title: Comparison of presbyopic additions determined by the fused cross-cylinder method using alternative target background colours.
abstract: OBJECTIVE
  To compare and contrast standard and alternative versions of refractor head (phoropter)-based charts used to determine reading addition.
  
  
  METHODS
  Forty one presbyopic subjects aged between 42 and 60 years were tested. Tentative additions were determined using a red-green background letter chart, and 4 cross-grid charts (with white, red, green, or red-green backgrounds) which were used with the fused cross cylinder (FCC) method. The final addition for a 40 cm working distance was determined for each subject by subjectively adjusting the tentative additions.
  
  
  RESULTS
  There were significant differences in the tentative additions obtained using the 5 methods (repeated measures ANOVA, p < 0.001). The mean differences between the tentative and final additions were <0.10 D and were not clinically meaningful, with the exception of the red-green letter test, and the red background in the FCC method. There were no significant differences between the tentative and final additions for the green background in the FCC method (p > 0.05). The intervals of the 95% limits of agreement were under ±0.50 D, and the narrowest interval (±0.26 D) was for the red-green background.
  
  
  CONCLUSIONS
  The 3 FCC methods with a white, green, or red-green background provided a tentative addition close to the final addition. Compared with the other methods, the FCC method with the red-green background had a narrow range of error. Further, since this method combines the functions of both the fused cross-cylinder test and the duochrome test, it can be a useful technique for determining presbyopic additions.
authors.affiliation: Department of Visual Optics, Kyungwoon University, Gumi, Kyungbuk, South Korea.
authors.forename: Sung-Hyun
authors.initials: SH
authors.lastname: Wee
authors.forename: Dong-Sik
authors.initials: DS
authors.lastname: Yu
authors.forename: Byeong-Yeon
authors.initials: BY
authors.lastname: Moon
authors.forename: Hyun Gug
authors.initials: HG
authors.lastname: Cho
mesh_terms: D000328:Adult; D003116:Color; D055253:Color Vision / Q000502:physiology; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011305:Presbyopia / Q000175:diagnosis*; D011932:Reading; D014787:Vision Tests / Q000295:instrumentation / Q000379:methods*