Purpose:
Stargardt’s disease is a juvenile macular degeneration that is produced by mutations in the ABCA4 gene, resulting in visual impairment in the central visual field. The purpose of this investigation was to evaluate the efficacy of the Heidelberg Edge Perimeter (HEP) for quantifying central visual field loss.
Methods:
Forty one eyes of thirty patients with molecularly confirmed ABCA4-associated Stargardt disease were evaluated with the Heidelberg Edge Perimeter (HEP). The HEP performs perimetric testing, using flicker-defined form as stimuli. Each patient also received a thorough retinal ophthalmologic examination and kinetic testing on the Goldmann perimeter. All patients had undergone prior ophthalmic examinations, visual field and other visual function tests.
Results:
HEP mean deviation (MD) values ranged between 0.13 and -20.98 dB (mean = -10.33 dB, sd = 6.473 dB), and pattern standard deviation (PSD) values ranged between 1.18 and 5.75 dB (mean = 3.612 dB, sd = 1.266 dB). Testing time ranged between 2.95 and 11.15 minutes (mean = 7.558 minutes, sd = 1.667 minutes). The figures show the distribution of MD values for different testing times (r = .49) on the top left, the distribution of PSD values for different testing times (r = .60) on the top right, the relationship between MD and LOGMAR visual acuity (r = .72 ) on the bottom left and PSD and LOGMAR visual acuity ( r = .55 ) on the bottom right. For each graph the relationships were fitted by a second order polynomial, which provided a better fit than a linear relationship in all cases. Comparison of HEP results with the central visual field obtained by kinetic testing on the Goldmann perimeter revealed good agreement.
Conclusions:
Flicker-defined form, as determined by the HEP, is able to characterize the extent of central visual field loss in Stargardt’s disease and is capable of quantitatively staging the amount of damage. Future extensions of this work will focus on the ability of the HEP to evaluate progressive visual loss in this patient population in an effort to distinguish fast versus slow progression and relate this functional information to variations in the alleles that are identified through genetic assessment.
Keywords: perimetry • visual fields • genetics