Spectacle Tints and Thin-Films for Migraine

Approximately 6% of men and 18% of women are afflicted with migraines. (Stovner et al., 2006)
Over 90% of patients with migraines report a sensitivity to light (photophobia) during
headaches. (Evans et al., 2008) Some migraine sufferers report that light can trigger a
migraine and some have a chronic sensitivity to light (Main et al., 1997). Migraineurs are
especially sensitive to non-incandescent lighting sources such as fluorescent lights,
computer monitors, and gas-vapor lamps (Katz and Digre, 2016).

The pathway that mediates photophobia appears to involve intrinsically photosensitive retinal
ganglion cells ("IPRGCs"; Hattar et al., 2002) and trigeminal afferents (Noseda et al., 2010;
Digre and Brennan, 2012). These retinal cells do not require input from photoreceptors to be
activated by light, and they have been shown to be responsible for circadian rhythm
entrainment and the pupillary light reflex. As such, these cells constitute a pathway
separate from that of the visual pathway (Güler et al., 2008). IPRGCs contain the chromophore
melanopsin. In these cells, 480 nm light (in the blue-green portion of the visible spectrum)
isomerizes melanopsin and triggers the phototransduction cascade. However, IPRGCs can also be
stimulated by rods and cones. Thus, IPRGCs can be stimulated directly by 480-nm light or
indirectly by any light in the visible spectrum.

In the present study, the investigators will use a neutral gray tint to decrease stimulation
of the eye by all wavelengths in the visible spectrum. The investigators will compare this
intervention to a thin-film spectacle coating designed to specifically block 480-nm light.
The gray tint will decrease both direct and indirect stimulation of the IPRGCs by blocking
all wavelengths of the visible spectrum. The 480-nm thin-film will specifically target direct
stimulation of the IPRGC.

All tints and thin films will be calibrated such that the optical density, that is the
overall "darkness" of all study lenses, will be the same. All study lenses will appear to
have the same overall light blocking effect to study subjects. The lenses are intended to be
a preventative or prophylactic treatment for chronic migraine.

Inclusion Criteria:

- Subjects must meet the International Headache Society criteria for chronic migraine
(International Classification of Headache Disorders, 3rd edition (Headache
Classification Committee of the International Headache Society, 2013). All subjects
must be between the ages of 18 and 60 years-old.

To be included in the study, in the best judgment of the investigator, subjects must be
stable on their current migraine treatment regimen. Stability is defined as no major
changes in therapy contemplated within the next 4 months.

Exclusion Criteria:

- Subjects with other light sensitive conditions, such as iritis and blepharospasm, will
be excluded. Subjects with best-corrected visual acuity less than 20/40 will be
excluded. Subjects with diseases of the retina, such as diabetic retinopathy and
macular degeneration will be excluded. Subjects using medications known to affect the
eye will be excluded (e.g. chloroquine, hydroxychloroquine, ethambutol, amiodarone).
Due to constraints on the manufacture and mounting of study lenses into study frames,
the study must exclude subjects who are very nearsighted (more than 4 diopters),
subjects who are very farsighted (more than 2 diopters), and subjects who have more
than 2.5 diopters of astigmatism.

Because of the cyclical effects of botulinum toxin injections and other nerve blocks,
patients undergoing these treatments will be excluded. Subjects must not have had any
injections or blocks within 4 months of enrollment and should not receive any further
blocks until they exit the study.

Subjects with continuous daily headache (a headache frequency of 100%) will be excluded.
Subjects who do not have a headache frequency of at least 50% will be excluded.

Subjects with medication overuse headache will be excluded. A patient with a history of
medication overuse who has not overused abortive medications for the past 4 months can be
included.

Subjects who abuse alcohol or use illicit drugs will be excluded. Subjects considered to be
from vulnerable populations will be excluded, including pregnant women, prisoners, subject
who are mentally disabled, subjects with cognitive or decisional impairment, and wards of
the state