Abstract
Purpose:
We report here our clinical finding that wearing artificial pupil contact lenses (APCLs) substantially reduces the severe light sensitivity (LS) of photophobia (PP) and light-induced headache (LHA), possibly related to head trauma, as reported by young veterans referred to our VA Visual Rehabilitation Clinic. These otherwise ocular normal patients are very light sensitive, even to normal room lighting conditions, and typically wear dark (1 log neutral density), wrap-around sunglasses during their waking hours both indoors and outdoors. APCLs have been previously used to control light sensitivity from anterior segment defects, typically holes in the iris.
Methods:
We have used a 4.5 mm APCL that produces a visual field cut beyond 70 degrees eccentricity and reduces light entering the eye by at most 30%, compared to the 90% reduction of the dark sunglasses. Patients received a complete ocular health workup, including optical correction, near triad examination, dilated retina and anterior segment exams, and visual field testing. A multi-part questionnaire with 0-10 rating scales for subjective assessments of LS & LHA discomfort and interference with daily living activities is administered. Patients are followed and after one month return for re-examination including the questionnaires.
Results:
We have examined the response in 18 patients who have been fitted with binocular APCLs. Every patient reported substantial benefits with chronic use of APCLs. LS scores dropped 50% (Signed Rank p<.001) with major reductions in LHA. Patients are able to avoid wearing sunglasses in all but direct sunlight conditions, have re-engaged in normal activities, and indicate increased positive interactions with family members and co-workers resulting from not ‘hiding’ behind sunglasses. Removing the APCLs returns the patient to apparent pre-treatment sensitivity levels.
Conclusions:
These observations suggest that peripheral light exerts an unexpectedly strong control over PP symptoms. Restoring the central visual field to normal light levels by wearing APCLs, breaks the chronic dark adaptation problems associated with wearing dark sunglasses. The dynamic interaction between the pupil and the APCL that controls actual light levels needs further study. The use of APCLs to treat PP improves upon currently available treatment and suggests avenues for research into the origins of PP and its sequelae.
Keywords: 466 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials •
611 neuro-ophthalmology: cortical function/rehabilitation •
667 pupil