Steroid injection in addition to macular laser grid photocoagulation in diabetic macular oedema: a systematic review

This study aimed to evaluate the evidence for the effects of steroid injection in addition to macular laser grid (MLG) photocoagulation versus those of MLG photocoagulation alone on visual acuity (VA) in patients with diabetic macular oedema (DMO).

An extensive literature search in Medline (PubMed), Experta Medica (EMBASE) and the Cochrane Library (CENTRAL) using synonyms for MLG photocoagulation, steroid injection and DMO found 181 articles. Of the articles that met selection criteria, three studies in which patients receiving MLG photocoagulation were randomized to additional pretreatment with steroids provided the best available evidence. In addition to VA, central foveal thickness (CFT) was measured at baseline and at 6 months in all three studies.

Two studies, with total populations of 73 and 42 eyes, respectively, reported no additional effect of steroid injection on VA. One study, with a total of 41 eyes, reported a beneficial effect of pretreatment with steroids on VA of -0.21 ETDRS logMAR units. All three studies reported larger reductions in CFT in eyes pretreated with steroids, the smallest of which was 64 microm.

Although there is a greater reduction in CFT in eyes pretreated with steroids, this does not consistently result in higher VA. The literature search does not provide sufficiently strong evidence to recommend steroid injection before MLG photocoagulation in DMO.