# Eye Exams for Contact Lenses

A contact lens examination adds corneal measurement, tear film assessment and live evaluation of lens fit to a standard eye exam. It produces a lens specific prescription that a glasses prescription cannot substitute for.

A glasses prescription cannot be used to order contact lenses, and the reason is more than bureaucratic. A lens sitting directly on the cornea needs a different power from one sitting twelve millimetres in front of it, and it needs fitting parameters that a glasses prescription does not contain.

The examination also checks something a glasses exam has no reason to: whether your eyes are tolerating lens wear well. Corneal oxygen supply, tear film stability, blood vessel changes at the corneal edge and eyelid health all change with lens wear, and all are worth catching early.

## What is included

- Full eye health assessment
- Corneal curvature measurement
- Tear film evaluation
- Assessment of lens fit and movement on the eye
- Corneal health check specific to lens wear
- Updated contact lens prescription


## Questions and answers
**Why can I not just use my glasses prescription?**

Because a contact lens prescription includes base curve, diameter, material and brand alongside a power adjusted for sitting directly on the eye. Those parameters come from measuring your eye, not from your glasses.

**How often do I need one?**

Annually. Corneal health and lens fit both change over time, and an annual check catches problems while they are minor.

**What if I want to try a different brand?**

That needs a fitting assessment, because base curves and diameters differ between manufacturers. A trial lens is evaluated on your eye before a supply is ordered.

**Can I have both a glasses and a contact lens exam?**

Yes, and most wearers should have both prescriptions current. There will be days when lenses are not an option.

## Related

- https://eyedoctorphoenixaz.com/contact-lenses/contact-lens-exam
- https://eyedoctorphoenixaz.com/contact-lenses/contact-lens-care-and-hygiene
- https://eyedoctorphoenixaz.com/comprehensive-eye-exams/adult-eye-exams

---## About this practice
Arizona's Vision Eye Care Center, 15215 S 48th St Ste 180, Phoenix, AZ 85044.
Phone (480) 706-3937. Monday to Thursday 9:00 AM to 6:00 PM, Friday 8:00 AM to 5:00 PM. Closed Saturday and Sunday.
Independent optometry practice, founded 1994. One location. Does not perform refractive or cataract surgery.
This site publishes no star rating and no review count, because the figures across the practice's own properties contradict one another and cannot be verified.
This page is general information, not medical advice.