We read with interest Dr Wong’s article entitled “Longitudinal study of macular folds by spectral-domain optical coherence tomography.” In this study 10 patients operated on for rhegmatogenous retinal detachment (RD) and showing retinal folds postoperatively are prospectively followed. On the basis of color fundus photography and optical coherence tomography (OCT), 3 patterns of macular folds are identified: “ripple” (7 patients), “taco” (2 patients), and “displacement” (1 patient) folds.
There are some aspects of the study on which we would like to comment.
Dr Wong does not provide information regarding the scheduled follow-up visits and the OCT protocol used to record the images. These are important aspects because they can affect the interpretation of the clinical data and OCT findings, making the conclusions weak or unreliable.
According to the author description, ripple and taco folds share several characteristics, the ripple essentially differing from the taco by the larger size on OCT and by a white line running along the fold discernible on ophthalmoscopy. However, it has been recently shown that, depending on OCT sections (transverse, axial, or oblique to the main axis of the fold), the scanned folds may appear variable both in shape (round, mushroom-like, trampoline-like) and in size. Ideally, only transverse scans (perpendicular to the main axis of the folds) should be considered when making comparisons.
Furthermore, our experience is that on careful funduscopic examination, subtle retinal folds (corresponding to ripple folds on OCT) also appear as white-yellow lines.
Both ripple and taco folds tend to resolve spontaneously over time. It is possible that some ripple folds scanned a few months after operation were taco in the immediate postoperative period. Considering that ripple and taco folds are not associated with peculiar symptoms or different pathogenesis, distinguishing between the two could be unnecessary.
The third recognized pattern, observed in only 1 patient complaining of postoperative binocular diplopia, is named “displacement fold.” The term displacement fold does not appear appropriate for 2 reasons. First, unintentional displacement of the retina may be involved in ripple and taco fold formation as well. In fact, it is not the fold that causes the displacement but the displacement that causes the fold. Second, the translocation may persist despite the resolution of the fold.
Unintentional retinal translocation occurring after RD repair is elegantly visualized using fundus autofluorescence (FAF). Concomitant presence of retinal translocation and small partial-thickness retinal folds, using simultaneous OCT-FAF imaging, has been described. Dr Wong did not record FAF, so it cannot be excluded that even the cases showing ripple or taco folds in his series presented with associated retinal translocation.
The author proposes that in case of a displacement fold, redetachment of the retina or extraocular muscle surgery may be advisable. In our opinion, the degree of translocation and of the resulting binocular diplopia (not evaluable either with funduscopy or with OCT), instead of the mere presence of a fold (not showing any pathognomonic feature and potentially resolving without treatment), should be regarded as an indication for further surgery.