Highly myopic macular holes
Newer techniques lead to better outcomes in myopic macular holes
Recent advances in diagnostic instruments and vitreoretinal surgical techniques have led to improved anatomical and visual outcomes for patients with various macular pathologies associated with high myopia such as maculoschisis and macular holes, according to José García-Arumí MD, PhD.
“We have made a lot of progress in the surgical treatment of these patients over recent years. Small-gauge surgery with internal limiting membrane (ILM) foveal-sparing dissection and gas tamponade is a good option for symptomatic myopic foveoschisis, with inverted flap dissection technique increasing the rate of macular hole closure and visual acuity improvement,” he told delegates attending the 19th EURETINA Congress in Paris, France.
In a broad overview of the natural history, surgical indications and expected outcomes of myopic maculoschisis and macular holes, Prof García-Arumí, Instituto de Microcirugía Ocular, Barcelona, Spain, explained that there is an incidence of between 8 and 34% of maculoschisis in eyes with high myopia.
“It is a slowly progressive condition, combined sometimes with foveal detachment, lamellar or full-thickness macular hole, epiretinal membrane or vitreomacular traction. We know that 50% of these patients will develop macular hole or macular hole retinal detachment (MHRD), which can cause severe visual impairment and greatly impact on their quality of life,” he said.
Surgery is indicated if there is a decrease of visual acuity or foveal detachment.
“We need to bear in mind that foveal detachment is a risk factor for postoperative macular hole and worse postoperative visual acuity,” said Prof García-Arumí.
SPARING THE FOVEA
The recommended surgical approach for such cases is vitrectomy with posterior hyaloid dissection, foveal sparing ILM peeling and gas tamponade.
“We know from studies that there is a greater incidence of macular holes with complete ILM peeling compared to a foveal-sparing ILM peeling technique. Postoperative visual acuity is also better in patients treated with the foveal-sparing technique,” he said.
Similarly, the studies in the scientific literature show that gas tamponade resulted in a higher resolution of foveoschisis in a shorter period of time than patients treated without gas, he added.
Prof García-Arumí noted that myopic macular hole is associated with posterior staphyloma in eyes with over 10D of myopia.
“There is not a detached posterior hyaloid in some cases because of vitreoschisis, and the diagnosis is frequently difficult due to RPE and choroidal atrophy. We see an evolution of myopic retinoschisis in 25% of patients. Asymptomatic macular hole is more prevalent in eyes with higher degrees of myopia and pronounced posterior staphyloma. Myopic macular holes may also be associated with a rhegmatogenous retinal detachment surrounding the hole,” he said.
Surgery is usually advocated in myopic macular holes, said Prof García-Arumí, “because we can improve the visual acuity and decrease the risk of retinal detachment”.
Nevertheless, the closure rates of myopic macular holes are reduced with the presence of posterior staphyloma and foveoschisis or in axial lengths of over 30mm, he said.
The anatomic success rate of myopic macular hole closure has improved in recent years with the introduction of the inverted ILM flap technique first described by Michalewska et al in 2010. In this approach, the ILM is not completely removed from the retina but is left in place, attached to the edges of the macular hole. This ILM remnant is then inverted to cover and fill the macular hole before fluid-air exchange is performed.
The superior results with the inverted ILM flap technique have been borne out by numerous studies in the scientific literature, said Prof García-Arumí.
“In our own series of patients in 2018, the rate of closure was 92% in the inverted flap group and 81% in the standard ILM group, but the differences are much greater in the other studies that have compared the two techniques,” he said.
GOOD STAINING ESSENTIAL
One of the pearls for smooth surgery in these patients is to always stain the ILM properly, said Prof García-Arumí.
“Staining is critical because the ILM is very thin in these patients, and the RPE does not give a good contrast to really assess the quality of the ILM and perform the dissection around the macular hole,” he said.
Retinal detachment in myopic macular holes is more likely in highly myopic eyes with posterior staphyloma, and tangential traction from the vitreous cortex. There is also a higher risk of detachment if the macular hole is associated with foveoschisis, he said.
While there is no standard treatment for retinal detachment due to macular hole, Prof García-Arumí said his own preferred approach is vitrectomy with gas, silicone oil, ILM dissection and inverted flap technique with adjunctive buckling.
“The overall success rate is poorer than conventional retinal detachment, but it is interesting to note that Wakabayashi et al in 2018 had a 92% anatomic reattachment and closure rate with inverted flap technique compared with 39% for standard ILM peeling,” he said.
While macular buckling can be indicated when vitrectomy and inverted flap fails, the high risk of complications means that it is less frequently employed, he concluded.
José García-Arumí: firstname.lastname@example.org