Multifocal versus monofocal intraocular lenses after cataract extraction

 

Abstract

Background

Good unaided distance visual acuity is now a realistic expectation following cataract surgery and intraocular lens (IOL) implantation. Near vision however still requires additional refractive power usually in the form of reading glasses. Multiple optic (multifocal) IOLs are available which claim to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal IOLs.

Objectives

The objective of this review was to assess the effects of multifocal IOLs, including effects on visual acuity, subjective visual satisfaction, spectacle dependence, glare and contrast sensitivity, compared to standard monofocal lenses.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which includes the Eyes and Vision Group Trials Register) on The Cochrane Library (2006, Issue 3), MEDLINE (1966 to July 2006), EMBASE (1980 to July 2006), NRR (2006, Issue 3) and PUBMED searched on 25 July 2006, limit: 90 days (entry date). We searched the reference lists of relevant articles and contacted investigators of included studies and manufacturers of multifocal intraocular lenses for information about additional published and unpublished studies.

Selection criteria

All randomised controlled trials comparing a multifocal IOL of any type with a monofocal IOL as control were included. Both unilateral and bilateral implantation trials were included.

Data collection and analysis

Data were collected and trial quality was assessed. Where possible, statistical summary measures were calculated otherwise data were tabulated.

Main results

Ten trials were identified, and a further three are pending review. There was significant variability between the trials in which outcomes were reported. Unaided distance acuity was similar in multifocal and monofocal IOLs (standardised mean difference (SMD) 0.03, 95% Confidence Interval (CI) -0.13 to 0.19). There was no statistical difference between multifocal IOLs and monofocals with respect to the proportion of participants achieving 6/6 best corrected visual acuity (Peto odds ratio (OR) 1.05, 95% CI 0.67 to 1.63). Unaided near vision was improved with the multifocal IOLs. Total freedom from use of glasses was achieved more frequently with multifocal than monofocal IOLs (OR for spectacle dependence 0.17, 95% CI 0.12 to 0.24). Adverse effects included reduced contrast sensitivity and the subjective experience of haloes around lights.

Authors' conclusions

Multifocal IOLs are effective at improving near vision relative to monofocal IOLs. Whether that improvement outweighs the adverse effects of multifocal IOLs will vary between patients. Motivation to achieve spectacle independence is likely to be the deciding factor.

 

Plain language summary

A comparison of multifocal and monofocal intraocular lens implants used in cataract surgery

Cataract, defined as the presence of visually-impairing lens opacity in one or both eyes, is present in 30% of persons of 65 years and over in the UK. Modern cataract surgery is frequently accompanied by the insertion of an implant within the eye known as an intraocular lens. Monofocal intraocular lenses have one point of focus. Monofocal intraocular lenses can be used to give clear point of focus in the distance or close up, but you can only choose one focal point. Glasses provide extra lens power which enables focussing at other points in space, such as close up for reading. Multifocal intraocular lenses were designed to avoid the need for glasses by providing two or more points of focus. This review identified 10 trials, and a further three are pending review, comparing monofocal to multifocal intraocular lenses. Unfortunately near vision and subjective outcomes were poorly assessed in these trials. The distance vision without glasses was similar in both groups. Near vision without glasses, however, was better in the multifocal group and participants in this group were more likely to achieve total freedom from glasses. Multifocal intraocular lenses had drawbacks; they were associated with symptoms of halos around lights, and a reduced contrast sensitivity (the ability to distinguish an object against a background which is similar to the object itself). Thus multifocal intraocular lens implants reduce spectacle dependence after cataract surgery but at the expense of clarity. Ultimately it will be up to the individual to decide which type of lens they would prefer.

 

摘要

背景

白內障摘除術後置放多焦點對照單焦點人工水晶體

現實中期望白內障手術與人工水晶體植入(intraocular lens (IOL))後可以有良好的遠距裸視。然而近視仍然需要以老花眼鏡來獲得更多的屈光力。現有的多焦點(multifocal)IOLs其聲稱可以在一範圍的距離下有良好的視力。但目前不清楚是否多焦點IOLs的效益大於可妥協的固有缺點。

目標

這篇回顧的目的是評估多焦點IOLs相對於標準的單焦點水晶體的效果，包括視力，主觀的視力滿意度，眼鏡依賴，眩光與對比敏感度。

搜尋策略

我們檢索the Cochrane Central Register of Controlled Trials (CENTRAL) (其包含考科藍圖書館的the Eyes and Vision Group Trials Register) (2006年，第3期)， MEDLINE (1966至2006年7月), EMBASE (1980至2006年7月), NRR (2006年，第3期)並於2006年7月25日檢索PUBMED，限制：90天(登錄日期)。我們檢索相關文章的參考文獻並連絡納入研究的研究人員與多焦點人工水晶體的廠商以獲得更多已發表與未發表研究的資訊。

選擇標準

納入所有比較任何類型多焦點IOLs與單焦點IOL作為對照組的隨機對照試驗。

資料收集與分析

蒐集資料並評估研究品質。如果可以的話，計算統計學統整的測量結果，否則資料以表列呈現。

主要結論

確定10篇試驗，另外三篇正在等待審核。試驗間報告的結果具有顯著變異性。多焦點與單焦點IOLs組其遠距裸視是相同的(standardised mean difference (SMD)為0.03，95% Confidence Interval (CI)為−0.13至0.19)。多焦點與單焦點IOLs組間其研究對象達到6/6最佳矯正視力的比例沒有統計差異(Peto odds ratio (OR)為1.05，95% CI為0.67至1.63)。多焦點IOLs組其近距裸視有獲得改善。多焦點比單焦點IOLs有較多完全不使用眼鏡的風險(眼鏡依賴的OR為0.17，95% CI為0.12至0.24)。副作用包括減少對比敏感度與主觀的光暈眩的經驗。

作者結論

相對於單焦點IOLs，多焦點IOLs對於改善近視具有效果。不論多焦點IOLs的改善效果大於副作用的情況是否在病患間會有所不同。達到不依賴眼鏡的動機有可能是決定的因素。

翻譯人

本摘要由高雄榮民總醫院金沁琳翻譯。

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

總結

比較白內障手術中植入多焦點與單焦點人工水晶體。白內障定義為一眼或雙眼存在著視力受損的不透明狀水晶體，在英國有30%的65歲以上人口罹患白內障。現代的白內障手術通常伴隨著將稱為人工水晶體的種植體植入眼睛。單焦點人工水晶體有一個聚焦點。單焦點人工水晶體可以給予清楚的遠距或近距的聚焦點，但只可以選擇一個聚焦點。眼鏡提供了額外的透鏡光學能力以使在空間的其他點形成聚焦，如近距離閱讀。多焦點人工水晶體被設計用來提供兩點或多點的聚焦以避免眼鏡的需要。這篇回顧確定了10篇比較單焦點與多焦點人工水晶體的試驗，而另外三篇正等待審核。不幸地，這些試驗中評估近視與主觀的結果不佳。兩組中不戴眼鏡的遠距視力相同。然而，多焦點組中其不戴眼鏡的近距視力較佳，且這組的研究對象較有可能完全不使用眼鏡。多焦點人工水晶體具有缺點；它們與光暈眩的症狀有關，且會減少對比敏感度(區分物體與物體本身相似背景的能力)。因此白內障手術後植入多焦點人工水晶體可以減少眼鏡依賴，但花費較高。最終將由個人決定他們較偏好何種類型的人工水晶體。