Comparison of visual performance between peripheral gradient high-addition multifocal soft contact lenses and orthokeratology

Purpose

The aim of this study was to evaluate the short-term effects of peripheral gradient high-addition multifocal soft contact lenses (MFSCLs) and orthokeratology (Ortho-K lenses) on visual performance in myopic children.

Methods

Thirty myopic children participated in this prospective study. Each participant wore different sets of lenses in the following sequence: single-vision spectacles (SVSPs) as a control, MFSCLs and Ortho-K lenses. Ocular aberrations, topography, high-contrast visual acuity (HCVA), low-contrast visual acuity (LCVA) and accommodation of the right eye were measured with each type of correction on a different day.

Results

Compared with SVSPs, high-addition MFSCLs and Ortho-K lenses significantly increased all items of aberrations (all p < 0.05) except trefoil (p = 0.17). MFSCLs induced less coma, root mean square of the third-order aberration (RMS3) and higher order aberrations than Ortho-K lenses (all p < 0.05). No significant difference in HCVA was found across the three correction types (F = 1.19, p = 0.39). In terms of LCVA, MFSCLs performed significantly poorer than SVSPs (difference, 0.16 logMAR; p = 0.001) and slightly worse than Ortho-K lenses (difference, 0.08 logMAR; p = 0.35). No significant difference in decentration was found between the two types of contact lenses, and no associations were observed between decentration and visual acuity at both high- and low-contrast levels (all p > 0.05). For MFSCLs, decentration was positively related to coma (r = 0.43, p = 0.02) and RMS3 (r = 0.44, p = 0.02), which was not the case for Ortho-K lenses. Accommodative facility was worse with MFSCLs than Ortho-K lenses (p = 0.001).

Conclusion

Multifocal soft contact lenses differed from Ortho-K lenses in aberration profile and LCVA, although decentration was similar. Decentration <1 mm had minimal influence on both HCVA and LCVA for either type of correction, but significantly increased third-order aberrations for MFSCLs, but not Ortho-K lenses.     

Inefficacy of aspheric soft contact lenses for the correction of low levels of astigmatism.

PURPOSE: The purpose of this article is to compare the visual performance of a toric soft (TS) contact lens (SofLens 66 Toric; Bausch & Lomb, Rochester, NY), an aspheric soft (AS) contact lens (Frequency Aspheric; CooperVision, Fairport, NY) and a spectacle correction (SC) in subjects with low levels of astigmatism. METHODS: One eye of 30 subjects with refractive astigmatism of -0.75 DC or -1.00 DC was tested. After pupil dilation, each subject was fitted with all three forms of correction in random order. Subjects were masked from the contact lens type. High-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA) were recorded for each correction using 2-mm, 4-mm, and 6-mm artificial pupils. RESULTS: With a 2-mm pupil, HCVA was similar for the TS lens and the SC (p = 0.13); better HCVA was demonstrated with the TS lens than with the AS lens (p = 0.001). With 4-mm and 6-mm pupils, HCVA was poorer with the AS lens than with the SC (p < 0.002) and TS lenses (p < 0.0001). The difference in HCVA between the TS and AS lenses was two letters, three letters, and one line with pupil sizes of 2 mm, 4 mm, and 6 mm, respectively. LCVA was similar for the three refractive conditions with the 2-mm pupil size. With 4-mm and 6-mm pupils, LCVA was similar for the TS lens and SC, but better than the AS lens by approximately one line in each case (all p < 0.0001). CONCLUSIONS: For small pupil sizes, there is little difference in HCVA and LCVA between various refractive corrections. However, for larger pupils, HCVA and LCVA are superior with TS contact lenses and SC versus AS contact lenses by approximately a half-line or more, which is considered to be clinically significant. Superior vision can be achieved for low astigmatic contact lens wearers using TS rather than AS contact lenses.     

Is the high contrast visual acuity chart a good predictor of improvement in visual acuity with low vision aids?

Purpose:To assess whether the objective improvement seen with HCVA chart using LVAs correlates with subjective improvement in the quality of life as measured on low vision quality of life (LVQOL) questionnaire of such patients.Methods:This was a prospective, consecutive, observational study. Objective improvement in visual function was assessed using LVAs with high contrast LogMAR visual acuity chart for near and distance. Subjective improvement for distance was assessed using LVQOL score for “distance mobility and lighting”, whereas for near it was assessed using the LVQOL score for “near and fine work”. A total of 46 patients completed one follow-up after low vision trial and were included in the study.Results:Improvement in objective visual acuity was highly significant for both near and distance (P < 0.001) with LVAs. LVQOL score improved from 65.85 to 76.83 after one of using low vision aids (P < 0.001). The improvement in LVQOL score for distance and mobility was also highly significant (2.55; P < 0.001); and so was for near and fine work (5.89; P < 0.001). However, Spearman rank correlation coefficient showed no correlation between improvement in visual acuity for distance and LVQOL score improvement for distance (r_s = –.086; P = 0.57). For near also, improvement in acuity did not correlate with the LVQOL score improvement for near and fine work (r_s = 0.036; P = 0.81).Conclusion:No statistical correlation was observed between the improvements measured by objective HCVA charts and subjective improved as perceived by the patient after use of low vision devices.     

Visual performance of aspherical and spherical intraocular lenses: intraindividual comparison of visual acuity, contrast sensitivity, and higher-order aberrations

PURPOSE: To intraindividually compare visual performance in terms of photopic high-contrast visual acuity (HCVA), mesopic HCVA, mesopic low-contrast visual acuity (LCVA), and contrast sensitivity (CS) in patients after implantation of either an aspherical or a spherical intraocular lens (IOL). SETTING: Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany. METHODS: Forty eyes of 20 patients were randomized to implantation of an aspherical IOL (Tecnis Z9000, AMO) in 1 eye and a spherical IOL (Sensar AR40e, AMO) in the other eye. Three to 4 months postoperatively, photopic HCVA (270 cd/m(2)) was measured with the observer-independent Frankfurt-Freiburg Contrast and Acuity Test System (FF-CATS) and high-mesopic HCVA and LCVA (8 cd/m(2)) were measured with Early Treatment Diabetic Retinopathy Study charts. CS was assessed with the FF-CATS under photopic (167 cd/m(2)), high-mesopic (1.67 cd/m(2)), and low-mesopic (0.167 cd/m(2)) luminance conditions with and without glare. For each individual eye, higher-order wavefront aberrations were reconstructed for a physiological mesopic pupil diameter. Intraindividual differences (Delta(i)) in visual acuity, contrast sensitivity, and higher-order aberrations (HOAs) were calculated, and the influence of age and Delta(i) HOA on Delta(i) contrast sensitivity (logCS) under high-mesopic conditions was investigated using multiple regression analysis. RESULTS: There were no statistically significant differences between the Tecnis IOL and the Sensar IOL in visual acuity measurements or contrast sensitivity measurements. For physiological mesopic pupil diameter, primary spherical aberration (Z(4)(0)) was significantly lower in the Tecnis group (P<.001). For all parameters studied except Z(4)(0), the Delta(i) values were distributed around zero. Multiple regression analysis showed only a partial influence of Delta(i) Z(4)(0) on Delta(i) logCS (adjusted R(2) = 0.49) but did not show any influence of age, coma-like aberration, or residual HOA. CONCLUSIONS: Although Z(4)(0) was significantly lower in the eyes with the aspherical IOL, no statistically significant differences were found between aspherical and spherical IOLs in LCVA, HCVA, and contrast sensitivity. Statistical analysis of intraindividual contrast sensitivity differences showed that in most patients, this Z(4)(0) difference was too low to have an effect on contrast sensitivity.     

Impact on visual function from light scattering and glistenings in intraocular lenses,a long‐term study

Purpose: To investigate the impact on visual function from light scattering and glistenings in intraocular lenses (IOLs) in patients who had cataract surgery 10 years previously. Setting: Eye clinic, Norrlands university hospital, Umeå, Sweden. Methods: One hundred and three patients, who had phacoemulsification with implantation of Acrysof^® MA60BM IOLs 10 years previously, were evaluated with best corrected visual acuity (VA), and low contrast visual acuity (LCVA) 10% and 2.5%. The light scattering from the IOLs was measured by Scheimpflug photography. The degree of glistenings was also quantified at the slit‐lamp. Eyes with coexisting pathology that could affect VA and LCVA were excluded. Results: The patients were divided into various groups according to the degree of light scattering and grade of glistenings. In two subsets of patients, paired data from the patients’ eyes were analysed. It was not possible to detect any significant impact on visual function, best corrected visual acuity (BCVA) and LCVA 10% and 2.5% in eyes with a more pronounced light scattering or a higher grade of glistenings seen at the slit‐lamp. The correlation between IOL dioptric power and both the total light scattering of the IOL, and the subjective grading of the intensity of the glistenings at the slit‐lamp was statistically significant (r_P = 0.25; p = 0.012; r_S = 0.23; p = 0.019, respectively). Conclusion: Most patients in this case series operated 10 years previously had severe glistenings and a high level of light scattering from their intraocular lenses. No detectable impact on BCVA, LCVA 10% and 2.5% was found.     

灯箱视力表与Freiburg电子视力表应用对比研究

目的 比较灯箱视力表与Freiburg电子视力表结果的一致性与可重复性,评价Freiburg电子视力表的临床应用价值。设计 诊断性技术评价。研究对象 空军杭州航空医学鉴定训练中心的工作人员86例,平均年龄（26.3±2.1）岁。方法 所有入选者均随机由2位固定检查者分别使用灯箱视力表和Freiburg电子视力表进行检查,两种视力表检查的顺序随机决定。所有检查均在同一房间内完成,房间内亮度小于3 lux。检查距离均为3 m。对不同视力表间与检查者间测量重复性采用配对t检验比较结果的差别并计算相关系数r值。主要指标 使用两种视力表获得的logMAR视力。结果 在检查者一,用灯箱视力表查,被检者logMAR视力为0.19±0.23,Freiburg电子视力表0.20±0.15,两者差值为-0.011±0.141,差异无统计学意义（t=-0.741, P=0.461）,但有显著相关性（r=0.808,P=0.000）。在检查者二,用灯箱视力表查,被检者logMAR视力为0.32±0.25,Freiburg电子视力表为0.20±0.15,两者差值为-0.118±0.151,差异有统计学意义（t=7.191, P=0.000）及显著相关性（r=0.810,P=0.000）。均用灯箱视力表,检查者一、二的差异有统计学意义（F=11.872,P=0.001）,两者显著相关（r=0.938,P=0.000）。而均用Freiburg电子视力表,检查者一、二的差异无统计学意义（F=0.019,P=0.890）,两者显著相关（r=0.986,P=0.000）。结论 Freiburg电子视力表受检查者因素的影响小于灯箱视力表,其在不同测量者间的可重复性优于灯箱视力表。（眼科, 2013, 22: 117-120）     

Novel Foveal Features Associated With Vision Impairment in Multiple Sclerosis

PurposeTo characterize scattering and hyperreflective features in the foveal avascular zone of people with multiple sclerosis (MS) using adaptive optics scanning laser ophthalmoscopy (AOSLO) and to evaluate their relationship with visual function and MS disease characteristics.MethodsTwenty subjects with MS underwent confocal reflectance and non-confocal split-detection AOSLO foveal imaging. Peripapillary retinal nerve fiber layer thickness was measured using optic nerve optical coherence tomography. Blood pressure, intraocular pressure (IOP), and best-corrected high-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA) were measured. AOSLO images were graded to determine the presence and characteristics of distinct structures.ResultsTwo distinct structures were seen in the avascular zone of the foveal pit. Hyperreflective puncta, present in 74% of eyes, were associated with IOP and blood pressure. Scattering features, observed in 58% of eyes, were associated with decreased HCVA and LCVA, as well as increased MS duration and disability, but were not associated with retinal nerve fiber layer thickness. Hyperreflective puncta and scattering features were simultaneously present in 53% of eyes.ConclusionsHyperreflective puncta were associated with parameters affecting ophthalmic perfusion, but they were not associated with MS disease parameters. Scattering features were associated with parameters corresponding to advanced MS, suggesting that they may be related to disease progression. Scattering features were also correlated with reduced visual function independent from ganglion cell injury, suggesting the possibility of a novel ganglion cell–independent mechanism of impaired vision in people with MS.     

Prevalence of Visual Impairment and Uncorrected Refractive Error – Report from a Canadian Urban Population-based Study

Abstract

Purpose: The prevalence of visual impairment due to uncorrected refractive error has not been previously studied in Canada. A population-based study was conducted in Brantford, Ontario.

Methods: The target population included all people 40 years of age and older. Study participants were selected using a randomized sampling strategy based on postal codes. Presenting distance and near visual acuities were measured with habitual spectacle correction, if any, in place. Best corrected visual acuities were determined for all participants who had a presenting distance visual acuity of less than 20/25.

Results: Population weighted prevalence of distance visual impairment (visual acuity <20/40 in the better eye) was 2.7% (n?=?768, 95% confidence interval (CI) 1.8–4.0%) with 71.8% correctable by refraction. Population weighted prevalence of near visual impairment (visual acuity <20/40 with both eyes) was 2.2% (95% CI 1.4–3.6) with 69.1% correctable by refraction. Multivariable adjusted analysis showed that the odds of having distance visual impairment was independently associated with increased age (odds ratio, OR, 3.56, 95% CI 1.22–10.35; ≥65 years compared to those 39–64 years), and time since last eye examination (OR 4.93, 95% CI 1.19–20.32; ≥5 years compared to ≤2 years). The same factors appear to be associated with increased prevalence of near visual impairment but were not statistically significant.

Conclusions: The majority of visual impairment found in Brantford was due to uncorrected refractive error. Factors that increased the prevalence of visual impairment were the same for distance and near visual acuity measurements.     

智能视力表投影仪的可重复性及其与传统视力表的比较

目的：分析智能视力表投影仪在视力检查中的可重复性及其与传统视力表测量结果的比较。方法：系列病例研究。收集2022年1月4—22日在首都医科大学附属北京同仁医院就诊的眼部不适患者60例（120眼）。先通过智能视力表投影仪（LSJ-IVAC-6000A）对患者进行3次视力检测,并采用组内相关系数（ICC）评价3次测量结果之间的可重复性;再用传统灯箱的国家标准视力表测量1次,并分别采用ICC和Bland-Altman图表法分析智能视力表投影仪与传统视力表检测结果的一致性。结果：同一受检者右眼、左眼使用智能视力表投影仪测量3次的ICC值分别为0.830和0.868,双眼的ICC值均>0.8（P<0.001）;同一受检者右眼、左眼使用智能视力表投影仪和传统灯箱的国家标准视力表测量的ICC值分别为0.846和0.873,双眼的ICC值均>0.8（P<0.001）。右眼、左眼使用智能视力表投影仪和传统灯箱的国家标准视力表测量差值的95%一致性界限分别为-0.25~0.20和-0.24~0.17。结论：智能视力表投影仪的可重复性较好,与传统灯箱的国家标准视力表的测量结果相比一致性较强,应用于临床工作中可提高视力筛查的效率并节省人力和物力。     

A new Gujarati language logMAR visual acuity chart: Development and validation

Aims:

Gujarati is the main spoken language of a large proportion of the population of India. The aim of this study was to develop and validate a new Minimum Angle of Resolution (logMAR) visual acuity chart in the Gujarati language.

Materials and Methods:

A new Gujarati visual acuity chart was designed to logMAR specifications using Gujarati optotypes experimentally selected to have similar relative letter legibility under spherical and cylindrical defocus. The chart validation study was carried out using 153 adult subjects in a large clinical setting in India. Subjects who were literate in English and Gujarati participated in the study. Visual acuity was measured with the new Gujarati logMAR chart and a modified Early Treatment of Diabetic Retinopathy Study-(m-ETDRS) logMAR chart. The method of presentation was randomized between the charts. Repeat visual acuity was measured on a subsequent day with a second version of the Gujarati logMAR chart.

Results:

The Gujarati chart correlated highly with the m-ETDRS logMAR chart (r² = 0.974). The mean visual acuity difference (Gujarati – m-ETDRS logMAR) was equal to three letters (–0.06 logMAR). The Gujarati logMAR chart also proved to be highly repeatable (r² = 0.994, test-retest) with 95% CI of ± 0.04 logMAR.

Conclusions:

The new Gujarati logMAR visual acuity chart provides a valid and repeatable tool for the measurement of visual acuity in native Gujarati language speakers.     

Validation of printed and computerised crowded Kay picture logMAR tests against gold standard ETDRS acuity test chart measurements in adult and amblyopic paediatric subjects

Aims

The impression exists that picture acuity scores may overestimate function when subjects are switched to letter charts. This has not been systematically investigated. The aims of this study were to validate both printed crowded Kay picture (pCKP) and computerised CKP (cCKP) logMAR test acuity measurements against gold standard ETDRS letter chart scores.

Methods

A total of 30 adult subjects with various ophthalmic disease and 40 amblyopic children underwent test and re-test visual acuity measurements using the ETDRS chart, the pCKP logMAR test, and the cCKP acuity scores taken, using the COMPlog visual acuity measurement system. Bland and Altman methods were employed.

Results

Computerised and printed Kay picture acuity scores agreed well. Both Kay picture test measurements were systematically biased when compared with ETDRS chart measurements. No significant proportional bias was found. The test retest variability (TRV) of all three tests was found to be similar between ±0.14 and 0.16 logMAR in both groups.

Conclusions

All three tests were similarly replicable and computerised Kay pictures appear to be a valid alternative to hard copy Kay pictures. Kay picture acuity measurements were systematically biased when compared with the gold standard ETDRS. Measurement error means that differences of up to 0.16 logMAR may be observed in clinically stable patients when re-measured using the same technique. A combination of TRV and systematic bias can however lead to differences of up to 0.40 logMAR in stable amblyopic patients when switched from CKPs to ETDRS chart acuity measurements.     

玻璃体切除术治疗眼后段外伤患者的临床分析

目的:评估眼后段外伤患者的人口统计学规律,探讨玻璃体切除术治疗的术后视觉效果,并比较术前和术后变量对术后视觉的影响.方法:选取2014-03/2015-06我院收取的90例90眼行玻璃体切除术的眼后段外伤患者作为研究对象进行回顾性分析.记录患者的年龄、性别、视力、创伤发生地点、解剖学位置、损伤属性、伤口长度、传入性瞳孔障碍的发生、手术时间等信息.使用眼外伤评分(OTS)对患者的视力进行评价.所有患者均随访6 mo以上.结果:所有入选患者均获得182~240(中位数198)d随访.所有患者中男77例77眼,女13例13眼,平均年龄32.7±15.8岁.47例47眼(52%)患者的创伤发生在工作场所,14例14眼(16%)发生在家庭.患者平均视力(LogMAR)从术前(2.36±0.72)到术后(1.50±1.14)得到明显改善.术前患者23例23眼的视力好于2.0,这些患者的术后视力改善显著优于术前视力较2.0差的患者,差异有统计学意义(P<0.01).早期手术组(<7d)与延迟手术组(>7d)相比视力改善值无显著统计学差异(P>0.05).损伤发生在Ⅰ区和Ⅱ区的患者术后视力无显著统计学差异(P>0.05),但Ⅲ区损伤患者的术后视力显著差于Ⅰ区和Ⅱ区患者,差异有统计学意义(P<0.05).发生传入性瞳孔障碍的患者术后视力更差,差异有统计学意义(P<0.05).不同OTS评分患者相比,术前、术后视力及术前术后视力差均具有显著统计学差异(P<0.01).结论:眼后段损伤更易发生于40岁以下的男性,且发生地点多为工作地.患者的术后视力与传入性瞳孔障碍、OTS评分、视力损伤区域相关,与手术时机无关.     

低浓度阿托品联合角膜塑形镜治疗青少年中低度近视的疗效

目的：分析角膜塑形镜联合低浓度阿托品对青少年中低度近视的控制效果。

方法：选取2016-01/06我科收治的中低度近视青少年患者76例152眼,按照自愿原则分为角膜塑形组36例72眼与角膜塑形镜联合低浓度阿托品组40例80眼(联合组),两组患者均配戴角膜塑形镜,联合组加用0.1g/L阿托品滴眼液点眼,均随访1a,检查戴镜前后裸眼视力、屈光度、眼轴长度、眼压、泪膜功能及角膜各参数的变化,统计并发症发生率。

结果：戴镜前、戴镜1a两组裸眼视力、屈光度、眼轴长度、眼压比较无差异(P>0.05),联合组戴镜前、戴镜1a裸眼视力变化幅度高于角膜塑形镜组,屈光度及眼轴长度差值低于角膜塑形镜组(P<0.05); 戴镜前,两组患者泪膜脂质层厚度(LLT)、客观散射指数(OSI)、泪膜破裂时间(BUT)比较无差异(P>0.05),戴镜1a,联合组LLT、BUT高于角膜塑形镜组,OSI低于角膜塑形镜组(P<0.05); 戴镜前,两组患者角膜曲率、角膜厚度、前房深度比较无差异(P>0.05),戴镜1a,联合组角膜曲率、角膜厚度、前房深度变化幅度均低于角膜塑形镜组(P<0.05); 两组患者并发症发生率比较无差异(P>0.05)。

结论：角膜塑形镜联合低浓度阿托品可改善青少年中低度近视患者裸眼视力,控制屈光度、眼轴增长,对角膜形态及泪膜功能无明显负面影响,安全性高。     

Comparison of VEP with contrast sensitivity and other measurements of central visual function

Purpose: In order to evaluate alternative visual acuity testing techniques, especially to discriminate between small changes and for high visual acuity, we conducted a study covering several state‐of‐the‐art techniques. Methods: In this cross‐sectional study, a homogeneous cohort of healthy and young patients (n = 33; 66 eyes) underwent ETDRS vision acuity (VA) testing, testing for contrast sensitivity (CS), VA determination with spatial frequency sweep visual evoked potentials (VEP) and a series of examinations of perifoveal retinal nerve fibre layer thickness (RNFLT) using Spectralis SD‐OCT. To simulate the effect of artificial media opacity, CS, and VEP were repeated with Bangerter foils. Results: We found that Bangerter foils can be used to reduce VA effectively measured by VA testing and VEP VA. CS correlated significantly with VA (correlation coefficients ranging from 0.54 to 0.77). VEP may be used to estimate VA; nevertheless, we found no significant correlation. RNFLT did not correlate significantly with VA. Conclusion: CS seems to correlate well with VA when used for high VA. All other used examinations seem to have difficulties distinguishing between small differences in VA or when the VA is high.     

近视性离焦对静态视力和动态视力的影响

背景光学离焦对静态视力能产生明显的影响,但是对动态视力的影响尚未见报道。目的研究近视性离焦对静态视力和动态视力影响的差异及其机制。方法研究纳入40名志愿者,包括20名平均年龄（27．40±1．64）岁的成人和20名平均年龄（11．70±1．49）岁的儿童。受检眼排除眼科疾患,最佳矫正视力≥1．0D,散光≤0．75D,双眼屈光参差〈1．50D。受检眼在远用屈光全部矫正的基础上分别加戴＋1．00、＋1．50、＋2．00、＋2．50D的正透镜进行离焦,使用自制的DVA-I动态视力测试仪和静态视力表测试受试者的动态视力和静态视力。结果成人组和儿童组的静态视力和动态视力均随着离焦度的增加而下降,4种离焦度的总体差异均有统计学意义（F=506．907,P=0．000）;成人组和儿童组在各离焦度的动态视力与静态视力间的比较差异均无统计学意义（P〉0．05）;线性回归分析表明,静态视力或动态视力与离焦度间均呈阳性相关（R2=0．819,t=26．720,P=0．000;R2=0．826,t=27．420,P=0．000）;离焦度与静态视力的斜率和截距均明显陡于离焦度与动态视力的斜度和截距（F=34．180,P=0．000;F=1005．560,P=0．001）。结论等量离焦对静态视力和动态视力的影响不同,推测动态视力不仅与屈光系统有关,还可能与其他影响因素有关。     

Evaluation of a New Method to Track Changes in Vision at Home for Children Undergoing Amblyopia Treatment

Purpose:A new amblyopia tracker app has been designed to provide parents with a method of monitoring a child’s vision by presenting a single optotype size that the tester moves to identify the furthest distance the optotypes can be seen. The aim of this study is to evaluate this methodology in adults, comparing the findings to visual acuity (VA) measured with the iSight app and to determine the test retest variability.Methods:Adults, aged 18–39 years, with no known eye condition and VA ≤ 0.7 logMAR were recruited. Bangerter filters were used to simulate amblyopia, where VA was reduced below 0.0 with an interocular difference of at least 0.2 logMAR. Testing for both apps was performed monocularly, with the test order being randomised.Results:Data from 32 subjects were analysed. For the test retest variability analysis, paired t-tests showed no statistically significant difference between the tests for either eye, either app or the interocular acuity difference (p > 0.3 in all cases). Bland Altman plots showed similar limits of agreement between the two apps. When comparing measurements between the apps there was no statistically significant difference on the first or second test, either eye or the interocular acuity difference (p > 0.5 in all cases).Conclusion:The results support the theory that changing distance is a valid method of assessing VA as the measurements agree well with the standard approach of reducing optotype size. Test retest variability is similar between the two apps and there is good agreement between the measurements.     

两种回归方法推算扫描视觉诱发电位客观推断视力的比较

背景扫描视觉诱发电位（SVEP）是一种客观视力的检测方法,虽然SVEP客观推断视力与主观视力之间存在着明显的相关性,但是两者之间并不完全吻合。研究显示,改进SVEP客观推断视力的推算方法可以提高推断视力的准确性。目的研究SVEP客观推断视力两种推算方法,即振幅-空间频率（A—SP）回归方法与振幅一视角对数（A-logVA）回归方法在客观视力评估中的准确性,探讨影响SVEP客观推断视力准确性的因素。方法对64例具有不同视力的113眼进行SVEP检测、主观小数视力和LogMAR视力检测,分别计算A—SP回归方法推算出的小数视力和LogMAR视力及A．10gVA回归方法推算出的小数视力和LogMAR视力,并对检测结果行相关性分析。使用重庆国特公司GT-2000n型视觉电生理仪检测SVEP,选用0．99～12．89cpd的10个空间频率水平正弦光栅连续刺激视网膜,经离散傅里叶分析获得A—SP回归曲线和A—logVA回归曲线,并将相关直线外推至0振幅处,获得SVEP客观推断视力。结果在小数视力评价系统中,A—SP回归方法和A-logVA回归方法推算出的回归线相关指数分别为0．663和0．705,主观小数视力与由A-SP回归方法推算所得的小数视力间呈正相关（r=0．620,P〈0．01）,主观小数视力与由A—logVA回归方法推算所得的小数视力间呈正相关（r=0．540,P〈0．01）。SP小数视力与VA小数视力间差异有统计学意义（Z=-8．688,P〈0．01）;在LogMAR视力评价系统中,A-SP回归方法和A—logVA回归方法推算出的回归线相关指数分别为0．733和0．715,主观LogMAR视力与由A-SP回归方法推算所得的LogMAR视力间呈正相关（r=0．710,P〈0．01）,主观LogMAR视力与由A-logVA回归方法推算所得的LogMAR视力间呈正相关（r=0．700,P〈0．01）。两种推算方法获得的LogMAR视力间差异有统计学意义（Z=-8．748,P〈0．01）。不同性别、眼别、病种以及年龄段中VALogMAR视力测试值的偏差差异均无统计学意义（χ2=2．171,P=0．338;χ2=0．976,P=0．614;χ2=6．032,P=0．420;χ2=14．720,P=0．257）。结论SVEP是检测客观视力较为有效的方法。但SVEP变异较大,就目前检测技术的稳定性与准确性而言,A—logVA回归方法推算出的客观视力较A—SP回归方法准确。     

玻璃体腔注射康柏西普联合23G微创玻璃体切割术治疗PDR

目的：探讨玻璃体腔注射康柏西普联合23G微创玻璃体切割术治疗对增殖性糖尿病视网膜病变(PDR)患者视网膜出血、视网膜增殖及视力预后的影响。

方法：将我院收治的56例56眼PDR患者分为康柏西普联合微创玻璃体切割术(pars plana vitrectomy,PPV)组和PPV组,各28例,康柏西普组给予玻璃体腔内注射康柏西普+23G微创玻璃体切割术,PPV组仅给予23G微创玻璃体切割术,比较两组手术时间、视网膜出血、视网膜增殖、视力等情况。

结果：康柏西普联合PPV组手术耗时及术中出血量均明显低于PPV组(P<0.05); 康柏西普联合PPV组术后视力、黄斑厚度均显著优于PPV组(P<0.05); 康柏西普联合PPV组术后视网膜出血评分、视网膜增殖评分、玻璃体再次出血率及血管内皮生长因子(VEGF)水平均显著低于PPV组(P<0.05)。

结论：玻璃体腔注射康柏西普联合23G微创玻璃体切割术治疗PDR不仅能有效缩短手术时间,减少术中视网膜出血和术后再出血,减轻视网膜增殖,还有助于患者术后视力恢复。     

A new method of extrapolating the sweep pattern visual evoked potential acuity

Purpose In order to compare the amplitude-spatial frequency (A-SP) regression method with amplitude-logVA (A-logVA) regression methods in extrapolating the sweep pattern visual evoked potential (SPVEP) acuity. Methods We measured SPVEPs in 21 children and three adults using sinusoidally-modulated horizontal gratings as stimuli. The responses were averaged and displayed through discrete Fourier transformations. SPVER acuity was then estimated by using both the SPVEP amplitude- spatial frequency function (A-SP function regression method) and the SPVEP amplitude-log visual-angle function (A-logVA function regression method). Furthermore, the Bailey Lovie logMAR chart was employed to define visual acuity. Curve estimates were calculated to derive a correlation index (R) for each method. Results There are significant differences (t = 2.71, P < 0.05) between the correlation indices of curves obtained using the A-logVA function (logarithmic model, 0.95 +/- 0.01) and that obtained by the A-SP function (inverse model, 0.92 +/- 0.02). The overall correlation coefficient (r) between logMAR acuity and acuity calculated by the A-logVA regression method was 0.32 (P < 0.05). The overall correlation coefficient (r) between logMAR acuity and acuity calculated by the A-SP regression method was 0.41 (P < 0.05). Paired t-tests show that SPVEP acuity from the A-logVA function was not significantly different from acuities of the logMAR function (t = 1.77, P = 0.09). The difference in their mean values is 0.14 +/- 0.08. However, SPVEP acuity calculated using the A-SP function regression method is significantly different from the acuity calculated from the logMAR function (t = 10.09, P < 0.01). The difference in their mean values is 0.41 +/- 0.04. Conclusions The amplitude-logVA function regression method is more accurate in estimating SPVEP acuity in normal subjects with good visual acuity.     

Pars planitis: a comparison of childhood onset and adult onset disease

Purpose : To compare the symptoms, visual acuities and complications found in childhood onset pars planitis, with those seen in adult onset disease. Method : The records of 26 patients (52 eyes) with idiopathic pars planitis seen at a tertiary care clinic were reviewed. The study design allowed comparison of follow‐up visual acuities for the adult onset and childhood onset groups at 2 years and 5 years from the time of initial diagnosis. Results : The visual acuity at the time of initial diagnosis, at 2 years’ follow up and at 5 years’ follow up was worse for children than for adults, but this difference only reached statistical significance at 2 years’ follow up (6/10 vs 6/7; P = 0.026). When looking at correlation coefficients between age and acuity, the same trend was observed at all time intervals, only reaching statistical significance with initial visual acuities (r = 0.32; P = 0.019). Adults had a tendency to complain more at presentation of blurred vision and floaters than children. Complication rates were similar for both groups. Conclusion : The study presents data supporting the idea that patients presenting with idiopathic pars planitis in childhood have a worse visual acuity both at initial diagnosis and at follow up than those presenting in adulthood. This is a long‐suspected finding that has not previously been demonstrated.