Chorion-free, freeze-dried amniotic membranes (FD-AM) are likely an effective substitute for cryopreserved amniotic membranes (C-AM) in the treatment of corneal ulcers, according to a study published in Cornea. 

Researchers included 50 participants who received either FD-AM (n=28) or C-AM procedures (n=22) in the study. They obtained demographic data for all patients and compared a variety of baseline characteristics between the groups. Postoperative follow up occurred at intervals of 72 hours, 1 month, and 3 months. 

The investigators observed similar demographics between the 2 groups. They categorized disease etiologies as bacterial, herpes, acanthamoeba, fungal, neurotrophic keratitis, chemical corneal burn, or other, and sought associations between the groups (25%, 33%, P =.56; 11%, 14% P =.75; 7%, 5%, P =.70; 0%, 5%, P =.25; 11%, 14%, P =75; 11%, 5%, P =.43; 36%, 27%, P =.53, for the FD-AM and C-AM groups, respectively).  Age and etiology revealed no association with ulceration size (P =.15 and P =.38, respectively), and corneal ulcer depth was similar between the 2 groups (64% and 77%, respectively, P =.32). The difference in follow up time was the only statistically significant factor between the groups (18.2±9.5 months C-AM, 3.0±1.4 months F-AM; P <.01).

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Likewise, complications including infection, descemetocele, and perforation were uncommon and comparable between the groups (0%, 0%; 4%, 5%; 7%, 5%,  FD-AM and C-AM groups, respectively).

“Corneal healing was not different between FD-AM and C-AM [when] used as an overlay patch, regardless of the depth of the ulcer,” according to the investigators. Regardless of the treatment method used “at 1 month, we were not able to show any difference for corneal healing in both deep stromal ulcers and anterior stromal ones.”

Study limits include a single center design, retrospective nature, small sample size, and possible confounding due to the use of soft bandage lenses. 


Memmi B, Leveziel L, Knoeri J, et al. Freeze-dried versus cryopreserved amniotic membranes in corneal ulcers treated by overlay transplantation: a case control study. Cornea. 2022; 41(3): 280-285. doi:10.1097/ICO.0000000000002794