Journal of Current Glaucoma Practice

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VOLUME 10 , ISSUE 3 ( September-December, 2016 ) > List of Articles

Original Article

Porosity of Bleb Capsule declines rapidly with Fluid Challenge

Surinder S Pandav, Craig M Ross, Faisal Thattaruthody, Nirbhai Singh, Natasha Gautam, Stephen Beirne, Gordon G Wallace, Mark B Sherwood, Jonathan G Crowston, Michael Coote

Keywords : 3D Printed implant, Aqueous outflow, Capsular porosity, Filtering surgery, Glaucoma drainage device, Glaucoma, Hydraulic conductivity, Rabbit model, Rapid failure

Citation Information : S Pandav S, M Ross C, Thattaruthody F, Singh N, Gautam N, Beirne S, G Wallace G, B Sherwood M, G Crowston J, Coote M. Porosity of Bleb Capsule declines rapidly with Fluid Challenge. J Curr Glaucoma Pract 2016; 10 (3):91-96.

DOI: 10.5005/jp-journals-10008-1208

License: CC BY-NC 4.0

Published Online: 01-12-2016

Copyright Statement:  Copyright © 2016; Jaypee Brothers Medical Publishers (P) Ltd.


Abstract

Introduction: The porosity of the fibrous capsule around a glaucoma drainage device (GDD) may be the most important functional attribute. The factors that determine capsular porosity are not well understood. Failed GDD surgeries are usually associated with thick impervious capsules and components of aqueous have been implicated in this process. Purpose: In this study, we interrogated the effect of passage of nonaqueous fluid on capsular porosity in mature (but aqueous naive) blebs in a previously reported GDD model (the “Center for Eye Research Australia Implant”). Materials and methods: The study was performed at two centers using 17 New Zealand White (NZW) rabbits. An experimental GDD was implanted into the subconjunctival space but without connection to the anterior chamber. After 28 days, balanced salt solution (BSS) was passed through the implant for 30 to 40 minutes at 12 mm Hg. Capsular porosity was measured as flow (ul_/min) at a constant pressure. Porosity of the capsule was retested at 3 and 6 days. Results: There was a marked reduction in capsular porosity within 3 days of exposure to BSS (fluid challenge). Even though the baseline porosity was significantly different in the two groups (3.00 ± 0.5 ul_/min and 29.67 ± 12.12 ul_/min, p < 0.001), the effect of passage of BSS was similar. Capsular porosity fell by approximately 80% in both groups from baseline after single BSS challenge. Capsular thickness was significantly less in Advanced Eye Center (AEC) rabbits at baseline. There was no change in the capsular thickness before and after single fluid challenge. Conclusion: Passage of BSS at physiological pressures for under 40 minutes caused marked reduction in the porosity of the fibrous capsule within 3 days. This was not associated with any significant thickening of the fibrous capsule within this time frame.


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  1. Suzuki R, Dickens CJ, Iwach AG, Hoskins HD Jr, Hetherington J Jr, Juster RP, Wong PC, Klufas MT, Leong CJ, Nguyen N. Long-term follow-up of initially successful trabeculectomy with 5-fluorouracil injections. Ophthalmology 2002 Oct;109(10):1921-1924.
  2. Chen TC, Wilensky JT, Viana MA. Long-term follow-up of initially successful trabeculectomy. Ophthalmology 1997 Jul;104(7):1120-1125.
  3. Heuer, DK.; Barton, K.; Grehn, F.; Shaarawy, T.; Sherwood, M. Consensus of definitions of success. In: Shaarawy T, Grehn F, Sherwood M, editors. Guidelines on design and reporting of glaucoma surgical trials; World Glaucoma Association. Amsterdam: Kugler; 2008. [Accessed 2016 June 30]. p. 15-24. Available from: www.worldglaucoma.org/Download/dl_files.php?id=1.
  4. Gardiner BS, Smith DW, Coote M, Crowston JG. Computational modeling of fluid flow and intra-ocular pressure following glaucoma surgery. PloS One 2010 Oct;5(10):1-11.
  5. Gedde SJ, Schiffman JC, Feuer WJ, Herndon LW, Brandt JD, Budenz DL; Tube versus Trabeculectomy Study Group. Treatment outcomes in the Tube Versus Trabeculectomy (TVT) study after five years of follow-up. Am J Ophthalmol 2012 May;153(5):789-803.
  6. Budenz DL, Barton K, Gedde SJ, Feuer WJ, Schiffman J, Costa VP, Godfrey DG, Buys YM; Ahmed Baerveldt Comparison Study Group. Five-year treatment outcomes in the Ahmed Baerveldt comparison study. Ophthalmology 2015 Feb;122(2):308-316.
  7. Minckler DS, Shammas A, Wilcox M, Ogden TE. Experimental studies of aqueous filtration using the Molteno implant. Trans Am Ophthalmol Soc 1987;85:368-392.
  8. Molteno ACB, Fucik M, Dempster AG, Bevin TH. Otago glaucoma surgery outcome study: Factors controlling capsule fibrosis around Molteno implants with histological correlation. Ophthalmology 2003 Nov;110(11):2198-2206.
  9. Ayyala RS, Harman LE, Michelini-Norris B, Ondrovic LE, Haller E, Margo CE, Stevens SX. Comparison of different biomaterials for glaucoma drainage devices. Arch Ophthalmol 1999 Feb;117(2):233-236.
  10. Ayyala RS, Michelini-Norris B, Flores A, Haller E, Margo CE. Comparison of different biomaterials for glaucoma drainage devices: Part 2. Arch Ophthalmol 2000 Aug;118(8):1081-1084.
  11. Nguyen DQ, Ross CM, Li YQ, Pandav S, Gardiner B, Smith D, How AC, Crowston JG, Coote MA. A model to measure fluid outflow in rabbit capsules post glaucoma implant surgery. Invest Ophthalmol Vis Sci 2012 Sept;53(11):6914-6919.
  12. Ross C, Pandav S, Li YQ, Nguyen DQ, Beirne S, Wallace GG, Shaarawy T, Crowston JG, Coote M. Measuring bleb capsule porosity with a novel implant and measurement system. JAMA Ophthalmol 2015 May;133(5):549-554.
  13. Chang MR, Cheng Q, Lee DA. Basic science and clinical aspects of wound healing in glaucoma filtering surgery. J Ocul Pharmacol Ther 1998;14(1):75-95.
  14. Seibold LK, Sherwood MB, Kahook MY. Wound modulation after filtration surgery. Surv Ophthalmol 2012 Nov-Dec;57(6): 530-550.
  15. Levick JR. Flow through interstitium and other fibrous matrices. Q J Exp Physiol 1987 Oct;72(4):409-438.
  16. Hong C-H, Arosemena A, Zurakowski D, Ayyala RS. Glaucoma drainage devices: a systematic literature review and current controversies. Surv Ophthalmol 2005 Jan-Feb;50(1):48-60.
  17. Sharplin J, Franko AJ. A quantitative histological study of strain-dependent differences in the effects of irradiation on mouse lung during the intermediate and late phases. Radiat Res 1989 Jul;119(1):15-31.
  18. Epstein E. Fibrosis response to aqueous. Its relationship to glaucoma. Br J Ophthalmol 1959 Dec;43(11):641-647.
  19. Herschler J, Claflin AJ, Fiorentino G. The effect of aqueous humor on the growth of subconjunctival fibroblasts in tissue culture and its implications for glaucoma surgery. Am J Ophthalmol 1980 Feb;89(2):245-249.
  20. Tripathi RC, Li J, Chan WF, Tripathi BJ. Aqueous humor in glaucomatous eyes contains an increased level of TGF-beta 2. Exp Eye Res 1994 Dec;59(6):723-727.
  21. Clark, RAF.; Henson, PM. The molecular and cellular biology of wound repair. New York: Plenum Press; 1988. p. 13-32.
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