Journal: BMJ Open Ophthalmology

Article Title: Comparison of the Near Eye Tool for Refractive Assessment (NETRA) and non-cycloplegic subjective refraction

doi: 10.1136/bmjophth-2021-000851

Figure Lengend Snippet: Bland-Altman plots of means versus differences for NETRA (Near Eye Tool for Refractive Assessment) after cycloplegia and subjective refraction (SR) for 34 right (first column) and left eyes (second column). Parts (A) and (B) are the Bland-Altman plots for the stigmatic ( F I = M ) coefficients, part (C) and (D) the ortho-antistigmatic ( F J = J 0 ) coefficients and part (E) and (F) the oblique-antistigmatic ( F k = J 45 ) coefficients of power, respectively, for the right and left eyes. Note the differences in scales in the different parts.

Article Snippet: Scientists at the Massachusetts Institute of Technology and the company EyeNetra (USA) created the NETRA (Near Eye Tool for Refractive Assessment), a smartphone-based refractive tool that requires minimal training and which incorporates both objective and subjective refractive techniques for self-evaluation of refractive error.

Techniques:

Journal: BMJ Open Ophthalmology

Article Title: Comparison of the Near Eye Tool for Refractive Assessment (NETRA) and non-cycloplegic subjective refraction

doi: 10.1136/bmjophth-2021-000851

Figure Lengend Snippet: (A) The NETRA (Near Eye Tool for Refractive Assessment) device consists of a plastic-moulded binocular fixation system, with centration and alignment knobs, a confirmation of alignment button and an Android application that operates on the Samsung Galaxy S4 smartphone. The fixation system houses a microlens (pinhole) array and positive-powered optical lenses (to relax ocular accommodation) placed in front of the smartphone LCD display. In part (B), an illustration shows an inverse of the Shack-Hartmann technique whereby the NETRA replaces the sensor (in a wavefront aberrometer) with a LCD display on a smartphone and asks the subject to align Vernier lines seen on the smartphone screen. The NETRA target as seen by a user is shown in part (Ci). The interactive software displays two umbrellas on the phone screen and the handles of the umbrellas are aligned by the participant (Cii). When alignment occurs, the user confirms by pressing the appropriate button on the device. Part (D) is an illustration of the NETRA setup in a schematic eye (optical system). An emmetropic eye converges parallel rays onto point P on the retina. A myopic eye focuses light at a point before the retina, delivering two points (P A and P B ) to the retina. By moving focuses A and B closer to each other on the show plane, the resulting rays focus at point P on the retina. The amount of shift required from A to Aˈ and B to Bˈ is used in the NETRA to calculate the refractive error. The quantity t is the distance from the pinhole array to the eye, while a is the spacing between the pinholes, f is the distance between the pinhole array and the LCD display plane and d is the distance of the virtual point from the eye. (Figure used with permission from Pamplona VF. Interactive Measurements and Tailored Displays for Optical Aberrations of the Human Eye. Doctoral thesis. Porto Alegre: The Federal University of Rio Grande do Sul, Brazil, 2012.).

Article Snippet: Scientists at the Massachusetts Institute of Technology and the company EyeNetra (USA) created the NETRA (Near Eye Tool for Refractive Assessment), a smartphone-based refractive tool that requires minimal training and which incorporates both objective and subjective refractive techniques for self-evaluation of refractive error.

Techniques: Software

Journal: BMJ Open Ophthalmology

Article Title: Comparison of the Near Eye Tool for Refractive Assessment (NETRA) and non-cycloplegic subjective refraction

doi: 10.1136/bmjophth-2021-000851

Figure Lengend Snippet: Stereo-pair scatter plots with comets for 34 participants joining non-cycloplegic subjective refraction (SR) and NETRA (Near Eye Tool for Refractive Assessment) measurements before cycloplegia (blue comets) and SR and NETRA measurements after cycloplegia (magenta comets) for 34 right (A and C) and left eyes (B and D). Each comet represents a single eye and consists of a dot and a line segment with dots representing either NETRA before or after cycloplegia and the ends of comets representing the corresponding non-cycloplegic SR. A single dot or point indicates that measurements were identical for the two methods for the eye concerned, whereas the longer the comet the greater the dissimilarity of measurements for the eye concerned. For all plots, the axis lengths in clinical terms are 7 D with 1 D tick intervals (or 7I D, 7J and 7K with tick intervals of 1I, 1J and 1K D). The origin is at O D (the 2×2 null matrix or emmetropia). Readers should allow their eyes to diverge to an imaginary point behind the page when observing each of the stereo-pairs in the figure. This results in a third plot appearing between the two halves of each stereo-pair and this central plot will have a three-dimensional appearance that is essential for properly evaluating aspects like position and direction of the comets, and hence illustrating the need for stereo-pairs.

Article Snippet: Scientists at the Massachusetts Institute of Technology and the company EyeNetra (USA) created the NETRA (Near Eye Tool for Refractive Assessment), a smartphone-based refractive tool that requires minimal training and which incorporates both objective and subjective refractive techniques for self-evaluation of refractive error.

Techniques:

Journal: BMJ Open Ophthalmology

Article Title: Comparison of the Near Eye Tool for Refractive Assessment (NETRA) and non-cycloplegic subjective refraction

doi: 10.1136/bmjophth-2021-000851

Figure Lengend Snippet: Bland-Altman plots of means versus differences for NETRA (Near Eye Tool for Refractive Assessment) before cycloplegia and non-cycloplegic subjective refraction (SR) for 34 right (first column) and left eyes (second column). (Each eye is indicated with a black dot or marker.) Parts (A) and (B) are the Bland-Altman plots for the stigmatic ( F I ) coefficients, part (C) and (D) the ortho-antistigmatic ( F J ) coefficients and part (E) and (F) the oblique-antistigmatic ( F k ) coefficients of power, respectively, for the right and left eyes. Note the differences in scales in the different parts.

Article Snippet: Scientists at the Massachusetts Institute of Technology and the company EyeNetra (USA) created the NETRA (Near Eye Tool for Refractive Assessment), a smartphone-based refractive tool that requires minimal training and which incorporates both objective and subjective refractive techniques for self-evaluation of refractive error.

Techniques: Marker