Surgical interventions for age-related cataract

 

Abstract

Background

Cataract accounts for 50% of blindness globally and remains the leading cause of visual impairment in all regions of the world, despite improvements in surgical outcomes (WHO 2005). This number is expected to rise due to an aging population and increase in life expectancy. Although cataracts are not preventable, their surgical treatment is one of the most cost-effective interventions in healthcare.

Objectives

To compare the effects of different surgical interventions for age-related cataract.

Search methods

We searched CENTRAL, MEDLINE, EMBASE up to July 2006, NRR Issue 3 2005, the reference lists of identified trials and we contacted investigators and experts in the field for details of published and unpublished trials.

Selection criteria

We included randomised controlled trials (RCTS).

Data collection and analysis

Two review authors independently extracted data and discrepancies were resolved by discussion. Where appropriate, risk ratios, odds ratios and weighted mean differences were summarised after assessing heterogeneity between the studies.

Main results

We identified 17 trials that randomised a total of 9627 people. Phacoemulsification gave a better visual outcome than extracapsular surgery but similar average cost per procedure in Europe but not in poorer countries. Extracapsular surgery with posterior chamber lens implant and ICCE with or without an anterior chamber intraocular lens (IOL) implant gave acceptable visual outcomes but extracapsular surgery had less complications. Manual small incision surgery provides better visual outcome than ECCE but slightly inferior unaided visual acuity compared to phacoemulsification.

Authors' conclusions

This review provides evidence from seven RCTs that phacoemulsification gives a better outcome than ECCE with sutures. We also found evidence that ECCE with a posterior chamber lens implant provides better visual outcome than ICCE with aphakic glasses. The long term effect of posterior capsular opacification (PCO) needs to be assessed in larger populations. The data also suggests that ICCE with an anterior chamber lens implant is an effective alternative to ICCE with aphakic glasses, with similar safety. Phacoemulsification provides the best visual outcomes but will only be accessible to the poorer countries if the cost of phacoemulsification and foldable IOLs decrease. Manual small incision cataract surgery provides early visual rehabilitation and comparable visual outcome to PHACO. It has better visual outcomes than ECCE and can be used in any clinic that is currently carrying out ECCE with IOL. Further research from developing regions are needed to compare the cost and longer term outcomes of these procedures e.g. PCO and corneal endothelial cell damage.

 

Plain language summary

Surgical treatment for cataract caused by aging changes in the lens which reduce its transparency and leads to visual impairment

Cataract is a major cause of global blindness, accounting for 50% to 80% in developing countries. The number of people blind from cataract is expected to rise due to the increase in life expectancy. Aging causes changes in the lens protein leading to opacification of the lens. These changes are often bilateral although maybe asymmetric. Symptoms from cataracts include glare, blurred vision, progressive decrease in visual function and blindness. Surgery is currently the only treatment option once the lens has opacified and vision is decreasing. The indication for surgery is based on whether the patient's reduced visual function interferes with their quality of life. Different surgical techniques have been developed to remove the cloudy lens which is replaced either by an intraocular lens (positioned in the posterior chamber or the anterior chamber of the eye), aphakic glasses or contact lens. There are four main forms of cataract extraction surgery: intracapsular (ICCE), extracapsular (ECCE), phacoemulsification (PHACO) and manual small incision (MSICS). The review authors searched the medical literature and identified 17 randomised controlled trials (9627 participants) investigating the different surgical interventions. Six of these trials suggested that PHACO gives a better outcome than ECCE. They suggest a better uncorrected visual acuity (UCVA) following PHACO than ECCE but the majority of the trials showed no difference in best corrected visual acuity (BCVA) between the two groups. The costs per procedure were not markedly different between the two techniques in a UK based study, however, a Malaysian study showed ECCE to be significantly cheaper. A study comparing MSICS and ECCE, advocated MSICS as the procedure of choice due to equal costs and better visual results. Two studies compared the results of PHACO and MSICS. Phacoemulsification having a significantly higher proportion of patients with UCVA > 6/18 (81.1% versus 71%) but there was no difference in BSCVA. Trials comparing costs of PHACO and MSICS are important for future research. Manual small incision surgery offers an alternative technique in developing countries as it provides acceptable visual outcomes when compared to PHACO yet is likely to be more economical as it avoids the initial outlay of costs of PHACO. It is important to remember that the studies in this review were based in a variety of countries and situations (hospital based or cataract camps); a knowledge of the setting is vital before drawing conclusions from the data.

 

摘要

背景

老化性白內障的外科治療

儘管外科療效有所進步，全球約50%的視盲仍舊是由白內障所致，它同時也一直是世界上所有地區視覺損傷的主要原因。(世界衛生組織2005). 由於人口老化與預期壽命延長，這個數字預計仍會增加。雖然白內障不可預防，但是手術仍是在健康照護中最具成本效益的治療方式。

目標

比較老化性白內障的不同外科治療的療效。

搜尋策略

我們搜尋了CENTRAL, MEDLINE, EMBASE up to July 2006, NRR Issue 3 2005,以及所找到的試驗的參考文獻，並與此領域的研究人員及專家接洽以了解已發表和未發表過的試驗細節。

選擇標準

我們納入了隨機對照臨床試驗。

資料收集與分析

兩位回顧作者分別擷取資料，並在有所不一致時以討論的方式解決。在檢視各研究間的差異性後，risk ratios、odds ratios以及加權後的平均數差都在適當的地方有所總結。

主要結論

我們找到了共隨機分配了9627位病患的17個臨床試驗。Phacoemulsification比extracapsular手術提供較好的視覺結果。在歐洲，兩者的平均單一療程費用是相似的，但在較窮的國家則不然。 加posterior chamber lens 植入的Extracapsular手術與植入或不植入anterior chamber intraocular lens(IOL)的ICCE手術都能達到可接受的視覺結果，但是extracapsular手術有較少的併發症。手工小切口手術比ECCE提供較佳的視覺結果，但是與phacoemulsification相比，則造成略差的裸視視力。

作者結論

這篇回顧根據7個隨機控制試驗結果，與ECCE合併縫合相比較，phacoemulsification 提供更好的結果。我們也發現ECCE 合併posterior chamber lens種植比ICCE合併aphakic glasses提供更好的視覺結果。posterior capsular opacification(PCO)的長期效果需要更多的人口來研究。數據也顯現，與ICCE合併aphakic glasses相較，ICCE合併 anterior chamber lens種植也是一個有效的替代選擇，且一樣安全。phacoemulsification 提供最好的視覺結果，但是如果費用能降低， Phacoemulsification和摺疊式的IOLs將更易被較窮國家引用。相較於PHACO，手工小切口白內障手術提供較快的視覺恢復和可接受的視覺結果，與ECCE相比較，它有更好視覺結果，且可以被目前正在進行的ECCE 合併IOL之任何門診部裡使用。發展中地區需要進一步研究來比較不同手術方法的費用和長期結果。(例如:PCO與角膜內皮細胞損害)

翻譯人

本摘要由高雄榮民總醫院葉宣德翻譯。

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

總結

外科治療老化引起的白內障，而白內障是因為水晶體的透明度降低而導致視覺損傷。白內障是全盲的主要原因，在開發中國家占50%到80%。由於預期壽命的提升，白內障導致視盲的人口數量預計會增加。老化引起水晶體蛋白質變化導致水晶體混濁。這些變化經常是雙側，也可能非對稱。白內障的症狀包括眩目，視覺模糊，視覺功能逐漸降低和視盲。一旦水晶體混濁，視力降低，手術是目前唯一的治療選擇。手術的適應症是病患的視覺功能降低是否已干擾到他們的生活品質。目前已有不同的移除混濁水晶體的外科技術被開發出來，包括用intraocular lens(放置在 posterior chamber or the anterior chamber of the eye), aphakic眼鏡或者隱形眼鏡來替換。白內障有4 個主要抽取手術:intracapsular (ICCE), extracapsular (ECCE), phacoemulsification (PHACO) and manual small incision (MSICS)。回顧作者搜尋醫學文獻並且鑑定17 隨機控制試驗(9627個參加者)來研究不同的手術方法。其中6 個試驗提出PHACO比ECCE提供更好的結果。他們建議PHACO比ECCE有較好的未經矯正的視敏度(UCVA)，但是多數的試驗顯示經矯正視敏度(BCVA)在兩組之間差別不大。一項在英國的研究，每個手術技術費用並無顯著的不同，不過，馬來西亞的研究顯示ECCE 明顯便宜。一項比較MSICS 和ECCE的研究，由於相等的費用和較好視覺結果，建議MSICS作為首選的手術方式。兩項研究比較PHACO以及MSICS的結果，Phacoemulsification有相當高的病患比例>6/18有UCVA (81.1% 與71%)，但是在BSCVA則沒有差別。比較PHACO 和MSICS費用的試驗在未來的研究很重要。手工小切割手術提供開發中國家可接受的視覺結果技術，與PHACO相比，它可能更經濟且避免PHACO的費用。切記，這裡的研究回顧是基於多種國家和情勢(醫院的背景或者白內障陣營);在從數據得出結論之前，背景知識至關重要。