Although these products originate from placental tissue, the term “amniotic membrane” does not mean that every product is biologically identical.
How the tissue is preserved, processed, sterilized, stored, and prepared for use can influence its physical structure and biological characteristics.
Cryopreserved Amniotic Membrane
Cryopreserved membrane is preserved at very low temperatures, commonly around -80°C, using a controlled cryopreservation process.
Cryopreservation has a long history in ophthalmology and is intended to preserve the tissue in a condition relatively close to its native architecture.
These products generally require frozen storage and maintenance of a cold chain.
Patient-friendly explanation:
The membrane is stored frozen to preserve the tissue in a state relatively close to its original biological structure.
Dehydrated or Dry-Preserved Amniotic Membrane
With dehydrated tissue, most of the water is removed through a controlled drying process.
These membranes can generally be stored at room temperature and are rehydrated by the patient’s natural tears or sterile solution when placed on the ocular surface.
Patient-friendly explanation:
The water has been removed from the membrane so it can be stored at room temperature and then rehydrates when placed on the eye.
Lyophilized or Freeze-Dried Amniotic Membrane
Lyophilization is a specialized preservation process in which the tissue is first frozen and water is then removed under controlled vacuum conditions.
This allows the tissue to be stored for extended periods without conventional frozen storage.
Patient-friendly explanation:
The membrane is preserved by first freezing the tissue and then carefully removing its water under controlled conditions.
Air-Dried, Vacuum-Dried, and Controlled-Temperature Membranes
Other preservation systems remove moisture from the tissue using carefully controlled combinations of temperature, pressure, airflow, or vacuum.
Manufacturers may use proprietary processes intended to preserve particular structural or biological characteristics while allowing room-temperature storage.
Other Processed Placental-Tissue Products
Placental tissue may also be processed into decellularized, micronized, homogenized, extracted, or combined amnion/chorion products.
These products should not automatically be considered interchangeable with an intact ophthalmic amniotic membrane.
The processing method, intended use, supporting clinical evidence, and insurance coverage may differ between products.
The doctor selects an appropriate membrane based upon the patient’s diagnosis, condition of the ocular surface, treatment objectives, and other clinical factors.
The word “amniotic” describes the tissue’s origin. It does not mean that every amniotic product is processed the same way or preserves exactly the same biological characteristics.
Insurance Coverage and Medical Necessity: Amniotic membrane treatment may be covered by Medicare or commercial insurance when applicable medical-necessity requirements are satisfied. Coverage varies according to diagnosis, severity of disease, objective clinical findings, previous treatments, individual insurance benefits, and payer policy. Prior authorization or verification of benefits does not guarantee payment. When possible, our office will review applicable benefits and expected patient financial responsibility before treatment.