Purpose. To determine whether critical flicker/fusion (CFF) thresholds fulfill the criteria for a potential vision test (PVT) by being unaffected by media opacity yet affected by retinal disease.

Methods. CFF thresholds for three different stimulus sizes (0.5, 1.0, and 1.5°) were measured in 72 patients (mean age, 78.43 ± 7.07 years) comprising 31 subjects with media opacity, 21 with macular disease, and 20 with pseudophakia.

Results. There were no statistically significant differences between CFF values from the media opacity and the pseudophakia groups for any target size (p > 0.10). However, CFF values were significantly lower in patients with macular disease for all the target sizes (p < 0.05). Analysis of a subset of six subjects with media opacity and seven subjects with macular disease and visual acuity of 20/200 or worse showed the media opacity group still had similar CFF values as the pseudophakia group and had significantly higher CFF than the macular disease group.

Conclusions. CFF testing is shown to fulfill the requirements for a PVT and may prove to be particularly useful for patients with dense media opacity. (Optom Vis Sci 2004;81:905-910)

Key words: critical flicker/fusion frequency, media opacity, age-related macular degeneration (ARMD), potential vision test

Optometry and Vision Science, Vol. 81, No. 12, December 2004
Submitted for publication November 6, 2003; accepted October 4, 2004.

MARTA VIANYA-ESTOPÀ, MSc
WILLIAM A. DOUTHWAITE, PhD
KONRAD PESUDOVS, PhD, FAAO
BRUCE A. NOBLE, MB, BS
and DAVID B. ELLIOTT, PhD, FAAO
Department of Optometry, University of Bradford, Bradford, West Yorkshire, United Kingdom (MVE, WAD, KP, DBE), and
Department of Ophthalmology, Leeds General Infirmary, Clarendon Wing,
Belmont Grove, Leeds, West Yorkshire, United Kingdom (BAN)