The Usefulness of Gaze Tracking as an Index of Visual Field Reliability in Glaucoma Patients.

PURPOSE

We evaluated the usefulness of gaze tracking (GT) results as an index of visual field reliability in glaucoma.

METHODS

The study population consisted of 631 eyes of 400 patients with open angle glaucoma in an institutional practice, with 10 visual fields (VFs). For the observational procedure, visual fixation was assessed using the gaze fixation chart at the bottom of the VF (Humphrey Field Analyzer, 30-2 SITA standard) printout. Average frequency of eye movement between 1° and 2° (move(1-2)), 3° and 5° (move(3-5)), and greater than or equal to 6° (move(≥6)) were calculated. In addition, average tracking failure frequency (TFF) and average blinking frequency (BF) were calculated. The relationship between mean deviation (MD), fixation losses (FLs), false-positives (FPs), false-negatives (FNs), move(1-2), move(3-5), move(≥6), TFF, BF, and pattern standard deviation (PSD) were evaluated using linear modeling. Main outcome measures included parameters related to over- or underestimation of MD values.

RESULTS

Patients' mean MD progression rate was -0.23 dB/y. The best model to predict MD values included FL rate, FP rate, move(3-5), move(≥6), TFF, BF, and PSD as dependent variables with coefficients of 0.90, 9.2, -0.57, -0.52, -2.2, -1.1, and -0.56, respectively (P < 0.001).

CONCLUSIONS

High FL and FP rates tend to raise MD values. By contrast, high values of move(3-5), move(≥6), TFF, BF, and PSD tend to lower MD values. Thus, GT parameters can be used as new indices of VF reliability through the prediction of over- or underestimation of VF results.