不同类型高度病理性屈光参差屈光要素分析

目的分析不同类型高度病理性屈光参差同例双眼的屈光要素构成差异,探索影响屈光状态的主要因素、相互关系。方法收集136例等效球镜>3.00D的单纯近视性、远视性屈光参差,复性近视性、远视性屈光参差患者的临床资料,按屈光度数不同分为高屈光眼组和低屈光眼组;按屈光状态不同分为近视性屈光参差组(104例)和远视性屈光参差组(32例)。对所有患者双眼进行角膜地形图检查角膜屈光力,眼部A超检查前房深度、晶状体厚度及眼轴长度,对相关数据进行配对t检验,对各屈光要素与眼球屈光度进行多元线性回归分析。结果角膜屈光力近视性屈光参差组双眼相似率为79.81%,高于远视性屈光参差组的68.75%(P<0.05);前房深度近视性屈光参差组双眼相似率为68.27%,远视性屈光参差组为59.38%,二者差异无统计学意义(P>0.05);晶状体厚度近性视屈光参差组双眼相似率为79.81%,远视性屈光参差组为90.63%,二者差异无统计学意义(P>0.05);眼轴长度近视性屈光参差组双眼相似率为12.50%,远视性屈光参差组为18.75%,相似率均较低(P>0.05)。多元线性回归分析示:近视性屈光参差屈光度数与角膜屈光力、晶状体厚度及眼轴长度呈正相关关系(b=0.836、1.406、2.279,均为P<0.05),与前房深度呈负相关关系(b=-2.051,P<0.05);远视性屈光参差屈光度数与角膜屈光力、晶状体厚度及眼轴长度成负相关关系(b=-0.912、-1.389、-2.318,均为P<0.05),与前房深度无显著相关关系(P>0.05)。结论角膜屈光力及眼轴长度是影响眼球屈光状态的主要因素。前房深度及晶状体厚度在眼纵轴线上的位置对眼球屈光状态的影响不容忽视。     

Myopia in adults with retinopathy of prematurity

PURPOSE: To evaluate myopia in adults with retinopathy of prematurity (ROP). DESIGN: Observational case series. METHODS: Axial length (AL), corneal radius (CR), and AL/CR ratio were measured in myopic adults with ROP using ultrasound A-scan biometry and keratometry, respectively. RESULTS: Twenty-five eyes of 18 patients (mean age, 48 years) were studied. Mean gestational age at birth was 29 weeks. The average refraction was -5.23 diopters, AL 24.43 mm, CR 7.45 mm, and AL/CR ratio 3.28. On average, myopic adults with ROP had a shorter AL and decreased CR (increased corneal curvature), but a similar AL/CR ratio, relative to adults with the same degree of myopia who were born full-term. Myopic adults with ROP also had increased lens thickness (LT) and shallow anterior chamber depth (ACD). CONCLUSIONS: Myopic adults with ROP had a shorter AL and smaller CR than expected for their degree of myopia. However, AL/CR ratios for these patients were similar to the values of adults who were born full-term. These results suggest that the refractive element most responsible for myopia in adults with ROP is higher corneal curvature (decreased CR), whereas the predominant factor in adult myopic individuals who were born full-term is increased AL. We believe that increased LT and shallow ACD make a lesser contribution to myopia in adults with ROP.     

近视眼眼轴长度、前房深度及晶状体厚度的测量分析

目的探讨近视屈光度与眼袖长度、前房深度及晶状体厚度之间的关系。方法采用日本产NIDEK-US2520B型超声显像仪对屈光度在-3.00D以上的近视患者163例(312眼)进行眼轴长度、晶状体厚度和前房深度测量。结果随着近视度数的增加,其眼轴长度和前房深度明显增加,而晶状体厚度与眼轴长度的比值则显著降低(P<0.05)。在屈光度相同的各组中,眼轴长度、晶状体厚度和晶状体厚度与眼轴长度比值存在明显的性别差异(P<0.05),而前房深度的性别差异无显著性(P>0.05)。结论近视屈光度的增加可同时伴有眼轴长度、前房深度和晶状体厚度与眼轴长度比值的改变。     

A comparison of laser photocoagulation with cryotherapy for threshold retinopathy of prematurity at 10 years: part 2. Refractive outcome

OBJECTIVE: To compare the refractive outcome of eyes treated with cryotherapy for threshold retinopathy of prematurity (ROP) with eyes treated with laser photocoagulation. DESIGN: Extended follow-up of a randomized controlled clinical trial. PARTICIPANTS: One hundred eighteen eyes from 66 patients were randomly assigned to receive either cryotherapy or laser photocoagulation for threshold ROP. Twenty-five patients (44 eyes treated) were available for follow-up examination 10 years later. INTERVENTION: Cycloplegic autorefraction or retinoscopy was performed. Immersion ultrasound biometry (A-scan) was also performed, and an autokeratometer was used for keratometry. If an A-scan could not be tolerated or the patient was not cooperative, a B-scan through-the-lid biometry was performed. Corneal thickness was measured using optical coherence tomography. MAIN AND SECONDARY OUTCOME MEASURES: Refractive error. In addition, anterior chamber depth, lens thickness, and axial length were measured. Central corneal thickness measurements and keratometric readings were also obtained. RESULT: Eyes treated with cryotherapy were significantly more myopic than those treated with laser photocoagulation. When comparing patients with bilateral treatment, the mean spherical equivalent (SE) of eyes treated with laser was -4.48 diopters (D) compared with a mean SE of -7.65 D for eyes treated with cryotherapy (n = 15 pairs of eyes, P = 0.019). Cryotherapy-treated eyes had a mean axial length of 21.7 mm versus 22.9 mm for laser-treated eyes (P = 0.024, n = 12 pairs of eyes). The anterior chamber depth and lens thickness averaged 2.86 mm and 4.33 mm, respectively, in the cryotherapy-treated eyes compared with 3.42 mm and 3.95 mm in the laser-treated eyes (P < 0.001, n = 12 pairs for both measurements). There were no statistical differences in anterior corneal curvature and central corneal thickness between the two treatment modalities. Crystalline lens power bore the strongest correlation to refractive outcomes in both laser-treated (r = 0.885, P < 0.001) and cryotherapy-treated eyes (r = 0.591, P = 0.026). Although keratometric readings were higher than normal values in these eyes, there was no correlation to the degree of myopia. CONCLUSIONS: Laser-treated eyes were significantly less myopic than cyrotherapy-treated eyes. Lens power seemed to be the predominant factor contributing to the excess myopia.     

Long-term refractive and biometric outcomes following diode laser therapy for retinopathy of prematurity.

PURPOSE: To assess the long-term refractive and biometric outcomes of diode laser-treated eyes in threshold retinopathy of prematurity (ROP). METHODS: Cycloplegic autorefraction and biometry (Zeiss IOLMaster) were performed, at a mean follow-up of 11 years, on 16 laser-treated eyes with threshold ROP and 9 comparison eyes with subthreshold untreated ROP. RESULTS: The laser-treated eyes had a mean spherical equivalent of -2.33 D with a mean astigmatic error of 1.38 D. The comparison eyes had a mean spherical equivalent of +1.07 D with a mean astigmatic error of 0.42 D. This trend toward increased myopia in treated eyes did not achieve statistical significance (p=0.08). The myopia in the laser group appeared to be slowly progressive in nature when compared with earlier refractive data for these patients. The laser-treated eyes had reduced anterior chamber depth (ACD) compared with the subthreshold eyes (p=0.02). When physiologic accommodation was inhibited by cycloplegic drops, the anterior chamber deepened by 0.13 mm in the laser-treated eyes and by 0.06 mm in the comparison eyes. This effect of accommodation on ACD did not differ significantly between the two groups (p=0.23). The laser-treated eyes and the comparison eyes did not differ significantly in terms of axial length, corneal power, corneal diameter, or lens power. However, both groups had steeper corneas, shallower anterior chambers, and shorter axial lengths when compared with historical full-term controls. CONCLUSIONS: Myopia in premature infants requiring laser treatment for ROP is associated with a shallowing of the anterior chamber and a steepening of the cornea. Physiological accommodation is not impaired by laser therapy or by severe ROP.     

高度近视白内障患者手术前后眼生物测量参数相关性分析

目的：对高度近视白内障患者手术前后眼生物测量参数进行分析,为高度近视白内障的人工晶状体屈光度计算公式提供参考。

方法：选取2011-01/2017-05我院收治的152眼高度近视白内障患者,所有患眼眼轴≥26mm,测量白内障手术前眼轴长度、角膜曲率、前房深度、晶状体厚度,以及手术后3mo角膜曲率、前房深度。分析各参数之间相互关系,并对术后前房深度进行多元线性回归分析。

结果：术前眼轴长度与术前角膜曲率、晶状体厚度呈正相关(r=0.236、0.216,P<0.05)。术前眼轴长度与术前前房深度无相关关系(P>0.05)。术前前房深度与术前角膜曲率无相关关系(P>0.05)。术前前房深度与术前晶状体厚度呈负相关关系(r=-0.513,P<0.05)。术后前房深度与术前眼轴长度、术前前房深度、术前角膜曲率、术后角膜曲率呈正相关关系(r=0.374、0.364、0.333、0.356,P<0.05)。术后前房深度与术前晶状体厚度无相关关系(P>0.05)。术后前房深度的多元线性回归方程为：术后前房深度=-2.592+0.091×术前眼轴长度+0.078×术前角膜曲率+0.491×术前前房深度。

结论：通过测量术前眼轴长度、角膜曲率、前房深度,利用术后前房深度多元回归方程,可以计算出术后前房深度,从而为高度近视白内障患者术后人工晶状体屈光度计算公式提供参考。     

高度近视的屈光度影响因素多元线性回归分析

目的 分析高度近视眼屈光度的相关影响因素,明确高度近视眼患者的眼轴长度、角膜曲率、前房深度等因素与屈光度的关系.方法 对42例(77只眼)屈光度>-7.0D的高度近视眼患者进行研究,以前房深度、晶状体厚度、玻璃体腔深度、角膜曲率(K1/K2)、眼轴长度、角膜厚度,眼压为自变量,以等效球镜SE作为因变量,用多元线性同归模型筛选出有影响的因素,并比较各因素影响力的大小.采用SPSS 13.0统计软件进行多元线性逐步回归分析.结果 经相关分析,得到线性回归方程为:等效球镜(屈光度)=-39.558+1.141×眼轴长度+0.560×角膜曲率K2-1.515×前房深度-0.089×眼压.回归效果检验F=60.114(P<0.01).结论 眼轴长度、角膜曲率K2、前房深度,眼压对高度近视眼屈光度有明显影响,其中眼轴长度对高度近视眼屈光度影响显著.     

高度近视眼透明晶状体置换手术后眼前节结构变化的临床观察

目的:通过超声生物显微镜观察高度近视眼透明晶状体置换手术后眼前节结构的变化。方法:对20例36眼以矫正高度近视为目的高度近视患者,行透明晶状体超声乳化吸除联合折叠式人工晶状体植入手术。术前和术后1mo分别应用超声生物显微镜(ultrasound biomicroscopy,UBM)测量前房深度(anterior chamber depth,ACD)、前房角开放距离(angle opening distance,AOD)和前房角开放度数(anterior angle,AA)。结果:患者术后1mo的ACD,AOD,AA与术前相比有显著性差异(P=0.000),术后房角宽度、前房深度明显大于术前;眼轴与术后、术前前房深度的差值呈负相关(r=-0.711,P=0.000)。结论:高度近视患者行超声乳化透明晶状体吸除联合折叠式人工晶状体植入术,术后前房加深,房角增宽,眼轴与术后、术前前房深度的差值呈负相关。     

Changes of axial length and keratometry after keratoplasty for keratoconus using the guided trephine system

PURPOSE: The purpose of this study was to examine the cause of increasing myopia after penetrating keratoplasty for keratoconus with the guided trephine system. DESIGN: Prospective interventional study cohort. METHODS: Thirty eyes (28 patients) after keratoplasty for keratoconus were examined. Preoperatively and 1, 3, 6, 12, and 24 months postoperatively subjective refraction was evaluated. Keratometry was calculated with a computerized videokeratoscope (TMS-1). Axial length was measured using applanation ultrasonography before surgery and 2 years after surgery. Anterior chamber depth, lens thickness, and vitreous length were taken into consideration. RESULTS: The mean spherical equivalent was + 2.22 +/- 3.47 diopters 1 month postoperatively and had a continuous myopic shift to -1.02 +/- 2.65 diopters 2 years postoperatively. This was associated with a significant increase in mean keratometric levels from + 41.72 +/- 2.96 diopters 1 month postoperatively to + 43.77 +/- 2.29 diopters 2 years postoperatively (r(s) = -0.36, P =.05). Overall, no significant changes in axial length were observed. However, vitreous length showed a small but statistically significant increase. As expected, mean anterior chamber depth decreased significantly postoperatively (P 相似文献   

先天性白内障近视发生的危险因素分析

目的：探讨先天性白内障近视发生的危险因素,提供预防近视的科学依据。方法：对83例109只先天性白内障眼球的各屈光因子进行生物学测量,确定其屈光状态,并用Logistic回归的方法进行单因素和多因素分析。结果：先天性白内障的近视发和生率是61.27%,眼轴长度为近视发生的主要危险因素,OR＝138.699。结论：尽早去除先天性白内障所造成的形觉剥夺,保持或恢复视觉发育敏感期正常的视觉环境,有利于预防近视的发生。     

Long‐term biometric optic components of diode laser‐treated threshold retinopathy of prematurity at 9 years of age

Purpose: To assess quantitatively the biometric optic components and its relationship with refractive status in preterm school children with diode laser‐treated threshold retinopathy of prematurity (ROP). Methods: A prospective, cross‐sectional study in which ultrasound biometric measurement of optic components and cycloplegic refraction were performed on 24 consecutive preterm children with diode laser‐treated threshold ROP at the age of 9 years. The study results were compared with 1021 age‐matched full‐term control children from a national survey. Results: The eyes with laser‐treated ROP showed statistically significantly thicker lens (3.94 versus 3.39 mm), steeper vertical corneal curvature (7.47 versus 7.67 mm) and shallower anterior chamber depth (ACD) (2.91 versus 3.58 mm) than age‐matched full‐term controls, but no difference in axial length (23.32 versus 23.24 mm). The laser‐treated eyes had a mean spherical equivalent (SE) of ?4.49 D compared with mean SE of ?0.44 D in controls. Of 46 eyes studied, 93% of eyes were myopic and 28.3% with high myopia (<?6.0 D) compared with the 32% prevalence of myopia in controls. In preterm children, younger gestational age tended to correlate with shallower ACD (r = 0.352) and thicker lens (r = ?0.298); lower birth weight tended to correlate with shallower ACD (r = 0.372) and steeper cornea (r = 0.360). Conclusions: There were higher prevalence and greater magnitude of myopia in preterm children. The significantly thicker lens, steeper corneal curvature and shallower anterior chamber depth are the major factors contributing to the development of myopia in preterm school children with laser‐treated threshold ROP.     

Long term refractive outcome in eyes of preterm infants with and without retinopathy of prematurity: comparison of keratometric value, axial length, anterior chamber depth, and lens thickness

BACKGROUND/AIMS: A longitudinal study of premature infants was conducted to examine changes in refractive status and their relation with age and factors influencing the occurrence and degree of myopia. Identification of which of the various refractive factors play important parts in relation to myopia in premature infants was attempted. METHODS: Under observation were 125 eyes in 65 patients who were found to demonstrate no signs of retinopathy of prematurity (ROP) or who had grade I or II ROP without or after cryotherapy. Cycloplegic refractions were conducted at 6 months, 3 years, and 6 years of age; at 6 years of age keratometric values, lens thicknesses, and axial lengths were recorded, and anterior chamber depths also were measured. RESULTS: Myopia begins to appear at 6 months of age and its severity increases between the ages of 6 months and 3 years. The condition showed no further progress in subjects older than 3 years. Of the 104 eyes with ROP, those eyes with cicatricial retinopathy tended towards myopia and high myopia while there was no difference in the degree of myopia related to whether or not cryotherapy was conducted. At 6 years of age, the premature infants exhibited shallower anterior chambers, thicker lenses, and higher axial lengths when the degree of the myopia was higher. The keratometric values, however, appeared to bear no relation to the degree of the myopia. CONCLUSION: These results suggest that the occurrence of myopia is related more strongly to whether or not there is cicatricial retinopathy than whether or not there is cryotherapy. Also, the degree of the myopia was found to be related to the depth of the anterior chamber, the thickness of the lens, and the change in axial length but not to keratometric value.     

Changes of axial dimensions of the eye during growth in emmetropia, myopia and hyperopia

PURPOSE: The aim ot this study was to evaluate changes ot axial dimensions ot the eye during growth in emmetropia, myopia and hyperopia. MATERIAL AND METHODS: We examined 183 children (363 eyes) aged 4 to 19 with emmetropia, myopia and hyperopia. All measurements were performed after cycloplegia with 1% tropicamidum (Polfa Warszawa). Total and corneal refraction was examined with autokeratorefractometer (Nikon NRK-8000). Then we used ultrasound biometer Ocuscan (Alcon, USA), to measure axial length of the eye, axial length of the vitreous cavity, axial dimension of the lens and axial depth of the anterior chamber. RESULTS AND CONCLUSIONS: 1. Growth of the axial length of the emmetropic eyes is finished at the age of 12, in hyperopic eyes in the age of 11 and in myopic eyes growth is proportional until the age of 14 and then significantly accelerates. 2. Growth of the axial length is mainly caused by increasing axial length of vitreous cavity. A little role in human eye growth is also played by increasing depth of the anterior chamber. 3. Between 4 and 19 years old, mean cycloplegic axial dimension of the lens is slightly decreasing in emmetropic and hyperopic eyes, whereas in myopic eyes is constant.     

角膜塑型术后眼轴的超声生物测定分析

目的：探讨角膜塑型术后眼的前房深度(ACD)、晶状体厚度(LT)、眼轴长度(AL)的变化。

方法：对进行角膜塑型镜治疗的120例120眼进行了前瞻性临床研究,将角膜塑形术术前及术后1a的超声检查结果进行比较。

结果：角膜塑型镜治疗1a后,LT较治疗前增厚,其中低度近视组增厚0.14mm,差异有显著的统计学意义(P<0.01)。中高度近视组增厚0.05mm,差异有统计学意义(P<0.05)。前房深度﹑眼轴长度的差异没有统计学意义(P>0.05)。

结论：角膜塑型术后,存在着晶状体屈光力的改变。调节因素可能参与着角膜塑型镜延缓近视发展的机制。     

屈光参差眼的屈光结构分析

目的 探讨屈光参差眼屈光要素的差异程度对屈光参差的形成作用.方法 收集双眼等效球镜度数差＞2.00 D的屈光参差患者91例,按屈光参差类型分为远视性屈光参差和近视性屈光参差2组.用日本Topcon KR.8800自动验光仪测量双眼屈光度数和角膜曲率（CC）.用法国Quantel 0459 A型超声生物测量仪测量双眼前房深度（ACD）、晶状体厚度（LT）、玻璃体腔长度（VCL）及眼轴长度（AL）,将患者的双眼进行自身对照观察,所测数据采用配对t检验进行统计学分析.屈光参差眼各屈光要素与年龄及分组的关系采用多元线性回归进行分析,屈光参差眼的屈光要素与眼轴的关系采用偏相关的方法进行分析.结果 屈光参差者双眼之间只有玻璃体腔长度和眼轴长度存在差异（tVCL=9.506、3.654,P均＜0.01 tAL=12.334、3.447,P均＜0.01）.多元线性回归分析发现：屈光参差者双眼的角膜曲率、前房深度都与年龄无关 近视性屈光参差眼的角膜曲率、前房深度都大于远视性屈光参差眼（tK=4.600,P＜0.01 tACD=2.894,P＜0.01）,而晶状体厚度没有差异 2组屈光参差者双眼的角膜曲率、前房深度都与眼轴长度无关,而晶状体厚度与眼轴相关（r=0.358、0.296,P＜0.01）.玻璃体腔的长度与眼屈光状态和眼轴都相关（r=0.975、0.979,P＜0.01）.结论 玻璃体腔长度的变化是屈光参差发生的内在根本原因.     

Correlation analysis and multiple regression formulas of refractive errors and ocular components

The multiple regression formulas and correlation of ocular components with refractive errors are presented by Gaussian optics. The refractive error changing rate for the cornea and lens power, the axial length, anterior chamber depth (ACD) and vitreous chamber depth (VCD) are calculated, including nonlinear terms for more accurate rate functions than the linear theory. Our theory, consistent with the empirical data, shows that the Pearson correlation coefficients for spherical equivalent (SE) and ocular components are highest for SE with axial length, ACD and VCD and weakest for corneal power, lens power and lens thickness. Moreover, our regression formulas show the asymmetric feature of the correlation that the axial length, ACD and VCD are more strongly correlated (with higher negative regression constants) with refractive errors in eyes with hyperopia than in eyes with myopia, particularly for severe hyperopia.     

角膜原位磨镶术中负压吸引对眼球结构影响的分析

目的 研究角膜原位磨镶术中负压吸引对眼球结构改变的影响.方法 对64例(105只眼)行角膜原位磨镶术的近视眼患者分别在Hansatome角膜板层刀负压吸引眼球前以及吸引过程中用A型超声测量仪进行前房深度,晶状体厚度,玻璃体腔长度以及眼球长度测量,比较负压吸引前及吸引过程中上述指标的改变,探讨其意义.结果 患者年龄最大37岁,最小18岁,平均22.4岁,等值球镜度(-4.50±1.75)D,负压吸引前超声测量前房深度,晶状体厚度,玻璃体腔长度,眼轴长度分别为(3.62±0.29)mm,(3.68±0.34)mm,(17.79±1.01)mm,(25.09±0.99)mm;负压吸引中上述指标分别为(3.76±0.26)mm,(3.52±0.26)mm,(17.95±1.01)mm,(25.23±1.01)mm.负压吸引后前房深度,玻璃体腔长度和眼轴长度分别增加0.14mm,0.16mm和0.14mm,差异有统计学意义(P＜0.01);晶状体厚度减少0.15mm,差异有统计学意义(P＜0.01).结论 LASIK手术中负压吸引可引起眼球结构改变,导致前房深度,玻璃体腔长度以及眼轴长度增加,晶状体厚度减少,手术中应尽量减少负压吸引时间,降低负压对眼球的影响.     

Ocular dimensions following cryotherapy for active stage of retinopathy of prematurity

In a group of 21 premature children in which 4 to 10 years earlier 26 eyes with stage 4 of active retinopathy of prematurity (ROP) were treated by cryopexy on the avascular retina, and 15 fellow eyes with stage 2 of active ROP were not treated, comparative measurements of the central corneal thickness, anterior chamber depth and eye axial length were performed. Not significant statistical differences of these parameters were found between the cryotreated and untreated eyes. The axial length was correlated with the degree of myopia.     

Optical constants and dimensions for the myopic, hyperopic and normal rhesus eye

Complete optical constants and physical dimensions are presented for eight ametropic rhesus eyes in the range from -11.00 diopters of myopia to +8.00 diopters of hyperopia and compared with the same measurements from 40 essentially emmetropic normal control eyes. The optical constants are calculated from a Gullstrand analysis modified for the rhesus eye, and include focal lengths, cardinal points, lens power and total optical power. The physical dimensions, from keratometry and ultrasound, include corneal radius, anterior chamber depth, lens thickness, vitreous depth and axial length. A regression analysis of the data shows that refraction is strongly correlated with both axial length and vitreous depth (at the rate of 3.7 and 4.2 diopters mm-1, respectively; correlation coefficients of -0.962 and -0.821) but is essentially independent of lens power, corneal power, and total optical power. These results allow us to infer that experimentally induced ametropia in the rhesus is caused by a distortion of the globe, and is not caused by the cornea or the lens.     

Component dependent risk factors for ocular parameters in Singapore Chinese children

OBJECTIVE: To examine the risk factors for variations in ocular biometry parameters in Singapore Chinese children, a population with a known high prevalence rate of myopia at an early age. DESIGN: Cross-sectional study. PARTICIPANTS: Children aged 7 to 9 years (n = 1453) from three schools in Singapore. METHODS: The children underwent A scan biometry and cycloplegic autorefraction measurements. Questions were asked regarding number of books read per week, night lighting, and parental myopia. MAIN OUTCOME MEASURES: Axial length, vitreous chamber depth, lens thickness, anterior chamber depth, refraction, and corneal curvature radius measurements were made. RESULTS: After controlling for several factors, the axial lengths were found to be longer and vitreous chambers deeper in children who were older, male, read more than two books per week, or taller, and those who had at least one parent who was myopic. In these models, children who read more than two books per week had axial lengths that were 0.17 mm longer and vitreous chambers that were 0.15 mm deeper compared with children who read two or fewer books per week. Anterior chambers were deeper in males and taller children, whereas corneal curvature was steeper in female, older, and shorter children. CONCLUSIONS: Increases of axial length and vitreous cavity depth were associated with older age, being male, reading more than two books per week, increased height, and parental history of myopia. Of these risk factors, however, neither reading nor parental myopia history were associated with values for anterior chamber depth, corneal curvature, or lens thickness. These findings confirm that conventional risk factors for myopia associated with the vitreous cavity, but suggest that anterior segment parameters such as corneal curvature and lens thickness may be subject to unrelated postnatal growth control mechanisms.