Comparison of Matrix and SITA in Patients With Glaucoma

Abstract

Purpose: : To compare measurements obtained by the Swedish interactive threshold algorithm (SITA) and Humphrey Matrix (Matrix) in patients with glaucoma.

Methods: : Subjects consisted of 30 patients with 50 eyes in early glaucoma having a mean deviation (MD) better than –3.0D as measured by SITA. Perimetries were performed using SITA standard 24–2 and Matrix 24–2 threshold programs. Measurements taken with SITA and Matrix were performed within 3 months of each other. In this study, we analyzed results of the glaucoma hemifield test (GHT), the MD, the pattern standard deviation (PSD), the number of measurement points of pattern deviation (PD) whose p value was less than 0.05, and the number of clusters. Furthermore, the incidence rate of glaucomatous visual field loss, as measured by SITA and Matrix, was compared. The minimal criteria for glaucomatous visual field loss was defined as follows: SITA and Matrix results "outside normal limits," or PSD probability above the normal upper 5^th percentile, or when there were three or more clustered locations present on the pattern deviation probability plot with a p value of 0.05 or greater.

Results: : GHT was outside normal limits in 10 eyes as measured by Matrix and 2 with SITA (P<0.01). MD was –1.83+/– –2.59D and –0.19+/– –1.08D, and PSD was 2.83+/– 0.45D and 1.86+/– 0.43D as measured with Matrix and SITA, respectively (p<0.01). The number of measurement points at a p value of less than 0.05 were 4.3+/–3.5 and 5.3+/–4.2 (p=0.35), and the number of clusters were 1.5+/–2.2 and 2.5+/–3.0 (p=0.053) as measured by Matrix and SITA, respectively. There was no significant difference in the incidence rate of glaucomatous visual field loss when measured by Matrix (30%) or SITA (24%). According to the criteria of each test, GHT was 20% and 4% (p<0.01), PSD was 16% and 2% (p<0.01), and the number of clusters was 14% and 24% (p>0.05) as measured by Matrix and SITA, respectively. Using SITA, patients’ determination of visual field loss tended to be based on the number of clusters present.

Conclusions: : It is important to note that under Matrix, eyes were judged to have visual field loss based on GHT results and a high PSD value, whereas under SITA, the number of clusters was the determining factor in many cases.

Keywords: visual fields • clinical (human) or epidemiologic studies: outcomes/complications • perimetry