Histologic findings after amniotic membrane graft in the human cornea

To describe the histopathologic findings in the human cornea several months after a stromal amniotic membrane graft. To show the clinicopathologic correlation after the graft in two cases with different follow-up times.

Two interventional case reports with clinicopathologic correlation.

Two patients with neurotrophic corneal ulcer unresponsive to medical treatment (one with stromal vascularization and the other without stromal vascularization).

Amniotic membrane graft was performed in both patients to treat the neurotrophic ulcer. Three and 7 months after amniotic membrane grafting, a penetrating keratoplasty was needed, and the removed corneas were analyzed.

Clinical and histopathologic examinations, including routine histopathologic and immunohistochemical studies.

Complete epithelialization was observed on histologic examination over the basement membrane of the amniotic membrane graft. The amniotic membrane was slowly reabsorbed in the cornea without stromal vascularization with no inflammatory reaction produced. In the cornea that had stromal vascularization the amniotic membrane was rapidly reabsorbed because of the presence of abundant inflammatory cells. Once reabsorbed, the amniotic membrane was replaced by new fibrotic stroma, that was different from that found in the rest of the cornea but that helped to maintain corneal thickness.

The amniotic membrane graft allows for correct epithelialization in cases of neurotrophic corneal ulcer. Once the amniotic membrane is reabsorbed, it is replaced by a new fibrotic stroma, which can reduce corneal transparency. In corneas that have no stromal vascularization, the graft may remain in the stroma for many months, compromising corneal transparency during this period.