Abstract
Purpose :
To report on the prevalence and characteristics of (1) nonseeing retina that is not associated with a homogeneous dark appearance on fundus autofluorescence (FAF), and (2) seeing retina between the edge of the dense scotoma and the remote site used for eccentric fixation.
Methods :
25 participants (50 eyes) in the ProgStar Study at the Greater Baltimore Medical Center, who underwent reliable Nidek MP1 10-2 microperimetry and FAF imaging. Ten also had dense scotoma mapping perimetry (0dB only). We used MP1 software to measure distances in degrees. We compared findings of the baseline visit with the last visit available (24 months in 21, 18 months in 4).
Results :
(1) The dense scotoma corresponded to the homogeneously dark FAF lesion in 64%, and was larger than the lesion in 36%. When the dense scotoma exceeded the lesion, the nonseeing retina outside the lesion was mottled in 82%, uniform in 6%, and with only mild change in 12%. The nonseeing retina outside the lesion was indistinguishable from the more peripheral seeing retina. The linear extent of the dense scotoma outside the lesion was >10 deg in 6%, 5-10 deg in 71% and <5 deg in 24%.
(2) At baseline, fixation was central in 16% of eyes, at the border of (<=2 deg from) the dense scotoma in 18%, and was remote from the scotoma edge in 33 eyes (66%). For these eyes with remote fixation, the intervening retina not used for fixation had a linear extent of <5 deg in 13%, 5-7.5 deg in 71%, and >8 deg in 16% (2 could not be evaluated). The mean sensitivity in the intervening retina was >15 dB in 20%, 10-15 dB in 48%, 5-9 dB in 28% and <5 dB in 4%. The FAF character of the intervening retina was mottled in 52%, uniform in 30%, and mild change in 18%.
Conclusions :
The dense scotoma exceeded the central dark FAF lesion in 36% of eyes, and the FAF did not define the border of the dense scotoma. Fixation in patients with Stargardt disease was remote from the edge of the dense scotoma in 66% of eyes, despite intervening retina having good sensitivity, and this could not be explained on the basis of the FAF findings. FAF cannot be used alone to define nonseeing retina in many cases in Stargardt disease, and fixation location may be deceptive in terms of the true extent of the scotoma because in most cases it is remote from the edge of the scotoma.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.