Halometer app may quantify patient-reported halos

Issue: March 10, 2016

A halometer application operated on an iPad reliably and objectively quantified the size of patient-reported halos, according to a study.

The prospective study included 20 subjects who had a mean age of 27.7 years.

The Aston halometer measured the degree of obscuration of a target from an LED glare source on an iPad 4. Letters were moved centrifugally from the LED in 0.05° increments in eight directions of orientation separated by 45° for four contrast levels.

Bangerter occlusion foils in front of the right eye and occlusion of the left eye simulated monocular glare. Subjects were placed 2 m from the iPad screen in a dark room, and a researcher controlled the iPad from an iPhone via Bluetooth.

Halo size increased significantly and predictably with differing occlusion foils and target contrasts in a pattern similar to straylight measures (P < .001).

Compared with no filter, straylight increased with the 0.8 occlusion foil (P < .001). The 0.6 occlusion foil also increased the straylight (P < .001).

“Lower contrast letters showed larger glare-obstructed areas, resulting in ceiling effects caused by the screen’s field of view,” the study authors said.

Intraobserver and interobserver repeatability with the halometer was good and comparable to readings with the straylight meter. – by Matt Hasson

Disclosure: Drew and Wolffsohn report a financial interest in Aston Eye-Tech Ltd. The other authors report no relevant financial disclosures.

Published by:

Sources/Disclosures

Collapse

Source:

Buckhurst PJ, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2015.05.041.