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Retinal folds are a relatively uncommon complication of retinal surgery. Macula involvement can produce poor acuity and disturbing metamorphopsia. We report a novel treatment for macula fold using the surgical techniques of foveal translocation and perfluorohexyloctane (F6H8), a new heavier than water agent licensed for long term internal tamponade.1,2
A 51 year old man with Terson’s syndrome was found to have retinal detachment on B-scan ultrasonography. He underwent vitrectomy and lensectomy with C2F6 gas tamponade for a superior, macula off retinal detachment. He was postured face down overnight. A retinal fold crossing the macula was noted on the first postoperative day (Fig 1A). At 3 months the best corrected acuity was 6/24. The patient described the image in the affected eye as being split diagonally, with the two half images separated. He was referred to our unit for further management.
We used a 41 gauge needle to detach approximately one quarter of the retina by saline infusion into the subretinal space.3 F6H8 was injected displacing subretinal fluid (SRF) anteriorly, opening out the retinal fold and reapposing the photoreceptors to the pigment epithelium. No direct retinal manipulation was required. The SRF was left in situ and the patient postured on his back to allow the retina to “iron out” slowly as the SRF resorbed. The F6H8 was removed after 5 days. The retina remained flat, without folds (Fig 1B). Seven weeks after surgery his metamorphopsia had resolved with a best corrected acuity of 6/18+2.
Electroretinography was performed before and 10 weeks after surgery using ISCEV standard protocol. The ERG responses showed no evidence of diminution following redetachment and subsequent removal of F6H8 tamponade. (Standard flash in dark adapted state gave a-wave amplitudes of 195 μV before surgery and 219 μV after; b-wave amplitudes of 367 μV before and 453 μV after.)
Retinal folds through the macula have been reported following both vitrectomy4 and conventional surgery for retinal detachment.5 Van Meurs et al report the incidence as 2.8% with conventional surgery.6 Risk factors for retinal folds include superior bullous detachment, gas tamponade (bubble large in relation to detachment), circumferential buckles, and incomplete drainage of SRF. When gas tamponade is used in the presence of residual SRF starting the posturing with the break dependent and slowly rolling the patient to the desired posture may reduce the risk of macula folds. Larrison et al4 reported that out of 15 cases with folds involving the macula one third had postoperative acuity of 6/60 or worse and only one third managed 6/18 or better (mean follow up 25 months). Recent data from a dog model of macula relocation7 suggest that macula folds may be associated with progressive visual deterioration. Hayashi et al demonstrated progressive loss of photoreceptors and thinning of the outer nuclear layer within retinal folds. TUNEL assay showed apoptotic cells in the outer and inner nuclear layers of the folds.
Perfluorohexyloctane is a semi-fluorinated alkane with a specific gravity of 1.35, and a high interfacial tension to water (49 mN/m). Its use in complicated retinal detachment surgery and the histology of associated epiretinal membranes have been reported.2 8
We have previously demonstrated that the retina can be stretched by brushing, a phenomenon we referred to as redistribution of neurosensory retina.3 Macular translocation can be achieved without sclera imbrication to generate redundancy,9 by introducing a gas bubble in the presence of a bullous retinal detachment. The bubble occupies the top half of the vitreous cavity. The SRF is displaced inferiorly and, confined by the anterior attachment of retina, puts the macula on stretch.
Similarly, in our patient, we induced a bullous retinal detachment, used a bubble of heavy liquid and postured the patient supine. The F6H8 occupied the dependent part of the vitreous cavity and displaced the SRF peripherally and anteriorly. The SRF is confined by the attachment of the retina at the ora serrata. This effectively put the retina on stretch and “ironed out” the macular fold (Fig 2).
Kertes and Peyman10 reported treatment of retinal folds in two patients having surgery for tractional retinal detachment (one diabetic, one toxocara granuloma). They used peroperative perfluoro-perhydrophenanthrene tamponade and direct retinal manipulation with a silicone tipped cannula. No significant visual improvement was noted as the folds were outside the macula. Our technique involves no direct instrumental manipulation of the central retina. We have been able to effectively treat the macula fold by exploiting the specific gravity of the tamponade agent. Avoidance of macula folds by addressing causative factors is obviously preferable to treatment. We have been impressed with the complete disappearance of the fold in this case. In selected cases surgery may be appropriate to alleviate troublesome metamorphopsia and possibly reduce the risk of permanent and progressive reduction in vision resulting from the macular fold.