Abstract
Purpose: :
to define new criteria for the diagnosis of lamellar macular hole (LMH) and to increase understanding in LMH pathogenesis by examining fine anatomic features using Spectral-Domain OCT (SD-OCT) and autofluorescence images (AF).
Methods: :
Retrospective analysis of images from 53 eyes with LMH examined with SD-OCT and AF using Heidelberg Spectralis HRA+OCT. LMH were diagnosed based on OCT appearance: irregular foveal contour; break in the inner fovea; intraretinal splitting and intact foveal photoreceptors. OCTs were reviewed to detect an epi-retinal membrane (ERM), retinal layer in which intraretinal split or cysts were present, relation between vitreous and retina. Minimum retinal thickness in the fovea (mRTF) was measured. If ERM was present it was classified as normal (NERM) or dense (DERM) based on description by Witkin et al. Correlations between ERM type and OCT features were studied. AF images were evaluated to find presence of hyperautofluorecence defect at the fovea and were classified in 2 types: confluent (more then 1) and spot (if single).
Results: :
ERM was detected in all 53 eyes: 34 NERM and 19 DERM. Mean mRTF was: NERM=178.5µm; DERM=119.6µm. Difference was statistically significant (Mann-Whitney Test, p<0.0001). Intraretinal splitting was on the outer plexiform layer in all the patients. DERM had a good correlation with intraretinal splitting or presence of cysts at the level of the Inner Nuclear Layer (Kappa: 0.68) and a light correlation with the integrity of the outer Nuclear Layer (Kappa: 0.31). Association is statistically significant for both: split of INL (Fisher P<0.0001); integrity of ONL (Fisher: P=0.02). There was no correlation with presence of a posterior vitreous detachment, nevertheless if vitreous was attached there was a significant association between DERM and vitreous adherent to the posterior pole (Fisher: P=0.03). AF images revealed a defect in all the patients. Significant association was found between DERM and Spot AF (Fisher P<0,0001).
Conclusions: :
ERM was found in all the patients. Many displayed an unusual thickened aspect that may represent posterior hyaloid trapped between ERM and the internal limiting membrane. ERM contraction plays an important role in LMH formation. In the DERM trapped vitreous could eventually shrinks leading to greater contraction forces and deeper foveal defects as shown by less mRTF in these patients. LMH evolution and therapeutic strategies should be evaluated considering the two classes of ERM.
Keywords: macular holes • imaging/image analysis: clinical • vitreoretinal surgery