Clinical Trial: Do Blue-Blocking Lenses Block Blue Colour From Our Lives?

Study Status: Completed
Recruit Status: Unknown status
Study Type: Interventional

Official Title: Do Blue-Blocking Lenses Block Colour From Our Lives? A Randomised Controlled Study Measuring Colour Vision Using the Gold Standard Colour Vision Test (an Anomaloscope)in Patients With Blue Light Filte

Brief Summary: To measure colour vision in patients with a blue light filtering lens implant in one eye and non-tinted implant in the other eye (and compared this group with a control group with bilateral non-tinted implants) and to determine whether blue light filtering lenses limit colour vision

Detailed Summary:

As we all age, the natural lens inside our eyes becomes denser, hazy and more yellow in colour. In other words, cataracts develop. In order to enable clear vision again, cataract surgery is performed. This involves removing the natural lens from the eye and replacing it with a synthetic lens implant inside the eye. Cataract surgery with insertion of a lens implant was first done in 1948 but didn't become routine until the early 1980s. Around this time, awareness about the harmful effects of UV light were raised and by 1986, lens implants routinely had a UV filter incorporated into them.1 As early as 1992, a study examining patients who had had a high occupational exposure to blue and visible light, concluded that there is a positive association between long term exposure to visible light and age related wear and tear change at the back of the eye, termed age related macular degeneration (AMD).2 This theory was supported by several studies which have reported an increased rate of progression of AMD in patients after cataract surgery with a clear lens implant (It is known that clear lens implants transmit more blue light to the back of the eye compared with the natural aging lens).3 Laboratory studies in 2000 showed that blue light causes damage to aging retinal cells (the nerve cells at the back of the eye which are important in enabling us to see), more so than green light or white light.4 Experimental studies with rats also showed that exposure to blue light was 30 times more damaging to retinal cells compared with yellow light.5 A further laboratory study in 2004 confirmed that by protecting aging retinal cells with a blue light filtering lens, damage caused by blue light is prevented.6 Yellow tinted, blue light filtering lens implants have been in production since 1991, first by Hoya in Tokyo and now by Alcon as well. Alcon produce the Acrysof Natural lens implant which has been designed to mimic the 53 year old natur
Sponsor: London North West Healthcare NHS Trust

Current Primary Outcome:

  • To objectively determine whether colour vision is reduced with a blue-light filtering
  • intraocular lens compared with a colourless intraocular implant in cataract surgery


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • To determine whether patients subjectively are able to tell whether they have been
  • implanted with yellow tinted intraocular lens during their cataract surgery or colourless one


Original Secondary Outcome: Same as current

Information By: London North West Healthcare NHS Trust

Dates:
Date Received: November 22, 2006
Date Started: October 2006
Date Completion:
Last Updated: May 11, 2007
Last Verified: May 2007