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The electronic Consent Form in Clinical Research Apps

The technology advances have led the emergence of new ways for collecting data in clinical research. An example of this is the ResearchKit Framework from Apple which facilitates the process in the design of new applications used in clinical research, including the consent form.

"accuracy" function. For spherical equivalent and astigmatism

The most important outcome of refractive surgery is the refraction, therefore with the Accuracy plot you can create a scattergram of the attempted refractive change vs. the achieved refractive change for each eye if you are analyzing the Spherical Equivalent (Figure C from the nine standard graphs) or The Target Induced Astigmatism versus the Surgically Induced Astigmatism if you are analyzing astigmatism data (Figure G from the nine standard graphs). 

"stability" function. The change on the spherical equivalent with time

In laser refractive surgery procedures it is important to control the stability of the postoperative refraction with time. For this purpose, the standard proposes a stability graph that shows the variation of the postoperative spherical equivalent at different follow-up visits through the mean and standard deviation of the sample. 

"safetyVA" function. Difference between postoperative and preoperative corrected distance visual acuity

This is the most commonly used measure of safety because it answers the question, “If the refractive outcome is not totally acceptable, can the patient put glasses on again and see as well as they did before surgery?” A change of 1 Snellen line is within the range of normal biological variability for repeated measures, and therefore is not a meaningful change. A change of 2 or more Snellen lines has been generally adopted as the standard for safety.(1)

"muPentacam" Function. Correcting Pentacam chord-mu for conventional notation

This function corrects the Kappa or chord-mu obtained from Pentacam in order to move the center of coordinates to the pupil center instead of the vertex normal. Furthermore, it corrects the differences of sign from right and left eyes in order to combine both eyes in the same plot.