Effects of blue light–filtering intraocular lenses on the macula, contrast sensitivity, and color vision after a long-term follow-up

Abstract

After 5 years, there were no significant differences in color perception, scotopic contrast sensitivity, or photopic contrast sensitivity between the blue light-filtering (yellow-tinted) IOL and the IOL with a UV-light filter only (untinted). The potential advantage of the tinted IOL in providing protection to macular cells remains unclear.

Definition of population and randomization of sample in clinic surveys

“…The following step is to determine what population will be investigated. For example, when evaluating the efficacy of an intraocular lens (IOL) with yellow pigmentation in the prevention of macular degeneration related to age (ARMD), the population to be studied would be made up by patients operated by cataract, who received the implant of that IOL in one or more specific zones in a certain time (1)(2)(3) . In case the results may be considered different for patients under 50 years of age (less probability of developing AMD) and those over 70 years of age (more probability of developing ARMD), in order to increase the significance of data, one can restrict the population only for patients over 70 years of age.…”

Neutralization method for detecting the incidence of color perception changes after cataract surgery

“…The inclusion of UV light-filtering chromophores is one of these changes; however, blue light can still reach the retina without being filtered. 2 In recent years, the inclusion of yellow chromophores in the IOL material composition (blue light-filtering IOLs) has been suggested as a potential solution to prevent UV and blue light from reaching the retina. 3 However, despite the good visual outcomes achieved with this type of IOL, 4,5 there are some controversies about their use.…”

“…These include the potential side effects of blue light-filtering on contrast sensitivity, 4,6 color perception, 4,7-12 and even on circadian rhythm. 1 Several studies 2,4,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] have evaluated the effect of a yellow IOL on color discrimination after cataract surgery. Most did not find a change in color vision after the implantation of this type of IOL.…”

How to measure the precision of clinical study results

“…Sampling is when the analysis is performed based in a (representative) part of a population. In this stage, it is important to bear in mind that the only form of guarantee the representativity of that sample will be doing the selection randomly, so each element of the population will have exactly the same probability of being selected, without suffering influence on the part of the researcher (1)(2)(3).…”