Comparison of Saccadic Vector Optokinetic Perimetry and Standard Automated Perimetry in Glaucoma. Part I: Threshold Values and Repeatability

Abstract

PurposeWe evaluated threshold saccadic vector optokinetic perimetry (SVOP) and compared results to standard automated perimetry (SAP).MethodsA cross-sectional study was done including 162 subjects (103 with glaucoma and 59 healthy subjects) recruited at a university hospital. All subjects underwent SAP and threshold SVOP. SVOP uses an eye tracker to monitor eye movement responses to stimuli and determines if stimuli have been perceived based on the vector of the gaze response. The test pattern used was equivalent to SAP 24-2 and stimuli were presented at Goldmann III. Average and pointwise sensitivity values obtained from both tests were compared using Pearson's correlation coefficient. Two versions of SVOP were evaluated.ResultsA total of 124 tests were performed with SAP and SVOP version 2. There was excellent agreement between mean threshold values obtained using SVOP and SAP (r = 0.95, P < 0.001). Excluding the blind spot, correlation between SVOP and SAP individual test point sensitivity ranged from 0.61 to 0.90, with 48 of 54 (89%) test points > 0.70. Overall SVOP showed good repeatability with a Pearson correlation of 0.88. The repeatability on a point-by-point basis ranged from 0.66 to 0.98, with 45 of 54 points (83%) > 0.80. Repeatability of SAP was 0.87, ranging from 0.69 to 0.96, with 47 of 54 (87%) points > 0.80.ConclusionEye-tracking perimetry is repeatable and compares well with the current gold standard of SAP. The technique has advantages over conventional perimetry and could be useful for evaluating glaucomatous visual field loss, particularly in patients who may struggle with conventional perimetry.Translational RelevanceSuprathreshold SVOP already is in the field. To our knowledge, this is the first report of threshold SVOP and provides a benchmark for future iterations.

Comparison of Threshold Saccadic Vector Optokinetic Perimetry (SVOP) and Standard Automated Perimetry (SAP) in Glaucoma. Part II: Patterns of Visual Field Loss and Acceptability

“…SVOP has some additional limitations, especially that the current display screen is unable to display stimuli brighter than 14 dB and that the current testing algorithm takes signficantly longer than SAP SITA Fast. 17 However, despite the longer test time, there was little difference in how the participants perceived the testing time, with most subjects scoring the time “just right” for both tests ( Fig. 4 ).…”

“…This finding also is supported by our separate analysis of agreement between SAP and SVOP threshold values, which found overall good agreement between these values, but poorer correlation between sensitivities in the central test locations. 17 However, it is possible that some cases of apparantly worse visual fields on SVOP compared to SAP were due to earlier detection of damage using SVOP.…”

“…The threshold SVOP device has been previously described. 17 Threshold SVOP consists of a personal computer with an examiner screen, a 24″ high-resolution LCD patient screen (Eizo ColorEdge CG243W) and an eye tracker (IS-1 model; Tobii Technology, Stockholm, Sweden; Fig. 1 ).…”

“…We recently developed a threshold SVOP test and have shown that threshold visual field sensitivities obtained using this device are correlated closely with SAP threshold values. 17 The ability to perform threshold visual field testing using an eye tracker has the potential to offer an alternative method of perimetry to those who struggle with conventional testing. In the present study we compared patterns of visual field loss detected by SAP and threshold SVOP and examined patient perceptions of each technique.…”

Reducing Spatial Uncertainty Through Attentional Cueing Improves Contrast Sensitivity in Regions of the Visual Field With Glaucomatous Defects

“… 70 Importantly, experiments measuring reaction time or signal detection may result in different attentional strategies, and hence results may not reflect exactly the same process. 72 Given the role of response/reaction time in conventional SAP 31 , 32 and the interest in reaction-time based perimetric tests, 73 it may be useful to study different cueing paradigms and experimental procedures for their implications in perimetric testing of patients with disease.…”