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Tablet app aston halometer for the assessment of dysphotopsia

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Session Details

Session Title: Combined Cataract Surgery Techniques. Surgical Devices

Session Date/Time: Saturday 05/09/2015 | 08:30-10:30

Paper Time: 09:41

Venue: Main Auditorium

First Author: : J.Wolffsohn UK

Co Author(s): :    P. Buckhurst   S. Naroo   L. Davies   S. Shah   A. Kingsnorth   T. Drew     

Abstract Details


To assess the validity and repeatability of a new tablet based halometer, designed to allow the objective quantification of an aspect of dysphotopsia commonly encountered with multifocal intraocular lenses.


Setting was Aston University Eye Care Clinic, Birmingham, UK (University Clinic)


The Aston Halometer comprises of a bright Light-Emitting-Diode (LED) glare source in the centre of an iPad4 placed at 2m. Letters, subtending 0.21°, were moved centrifugally from the LED in 0.05º steps in 8 orientation separated by 45° for each of 4 contrast levels (1000,500,100&25 Weber contrast units [Cw]) in random order. Bangerter foils were inserted to simulate monocular glare conditions in 20 subjects (aged 27.7±3.1 years). The Oculus C-Quant was also used with each of the foils to measure the level of straylight over the retina. Halometry and straylight repeatability was assessed at a second visit.


Halo size increased with the different Bangerter foils and target contrasts (F=29.564, p<0.001) as expected and in a similar pattern to straylight measures (F=80.655, p<0.001). Lower contrast letters showed better sensitivity, but larger glare-obscured areas resulting in ceiling effects due to the screen's field-of-view, with 500Cw being the best compromise. Intra-observer and inter-observer repeatability of the Aston Halometer was good (500Cw: 0.84-0.93 and 0.53-0.73) and similar to the CQuant.


The Aston Halometer provides a sensitive, repeatable way of quantifying a patient recognised form of disability glare in multiple orientations to add objectivity to subjectively reported discomfort glare.

Financial Interest:

One of the authors gains financially from product or procedure presented

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