Approaching high myopia
Dedicated session examined diagnosis and treatment in myopic eyes
Macular buckling represents a safe and effective surgical option for foveoschisis and full-thickness macular holes (FTMH) in highly myopic eyes, said Lin Lu MD, China, speaking during the dedicated myopia session at EURETINA 2020 Virtual, which addressed pathogenesis, diagnosis and treatment of high myopia.
Outlining three-year outcome data on this complicated surgical technique, Dr Lu said macular buckling showed a high closure rate and virtually no tendency to recur. In this approach, visual acuity can be improved and axial length can be preserved for longer.
His study involved 28 patients (28 eyes) with foveoschisis and 21 patients (21 eyes) with FTMH with macular detachment. Retinal reattachment was achieved in all cases, while macular hole closure was achieved in 76.19%. BCVA significantly improved one year postoperatively in the foveoschisis cases and two years in the FTMH cases. The mean axial length decreased by 2.09mm postoperatively.
During this session, Yasushi Ikuno MD, Japan, compared various surgical approaches for myopic macular diseases. Standard techniques include vitreous cortex removal from the retinal surface, epiretinal membrane if present, internal limiting membrane (ILM) peeling and gas/air tamponade, which remains very controversial.
Within foveoschisis, there are three subtypes (retinoschisis, foveal detachment and macular holes), which have different surgical results, varying from being most effective in foveal detachment to limited benefit in macular holes, he explained. Macular holes are a significant risk factor post-surgery, occurring in about 20-to-30% of eyes according the literature, “with IOS/OS in OCT and foveal detachment identified as a high-risk group”.
Dr Ikuno discussed an interesting new FS surgery technique – the foveola non-peeling technique in ILM: “In this technique you peel the ILM in a doughnut fashion and save the ILM as a central part to limit the damage of the foveola.
Unresolved issues in macular hole retinal detachment (MHRD) include low retinal reattachment rates, and macular hole closure rates despite surgical improvements. The inverted ILM flap method is the most promising method for macular hole closure, he stated.
Tzyy-Chang Ho MD, Taiwan, addressed the thinking processes and practices in the management of vitreoretinal interface disorders in pathological myopia, looking at ‘internal’ and ‘external’ surgical approaches. “For the external approach I prefer posterior scleral reinforcement with a pliable Gore-Tex strip to support the staphyloma without protrusion.”
With the internal approach, Prof Ho said the key point is the recovery of microstructures, ie foveola layers (outer nuclear layer/external limiting membrane, ellipsoid zone), adding: “I prefer the foveola non-peeling ILM technique. The ILM margin must not be elevated.”
He discussed his own large series (95 eyes) long-term results of C-shaped temporal inverted ILM flap in macular hole retinal detachment in highly myopic eyes. The fovea was flattened and the macular hole sealed in 93 eyes (97.8%).
“In the two eyes that failed the ILM flap was found to flip back to the temporal side of the flap and the ILM flap was elevated at the margin to cover and seal the hole in the secondary vitrectomy.”
There was retinal detachment with new peripheral break in two eyes in the study, which were reattached after secondary vitrectomy.
The same ILM non-peeling technique can be used for lamellar macular holes with epiretinal proliferation, added Prof Ho, concluding: “I advocate the concept of foveolar reconstruction in the repair of vitreoretinal interface disorders.”
Also addressing this session, Kyoko Ohno-Matsui MD, Japan, said that ultra-widefield swept source OCT produces high-resolution and extended-size tomographic images of various tissues from the vitreous to the sclera. “This technology is a valuable method to identify how vitreous and sclera become pathological and how such pathologies lead to vitreoretinal tractional diseases in synchronicity.”
In another imaging presentation, Xiaoxin Li MD, China, reviewed the use of structural OCT to differentiate between punctate inner choroidopathy (PIC), PIC-choroidal neovascularisation (CNV) and myopic CNV.
The three inflammatory lesions look similar on spectral domain (SD)-OCT but the treatment is different – myopic CNV and PIC-CNV need anti-VEGF treatment while PIC is a self-limited disease that does not, thus accurate diagnosis is essential, she explained.
Prof Li quoted study data looking at the structural characteristics of inflammatory lesions on SD-OCT using OCT-angiography (OCT-A) in myopic (at least -5D) patients with acute blurred/distorted vision, who were followed up for a minimum of two months and had active hyper-reflective lesions on SD-OCT.
The data showed that disruption of retinal pigment epithelium (RPE)/Bruch’s membrane is a definite sign for CNV, while hyper-transmission is a sign for PIC-CNV within four weeks (100%), with hypo transmission together after four weeks.
In addition, hypo transmission was shown to be a sign for myopic CNV, while neither transmission changes or disruption of RPE/ Bruch’s membrane were found in PIC.
Thus this form of imaging provides a convenient, non-invasive strategy for accurate diagnosis and treatment of these lesions, concluded Prof Li.