Myopia and Astigmatism refractive Surgery in virgin eyes
Conditions
Interventions
Thirty-eight patients selected after complete ophthalmic examination will undergo refractive surgery for myopia and astigmatism (Lasik) with bilateral femtosecond laser, with custom asphericity ablati
Procedure/surgery
Q65.070
C11.744.636
C11.744.212
Sponsors
Hospital de Olhos - Oftalmax
Hospital de Olhos - Oftalmax
Eligibility
Inclusion criteria
Inclusion criteria: Patients of both sexes aged 20-35 years (avoiding possibly presbyopia patients), myopic with or without astigmatism, with stable refractive error for at least 1 year and visual acuity corrected away from 0.1 logMAR or better. The myopia may vary between -0.50 and -8.00 diopters (D) and the astigmatism between 0.00 and -3.00 cylindrical diopters (CD), with maximum spherical equivalent of 8.00D.
Exclusion criteria
Exclusion criteria: Patients with significant anisometropia, that is a refractive difference of 1 spherical diopter or 0.75 cylindrical diopters between the eyes, will be excluded from the study. Other exclusion criteria will be: presence of clinical signs of dry eye, abnormalities of the anterior segment - such as cataracts, scars or corneal neovascularization within 1.0 mm of the desired ablation zone, epithelial basement membrane disease, history of recurrent corneal erosions, progressive or unstable myopia, PAT (percentage of altered tissue) calculation above 35% of the corneal thickness at its finest point in the ablation calculation19,24, pachymetry below 500, suspected keratoconus in its subclinical or stablished form, macular or retinal disease, diagnosis of glaucoma or ocular hypertension, current use of systemic corticosteroids or immunosuppressive therapy, collagen diseases, vascular diseases, diabetes mellitus types I and II, pregnancy and breastfeeding. The patient who presents any type of intraoperative intercurrence will be excluded from the study.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The main variable to be studied is visual acuity without correction measured postoperatively. Eyes treated by topography-guided ablation (Contoura) should have a line-of-sight gain in visual acuity measurement greater than that of asphericity (Custom-Q);Both groups showed excellent results and did not show superiority in uncorrected visual acuity (UDVA)between eyes treated by Contoura and eyes treated by Custom-Q. In terms of methods’ difference, the average difference between Contoura and Custom-Q was 0,015 logMAR (Wald ?²(1) = 0.691, p-value = 0,406); therefore, we have lack of evidence regarding the difference between both methods across the time on the UDVA. | — |
Secondary
| Measure | Time frame |
|---|---|
| Measurement of total optical corneal aberrations, as measured by corneal tomography, should be smaller in eyes undergoing topography-guided treatment. There may also be a difference in the residual cylinder, as here lies the main difference in methods. In other items, it is likely that there is no difference.;Once again, we observed lack of evidences regarding the difference between both methods in all parameters. The unstandardized coefficient gives the difference between both methods after adjusting for baseline assessment. For example, the difference between Contoura and Custom-Q on CDVA is 0.007 logMAR after adjusting for baseline CDVA assessment. In terms of magnitude of difference, evaluated via standardized beta, among the six outcomes evaluated via linear regression, the largest difference between the methods was on RMS (?= 0,146), indicating that the both groups have a difference of 0,146 standard deviations. In the same way, the smallest difference between both methods, in absolute standardized effect size, was found at MRSE (?= -0.009). Important to note that both outcomes showed p-values superior to 0,05, indicating lack of evidence regarding the difference between both methods. Moreover, even in case of RMS, 0,146 standard deviation is a small difference in terms of effect size. | — |
Countries
Brazil
Contacts
Public ContactErmano Alves
Oftalmax
Outcome results
None listed