Blocking the transmission of ultraviolet light (UV) through a contact lens may have an effect in maintaining the eye's macular pigment density, according to new research presented today at the 2012 British Contact Lens Association Clinical Conference. Existing research suggests that a higher level of macular pigment appears to have a protective effect against age-related macular degeneration, a major cause of severe vision loss for people over the age of 55.
Forty pre-presbyopic patients (mean age = 30) who had worn contact lenses for around five years, participated in this novel introductory study which retrospectively examined the effects of wearing UV-blocking contact lenses on macular pigment density and accommodation (ability of the eyes to maintain a clear focus on an object as its distance varies).
Twenty subjects wore UV-blocking contact lenses while the other 20 subjects wore a contact lens material with minimal UV-blocking properties. Researchers evaluated participants' ocular health, macular pigment density levels and measured their accommodative response
All subjects were matched for age, gender, race, body-mass-index, diet, lifestyle, UV exposure, refractive error and visual acuity. Macular pigment density levels were significantly greater (p<0.05) in eyes that had worn UV-blocking contact lenses (0.41+/-0.13) compared to eyes that had worn non UV-blocking contact lenses (0.33+/-0.15).
Ocular health (p>0.05), amplitude-of-accommodation (p=0.217), range of clear focus (p=0.783) and objective stimulus response curve (p=0.185) were not statistically different in eyes that had worn UV-blocking contact lenses compared to the others. Although not statistically significant, UV blocking contact lens wearers consistently showed a higher accommodative response than those wearing contacts with minimal UV-blocking.