Comparison of the Long-term and Short-term Fluctuations of Frequency-Doubling Technology Perimetry Between Peripheral and Paracentral Zones of Visual Field.

Abstract

To compare the long- and short-term fluctuations of frequency doubling technology perimetry between peripheral and paracentral zone and determine the relationship between threshold sensitivity and long- and short-term fluctuation within peripheral and paracentral zone of visual field. Descriptive study. Eye Department, United Nations, Pakistan Field Hospital Level-3 Darfur, Sudan, from February to July 2015. Normal eyes of 30 volunteers were recruited. Frequency doubling technology perimetry, program N-30, full threshold was employed. Each subject was tested at weekly intervals, once in the 1st, 3rd and 4th sessions and three times in the 2nd session. Visual field was divided into paracentral, superior, and inferior zones. Short-term and long-term fluctuation as well as threshold sensitivity were calculated for each patient as the mean fluctuation and mean sensitivity value. Mann-Whitney U-test was used to compare each zone in terms of their short- and long-term fluctuations and Spearman's rho correlation test for determining the relationship of threshold sensitivity with short- and long-term fluctuations. Long-term fluctuation values differences were insignificant between superior and paracentral zones. Short-term fluctuation values were statistically insignificant between all three zones. Short-term fluctuation and threshold sensitivity in each zone did not correlate. Long-term fluctuation and threshold sensitivity had a very weak negative, statistically insignificant correlation in superior and paracentral zones. Frequency doubling perimetry exhibits uniform short- and long-term fluctuations in peripheral and paracentral zones of visual field in normal subjects. Threshold sensitivity and long- and short-term fluctuations are independent of each other in peripheral and paracentral zones of visual field.