Dear Editor,Diabetic retinopathy is a common complication of diabetes which can result in blindness. Studies have generally shown that visual outcomes after cataract surgery in patients with diabetes are worse than in non-diabetics, especially those with diabetic retinopathy. [1][2][3] In patients with diabetic retinopathy, a major cause of unfavourable outcomes after cataract surgery is macular oedema. 4 Factors associated with significant macular oedema include the duration of diabetes, glycaemic control, degree of retinopathy, and macular oedema at the time of surgery. 4,5 Increased retinopathy progression and increased incidence of macular oedema after cataract surgery have been reported in patients with diabetes, 1 while other studies have not reported these findings. 6 Some authors suggested that the findings are due to the natural course of diabetes. 5,7 To this end, we performed a meta-analysis to determine outcomes of cataract surgery in diabetic patients with diabetic retinopathy as compared to those without retinopathy.
Materials and MethodsMedline, Cochrane, and Google Scholar databases were searched from inception until January 30, 2015 using combinations of the following keywords: visual outcome, cataract surgery, diabetes, diabetic retinopathy. Inclusion criteria for the meta-analysis were: 1) two-arm studies; 2) one group of eyes that had diabetic retinopathy and another that did not; 3) that both groups of eyes had undergone cataract surgery; 4) quantitative outcomes that had been reported. Single-arm studies and those with patients receiving medical treatment (enoxaparin, ranibizumab, or triamcinolone, etc.) in addition to cataract surgery to prevent macular oedema were excluded. Letters, comments, editorials, case reports, proceedings, and personal communications were also excluded. Studies were identified by the search strategy via two independent reviewers. Information/data extracted from studies that met the inclusion criteria were: the name of the first author, year of publication, study design, number of participants in each group, participants' age and gender, presence of retinopathy and the major outcomes. The method described by Hayden et al 8 was used to assess the quality of the included studies.Outcome measures were: 1) percentage of eyes with