PHOTO ESSAY

Autofluorescence Patterns in a Case of Best Vitelliform Macular Dystrophy

DIMITRIOS STYLIANOS KONTADAKIS, MD · STEFANO VERGALLO, MD · ALESSANDRO PAPAYANNIS, MD · MAURIZIO BATTAGLIA PARODI, MD · FRANCESCO BANDELLO, MD, FEBO

A 42-year-old female was referred to the Department of Ophthalmology of the University of Udine for an ophthalmologic examination. She had been previously diagnosed with Best vitelliform macular dystrophy (BVMD) in 1999. General medical history was unremarkable. The father was also affected by BVMD in advanced stage.

EXAMINATION AND DIAGNOSIS

Visual acuity was 6/10 in both eyes. Intraocular pressure was 15 mmHg. Slit-lamp examination of the anterior segment revealed no alteration. Biomicroscopic fundus examination confirmed the previous diagnosis of BVMD. Indeed, yellow material at the level of the retinal pigment epithelium (RPE) was detectable at the posterior pole, in association with uneven pigmentary changes (Figure 1).

Figure 1. Color photograph of both eyes. Large deposition of yellowish material at the RPE level is associated with irregular pigmentary changes.

Electrooculogram was extinct. Photopic and scotopic electroretinograms turned out to be normal.

Optical coherence tomography (OCT) scans showed a well-defined material accumulation underneath the RPE in the right eye, with more pronounced cystic changes in the left eye (Figure 2).

Figure 2. OCT images of both eyes showing a subretinal pigment epithelium conical mound of moderately reflective material in the right eye (left scan) and a larger cystic space in the left eye (right scan).

Fundus autofluorescence imaging was obtained using a confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph 2; Heidelberg Engineering, Dossenheim, Germany).

Blue-light autofluorescence showed a spoke-like pattern characterized by several lines of hyper-autofluorescence beginning from the central area, where on the contrary, the signal was decreased to absent (Figure 3).

Figure 3. Blue-light autofluorescence of both eyes revealing a spoke-like distribution of hyper-autofluorescence changes next to a central area of decreased to absent signal.

Near-infrared (NIR) autofluorescence of both eyes revealed the absence of the elliptical area of high fluorescence centered on the fovea, which is typical of normal subjects (Figure 4). Indeed, a spoke-like aspect resembling that detected with blue-light autofluorescence was visible.

Figure 4. Near-infrared autofluorescence. The pattern turned out to be very similar to that detectable on blue-light autofluorescence. A spoke-like distribution of the autofluorescence signal was detectable, surrounding a central area of decreased response.

DISCUSSION

BVMD is an early-onset autosomal dominant disorder with variable penetrance, caused by mutation in the bestrophin gene.^1-3 The disorder is clinically characterized by large deposits of lipofuscin-like material in the subretinal space. The phenotypic manifestation is characterized by a "vitelliform" macular lesion, which resembles an egg yolk. BVMD is a continuing disease, the affected macular area becoming more and more involved with a scrambledegg aspect and progressive visual acuity deterioration.^1,2

The electrofunctional and the OCT features of BVMD have already been well-described.^1,3,5 On the contrary, only a few studies have reported on the blue-light autofluorescence patterns typical of BVMD.^6-9 Overall, several patterns have been described, including a spokelike pattern and a diffuse pattern, together with a variety of combinations of hyper- and hypo-autofluorescence signals. The present case shows a spoke-like pattern both on blue-light and NIR autofluorescence. Bearing in mind that blue-light autofluorescence is related to the lipofuscin deposition, whereas the NIR autofluorescence reflects the presence of melanin,⁴ we may speculate that in this case the melanin changes parallel the lipofuscin deposition. Near-infrared autofluorescence has been reported as useful in the characterization of adult-onset foveomacular vitelliform dystrophy¹⁰ and further studies are required to assess the significance of near-infrared autofluorescence alteration in macular dystrophies. RP

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