Franziska Löffler1, Myriam Böhm1, Michael Herzog1, Kerstin Petermann1, Thomas Kohnen2. 1. Department of Ophthalmology, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany. 2. Department of Ophthalmology, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany. Electronic address: kohnen@em.uni-frankfurt.de.
Abstract
PURPOSE: To analyze the effect of penetrating femtosecond laser-assisted keratotomy (pFLAK) during laser lens surgery on anterior and posterior corneal astigmatism and total corneal refractive power (TCRP) astigmatism (CAant, CApost, CATCRP) measured with Scheimpflug tomography. DESIGN: Prospective, interventional case series. METHODS: This institutional study included 27 eyes of 23 patients (aged 65 ± 8 years) with low-to-moderate CATCRP determined with Scheimpflug tomography (Pentacam HR; Oculus, Wetzlar, Germany) after penetrating femtosecond laser-assisted keratotomy (pFLAK) and laser lens surgery. The CAant, CApost, and CATCRP were determined before and 1 and 3 months after surgery. Vector analysis according to the Alpins method was used to calculate surgically induced astigmatism (SIA). RESULTS: The mean preoperative CAant (0.97 ± 0.30 diopter [D]) was significantly reduced to 0.63 ± 0.34 D (P < .001). SIAant was 0.71 ± 0.37 D. The CApost showed no significant change, from preoperative 0.26 ± 0.12 D to 0.26 ± 0.10 D postoperatively (P = .625). In line with this finding, SIApost was low (0.12 ± 0.07 D). The CATCRP showed similar results as CAant. CONCLUSION: pFLAKs planned according to Scheimpflug-based CATCRP result in a significant reduction of the CAant and CATCRP, but do not affect the posterior corneal curvature significantly, as measured by Scheimpflug tomography. Further research is required to develop a new valid nomogram for laser-assisted lens surgery.
PURPOSE: To analyze the effect of penetrating femtosecond laser-assisted keratotomy (pFLAK) during laser lens surgery on anterior and posterior corneal astigmatism and total corneal refractive power (TCRP) astigmatism (CAant, CApost, CATCRP) measured with Scheimpflug tomography. DESIGN: Prospective, interventional case series. METHODS: This institutional study included 27 eyes of 23 patients (aged 65 ± 8 years) with low-to-moderate CATCRP determined with Scheimpflug tomography (Pentacam HR; Oculus, Wetzlar, Germany) after penetrating femtosecond laser-assisted keratotomy (pFLAK) and laser lens surgery. The CAant, CApost, and CATCRP were determined before and 1 and 3 months after surgery. Vector analysis according to the Alpins method was used to calculate surgically induced astigmatism (SIA). RESULTS: The mean preoperative CAant (0.97 ± 0.30 diopter [D]) was significantly reduced to 0.63 ± 0.34 D (P < .001). SIAant was 0.71 ± 0.37 D. The CApost showed no significant change, from preoperative 0.26 ± 0.12 D to 0.26 ± 0.10 D postoperatively (P = .625). In line with this finding, SIApost was low (0.12 ± 0.07 D). The CATCRP showed similar results as CAant. CONCLUSION: pFLAKs planned according to Scheimpflug-based CATCRP result in a significant reduction of the CAant and CATCRP, but do not affect the posterior corneal curvature significantly, as measured by Scheimpflug tomography. Further research is required to develop a new valid nomogram for laser-assisted lens surgery.