Minimum amount of spherical aberration detected by patients

Session Details

Session Title: Imaging I

Session Date/Time: Monday 12/09/2016 | 14:30-16:30

Paper Time: 15:42

Venue: Hall C2

First Author: : P.Artal SPAIN

Co Author(s): :    S. Manzanera                    

Abstract Details

Purpose:

Both in modern corneal refractive and cataract surgery, good quality of vision in patients require a precise control of the induced spherical aberration (SA). However, while the minimum values of residual refractive errors that may affect vision are well-known, it is not yet well determined the minimum amount of SA that patients can detect visually. In this context, the purpose of this study was to determine the SA thresholds that produce changes in perceived images.

Setting:

Laboratorio de Optica, Universidad de Murcia, Spain

Methods:

We used an Adaptive Optics Visual simulator to perform visual testing with control of the optical aberrations induced in the patient’s eye. Measuring the SA threshold was based on a flickering detection procedure. Subjects were presented a tumbling E letter while the eye’s optical conditions alternated. In one presentation the subject has his natural SA corrected and in the other a certain amount of SA was induced. Subject were allowed to change the value of induced SA searching for the threshold for the perception of flickering that was considered as the threshold for the detection of SA.

Results:

Measurements were performed in 3 normal subjects for 4 mm artificial pupil diameter at best focus and with residual astigmatism corrected. Threshold estimations for the detection of SA were performed for both positive and negative values. In average, for positive SA the minimum amount of SA required to be detected in the perceived images was of 0.05 microns and for negative SA -0.03 microns (referred to 4-mm pupil). Inter-subject variability represented by the standard deviation were 0.02 and 0.01 microns for positive and negative respectively.

Conclusions:

We used an adaptive optics instrument to determined the minimum amount of SA required to be visually noticeable. This value (around 0.04 microns for 4-mm pupil) may have important practical implications in corneal and cataract surgery to set the minimum required precision when SA is induced or controlled during the surgeries.

Financial Disclosure:

NONE