each member of the contact lens wearing group. PMMA wearers showed an average coefficient of variation of 0.445 for central corneal endothelial cell area compared to 0.245 for nonwearers (81.6% increase in polymegathism). The average maximum/minimum cell size ratio was 8.06 for the PMMA wearers vs 3.42 for the nonwearing control group. The frequency distributions for the cell areas reveal that the contact lens wearer develops cells that are much smaller and larger than normal.     

高度近视白内障手术治疗

目的探讨高度近视合并白内障超声乳化吸出联合人工晶状体植入手术的效果和并发症。方法回顾分析近4年在我院行超声乳化摘出联合人工晶状体植入的高度近视合并白内障256例（368眼）的治疗效果和并发症。结果术后1 d矫正视力〈0.1者6眼,占1.63%;0.1-0.3者49眼,占13.32%;0.3-0.5者184眼,占50.00%;0.5-0.6者87眼,占23.64%;0.6-0.8者28眼,占7.61%：0.8-1.0者11眼,占2.99%;≥1.0者3眼,占0.82%。术后3个月矫正视力〈0.1者5眼,占1.36%;0.1-0.3者38眼,占10.33%;0.3-0.5者157眼,占42.66%;0.5-0.6者112眼,占30.43%;0.6-0.8者36眼,占9.78%,0.8-1.0者15眼,占4.08%;≥1.0者5眼,占1.36%。并发症主要有：术中撕囊失败11眼（2.99%）,后囊破裂5眼（1.36%）,悬韧带断裂7眼（1.90%）,术后可逆性角膜水肿31眼（8.42%）,经治疗后1-2周消失;暂时性眼压升高11眼（2.99%）,继发性视网膜脱离2眼（0.54%）,经手术后恢复。结论高度近视合并白内障行超声乳化吸出联合人工晶状体植入既可治疗白内障,亦可矫正高度近视,术后视功能恢复较好。     

Efficiency of instillation methods for prostaglandin medications.

PURPOSE: The aim of this study was to determine the most efficient methods for instillation of prostaglandin analogs. METHODS: Drops were dispensed at room temperature from 2.5-mL bottles of bimatoprost, travoprost, and latanoprost. Two determinations of drop count were each made from bottles held vertically, at a 45-degree angle, and horizontally. The total volumes of medication dispensed from each bottle were measured. RESULTS: The mean number of drops dispensed was 111.0, 105.1, and 76.1 drops for bimatoprost bottles; 81.4, 101.1, and 85.3 drops for travoprost bottles; and 94.3, 88.4, and 67.1 drops for latanoprost bottles, held vertically, at 45 degrees, and horizontally, respectively. The mean volume of medication dispensed per 2.5-mL bottle was 3.17 mL for bimatoprost, 2.54 mL for travoprost, and 3.02 mL for latanoprost. The most efficient instillation methods provided 56 days of bilateral therapy per 2.5-mL bottle for bimatoprost, 51 days for travoprost, and 47 days for latanoprost, with corresponding yearly medication costs of $408 for bimatoprost, $449 for travoprost, and $475 for latanoprost. Yearly savings of $109 to $192 could be achieved by using the most efficient instillation methods, representing 5.6 months of medication saved for patients using bimatoprost, 3.0 months for patients using travoprost, and 4.9 months for patients using latanoprost. CONCLUSIONS: Health care providers are urged to instruct glaucoma patients in the most efficient method of instillation. For bimatoprost and latanoprost, vertical instillation is recommended, with 45 degrees nearly as efficient, and for travoprost, instillation at 45 degrees is recommended.     

Telemedical evaluation of ocular adnexa and anterior segment

PURPOSE: To report the accuracy of telemedical slit-lamp evaluation in examination of ocular adnexa and anterior segment. METHODS: By means of contingency tables, slit-lamp findings by live examination and by real-time telemedicine were compared in 50 eyes of 25 patients. RESULTS: Sensitivity percentages (proportion with findings correctly identified by telemedicine)/specificity percentages (proportion without the finding that was correctly identified by telemedicine) were 100/64 for eyelid mass, 100/85 for conjunctival pigment, 100/100 for posterior synechiae, 80/0 for blepharitis, 83/93 for iridotomy, 70/93 for pinguecula, 75/93 for iris lesions, 56/98 for corneal scar, 0/100 for chamber inflammation, 57/93 for nuclear cataract, and 37/100 for intraocular lens presence. CONCLUSIONS: By means of monocular slit-lamp telemedical evaluation, clinical findings with high contrast cues for color and depth have the highest sensitivity and specificity.     

Vision out of the corner of the eye

The margin of the temporal visual field lies more than 90° from the line of sight and is critical for detecting incoming threats and for balance and locomotive control. We show (i) contrast sensitivity beyond 70° is higher for moving stimuli than for stationary, and in the outermost region, only moving stimuli are visible; (ii) sensitivity is highest for motion in directions near the vertical and horizontal axes and is higher for forward than for backward directions; (iii) the former anisotropy arises early in the visual pathway; (iv) thresholds for discriminating direction are lowest for upward and downward motion.     

Secondary intraocular lens implantation: methods and complications

PURPOSE: We report a review of the literature on complications of secondary lens implantation without capsular support. METHODS: We assessed results and complications after trans-sulcus sclera l fixation (SSIOL), open-loop anterior chamber intraocular lens (ACIOL) and iris-claw lens (ICIOL). RESULTS: Series published in the literature showed variable results. The rate of increased visual acuity ranged from 71% to 92% for SSIOL, 77% to 92% for ACIOL, 83% to 100% for ICIOL. Complications included: decentration and tilt of th IOL in 0-15.3% for SSIOL, 0-8.6% for ACIOL, 1.8-4.8 % for ICIOL; retinal detachment in 1.1-6% for SSIOL, 0-3.3% for ACIOL; cystoid macular edema in 5.8-23% for ACIOL, 4.8%-5.2% for ICIOL; bullous keratopathy in 0-26.3% for SSIOL, 0-14.2% for ACIOL, 4.8% for ICIOL. Vitreous hemorrhage and suture erosion were specific complications report ed for SSIOL in 1.1-25% and 15-20% of cases respectively. CONCLUSION: Secondary IOL implication is a good alternative for correction of aphakia eyes without a posterior capsule. This analysis shows no one procedures offers more safety than the others. The decisive facto r for choosing among the different types of IOL appears to be surgical experience.     

Towards Improved Standards for Automotive Eye Protection

The requirements are considered for a reassessment of the Australian Standards relating to eye protection for vehicle users, particularly for motorcycle users. The interlocking requirements of the Australian Standards for vehicle users' helmets and for automotive eye protection are illustrated. Light transmittance requirements for windscreen, visors, and goggles are reviewed and the case for tinted eye protection for daytime use considered. The contribution of surface scratching to glare is assessed. Impact test procedures for a series of related Standards are reviewed. The possible contribution of eye protection to crash injur) is considered. and some of the available data sources from in-depth accident studies are summarised.     

选择及放弃激光角膜屈光手术近视患者3000例原因调查

目的：调查近视患者要求激光角膜屈光手术的原因和术前检查后放弃手术的原因。方法：对3000例准备行激光角膜屈光手术的近视患者进行关于要求手术原因的问卷调查,并对所有患者例行术前检查,分析患者要求手术的原因和其中349例检查后放弃手术的原因。结果：患者要求手术的原因依次为：为了顺利通过升学、择业或入伍等体检（47.60%）;为运动、美观、舒适性等考虑而自身不愿戴镜,占46.80%;由于近视度数过大或严重屈光参差而不便戴镜（4.40%）。3000例患者中未能最终行手术者349例,占11.63%,因心理因素及社会因素放弃者116例（33.24%）;各类手术禁忌证233例（66.76%）。结论：激光角膜屈光手术术前可根据患者手术原因更有针对性地加强医患沟通;术前检查应详细认真,严格掌握手术的适应证及禁忌证,确保手术安全;医务工作者有责任对广大近视患者普及近视预防、治疗的相关知识,使患者能正确选择治疗方法。     

Analysis of errors in letter acuity measurements

This study examined the possibility of increasing the precision of letter visual acuity measurements by investigating the basis for two methods of fractional grading of responses. The first method concerns the varying legibility/readability of letters and the second is concerned with the recognition of two classes of errors, those that are completely wrong (for example, O for H) and those that are partially wrong, because they are reasonable substitutes for the correct letter when the incorrect response has significant shape features in common with the correct letter (for example, N for H). Errors made when visual acuity is measured were analysed for two samples of 200 subjects, each group viewing a different version of the Bailey-Lovie letter chart. Varying legibility and readability for the 10 letters used to construct these charts have been demonstrated, the most common errors occurring for F, H, and V, and the least common errors occurring for U and Z. Chi-square tests indicated that incorrect letter responses are not randomly distributed (p < 0.001) for all chart letters. The most common reasonable substitutes found were P for F, Yfor V, F for P, H for N, N for H, O for D, B and R for E and P for R. The conclusion is drawn that the potential for finer scaling of letter acuity measurements that accounts for varying legibility and readability of letters and discriminates between completely wrong responses and partially correct responses (reasonable substitutions) has been demonstrated. We propose that the weighting of responses according to these mechanisms for finer scaling may increase the precision of letter chart measurement of visual acuity as an aid to scientific investigation as well as to the monitoring of visual function in clinical practice. The use of a detailed weighting system would be facilitated by computer assisted calculations and will be the subject of a future report.     

Some dynamic features of depth perception

Disparity cues affect a subject's ability to detect movement only when stimulus oscillation frquency is less than 1 Hz. Disparity cues then increase sensitivity for targets close to the fixation plane (within 7.5′), but decrease sensitivity for targets whose disparities are greater. Binocular sensitivity to sideways movement is higher for targets in the fixation plane than for targets with finite disparities. The effect of frequency upon depth sensitivity is different for crossed, uncrossed and zero disparities. Suprathreshold depth sensitivity has a steeper high-frequency attenuation for uncrossed than for crossed disparities. One “stereoanomalous” subject could see depth for crossed disparities but gave no depth responses at all for uncrossed disparities.     

Visual acuity for optotypes made visible by relative motion

There are several visual mechanisms for analyzing spatial information additional to the much researched mechanism sensitive to luminance contrast. We describe a Snellen-type acuity test for motion-defined (MD) letters. Acuity for these MD letters collapsed at dot speeds slower than 0.05 deg/s, but acuity for contrast-defined (CD) letters was unaffected by speed over the entire 0 to 0.3 deg/s range used. Acuity was a power function of presentation duration for both kinds of letter, but the exponent was higher for MD than for CD letters. Acuity for MD letters was comparatively unaffected by dot density from 50 to 0.05%, below which it suddenly collapsed to zero. On the other hand, acuity for CD letters progressively fell as dot density was reduced from 50%, and below about 0.5% approximated acuity for MD letters.     

The development of measurement tools for prosthetic eye research

Background: The aim was to develop tools to measure the condition of ocular prostheses and the socket's response to prosthetic eyewear. Methods: A novel staining technique for displaying deposits on prosthetic eyes was developed. Equal interval perceptual grading scales for measuring inferior palpebral conjunctival inflammation, and anterior and posterior stained surface deposits on prosthetic eyes were developed from 800 photographs of 43 volunteers. The photographs for each scale were chosen by the authors. A group of four ophthalmologists, three optometrists and three senior students was consulted about selection criteria and asked to position the photographs along a 1.5 m rule to determine equal intervals. Photographs judged not to represent exactly equal perceptual intervals were exchanged with others from the original pool. The final scales (a five‐photograph scale for inflammation and two 11 photograph scales for deposits) were assessed for inter‐rater reliability and test‐retest reliability by groups of senior optometry students. Results: Standard deviations for inter‐rater reliability tests were 0.52 scale units for the inflammation scale, 0.99 for the anterior surface deposits scale and 1.03 for the posterior surface deposits scale. The standard deviation of the test‐retest differences for inflammation was 0.6 scale units and for both anterior and posterior surface deposits it was 0.71. Conclusions: A novel technique for displaying and measuring the intensity and extent of deposit formation on prosthetic eye surfaces has been described. The two equal interval perceptual grading scales that have been developed to quantify the extent of deposit formation together with the equal interval perceptual scale for grading severity of palpebral conjunctival inflammation will for the first time allow the effects of prosthetic eye wear to be evaluated. Further research to validate the scale for palpebral conjunctival inflammation in a clinical setting is recommended. The technique for staining deposits on prosthetic eyes is recommended for clinical practice.     

The Difference in Saccadic Parameters among Several Visually Guided Tasks-Saccadic Reaction Time

Purpose: The saccadic reaction time (SRT) was measured as a saccadic movement parameter using visually guided tasks.Subjects and Method: The SRT was measured for nine healthy adult subjects aged from 28 to 49 years. The visually guided tasks for saccadic movement induction were simultaneous, gap, overlap, delayed-memory, and anti-SM tasks.Results: The median of the SRT (msec) for each task in the actual measurements was as follows: 216 for the simultaneous task, 180 for the gap task, 240 for the overlap task, 234 for the delayed-memory task, and 292 for the anti-SM task. The SRT distribution of each subject exhibited two peaks for the gap task but mostly one peak for each of the other tasks. The first peak, observed in the SRT distribution for the gap task was an eysress saccade.Conclusion: The SRT for the gap task was the shortest and the SRT got longer in the order of the simultaneous task, and the overlap task, and the anti-SM task. Some subjects easily showed an express saccade in the gap task, but others did not.     

Ciprofloxacin and levofloxacin resistance among methicillin-sensitive Staphylococcus aureus isolates from keratitis and conjunctivitis

PURPOSE: The majority of Staphylococcus aureus isolated from ocular infections are methicillin sensitive (MSSA). Fluoroquinolone resistance among methicillin- resistant Staphylococcus aureus is well known but not among MSSA. In this study we investigate the emergence of fluoroquinolone (ciprofloxacin, levofloxacin) resistance among methicillin-sensitive Staphylococcus aureus isolates from keratitis and conjunctivitis. DESIGN: Cross-sectional study. METHODS: Minimal inhibitory concentration susceptibility profiles for 1230 S. aureus isolates from keratitis and conjunctivitis were analyzed. Historical and current rates of emerging fluoroquinolone resistance for methicillin-resistant (MRSA) and methicillin-sensitive isolates (MSSA) were evaluated. Sensitivity patterns for vancomycin and gentamicin were also documented. RESULTS: Ciprofloxacin resistance among corneal and conjunctival S. aureus isolates during the first 6 years after its introduction (baseline) (1990-1995) was 8% and ranged from 3% to 11%. The rate for the most recent 6 years (current) (1996-2001) was 20.7%. Baseline ciprofloxacin resistance for MSSA isolates was 2% vs 55.8% for MRSA. The current resistance rate for MSSA is 5% vs 83.7% for MRSA. The general resistance rate from January 2000 to December 2001 for levofloxacin was 25.5% vs 33.2% for ciprofloxacin (P =.13). The levofloxacin-resistance rate for MSSA was 4.7% vs 11.9% for ciprofloxacin (P =.05). In MRSA isolates, a higher resistance rate was found for ciprofloxacin (95.7%) vs levofloxacin (82.1%) (P =.04). No resistance for vancomycin was documented for any of the S. aureus isolates. Gentamicin susceptibility for MSSA was 99% and MRSA was 86%. CONCLUSIONS: Ciprofloxacin and levofloxacin resistance among methicillin-sensitive S. aureus corneal and conjunctival isolates is increasing. This is of concern because it narrows treatment choices for the management of these common ocular infections.     

不同临床经验医师应用LOCSⅢ对晶状体混浊程度评分的一致性研究

目的　评价不同临床经验医师应用晶状体混浊分级系统（Lens Opacity Classification SystemⅢ,LOCSⅢ）,基于裂隙灯及数码照片进行晶状体混浊程度评分的一致性。方法　从邯郸眼病研究5 a随访项目中,随机选取2012年11月至2012年12月现场调查受试者51人（102眼）。首先由受过LOCSⅢ评分培训的高年资眼科副主任医师（评分员A）于现场参照LOCSⅢ标准图片,在裂隙灯下对晶状体核混浊程度（nuclear opacity,NO）、核颜色（nuclear color,NC）、皮质性白内障（cortical cataract,C）、后囊膜下白内障（posterior subcapsular cataract,PSC）进行评分,随后采集晶状体数码照片。评分员A和1名眼科住院医师（评分员B）根据晶状体数码照片独立进行NO、NC、C、PSC评分。然后一位经过LOCSⅢ晶状体评分培训的白内障专业副主任医生对评分员B进行培训,同时与评分员A进行讨论并统一对LOCSⅢ标准评分方法的理解后,评分员B进行第2次评分。均采用组内相关系数（intraclass correlation coefficient,ICC）分别检验评分员A基于裂隙灯及数码照片的LOCSⅢ晶状体评分的一致性,评分员B培训前、后的LOCSⅢ晶状体评分的一致性,以及评分员B培训前、后的LOCSⅢ晶状体评分与评分员A基于裂隙灯及数码照片的LOCSⅢ晶状体评分进行一致性检验。结果　评分员A基于现场裂隙灯和晶状体数码照片的LOCSⅢ晶状体评分的ICC分别为:NO 0.89、NC 0.89、C 0.90、PSC 0.65;评分员B培训前、后LOCSⅢ晶状体评分ICC分别为:NO 0.90、NC 0.90、C 0.89、PSC 0.12;评分员B培训前、后基于数码照片与评分员A基于裂隙灯的LOCSⅢ晶状体评分ICC分别为NO 0.77、0.82,NC 0.79、0.85,C 0.77 、0.89,PSC 0.05、0.46;评分员B培训前、后与评分员A基于数码照片的LOCSⅢ晶状体评分比较ICC分别为:NO 0.83、0.81,NC 0.80、0.84,C 0.76 、0.88,PSC 0.26、0.85。结论　眼科临床经验对临床医师采用LOCSⅢ进行NO、NC、C评分影响不大,对PSC评分影响较大,而LOCSⅢ标准评分方法培训可以弥补眼科医师临床经验的不足,但不能提高基于裂隙灯和数码照片的LOCSⅢ对PSC评分的一致性。