The study was conducted retrospectively in the form of a patient card scan between May 2018 and January 2019 at Manisa Celal Bayar University Department of Ophthalmology Retina Unit. Ethical committe approval was obtained from our institution and the study was conducted under the tenets of Helsinki decleration (Ethics no: 25/06/2019/ 20.478.486).
The study included 45 patients who were treated for DME with anti VEGF- ranibizumab, 52 patients who received SML after intravitreal ranibizumab injection therapy for DME treatment.
The study excluded patients under 18 years of age, with a condition that could reduce visual acuity other than diabetic retinopathy ( Patients with vein occlusion, age-related macular degeneration, epiretinal membrane, vitreomacular traction, amblyopia, optic neuropathy, glaucoma, corneal opacity, ocular trauma ) and macular ischemia. Those who had ocular surgery or conventional retinal photocoagulation in 6 months before or during the treatment, and a history of focal laser treatment with conventional laser were not included in the study.
Best corrected visual acuity (BCVA), central macular thickness (CMT) and macular volumes (MV) measured by Cirrus HD OCT (Carl Zeiss Meditec, Germany) were recorded at the initial examination and monthly controls of all patients. FFA imaging was performed with Visucam 524 (Carl Zeiss Meditec, Germany) and Heidelberg Spectralis HRA (Heidelberg Engineering, Heidelberg, Germany).
All patients received three monthly doses of loading intravitreal ranibizumab injections (0.5 mg / 0.05 mL; Lucentis, Genentech).
Group A was defined as patients who had a SMC 350µm at the third dose intravitreal intravitreal ranibizumab injection control visit, who underwent SML and received ranibizumab in monthly retinal controls when necessary. Group B was defined as patients who had a CMT ≤350µm at the control visit of the third dose of intravitreal ranibizumab injection and who received only PRN ranibizumab injection during monthly retinal controls. Age, gender, systemic disease histories, previous ocular surgery, and PRP treatments of both groups were recorded from follow-up cards. Total number of intravitreal ranibizumab injections at the end of the follow-up period were recorded.
In patients who underwent SML, a fundus image was obtained Visucam fundus camera. MPL (Supra Scan, Quantel Medical, Clermont-Ferrand, France) 577 nm was applied with an Area Centralis lens (Volk Optical, Mentor, OH, USA, 0.94 magnification) after topical anesthesia with proparacaine hydrochloride (Alcaine). Laser parameters were spot diameter 165 µm, 5% DC (duty cycle), 200 ms duration. Laser power was first increased up to the power to create a vague spot in titration spots in the retinal area in the two disc periphery of the posterior pole, then power was reduced to half, and the automatic grid pattern in laser machine was applied. If necessary additional focal laser was applied to the areas with increased retinal thickness in OCT imaging.
The compliance of continuous numerical data to normal distribution was decided by evaluating the Shapiro-Wilk test and histogram. Student t test was used for comparisons in two independent groups for continuous numerical variables conforming to normal distribution, ANOVA for repeated measures and ANOVA for two-factor repetitive measurements were used for dependent group comparisons with more than two groups, and their mean values were compared. In cases where normal distribution conditions were not met, Mann Whitney U test was used to compare two independent groups, and Friedman test was used to compare multiple measurements, and median values were compared. In the analysis of the data, Statistical Package of social science (SPSS, Chicago, inc, USA version 21.0) was used in analysis of the collected data and a statistically p value of <0.05 was considered significant.