الفهرس 
? Diabetic macular oedemaOnly 14 pages are availabe for public view
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Abstract
Purpose: To evaluate the effectiveness of subthreshold micropulse laser as compared to intravitreal injection of ranibizumab in treatment of center involving diabetic macular oedema.
Methods: A total of 76 eyes of 62 patients with center involving diabetic macular oedema were divided into two groups. group A received intravitreal injection of ranibizumab while group B received subthreshold micropulse laser with rescue intravitreal injection of ranibizumab. The change from baseline in best correscted visual acuity and central subfield thickness were compared at 3, 6, 9 and 12 months follow-up. Any adverse effects were recorded.
Results: group A (n=34 eyes) experienced a statistically significant improvement in best corrected visual acuity (from 0.32±0.16 Log MAR at baseline to 0.21±0.14 Log MAR at 12 months) (P value =0.006), with a statistically significant reduction in central subfield ghickness (from 352.06±34.34µm to 289.47±58.88 µm) (P value=0.001). group B (n=42 eyes), also experienced a statistically significant improvement in best corrected visual acuity (from 0.34±0.22 Log MAR at baseline to 0.13±0.31 Log MAR at 12 months) (P value=0.001), with a statistically significant reduction in central subfield thickness (from 300±47.34µm to 253.12±39.60 µm at 12 months) (P value= 0.009). The mean difference in best corrected visual acuity between the group B and group A was -0.08 Log MAR with a 95% CI ranging from -0.197 to 0.037, which supports the claim of non-inferiority between the two treatment regimens. No adverse effects from subthreshold micropulse laser were recorded in both groups.
Conclusion: subthreshold micropulse laser with rescue intravitreal injection of ranibizumab was non inferior to intravitreal injection of ranibizumab in treatment of center involving diabetic macular oedema as regards the mean change in best corrected visual acuity.
Introduction
T
he management of diabetic macular oedema (DME) has substantially changed over the years due to the advancement in pharmacotherapy with intravitreal injections (IVI) of anti-vascular endothelial growth factor (VEGF). However, the traditional laser treatment proposed by the Early Treatment Diabetic Retinopathy Study (ETDRS) is still being used for its efficacy, low cost and easy processing.
Despite the improvements and the satisfactory results of laser photocoagulation, adverse events such as central scotoma, loss of central vision, decreased color vision, preretinal and subretinal fibrosis and choroidal neovascularization can still occur, mostly caused by permanent destruction of the photoreceptors and the progressive enlargement of the laser scars, consequent to the visible burn endpoint of conventional threshold laser photocoagulation1-2-3-4.
Results of the diabetic retinopathy clinical research (DRCR) network protocol I trial showed that intravitreal Ranibizumab (a humanized monoclonal antibody fragment which competitively inhibits VEGF in the extracellular space), with prompt or deferred laser was more effective compared with prompt laser alone for the treatment of DME involving the central macula after one year follow up, and that the vision gains were maintained through 5 years follow up with little additional treatment needed after 3 years 5-6.
Several other studies have been conducted to investigate the efficacy and safety of Intravitreal Ranibizumab in treatment of DME including the READ-2 study, the RESOLVE study, the RESTORE study and the RISE and RIDE studies which showed that ranibizumab is effective in improving best corrected visual acuity (BCVA) and is well tolerated in DME7-8-9-10.
Although Ranibizumab was demonstrated to be effective, a major concern, is that DME will return as the effect of the intravitreal drug lessens, necessitating repetitive long term injections. Another concern is the financial burden of repeated intravitral injections of ranibizumab. That led to the emergence of new modalities of laser treatment for management of diabetic retinopathy (DR), including selective retinal therapy (SRT) and subthreshold micropulse laser (STMPL) in which the modification of laser parameters and using selective laser wave lengths can produce less destructive and more therapeutic effect.
The state of the art of STMPL has been shown to be effective in the treatment of DME in terms of BCVA, central macular thickness (CMT), and macular sensitivity11-12-13-14. STMPL has also been suggested to have anti-inflammatory effects reducing the number of hyper-reflective spots (sign of activated microglia cells in the retina), microaneurysms, disorganization of the inner retinal layers extension, and the area of cysts15. Also, several prospective randomized trials have reported equal improvement in BCVA and retinal thickness between STMPL and conventional ETDRS laser photocoagulation in DME16-17-18-19-20.