| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2693529 | Contact Lens and Anterior Eye | 2015 | 5 Pages |
•Corneal power has been measured with SimK and MPP provided by Sirius in eyes that underwent myopic PRK before and after surgery.•Refractive changes after surgery at corneal plane have been measured.•Refractive changes at corneal power with SimK and MPP variations before and after PRK have been compared.•SimK and MPP are not reliable in corneal power measuring after myopic PRK.
PurposeTo assess the accuracy of a combined Scheimpflug camera–Placido disk device (Sirius, CSO, Italy) in evaluating corneal power changes after myopic photorefractive keratectomy (PRK).MethodsTwo hundred and thirty-seven eyes of 237 patients that underwent myopic PRK with a refractive error, measured as spherical equivalent, ranging from −10.75 D to −0.5 D (mean −4.63 ± 2.21 D), were enrolled in this study. Corneal power evaluation using Sirius were performed before, 1, 3 and 6 months after myopic PRK. Mean simulated keratometry (SimK) and mean pupil power (MPP) were measured.Correlations between changes in corneal power, measured with SimK and MPP, and variations in subjective refraction, calculated at corneal plane, were evaluated using Pearson test at every follow up; differences between preoperative and postoperative data were evaluated with the Student paired t-test.ResultsA good correlation has been detected between the variations in subjective refraction measured at corneal plane 1, 3 and 6 months after myopic PRK and both SimK (R2 = 0.8463; R2 = 0.8643; R2 = 0.7102, respectively) and MPP (R2 = 0.6622; R2 = 0.5561; R2 = 0.5522, respectively) but corneal power changes are statistically undervalued for both parameters (p < 0.001).ConclusionsEven if our data should be confirmed in further studies, SimK and MPP provided by this new device do not seem to accurately reflect the changes in corneal power after myopic PRK.
