Abstract
Purpose:
To characterise changes in macular morphology on SD-OCT following intravitreal dexamethasone implant (Ozurdex) for macular oedema in retinal vein occlusion.
Methods:
The changes in morphology of retinal layers at macula on SD-OCT at 6 months following lntravitreal Ozurdex in retinal vein occlusion (19 BRVO, 11 CRVO) were assessed retrospectively. Each scan was analysed at 4 intersection points of the ETDRS grid 1mm from the centre. The following morphological classification to analyse the presumed retinal layers was used. Nerve fibre layer (NFL) was recorded as normal, thickened or thinned; ganglion cell-inner plexiform layer (GCL+IPL) and the outer plexiform-outer nuclear layer (OPL+ONL) were graded as intact, cystoid or diffuse oedema or mixed. The integrity of the external limiting membrane and ellipsoid layer were classified as intact, disrupted or absent. Each layer was individually analysed for changes from the baseline to six months post treatment
Results:
Of 30 eyes NFL was intact in 80%, thickened in 13% and thinned in 2% at baseline. At six months NFL was intact in 80%, thickened in 17% and thinned in 3%. At baseline GCL+IPL layer was intact in 13% eyes, cystic in 37%, diffuse in 27% and mixed in 23% eyes. At 6 months, GCL + IPL was intact in 13%, cystic in 3%, diffuse in 57% and mixed in 27% eyes. Thus the 34% decrease in cystic component and 30% increase in diffuse component was statistically significant (p value < 0.05). At baseline the OPL+ONL was intact in just 3%, cystic in 57%, diffuse in 7% and mixed in 33% eyes. At 6 months, no eyes showed intact OPL+PNL layer, 20% showed cystic change, 43% showed diffuse and 37% eyes showed mixed results. Thus the change from cystic to diffuse was statistically significant (p value < 0.05). At baseline the ELM was intact in 17%, disrupted in 13%, absent in 20% and mixed in 50% . At 6 months, the ELM was intact in 23% , disrupted in 13%, absent in 13% and mixed in 50% of eyes. At baseline ellipsoid is intact in 23%, disrupted in 7%, absent in 30% and mixed in 40%. At 6 months the ellipsoid layer was intact in 27%, disrupted in 7%, absent in 23% and mixed in 43% eyes.
Conclusions:
The significant morphological feature is the cystic component settling into diffuse macular oedema in GCL + IPL and OPL + ONL layers. The NFL, ELM and Ellipsoid layers did not change in morphological characteristics.
Keywords: 688 retina •
550 imaging/image analysis: clinical