Learning effect, hort-term fluctuation, and long-term fluctuation in frequency doubling technique

PURPOE: To evaluate hort-term and long-term fluctuation and learning effect in healthy ubject teted with the frequency doubling technique, which i baed on a low patial frequency and a high temporal frequency timulu. METHOD: Twenty-three healthy adult ubject were conecutively recruited from volunteer, and 20 ubject finihed the tudy. All the viual field were aeed by the frequency doubling technique, program C-20, full threhold. The frequency doubling technique preent timuli on a black-and-white video monitor with pecialized control circuitry interfaced to a microproceor. During program C-20, full threhold, 17 point are teted, one round point centrally and 16 quare one in the periphery up to 20 degree of eccentricity. Each timulu conit of a 0.25-cycle/degree inuoidal grating undergoing a 25-Hz counterphae flicker. One eye of each patient wa choen at random. Each ubject wa teted once in the firt eion, three time in the econd eion, and once in the third and fourth eion. Both hort-term and long-term fluctuation were tudied either a the average fluctuation value of all the point teted or a a point-to-point fluctuation. To tudy the learning effect, the reult of the firt eion were compared with thoe of the econd, the third, and the fourth eion. REULT: The average mean enitivity of the three examination of the econd eion wa 30.4 ± 1.24 dB, and the average hort-term fluctuation of all the ubject wa 2.16 ± 0.5 dB. The hort-term fluctuation of each point teted ranged from 1.4 to 3.4 dB. The average mean enitivity for all the eion wa 32.4 ± 1.14 dB, with an average long-term fluctuation of 3.23 ± 0.5 dB, and the long-term fluctuation of each teted point ranged from 2.5 to 4.4 dB. A mild learning effect wa found between the firt ection and the other. CONCLUION: hort-term and long-term fluctuation were imilar to thoe known to occur with the conventional threhold perimetry when they were compared with the literature data. A learning effect wa alo oberved and hould be taken into account for the clinical ue of thi tet.