Wong, D

British Journal of Ophthalmology

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Title To peel or not to peel the internal limiting membrane: A questionfinally answered?Author(s) Wong, DCitation British Journal Of Ophthalmology, 2009, v. 93 n. 8, p. 987-988Issued Date 2009URL http://hdl.handle.net/10722/60894Rights British Journal of Ophthalmology: a question finally answered?.Copyright © BMJ Publishing Group.To peel or not to peel the internallimiting membrane: a questionfinally answered?David WongFor the surgical treatment of idiopathicthickness macular hole, the question ofwhether to peel or not to peel the internallimiting membrane (ILM) has been askedrepeatedly since at least 2002.1 2 Mostsurgeons carry out ILM peeling routinely.Many are already convinced of its benefit.Is it worthwhile conducting a randomisedtrial when the clinical practice of ILM peelhas already been widely adopted? Is theanswer simply academic?If all macular holes respond in the sameway to surgery, the answer might indeedbe academic. They do not. It is now clearthat smaller holes close more readily.3 Alesser intervention may be appropriate forthe treatment of smaller holes. For exam-ple, a recent randomised trial comparing afacedown versus a seated position foundthat the success rate in idiopathic macularholes smaller than 400 mm was notinfluenced by postoperative posture.4On the other hand, if the maximumintervention works best, why not apply itto every patient? After all, there is a priceto pay for failure in primary closure. Holesthat do not close after the first vitrectomytend to increase in size, and even whenthey are closed with a repeat operation,the visual results are often poor.5 Thepoint is that the maximum algorithm hasits drawbacks. The use of long-actinggases and head-down posture may simplybe inconvenient for patients. ILM peelingand preretinal manipulations may impor-tantly be associated with retinal pigmentepithelial changes,6 trauma to the neuro-sensory retina, phototoxicity resultingfrom prolonged manipulations and possi-ble adverse reactions to the dyes used.7In this issue (see page 1005),Christensen carried out a randomised con-trolled trial of no peel versus peel usingIndocyanine Green (ICG) in a single centre,Glostrup Hospital in Denmark.8 This well-conducted study aimed at examining thevalue of ILM peeling in stage-2 and -3idiopathic macular hole surgery. Theresults show that surgery with ILM peel-ing, for both stage 2 and -3 macular hole, isassociated with a significantly higher clo-sure rate than surgery without ILM peeling(stage 2: 100% vs 55%; stage 3: 90% vs36%). The results seem convincing.Does this mean that the question isnow finally answered? Yes and no. Theremay still be room for doubt, given thatrandomisation was changed after 40patients were recruited. The interimanalysis of stage 3 holes showed that thepeeled group did significantly better. Thestopping rule for randomisation meantthat it was unethical to continue. For theremainder of the trial, the patients withstage 3 holes were randomised 2:1 to ILMpeeling with Trypan Blue (TB) or ICG.The randomisation to no peeling stoppedafter 14 stage 3 holes were recruited(presumably because nine holes failed to,as the anatomical success rate in thisgroup was 36%). Is this a representativeresult, or is it a statistical quirk due toclustering of failures? Brooks, in a non-randomised study, achieved with no ILMpeeling an anatomical success rate of82%;9 Margherio et al, in a consecutivestudy, achieved with no ILM peeling ananatomical closure rate of 86%.10The majority of the patients (.80%) inthis Danish trial were rendered pseudo-phakic 4 weeks prior to the vitrectomy.This was done in order to eliminate one ofthe major confounding factors thatdogged many previous studies on macularhole surgery, namely progressive lensopacity following vitrectomy affectingthe visual outcome. However, could thecataract surgery have contributed to theunusually low anatomical success rate ofnon-peeling group? A recent study onpatients who had cataract surgery before,after or combined with vitrectomy andvitrectomy alone for idiopathic macularhole found that cystoid macular oedemawas associated with a sevenfold increasein reopening of the closed macular holes.11There is a high incidence of cystoidmacular oedema following cataract sur-gery, the majority being subclinical.12Equally, ILM peeling is a recognisedtreatment for cystoid macular oedema inconditions such as diabetic retinopathyand retinal vein occlusion.13 14 Is it con-ceivable that by rendering the patientspseudophakic prior to the vitrectomy, thetrial favoured ILM peeling and disadvan-taged the no-peeling group?What started off as a study to addressprimarily a single research question,namely, ‘‘Is peeling better than no peel-ing?’’, effectively became a three-arm trialof no dye (and no peel) versus ICG-assisted peeling versus TB-assisted peel-ing. Nonetheless, the information yieldedby the second randomisation is bothinteresting and relevant. The study con-cluded that ‘‘intraoperative ILM stainingwith 0.05% isotonic ICG was not asso-ciated with a significantly different visualoutcome than non-peeling or TB peelingin eyes with primary hole closure.’’ One ofthe many strengths of this study was therecording of postoperative visual fields inall patients. A visual-field defect occurredin one of 35 patients treated with ICG,one of 18 patients with TB and none withnon-peeling. Those surgeons who use ICGroutinely might take comfort from theresults of this trial and conclude that ICGat a concentration of 0.05% is safe.Equally, those who have experiencedunexplained visual-field loss followingICG-assisted peel might believe that theadverse reaction to this dye is idiosyn-cratic and as such not likely to be detectedin a relatively small number of patients.There is still variation in our approachesto the treatment of idiopathic macularhole. There are those surgeons who do nopeeling, those who peel but use no dye,those who use ICG-assisted peel and yetothers who are switching to the newer andpurported ‘‘safer’’ dyes.15 It is fair to saythat the majority are already persuaded bythe efficacy of ILM peeling, andChristensen et al through their meticulousstudy will convince even more surgeons topeel routinely. It is noteworthy that theonly other randomised trial of vitrectomywith or without ILM peeling of foridiopathic macular hole in Chinese patientsfound a very similar anatomical closure rateof 92% and 32% respectively.16 There is aUK multicentre randomised trial of ILMpeel versus no peel that has finishedrecruiting.17 (FILMS is registered withCurrent Controlled Trials ISRCTN num-ber 33175422 and Clinical Trials.gov iden-tifier NCT00286507.) It would beinteresting to see if the British resultscorroborated that of the Danish trial.Competing interests: None.Correspondence to: Dr David Wong, St Paul’s Eye Unit,Royal Liverpool University Hospital, Prescot Street,Liverpool L7 8XP, UK; shdwong@liv.ac.ukEditorialBr J Ophthalmol August 2009 Vol 93 No 8 987 group.bmj.com on December 15, 2011 - Published by bjo.bmj.comDownloaded from Br J Ophthalmol 2009;93:987–988.doi:10.1136/bjo.2008.156521REFERENCES1. Kuhn F. Point: to peel or not to peel, that is thequestion. Ophthalmology 2002;109:9–11.2. Hassan T, Williams GA. Counterpoint: to peel or notto peel: is that the question? Ophthalmology2002;109:11–12.3. Tadayoni R, Gaudric A, Haouchine B, et al.Relationship between macular hole size and thepotential benefit of internal limiting membranepeeling. Br J Ophthalmol 2006;90:1239–41.4. Guillaubey A, Malvitte L, Lafontaine PO, et al.Comparison of face-down and seated position afteridiopathic macular hole surgery: a randomized clinicaltrial. Am J Ophthalmol 2008;146:128–34.5. Valldeperas X, Wong D. Is it worth reoperating onmacular holes? Ophthalmology 2008;115:158–63.6. Poliner LS, Tornambe PE. Retinal pigmentepitheliopathy after macular hole surgery.Ophthalmology 1992;99:1671–7.7. Engelbrecht NE, Freeman J, Sternberg P Jr, et al.Retinal pigment epithelial changes after macular holesurgery with indocyanine green-assisted internallimiting membrane peeling. Am J Ophthalmol2002;133:89–94.8. Christensen UC, Krøyer K, Sander B, et al. Value ofinternal limiting membrane peeling in surgery foridiopathic macular hole stage 2 and 3—a randomizedclinical trial. Br J Ophthalmol 2009;93:1005–1015.9. Brooks HL Jr. Macular hole surgery with andwithout internal limiting membrane peeling.Ophthalmology 2000;107:1939–48.10. Margherio RR, Margherio AR, Williams GA, et al.Effect of perifoveal tissue dissection in themanagement of acute idiopathic full-thicknessmacular holes. Arch Ophthalmol 2000;118:495–8.11. Bhatnagar P, Kaiser PK, Smith SD, et al. Reopeningof previously closed macular holes after cataractextraction. Am J Ophthalmol 2007;144:252–9.12. Ching HY, Wong AC, Wong CC, et al. Cystoidmacular oedema and changes in retinal thicknessafter phacoemulsification with optical coherencetomography. Eye 2006;20:297–303.13. Patel JI, Hykin PG, Schadt M, et al. Pars planavitrectomy with and without peeling of the innerlimiting membrane for diabetic macular edema. Retina2006;26:5–13.14. Mandelcorn MS, Nrusimhadevara RK. Internallimiting membrane peeling for decompression ofmacular edema in retinal vein occlusion: a report of 14cases. Retina 2004;24:348–55.15. Remy M, Thaler S, Schumann RG, et al. An in vivoevaluation of Brilliant Blue G in animals and humans.Br J Ophthalmol 2008;92:1142–7.16. Kwok AK, Lai TY, Wong VW. Idiopathic macularhole surgery in Chinese patients: a randomisedstudy to compare indocyanine green-assistedinternal limiting membrane peeling with no internallimiting membrane peeling. Hong Kong Med J2005;11:259–66.17. Lois N, Burr J, Norrie J, et al. Clinical and cost-effectiveness of internal limiting membrane peeling forpatients with idiopathic full thickness macular hole.Protocol for a Randomised Controlled Trial: FILMS(Full-thickness macular hole and Internal LimitingMembrane peeling Study). Trials 2008;3:61.Editorial988 Br J Ophthalmol August 2009 Vol 93 No 8 group.bmj.com on December 15, 2011 - Published by bjo.bmj.comDownloaded from 

To peel or not to peel the internal limiting membrane: A question finally answered?

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To peel or not to peel the internal limiting membrane: A question finally answered?

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