We appreciate the comments of Theodossiadis and associates on our article regarding the use of inverted internal limiting membrane (ILM) insertion technique to treat macular hole (MH)-associated retinal detachment in high myopia. In the article, we emphasized the importance of inserting ILM tissue of sufficient size to act as a bridge to facilitate hole closure. The technique could be used regardless of the size of the hole. In fact, the larger the hole was, the easier the secure insertion might be. For a small hole, less ILM tissue or, better, less than the full circle of ILM tissue may suffice. We did not specifically measure the hole size because in such cases, the precise MH size was difficult to determine. The contour of the detached retina and the globe, and the presence of contracted premacular cortical vitreous are some of the factors affecting the accurate MH size measurement. We agree with Theodossiadis and associates that the preexisting small macular hole might be enlarged after the insertion of the ILM. But this tissue stretch and temporary MH enlargement would not jeopardize the hole closure as long as the inverted ILM flap had been securely inserted.
The development of MH in highly myopic eyes can be complex. It may be similar to an idiopathic condition; an MH may come from macular schisis with or without macular detachment, or be associated with macular atrophy with underlying or adjacent submacular scar. An MH developed from schisis was more likely to develop retinal detachment or an enlargement of the pre-existing detachment. After detachment occurs, the schisis may decrease in size or even disappears. In our series, only less than one third of cases had obvious foveoschisis observed by optical coherence tomography preoperatively. We applied the same technique in eyes with or without foveoschisis and the results showed that MHs were closed in all cases with disappearance of schisis.
Subretinal fluid (SRF) after operation has not been a major issue with our technique. The residual SRF either reabsorbed within a few days or gradually decreased in amount until complete reabsorption. Though in highly myopic eyes, Bruch membrane rupture and diffuse patchy chorioretinal atrophy are frequently present, there is still no direct histologic evidence showing a total absence of retinal pigment epithelium (RPE) and thus the total lack of pumping function in the macular area. In addition, the SRF could be effectively displaced by the gas to the more peripheral area where RPE is healthier.
A few factors might contribute to the significant improvement of visual acuity with our technique. Reattachment of the retina itself could help visual improvement. The inserted tissue mainly served as a scaffold to bridge the glial cells and brought the foveal tissue closer, allowing partial regeneration of the outer segment of photoreceptors. The tissue inserted for MH closure can even be nonretinal tissue. Whether the visual function outcome would be better in the long run with the external approach, such as macular buckling, requires further large-scale studies with long follow-up.