Epithelial or Fibrous Ingrowth
Epithelial ingrowth (or downgrowth) is a rare complication of intraocular surgery (Fig 11-2) or trauma. It is characterized by the growth of epithelium intraocularly with proliferation over the corneal endothelium, trabecular meshwork, and/or iris surfaces. Epithelial cells introduced into the anterior chamber during surgery may adhere to intraocular structures and proliferate as a cellular mass or membrane. Alternatively, a sheet of epithelium from the ocular surface may grow through a wound or incision. Signs of epithelial ingrowth include elevated IOP, clumps of cells floating in the anterior chamber, a grayish retrocorneal membrane (usually with overlying corneal edema), an abnormal iris surface, and pupillary distortion. Green laser burns applied to the membrane on the iris surface will appear white if epithelial cells are present, which helps confirm the diagnosis.
Fibrous ingrowth (Fig 11-3) is more prevalent than epithelial ingrowth. Fibrovascular tissue, rather than epithelial cells alone, proliferates from a penetrating wound. Fibrous ingrowth progresses more slowly than epithelial ingrowth and may be self-limited. It is a common cause of corneal graft failure and may result in the formation of peripheral anterior synechiae (PAS) and secondary angle-closure glaucoma.
Risk factors for both epithelial and fibrous ingrowth include trauma, prolonged inflammation, wound dehiscence, delayed wound closure, vitreous incarceration, and Descemet membrane tears. Many surgical treatments, including membrane excision and fistula repair, have been suggested, but none has been uniformly successful. Local application of cryotherapy or 5-fluorouracil has been effective. Elevated IOP is often difficult to control with medical therapy, and filtering procedures or tube shunt surgery may be necessary, as discussed in BCSC Section 10, Glaucoma.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.