Kate describes near heterophoria to her patients as where their eyes aim in space – the posture of their vergence system – and esophoria is our key enemy in the myopia control battle.

Assessing horizontal fusional reserves at near gives you the measure of your patient’s stamina, or ‘petrol in the tank’ to be able to manage their phoria, or ‘posture’.

Given that a normal lag result is +0.50, I would generally prescribe an add which is the accommodative lag result subtracting 0.50, so the resulting final lag is within the normal range. For example, a lag of +2.00 results in a +1.50 Add; a lag of +1.50 results in a +1.00 Add. However, this formula may not work if:

Assessing accommodative function at near is a vital component of understanding the myopia profile of your patient. Myopic progression in children and adults can be influenced by binocular vision function.