The evaluation of choroidal thickness of patients with ranibizumab resistant diabetic macular edema after intravitreal dexamethason implant or intravitreal aflibercept injections

The purpose of the study was to evaluate the subfoveal choroidal thicknesses of patients with ranibizumab resistant diabetic macular edema (DME), treated with intravitreal dexamethasone (İVD) or intravitreal aflibercept (IVA) and to compare the subfoveal choroidal thickness (SFCT) after different treatments. Also, the correlation between choroidal thickness and change in visual acuity and central retinal thickness (CRT) was investigated. Fifty-two patients with resistant DME after 6 doses of intravitreal ranibizumab (IVR) and 25 healthy subjects were included in the study. Twenty-seven patients were administered IVA after IVR, 25 patients İVD treatment after IVR. Detailed ophthalmologic examinations of all patients were done. The SFCT of the patients and the control group with healthy subjects were measrued using spectral-domain enhanced depth imaging optical coherence tomography (SD-EDI OKT) (Heidelberg Spectralis, Heidelberg Engineering, Heidelberg, Germany). In the retrospectively evaluated medical records, the functional and morphological findings best corrected visual acuity (BCVA), intraocular pressure (IOP), CRT obtained by SD-OCT and SFCT obtained by SD-EDI OKT (Heidelberg Spectralis, Heidelberg Engineering, Heidelberg, Germany), before and after IVD or IVA were evaluated. The findings of the subjects 1 day before IVD or IVA injection and the findings at 1st, 2nd and 3rd months after injection were analyzed. When the SFCT values before IVD injection (1) and after IVD injection (2=1st month, 3=2nd month, 4=3rd month) were compared, the differences between 1/2, 1/3, 1/4 were found statistically significant (p=0.0001 for all). Also, statistically significant differences were found between 2/3, 2/4 and 3/4 periods (p=0,0001; 0,0001; 0,006 respectively). When the SFCT values before IVA injection (1) and after IVA injection (2=1st month, 3=2nd month, 4=3rd month) were compared, the differences between 1/2, 1/3, 1/4 were found statistically significant (p=0.0001 for all). Also, statistically significant differences were found between 2/3, 2/4 and 3/4 periods (p=0,0001; 0,014; 0,0001 respectively). When the BCVA values before IVD injection (1) and after IVD injection (2=1st month, 3=2nd month, 4=3rd month) were compared, the differences between 1/2, 1/3, 1/4 were found statistically significant (p=0.0001 for all). Also, statistically significant differences were found between 2/3, 2/4 and 3/4 periods (p=0,0001; 0,0001; 0.032 respectively). When the BCVA values before IVA injection (1) and after IVA injection (2=1st month, 3=2nd month, 4=3rd month) were compared, the differences between 1/2, 1/3, 1/4 were found statistically significant (p=0,0001; 0,0001; 0,0001 respectively). Also, statistically significant differences were found between 2/3, 2/4 periods (p=0,0001; 0,0001 respectively) while no significant difference was observed between 3/4 periods (p=0,057). When CRT values before IVD injection (1) and after IVD injection (2=1st month, 3=2nd month, 4=3rd month) were compared, the differences between 1/2, 1/3, 1/4 were significant (p=0.0001 for all), while no significant difference was observed between 2/3, 2/4 and 3/4 periods (p=0,9; 0,9; 1,0 respectively). When CRT values before IVA injection (1) and after IVA injection (2=1st month, 3=2nd month, 4=3rd month) were compared, the differences between 1/2, 1/3, 1/4 were significant (p=0.0001 for all), while no significant differences was obtanined between 2/3, 2/4 and 3/4 periods (p=0,9; 0,9; 1,0 respectively). In conclusion, in DME patients resistant to multiple IVR injections, both IVD and IVA injections lead to a decrease in SFCT and a significant increase in BCVA after 3 months of follow-up. Decrease in CRT shows a significant correlation with BCVA increase. While the decrease in SFCT continues, the CRT stabilizes. Our data should be supported with prospective randomized studies with longer follow up periods.