Introduction: Phoropters are widely accepted for clinical use in refraction examination and visual function assessment. This study assessed the reliability of the new Inspection Platform of Visual Function (IPVF) in comparison with the conventional equipment phoropter (TOPCON VT-10) in visual function assessment.
Methods: This prospective study enrolled 80 eyes of 80 healthy subjects. The horizontal phoria at distance and near (Phoria_D and Phoria_N, respectively) was measured with the von Graefe method, negative/positive relative accommodation (NRA/PRA) was measured with the positive/negative lens method, and accommodative amplitude (AMP) was measured with the minus lens method. Data of three consecutive measurements with each instrument were evaluated using the intraclass correlation coefficient (ICC) for repeatability, and the agreement of the two instruments was evaluated using a Bland-Altman plot.
Results: The ICCs of the three consecutive measurements for phoria, NRA/PRA, and AMP using the IPVF instrument were high (0.87-0.96), indicating high repeatability. The ICCs of the three consecutive measurements using the phoropter were high (0.914-0.983) for phoria, NRA, and AMP, indicating high repeatability, while that of PRA was 0.732 (between 0.4 and 0.75), indicating acceptable repeatability. The 95% limits of agreement of phoria, NRA/PRA, and AMP were narrow, indicating good agreement between the two instruments.
Conclusion: The repeatability of both instruments was high, and the IPVF instrument was slightly better in terms of PRA repeatability than the phoropter. The agreement of phoria, NRA/PRA, and AMP measured by the new IPVF instrument and phoropter was also satisfactory.
Keywords: Accommodative amplitude; Agreement; NRA/PRA; Phoria; Repeatability.
Nonstrabismic binocular dysfunctions (NBD) are common vision abnormalities. The relevant indicators involved in NBD are accommodative anomalies, convergence and divergence anomalies, and phoria. Convergence and divergence anomalies are disorders of binocular vision that result in either a failure of fusion or an inability to accurately integrate and stabilize retinal images from both eyes into a single representation. Phoria is the tendency of the eyes not to be directed towards the point of fixation, manifested in the absence or prevention of fusion. Measurement of accommodation and phoria are two particularly important components of comprehensive eye examination. Phoropter is widely used in ophthalmic clinics and optical stores for refraction examination and visual function assessment. It largely depends on the examiner’s training, skill, and experience, which leads to high inter-examiner variability. In large-scale eye screening or busy hospital hours, examinees have to be inspected one by one using traditional instruments, which can be time consuming and tiring for optometrists, and can cause long queuing time for examinees. In this study, we evaluated the possibility of an alternative automatic diagnostic instrument for the assessment of binocular visual function. The platform is a new type of intelligent visual function inspection equipment with good reliability, and could be an alternative for clinicians to obtain visual function measurements with improved efficiency and fewer subjective errors. The use of this automatic instrument can avoid inter-examiner variability, helping to resolve the shortage problem of optometrists in China and offer a better testing service to eye examinees.
© 2023. The Author(s).