In short
Abbott Medical suggests that colour used in intraocular lenses may have an impact on a patient’s melatonin level and consequently affect circadian rhythms. Far fetched as that sounds it seems there is some evidence to support it.
Background
According to a recent article in The New York Times, cited by Abbott, clinical studies suggest that the gradual yellowing of the eye’s lens and the narrowing of the pupil that occur with age filter out blue light and can affect older patients’ circadian rhythm and health.
Circadian rhythm is affected by melatonin, and blue light entering the eye is known to help regulate melatonin levels.
The NYT article apparently goes on to discuss cataract patients and the fact that about one-third of intraocular lenses (IOL) implanted worldwide during cataract procedures are blue light-blocking lenses, intended to reduce the theoretical risk of macular degeneration by limiting exposure to potentially damaging UV rays.
Abbott’s offering
Abbott Medical Optics’ Tecnis IOL is clear and was developed to provide UV-blocking protection while allowing the transmission of healthy blue light needed for optimal night-time vision and healthy circadian rhythm.
Scientists in Sweden studied patients who had cataract surgery to remove their clouded lenses and implant clear intraocular lenses. They found that the incidence of insomnia and daytime sleepiness was significantly reduced. Another study found that patients had improved reaction time after their cataract surgery.
Clinician comments
Quoted in the aforementioned Swedish article is Dr. Patricia Turner, an ophthalmologist who has written extensively about the effects of the aging eye on health.
“We believe that it will eventually be shown that cataract surgery [with clear lenses] results in higher levels of melatonin,” Turner said, helping to keep patients’ circadian rhythms on track.
We say
We’d like to review the Swedish study because the argument seems to entirely hinge on its findings. Again though it does feel like a stretch to imagine that IOL colour has such an impact, but we’ll reserve judgement.
Source: Abbott Medical
