Abstract
Purpose :
To determine if the value of the posterior corneal curvature in the calculation of the IOL produces a lower residual astigmatism in patients with toric IOL implantation after phacoemulsification compared with the standard IOL calculation.
Methods :
An observational, ambispective and analytical study was carried out. Patients with toric IOL implant after phacoemulsification were included, Patients were divided into 2 groups, in group 1 the calculation of the IOL was made taking into account only the values of the anterior corneal surface, that were measured with an optical biometer, in group 2 the calculation of the IOL was made including the values of the anterior and posterior corneal surface that were measured with a rotating Scheimpflug camera, the preoperative and postoperative data (cylinder, keratometries, axial length, anterior chamber depth, IOL cylinder) of both groups were compared, the continuous variables were analyzed with the Student's t-test; the categorical variables, with χ2 test.
Results :
The study population includes 103 participants, of whom 66 were women and 37 men; the mean age was 64 years.
Group 1 included 69 participants, with an average residual astigmatism of 0.67 diopters (SD 0.55) [range 0-3], average pre-surgical flat keratometry was 43.39 diopters (SD 1.65) [range 38.08-46.89], average pre-surgical curve keratometry was 45.36 diopters (DE 1.76) [range 40.66-49.68]. Group 2 included 34 participants, with an average residual astigmatism of 0.64 diopters (SD 0.39) [range 0-1.5], average pre-surgical flat keratometry was 42.12 diopters (SD 1.69) [range 40.1-48.36], average pre-surgical curve keratometry was 45.32 diopters (DE 1.73) [range 42.3-49.9]. Pre-surgical astigmatism had a difference between groups of 0.15 diopters (P value of 0.5). Calculation of the IOL cylinder had a difference between groups of 0.04 diopters (P value of 0.8). Residual astigmatism difference between both groups was 0.03 diopters (P value of 0.8).
Conclusions :
The outcomes of both groups studied showed a low residual astigmatism, without presenting a statistically significant difference, although the standard deviation and range were lower in group 2 .We found that including the posterior corneal curvature in the calculation of the toric IOL also offers good results in terms of residual astigmatism compared to standard IOL calculation.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.