Myopia
Conditions
Brief summary
This study will include patients who will undergo PRK in both eyes, for each patient each eye will be randomly allocated to one of 2 procedures: topography-guided ablation in one eye (group I) and Q-factor customized ablation in the other eye (group II). Alcon/Wavelight Light Laser Technolo¬gie (GmbH, Erlangen, Germany) will be used for photoablation. The wavelight Topolyzer (Wavelight AG, Erlan¬gen, Germany)and CSO Sirius scheimpflug camera combined with Placido corneal topography (CSO, Florence,Italy) will be used before and 1, 3 and 6 months after PRK. Refrac¬tive visual outcomes and corneal aberration changes will be compared between the two treatment modalities.
Interventions
PROCEDUREPRK
PRK using Alcon-Wavelight Excimer Laser EX 500
Sponsors
Kasr El Aini Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age more than 18 years * Myopia with up to -6.5 D with or without astigmatism up to -4.75 D
Exclusion criteria
* anterior segment abnormalities (ie, cataracts, corneal scarring) * basement membrane disease * history of recurrent corneal erosions * Schirmer's test less than 5 mm * established or forme fruste keratoconus * macular or retinal disease * current use of immunosuppressive therapy * autoimmune disease * pregnancy, and lactation
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| change in Q value | 1,3 and 6 months | assessed by topolyzer |
| change in visual acuity using snellen chart | 1 , 3 and 6 months postoperative | — |
| change in corneal wavefront aberrations | 1 , 3 and 6 months postoperative | assessed by topolyzer |
| change in Q value anterior at 6mm RMS, RMS of astigmatism, RMS of coma and RMS of spherical aberrations. Strehl ratio : Qvalue,RMS,strehl ratio by CSO Sirius scheimpflug | 1,3 and 6months | by CSO Sirius scheimpflug |
| change in total RMS | 1,3 and 6months | by CSO Sirius scheimpflug |
| change in strehl ratio | 1,3 and 6 months | by CSO scheimpflug |
| change in Postoperative spherical equivalent depending on manifest refraction after autorefractometer | 1 , 3 and 6 months postoperative | — |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| contrast sensitivity | 6 months | cambridge low contrast sensitivity |
| predictability | 6 months | eyes within 1.0 D of emmetropia |
| safety:ratio of mean preoperative decimal CDVA to mean postoperative decimal CDVA | 6 months | ratio of mean preoperative decimal CDVA to mean postoperative decimal CDVA |
| stability | 6 months | change of more than 0.5D over |
| efficacy:ratio of postoperative decimal UDVA to preoperative decimal CDVA | 6 months | ratio of postoperative decimal UDVA to preoperative decimal CDVA |
Countries
Egypt
Outcome results
None listed