Comparison of Snellen acuity and objective assessment using the spatial frequency sweep PVER.
BACKGROUND
We compared the vision objectively assessed by spatial frequency sweep pattern-reversal visual-evoked response (SPVER) with the Snellen acuity in patients.


METHODS
SPVER acuity and Snellen acuity were measured in 100 patients with various ocular pathologies, including macular diseases, diffuse retinal degeneration, optic nerve diseases, glaucoma, and high myopia. For SPVER, 10 sinusoidally modulated vertical gratings were presented as stimuli. The responses were averaged and displayed through the discrete Fourier transform on the monitor display. The PVER acuity was determined by extrapolating the SPVER amplitude-spatial frequency function to baseline.


RESULTS
Vision ranged from 20/15 to 20/400 with Snellen acuity, and from 20/25 to 20/190 with SPVER. The overall correlation between the two acuities was r = 0.666. The correlation varied from r = 0.895 in eyes with glaucoma to r = 0.436 in eyes with optic nerve disease. Seventy-seven eyes (77%) had a visual acuity agreement of within 1.0 octave between the two measurements.


CONCLUSIONS
The SPVER acuity and the Snellen acuity correlated to a certain degree. Discrepancies were found in certain diseases, with the highest disparity in patients with optic nerve disease. We conclude that the SPVER is effective in estimating vision objectively, particularly in patients in whom the standard Snellen test is impossible to perform or yields unreliable results.
Arai
M
M
Schepens Eye Research Institute, Boston, MA 02114, USA.
Katsumi
O
O
Paranhos
F R
FR
Lopes De Faria
J M
JM
Hirose
T
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005128:Eye Diseases / Q000503:physiopathology*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D014792:Visual Acuity / Q000502:physiology*