Amniotic membrane therapy has become a popular procedure in the last two decades. This treatment allows for a biological bandage to be applied to the ocular surface to promote surface reconstruction and healing.
WHAT IS AMNIOTIC MEMBRANE TISSUE?
The amniotic membrane is a thin layer of skin that lines the inside of the placenta. The purpose of the amniotic membrane is to protect the fetus against harm and is naturally therapeutic to help the fetus develop. The collagen of the membrane is what makes the tissue so special, because it contains specialized proteins as well as growth factors.
Amniotic Membrane tissue is taken as a graft from elected cesarean section and is handled in sterile conditions to be used for ocular therapy.
WHAT ARE AMNIOTIC MEMBRANE GRAFTS?
There are three different types of amniotic membrane grafts that are used in ocular therapy.
Surgical Graft: This type of grafting is used when a permanent graft is needed to restore tissue. The graft is surgically sutured onto the tissue of the eye, and over time the membrane dissolves. This treatment is most commonly used during conjunctiva reconstruction- when there is a benign growth of the inner eye.
Dehydrated Sutureless: Popularly used for ocular scarring, this grafting procedure can be done by ophthalmologists and optometrists. With this procedure a circular tissue graft is applied to the desired area of the cornea and flattened to the surface without an outer stabilizing ring. A lid speculum is required for this procedure as it helps the amniotic membrane graft to stay in place on the cornea, keeping the surrounding eyelid away. Steady hands are needed for the insertion and removal of this procedure to make sure the lid speculum does not disrupt the graft, or move the contact lens.
Cryopreserved Sutureless: Since the dehydrated sutureless graft is more of a challenging procedure due to the insertion of the lid speculum, the cryopreserved sutureless is a popular choice, because optometrists can perform the treatment at their own clinic. With this procedure the amniotic membrane is applied with an ophthalmic conformer ring. The ophthalmic conformer ring comes in various different levels of thickness depending on how severe the eye condition is and resembles a contact lens.
WHAT ARE THE INDICATIONS OF NEEDING AMNIOTIC MEMBRANE THERAPY?
Amniotic membrane therapy is used for any condition that damages the ocular surface, underlying stromal inflammation or any condition that can cause permanent scarring of the ocular surface affecting the patient’s vision.
Conditions that may require amniotic membrane therapy include:
- Shield ulcers
- Neurotrophic corneal epithelial defects
- Corneal abrasions, ulcers and burns
- Filamentary keratitis
- Dry eye and exposure keratopathy
- Recurrent corneal erosion
- Salzmann’s nodular degeneration
- Chemical and thermal burns
- Post-infectious keratitis
Determining what procedure should be preformed for each condition are patient and case dependent. Some amniotic membrane therapies may last longer than others, as the membrane will dissolve or be absorbed at different rates.
WHAT ARE THE RISKS OF AMNIOTIC MEMBRANE TRANSPLANTS?
With allogeneic tissue there is an implied risk of infectious disease transmission, however all caesarean section donors are thoroughly screened for communicable diseases, such as HIV, hepatitis and syphilis. The grafted membrane that is taken from cleared donors is then stored in sterile conditions depending on the grafting procedure the sample is to be used for. The membrane tissue is either stored for fresh use or cryopreserved at a temperature of -80 degrees Celsius.
If you have any further questions regarding the transplantation of this particular procedure, feel free to comment on our Facebook page, or book an appointment for further consultation.