Autofluorescence of basal laminar drusen

To compare noninvasive autofluorescence (AF) photography with conventional fundus photography and fluorescein angiography (FA) in the detection of basal laminar drusen (BLD).

A retrospective case review of 20 patients with BLD studied with AF and conventional imaging was performed. Three selected patients with different degrees of BLD are presented. AF imaging employed an excitation filter at 580 nm and a barrier filter at 695 nm with acquisition by a Topcon 50X fundus camera. Corresponding detail regions in each image were enlarged for comparison. The AF detail image was registered by a projective transformation in Matlab (Mathworks 7.0, Natick, MA) with the color photograph/red free photograph (RF) and/or FA image detail for exact superimposition in Photoshop and lesion comparison.

Each visible drusen in the color or RF photograph corresponded when superimposed to a focal hypoautofluorescent lesion in the AF image. However, similar to the starry sky pattern in FA, the AF lesions significantly outnumbered the clinically evident drusen. When BLD lesions were not advanced enough to show the classic starry sky fluorescein hyperfluorescence, the BLD were detectable with AF.

In our case series, AF imaging demonstrated a higher level of sensitivity when compared with conventional fundus photography and is less invasive than FA for the detection of BLD. Fundus AF, therefore, is valuable for diagnosing and following BLD, particularly since these patients are at risk for development of pseudovitelliform detachment which may simulate CNV.