Study: SITA Faster Can Diagnose and Monitor Glaucoma

Swedish Interactive Thresholding Algorithm (SITA) Faster (SFR) testing demonstrates little difference in the visual field (VF) parameters that SITA Standard (SS) can identify, according to a study published in the Journal of Glaucoma. The method can be used not only for screening, the study shows, but also for the diagnosis and follow-up of patients with glaucoma.

The researchers provided VF examinations with SS and SFR strategies between August 2018 and March 2019 on 169 eyes of 97 adult participants. When both of a subject’s eyes were eligible, the researchers randomly selected 1 eye. The 97 eyes included in the final analysis had glaucoma (47 with primary open-angle glaucoma (POAG), 15 with primary angle closure (PAC) glaucoma, 1 with steroid-induced glaucoma, 1 with PAC, 4 primary angle-close suspects (PACS) and 21 disc suspects. They all had best-corrected visual acuity of at least 20/40 and refractive error within plus or minus 5D of the sphere and plus or minus 3D of the cylinder. 

The subjects with glaucoma had glaucomatous optic neuropathy and compatible VF loss, and the subjects who were “glaucoma suspects” had occludable anterior chamber angles on gonioscopy or suspicious optic nerve heads. Subjects without glaucoma did not have a family history of glaucoma, had an internal ocular pressure (IOP) of 21 mm Hg or less, normal anterior segment, and normal appearance of the optic disc and fundus. This was the first VF test for about half of the subjects, the researchers noted.

All participants underwent both the SFR and SS examinations, which were all conducted on the same day. An SFR examination was issued first to 64 eyes. The researchers led a few subjects through a second SFR examination within the following month to assess test-retest variability. They eliminated the data of the 6 eyes that underwent SFR examinations with false-positive (FP) response of greater than15%. Those responses were independent of performing the VF test earlier (P =.89) and the order of the test strategy (P =.82).

Of the 97 eyes, 69 (71%) had the same Glaucoma Hemifield Test (GHT) classification in both tests, and median MD and visual field index (VFI) and overall average and sector-wise threshold sensitivities were similar between the tests. The exceptions were that nasal sector sensitivity was higher with SFR (26, P =.02) than with SS (25, P =.02), as was overall average sensitivity in eyes with more severe glaucoma. 

The test-retest variability for SFR was also low; the difference was -0.2 dB (95% LoA, -2.3 to 1.9) for MD and 1% (95% LoA, -4 to 6) for the VFI. The median test time was 374 seconds for SS and 169 seconds for SFR (P <.001), but the test time increased more (P <.05) per 1 dB of worse MD with SFR (3.3 seconds per dB) than with SS (1.6 seconds per dB). Pattern standard deviation (PSD) was worse with SS (4.8, P =.01) than with SFR (4.7, P =.01). 

A larger population of participants could have improved the study, the researchers said.

Disclosure: One of the study authors declared affiliations with relevant device manufacturers. Please see the original reference for a full list of disclosures.

Reference

Lavanya R, Riyazuddin M, Dasari S, et al. A comparison of the visual field parameters of SITA faster and SITA standard strategies in glaucoma. J Glaucoma. 2020;29(3):783–788. doi: 10.1097/IJG.0000000000001551