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Limited macular translocation (LMT) is one of the treatment options for subfoveal choroidal neovascularisation (CNV) resulting from pathological myopia.1 The fundamental surgical principle involves the transposition of the foveal neurosensory retina to a new site with more healthy underlying retinal pigment epithelium.1,2 Direct laser photocoagulation is usually employed as an adjunct measure in eradicating the original CNV after the surgery. It has been observed that geometrically sizeable translocation is a prerequisite for a long term surgical success.2,3 The degree of translocation is, however, not often predictable and any ineffective displacement may render the subsequent laser photocoagulation extremely difficult or even impossible to perform.2,4 As a result, the recurrent or persistent CNV intruding the newly relocated fovea may jeopardise the final visual outcomes.4,5 Photodynamic therapy (PDT) may be considered a viable adjunct treatment option in such circumstance.
A 41 year old woman with pathological myopia of −11.0 dioptres in both eyes presented with a subfoveal CNV and subretinal haemorrhage in her right eye in July 2000. The best corrected visual acuity (BCVA) was 5/200 in her right eye and 20/30 in her left eye. LMT with superotemporal 6 mm scleral imbrication was performed in July 2000. The operation was uneventful and an inferior displacement of the fovea by 600 μm was achieved. The CNV, however, was still located in the vicinity of the juxtafoveal area and therefore laser photocoagulation, bearing the potential risk of late creeping scar, was not suggested. At the 4 months postoperative visit, her left BCVA was 20/200 and the original CNV became more fibrotic with minimal leakage upon fluorescein angiogram. Nevertheless, she came back at 5 months with a return of metamorphosia and a drop in her right vision from 20/200 to 10/200. Dilated fundus examination showed a tiny patch of submacular haemorrhage in direct continuity with the old fibrotic scar (Fig 1A). Fluorescein angiogram of the early phase demonstrated a fresh recurrent CNV budding out from the original fibrotic CNV and extending to the centre of the foveolar avascular zone (Fig 1B). Moderate fluorescein leakage could be seen in the late phase (Fig 1C). Treatments comprising revision macular translocation surgery, submacular surgery, photodynamic therapy, and observation had been thoroughly discussed with the patient. In view of minimal invasiveness and comparatively better preservation of surrounding neurosensory retinal tissue, PDT was adopted in treating the CNV recurrence. PDT with verteporfin infusion and laser delivery was performed in accordance with the standard protocol.6 After the treatment, the blood clot in the fovea was gradually reabsorbed and the vision improved to 20/200 at 3 months of follow up. Complete regression of the recurrent CNV at the fovea without angiographic leakage was documented over the follow up angiogram at 3 months and subsequently (Fig 1D). The vision remained stable at 20/200 in the latest visit at 24 months after the PDT.
It has been shown that significant visual improvement may be achieved by LMT for the treatment of subfoveal CNV associated with age related macular degeneration (AMD) or pathological myopia.1–5 However, the surgical techniques are demanding and the potential complications are not unusual. One of the late postoperative visually important complications is recurrence of the CNV and this is partially caused by an ineffective translocation of the fovea or a large lesion size of CNV.4,5 The incidence of persistent or recurrent CNV after limited LMT has been reported to be 40% and 35% respectively in age related macular translocation and being 21% and 14% respectively in pathological myopia.4,5 Not many treatment options are available once the fovea is involved. Viable surgical options including repeated LMT, full 360 degree retinotomy MT, or submacular surgery may be considered but the surgical risk may be inadvertently higher in the redetachment of the neurosensory retina. PDT induces a selective thrombosis of the abnormal CNV and has been proved to be an effective treatment in preventing a significant loss of vision in patients with CNV secondary to AMD or pathological myopia.6 Its clinical indications and applications are expanding.7 Its minimal invasiveness and clinical efficacy make it a safer and visually desirable supplementary treatment in recurrent CNV after LMT. In our patient, the complete closure of CNV was achieved with concomitant vision improvement after a single session of PDT without evidence of recurrence at 24 months.
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