Imaging, new methods improve macular hole repair, foveoschisis surgery
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Dennis S.C. Lam |
Improved diagnostic imaging and refined surgical methods have maximized outcomes for macular hole repair in recent decades, according to one surgeon. Foveoschisis surgery, albeit with risk of complications of its own, has also shown promising results.
Dennis S.C. Lam, MD, FRCOphth, OSN Asia-Pacific Edition Associate Editor, described recent diagnostic and surgical innovations at the joint meeting of the Asia-Pacific Academy of Ophthalmology and American Academy of Ophthalmology in Nusa Dua, Indonesia.
“The first treatment was reported in 1991 with vitrectomy, and there was reasonable success,” Prof. Lam said. “This opened up a new era for the treatment of these macular holes. Nowadays, surgery is the standard, and the success rate is pretty high.”
More recently, spectral domain optical coherence tomography has enhanced retinal imaging, improving diagnostic accuracy and prognosis prediction.
“With all of these improvements in imaging, we are able to make a firm diagnosis, as well as predict the surgical outcome,” he said. “This is an important development in terms of managing macular holes.”
Surgery is indicated for stage 2, stage 3 and stage 4 macular holes, Prof. Lam said.
“If you wait for too long and wait for stage 3 or stage 4, then usually the surgical outcome is suboptimal,” he said. “So the best timing, or the stage that we’ll be getting optimal outcomes, is stage 2.”
In Hong Kong, combined phacoemulsification and macular hole surgery are a routine practice for many surgeons because of the high incidence of cataract complication that would require a second operation, Prof. Lam said. However, the success of combined phaco and macular hole surgery hinges largely on surgeon experience.
Internal limiting membrane peeling
Improved imaging and instrumentation have encouraged more surgeons to peel the internal limiting membrane, Prof. Lam said. However, the ideal dye for staining the internal limiting membrane is not yet available.
Indocyanine green (ICG) staining enables high-definition imaging, but there are concerns about toxicity in sufficiently high concentrations.
OCT scans of myopic foveoschisis associated
with an epiretinal membrane (left) before and (right) after PPV + ERM + ILM
peelings + gas-fluid exchange. Postoperative scan showed absence of epiretinal
membrane and complete resolution of the foveoschisis.
Images: Lam DSC |
OCT scans of myopic macular hole with macular detachment: (top ) before, (middle) after the first operation (PPV + gas-fluid exchange), and (bottom) after the second operation (ILM peeling + endolaser at the base of the macular hole + gas-fluid exchange). Postoperative scan showed complete closure of the macular hole after the second operation. |
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With advent of OCT technology, diagnosing a
macular hole, preoperative assessment of success rate of the surgery and
postoperative monitoring of hole closure are made much easier. The next phase
of development could be enhanced by the spectral domain OCT that can give a
higher resolution image of the macular hole and its relationship to the
vitreous and its attachment. |
“If you want to use ICG, first of all, you need to think of an alternative,” he said. “Then, if you’re actually using it, take appropriate precautions. Be cautious in terms of using the lowest possible concentration and duration. And avoid … light exposure because of the photochemical reactions that may create toxicity. Then, we want to limit the area of the ICG exposure.”
Alternatives to ICG such as trypan blue offer poorer visualization, Prof. Lam said, adding that the dye brilliant blue may offer better visualization with good safety.
Optimal posturing
OCT has enabled improved postoperative monitoring of macular holes. Recent studies have shown that after the first 2 days postop, further face-down posturing may not be needed at all, Prof. Lam said.
He cited recent studies showing that at only 3 hours postop, a macular hole can be closed, and that most macular holes close after 1 day. One study showed that if the macular hole is not closed at 2 days postop, continuous posturing is unlikely to achieve closure.
“These are new studies,” Prof. Lam said. “All of these are pointing to a direction that if you have macular hole closure in the first 24 to 48 hours, it’s done. If not, even if you continue the posturing, it’s not going to help you. This is a very important development.”
Another study showed that even without posturing, successful hole closure was achieved in 92% of cases.
Surface tension is more critical than the force created by lying face-down. The key is to have a large enough gas bubble that can cover and close the macular hole. “These could be good enough, even without the face-down position,” he said.
Foveoschisis data lacking
Foveoschisis, a complication of high myopia, may cause the formation of macular hole, retinal detachment and retinal nerve damage. Although there are studies showing positive visual outcomes for foveoschisis surgery, larger scale studies are needed to show its safety and efficacy, Prof. Lam said.
“We cannot give you a good prediction of the results because they are only case series,” he said.
OCT is critical for diagnosis of foveoschisis, but apart from visual impairment and presence of epiretinal membrane, indications for surgery are not firmly established.
“You may not be able to get the foveoschisis completely resolved after the surgery,” Prof. Lam said. “You may also create complications. So the indication for surgery, for foveoschisis at the moment, is not too clearly defined.” – by Matt Hasson
Click here for Guide to Vitrectomy Units and Guide to Hand-held Vitrectomy Instruments
- Dennis S.C. Lam, MD, FRCOphth, can be reached at Hong Kong Eye Hospital, The Chinese University of Hong Kong, 3/F, 147K Argyle St., Kowloon, Hong Kong SAR, China; 852-2762-3157; fax: 852-2715-9490; e-mail: dennislam_pub@cuhk.edu.hk.