屈光参差儿童单眼配戴角膜塑形镜后调节功能的变化

目的：观察屈光参差儿童单眼配戴角膜塑形镜后双眼调节功能的变化,探讨调节在角膜塑形镜控制近视进展中的机制。

方法：前瞻性自身对照研究,对2016-09/2018-09在我院门诊就诊的屈光参差儿童单眼配戴角膜塑形镜的青少年22例44眼,将配戴角膜塑形镜的眼作为戴镜组,未作处理的另一眼作为未戴镜组。戴镜眼组22眼,等效球镜度-2.75±1.16D; 未戴镜眼组22眼,等效球镜度-0.10±0.32D。观察戴镜前和戴镜12mo后双眼屈光度差值、单眼调节幅度、调节灵敏度和调节反应的变化情况。

结果：戴镜组戴镜前的调节幅度和调节灵敏度低于未戴镜组(P<0.01),调节滞后高于未戴镜组(P<0.05)。戴镜组配戴12mo后的单眼调节幅度15.63±1.66D高于戴镜前11.25±3.15D(t=3.63,P<0.01),与未戴镜组无差异(t=0.75,P=0.46)。戴镜组配戴12mo后的单眼调节灵敏度14.63±1.58cyc/min高于戴镜前9.25±3.38cyc/min(t=2.83,P=0.01),与未戴镜组无差异(t=0.38,P=0.71)。戴镜组配戴12mo后的调节滞后0.62±0.29D较戴镜前1.35±0.26D减少(t=2.57,P=0.02),与未戴镜组无差异(t=0.61,P=0.55)。戴镜12mo后,未戴镜组的平均屈光度为-0.75±0.35D,戴镜组屈光度增长了-0.15±0.22D(t=2.90,P<0.01),未戴镜组屈光度增长了-0.65±0.39D(t=4.24,P<0.01),两组间屈光度的变化差值有差异(t=5.30,P<0.01)。未戴镜组12mo前后调节功能的变化无差异(P>0.05)。

结论：屈光参差儿童单眼配戴角膜塑形镜后戴镜眼的调节功能较戴镜前明显改善,且与对侧眼一致,戴镜眼的屈光状态更稳定,未戴镜眼逐渐呈现轻度近视屈光状态,但调节功能未出现明显变化。     

儿童屈光不正与各屈光参数关系

目的：研究眼轴、角膜屈光力、晶状体屈光力与儿童屈光不正的关系。

方法：通过睫状肌麻痹检影验光及光学生物测量仪(IOL-Master)获得44例88眼的屈光不正度数、眼轴、角膜屈光力、前房深度等参数,经计算得到晶状体度数。按屈光不正度数分为远视组、正视组、近视组,直线相关与回归比较年龄和屈光不正与各屈光参数之间的关系。

结果：受试者44例88眼,平均年龄9.04±2.39岁,等效球镜(SE)-3.50～+8.75D; 远视组眼轴比近视正视组短(P<0.05),远视组晶状体屈光力明显低于近视正视组(P<0.05),三组间角膜屈光力和前房深度无明显差别。本研究发现年龄与等效球镜(SE)之间成负相关; 眼轴与年龄成正相关; 年龄与晶状体屈光力成正相关; SE与眼轴成负相关; SE与晶状体屈光力有负相关关系。

结论：儿童随年龄增长,SE向近视发展,眼轴变长,晶状体屈光力增强; SE越偏远视,眼轴越短、晶状体屈光力越弱。     

角膜塑形镜对青少年近视患儿正相对调节力的影响

目的：观察配戴角膜塑形镜对于青少年近视患儿正相对调节力(PRA)改变的影响。

方法：回顾性病例分析。分析2016-09/2017-12间在我院视光科门诊初次就诊的青少年近视性屈光不正患儿122例244眼。其中选择角膜塑形镜矫正者63例(塑形镜组),选择框架眼镜矫正者59例(框架眼镜组),比较两组患儿治疗前及治疗6mo时双眼PRA的改变情况。

结果：治疗前塑形镜组PRA值-0.83±0.23D,框架眼镜组-0.77±0.24D(t=-1.457,P>0.05)。治疗前塑形镜组眼轴24.84±0.90mm,框架眼镜组24.78±0.86mm(t=0.550,P>0.05)。治疗6mo时塑形镜组PRA值-2.27±0.37D,与治疗前有差异(t=37.070,P<0.001)。治疗6mo时框架眼镜组PRA值-0.83±0.24D,与治疗前无差异(t=1.565,P>0.05)。治疗后塑形镜组PRA优于框架组(t=-25.271,P<0.001)。治疗6mo时塑形镜组眼轴24.86±0.91mm,与治疗前24.84±0.90mm有差异(t=-2.453,P<0.05)。治疗6mo时框架眼镜组眼轴24.97±0.86mm,与治疗前24.78±0.86mm有差异(t=39.135,P<0.001)。治疗6mo时两组眼轴无差异(t=-0.932,P>0.05)。

结论：青少年近视患儿配戴塑形镜相比配戴框架眼镜在治疗6mo时可明显提高其双眼PRA储备,但两者眼轴改变差异不明显。     

配戴多焦点硬性角膜接触镜对近视患者双眼视功能的影响

目的：探讨多焦点设计的硬性角膜接触镜对近视患者双眼视功能的影响。

方法：自身前后对照研究。于2020-07/08在川北医学院招募近视学生15人作为试验者,试验者首先配戴框架眼镜行双眼视功能检查,然后分别配戴单焦点与多焦点硬性角膜接触镜(间隔1wk),每种镜片配戴2wk后行双眼视功能检查。采用单因素方差分析比较多焦点硬性角膜接触镜(MFRGP)、单焦点硬性角膜接触镜(SVRGP)和框架眼镜双眼视功能的差异。

结果：三种镜片立体视、远距水平隐斜、远距正融像性聚散、远距负融像性聚散、近距正融像性聚散、聚散灵活度、集合近点、调节幅度、调节灵活度、负相对调节比较均无差异(P>0.05)。与框架眼镜相比,配戴MFRGP近距水平隐斜、近距负融像性聚散、调节滞后、正相对调节增大,AC/A降低(P=0.023、0.048、0.001、0.013、0.046); 与SVRGP相比,MFRGP近距水平隐斜、调节滞后、正相对调节增大,AC/A降低(P=0.014、<0.001、0.001、0.009)。

结论：配戴MFRGP会引起近距水平隐斜、调节滞后、正相对调节增大和AC/A降低,这些变化可能对配戴者近距离用眼产生一定影响,在临床应用中要考虑这些预期的变化,以便正确评估和管理患者。     

学龄前远视性屈光不正儿童眼球生物学参数分析

目的：分析学龄前远视性屈光不正性儿童(3～6岁)眼球生物学参数及其与屈光度的关系。

方法：收集2016-01/2018-12我院眼科门诊就诊的学龄前远视性屈光不正儿童203例405眼,睫状肌麻痹状态下行检影验光,根据双眼等效球镜度将患儿分为轻度远视组、中度远视组、高度远视组。眼科A型超声仪测量眼球相关参数,收集前房深度(ACD)、晶状体厚度(LT)、玻璃体腔深度(VITR)和眼轴长度(AL),自动验光仪检查水平和垂直角膜屈光力(K1、K2)。并分析各组眼球生物学参数与屈光度的关系。

结果：学龄前远视性屈光不正性儿童平均ACD为3.08±0.38mm,LT为3.91±0.34mm,VITR为14.53±1.85mm,AL为21.45±1.01mm,K值为43.34±1.70D。AL、ACD、LT和VITR在三组间均有差异(P<0.05); 而K值在各组间无差异(P>0.05)。远视屈光度与AL和VITR呈负相关(P<0.01),与ACD、LT、K值无相关性(P>0.05)。

结论：AL的变化是影响远视性屈光不正性学龄前儿童屈光状态的最主要因素,表现为远视屈光程度越高,AL越短,玻璃体腔越浅,协同参与屈光状态的变化,而远视程度与ACD、LT和K值无相关性。学龄前儿童远视屈光不正以轴性屈光不正为主。     

两种屈光矫正方式对青少年近视患者调节反应的影响

目的：观察并比较青少年近视患者在配戴角膜塑形镜和配戴框架眼镜后调节反应的变化情况。

方法：选取10～16岁中低度青少年近视患者120例240眼,根据屈光矫正方式不同分为试验组(配戴角膜塑形镜)和对照组(配戴单光框架眼镜),试验组和对照组各60例120眼,随访并比较两组患者戴镜前和戴镜后1、3、6、12mo的调节反应。

结果：共有113例患者226眼完成该研究,其中试验组54例108眼,对照组59例118眼。两组患者戴镜前和戴镜后的调节反应均表现为调节滞后,且调节滞后量随着配戴时间的延长逐渐下降; 试验组和对照组在戴镜前和戴镜后1、3、6、12mo的调节滞后量分别为(1.22±0.47、0.91±0.39、0.77±0.40、0.65±0.32、0.51±0.22)D、(1.23±0.48、1.05±0.41、0.90±0.49、0.83±0.46、0.69±0.33)D; 测量时间对各组调节滞后量的影响均有统计学意义(F=195.229、142.361、 323.484,P<0.05),组别与测量时间的交互作用对调节滞后量的影响也有统计学意义(F=11.222,P<0.05),但眼别与测量时间的交互作用对调节滞后量的影响均没有统计学意义(F=0.025、0.023,P>0.05); 试验组和对照组戴镜前调节滞后量的差异无统计学意义(t=-0.07,P>0.05),试验组戴镜后1、3、6、12mo的调节滞后量均小于对照组,差异有统计学意义(t=-2.587、 -2.241、 -3.522、-4.587,P<0.05)。

结论：青少年近视患者配戴角膜塑形镜和配戴框架眼镜都能改善调节反应,减少调节滞后量,但配戴角膜塑形镜的效果要优于配戴框架眼镜。     

手持自动验光仪在学龄前儿童验光中的应用

目的：评估HAR-800手持验光仪对学龄前儿童屈光检查的准确性。

方法：对173例学龄前儿童进行检影验光,首先行HAR-800手持验光仪检查(试验组),然后应用阿托品眼膏进行扩瞳检影验光(对照组),比较两种检影验光的屈光差异。

结果：试验组球镜为1.59±0.61D,对照组为3.15±0.72D,两者有显著统计学差异(t=-82.89, P<0.01),且具有相关性(r=0.87,P<0.01)。试验组散光为-0.62±0.51D,对照组为-0.48±0.55D,两者有显著统计学差异(t=-6.97,P<0.01),且具有显著相关性(r=0.76,P<0.01)。

结论：HAR-800手持验光仪不能替代阿托品检影验光,但其结果可以反映学龄前儿童的屈光状况。     

SMILE手术中角膜切削厚度精确性的研究

目的：评估不同程度近视患者SMILE术前预估角膜切削厚度与术后实际角膜切削厚度的差异,探究SMILE术中角膜基质切削厚度的精确性。

方法：前瞻性研究。收集2017-01/2019-08在我院行SMILE手术的近视患者143例234眼,根据术前等效球镜度分为低(-0.50～-3.00D,78眼)、中(>-3.00～-6.00D,78眼)、高(>-6.00D,78眼)度近视组,观察三组患者手术前后视力和等效球镜度,并分别于术前和术后1mo采用Pentacam眼前节综合分析系统测量中央角膜厚度,比较术前预估角膜切削厚度与术后1mo实际切削厚度的差异,探讨SMILE术中不同屈光状态角膜基质切削厚度的精确性。

结果：术后1mo,所有患眼裸眼视力均达0.8以上,98.3%患眼裸眼视力达1.0以上。所有患者术后1mo角膜平均实际切削厚度低于平均预估切削厚度(84.92±23.15μm vs 100.07±26.83μm,P<0.01),平均切削差异值为15.15±10.34μm。低、中、高度近视组患者角膜实际切削厚度均低于各组预估角膜切削厚度(P<0.01),切削差异值分别为8.81±7.78、15.59±9.27、21.05±10.03μm。术前,本研究纳入患者平均等效球镜度为-4.85±2.15D,术前等效球镜度与切削差异值之间具有直线回归关系(Y=-2.2495X+3.9287,R²=0.1589),等效球镜度数越大,切削差异值越大(t=-6.620,P<0.001)。

结论：SMILE手术的角膜基质实际切削厚度低于预估切削厚度,且近视度数越高,切削差异越大,但术后屈光矫正效果理想,术中角膜切削厚度的差异并不影响屈光矫正手术的精确性。     

近视眼手术人群角膜直径的分析

目的：测量近视眼手术人群的角膜直径,探讨不同性别、眼别角膜直径的差别及角膜直径与等效球镜度数之间的相关性。

方法：对2013-03/08来我院近视门诊行准分子激光手术的近视眼126例252眼,男48例96眼,女78例156眼, 年龄18～45(平均24.23±5.35)岁,应用IOL Master测量角膜直径\〖white-to-white(WTW)\〗距离。对252眼都采用NIDEK RT-2100综合验光仪进行主觉验光,并换算成等效球镜\〖Spherical equivalent(SE)\〗,按照等效球镜度数分成3组：轻度近视(-3.00D结果：全部病例角膜直径平均值为11.52±0.41mm,其中男性角膜直径11.60±0.35mm,女性11.43±0.36mm,性别间角膜直径有统计学意义( t=0.021,P=0.009); 右眼平均角膜直径(11.53±0.40mm)与左眼(11.51±0.42mm)比较无显著统计学差异(t=-0.115,P=0.912); 低度、中度和高度近视者的角膜直径的平均值分别为11.59±0.39、11.48±0.40、11.45±0.41mm,角膜直径与屈光度间呈负相关性(R²=-0.001,P=0.001),且三组近视患者角膜直径之间存在显著统计学差异(F=4.487, P=0.004)。

结论：近视眼手术人群中男性角膜直径大于女性; 近视程度越高,角膜直径越短。     

不同程度近视青少年儿童双眼视功能的差异

目的通过比较不同程度近视儿童双眼协动参数的差异性及其与近视程度相关性,进一步探索近视发展的原理。方法横断面研究。研究对象包括128例7～14岁近视青少年儿童,根据等效球镜度分为低度近视组（-0.50～-3.00 D）、中度近视组（-3.25～-6.00 D）和高度近视组（>-6.00 D）。双眼协动参数测量包括远距及近距水平聚散力,远距及近距水平隐斜,梯度性调节性集合与调节的比率（AC/A比率）。采用单因素方差分析和卡方检验对3组数据进行分析。结果在融像性聚散范围中,远距散开力的破裂点、近距散开力的恢复点、远距集合力的恢复点、近距集合力的模糊点及破裂点随近视程度加深而减小（F=3.271、3.579、4.931、6.507、4.887,P<0.05）,其余参数的差异无明显统计学意义（P>0.05）;在隐斜视类型的构成比中,远距及近距隐斜类型构成比例的差异在3组中无明显统计学意义（P>0.05）,总体上近距内隐斜构成比例高于远距内隐斜（χ²=6.609,P<0.05）;梯度性AC/A随近视程度的增加而增加（F=3.625,P<0.05）,其中高度近视组明显高于低度近视组（P<0.05）。结论随着青少年儿童近视程度的增加,融像性聚散范围减少,梯度性AC/A比率增高。近视儿童表现出的近距内隐斜可能与近视发展相关。     

近视儿童配戴单光镜后的周边屈光研究

目的:研究近视儿童配戴单光镜后对周边视网膜屈光状态的影响。方法:采用自身对照研究。入选10～15岁近视儿童48例,睫状肌麻痹下使用Grand Seiko WAM5500型红外验光仪测量右眼视网膜中心凹0°以及鼻颞侧10°,20°,30°的屈光值,分别在裸眼和配戴单光眼镜时测量。结果:近视儿童的平均屈光度为-3.99±1.22D,相对周边屈光度在水平视野上为远视性离焦。随着注视角度的增大,相对远视性离焦量增大。戴镜后的相对周边远视性离焦量较裸眼时增大(P<0.01)。戴镜前后的J180及J45相比较无统计学差异。结论:近视儿童配戴单光镜后周边视网膜远视性离焦量增大。根据周边视网膜的聚焦状态改进镜片的设计可能会成为近视矫正的新思路。     

Spectacle lens compensation in the pigmented guinea pig

When a young growing eye wears a negative or positive spectacle lens, the eye compensates for the imposed defocus by accelerating or slowing its elongation rate so that the eye becomes emmetropic with the lens in place. Such spectacle lens compensation has been shown in chicks, tree-shrews, marmosets and rhesus monkeys. We have developed a model of emmetropisation using the guinea pig in order to establish a rapid and easy mammalian model. Guinea pigs were raised with a +4D, +2D, 0D (plano), −2D or −4D lens worn in front of one eye for 10 days or a +4D on one eye and a 0D on the fellow eye for 5 days or no lens on either eye (littermate controls). Refractive error and ocular distances were measured at the end of these periods. The difference in refractive error between the eyes was linearly related to the lens-power worn. A significant compensatory response to a +4D lens occurred after only 5 days and near full compensation occurred after 10 days when the effective imposed refractive error was between 0D and 8D of hyperopia. Eyes wearing plano lenses were slightly more myopic than their fellow eyes (−1.7D) but showed no difference in ocular length. Relative to the plano group, plus and minus lenses induced relative hyperopic or myopic differences between the two eyes, inhibited or accelerated their ocular growth, and expanded or decreased the relative thickness of the choroid, respectively. In individual animals, the difference between the eyes in vitreous chamber depth and choroid thickness reached ±100 and ±40 μm, respectively, and was significantly correlated with the induced refractive differences. Although eyes responded differentially to plus and minus lenses, the plus lenses generally corrected the hyperopia present in these young animals. The effective refractive error induced by the lenses ranged between −2D of myopic defocus to +10D of hyperopic defocus with the lens in place, and compensation was highly linear between 0D and 8D of effective hyperopic defocus, beyond which the compensation was reduced. We conclude that in the guinea pig, ocular growth and refractive error are visually regulated in a bidirectional manner to plus and minus lenses, but that the eye responds in a graded manner to imposed effective hyperopic defocus.     

配戴离焦RGPCL对高度近视儿童角膜屈光力及散光量的影响

目的：对比观察高度近视儿童配戴离焦硬性透气性角膜接触镜(RGPCL)前后角膜屈光力改变,并分析配戴后镜片对角膜屈光力及散光量的影响。

方法：自身前后对照研究。收集2019-06/2020-06在西安市第一医院眼视光中心就诊并验配离焦RGPCL的8～12岁高度近视儿童30例60眼。使用TMS-4N角膜地形图仪测量基线及戴镜0.5、1a时戴镜状态下角膜切向屈光力,分析角膜鼻侧(N)、颞侧(T)、上方(S)和下方(I)角膜最大屈光力值及中央顶点处角膜屈光力改变情况,同时以1mm为间隔采集前述4个方位角膜屈光力以及角膜顶点处屈光力,采集范围为1～4mm,分析戴镜前后各点位屈光力变化情况。戴镜0.5,1a时后要求停戴1wk后复测眼轴、屈光度和角膜地形图,分析戴镜后较基线时眼轴、等效球镜度、散光和角膜屈光力等改变情况。

结果：配戴离焦RGPCL时鼻侧(N)、颞侧(T)、上方(S)和下方(I)的角膜最大屈光力在0.5、1a时较戴镜前均显著增加,与角膜顶点处屈光力相比均表现为正相对屈光力,与戴镜前的负相对屈光力相比具有显著差异。在戴镜0.5、1a时复诊时戴镜状态下角膜相对周边屈光力朝正屈光力方向改变,除T1点位周边负屈光力增加外,其余各轴向各点位周边屈光力均显著增加。配戴0.5a后角膜陡K值变平0.11±0.10D,simK值减少0.20±0.18D,1a后角膜陡K值变平0.10±0.12D,平均K值变平0.02±0.05D,simK值减少0.16±0.13D。戴镜0.5、1a时后角膜平K较基线变化无差异。

结论：配戴离焦RGPCL状态下角膜最大屈光力较角膜顶点处均表现为正相对屈光力,且4条轴向上各点位角膜相对周边负屈光力均由负值转变为正值。戴镜1a内眼轴和等效球镜度均较基线时增加,而散光量减少,角膜屈光力呈陡K变平趋势。     

CRT与VST设计角膜塑形镜对低E值角膜形态近视的控制效果比较

目的：观察和分析配戴CRT与VST设计角膜塑形镜对低E值角膜形态控制青少年近视发展的有效性及安全性的对比研究。

方法：前瞻性研究，选取2020-01/2021-12于我院视光门诊就诊配戴角膜塑形镜的青少年近视患者100例100眼，取右眼数据用于研究。按等效球镜分低度近视组(-1.00--3.00 D)和中度近视组(-3.25--5.00 D)，各50例。组内采用随机数字表法分为CRT组和VST组，各25例。测量各组配戴前后裸眼视力、屈光度、眼轴(AL)、泪膜破裂时间(BUT)、角膜内皮细胞密度、角膜点染分级、镜片偏位情况、MRT 15°-30°处视网膜近视离焦量。随访1.5 a。

结果：低度近视中，CRT组和VST组配戴角膜塑形镜后裸眼视力各时间点无差异，中度近视数组塑形后裸眼视力CRT组优于VST组，两组1 d，1 wk的视力有差异(t=-9.474、-12.067，均P<0.01)，其他时间点两组均无差异。戴镜后6 mo，1.5 a，低度近视、中度近视中CRT组和VST组AL增加量均无差异，但CRT组比VST组增长少。两组戴镜后6 mo，1.5 a的双眼BUT及角膜内皮细胞密度均无差异。从两组的角膜损伤来看CRT组角膜损伤低于VST组，但无差异(Z=-1.803，P=0.071)，CRT组镜片偏位情况优于VST组(Z=-4.629，P<0.001)； MRT 15°-30°处视网膜近视离焦量，低度近视中两组无差异，中度近视中1、3、6 mo离焦量有差异(t=-3.949，P=0.008； t=-5.833，P<0.001； t=-6.231，P<0.001)，CRT组能产生更多的近视性离焦量。

结论：对于对低E值角膜形态的患者，CRT采用角膜8 mm处的矢高值来验配，不局限于角膜E值，塑形更快，塑形后裸眼视力更好，特别对于中度近视能获得更好的白天视力，从控制近视来看，CRT验配中抬高反转区(RZD)，产生小的中央光学区能产生更大的周边近视性离焦，但两组控制眼轴增长之间无明显差异。两组的角膜损伤少，对近视控制安全性一致。     

配戴角膜塑形镜和框架眼镜对近视儿童周边屈光度影响的随机对照临床试验

背景 临床实践发现角膜塑形镜具有延缓近视及眼轴长度进展的效果,但对于角膜塑形镜配戴的相关作用机制,特别是角膜塑型术对视网膜中心和周边的离焦作用机制尚不完全清楚. 目的 观察低中度近视儿童配戴角膜塑形镜和框架眼镜6个月后周边屈光度以及相对周边屈光度(RPR)的变化.方法 采用随机对照临床试验方法,于2014年6月至2015年1月在北京同仁眼科中心招募屈光度为-0.50～-6.00 D的低中度近视儿童100例,平均年龄(11.0±1.9)岁,均纳入右眼进行研究.受试者按入组顺序编号后由SAS统计软件PROC PLAN过程语句随机均分为角膜塑形镜组和框架眼镜组,每组50例50眼,戴镜时间均为6个月.采用开放视野红外自动验光仪分别测量戴镜前后中央0°、颞侧15°和30°、鼻侧15°和30°径线的屈光度,观察并比较各组受试眼戴镜前后周边屈光度和RPR(周边屈光度与中央屈光度差值)变化趋势. 结果 角膜塑形镜组和框架眼镜组受试者戴镜前屈光度分别为(-3.35±1.31)D和(-3.01±1.15)D,差异无统计学意义(P=0.201).角膜塑形镜组受试眼戴镜前鼻侧30°、鼻侧15°、中央0°、颞侧15°和颞侧30°径线周边屈光度分别为(-2.28±1.60)、(-3.28±1.41)、(-3.40±1.23)、(-3.38±1.12)和(-2.09±1.29)D,受试眼除颞侧30°外戴镜后6个月近视度数均下降,戴镜前后鼻侧30°、鼻侧15°、中央0°、颞侧15°屈光度变化值分别为(0.29±1.67)、(0.85±1.66)、(0.92±1.76)和(0.66±1.66)D,其中鼻侧15°、中央0°、颞侧15°与戴镜前相比差异均有统计学意义(均P＜0.05).框架眼镜组受试者戴镜前鼻侧30°、鼻侧15°、颞侧15°和颞侧30°径线周边屈光度分别为(-1.88±1.30)、(-2.66±1.18)、(-2.89±1.27)和(-1.94±1.31)D,戴镜后6个月上述各径线近视度数均增加,戴镜前后变化值分别为(-0.25±0.80)、(-0.43±0.67)、(-0.32±0.64)和(-0.22±0.75)D,与戴镜前比较差异均有统计学意义(均P＜0.05).角膜塑形镜组受试者戴镜前各径线RPR均为远视性离焦状态,戴镜后6个月颞侧15°和颞侧30°RPR变为近视性离焦状态.框架眼镜组受试者戴镜前各径线RPR均为远视性离焦状态,戴镜后各径线RPR均呈远视性离焦加深状态.结论 长期配戴角膜塑形镜能够使近视儿童的周边屈光度发生远视性漂移,视网膜周边呈现相对近视性离焦,而长期配戴框架眼镜则使周边屈光度发生近视漂移,视网膜周边远视性离焦加深.角膜塑形镜配戴可能通过改变周边屈光度而达到减缓近视进展的目的.     

周边视网膜相对屈光度与近视进展的关系

在正视眼或者低度远视眼中,周边视网膜呈相对远视屈光状态者比周边视网膜呈相对近视屈光状态者更容易发展为近视眼.正视眼周边视网膜呈轻度相对近视屈光状态,未矫正的远视眼周边视网膜呈稍大程度的相对近视屈光状态,未矫正的近视眼周边视网膜呈轻度相对远视屈光状态或比正视眼程度轻的相对近视状态.这两种观点已经被学者广泛接受.动物实验也证明异常视觉信号不仅能引起中央视网膜屈光不正,也能改变眼球后极部眼球形态和周边视网膜相对屈光不正的类型,并且黄斑切除并不影响正视化过程.相反,周边视网膜能单独调控眼球正视化过程并能对异常视觉信号起作用进而发展为各种屈光不正.临床研究表明,矫正视网膜周边远视性离焦的框架镜片对近视眼进展能起到一定的控制作用.虽然,周边视网膜远视性离焦是否促进近视进展的确切原因还不能肯定,但目前的研究倾向于认为两者之间可能有某种关系.     

Effectiveness of hyperopic defocus, minimal defocus, or myopic defocus in competition with a myopiagenic stimulus in tree shrew eyes

PURPOSE: To examine the ability of hyperopic defocus, minimal defocus, and myopic defocus to compete against a myopiagenic -5-D lens in juvenile tree shrew eyes. METHODS: Juvenile tree shrews (n > or = 5 per group), on a 14-hour lights-on/10-hour lights-off schedule, wore a monocular -5-D lens (a myopiagenic stimulus) over the right eye in their home cages for more than 23 hours per day for 11 days. For 45 minutes each day, the animals were restrained so that all visual stimuli were >1 m away. While viewing distance was controlled, the -5-D lens was removed and another lens was substituted with one of the following spherical powers: -5 D, -3 D (hyperopic defocus); plano (minimal defocus); or +3, +4, +5, +6, or +10 D (myopic defocus). Daily noncycloplegic autorefractor measures were made on most animals. After 11 days of treatment, cycloplegic refractive state and axial component dimensions were measured. RESULTS: Eyes with the substituted -5- or -3-D-lens developed significant myopia (mean +/- SEM, -4.7 +/- 0.3 and -3.1 +/- 0.1 D, respectively) and appropriate vitreous chamber elongation. All animals with the substituted plano lens (minimal defocus) during the 45-minute period showed no axial elongation or myopia (the plano lens competed effectively against the -5-D lens). Variable results were found among animals that wore a plus lens (myopic defocus). In 11 of 20 eyes, a +3-, +4-, or +5-D lens competed effectively against the -5-D lens (treated eye <1.5 D myopic relative to its fellow control eye). In the other eyes (9/20) myopic defocus was ineffective in blocking compensation; the treated eye became more than 2.5 D myopic relative to the control eye. The +6- and +10-D substituted lenses were ineffective in blocking compensation in all cases. CONCLUSIONS: When viewing distance was limited to objects >1 m away, viewing through a plano lens for 45 minutes (minimal defocus) consistently prevented the development of axial elongation and myopia in response to a myopiagenic -5-D lens. Myopic defocus prevented compensation in some but not all animals. Thus, myopic defocus is encoded by at least some tree shrew retinas as being different from hyperopic defocus, and myopic defocus can sometimes counteract the myopiagenic effect of the -5-D lens (hyperopic defocus). However, it appears that minimal defocus is a more consistent, strong antidote to a myopiagenic stimulus in this mammal closely related to primates.     

Effect of spectacle lenses designed to reduce relative peripheral hyperopia on myopia progression in Japanese children: a 2-year multicenter randomized controlled trial

Purpose

Novel spectacle lenses (MyoVision, Carl Zeiss) designed to reduce relative peripheral hyperopia have been developed and reported to be effective for preventing myopia progression in a subgroup of Chinese children. In this study we examined the efficacy of MyoVision lenses in Japanese children.

Study design

This was a multicenter prospective randomized double-blind placebo-controlled trial.

Method

We enrolled 207 participants (aged 6–12 years) with spherical equivalent refractions (SERs) ranging from ?1.5 to ?4.5 diopters (D) and with at least 1 myopic parent. The participants were randomized to receive either single vision lenses (SVLs) or MyoVision lenses and were followed up every 6 months for 2 years. The primary outcome was myopia progression evaluated by cycloplegic autorefraction, and the secondary outcome was elongation of axial length.

Results

A total of 203 children (98.1%) completed the follow-up. The mean adjusted change in SER was ?1.43 ± 0.10 D in the MyoVision group, which was not significantly different from that of the control group wearing SVLs (?1.39 ± 0.07 D) at the 24-month visit (P = .65). The adjusted axial length elongation was 0.73 ± 0.04 mm in the MyoVision group, which was not significantly different from that in the control group wearing SVLs (0.69 ± 0.03 mm) at the 24-month visit (P = .28).

Conclusion

The results of this clinical trial could not verify the therapeutic effect of MyoVision for slowing down myopia progression in Japanese children. Additional studies are needed to design lenses that can reduce peripheral hyperopic defocus individually and to examine the effectiveness of these lenses in preventing myopia progression.

     

Effects of continuous light on experimental refractive errors in chicks

It is possible to induce ametropias in young chicks either by depriving the developing eye of clear form vision with a translucent goggle or by defocusing the retinal image with convex or concave lenses. The refractive properties of the developing chick eye are also altered by raising young birds in a continuous light environment. The effects of superimposing form deprivation or defocus treatments on chicks raised in continuous light are unclear. Newly hatched (n = 31) chicks were raised for 2 weeks under continuous light while wearing either translucent goggles or + 10 or ? 10 diopter (D) lenses over one eye. Refractive states, corneal curvature and intraocular dimensions were measured periodically by retinoscopy, keratometry and A-scan ultrasound. The birds were sacrificed after 2 weeks and the eyes removed and measured with calipers. Under continuous light, all eyes treated with translucent goggle and ? 10D lens developed moderate myopia (? 2.6 ± 0.5 D and ? 1.4 ± 0.3 D, respectively) by day 4. The eyes treated with a + 10 D lens developed moderate hyperopia (+ 4.8 ± 0.5 D) at day 4. Corneal curvatures of all treated eyes were slightly, but significantly, larger than contralateral control eyes by day 4. After 2 weeks of goggle or lens application, all the treated eyes were hyperopic due to corneal flattening. But the eyes treated with a goggle or a ? 10 D lens still showed relative myopia compared to the fellow eyes (treated minus untreated = ? 3.8 ± 0.4 D and ? 2.8 ± 0.4 D, respectively), and the eyes treated with a + 10 D lens showed more hyperopia than fellow eyes (treated minus untreated = + 5.1 ± 0.6 D). Compared with the control eyes, the axial length (mainly vitreous chamber depth) was slightly, but significantly, increased in the eyes treated with a goggle or a ? 10 D lens, and the axial length decreased slightly in the eyes treated with + 10 D lens. The results suggest that form deprivation and retinal defocus (induced by ± 10 D lenses) could still induce experimental refractive errors (myopia and hyperopia) in chicks kept under continuous light, but the effects of form deprivation and retinal defocus were partially suppressed by continuous light.     

Peripheral optical quality and myopia progression in children

Background

To investigate the peripheral optical quality and its relationship with axial elongation, myopic progression in Japanese children.

Methods

Twenty-nine Japanese children, ages 10 to 12 years old, with baseline refraction from +0.75D to ?5.5 D, were included and followed for 9 months. The central and peripheral point spread functions (PSFs; 0°, 10°, 20°, 30° nasally) were obtained at 0.25 D steps around ±2.5 D of best-focus PSF (BF-PSF) using double-pass PSF system. Modulation transfer function (MTF) area of the BF-PSF was calculated from BF-PSF to represent the peripheral optical quality. Relative peripheral defocus (RPD), the refraction of anterior/posterior focal lines, MTF area, and their correlations with myopia progression were analyzed.

Results

The average refractive change in 9 months was ?0.5?±?0.8 D. The change in axial length was significantly positively correlated with the amount of myopic progression (P?=?0.0058) and RPD (P?=?0.0007, 0.0036 and 0.0040, at 10°, 20°, 30° respectively) at the initial visit, but did not correlate with the peripheral MTF area. Myopic progression of more than 0.5 D with axial elongation was observed in seven children (MP group). The RPDs at 20° and 30° in the MP group were significantly more hyperopic than in the non-MP group (P?=?0.002 and 0.007), whereas there was no significant difference in axial length, and central and peripheral MTF area between the MP and non-MP groups. MP group had more hyperopic focal lines compared with non-MP group at 20°and 30°.

Conclusion

These results suggest that the progression of axial myopia in children is associated with hyperopic RPD and refraction of focal lines, not with peripheral optical quality.