Tablet app aston halometer for the assessment of dysphotopsia

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

Purpose:

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:

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

Methods:

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.

Results:

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.

Conclusions:

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