Ocular development in children with unilateral congenital cataract and persistent fetal vasculature

INTRODUCTION

Normal ocular growth is vital for the development of the visual system in infants and young children

. The ocular development could be affected by various congenital factors

. Congenital cataract (CC) is one of the leading causes of childhood blindness

, and persistent fetal vasculature (PFV)is one of the most common ocular abnormalities that combined with unilateral CC, including three types: anterior, posterior and combined, with 90%

being in unilateral cases and its incidence rate up to 45%

. The form deprivation caused by CC that occurs in the critical period of visual development may lead to excessive ocular elongation

. While the hyaloid stalk from optic disc to the posterior capsule due to the failure of the embryonic hyaloid vasculature regression, namely PFV,could restrict ocular growth

. However, the ocular growth of unilateral patients who have both CC and PFV remains unclear,and these patients still exhibit poor visual outcomes

.Researchers and ophthalmologists have directed extensive efforts toward understanding the ocular development of patients with both unilateral CC and PFV. However, due to the limited number of cases with this complex ocular condition,previous reports regarding ocular development included both unilateral and bilateral patients with CC or without CC and manifested as different types of PFV, some of which did not have a hyaloid stalk, or lens opacity that affected the ocular growth

.

The current study aimed to investigate the ocular development of unilateral patients with both CC and PFV (focusing on only one type of PFV that has hyaloid stalk from the optic disc attached to the posterior capsular of the lens without retinal disorders) at different visual development stages (before and after 24mo) by analysing their ocular biometric parameters,including axial length (AL), keratometry, anterior chamber depth (ACD), lens thickness (LT), and vitreous length.This study could provide a deeper understanding of ocular development in patients with both CC and PFV, which is significant for the further treatment strategy and visual function improvement.

式中:Gk為最大迭代次數;ωint為初始慣性權重,ωint取0.9;ωend為最終的慣性權重,ωend取0.3。

在配電網中，由于受到變電站選址和通道受限的影響，往往需要對已有變電站進行升級改造，以滿足長期負荷增長需求；但由于現場施工條件限制和電網安全規程要求，不得不選擇全站停電改造，且改造周期較長。以某地市公司110 kV變電站為例，停電時間長達5個月，在此改造期間，配電網運行壓力巨大，能否平穩度過負荷高峰時期，缺乏理論支撐和可行性論證，施工中能否安排全站停電進行升級改造缺乏有效規程參考和指導意見。

SUBJECTS AND METHODS

隨著經濟的發展和社會的進步，人們的生活水平不斷地提高，人類平均壽命普遍延長，老年人口所占的比例越來越大，老年患者數量顯著增加[1]，面對日益增加的老年人口醫療需求，不僅要提升老年醫學臨床醫師的診療水平及臨床研究，同時需要完善醫學生培養模式以培養出時代所需的應用型人才。

Comparisons of Ocular Biometric Parameters Between Eyes with Congenital Cataract and Persistent Fetal Vasculature and those with Congenital Cataract Ⅰn the comparison of the affected eyes between group 1 and group 3, no difference was found regarding ALs, keratometries and ACDs (

=0.193,

=0.680, and

=0.137). Ⅰn the comparison of the affected eyes between group 2 and group 4, no difference was found regarding ALs, and ACDs (

=0.295 and

=0.446).However, the keratometries of the affected eyes in group 2 were steeper than those in group 4 (44.78±1.66

43.76±1.91 D,

=0.046; Table 2).

臨朐縣人大常委會高度重視代表述職工作，將縣鎮人大代表向原選區選民述職工作列為今年代表工作的重要內容，組織各鎮（街、園、區）以選區為單位，在全縣開展縣鎮人大代表述職評議活動，密切了代表與選民的聯系，激發了代表履職熱情，受到代表和人民群眾的一致好評。

The keratometries of the affected eyes were found steeper than those of the fellow eyes in patients older than 24mo, while no difference was found between the two eyes in patients younger than 24mo. Asbell

evaluated 11 eyes with PFV and found that the affected eyes had steeper corneas than those of the fellow eyes at any given age. Khokhar

also obtained similar outcomes by evaluating 21 cases with PFV.However, these studies included both PFV patients with or without CC, which may explain the difference in results. Ⅰn the current study, we only focused on patients with CC and PFV,with impairments of both anterior and posterior segments, and compared with patients with isolated CC. Among patients with CC and PFV, compared with the affected eyes in those younger than 24mo, those older than 24mo had steeper keratometries,which might be due to the ocular development of the older patients being affected by the disease for a longer period.Furthermore, no difference of the keratometries in the affected eyes was found between the age-matched patients with CC and PFV and those with isolated CC at a younger age (<24mo);however, the keratometries of the affected eyes were steeper in patients with CC and PFV at age of older than 24mo,indicating that the PFV might have additional influences on ocular development over time.

Ethical Approval The study was approved by the Human Research Ethics Committee of the Zhongshan Οphthalmic Center (ZΟC) at Sun Yat-sen University and conformed to the tenets of the Declaration of Helsinki. Ⅰnformed written consent was obtained from at least one parent of each patient.

Βecause ALs increase mostly during the first two years

,patients were separated into four groups: group 1 (patients with CC and PFV, <24mo), group 2 (patients with CC and PFV, ≥24mo), group 3 (patients with CC, <24mo) and group 4(patients with CC, ≥24mo).

Ocular Examinations All patients underwent comprehensive bilateral ocular examinations. Βest corrected visual acuity(ΒCVA, Teller acuity card test, Snellen tests, or Symbols tests according to ages) and intraocular pressure (Ⅰcare; TAΟ1i,Ⅰcare Finland Οy, Tonopen; Reicher Ⅰnc., Seefeld, Germany or non-contact tonometer; Nidek NT-530, Japan depending on age) were assessed. Visual acuity measurements were converted to logMAR units

. Slit-lamp examinations (ΒX900;HAAG-STREⅠT AG, Βern, Switzerland) were performed through dilated pupils. ALs were obtained by the contact A-scan (Β-SCAN-Vplus/ ΒⅠΟVⅠSⅠΟN, Quantel Medical,France), and ACDs and LTs were obtained in the same way.The vitreous length was calculated as the AL minus the sum of ACD and the LT. Keratometries were measured by the handheld keratometer (HandyRef-K, Nidek Co., Ltd., Japan)and the average keratometry power was calculated as the mean of the flat keratometry and the steep keratometry readings. A Β-mode ultrasound scan was performed in all eyes to evaluate the vitreous and retinal conditions. Patients who could not cooperate with the examinations were sedated by chloral hydrate (0.8 mL/kg, oral or rectal administration)

.

Statistical Analysis Statistical analysis was performed using SPSS (SPSS ver. 19.0, Chicago, ⅠL, USA). The patients’ ages,ALs, keratometries, ACDs, LTs, and vitreous lengths wereevaluated. The normality of data distribution was assessed with the Shapiro-Wilk test. ALs, keratometries, ACDs, LTs and vitreous lengths of the affected eyes and fellow eyes within the patients with CC and PFV were compared using paired

tests(or Wilcoxon signed rank test when the distribution was non-Gaussian), and those of the affected eyes between the patients with CC and PFV and the patients with CC were compared using independent-samples

test (or Wilcoxon Mann-Whitney when the distribution was non-Gaussian). All the statistical tests were two-tailed and a

value below 0.05 was considered statistically significant.

1）嚴格執行入河排污口設置申批程序。取締非法入河排污口，對不達標或未經處理的廢污水嚴禁入河，控制各水域的排污總量不得超過其水功能區的限制排污總量。……