Surgical interventions for bilateral congenital cataract

 

Abstract

Background

Congenital cataracts are opacities of the lens in one or both eyes of children that cause a reduction in vision severe enough to require surgery. Cataract is the largest treatable cause of visual loss in childhood. Paediatric cataracts provide different challenges to those in adults. Intense inflammation, amblyopia and posterior capsule opacification can affect results of treatment. Two treatments commonly considered for congenital cataract are lensectomy and lens aspiration.

Objectives

The objective of this review was to assess the effects of surgical treatments for bilateral symmetrical congenital cataracts. Success was measured according to the vision attained and occurrence of adverse events.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochane Library, which contains the Cochrane Eyes and Vision Group Trials Register (2005, Issue 2), MEDLINE (1966 to June 2005), EMBASE (1980 to June 2005, week 27), LILACS (6 July 2005), the Science Citation Index and the reference list of the included studies. We also contacted trial investigators and experts in the field for details of further studies.

Selection criteria

We included all prospective, randomised controlled trials that compared one type of cataract surgery to another, or to no surgery, in children with bilateral congenital cataracts aged 15 years or younger.

Data collection and analysis

Two authors extracted data. No meta-analysis was performed.

Main results

Four trials met the inclusion criteria. All trials were concerned with reducing the development of visual axis opacification (VAO). This was achieved with techniques that included an anterior vitrectomy or optic capture. Posterior capsulotomy alone was inadequate except in older children.

Authors' conclusions

Evidence exists for the care of children with congenital or developmental bilateral cataracts to reduce the occurrence of visual axis opacification. Further randomised trials are required to inform modern practice about other concerns including the timing of surgery, age for implantation of an intraocular lens and development of long-term complications such as glaucoma and retinal detachment.

 

Plain language summary

Surgery for cataracts that develop in both eyes at or soon after birth

To have a cataract describes a condition where the normally clear lens inside the eye is cloudy and obscures vision. Cataracts that develop at or soon after birth in both eyes are a major cause of childhood blindness in the world, especially in developing countries. Treatment is indicated if the cataract prevents normal vision. This can be assessed by measuring how much the child can see and looking into the eye at the cataract. The only way to correct the cataract is to surgically remove it. It is generally accepted that early surgery results in a greater chance of good vision. There are two main approaches to surgery: lensectomy and lens aspiration. Lensectomy removes the entire lens and some of the gel which fills the eye (anterior vitrectomy); lens aspiration removes the lens but leaves the posterior lens capsule intact. A significant complication from surgery is re-clouding of the central passage for vision (visual axis opacification (VAO)). All surgical procedures aim to reduce this and the need for further treatment. Removing the cataract leaves the eye without the ability to focus. This must be corrected as soon as possible after surgery using intraocular lenses (IOL), contact lenses or spectacles, or a combination. The aim of the review was to clarify which surgical approach resulted in the best visual improvement. We searched for studies where children with cataract at or soon after birth had been randomised to receive a type of surgical procedure. The primary outcome was the level of vision after surgery. In the four included randomised studies the type of surgical procedure made no real difference to the final vision but there were differences in the number of children who developed VAO. Procedures which appeared to reduce VAO were anterior vitrectomy (removing some of the gel which fills the eye) and optic capture (lodging the lens portion of the IOL into an opening created in the posterior capsule). Three of the four studies used IOLs to correct aphakia, an option increasingly popular but which may not be suitable in regions where careful follow up cannot be guaranteed. While there is evidence for successful surgical treatment of this type of potentially blinding cataract, there is a lack of good evidence regarding aspects of its delivery such as the best timing for surgery and the appropriate method for aftercare.

 

摘要

背景

先天性雙側白內障的手術方式

先天性白內障是指小孩子單側或雙側眼睛的水晶體變混濁，導致視力減退到需要手術的地步。在兒童時期裡可治療的視力受損族群中，白內障佔了最大的一部分。兒童白內障和成人的相比有著不同的挑戰。嚴重發炎反應、弱視以及水晶體後囊混濁皆可能影響治療的結果。水晶體切除術以及水晶體抽吸術是先天性白內障的常見治療方式。

目標

這篇文獻回顧旨在評估手術治療雙側先天性白內障的效果。成功與否則根據視力的回復以及副作用的發生率。

搜尋策略

我們找了The Cochane Library裡的Cochrane Central Register of Controlled Trials (CENTRAL)。裡面包含了Cochrane Eyes 、 Vision Group Trials Register (2005, Issue 2)、 MEDLINE (1966 ∼2005/6)、 EMBASE (1980∼ 2005/6, week 27)、LILACS (2005/7/6)、 Science Citation Index 以及這些研究的引用紀錄。我們同時也接觸了這些試驗的研究者以及在這個領域的專家來討論其深入研究的細節。

選擇標準

我們選擇前瞻性隨機控制試驗，有關年紀在十五歲以下有雙側先天性白內障的小孩，比較白內障手術之間差異、或不手術的預後。

資料收集與分析

兩位作者負責選擇資料，沒有使用metaanalysis進行分析。

主要結論

有四個試驗符合了選擇標準。裡面所有的試驗都在研究關於減少視軸混濁的發生。使用前玻璃體切除術或是將人工水晶體放置在把開洞的後囊上來達成目的。單獨使用後囊切開術只適用在較大的孩子。

作者結論

證據顯示先天性白內障或雙側發育性白內障的小孩減少視軸混濁發生的照護方式。我們需要更進一步隨機試驗的研究來告知我們有關於其他議題，如手術的時機、植入人工水晶體的年齡、以及長期併發症如青光眼以及視網膜剝離。

翻譯人

本摘要由高雄榮民總醫院畢勇賢翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

白內障是指眼睛裡正常清澈的水晶體變混濁而導致視力模糊。在出生時或者出生後不久發展出白內障，是兒童期失明的主要原因，特別在開發中國家。如果白內障導致視力不良時，即可開始治療。我們可利用小孩視力以及可看進眼睛的程度來評估白內障。治療白內障唯一方式是手術移除。一般認為早期手術有較大的機會讓視力恢復。手術主要有兩種方式：水晶體切除術及水晶體抽吸術。水晶體切除術是移除整個水晶體以及部分眼睛裡的膠體(前玻璃體切除)。水晶體抽吸術是移除水晶體但留下了水晶體後囊。手術後顯著的併發症為視軸混濁。所有的手術步驟旨在減少視軸混濁及更多的治療。移除水晶體將使眼睛無法聚焦。手術後必須儘早使用人工水晶體、隱形眼鏡、一般眼鏡或是上述組合來矯正。本篇目的在釐清何種手術方式會有較好的視力。我們搜尋那些在出生時或出生後不久發展出白內障的小孩子做一個隨機分配來接受不同的手術方式。主要結果以術後視力恢復程度來表示。這四個隨機試驗顯示，在最終的視力並沒有沒有明顯差異，但在小孩發生視軸混濁機會有差異。減少視軸混濁的手術有前玻璃體切除術(移除眼睛中部分的膠體)及將人工水晶體放置在把開洞的後囊上。四篇中有三篇使用人工水晶體來治療無水晶體，這是一種逐漸普及的選擇，但對於沒有辦法仔細追蹤的地區來說並不適合。雖有證據顯示，可能致盲的白內障可用手術成功治療，但最佳的手術時機及術後照護的最適方式，仍缺乏良好證據。