The association between ocular surface measurements with visual field reliability indices and gaze tracking results in preperimetric glaucoma

Background/aimsTo investigate the relationship between gaze tracking (GT) results and ocular surface condition in glaucoma.MethodThe Humphrey 24–2 visual field (VF) was measured in 34 eyes of 30 patients with open-angle glaucoma without VF damage. Tear break-up time, Schirmer’s test, tear meniscus volume (TMV) and presence of superficial punctate keratopathy (SPK) were also measured in order to describe the condition of the ocular surface. Various GT parameters were calculated: the average frequency of eye movements per stimulus between 1° and 2° (move1-2), the average frequency of eye movements per stimulus between 3° and 5° (move3-5), the average frequency of eye movements per stimulus more than 6° (move≥6), the average tracking failure frequency per stimulus (TFF) and the average blinking frequency. The relationship between GT parameters, reliability indices and ocular surface measurements was investigated using linear mixed modelling.ResultsSPK was positively associated with high rates of move3-5(coefficient=0.12 for SPK+, p=0.003) and move≥6(coefficient=0.052 for SPK+, p=0.023). High TMV was significantly related to TFF (coefficient=0.37, p=0.023). Fixation losses, false-positives and false-negatives were not significantly associated with any GT parameters or ocular surface measurements.ConclusionSPK is associated with increased frequency of eye movements (move3-5and move≥6). In addition, large TMV is associated with increased rate of TFF. Careful attention should be paid when interpreting GT parameters in patients with SPK or a large TMV.