In cases of severe, unresponsive dry eye or a non-healing defect on the corneal surface, the temporary placement of either a wet or dry amniotic membrane over the cornea may help solve the problem.
Taken and processed after a full-term delivery, this material has tissue growth factors and anti-inflammatory components that help heal and regrow corneal cells after injury. Two types of amniotic membranes are available, and both have their pros and cons.
Initially more comfortable, the dry membrane comes as a thin round disc that is placed on the eye and then covered by a soft lens to keep it in place. The eye is made numb with a drop before placement, and it’s kept moist with the use of lubricating drops. Patients can go about their normal routine, but it will be a bit blurry in that eye until the membrane is removed in a few days. This type of membrane has a few less growth factors than the wet variety.
The wet membrane is held in place by a plastic ring that is inserted onto the eye, again after topical anesthesia; however, the eye has to be taped partly closed to keep the ring from moving too much when blinking. It is also removed after a few days. This type can be a bit more limiting in terms of vision and cosmetic appearance than the dry membrane, but both are safe, relatively comfortable and effective – though no medical treatment is 100% successful. Medication and lubrication can and should be used with devices in place.