Top nicardipine Related Articles. 1  amlodipine Amlodipine besylate (Norvasc) is a drug that belongs to the drug class of calcium channel blockers (CCBs), and is prescribed for the treatment and prevention of angina (heart or chest pain) that results from coronary spasm and from exertion.
By age 3 or 4 years, most children are able to cooperate for subjective visual acuity testing using an eye chart. If a child is unable to cooperate for visual acuity testing at age 3, a second attempt should be made within 6 months, if the child is age 4, a second attempt should be made within one month.
Although measuring subjective phenomena has attendant problems, careful consideration of the goals of measurement and of the various potential biases in measurement should ease the burden of the investigator or research team in the development of new measures.