Abstract
Purpose::
To evaluate the relationship among visual acuity, reading acuity, contrast sensitivity(CS) and multifocal electroretinogram (mfERG) in patients with cone dystrophy (CD) or with occult macular dystrophy (OMD).
Methods::
In eighteen eyes in nine patients with CD and twelve eyes with six patients with OMD, we measured the best-corrected far vision acuity (VA). MfERG was recorded at 103 discrete retinal locations using VERIS (Mayo, Japan) and the critical print size (CPS) was determined with the Japanese version of Minnesota reading chart (MNREAD-J Chart). CS was examined by using CA2000 (Neits, Japan).
Results::
The mfERG implicit times of responses from central 10 degree area, were delayed 1.4msec in CD and 1.2msec in OMD consequently comparing to those from the peripheral area. VA(log MAR) was CD: 0.51+/- 0.12 , OMD: 0.27+/- 0.13. CPS(log MAR) was CD: 0.56+/-0.27, OMD: 0.56+/- 0.09. CS decreased more remarkably at day vision in comparison with night vision on patients with both CD and OMD. In eyes with CD the correlations between VA and CS showed statistically significant (R=0.723, p= 0.004), but the correlations between VA and CS, VA and CS did not reached statistical significance in OMD.
Conclusions::
The visual impairment was revealed by mfERG, CS and reading acuity reveals as same degree in both CD and OMD, however independent of VA. In eyes with OMD, CS and CPS bore no consistent relationship to VA. Eyes with OMD showed severer visual dysfunction than expected from VA.
Keywords: electroretinography: clinical • degenerations/dystrophies • reading