The combatant is likely to carry out missions any time, any place, day or night. The very strong degradation of natural vision performance in these conditions justifies the use of visual replacement means, based on optronic sensors whose sensitivity is more adapted to these luminous environments than that of the human eye.

The duration and repetition of missions carried out with night vision sensors lead to visual complaints from users.

The literature on night vision binoculars adjustment states that a binocular adjustment of the equipment provides more convex settings. The latter would then limit the strain on the accommodative component, which is one of the possible sources of operator visual fatigue. In order to allow a more appropriate adjustment, it is proposed to rely on a measurement of the refraction (optical defect of the eye) of each operator. Like binocular adjustments, binocular refractive methods would limit accommodative stimulation and thus visual fatigue. However, these methods are little used in favour of conventional methods. It is therefore necessary to evaluate the interest of binocular refraction for the adjustment of night vision binoculars.

The purpose of this study is to compare refraction measurements by procedure in adult subjects free of ophthalmological disorders.

Inclusion Criteria:

• Age over 18 ;
• Non-presbyopic subject;
• Stereoscopic acuity ≤ 60 arc seconds.

Exclusion Criteria:

• Accommodative insufficiency;
• Accommodative inertia;
• Compensation by orthokeratology (i.e. night lenses);
• Present or past binocular pathology (strabismus or amblyopia);
• Pregnant or nursing woman;
• Incomprehension of French (written and spoken).

Healthy adults