Purpose:
To analyze on a long term basis microperimetry, standard short-wavelenght (SW-FAF) and near infrared-wavelenght fundus autofluorescent (NIR-FAF) changes in eyes with geographic atrophy (GA) secondary to age-related macular degeneration.
Methods:
Fourteen consecutive patients (20 eyes) affected by GA were studied by means of microperimetry to assess fixation and retinal sensitivity changes every six months during follow-up. All patients performed SW-FAF and NIR-FAF at any follow-up visit.
Results:
Mean follow-up was 12.26 ± 4.45 months. Total hypoFAF area was always significantly wider in NIR-FAF than in SW-FAF (5.05 ± 2.40 mm2 vs 4.45 ±± 2.41 mm2, p=0.012 at baseline; 5.78 ±2.87 mm2 vs 5.21 ± 2.77 mm2, p<0.0001 at last follow-up visit). The mean GA enlargement was +0.76 ± 1.24 mm2/year in SW-FAF and +0.92 ±1.10 mm2/year in NIR-FAF. Mean retinal sensitivity significantly decreased from 7.79 ± 4.02 dB to 6.76 ± 4.50 dB (p=0.006). 47.3% of the relative dense scotoma (≤ 5 dB) tested points at baseline evolved to absolute scotoma. Relative scotomata characterized by hypoSW-FAF or hyperNIR-FAF had a higher risk of evolving to absolute scotoma respectively than normo- and hyper-FAF in SW-FAF (O.R.=2.70 and O.R.=2.68, respectively), and normo- and hypo-FAF in NIR-FAF (O.R.=3.20 and O.R.=2.17 respectively).
Conclusions:
SW-FAF, compared to NIR-FAF, may underestimate the baseline extension and progression of GA. Different FAF patterns, assessed by SW-FAF and NIR-FAF, have different relative risk of GA progression. SW-FAF should be integrated with NIR-FAF in the follow-up of GA from both a morphological and functional perspective.
Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • perimetry