By Fred Gebhart
SAN FRANCISCO -- October 27, 2009 -- Bevacizumab is currently the most effective treatment option for corneal neovascularisation, over lasers and thermal treatments, according to a report presented here at the 2009 Joint Meeting of the American Academy of Ophthalmology and Pan-American Association of Ophthalmology (AAO-PAAO).
Corneal neovascularisation typically presents as stromal neovascularisation or as vascular pannus, said Luis Izquierdo, Jr, MD, Instituto Oftalmo Salud, Lima, Peru, on October 25.
Both conditions are associated with a host of pathologies ranging from viral, fungal, bacterial, and parasitic infections to degenerative and congenital disorders, traumatic injuries, and more.
Complications from neovascularisation include corneal scarring, oedema, lipidic deposition, and inflammation.
Not surprisingly, invasive ophthalmological procedures are associated with high rates of neovascularisation. In penetrating keratoplasty (PK), for example, up to 41% of treated eyes show signs of neovascularisation 6 to 9 months after surgery. The risk of neovascularisation increases when suture knots are buried in the host stroma, active blepharitis is present, or a large recipient bed is used.
The rate of corneal neovascularisation may be as high as 60% during active atopic keratoconjunctivitis, and any infectious keratitis may induce corneal neovascularisation, Dr. Izquierdo continued. Herpes family viruses are the primary infective agents associated with neovascularisation in PK buttons.
"Multiple growth factors are involved in neovascularisation," he noted. Major factors include vascular endothelial growth factor, fibroblast growth factor, and matrix metalloproteinases, a group of zinc-binding proteolytic enzymes.
Various medical and surgical treatments are available, said Dr. Izquierdo. Topical corticosteroids are most effective against new vessels, whereas nonsteroidal anti-inflammatory agents are most effective against rapidly growing vessels. The newest treatment is topical or subconjunctival bevacizumab.
Surgical treatments include laser photocoagulation, electrical coagulation, fine-needle diathermy, photodynamic therapy, and transplantation of conjunctival, limbal, or amniotic membrane. Overall, laser and diathermy are less effective, whereas photodynamic procedures may be more helpful.
"We use bevacizumab as the most effective treatment option," he said. "Lasers do not seem to work well, and thermal treatments have a high recurrence rate in our experience." About 30% of bevacizumab patients need a second treatment within 2 months for complete neovascularisation remission.
"The real problem is that all we have is case reports," said Dr. Izquierdo. "What we really need is good clinical trials, but they have not been done yet."
[Presentation title: Corneal Neovascularization. Abstract SYM 56]
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