Virgili G, Menchini F
University of Florence, Eye Clinic II, Department Oto-Neuro-Ophthalmological Surgical Sciences, Via le Morgagni 85, Florence, Italy 50134.
Cochrane Database Syst Rev. 2005 Oct 19(4):CD004765. doi: 10.1002/14651858.CD004765.pub2.
Pathologic myopia is usually defined as the need for a spectacle correction of -6 diopters or higher. Choroidal neovascularisation (CNV) is the most commonly occurring cause of visual loss in people with pathologic myopia. In myopic macular degeneration the occurrence of newly formed vessels in the macula often leads to a fibrotic pigmented scar causing a blind spot in the centre of the visual field.
The primary objective of this review was to examine the effects of laser photocoagulation for CNV associated with pathologic myopia. A secondary objective was to compare the effects of different photocoagulation techniques.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) on The Cochrane Library (Issue 2, 2005), MEDLINE (1966 to July 2005), EMBASE (1980 to July 2005, week 28), LILACS (July 2005) and the reference lists of included studies.
We included randomised controlled trials comparing photocoagulation with observation or comparing different photocoagulation techniques in people with CNV associated with myopia of -6 diopters or higher.
Two authors independently assessed the search results for eligibility.
Two studies were included that enrolled people with CNV located at 100 microns or more from the foveal centre. One study compared photocoagulation with observation. At the final examination, 16/35 participants randomised to photocoagulation versus 31/35 randomised to observation had visual acuity of 20/100 or worse after 6 to 48 months. The second study randomised 27 eyes (26 patients) to photocoagulation with three laser wavelengths (9 eyes per group). The number of eyes losing two or more lines was 2 (577 nm), 3 (590 nm) and 3 (620 nm) after 3 to 17 months. In both studies comparisons were made using outcomes assessed at the final examination. As the final examination took place at different follow-up times it was difficult to interpret the findings and it was impossible to extract data for further analyses.
AUTHORS' CONCLUSIONS: Despite its use over several years the effectiveness of laser photocoagulation for myopic CNV has not been established. Although there was a suggestion of short-term effectiveness in one small study on non-subfoveal CNV the results were potentially biased. Observational studies suggest that the enlargement of the atrophic laser scar after laser treatment of non-subfoveal CNV could be a potentially vision-threatening long-term complication, even in eyes free of CNV recurrence.
病理性近视通常定义为需-6屈光度或更高的眼镜矫正。脉络膜新生血管形成（CNV）是病理性近视患者视力丧失最常见的原因。在近视性黄斑变性中，黄斑区新形成血管的出现常导致纤维化色素性瘢痕，在视野中心形成盲点。
本综述的主要目的是研究激光光凝治疗与病理性近视相关的CNV的效果。次要目的是比较不同光凝技术的效果。
我们检索了Cochrane对照试验中心注册库（CENTRAL）（其中包含Cochrane眼科和视力组试验注册库），该库收录于《Cochrane图书馆》（2005年第2期）、MEDLINE（1966年至2005年7月）、EMBASE（1980年至2005年7月，第28周）、LILACS（2005年7月）以及纳入研究的参考文献列表。
我们纳入了比较光凝与观察或比较不同光凝技术的随机对照试验，试验对象为近视度数-6屈光度或更高且伴有CNV的患者。
两位作者独立评估检索结果的合格性。
纳入了两项研究，研究对象为CNV位于距黄斑中心100微米或更远的患者。一项研究比较了光凝与观察。在最终检查时，随机分配至光凝组的35名参与者中有16名，随机分配至观察组的35名参与者中有31名在6至48个月后视力为20/100或更差。第二项研究将27只眼（26名患者）随机分为三组，分别接受三种激光波长（每组9只眼）的光凝治疗。3至17个月后，视力下降两行或更多行的眼数分别为：577纳米组2只，590纳米组3只，620纳米组3只。在两项研究中，均使用最终检查时评估的结果进行比较。由于最终检查在不同的随访时间进行，因此难以解释研究结果，也无法提取数据进行进一步分析。
尽管激光光凝已应用多年，但对于近视性CNV的有效性尚未确立。尽管在一项关于非黄斑中心凹下CNV的小型研究中有短期有效性的迹象，但结果可能存在偏差。观察性研究表明，即使在无CNV复发的眼中，对非黄斑中心凹下CNV进行激光治疗后萎缩性激光瘢痕的扩大可能是一种潜在的威胁视力的长期并发症。
