Clinical features of drusenoid pigment epithelial detachment in age related macular degeneration

Aim: To analyse clinical features of drusenoid pigment epithelium detachment (PED) in age related macular degeneration. Methods: 61 eyes of 32 patients with untreated drusenoid PED were followed for an average of 4.6 years ( range 1 - 17 years). Drusenoid PED was defined as K disc diameter ( DD) of confluent soft drusen under the centre of the macula. All patients underwent visual acuity measurement, biomicroscopic fundus examination, stereoscopic colour photograph, and fluorescein and indocyanine green angiography. Optical coherence tomography was performed in selected cases at the last examination. Kaplan Meier survival analysis was performed to estimate the probability of complications. Results: Three different natural outcomes were identified: persistence of drusenoid PED (38%), development of geographic atrophy ( 49%), and choroidal neovascularisation (CNV) (13%). Based on Kaplan Meier survival analysis, drusenoid PED had a 50% of chance of developing geographic atrophy after 7 years. If the drusenoid PED was greater than 2 DD or was associated with metamorphopsia at initial presentation, progression to atrophy or ingrowth of CNV occurred after 2 years (p< 0.01). Indocyanine green angiography confirmed fluorescein angiographic features or ascertained the presence of CNV when fluorescein angiography was equivocal. Optical coherence tomography was helpful in distinguishing coalescent soft drusen from drusenoid PED and disclosed the accumulation of sub or intraretinal fluid in eyes with CNV. Conclusion: Drusenoid PED size greater than 2 DD and metamorphopsia were risk factors identified at presentation which affected prognosis. The evaluation of the eyes at risk requires the use of all imaging means in order to ascertain the diagnosis of CNV. At long term ( over 10 years), geographic atrophy and CNV had occurred in 75% and 25% respectively, with a poor visual outcome.