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The variation in transparency of amniotic membrane\ud used in ocular surface regeneration

By Che John Connon, James Doutch, Bo Chen, Andy Hopkinson, Jod Mehta, Takahiro Nakamura, Shigeru Kinoshita and Keith Meek

Abstract

Background/aims: Scant consideration has been given\ud to the variation in structure of the human amniotic\ud membrane (AM) at source or to the significance such\ud differences might have on its clinical transparency.\ud Therefore, we applied our experience of quantifying\ud corneal transparency to AM.\ud Methods: Following elective caesarean, AM from areas\ud of the fetal sac distal and proximal (ie, adjacent) to the\ud placenta was compared with freeze-dried AM. The\ud transmission of light through the AM samples was\ud quantified spectrophotometrically; also, tissue thickness\ud was measured by light microscopy and refractive index by\ud refractometry.\ud Results: Freeze-dried and freeze-thawed AM samples\ud distal and proximal to the placenta differed significantly in\ud thickness, percentage transmission of visible light and\ud refractive index. The thinnest tissue (freeze-dried AM) had\ud the highest transmission spectra. The thickest tissue\ud (freeze-thawed AM proximal to the placenta) had the\ud highest refractive index. Using the direct summation of\ud fields method to predict transparency from an equivalent\ud thickness of corneal tissue, AM was found to be up to\ud 85% as transparent as human cornea.\ud Conclusion: When preparing AM for ocular surface\ud reconstruction within the visual field, consideration should\ud be given to its original location from within the fetal sac\ud and its method of preservation, as either can influence\ud corneal transparency

Topics: 571, 573
Publisher: BMJ Publishing Group
Year: 2010
OAI identifier: oai:centaur.reading.ac.uk:1680

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