Abstract
Purpose :
To investigate whether different spectral-domain optical coherence tomographic (SD-OCT) patterns of diabetic macular oedema (DME) at baseline are associated with different outcomes in terms of time to recurrence and the features of the phenotype in eyes treated using an intravitreal dexamethasone implant.
Methods :
We performed a retrospective analysis of SD-OCT volume scans of eyes with DME acquired at the time of treatment using a dexamethasone implant and subsequently at monthly intervals until the time of the first recurrence of the DME. Time to recurrence and SD-OCT features of the phenotype were recorded, including the presence of intraretinal cystoid spaces, of subretinal fluid, the integrity of the external limiting membrane (ELM), and that of the ellipsoid zone (EZ, a.k.a. the IS/OS layer). Two main patterns were identified at baseline: intraretinal cysts only (‘IRC’) and intraretinal cysts with concomitant subretinal fluid (‘mixed pattern’).
Results :
Seventy-two eyes of 65 patients were investigated. At baseline, 42 eyes (58.3%) demonstrated an IRC and 30 eyes (41.6%) a mixed DME pattern. In eyes with the IRC pattern, ELM abnormalities were present in 42.8%, and EZ abnormalities in 80.9% of eyes. In eyes with the ‘mixed’ pattern, ELM abnormalities were present in 60% and EZ abnormalities in 76.6% of eyes. The time to first recurrence of the DME was ≥6 months in 19% of eyes with the IRC pattern and in 33.3% eyes with the ‘mixed’ pattern. At the time of first recurrence of the DME, in eyes with the IRC pattern at baseline, ELM abnormalities were present in 50%, EZ changes in 76.2% of eyes. In eyes with the ‘mixed’ pattern at baseline, ELM abnormalities were detectable in 63.3%, EZ changes in 86.6% of eyes. In 24 (80%) of the eyes with a mixed pattern at baseline, recurrence of the DME occurred without the presence of subretinal fluid.
Conclusions :
In DME eyes treated using dexamethasone implants, a ‘mixed’ pattern at baseline was associated with a longer time to recurrence, whereas an IRC pattern was associated with a higher incidence of subretinal fluid at the time of recurrence. SD-OCT characteristics of different DME patterns at baseline can predict morphological features and relative time to recurrence of DME.
This is a 2020 ARVO Annual Meeting abstract.