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“Fairly good agreement” was found between the threshold sensitivities of a novel, smartphone-based, head-mounted perimeter and Humphrey field analyzers (HFA), with most patients studied preferring the smartphone-based perimeter. The device may supplement HFA “as a portable or home perimeter,” according to a study published in the Journal of Glaucoma.
The prospective, cross-sectional study looked at 107 eyes (34 with glaucoma, 18 glaucoma suspects, and 55 without glaucoma) of 54 participants who underwent HFA and the novel GearVision (GV) perimeter device in random order and then completed a questionnaire about their experiences. A total of 84 eyes with reliable HFA and GV results were used in the final analysis. The main outcome measure was the agreement of threshold sensitivities using Bland and Altman analysis.
The median false-positive response rate for GV was 7% (4% to 12%), and for HVA was 0% (0% to 6%, P <.001). Median false-negative response rate was similar for both tests. The median threshold sensitivity of all 52 points on HFA was 29.1 dB (26.5 to 30.7 dB) and for GV was 30.6 dB (29.1 to 32.6 dB; P <.001).
Researchers found that the agreement between the GV and HFA devices for total threshold sensitivity was a mean difference of -1.9 dB (95% limits of agreement -5 to 1) — and the GV device was the preferred perimeter in 68.2% of participants if repeat perimetry was required, compared with HFA (20.6%, P <.001).
The investigators speculate that this technology could have a number of applications, such as for patients who struggle with mobility or for whom in-person clinic visits are a barrier to care. “It could also be used in physically healthy individuals who live in remote areas where transport to tertiary eye care centers is difficult,” researchers explain. “Another potential use which is unique to this device is ‘home perimetry.’ This is because most other portable devices are gadgets that can be used for perimetry alone and are still too expensive for individual purchase. GV is essentially a smartphone app and the only additional hardware required is the GearVR HMD,” which researchers say costs approximately $107.00.
The study’s main limitation was the fact that it compared the GV perimetry system with the HFA full-threshold strategy — but that’s mostly been replaced by the Swedish Interactive Thresholding Algorithm (SITA) strategies in clinical practice, according to investigators.
“This was done as the current GV program utilizes the 4-2 bracketing strategy to determine threshold sensitivities which is similar to the HFA full-threshold test,” the report explains. “SITA strategy models are based on distributions of normal threshold levels obtained using the original full-threshold program. Therefore, this is the indispensable first step in the evolving GV technology and the encouraging initial results will allow us to generate a normative database.”.
Another limitation was inclusion of both eyes per patient, and because the number of eyes in each subgroup was small, they didn’t perform a subgroup analysis.
Disclosure: One study author declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Reference
Pradhan ZS, Sircar T, Agrawal H, et al. Comparison of the performance of a novel, smartphone-based, head-mounted perimeter (gearvision) with the humphrey field analyzer. J Glaucoma. 2021;30(4):e146-e152. doi:10.1097/IJG.0000000000001797.
