Yumna Busool Abu-Eta1,2, Achia Nemet3, Igor Vainer4, Michael Mimouni4, Tzahi Sela5, Gur Munzer5, Igor Kaiserman3,5. 1. Department of Ophthalmology, University Hospitals of Leicester NHS Trust, Leicester, UK. yumna.busool@gmail.com. 2. Department of Ophthalmology, Saint Vincent de Paul Hospital, Affiliated with The Faculty of Medicine, Bar-Ilan University, Azrieli Faculty of Medicine, Safed, Israel. yumna.busool@gmail.com. 3. Department of Ophthalmology, Barzilai Medical Center, Ashkelon and The Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheba, Israel. 4. Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel. 5. Care-Vision Laser Centers, Tel-Aviv, Israel.
Abstract
PURPOSE: To assess post-operative outcomes following photorefractive keratectomy (PRK) in patients with posterior corneal steepening compared to an age, gender and refraction matched control group. METHODS: A retrospective matched case-control study that analysed outcomes of PRK in eyes with posterior corneal steepening as shown by the Sirius tomography (Sirius, CSO, Italy), versus normal eyes. Both groups were age, gender and refraction matched. Data collected include: demographic data, pre-operative and post-operative refraction, uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), maximal ablation depth. Inferior-superior ratio, central corneal thickness (CCT), mean posterior keratometry (K), Baiocchi Calossi Versaci index for the front (BCVf) and back (BCVb) cornea, the symmetry index of front (SIf) and back (SIb) corneal curvature were assessed pre- and postoperatively. RESULTS: Overall, 89 study eyes and 954 normal myopic eyes were included. Compared to the control group, corneas with posterior steepening demonstrated significantly reduced CDVA (p < 0.0001 and p = 0.007) and lower CCT (p < 0.0001 and p = 0.03), before and following the operation, respectively. Pre-operative BCVf, BCVb, SIf and SIb were significantly higher in corneas with posterior steepening (p < 0.0001) and remained higher following the surgery except for BCVf. Ectasia occurred in one eye (1.1%). The safety and efficacy indices at 12 months were comparable for both groups. CONCLUSION: PRK on corneas with posterior steepening results in similar refractive outcomes compared to normal eyes, 1 year following the surgery. Keratectasia is a rare, however a possible complication.
PURPOSE: To assess post-operative outcomes following photorefractive keratectomy (PRK) in patients with posterior corneal steepening compared to an age, gender and refraction matched control group. METHODS: A retrospective matched case-control study that analysed outcomes of PRK in eyes with posterior corneal steepening as shown by the Sirius tomography (Sirius, CSO, Italy), versus normal eyes. Both groups were age, gender and refraction matched. Data collected include: demographic data, pre-operative and post-operative refraction, uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), maximal ablation depth. Inferior-superior ratio, central corneal thickness (CCT), mean posterior keratometry (K), Baiocchi Calossi Versaci index for the front (BCVf) and back (BCVb) cornea, the symmetry index of front (SIf) and back (SIb) corneal curvature were assessed pre- and postoperatively. RESULTS: Overall, 89 study eyes and 954 normal myopic eyes were included. Compared to the control group, corneas with posterior steepening demonstrated significantly reduced CDVA (p < 0.0001 and p = 0.007) and lower CCT (p < 0.0001 and p = 0.03), before and following the operation, respectively. Pre-operative BCVf, BCVb, SIf and SIb were significantly higher in corneas with posterior steepening (p < 0.0001) and remained higher following the surgery except for BCVf. Ectasia occurred in one eye (1.1%). The safety and efficacy indices at 12 months were comparable for both groups. CONCLUSION: PRK on corneas with posterior steepening results in similar refractive outcomes compared to normal eyes, 1 year following the surgery. Keratectasia is a rare, however a possible complication.