Refractive Status and Accommodation Response Under Different Experimental Conditions.

VA will be measured with an Early Treatment Diabetic Retinopathy Study (ETDRS) chart

Objective refraction will be measured using an auto-kerato-refractometer/aberrometer

Objective monocular accommodation amplitude measurements are obtained dynamically by measuring the subject's dioptric change while the participant focuses on a virtual object that moves from distance

"The subjective monocular accommodation amplitude measurements are carried out by the push-up method and proceeds as follows:~* The ECP presents a near vision test card corresponding to a 0.8 (8/10) acuity line, or the smallest readable line if acuity is poor, or the smallest readable text.~* Instructions to the subject: Look at the smallest line of letters and try to see them clearly for as long as possible when I bring them closer; tell me when they start to blur and stay blurred.~* The ECP slowly brings the test card closer~* The ECP note the distance of the test card from the glasses as soon as the vision is blurred. Continue to move the test closer to check that vision remains blurred.~The amount of accommodation in this eye is equal to the proximity (= 1/distance) of the test when the blur is just perceived."

"The subjective monocular accommodation facility measurements are carried out by the Rock method and proceeds as follows:~* The ECP presents at 40cm a near vision test card corresponding to 80% of the VA.~* The ECP gives to the participant a flipper +/- 2 Dioptre~* Instructions to the subject: Look at the test and add the -2.00 D (Sphere) flipper, as soon as it's clear, return the flipper to present a +2.00 D (Sphere), as soon as it's clear, return the flipper etc… You have to do the maximum number of rotations in one minute."

This questionnaire relating to the use of the near vision will be submitted

After each near vision measurement, the participant should rate, on a Visual Analogic Score (0-10), the difficulty encountered, from 0: extremely easy to 10: extremely difficult. The participant may also specify the reasons for the difficulty(ies) encountered during the measurement.

A subjective evaluation questionnaire will be submitted to the participants at the end of the visit.