title: Macular pigment optical density before and after cataract extraction.
abstract: OBJECTIVE
  Psychophysical methods of measuring macular pigment (MP) use comparisons of short- and midwave light in the fovea and parafovea to derive optical density estimates. This light must pass through the crystalline lens before absorption by the MPs can occur. The effect of lens absorption on these measures has not been adequately determined. The present study assesses the influence of lens absorption on MP measurements by comparing MP optical density (MPOD) measured before and after cataract extraction.
  
  
  METHODS
  MPOD was measured using flicker photometry in free view at 458 nm with a 1 degrees stimulus. Twenty-nine eyes from 24 patients with cataracts sufficiently severe to require cataract extraction were evaluated.
  
  
  RESULTS
  In the entire group of 24 patients, the mean (+/-SD) age measured 68.7 +/- 9.5 years, and the mean MPOD measured 0.19 +/- 0.11. For all 29 eyes measured, MPOD averaged 0.206 +/- 0.13 before and 0.18 +/- 0.12 after cataract extraction. MPOD measurements at the two time points (mean 8.1 +/- 4.7 weeks after surgery) were highly correlated (r = +0.58), suggesting that a cataractous lens does not influence the MP measurement technique.
  
  
  CONCLUSIONS
  Psychophysical techniques can be used to obtain reliable measurements of MP in elderly subjects, even in those with cataracts. Moreover, differences in retinal illuminance due to varying opaqueness of the crystalline lens do not seem to have a measurable influence on MPOD.
authors.affiliation: Retina Service, Department of Ophthalmology, Indiana University School of Medicine, 702 Rotary Circle, Indianapolis, IN 46260, USA. tciulla@iupui.edu
authors.forename: T A
authors.initials: TA
authors.lastname: Ciulla
authors.forename: B R
authors.initials: BR
authors.lastname: Hammond
authors.forename: C W
authors.initials: CW
authors.lastname: Yung
authors.forename: L M
authors.initials: LM
authors.lastname: Pratt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000150:complications*; D006801:Humans; D019654:Lens Implantation, Intraocular; D008266:Macula Lutea / Q000737:chemistry*; D008875:Middle Aged; D018918:Phacoemulsification; D010783:Photometry; D012168:Retinal Pigments / Q000032:analysis*
chemical_list: D012168:Retinal Pigments