Microperimetry and mfERG as functional measurements in diabetic macular oedema undergoing intravitreal ranibizumab treatment

Abstract

Purpose To evaluate Microperimetry (MP) and multifocal electroretinogram (mfERG) as whole-macula functional markers of treatment response in naive diabetic macular oedema (DMO) patients undergoing ranibizumab treatment. Methods An exploratory sub-analysis of a prospective study (NCT01947881-CHARTRES). Patients received three monthly ranibizumab injections (loading dose) followed by pro re nata (PRN) regimen during 1 year. At baseline, during and after treatment (Months 0, 3, 6 and 12), subjects were tested using BCVA, OCT, MP and mfERG. MP was performed in the central 12°, and retinal sensitivity was measured overall (mean sensitivity (MS)), and in three concentric rings (R1-R3). mfERG P1 amplitude and implicit time were measured over six concentric rings (R1-R6). Results Thirty-two eyes were included. MP mean and rings sensitivity were significantly lower in DMO (p < 0.001). After loading dose, a significant improvement in retina sensitivity was observed, particularly in good BCVA responders (MS = +2.28 dB; R1 = +2.33 dB, R2 = +2.20 dB, R3 = +2.25 dB; p = 0.049). Overall retinal sensitivity was significantly correlated with BCVA improvement (r = 0.54; p = 0.026) and inversely correlated with OCT central subfield thickness improvement (r = −0.39; p = 0.026). mfERG amplitude and implicit time were also lower in DMO (p < 0.011). An improvement of mfERG P1 amplitude and implicit time in R1 was noted in good responders after ranibizumab loading dose (+16.49 nV/deg 2 ; p = 0.013 and −0.005 ms; p = 0.048, respectively). When changing to PRN treatment regimen, BCVA was maintained during the 12 months of follow-up but worsening of the visual function was detected by MP and mfERG. Conclusions Microperimetry and mfERG were able to demonstrate DMO functional improvement after treatment loading dose, as well as early visual changes when treatment regimen was switched to PRN.

The Retinal Posterior Pole in Early Parkinson’s Disease: A Fundus Perimetry and SD-OCT Study

“…Santos et al compared the results between mfERG and FP in diabetic macular edema and concluded that both were able to demonstrate a functional improvement after intravitreal treatment with ranibizumab. 47 In general, fundus perimetry seems to perform as well as electrophysiology examination in detecting retinal alterations in different pathologies.…”

Microperimetry in Retinal Diseases

“…5). 48,65,66 In the ProgStar6 and Tanna et al64 studies, the baseline VTOT in adults was 0.91 and 0.52 dB-sr with an annual decline of 0.077 to 0.06 dB-sr, respectively. In children, these values were a baseline VTOT of 0.87 dB and an annual decline of 0.21 dB-sr.…”

“…In addition, Santos and colleagues reported that better retinal sensitivities before treatment were associated with better BCVA outcomes after therapy. This suggested that the baseline MP findings may have prognostic value for DME treatments 89. Yohannan et al90 further demonstrated that disruption of the ellipsoid zone is correlated with a significant decrease in the point sensitivity in eyes with DME.…”

“…For example, in diabetic macular edema (DME), the retinal sensitivities determined by MP coupled with optical coherence tomography (OCT) biomarkers and multifocal electroretinograms are used as functional markers for the entire macula region. Thus, earlier studies have shown that MP, together with these other methods, were able to show improvements in sensitivity following anti-VEGF therapy by ranibizumab or aflibercept in eyes with DME 6,7. Furthermore, the macular function assessed by MP combined with structural OCT angiography (OCTA) metrics and capillary dropout areas showed low sensitivities in eyes with ischemic DME 8.…”

“…In addition, following treatment with anti-VEGF agents or intravitreal corticosteroids, improvements in retinal sensitivities have been reported 82–84. The retinal sensitivity improvement was significantly correlated with the BCVA and inversely correlated with the OCT central subfield thickness 85–88. In addition, Santos and colleagues reported that better retinal sensitivities before treatment were associated with better BCVA outcomes after therapy.…”