"differenceVA" function. Difference between uncorrected and corrected visual acuity

Computes the Efficacy by means of a bar graph of lines of difference between postoperative uncorrected and corrected visual acuity for cataracts or uncorrected preoperative visual acuity and corrected postoperative visual acuity in laser refractive surgery. 

This function calculates the standardized graph from a matrix of data of two columns:

  1. In Cataract Surgery: First column should contain the visual acuity without correction after surgery and the second column the visual acuity with correction after surgery.2  
  2. In Laser Refractive Surgery: First column should contain the visual acuity without correction after surgery and the second column the visual acuity with correction before surgery.1

In the case of procedures with multifocal intraocular lenses, the function allows to modify the labels depending on whether the data entered correspond to results of far visual acuity, intermediate or near. The function also computes the Efficacy Index as the ration between the UDVA/CDVA.3

Examples:

Cataract surgery:

  • [EI] = differenceVA(VA,1,'en','far'); Computes the figure for 1 month after cataract surgery for visual acuity at far distance.
  • [EI] = differenceVA(VA,1,'en','intermediate'); Computes the figure for 1 month after cataract surgery for visual acuity at intermediate distance.
  • [EI] = differenceVA(VA,1,'en','near'); Computes the figure for 1 month after cataract surgery for visual acuity at near distance.

Laser refractive surgery:

  • [EI] = differenceVA(VA,1,'en','far'); Computes the figure for 1 month after surgery for visual acuity at far distance.

Below you have the help of the function. For more information about "refractiveAnalysis" Toolbox please Contact the author

%   Computes the Efficacy by means of a bar graph of lines of difference
%   between postoperative uncorrected and corrected visual acuity for
%   cataracts or uncorrected preoperative visual acuity and corrected
%   postoperative visual acuity in laser refractive surgery.
%
%   DESCRIPTION
%
%   Computes de Figure B from the standard of the JRS
%
%   PARAMETERS
%
%   VA   Two columns matrix
%        In Catarat Surgery with IOLs [PostUDVA PostCDVA](1)
%        In Laser Refractive Surgery  [PreUDVA PostCDVA](2)
%
%   month       Number of months after surgery
%      
%   language    Language for the labels 'es' for Spanish or 'en' for English
%
%   distance    'far','intermediate','near' (For LRS introduce far)
%
%   RETURNS
%
%   EI        Efficacy index as the ratio of UDVA/CDVA(3)
%
%   EXAMPLE
%
%   [EI] = differenceVA(VA,1,'es','far')
%
%   VERSION
%   
%   1.0.1
%
%   demo data "efficacy.mat"
%
%   REFERENCES
%
%   1.- Reinstein DZ, Archer TJ, Srinivasan S, et al. Standard for Reporting Refractive Outcomes of Intraocular Lens–Based Refractive Surgery. J Refract Surg. 2017; 33: 218–22. 
%   2.- Reinstein DZ, Archer TJ, Randleman JB. JRS Standard for Reporting Astigmatism Outcomes of Refractive Surgery. J Refract Surg. 2014; 30: 654–9. 
%   3.- Koch DD, Kohnen T, Obstbaum SA, Rosen ES. Format for reporting refractive surgical data. J Cataract Refract Surg. 1998; 24: 285–7.