infacility of accommodation

Infacility of accommodation, usually called accommodative infacility, is difficulty changing the level of the accommodative response. The latency and speed of accommodation are abnormal while the amplitude is normal, so the patient cannot use that amplitude quickly or for long periods.¹ The condition is also called accommodative inertia, and it can show as a considerable lag between the stimulus to accommodation and the response.²

The most characteristic symptom is difficulty changing focus from one distance to another, and patients often report blurred distance vision right after sustained near work.^1,2 Testing shows poor monocular and binocular accommodative facility with both plus and minus lenses, along with reduced negative and positive relative accommodation.¹

The diagnosis requires a deficiency in both stimulating and relaxing accommodation. A patient who fails facility testing only with -2.00 lenses has accommodative insufficiency, and one who fails only with +2.00 lenses has accommodative excess.¹