Ametropia detection using a novel, compact wavefront autorefractor.

Introduction: Despite the well-known reproducibility issues of subjective refraction, most studies evaluating autorefractors compared differences between the device and subjective refraction. This work evaluated the performance of a novel handheld Hartmann-Shack-based autorefractor using an alternative protocol, which considered the inherent variability of subjective refraction.

Methods: Participants underwent an initial measurement with a desktop autorefractor, two subjective refractions (SR1 and SR2) and a final measurement with the QuickSee Free (QSFree) portable autorefractor.

Correction: Assesment of the QuickSee wavefront autorefractor for characterizing refractive errors in school-age children.

[This corrects the article DOI: 10.1371/journal.pone.

Prediction of manifest refraction using machine learning ensemble models on wavefront aberrometry data.

Purpose: To assess the performance of machine learning (ML) ensemble models for predicting patient subjective refraction (SR) using demographic factors, wavefront aberrometry data, and measurement quality related metrics taken with a low-cost portable autorefractor.

Methods: Four ensemble models were evaluated for predicting individual power vectors (M, J, and J) corresponding to the eyeglass prescription of each patient. Those models were random forest regressor (RF), gradient boosting regressor (GB), extreme gradient boosting regressor (XGB), and a custom assembly model (ASB) that averages the first three models.

Predicting subjective refraction with dynamic retinal image quality analysis.

The aim of this work is to evaluate the performance of a novel algorithm that combines dynamic wavefront aberrometry data and descriptors of the retinal image quality from objective autorefractor measurements to predict subjective refraction. We conducted a retrospective study of the prediction accuracy and precision of the novel algorithm compared to standard search-based retinal image quality optimization algorithms. Dynamic measurements from 34 adult patients were taken with a handheld wavefront autorefractor and static data was obtained with a high-end desktop wavefront aberrometer.

Investigation of the Accuracy of a Low-Cost, Portable Autorefractor to Provide Well-Tolerated Eyeglass Prescriptions: A Randomized Crossover Trial.

Purpose: To compare patient preferences for eyeglasses prescribed using a low-cost, portable wavefront autorefractor versus standard subjective refraction (SR).

Design: Randomized, cross-over clinical trial.

Participants: Patients aged 18 to 40 years presenting with refractive errors (REs) to a tertiary eye hospital in Southern India.

Assesment of the QuickSee wavefront autorefractor for characterizing refractive errors in school-age children.

Purpose: To assess the performance of an open-view binocular handheld aberrometer (QuickSee) for diagnosing refractive errors in children.

Methods: 123 school-age children (9.9 ± 3.

Beneficial effects of paricalcitol on cardiac dysfunction and remodelling in a model of established heart failure.

Background And Purpose: The synthetic vitamin D3 analogue paricalcitol acts as a selective activator of the vitamin D receptor (VDR). While there is evidence for cardioprotective effects of paricalcitol associated with the VDR pathway, less information is available about the structural and functional cardiac effects of paricalcitol on established heart failure (HF) and particularly its effects on associated electrophysiological or Ca handling remodelling.

Experimental Approach: We used a murine model of transverse aortic constriction (TAC) to study the effect of paricalcitol on established HF.

Validation of an Affordable Handheld Wavefront Autorefractor.

Significance: There is a critical need for tools that increase the accessibility of eye care to address the most common cause of vision impairment: uncorrected refractive errors. This work assesses the performance of an affordable autorefractor, which could help reduce the burden of this health care problem in low-resource communities.

Purpose: The purpose of this study was to validate the commercial version of a portable wavefront autorefractor for measuring refractive errors.

Quality of eyeglass prescriptions from a low-cost wavefront autorefractor evaluated in rural India: results of a 708-participant field study.

Objective: To assess the quality of eyeglass prescriptions provided by an affordable wavefront autorefractor operated by a minimally trained technician in a low-resource setting.

Methods And Analysis: 708 participants were recruited from consecutive patients registered for routine eye examinations at Aravind Eye Hospital in Madurai, India, or an affiliated rural satellite vision centre. Visual acuity (VA) and patient preference were compared between trial lenses set to two eyeglass prescriptions from (1) a novel wavefront autorefractor and (2) subjective refraction by an experienced refractionist.

Tunable lenses: dynamic characterization and fine-tuned control for high-speed applications.

Tunable lenses are becoming ubiquitous, in applications including microscopy, optical coherence tomography, computer vision, quality control, and presbyopic corrections. Many applications require an accurate control of the optical power of the lens in response to a time-dependent input waveform. We present a fast focimeter (3.

Design and Clinical Evaluation of a Handheld Wavefront Autorefractor.

Purpose: To introduce a novel autorefractor design that is intended to be manufacturable at low cost and evaluate its performance in measuring refractive errors.

Methods: We developed a handheld, open-view autorefractor (the "QuickSee" [QS]) that uses a simplified approach to wavefront sensing that forgoes moving parts and expensive components. Adult subjects (n = 41) were recruited to undergo noncycloplegic refraction with three methods: (1) a QS prototype, (2) a Grand Seiko WR-5100K (GS) autorefractor, and (3) subjective refraction (SR).

Recovery and normalization of triple coincidences in PET.

Purpose: Triple coincidences in positron emission tomography (PET) are events in which three γ-rays are detected simultaneously. These events, though potentially useful for enhancing the sensitivity of PET scanners, are discarded or processed without special consideration in current systems, because there is not a clear criterion for assigning them to a unique line-of-response (LOR). Methods proposed for recovering such events usually rely on the use of highly specialized detection systems, hampering general adoption, and/or are based on Compton-scatter kinematics and, consequently, are limited in accuracy by the energy resolution of standard PET detectors.

NEMA NU 4-2008 comparison of preclinical PET imaging systems.

Unlabelled: The National Electrical Manufacturers Association (NEMA) standard NU 4-2008 for performance measurements of small-animal tomographs was recently published. Before this standard, there were no standard testing procedures for preclinical PET systems, and manufacturers could not provide clear specifications similar to those available for clinical systems under NEMA NU 2-1994 and 2-2001. Consequently, performance evaluation papers used methods that were modified ad hoc from the clinical PET NEMA standard, thus making comparisons between systems difficult.