Ocular surface rehabilitation: Application of human amniotic membrane in high-risk penetrating keratoplasties

BACKGROUND

Human amniotic membrane is a versatile tool for management of ocular surface disorders. This study evaluates the effect of cryopreserved human amniotic membrane (hAM) on one-year survival of penetrating keratoplasties (PKP) in high-risk recipients.

METHOD

This is a retrospective noncomparative cohort study of 58 consecutive eyes undergoing PKP with concurrent placement of a self-retained cryopreserved hAM (PROKERA®) at a tertiary care center from January 2009 to July 2010.

RESULTS

Mean patient age was 66.7 ± 17.2 years and 30 (54%) were males. 51 eyes were pseudophakic and one aphakic. 27 eyes were glaucomatous; 24 had glaucoma drainage device and 2 had previous endocyclophotocoagulation. 12 patients had PKP for the first time and 46 had repeat PKP (average number of prior PKP = 1.63 ± 1.1, range: 1-5). Risk factors for graft failure included repeat PKP (79.3%), corneal neovascularization (51.7%), preexisting glaucoma (46.6%), and presence of anterior synechiae (37.9%). Both First Transplant and Repeat Transplant groups had similar survival rates until 6 months after transplant (75% vs 74%, odds ratio = 1.06, p = 1.00). At 12 months, First Transplant group showed a better survival rate (67% vs 43%, odds ratio = 2.60, p = 0.20). Eyes with >3 risk factors had a higher graft failure rate (odds ratio = 5.81, p = 0.003).

CONCLUSION

Survey of the literature suggests that high-risk PKP with concurrent hAM placement demonstrate comparable graft survival. Presence of multiple risk factors is associated with poor survival.

Conjunctival squamous metaplasia on amniotic membrane in Stevens-Johnson syndrome: a case report

BACKGROUND

To present a case of conjunctival growth on the amniotic membrane and subsequent pathology revealing conjunctival squamous metaplasia in a patient with Stevens-Johnson syndrome.

CASE PRESENTATION

A 21-year-old female presented with painful, blurred vision in both eyes for two weeks. She was diagnosed with Stevens-Johnson syndrome 5 weeks before. Due to bilateral corneal epithelial defects, ProKera®, an amniotic membrane corneal bandage with a polycarbonate ring, was placed in both eyes. However, three weeks later, a slit-lamp examination revealed vascularized tissue growth from the palpebral conjunctiva to the amniotic membrane, along with symblepharon formation in the left eye. The patient underwent conjunctival biopsy, amniotic membrane removal, and symblepharon release. Pathology report showed the growth of squamous epithelium on the acellular amniotic membrane. Immunohistochemistry further supported the diagnosis, revealing squamous markers through p40 staining and highlighting the presence of the amniotic membrane using trichrome stain. Three months later, the patient's visual acuity had improved to 20/25 and no symblepharon was noted.

CONCLUSIONS

This is the first case of conjunctival squamous metaplasia on amniotic membrane associated with Stevens-Johnson syndrome. Our case indicates that, despite the anti-inflammatory properties of amniotic membrane, conjunctival squamous metaplasia may arise after amniotic membrane grafting due to intense inflammation in Stevens-Johnson syndrome. Clinicians should conduct regular monitoring before amniotic membrane dissolution to preclude the development of conjunctival squamous metaplasia on the membrane and potential invasion into the cornea.