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Cross polarized spectacles in photosensitive epilepsy
S Jain1, G Woodruff, E A Bissessar
1Department of Ophthalmology, Leicester Royal Infirmary and Northampton General Hospital, United Kingdom.
Purpose:
To investigate the role of cross polarized spectacles in the treatment of photosensitivity demonstrable by EEG.
Method:
Patients receiving an EEG who tested positive for photosensitivity were invited to participate in the study. The most sensitive light flicker frequency causing a photic response was determined for each patient. Stimulation was repeated with 2 different pairs of spectacles--1 conventionally polarized and the other cross polarized. An EEG was obtained in each case and reported by a neurophysiologist who was unaware of the identity of the 2 types of spectacles.
Results:
We tested 19 patients, 8 to 18 years of age. Two patients did not benefit from either pair of glasses. In 17 patients, the photic response was greatly diminished or eliminated by polarizing spectacles. In 1 patient, conventional polarized glasses helped, but the cross polarized spectacles did not. In 6 patients, both types of spectacles were equally effective; in 10 patients, cross polarized spectacles were more effective than conventionally polarized spectacles.
Conclusion:
The role of cross polarized spectacles in the management of photosensitivity in a clinical situation merits further investigation.