Purpose: To investigate the effect of cataract extraction on the results of frequency doubling technology (FDT) perimetry in healthy subjects.
Design: Single-center, prospective, case series.
Methods: We performed FDT threshold C20-1 and Humphrey Swedish Interactive Threshold Algorithm (SITA)-fast programs within 1 month before and 2 months after phacoemulsification in 52 consecutive nonglaucomatous patients. Global indexes, including mean deviation and mean sensitivity of FDT and mean deviation of SITA-fast, were compared before and after cataract surgery. Mean sensitivity of FDT at various visual field grid locations was also compared before and after cataract surgery, as were localized indexes of both FDT and SITA-fast.
Results: Mean deviation improved after cataract surgery in both FDT threshold (from -7.09 dB--2.16 dB) and SITA-fast program (from -6.14 dB--2.87 dB). The mean sensitivity at 17 grid locations when the FDT threshold program was used significantly improved postoperatively (from 19.6 dB-26.13 dB). Postoperative improvements in mean sensitivity were also significant at all different sectors, but there were no significant differences of improvement among them. Postoperative pattern standard deviations from FDT and SITA-fast did not differ significantly from their preoperative values.
Conclusions: Cataracts induced a generalized reduction of sensitivity in FDT threshold as well as SITA-fast perimetry. Cataract removal did not change pattern standard deviation of FDT or of SITA-fast. Caution should be taken when interpreting the results of FDT perimetry in the eyes with cataract.