Sensitivity and Specifictity of Frequency Doubling Perimetry Program N-30

Charoenchai Jewjinda, M.D.,
Paisan Sahapattan, M.D.,
Prin Rojanapongpun, M.D.

ABSTRACT : Purpose : To determine sensitivity and specificity of frequency doubling perimetry (FDP) full threshold program N-30 using Humphrey Field Analyzer (HFA) as a gold standard.
Design : Cross sectional descriptive study
Methods : Data were obtained from right eyes of 24 normal subjects and 24 glaucomatous eyes with advanced field loss. A comprehensive ocular examination as well as HFA program 24-2 SITA-standard, FDP full threshold N-30 and Heidelberg retina tomography (HRT-II)
Results : Of 24 eyes classified as glaucoma, 100% (24/24) were abnormal on FDP when used at least 1 missed point criteria while 95.8% (23/24) were abnormal on FDP when used two or more missed points criteria. Of 24 eyes classified as normal, FDP reported 41.66% (10/24) as normal using at least 1 missed point criteria and 58.33% (14/24) using two or more missed points criteria. The means test time of FDP N-30 and HFA in normal group were 4.99 ? 0.36 vs 5.05 ? 0.79 minutes (p = 0.52). In advanced glaucoma group, FDP test time of 5.13 ? 0.37 was significantly less than HFA test time of 6.59 ? 1.65 minutes (p = 0.007).
Conclusions : FDP threshold test N-30 has a high sensitivity in detecting functional loss in advanced glaucoma cases but has a low specificity when we use HFA as a gold standard. The FDP test time is shorter than HFA in advanced glaucoma cases.

Thai J Ophthalmol 2002 ; January-June 16(1) : 63-69.