Subjective blur limits for cylinder

Optom Vis Sci. 2010 Aug;87(8):E549-59. doi: 10.1097/OPX.0b013e3181e61b8f.


Purpose: The purpose was to compare subjective blur limits for cylinder and defocus.

Methods: Blur was induced with a deformable, adaptive-optics mirror when either the subjects' own astigmatisms were corrected or when both astigmatisms and higher-order aberrations were corrected. Subjects were cyclopleged and had 5-mm artificial pupils. Black letter targets (0.1, 0.35, and 0.6 logMAR) were presented on white backgrounds.

Results: For 10 subjects, blur limits were approximately 50% greater for cylinder than for defocus (in diopters). Although there were considerable effects of axis for individuals, overall, this was not strong, with the 0 degrees (or 180 degrees ) axis having approximately 20% greater limits than oblique axes. In a second experiment with text (equivalent in angle to N10 print at 40 cm distance), cylinder blur limits for six subjects were approximately 30% greater than those for defocus; this percentage was slightly smaller than for the three letters. Blur limits of the text were intermediate between those of 0.35- and 0.6-logMAR letters. Extensive blur limit measurements for one subject with single letters did not show expected interactions between target detail orientation and cylinder axis.

Conclusions: Subjective blur limits for cylinder are 30 to 50% greater than those for defocus, with the overall influence of cylinder axis being 20%.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Artificial Organs
  • Astigmatism / therapy*
  • Corneal Wavefront Aberration / therapy*
  • Eyeglasses*
  • Humans
  • Middle Aged
  • Mydriatics / administration & dosage
  • Pupil
  • Refraction, Ocular / physiology*
  • Refractive Errors / diagnosis*
  • Refractive Errors / etiology
  • Refractive Errors / physiopathology
  • Visual Acuity / physiology*
  • Young Adult


  • Mydriatics