The Clinical Results of Intrastromal Corneal Ring Segment Implantation Using a Femtosecond Laser in Keratectasia

PURPOSE: To evaluate the clinical results of intrastromal ring segment (Keraring(R)) implantation using a femtosecond laser in patients with keratectasia. METHODS: Twenty eyes of 19 keratectatic patients (15 eyes of keratoconus and five eyes of post-LASIK keratectasia) who completed at least three months of postoperative follow-up were included in this study. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), spherical equivalent, keratometric value, corneal astigmatism, corneal higher order aberrations (HOA) and specular microscopy were determined or performed before and after surgery. In addition, intraoperative and postoperative adverse complications were recorded. RESULTS: UCVA improved in 13 out of 20 eyes (65%), and BSCVA improved in 16 out of 20 eyes (80%). At the postoperative examination there was no statistically significant reduction in the spherical equivalent with that observed at the examination before implantation. Conversely, there were statistically significant reductions in topographic mean K value and Sim K astigmatism, corneal total and coma-like HOA (p<0.05). On specular microscopy, there was no statistically significant difference between preoperative and postoperative endothelial cell density. There was one case of partial Descemet membrane detachment and one case of microperforation as a complication during surgery, which recovered over time without any treatment. CONCLUSION: Keraring(R) implantation appears to be an effective and safe procedure for improving visual acuity and stabilizing corneal refractive power in keratectactic patients.

Three Cases of Urrets-Zavalia Syndrome Following Deep Lamellar Keratoplasty (DLKP)

PURPOSE: To report three cases of Urrets-Zavalia syndrome after deep lamellar keratoplasty. CASE SUMMARY: A retrospective chart analysis of two men who underwent deep lamellar keraplasty after corneal chemical burns and one woman who was treated with deep lamellar keratoplasty due to lattice dystrophy was performed. To maintain the anterior chamber depth and prevent formation of a double anterior chamber after deep lamellar keratoplasty, air or gas (C3F8) was injected into the anterior chamber for all three cases. After injections of air or gas (C3F8) into the anterior chamber, pupillary blocks occurred and intraocular pressures increased. Afterwards, intraocular pressures were well-controlled, but the pupil remained irreversibly fixed and dilated despite the use of miotics. CONCLUSIONS: Urrets-Zavalia syndrome, a postoperative complication, was first reported in a patient who underwent penetrating keratoplasty for keratoconus. This syndrome can also occur after deep lamellar keratoplasty on rare occasions.