Abstract
Purpose:
Outcome Analyisis of a combination of Intracorneal ring segment (ICRS) both Ferrara and Intacts, for tectonic and refractive correction of paracentral keratoconus.
Methods:
43 eyes of 33 patients with contact lens intolerance or progressive paracentral keratoconus underwent ICRS surgery and were followed for 1 at least 6 months. Patients were divided in two groups acording with the coincidence of axis of astigmatism and coma as Group I, +- 30° coincident, croissant shape and Group II, non coincident (30-75°), duck shape. Surgery were performed manually and ICRS were implanted at 6 mm of the optical axis: 150° Ferrara ICRS were placed temporal-inferiorly and 90° intacs were located nasal-superiory. Tectonic outcome were evaluated as a reduction of the keratometric (K) values: K minimal (Kmin) and K maximal (Kmax)).Visual outcome were measured as improve in uncorrected distance visual acuity (UDVA), best corrected visual acuity (CDVA), and refractive error (miopia and astigmatism) redcution (decimal scale). Data were processed with R-programing language for descriptive ans inference statistical análisis análisis
Results:
There were a significant (p<0.01) reduction of keratometric values in both gropus, specially in Kmax: Group 1: Kmax-pre 49.06 ± 0.4 to Kmax-post 46.37 ± 3.43). Group 2: Kmax-pre 51.25 ± 3.95 to Kmax-post 49.06 ± 3.53). Regarding VA there were a significative (p<0.01) in both gropus: Mean UDVA change in Group I from 0.19± 0.21 to 0.44± 0.33; Group II from 0.19 ± 0.16 to 0.51 ± 0.33. Mean DCVA change in Group I from 0.58 ± 0.30 to 0.62 ± 0.24; Group II from 0.57 ± 0.25 to 0.68 ± 0.25. Myopic and astigmatism components were highly reduced after ICRS implantation (P < 0.01). Myopia was reduced in Group I from -4.80 ± 2.97 to -1.94 ± 2.02 and Group II from -4.65 ± 2.23 to -2.22 ± 2.47. Astigmatism was reduced in Group I from 5.16 ± 2.46 to -2.68 ± 1.47. and Group II from 4.60 ± 0.83 to -3.60 ± 1.40. No intraoperative and postoperative complications occurred in these eyes.
Conclusions:
The combination of Ferrara and Intacs ICRS implantation archive good tectonic and refractive outcome in the care of patients with keratoconus. Nomograms for ICRS implantation should be changed and customized in order to archive standart refractive outcome.
Keywords: 574 keratoconus •
421 anterior segment •
494 degenerations/dystrophies