Evaluation of inner and outer retinal thickness in patients receiving intravitreal ranibizumab injections for diabetic macular edema

Abstract

Purpose: To measure inner and outer retinal thickness with optical coherence tomography (OCT) in patients in whom intravitreal ranibizumab was administered due to diabetic macular edema (DME) and to investigate its relation to the visual prognosis. Methods: In this retrospective case series, there were 60 consecutive eyes with DME in which intravitreal ranibizumab injection was performed for 3 times in 1-month intervals. All patients underwent full ophthalmic examination and spectral-domain OCT (SD-OCT). The total retinal thickness, the inner thickness, and the outer thickness in 4 parafoveal subfields were measured. The correlation between the retinal thickness and logMAR best-corrected visual acuity (BCVA) was investigated. Results: No significant correlation was found between the total retinal thickness in the central and other subfields and either the baseline or final visit logMAR BCVA values (p>0.05). There was a significant positive correlation between the final visit logMAR BCVA values and pretreatment inner retinal thickness in the nasal and inferior subfields (r = 0.270, p = 0.037, and r = 0.410, p = 0.001, respectively). There was significant negative correlation between the final visit logMAR BCVA values and pretreatment outer retinal thickness in nasal and temporal parafoveal subfields (r = -0.297, p = 0.021, and r = -0.268, p = 0.038, respectively). Conclusions: It could be beneficial to use inner and outer retinal thickness instead of total retinal thickness in determination of short-term prognosis in patients who had intravitreal ranibizumab injection for DME.