BETTER MEASURES NEEDED FOR GLARE AND HALOS

The importance of testing disability glare in patients is increasing as surgical technology and patient expectations advance, Oliver Stachs MD, Germany, told a packed audience attending the Clinical Research Symposium on Dysphotopsia at the XXXIII Congress of the ESCRS in Barcelona.

“Clinicians and researchers need to understand the principles behind halo/glare measurement in order to be able to use available measures,” he said.

Dr Stachs noted that simply defining glare and halos is fraught with difficulty, as the terms have many different meanings to different people.

“When a patient states that they have problems with glare or halo there are many distinct visual effects that they may be describing. My personal opinion as a physicist is that it is difficult to give exact definitions for halo and glare due to the overlap between neural and intraocular light scattering effects,” he said.

Approaches to quantify glare include subjective methods such as score charts or patient questionnaires, or objective methods using any one of a number of devices available such as the halometer, glaremeter, stray light meter, brightness acuity tester, Berkeley glare test and straylight meter.

“There are many extremely interesting approaches and devices available, but the comparability between them is not given and they all have inherent advantages and disadvantages,” he said.

Going forward, Dr Stachs said that there was a clear need for some universally agreed method to quantify halos and glare.

“Successful glare tests that are cheap, accessible, valid and reliable are required and further research is necessary if a more universally applicable test is to be found,” he added.