Abby El-ShafeiDr. Penny Asbell

Ophthalmology Dept. Mount Sinai School of Medicine

Corneal Refractive Therapy(CRT)

• CRT is a method for temporarily correcting Myopia through lenses that are worn overnight to reshape

the cornea

• Allows users to forgo glasses or contacts the next morning

Myopia • “Nearsightedness” is a condition where a person cannot see distant objects

clearly without glasses• This results from spending

a lot of time on computers, watching

television, and reading books

Corneal Epithelium

• Layer of cells that cover the surface of the cornea

Flurophotometry• A useful clinical method that measures the levels

of fluorescein in the eye to determine corneal epithelial permeability in which the Fluorotron

Master™ Diopters

A measurement of the power of a lens

Purpose

• To investigate whether extended use of CRT lenses has a

significant impact on the health of the cornea through the use of

fluorophotometry

• Extended use of CRT lenses will not significantly affect corneal permeability

Hypothesis

Methods

1. Obtained Approval from Review Board

2. Put up Flyers around the Mount Sinai Hospital and the surrounding neighborhood

3. Screening Sessions for qualification( 18 patients with refractive errors between -0.5 to - 4.0 diopter

4. Full length eye exam to see health before the use of CRT lenses

5. Day of Fitting: baseline readings taken by the Fluorotron Master

Methods Continued

6. Washed eyes with standard Saline after twenty minutes

7. Two post wash scans were taken of each eye8. Peak corneal florescence values were

measured by fluorophotmetry (indicated epithelial permeability

9. Subsequent scans of the cornea taken one day, one

week, one month, and three months after the initial fittings

10. Compared pre-fitting values to changes

Results

• After nightly use of CRT– Post CRT incorrected visual acuity

was 20/20 or better in 15 of 18 patients by day 7

Conclusion• CRT is effective in correcting myopic

refractive errors

Future Studies

This study is ongoing and longer follow up data will be analyzed

Acknowledgements

• Dr. Penny Asbell

• Dr. Elvin Yildiz

• Mount Sinai School of Medicine

• Dr. Sat Bhattacharya

• Harlem Children Society

• HCS Staff

References 1. Swarbrick, HA. Corneal Response to Orthokeratology.

Optom Vis Sci. 1998;75:773. 2. Ladage, P. What does Overnight Lens Wear Do to the Corneal

Epithelium?: Is Corneal Refractive Therapy Different?. Eye and Contact Lens 2004;30:194-197.

3. Paragon Vision Sciences, Paragon CRT FDA Professional Fitting and Information Booklet. June 2002, page 5.

4. Walline et al The Current state of Corneal Reshaping Eye & Contact Lens 2005 (31)5: 209-214, 2005

5. Watt K, Swarbrick HA. Microbial keratitisin overnight orthokeratology: review of the first 50 cases. Eye Contact Lens 2005; 31: 201–208.

6. Eef van der Worp et al Orthokeratology: An Update Optometry in Practice Vol 7 (2006) 47–60

7. Walline et al The Current state of Corneal Reshaping Eye & Contact Lens 2005 (31)5: 209-214, 2005

8. Eef van der Worp et al Orthokeratology: An UpdateOptometry in Practice Vol 7 (2006) 47–60

9. Lang, Jacob O.D.; Rah, Marjorie J. O.D., Ph.D., F.A.A.O. Adverse Corneal Events Associated With Corneal Reshaping: A Case Series Eye Contact Lens. 2004 Oct;30(4):231-3; discussion 242-3