Most eye care professionals recommend that you have a comprehensive eye exam every one to two years, depending on your age, risk factors and whether you currently wear eyeglasses or contact lenses.
Children need regular eye exams to detect vision problems that may interfere with learning.
Routine eye exams are essential for children to be ready to learn in school, and experts say more than 80 percent of information children receive in classrooms is presented visually.
Children generally should have their first eye exam at 6 months of age, another exam at age three and again at the start of school. Risk-free children should then continue to have their eyes examined every two years until age 18.
Children with risk factors for vision problems may need their first eye exam earlier than 6 months of age and may need more frequent eye exams throughout childhood.
Examples of risk factors include:
1)History of premature birth or low birth weight
2)Infection of mother during pregnancy (examples: rubella, venereal disease, herpes, AIDS)
4)Turned or crossed eyes (strabismus)
5)Family history of eye disease
6)High refractive errors Physical illness or diseases
Also, children who currently wear eyeglasses or contact lenses should have annual eye exams.
Seniors need regular eye exams to avoid sight-threatening diseases.
To maintain a lifetime of healthy vision, adults ages 18 to 60 should have a comprehensive eye exam at least every two years. Older adults (age 61 and older) should have annual exams.
"At risk" adults should have more frequent exams. Risk factors for adults include:
1)A family history of eye disease (glaucoma, macular degeneration, etc.)
2)Diabetes or high blood pressure.
3)A visually demanding occupation or one that may pose hazards to the eyes.
4)Taking prescription or non-prescription drugs that may have visual or eye-related side effects.
5)Previous eye injuries or eye surgery (including cataract surgery)
If you have any doubts about how often you (or your children or parents) should have your eyes examined, ask your eye doctor.
Source from : https://www.allaboutvision.com/eye-exam/preparing.htm