# Corneal Refractive Therapy (CRT)

Corneal Refractive Therapy is a specific FDA approved overnight lens design within orthokeratology. Worn during sleep, it reshapes the cornea to correct nearsightedness, with the effect typically lasting around 24 hours per night of wear.

**In short:** A specific FDA approved overnight lens design. Approved for adults and children.

CRT is a branded lens design used within orthokeratology, approved by the FDA for overnight wear in both children and adults. Where general Ortho-K describes the technique, CRT describes one particular family of lens geometries used to deliver it.

In practical terms the patient experience is identical to any other overnight lens. It goes in at bedtime, comes out in the morning, and the correction holds for approximately 24 hours. What differs is the specific curve design and the fitting philosophy behind it.

Like all overnight correction, CRT is temporary and adjustable. Stopping lens wear returns the cornea to its previous shape. That reversibility is often the deciding factor for parents considering it for a child, because nothing is being committed to permanently.

## What is included

- Candidacy assessment and corneal topography
- CRT lens design and manufacture
- Diagnostic fitting on the eye
- Handling training and follow up schedule

## What this does not do

- Designed for nearsightedness. It does not address presbyopia.
- Correction lasts about a day, so nightly wear is required.
- Higher prescriptions may fall outside the design range.


## Questions and answers
**How long do the effects last?**

Approximately 24 hours per night of wear, which is why the lenses are worn nightly. Most wearers hold clear vision through a full waking day.

**Is CRT safe for children?**

CRT is FDA approved for use in both children and adults. As with any overnight lens the infection risk is managed through correct handling and kept follow up appointments.

**How do I know if I am a good candidate?**

Candidacy is decided from a comprehensive evaluation including corneal topography, because corneal shape matters as much as the prescription number.

**Is CRT different from Invisalens?**

Both are overnight orthokeratology. Invisalens is the practice's name for its whole overnight programme, and CRT is one specific FDA approved lens design that may be used within it.

## Related

- https://eyedoctorphoenixaz.com/ortho-k/what-is-ortho-k
- https://eyedoctorphoenixaz.com/ortho-k/invisalens
- https://eyedoctorphoenixaz.com/ortho-k/ortho-k-for-myopia-control

---## 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.