Visual acuity is usually not measured when the pupils are dilated, and the results of dilated optometry are usually more accurate in clinical practice. For children, the accuracy of the results is very high. The purpose of dilating the pupils is to relax the eye adjustment without masking the true degree of vision, so as to measure a more accurate optometry result. Children are in their growth period and their ciliary muscles are highly regulated, so if they are tested directly without dilating their pupils, their true prescription will likely be masked. For adults in their 40’s, the difference between the results of dilated and direct optometry is minimal because the ciliary muscle’s ability to regulate decreases with age. The primary purpose of dilating the pupils in adults is to enable the doctor to observe the remaining eye tissues for other pathologies, not for optometry. It is recommended that patients with abnormal optometry results seek medical attention to evaluate their condition and follow the doctor’s instructions.