Amniotic membrane in ophthalmology: indications and limitations.

The amniotic membrane remains a useful tool in the treatment of several ophthalmic conditions, especially those related to the ocular surface. However, the 'success' reported in individual case reports and case series is not substantiated in the few published randomised controlled trials. More often than not, it is not as good as existing alternative options and, at best, is as good but with probably an increased cost. The variable outcomes could be related to inter and intra donor variations in the membrane and the depletion or alterations in its constituents subsequent to processing and storage. The membrane thus is a fairly 'non-standardised product' making comparisons of different applications and indications difficult. The potential for 'epidemic' infections, such as HIV, hepatitis B and C, is a serious issue as, in many parts of the world, fresh unquarantined membrane, at times with no tests for the above infectious agents, is being used. The exact mechanism of action of the membrane is not known but the consensus is that it acts as a substrate or scaffold for host cells to populate and thus facilitate healing and repair. The development of a standard 'synthetic membrane' using collagen or polymer matrices impregnated with putative beneficial ingredients, such as growth factors and antimicrobials, is being considered and may prove to be a step in the right direction.