Evaluation of the Performance of Algorithm-Based Methods for Subjective Refraction

Abstract

Objective: To evaluate the performance of two subjective refraction measurement algorithms by comparing the refraction values, visual acuity, and the time taken by the algorithms with the standard subjective refraction (SSR). Methods: The SSR and two semi-automated algorithm-based subjective refraction (SR1 and SR2) in-built in the Vision-R 800 phoropter were performed in 68 subjects. In SR1 and SR2, the subject’s responses were recorded in the algorithm which continuously modified the spherical and cylindrical component accordingly. The main difference between SR1 and SR2 is the use of an initial fogging step in SR1. Results: The average difference and agreement limits intervals in the spherical equivalent between each refraction method were smaller than 0.25 D, and 2.00 D, respectively. For the cylindrical components, the average difference was almost zero and the agreement limits interval was less than 0.50 D. The visual acuities were not significantly different among the methods. The times taken for SR1 and SR2 were significantly shorter, and SR2 was on average was three times faster than SSR. Conclusions: The refraction values and the visual acuity obtained with the standard subjective refraction and algorithm-based methods were similar on average. The algorithm-based methods were significantly faster than the standard method.

Subjective refraction using power vectors by updating a conventional phoropter with a Stokes lens for continuous astigmatic power generation

“…For that purpose, we developed and validated 22 a set of three continuously variable Stokes lenses with three different powers, ranging from 0.00 to ±0.75, ±1.25 and ±1.75 D. This is not the first attempt to develop new methodologies for the direct measurement of power vector components in monocular refraction and to compare the findings with standard subjective routines. In that sense, repeatability as well as efficiency, precision and accuracy of directly manipulating the power vectors have been reported for the HVA in the late 1970s/early 1980s, 26‐28 a novel clinical refractor introduced by Raasch in the 2000s 29 and a phoropter introduced by Essilor (Vision‐R 800; essilorusa.com) incorporating tunable lenses for continuous variation of the spherical and cylindrical powers 30 . However, we present here an intermediate solution which is cost‐effective (thus ameliorating one of the drawbacks of the HVA as well as the complex power vector phoropters such as the Vision‐R 800) while providing similar results in comparison with standard monocular subjective refraction.…”

“…In that sense, repeatability as well as efficiency, precision and accuracy of directly manipulating the power vectors have been reported for the HVA in the late 1970s/early 1980s, [26][27][28] a novel clinical refractor introduced by Raasch in the 2000s 29 and a phoropter introduced by Essilor (Vision-R 800; essilorusa.com) incorporating tunable lenses for continuous variation of the spherical and cylindrical powers. 30 However, we present here an intermediate solution which is cost-effective (thus ameliorating one of the drawbacks of the HVA as well as the complex power vector phoropters such as the Vision-R 800) while providing similar results in comparison with standard subjective refraction. Moreover, we describing the full step-by-step methodology (something hidden in previous work) while providing an exhaustive statistical analysis from the obtained results.…”

Beyond traditional subjective refraction

“…Venkataram et al. [7 ▪ ] compared this instrument with two different algorithms (one used fogging, the other did not) with the traditional subjective refraction. They found no statistically significant differences in spherical equivalent and the mean deviation was 0.0D [Limits of Agreement (LOAs): [−0.80, +0.80]D] with fogging, and -0.20D (LOAs: [−1.00, +0.60]D) without fogging.…”

“…Subjective refraction is time-consuming. It entails, for each patient's eye, the full dedication of a well trained eye care professional for more than 6 min on average [3][4][5][6]7 & ], and can be much more in some patients. Subjective refraction represents, for many eye care practitioners, a considerable portion of every workday.…”

Implementation of Kiosk-Type System Based on Gaze Tracking for Objective Visual Function Examination

“…Subjective examination is conducted through the examinee's feedback. When the examiner asks a question while the examination is in progress, the examinee answers the question [5][6][7]. This is also known as a subjective examination, and in actual clinical practice, it is treated as an important examination because it is necessary to consider how clear the examinee wants to see and the feeling of wearing, such as dizziness and comfort.…”