2 The procedure
2.1.1 AMD is the most common cause of blindness in developed countries. A small proportion of patients with AMD have wet AMD. Wet AMD is characterised by the abnormal growth of blood vessels in the choroid layer underneath the macular part of the retina. These vessels can threaten vision if they leak and cause scarring.
2.1.2 Current treatments for wet AMD include laser photocoagulation, photodynamic therapy (PDT), intravitreal injections of antivascular endothelial growth factor agents and implantation of miniature lens systems. Patients with advanced disease may benefit from optical aids such as magnifying glasses.
2.2.1 The aim of this procedure is to move the macula so that it lies over a healthier part of the choroid layer that is unaffected by neovascularisation.
2.2.2 In macular translocation with 360° retinotomy for wet AMD, a vitrectomy is done and the retina is then detached from the back of the eye using an injection of saline solution. An incision is made around the entire perimeter of the retina so that it is freely mobile, and attached only at the optic disc. The abnormal choroidal vessels are removed and the retina is reattached with the macula rotated away from the original disease site. Once the retina is reattached the vitreous cavity is injected with silicone oil for tamponade. In a second operation approximately 1–2 months later, the whole globe is rotated in the opposite direction by dividing and reattaching the external ocular muscles in order to remove the resulting visual disturbance caused by the torsion, and the silicone oil is drained from the vitreous cavity.
Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview.
2.3.1 A randomised controlled trial (RCT) of 50 patients treated by the procedure or PDT reported an increase of 3 lines or more of best corrected visual acuity (BCVA) in 28% (7/25) and 0% (0/25) of patients respectively at 24-month follow-up (p < 0.01). A case series of 50 patients reported 2-line or greater BCVA improvement in 66% (33/50), no improvement in 28% (14/50) and a loss of more than 2 lines in 6% (3/50) of patients at 21-month follow-up. A case series of 64 patients reported BCVA improvement of 1 line or more in 52% (32/61) and a loss of more than 3 lines in 11% (7/61) of patients at 12-month follow-up.
2.3.2 A non-randomised controlled study of 24 patients reported that mean BCVA improved from 0.90 to 0.69 logMAR in 12 patients treated by the procedure (p = 0.09) and worsened from 0.87 to 1.38 logMAR in 12 patients treated by choroidal patch graft at 3-year follow-up (p < 0.001).
2.3.3 The case series of 64 patients reported that median reading speed improved among 55 patients from 71 words per minute at baseline to 105 words per minute at 12-month follow-up (p < 0.001).
2.3.4 The RCT of 50 patients reported no difference in quality-of-life scores between patients treated by the procedure or PDT for general vision (p = 0.27) at 24-month follow-up.
2.3.5 The Specialist Advisers listed key efficacy outcomes as attached retina following surgery, functional outcomes of BCVA, and reading speed.
2.4.1 Retinal detachment (requiring vitrectomy and endotamponade for reattachment) was reported in 24% (6/25) of patients treated by the procedure in the RCT of 50 patients. In case series of 90 and 64 patients, retinal detachment was reported in 19% (absolute figures not stated) and 8% (5/61) of patients respectively (12-month follow-up for both studies).
2.4.2 In the non-randomised controlled study of 24 patients, residual torsion requiring a third procedure was reported in 17% (2/12) of patients treated by the procedure (timing of events not stated).
2.4.3 Retinal slippage from the desired final location after translocation was reported in 3% (2/75) of eyes in the case series of 75 eyes (number of patients not stated).
2.4.4 The Specialist Advisers stated that adverse events reported in the literature include proliferative vitreoretinopathy, macular oedema, diplopia and phthisis. They listed theoretical adverse events as recurrence of neovascularisation.
2.5.1 The Committee noted that intravitreal injections of antivascular endothelial growth factor agents are more commonly used for the treatment of AMD than surgical techniques. For more information see 'Ranibizumab and pegaptanib for the treatment of age-related macular degeneration' (NICE technology appraisal guidance 155).