角膜塑形镜控制青少年单眼近视的临床观察

目的：观察角膜塑形镜控制青少年单眼近视的临床效果。

方法：选取2014-06/2016-03于我院视光门诊单眼验配角膜塑形镜的单眼近视患者56例112眼,将配戴角膜塑形镜的眼作为试验组,未作处理的另一眼作为对照组。观察戴镜前和戴镜12mo后屈光度、角膜曲率、眼轴长度变化情况。

结果：戴镜12mo后,试验组屈光度增加量(0.29±0.15D)与对照组(0.76±0.41D)差异显著(t=2.8631,P<0.001); 试验组水平角膜曲率变化量(0.27±0.11D)与对照组(0.20±0.14D)无差异(t=0.8204,P>0.05); 试验组眼轴长度增加量(0.14±0.10mm)与对照组(0.32±0.14mm)差异显著(t=2.7518,P<0.001)。

结论：角膜塑形镜可通过减缓眼轴增长来控制近视度数的增加,从而延缓近视的发展。     

近视儿童中心凹下脉络膜厚度的相关性

目的：研究不同近视程度儿童中心凹下脉络膜厚度(SFCT)变化及其影响因素。

方法：前瞻队列性研究。选取5～14岁的近视儿童患者45例89眼,并根据等效球镜度(SE)分为不同的屈光组,其中轻度组27眼,中度组42眼,高度组20眼。应用光学相干断层扫描仪的加强深度扫描模式(EDI-OCT)测量中心凹下脉络膜厚度(SFCT),比较近视各组间的SFCT变化规律,并对相关影响因素进行分析。

结果：轻度、中度和高度近视组SFCT分别为253.22±43.56、223.19±54.93、185.90±50.99μm(P<0.05); Pearson相关性分析发现：SFCT与SE、眼轴长度(AL)、视网膜神经纤维层(RNFL)厚度有明显相关性(r=0.430、-0.499、0.425,均P<0.001); 与K1、K2略相关(P<0.05)。近视各组间近视家族史构成比有差异(χ²=7.44,P<0.05)。

结论：儿童近视程度越深,SFCT越薄,AL与SFCT相关性略优于屈光度,且儿童近视程度与近视家族史有关。     

青少年近视配戴角膜塑形镜前后眼轴长度的变化

目的：观察青少年近视配戴角膜塑形镜前后眼轴长度的变化。

方法：选取2014-07/2017-10在西安交通大学第一附属医院眼视光中心配戴角膜塑形镜的8～16岁青少年近视102例为研究对象,观察其戴镜后1、2、3a眼轴变化情况,对研究对象的右眼数据进行统计分析。

结果：青少年近视102例配戴角膜塑形镜3a后,眼轴增长0.42±0.37mm,低、中、高度近视组眼轴分别增长0.65±0.35、0.32±0.37、0.30±0.29mm,高度近视组(夜戴角膜塑形镜联合白天全矫框架眼镜)眼轴增长最慢; 配戴时间与戴镜前屈光度、起始治疗年龄之间均存在交互作用(P<0.001); 而配戴时间和性别之间无交互作用(F=0.292,P=0.695),男、女性戴镜后的眼轴变化速率未见差异。

结论：低、中、高度近视青少年配戴角膜塑形镜后眼轴长度均有增长,高度近视青少年夜间配戴角膜塑形镜联合白天全矫框架眼镜眼轴增长速度慢于低中度近视者。     

角膜塑形镜治疗后光学区偏离中心对控制近视的影响

目的：观察和分析角膜塑形镜治疗后角膜形态的变化,评估角膜塑形镜治疗后光学区偏离中心对控制近视的影响。

方法：回顾性临床研究。对134例134眼近视患儿配戴角膜塑形镜矫治近视,平均年龄10.66±1.79岁, 均取右眼数据进行研究。分别在戴镜前及戴镜后3、6、12、18、24mo检查视力、眼轴和角膜地形图。使用SPSS19.0进行统计学分析。

结果：戴镜后3、6、12、18、24mo的光学区偏瞳孔中心距离分别为0.84±0.45、0.77±0.40、0.79±0.41、0.78±0.41、0.79±0.42mm,差异无统计学意义(F=1.187,P=0.319)。戴镜24mo后平均光学区偏中心距离为0.79±0.35mm,眼轴增长均值为0.32±0.30mm。戴镜24mo后平均偏中心距离轻度(<0.5mm)、中度(0.5～1.0mm)、重度(>1.0mm)的眼轴增长分别为0.45±0.34、0.32±0.28、0.23±0.29mm,差异有统计学意义(F=3.825,P=0.024)。戴镜后的平均偏中心距离和眼轴增长经线性回归分析,其线性关系有统计学意义(F=7.246,P=0.008),线性回归方程Y=0.478-0.194X。戴镜24mo后,18眼有重影,其偏中心距离均值1.18±0.36mm; 116眼无重影,其偏中心距离均值0.73±0.31mm,偏中心距离比较差异有统计学意义(t=5.59,P<0.01)。

结论：光学区偏中心距离在角膜塑形镜治疗3mo后趋于稳定,且对控制近视的效果和视觉质量有影响。     

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。     

低中度近视儿童中心凹脉络膜厚度相关因素分析

目的：探讨影响低中度近视儿童中心凹脉络膜厚度(SFCT)的相关因素。

方法：横断面研究。选择2020-10/12在徐州医科大学附属徐州市立医院眼科就诊的6～12岁近视儿童,按睫状肌麻痹验光所得等效球镜度(SER)纳入-0.75～-3.00D的低度近视患者60例60眼,-3.25～-6.00D的中度近视患者50例50眼,测量其SFCT、中心凹视网膜厚度(SFRT)、眼轴长度(AL)、眼调节参数,调查其年龄、性别、身高、体质量、父母近视情况,分析SFCT与各参数的关系。

结果：低、中度近视组SFCT分别为273.30±44.93、237.16±48.56μm(P<0.01),Pearson相关分析得出SFCT与SER、AL、身高均有相关性(r=0.35、-0.45、-0.19,均P<0.05),与其他因素均无相关性(均P>0.05),多重线性回归显示SFCT随着AL的增长而变薄(B=-19.87,P<0.01)。

结论：低中度近视儿童SFCT与SER、AL、身高均有关,其中AL是影响SFCT的最主要因素,与其他因素关系不明显。     

SMILE和FS-LASIK联合monovision治疗近视合并老视的疗效比较

目的：观察用monovision原理设计治疗近视合并老视在飞秒激光小切口基质透镜取出术(SMILE)和飞秒激光辅助原位角膜磨镶术(FS-LASIK)应用后的远视力、近视力。

方法：在我院行monovision设计进行近视激光治疗的近视合并老视患者,SMILE组10例20眼,年龄45±2.83岁,屈光度-5.42±1.74D; FS-LASIK组9例18眼,年龄45±1.97岁,屈光度-5.60±1.84D。组间及组内对比手术前后单眼及双眼远、近视力。

结果：术前SMILE组：主视眼：远视力0.05±0.04,近视力0.36±0.15; 客观眼：远视力0.35±0.11,近视力0.16±0.11; 双眼：远视力0.05±0.05,近视力0.18±0.09。术前FS-LASIK组：主视眼：远视力0.09±0.09,近视力0.42±0.17; 客观眼：远视力0.44±0.11,近视力0.19±0.10; 双眼：远视力0.03±0.04,近视力0.19±0.11。两组间术前各参数均无差异(P>0.05)。术后SMILE组：主视眼：远视力为-0.01±0.06,近视力为0.32±0.14; 客观眼：远视力0.16±0.18,近视力0.12±0.12; 双眼：远视力-0.04±0.07,近视力0.10±0.11。术后FS-LASIK组：主视眼：远视力0.03±0.03,近视力0.45±0.13; 客观眼：远视力0.20±0.15,近视力0.24±0.12; 双眼：远视力0.01±0.03,近视力0.22±0.09。术后两组双眼远视力、近视力均有差异(t=-2.383,P=0.034; t=-2.424,P=0.027)。SMILE组术后主视眼远视力(t=3.914,P=0.004),客观眼远视力(t=4.894,P=0.001),双眼远视力(t=4.870,P=0.001),双眼近视力(t=2.388,P=0.041)均优于术前预计视力。FS-LASIK组术后客观眼远视力优于术前(t=4.068,P=0.004)。

结论：对近视角膜屈光手术的患者,用monovision设计治疗老视,SMILE和FS-LASIK均能达到预计效果,但SMILE术后的双眼远、近视力更优。     

低浓度阿托品联合角膜塑形镜矫治近视的临床观察

目的：观察低浓度阿托品滴眼液联合角膜塑形镜治疗青少年低中度近视的有效性及安全性。

方法：选取2016-05/2018-08于我院就诊的青少年低中度近视患者126例126眼(均取右眼数据),使用夜戴型角膜塑形镜1mo后随机进行分组,试验组患者63眼每晚联合应用低浓度(0.01%)阿托品滴眼液1次,对照组患者63眼每晚联合应用聚乙二醇滴眼液1次。随访观察眼轴、等效球镜度、最佳矫正近视力、瞳孔直径、调节幅度、泪膜破裂时间、眼压的情况。

结果：联合治疗1a,试验组和对照组低度近视患者眼轴分别增长0.13±0.03、0.22±0.05mm,中度近视患者眼轴分别增长0.12±0.03、0.20±0.05mm; 低度近视患者等效球镜度分别增加0.16±0.07、0.21±0.08D,中度近视患者等效球镜度分别增加0.16±0.05、0.20±0.09D,两组之间眼轴和等效球镜度变化均有差异(均P<0.05)。治疗1a后,两组患者最佳矫正近视力、泪膜破裂时间、眼压均无差异(P>0.05),但试验组患者瞳孔直径较对照组明显增大,调节幅度较对照组降低(P<0.05)。

结论：0.01%阿托品滴眼液联合角膜塑形镜能更有效控制青少年近视进展,且安全有效。     

Corvis ST评估近视患者角膜生物力学参数及相关影响因素

目的：利用可视化角膜生物力学分析仪(Corvis ST)评估不同近视患者角膜生物力学参数的差异及其与眼部其他生物测量参数的相关性。

方法：选取2021-05/12就诊于武汉艾格眼科医院角膜屈光手术科的近视患者132例，均取右眼数据。根据等效球镜度数(SE)将受检者分为中低度近视(-0.50～-6.00D)，高度近视(>-6.00～<-8.00D)，超高度近视(≥-8.00D)。使用Corvis ST测量角膜生物力学形变基础参数包括：包括最大变形幅度(DA)、最大压陷反向曲率半径(HCR)、最大压陷峰距(PD)； 整合参数包括：第一次压平时角膜硬度参数(SP-A1)、综合半径(IR)、2mm处形变幅度的比值(DA ratio)、角膜厚度变异率(ARTh)、Corvis ST生物力学指数(CBI)； 测量眼部其他生物参数包括：SE、眼压(IOP)、眼轴长度(AL)、中央角膜厚度(CCT)、水平角膜直径(WTW)、视神经纤维层厚度(RNFL)。分别比较三组近视患者角膜生物力学参数的差异，并进一步分析三组近视患者角膜生物力学参数与眼部其他生物测量参数及年龄的相关性。

结果：中低度、高度、超高度近视组的SP-A1分别为106.8±16.2、115.6±21.9、106.9±11.5，高度近视组SP-A1高于中低度、超高近视组(均P<0.05)。所有角膜生物力学与CCT均有显著相关性(P<0.01)； 除ARTh外，其余角膜生物力学与IOP均有相关性(P<0.05)； AL与PD呈显著正相关(r=0.270，P=0.002)，与HCR呈较弱的正相关(r=0.177，P=0.043)，与IR呈较弱的负相关(r=-0.183，P=0.036)； WTW与PD、DA、DA ratio均呈正相关(r=0.363，P<0.001； r=0.252，P=0.003； r=0.200，P=0.02)； 角膜生物力学参数与年龄、SE、RNFL均无相关性。

结论：高度近视患者的角膜硬度高于中低度和超高度近视患者，IOP、CCT均为影响角膜生物力学的重要因素。部分生物力学参数和AL、WTW也有一定的相关性，随着眼轴的增长，角膜形变范围PD越大，HCR变大，IR变小，但后两者显著性不强； 角膜直径越大，角膜形变幅度越大。临床中需重视超高度近视患者角膜生物力学参数。     

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。     

青年近视人群屈光度与眼球生物学参数的相关性

目的:通过测量青年近视人群等效球镜度(SE)、眼轴(AL)、眼压(IOP)、中央角膜厚度(CCT)、前房深度(ACD)以及平均角膜曲率(Km),探讨屈光度与眼球生物学参数的关系。方法:回顾性分析2017-03/2019-07在兰州华厦眼科医院就诊的近视患者1619例1619眼的术前检查资料,根据SE将其分为低、中、高、超高度近视组。收集术前SE、AL、IOP、CCT、ACD、Km等眼球生物学参数,并分析其相关性。结果:低、中、高、超高度近视组SE分别为-2.38±0.49、-4.60±0.82、-7.40±1.08、-11.58±1.23D,AL分别为24.55±0.72、25.68±0.77、26.75±0.64、28.00±0.56mm,IOP分别为14.68±3.18、14.78±2.81、15.19±2.66、15.70±2.68mmHg,ACD分别为3.41±0.24、3.34±0.25、3.32±0.25、3.24±0.27mm,Km分别为42.96±1.22、43.02±1.43、43.29±1.47、43.56±1.47D,四组患者AL、IOP、ACD、Km均有明显差异(P<0.001),而CCT无明显差异(P>0.05)。SE值与AL、IOP、CCT、Km呈正相关性(r=0.851、0.104、0.066、0.157,均P<0.001),与ACD呈负相关性(r=-0.129,P<0.001)。结论:随着屈光度的增加,近视患者AL增长,Km增高,IOP增高,CCT增高,ACD变浅。     

Myopia control in Mendelian forms of myopia

Purpose

To study the effectiveness of high-dose atropine for reducing eye growth in Mendelian myopia in children and mice.

Methods

We studied the effect of high-dose atropine in children with progressive myopia with and without a monogenetic cause. Children were matched for age and axial length (AL) in their first year of treatment. We considered annual AL progression rate as the outcome and compared rates with percentile charts of an untreated general population. We treated C57BL/6J mice featuring the myopic phenotype of Donnai–Barrow syndrome by selective inactivation of Lrp2 knock out (KO) and control mice (CTRL) daily with 1% atropine in the left eye and saline in the right eye, from postnatal days 30–56. Ocular biometry was measured using spectral-domain optical coherence tomography. Retinal dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were measured using high-performance liquid chromatography.

Results

Children with a Mendelian form of myopia had average baseline spherical equivalent (SE) –7.6 ± 2.5D and AL 25.8 ± 0.3 mm; children with non-Mendelian myopia had average SE −7.3 ± 2.9 D and AL 25.6 ± 0.9 mm. During atropine treatment, the annual AL progression rate was 0.37 ± 0.08 and 0.39 ± 0.05 mm in the Mendelian myopes and non-Mendelian myopes, respectively. Compared with progression rates of untreated general population (0.47 mm/year), atropine reduced AL progression with 27% in Mendelian myopes and 23% in non-Mendelian myopes. Atropine significantly reduced AL growth in both KO and CTRL mice (male, KO: −40 ± 15; CTRL: −42 ± 10; female, KO: −53 ± 15; CTRL: −62 ± 3 μm). The DA and DOPAC levels 2 and 24 h after atropine treatment were slightly, albeit non-significantly, elevated.

Conclusions

High-dose atropine had the same effect on AL in high myopic children with and without a known monogenetic cause. In mice featuring a severe form of Mendelian myopia, atropine reduced AL progression. This suggests that atropine can reduce myopia progression even in the presence of a strong monogenic driver.     

减小后光学区直径角膜塑形镜矫治近视的临床观察

目的:探讨与常规后光学区直径(6mm-BOZD)相比,减小后光学区直径(5mm-BOZD)角膜塑形镜在青少年近视矫治过程中的有效性及安全性。方法:采用前瞻性随机对照试验。选取2016-04/2019-01就诊的青少年近视患者100例100眼(均取右眼数据),球镜度为-1.00～-5.00D,随机分为两组：试验组患者配戴5mm-BOZD角膜塑形镜,对照组患者配戴6mm-BOZD角膜塑形镜。比较两组患者治疗1a期间的眼轴长度(AL)、等效球镜度(SE)、相对周边屈光度(RPR)、最佳矫正视力(BCVA)、裸眼近视力(NVA)、应用Efron分级记录眼前节情况、角膜滞后量(CH)、角膜阻力因子(CRF)、角膜补偿眼压(IOPcc)、平均非侵入性泪膜破裂时间(NIKBUTav)及高阶像差(RMS_h)。结果:治疗1a后,试验组患者的AL增加0.05±0.05mm,对照组增加0.15±0.05mm(t=-8.949,P<0.001);试验组患者SE增加-0.18±0.27D,对照组增加-0.42±0.35D(t=3.609,P=0.001);两组患者在N30°、N20°...     

Myopia risk behaviour related to the COVID-19 lockdown in Europe: The generation R study

Purpose

To battle the spreading of the COVID-19 virus, nationwide lockdowns were implemented during 2020 and 2021. Reports from China revealed that their strict home confinements led to an increase in myopia incidence. The Netherlands implemented a more lenient lockdown, which allowed children to go outside. We evaluated the association between COVID-19 restrictions, myopia risk behaviour and myopia progression in Dutch teenagers.

Method

A total of 1101 participants (mean age 16.3 ± 3.65 yrs) completed questionnaires about their activities before, during and after lockdown (March–October 2020). We used a repeated-measures ANOVA to compare time use between these time periods. Ocular measurements were acquired before the COVID-19 pandemic when participants were 13 years old; only 242 participants had ocular measurements at 18 years of age at the time of this analysis. Linear regression analyses were used to evaluate the association between lifestyle factors and myopia progression.

Results

Children were on average 16.2 (1.03) years of age during lockdown. Total nearwork increased from 8.11 h/day to 11.79 h/day, and remained higher after lockdown at 9.46 h/day (p < 0.001). Non-educational nearwork increased by 2.22 h/day (+49%) during lockdown and was associated with faster axial length progression (B 0.002 mm/h/year; SE 0.001 p = 0.03). Before and during lockdown, the mean time spent outdoors was similar (1.78 h/day and 1.80 h/day, respectively). After lockdown, time spent outdoors decreased to 1.56 h/day (p < 0.001).

Conclusion

The Dutch lockdown significantly increased digitised nearwork in adolescents but did not affect outdoor exposure. The changes in time spent performing nearwork remained after the lockdown measures had ended. We expect that the COVID-19 pandemic may lead to an increase in myopia prevalence and progression in European children.     

2011年上海市闸北区和田路小学小学生屈光状态及相关因素分析

目的:了解上海市闸北区和田路小学小学生屈光状态,分析视力与各影响因素的关系。方法:选取上海市闸北区和田路小学2011年下学期全体在校学生为样本进行调查,总计465名,参与调查460名(调查率98.9%),其中数据资料齐全的有445名。所有调查对象均进行以下检查:裸眼视力(uncorrected visual acuity,UCVA)、年龄(age)、身高(height,H)、体重(weight,W)、身体质量指数(body mass index,BMI)、球镜屈光度(diopter of spherical,S)、柱镜屈光度(diopter of cylinder,C)、等值球镜(spherical equivalent,SE)、眼轴长度(axial length,AL)及角膜曲率(corneal curvature,K),并分析整体屈光状态及各相关因素对视力的影响。裸眼视力使用标准对数视力表测量,采用小数准确记录,再转化为LogMar视力进行统计。结果:调查对象平均年龄9.49±1.47岁,平均SE为-0.85±1.82D,平均UCVA为+0.09±0.28,近视眼率为40.9%,散光眼率达58.9%。随着年龄的增加,近视眼率逐步增加,近视屈光度也明显加深(P=0.000)。随年龄增加,UCVA、AL增加(P<0.01),SE值下降(P<0.01)。UCVA与Age,H,W,BMI及AL呈正相关,而与S,C及SE呈负相关(P<0.01)。结论:上海市闸北区和田路小学的小学生中,近视及散光发病率较高,儿童视力与眼轴及生长发育密切相关。     

0.005%阿托品滴眼液联合角膜塑形镜控制青少年低度近视的可行性和民族差异性

目的:观察0.005%阿托品滴眼液联合角膜塑形镜控制不同民族青少年低度近视的有效性、安全性及民族差异性。方法:选取2021-01/10就诊于我院的汉族、哈尼族低度近视患者246例246眼,其中试验组患者120例120眼采用0.005%阿托品滴眼液联合角膜塑形镜治疗;对照组患者126例126眼采用角膜塑形镜治疗。观察两组患者戴镜前、戴镜1 a的裸眼视力、等效球镜度(SE)、眼轴长度(AL)、眼压、泪膜破裂时间(BUT)、角膜曲率、角膜厚度,记录两组患者并发症发生情况。结果:戴镜1 a,试验组患者AL和SE变化量(0.16±0.35 mm、-0.39±0.47 D)低于对照组(0.22±0.89 mm、-0.48±0.54 D),裸眼视力(LogMAR)优于对照组(0.11±0.25 vs 0.14±0.19)(P<0.05),BUT、前房深度、角膜曲率及角膜厚度均有差异(P<0.05),但两组患者眼压无差异(P>0.05),且两组中汉族和哈尼族患者裸眼视力、AL及SE变化量比较均无差异(P>0.05)。随访期间,两组患者均未出现明显的局部及全身不良反应,两组患者眼...     

Pattern of myopia progression in Chinese medical students: a two-year follow-up study

Objective

To estimate myopia progression during a 2-year period in a cohort of medical students in mainland China.

Methods

A 2-year longitudinal study was performed among 2,053 Chinese medical students (mean age 18.27 years, 1,057 females and 996 males) with their refraction measured at the start and the end of this study by autorefraction in cycloplegia. Information about the students’ age, gender, home origin (urban or rural), and eye history was obtained through a questionnaire.

Results

The overall prevalence of myopia increased significantly from 78.5 % to 84.1 % (P?<?0.001, right eye) and the mean refractive error increased significantly from ?2.52?±?2.13 D to ?2.84?±?2.16 D (P?<?0.001, right eye) over the 2 years. The rural students had a significantly greater increase in prevalence of myopia and the refractive error towards myopia than the urban ones (P?<?0.01 and 0.001 respectively). Females had a significantly faster myopic shift than males (P?<?0.001). Participants with myopia initially showed the fastest myopic shift among the initial refractive groups. The relationship between the initial refractive error and the myopic shift remained significant after adjusting for sex and home origin (P?<?0.05).

Conclusions

Myopia progressed as increase in prevalence of myopia and change in refraction towards myopia in this study population. Participants who were more myopic at baseline were more likely to have myopia progression. Female and rural participants had a faster myopic shift compared to male and urban ones, respectively.     

The scleral rigidity of eyes with different refractions

Background

The weakened biomechanical properties of the sclera is an important feature of myopic eyes. The quantitative evaluation in vivo of posterior scleral resistance to the elongation remains a challenge.

Methods

This study comprised 172 eyes from 86 subjects with a mean age of 20.6?years (range, 18–28?years). Ultrasound biometry was performed using an immersion technique and the A-scan device (the Biometer AL-1000 -TOMEY). The axial length of the eye was measured twice: before and during the application of an external pressure of 30?g on the eye. The difference between two mean values of AL measurements before and during the pressure application was considered as a degree of change in the axial length that resulted from the IOP elevation. The data were entered into an Excel spreadsheet (Microsoft Corp.) for subsequent analysis. Statistical analysis was performed using SigmaPlot software (version 11.0, Systat Software, Inc.). A value of 0.05 or less was considered statistically significant.

Results

The means ± SD of axial changes before and during the external pressure for hyperopia, emmetropia, myopia 0.5–3.0 D, myopia 3.25–6.0 D, myopia 6.25–12.0 D and myopia over 12.0 D were as follows: 0.03?±?0.01?mm, 0.05?±?0.01?mm, 0.18?±?0.07?mm, 0.31?±?0.02?mm, 0.38 ±?0.07?mm, and 0.51?±?0.9?mm, respectively. The difference among groups was statistically significant.

Conclusions

In conclusion, our study indicates that the biomechanical properties of the scleral coat, in terms of stretching and AL elongation, are measurable. The hypermetropic and emmetropic eyes possessed stiff sclera. The extent of AL remained practically unchanged during IOP elevation in these eyes. The absolute majority of the myopic eyes revealed a biomechanical weakness of the scleral shell. A higher degree of myopia was associated with increased AL elongation. Our approach to measuring the biomechanical properties of the sclera may have clinical significance in the future.