April 2007, Vol. 36 No. 4 293 ILMP for Macular Oedema—Xiao-Ling Liang et al Pars Plana Vitrectomy and Internal Limiting Membrane Peeling for Macular Oedema Secondary to Retinal Vein Occlusion: a Pilot Study Xiao-Ling Liang, 1* MD, PhD, Hao-Yu Chen, 1* MD, Yong-Sheng Huang, 1 MD, Kah-Guan Au Eong, 2-5 MMed (Ophth), FRCS, Shan-Shan Yu, 1 BS, Xing Liu, 1 MD, PhD, Hong Yan, 1 MD Introduction Macular oedema is a major cause of visual impairment in a number of ocular conditions such as diabetic retinopathy, retinal vein occlusion, Irvine-Gass syndrome and uveitis. 1 In one study, cystoid macular oedema contributed to 37.9% of low vision in patients with retinal vein occlusion. 2 Persistent macular oedema may lead to the irreversible loss of photoreceptors and vision. 3 The pathogenesis of macular oedema is diverse. Breakdown of the blood-retinal barrier and traction at the vitreomacular interface have been suggested to be important factors in several studies. 4-9 The treatment of macular oedema remains difficult and controversial. Carbonic anhydrase inhibitors are limited by systemic complications such as disturbance of the water- electrolyte balance. 10 Non-steroidal anti-inflammatory drugs (NSAIDS) fail to reduce macular oedema caused by retinal vascular disorders. 11 Although intravitreal injection of corticosteroid may reduce diabetic macular oedema and improve visual acuity, its use is associated with complications such as glaucoma, endophthalmitis and recurrence of the macular oedema. 12 Laser photocoagulation has been shown to be of little benefit in improving visual acuity in cystoid macular oedema. 13 Several studies have demonstrated the regression of macular oedema and improvement in visual acuity after pars plana vitrectomy for diabetic retinopathy, retinal vein 1 State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China 2 The Eye Institute at Alexandra Hospital, National Healthcare Group, Singapore 3 Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 4 The Eye Institute at Tan Tock Seng Hospital, National Healthcare Group, Singapore 5 Singapore Eye Research Institute, Singapore Address for Correspondence: Dr Xiao-Ling Liang, 54 S. Xianlie Road, Guangzhou 510060, People’s Republic of China. Email: Liangxlsums@yahoo.com.cn *Drs Liang and Chen contributed equally to this study and should be considered equivalent first authors. Abstract Introduction: Macular oedema is the main cause of visual impairment following retinal vein occlusion. The purpose of this study was to evaluate the anatomical and functional outcome of pars plana vitrectomy and internal limited membrane (ILM) peeling for macular oedema secondary to retinal vein occlusion. Clinical Picture: This pilot study is a prospective non- randomised series of 11 eyes of 11 patients with macular oedema secondary to retinal vein occlusion. The best-corrected visual acuity (BCVA), foveal thickness on optical coherence tomography, fundus fluorescein angiography (FFA) and multifocal electroretinography were evaluated. Treatment and Outcome: All 11 patients underwent pars plana vitrectomy with ILM peeling. The mean postoperative follow-up was 13.5 months (range, 1.5 to 24). The mean thickness at the foveal centre decreased from 794 ± 276 μm preoperatively to 373 ± 150 μm, 302 ± 119 μm, 249 ± 203 μm and 185 ± 66 μm at 1 week, 1 month, 3 months and the final visit postoperatively, respectively (all P <0.001, paired t- test, compared to preoperative thickness). Postoperative FFA demonstrated markedly reduced leakage in the macular region. At the final visit, BCVA improved 2 lines or more in 72.7% (8/11) of patients and was unchanged in 27.3% (3/11) patients. Complications included cataract in 7 patients and vitreous haemorrhage, recurrence of macular oedema and visual field defect in 1 case each. Conclusion: Pars plana vitrectomy and ILM peeling rapidly reduced the macular oedema caused by retinal vein occlusion, with improvement in BCVA. Ann Acad Med Singapore 2007;36:293-7 Key words: Foveal thickness, Internal limiting membrane peeling, Macular oedema, Retinal vein occlusion, Visual acuity Case Series