Reena M Choudhry 1 , Arun Narayanaswamy 1,2 Bleb Necrosis Following Collagen Matrix Implant Modulated Trabeculectomy Reena M Choudhry 1 , Arun Narayanaswamy 1,2 1 ICARE Eye Hospital and Post-Graduate Institute, NCR, India ; 2 Singapore Eye Research Institute, Singapore Introduction Ologen collagen matrix implant (ProTop & MediKing, Taipei, Taiwan)is a porcine-derived, biodegradable collagen matrix composed of a three-dimensional porous structure of collagen-glycosaminoglycan co-polymers Prevent excessive scarring after trabeculectomy by Guiding the fibroblasts to grow through the matrix pores in a random and diffuse fashion rather than in an organized way Re-modeling in the trabeculectomy wound and reducing scar formation Controlled wound modulation, without inducing tissue destruction and hypocellularity, may result in a lower incidence of bleb-related complications such as leaks, hypotony and infection Collagen matrix implant (Ologen) modulated trabeculectomy has been proposed as an alternative with potential to reduce the incidence of vision threatening complications associated with antimetabolites such as MMC and 5 -FU Literature and short-term data does support a lower incidence of these complications with collagen matrix modulated trabeculectomy We report a rare case of non-infective bleb necrosis following Ologen modulated trabeculectomy Purpose To report a rare case of bleb necrosis at 12 weeks after an uneventful Collagen matrix implant (Ologen TM) modulated trabeculectomy Case report A 45-year-old female presented with BCVA of 6/6 in her right eye and 6/9 in the left. Her presenting intraocular pressures were 28 and 36 mm Hg respectively Grade 1 nuclear sclerotic changes were noted in both eyes Gonioscopy revealed evidence of 1 quadrant synechial closure in the right eye and extensive synechial closure in the left eye Vertical cup:disc ratio of 0.7:1 and 0.9 : 1 was noted in the right and left eyes respectively Advanced field loss was documented in the left eye. At 4 weeks after iridotomy, her intra-ocular pressures normalized in the right eye and was 28 mm Hg despite maximal medical therapy in the left eye The left eye was subjected to a combined phaco-trabeculectomy with collagen matrix implant A fornix based flap was used for the trabeculectomy and the scleral flaps were apposed with 2 releasable sutures No anti-metabolite was used intra-operatively An Ologen implant (6mm x2mm) was placed abridging the posterior flap edge and water tight conjunctival closure was done. Post-operative recovery was uneventful and at 4 weeks the BCVA was 6/9, N6 with a functional bleb and an IOP of 10 mm HG with no additional medications (Fig 1) At 12 weeks, her VA was 6/9, N6 and her IOP was noted to be 10 mm Hg Bleb evaluation revealed conjunctival necrosis with diffuse leak (Fig 2a and 2b) No signs or symptoms suggestive of inflammation or infection were noted The patient underwent bleb repair with excision of residual implant/necrotic tissue followed by a donor scleral patch graft combined with conjunctival autograft (Fig 3a 3b) The excised tissue was subjected to histopathological analysis (Fig 4) Fig 4. Histopathological analysis revealed extensive conjunctival necrosis, dense chronic inflammation and a foreign body reaction to collagen matrix implant. Special stains for fungi and bacteria were negative and there was no evidence of dysplasia The bleb function was restored following the procedure Her BCVA at 1 month post bleb repair was maintained at 6/9 and IOP was 14 mm Hg without additional medication Discussion We report a rare incidence of acute bleb necrosis without infection in an uneventful Ologen modulated Phaco-trabeculectomy Typical complications documented with Ologen are early leaks, hypotony and encapsulation and failure. Siggel R has recently reported a similar event of non-infective bleb necrosis following combined Ologen and mitomycin C augmented trabeculectomy S Gupta et al have reported a case of blebitis with scleral abcess at 2 months following combined Ologen and MMC modulated trabeculectomy. Our case has had a unique presentation of bleb necrosis despite not using any adjunctive antimetabolites such as MMC Conclusion Acute bleb necrosis following wound modulation with collagen matrix implant could be a rare complication. Our understanding of the biological events involving collagen matrix implants needs further evaluation. References: Chen HS, Ritch R et al. Control of filtering bleb structure through tissue bioengineering in animal model. InvestOphthalmol Vis sci 2000 Aug; 41(9); 2402-2411. Papaconstantinou D, Georgalas I et al. Trabeculectomy with Ologen versus trabeculectomy for the treatment of glaucoma; A pilot study. Acta Ophthalmol 2010 Feb; 88(1): 80-85 Cilino s, Di Pace F ey al. A biodegradable collagen matrix implant versus mitomycin- C as an adjuvant in trabeculectomy: a 24 month randimized clinical truial Eye 2011 Dec 25(12): 1598-606 Angelo P. Tanna, Alfred W. Rademaker, C. Gustavo de Moraes, David G. Godfrey, Steven R. Sarkisian, Jr., Steven D. Vold, Robert Ritch. Collagen matrix vs mitomycin-C in trabeculectomy and combined phacoemulsification and trabeculectomy: a randomized controlled trial. BMC Ophthalmol. 2016; 16: 217. Salvatore Cillino, Alessandra Casuccio, Francesco Di Pace, Carlo Cagini, Lucia Lee Ferraro, Giovanni Cillino. Biodegradable collagen matrix implant versus mitomycin-C in trabeculectomy: five-year follow-up. BMC Ophthalmol. 2016; 16: 24. S Gupta, M Wadhwani, V Sehgal, S Sharma, T Dada. Blebitis with scleral abscess in a case of operated trabeculectomy with mitomycin C and a subcunjunctival ologen implant..Eye (Lond) 2014 Mar; 28(3): 354. Siggel R, Dietlein T. Early atrophy of the conjunctiva after trabeculectomy with mitomycin C and collagen matrix implant. Ophthalmologe. 2017 Apr 28 Fig 3a.1Week, Post Bleb Repair Fig 3b. 8 weeks Post Bleb Repair Fig 1.Week 4 after primary surgery Fig 2. Bleb erosion and leak at 12 weeks