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Study links subfoveal fibrosis and classic CNV in AMD
Subfoveal fibrosis correlated with lower baseline BCVA, longer duration of disease and greater vision loss.
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Subfoveal fibrosis in age-related macular degeneration was associated with the development of classic choroidal neovascularization, according to a study.
Development of subfoveal fibrosis also correlated with an additional two lines of vision loss and longer duration of disease compared with eyes that did not develop fibrosis, the study authors said.
“The most important finding was that the subfoveal fibrosis together with retinal atrophy were actually most prominent in eyes with predominantly classic lesions at baseline,” co-author Sara Brandi Bloch, MD, said in an interview with Ocular Surgery News. “Eyes that had classic lesions were more prone to develop subretinal fibrosis with and without retinal atrophy compared to patients with occult or minimally classic lesions.”
Bloch said there is a critical relationship between the retinal pigment epithelium (RPE) and fibrosis and the potential impact of combined therapies.
“The retinal pigment epithelium seems to make all the difference. Fibrosis that destroys photoreceptors develops when the RPE has been destroyed or penetrated by the invading new vessels,” she said. “Unfortunately, we have no way of protecting or strengthening the RPE today, but it is going to be interesting to see if future therapies for dry AMD can promote CNV control in wet AMD.”
Sara Brandi Bloch
Patients and methods
The retrospective study, published in the American Journal of Ophthalmology, included 197 eyes of 197 patients with choroidal neovascularization (CNV) related to AMD without subfoveal fibrosis at presentation.
Patients received three 0.5-mg injections of Lucentis (ranibizumab, Genentech) at 4-week intervals; subsequent injections were given as needed. Patients who had undergone other treatments were excluded from the study.
Optical coherence tomography and color fundus photography were used to evaluate subfoveal fibrosis and retinal atrophy from 16 weeks after the first ranibizumab injection.
“In addition to using fundus photographs to grade subfoveal fibrosis, we also used OCT to assess the RPE and the neovascular membrane,” Bloch said. “Multimodal imaging is the way forward, and there is a lot more that potentially can be done with modern OCT, fundus autofluorescence imaging, adaptive optics photoreceptor imaging, etc.”
The mean interval between diagnosis and treatment was 17.2 days.
Mean follow-up was 1.8 years. Visual acuity data for 174 eyes were available at final follow-up. The main outcome measure was presence of subfoveal fibrosis at final follow-up.
Outcomes and observations
Eyes with predominantly classic CNV had significantly higher odds of developing any subfoveal fibrosis than eyes with minimally classic or occult CNV (P < .0001).
There was no significant relationship between CNV size at baseline and development of fibrosis.
Eyes with a baseline ETDRS best corrected visual acuity of 40 letters or worse had significantly greater odds of developing any type of fibrosis than eyes with baseline BCVA of 70 letters or more.
Eyes with prominent fibrosis lost 8.5 more letters of vision than those without fibrosis. Eyes with fibrosis and foveal atrophy lost 10.3 more letters than those without fibrosis.
BCVA was 12.2 letters lower in eyes with type 2 lesions before initiation of treatment than in those with type 1 lesions; the difference was statistically significant (P = .0003). However, eyes with type 2 lesions did not lose significantly more letters than those with type 1 lesions.
An interval of 15 days or more between diagnosis and treatment was associated with greater odds of any fibrosis development than an interval of less than 15 days.
“This is preliminary, and it is retrospective,” Bloch said. “We need to confirm this with a prospective study.” – by Matt Hasson