Objective evaluation of refractive data and astigmatism: quantification and analysis

Abstract

The aim of this study was to present methods to improve the analysis of refractive data.

Propranolol and Periocular Capillary Hemangiomas: Assessment of Refractive Effect

“…22 If they are treated independently as vectors, this leads to or (+2/+2 90 ) + (+1/+1 180 ) = +4/+1 90 , which is the correct result. 22 It is evident that the space of cylinders is not closed under addition or subtraction (ie, a cylinder plus a cylinder does not necessarily equal a cylinder). Clearly, in any analysis of changes in refractive powers, the components need to be treated as co-variates.…”

“…Mean astigmatism was calculated by subtracting the spherical equivalent from the refractive power. 12,22 the true effect, the cylinder subtraction method may overestimate the level of statistical significance when applied to the changes in astigmatism. In addition, it is intuitively obvious and demonstrated well by subjective clinical refraction that cylindrical and spherical lens components are not independent variables.…”

“…Consider a refractive power of S/C A . It follows that 12,22 Thus, for example, if one applies this to a cylinder, we have…”

Corneal Apical Scar After Hyperopic Excimer Laser Refractive Surgery: Long-term Follow-up of Treatment With Sequential Customized Therapeutic Keratectomy

“…To assess the long-term safety and efficacy of SCTK, the preoperative values were compared with the last follow-up available for all patients. Refractive outcome differences were assessed by dioptric power matrix evaluation using the approach suggested by Kaye et al 11,12 Data are expressed, in this case, as mean refraction and 95% confidence intervals.…”

Sequential Customized Therapeutic Keratectomy for Reis-Bücklers' Corneal Dystrophy: Long-term Follow-up

“…Refractive outcome differences were assessed by dioptric power matrix evaluation using the approach suggested by Kaye. 18 Data are expressed as mean ± standard deviation refraction (sphere, cylinder, and axis).…”