title: Outcomes of radiofrequency in advanced keratoconus.
abstract: OBJECTIVE
  To evaluate the use of radiofrequency energy to correct advanced keratoconus.
  
  
  METHODS
  Universidade Federal de Minas Gerais, Belo Horizonte, and Universidade de Ciências da Saúde de Alagoas, Maceió, Brazil.
  
  
  METHODS
  In this prospective comparative study, radiofrequency was applied to 25 eyes of 21 consecutive patients. One group comprised patients with a K-reading between 54.0 diopters (D) and 58.0 D; 8 thermal spots were placed at the 4.0 mm optical zone. The other group comprised patients with a K-reading greater than 58.0 D; 16 spots were applied at the 4.0 mm and 5.0 mm optical zones. The minimum follow-up was 18 months in all patients. Differences between preoperative and postoperative uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), manifest refraction, and K-readings were clinically and statistically evaluated.
  
  
  RESULTS
  At end of the 18-month follow-up, the mean BSCVA in the 8-spot group improved from 20/100 (0.71+/-0.25 logMAR) preoperatively to 20/40 (0.32+/-0.11 logMAR) and in the 16-spot group, from 20/200 (1.03+/-0.30 logMAR) to 20/60 (0.62+/-0.22 logMAR). The mean manifest refractive spherical equivalent (MRSE) improved from -7.70 D+/-5.20 (SD) preoperatively to -6.82+/-4.41 D after 18 months in the 8-spot group and from -11.33+/-6.70 to -8.38+/-5.12 D, respectively, in the 16-spot group. The mean best contact lens-corrected visual acuity was 20/30 (0.18+/-0.24 logMAR) in the 8-spot group and 20/40 (0.31+/-0.19 logMAR) in the 16-spot group. A dense corneal scar was seen in 1 patient in the 16-spot group at the 6-month follow-up.
  
  
  CONCLUSIONS
  Radiofrequency appeared safe for the treatment of advanced keratoconus. Contact lens fitting was stable in all cases.
authors.affiliation: Universidade de Ciências da Saúde de Alagoas, Maceió, Brazil. joaomlyra@hotmail.com
authors.forename: João Marcelo
authors.initials: JM
authors.lastname: Lyra
authors.forename: Fernando Cançado
authors.initials: FC
authors.lastname: Trindade
authors.forename: Daniela
authors.initials: D
authors.lastname: Lyra
authors.forename: Antônio
authors.initials: A
authors.lastname: Bezerra
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism* / Q000503:physiopathology; D019781:Corneal Topography; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D007640:Keratoconus / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D011446:Prospective Studies; D011846:Radio Waves; D012029:Refraction, Ocular / Q000502:physiology; D012780:Short-Wave Therapy / Q000379:methods*; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology
chemical_list: D003094:Collagen