The effect of bright light exposure on pupillary fluctuations in healthy subjects

Light therapy: is it safe for the eyes?

OBJECTIVE

Light therapy has become an increasingly popular treatment for depression and a range of other neuropsychiatric conditions. Yet, concerns have been raised about the ocular safety of light therapy.

METHOD

We conducted the first systematic review into the ocular safety of light therapy. A PubMed search on January 4, 2017, identified 6708 articles, of which 161 were full-text reviewed. In total, 43 articles reporting on ocular complaints and ocular examinations were included in the analyses.

RESULTS

Ocular complaints, including ocular discomfort and vision problems, were reported in about 0% to 45% of the participants of studies involving light therapy. Based on individual studies, no evident relationship between the occurrence of complaints and light therapy dose was found. There was no evidence for ocular damage due to light therapy, with the exception of one case report that documented the development of a maculopathy in a person treated with the photosensitizing antidepressant clomipramine.

CONCLUSION

Results suggest that light therapy is safe for the eyes in physically healthy, unmedicated persons. The ocular safety of light therapy in persons with preexisting ocular abnormalities or increased photosensitivity warrants further study. However, theoretical considerations do not substantiate stringent ocular safety-related contraindications for light therapy.

On the application of light therapy in German-speaking countries

Many studies have investigated seasonal affective disorder (SAD; fall-winter-depression) and its treatment with light therapy (LT). However, to the best of our knowledge, no other study has investigated the usage of LT in Europe since 1994. Thus, we performed a survey in hospitals with adult psychiatric departments in German-speaking countries by questionnaire. First, a questionnaire was constructed, considering also recent developments in LT. This questionnaire was sent to all hospitals with adult psychiatric departments listed in the "Deutsches Krankenhaus Adressbuch," which contains hospitals from all German-speaking countries (Germany, Switzerland, and Austria). Non-responders were asked to answer the questionnaire by mail and by phone. We achieved a completion rate of 58%. Data show almost no relevant, non-artificial differences between countries as well as between type of hospital. LT is more frequently used in university and state hospitals than in other types of treatment facilities. Compared to 1994, the major findings are (1) a substantial increase in the use of LT from 13.0 to 69.8% with no differences between Germany, Austria, and Switzerland, (2) this increase is mostly due to treatment for various forms of depression and further possible applications are less often considered, (3) there is a shift in the usage of LT from monotherapy to combination of pharmacotherapy with LT as an adjunctive treatment, and (4) a north-south comparison showed no substantial differences. Considerably higher rates of usage of LT have been found compared to the last survey in German-speaking countries taking place in 1994. Usage almost tripled; however, possible indications for LT other than SAD and non-seasonal depression are not applied to full extent. Further efforts on the propagation of LT should therefore be undertaken, with the same rigorous studies as for pharmacotherapy.