ORIGINAL RESEARCH ARTICLE

Annular fundus autofluorescence abnormality in a caseof macular dystrophy

Charlotte M. Poloschek Æ Lutz L. Hansen ÆMichael Bach

Received: 3 November 2006 / Accepted: 29 October 2007 / Published online: 16 November 2007

� Springer-Verlag 2007

Abstract Purpose: To present a case of macular

dystrophy with early changes in fundus autofluores-

cence. Methods: A 20-year-old woman with a recent

loss of visual acuity and onset of photophobia was

examined. Color vision and visual field testing, fluo-

rescein angiography, full-field and multifocal

electroretinograms as well as fundus autofluorescence

were performed. Results: Best-corrected visual acuity

was 20/100 (right eye) and 20/60 (left eye). There was a

red-green color vision defect and a relative central

scotoma in both eyes. Ophthalmoscopy and fluorescein

angiography were essentially normal, the presence of a

dark choroid was debatable. Full-field ERG responses

were normal, but the multifocal ERG showed severely

reduced responses in the macular region. Both eyes

showed a slight circular parafoveolar increase of fundus

autofluorescence. Conclusion: Besides multifocal

ERG, fundus autofluorescence aids to objectively

assess the manifestation of macular dystrophies but

does not discern between different types in early stages.

Keywords Fundus autofluorescence � Central cone

dystrophy � Full-field electroretinogram � Hereditary

retinal dystrophy � Macular dystrophy � Occult

macular dystrophy � Multifocal electroretinogram �Stargardt macular dystrophy-fundus flavimaculatus

Introduction

The early stages of macular dystrophies can be very

subtle with hardly any visible fundus changes at all.

One example is occult macular dystrophy (OMD)

[1, 2], also known as ‘‘central cone dystrophy’’ [3].

The only known objective signs of this disease are

reduced focal ERGs and/or reduced amplitudes in the

multifocal ERG and a reduced foveal thickness in

optic coherence tomography [1, 2, 4–6]. The fundus

in early Stargardt macular dystrophy-fundus flavima-

culatus (SMD-FFM) might show minor central

pigment irregularities or loss of foveal reflexes only,

multifocal ERG amplitudes can be reduced to a

variable extent, the fluorescein angiogram might

display a dark choroid, and fundus autofluorescence

is altered [7–9]. Here we report a macular dystrophy

case in an early stage of manifestation sharing some

characteristics with early SMD-FFM with a patho-

logic pattern of fundus autofluorescence (AF).

Case report

A 20-year-old woman was referred to our hospital for

unexplained visual loss in both eyes. She complained

of reduced visual acuity and photophobia for 5 months

and color vision abnormalities for 2 months. Family

and past histories were unremarkable. Visual acuity

was 20/20 in both eyes at 19 years of age. At present

best-corrected visual acuities were 20/200 (right eye),

C. M. Poloschek (&) � L. L. Hansen � M. Bach

Department of Ophthalmology, University of Freiburg,

Killianstr. 5, 79106 Freiburg, Germany

e-mail: charlotte.poloschek@uniklinik-freiburg.de

123

Doc Ophthalmol (2008) 116:91–95

DOI 10.1007/s10633-007-9097-2

20/100 (left eye) in standard room illumination and

20/100 (right eye), 20/60 (left eye) in dim light. The

patient was dark pigmented. Anterior segment and

fundus examinations were essentially normal, the

foveae showed minor central irregularities of the

retinal pigment epithelium (RPE). Figure 1 demon-

strates well-preserved macular reflexes. Foveal

reflexes were present as well but could not be captured

by photography of the left fundus due to patient’s

unrest during the procedure. The fluorescein angio-

gram showed a minor increased granular transmission

in the early phase of the left eye that was no longer

visible in the late phase (Fig. 2), thus excluding RPE

window defects. The presence of a dark choroid could

Fig. 1 Fundus photographs

show good macular reflexes

of the right eye. Due to

patient’s unease during

photography they could

not be captured in the left

eye but were visible during

funduscopy

Fig. 2 Normal fluorescein

angiography with subtle

early transmission in the

early phase (upper left and

right, 560 0 resp. 780 0) that

was no longer visible in the

late phase (lower left and

right, 170 resp. 160 60 0)

92 Doc Ophthalmol (2008) 116:91–95

123

not be ruled out definitely. Goldmann perimetry was

performed to affirm intact peripheral visual fields and

detected a relative central scotoma with the I-2 target

within the central 10� in both eyes. It was found to

extend to 15� nasally in static perimetry (Octopus).

The Panel D-15 test showed several errors along the

protan axis and a red-green defect was found with the

Ishihara pseudoisochromatic test plates. The ISCEV

(International Society for Clinical Electrophysiology

of Vision [10]) scotopic and photopic full-field ERG

amplitudes (maximum flash intensity 2 cd s/m2) were

within the normal range (Fig. 3). However, the

multifocal ERG recorded according the ISCEV guide-

lines [11] revealed a reduction of the focal amplitudes

within the central 20� of the right eye and 15� of the left

eye (Fig. 4). Fundus autofluorescence recorded with a

standard confocal scanning laser ophthalmoscope

(Heidelberg Retina Angiograph, HRA, Heidelberg

Engineering, Heidelberg, Germany) was abnormal:

both eyes showed a slight circular parafoveolar

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Fig. 3 Full-field ERG

responses. Top: 2 9 4

traces: scotopic, below

the photopic condition with

30 cd/m2 background.

Bottom: flicker response,

enlarged averaged flicker

response (inset) and the

Fourier spectrum (spectral

magnitude [lV] vs.

frequency [Hz]). Repeat

traces are added for the rod,

cone and flicker responses

to demonstrate

reproducibility. The left eye

cone response replication

was not considered to be

of adequate quality. The

Fourier spectrum below the

flicker response corresponds

to the upper flicker trace.

Ignoring myographic

artifacts, this recording

is in the normal range

Doc Ophthalmol (2008) 116:91–95 93

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increase of AF (Fig. 5) surrounding a normal central

hypofluorescence. The patient was not available for

genetic testing.

Discussion

Our patient had an essentially normal funduscopy

given her dark pigmentation, normal rod and cone

responses in the full-field ERG and reduced central

responses in the multifocal ERG. The fluorescein

angiogram showed a subtle early transmission within

the normal range that was not detectable any more in

the late phase, thus excluding RPE defects. The

choroidal background fluorescence did not look like a

typical dark choroid, however we cannot exclude a

less pronounced form.

We found a pattern of slightly increased AF, only

a few degrees in diameter, encircling a normal foveal

hypofluorescence, symmetric between the eyes.

A similar small ring of central hyperfluorescence

has been found in early stages of other retinal

dystrophies such as SMD-FFM [12], X-linked cone-

rod dystrophy [13] and autosomal dominant cone-rod

dystrophy [14].

Lipofuscin accumulation in the retinal pigment

epithelium is considered the source of AF [15]. It is

thought to result mainly from rod photoreceptor outer

segment phagocytosis [16]. Elevated AF levels are

likely to result from an increased turnover of rod outer

segments [17], ineffective recycling activity of the

RPE [18] or insufficient phagocytosis [19]. Consider-

ing the first possibility, increased AF suggests

continuing metabolic activity from dysfunctional but

otherwise intact rods [20]. In our study, the extent of

abnormal AF comprised an approx. 5� diameter

whereas mfERG amplitudes reflecting only photopic

visual function were reduced within the central 15�–

20� in diameter. Thus, increased AF might hint at a

rod dysfunction additionally to cone dysfunction—as

5°

10°

20°

30°

100 ms

5°

10°

20°

30°

100 ms

Fig. 4 MfERG for a ±30�field. Circles indicate

eccentricity in 5�increments (traces are not

scaled to eccentricity but

equidistantly arranged for

better representation).

Central responses are

markedly reduced, normal

responses are seen above

15� of eccentricity

Fig. 5 Symmetric between

the eyes, fundus

autofluorescence

is increased encircling

the fovea

94 Doc Ophthalmol (2008) 116:91–95

123

demonstrated in the mfERG—that is not clinically

evident. Furthermore, in our case AF suggests that the

central RPE irregularities seen on funduscopy are not

only due to the dark pigmentation but represent a real

pathology, rendering the diagnosis of OMD doubtful.

Considering the fluorescein angiogram that bears

resemblance to a dark choroid, early SMD-FFM

becomes a likely diagnosis. Unfortunately, due to a

change of her place of residence to another country

the patient was not available for genetic testing.

However, in a case like hers mutation screening might

be the only way to establish a correct early diagnosis

when clinical findings do not point to one particular

diagnosis.

To conclude, the present case suggests that fundus

autofluorescence can be an additional useful tech-

nique to help diagnose a macular dystrophy in an early

stage and can already show pathologic changes when

fluorescein angiography results remain equivocal. As

findings may be unspecific among the different forms,

genetic testing should be considered to confirm the

clinical diagnosis.

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