Intacs for keratoconus.
OBJECTIVE
To evaluate the efficacy and safety of placement of Intacs in subjects with keratoconus.


METHODS
Retrospective, nonrandomized comparative trial.


METHODS
Intrastromal corneal ring segment implantation.


METHODS
Seventy-four eyes of 50 subjects (41 male and 9 female) were evaluated. The mean age of subjects in the study was 35 years, ranging from 20 to 73 years. Twenty-six subjects underwent single-eye treatment, and 24 subjects had both eyes treated.


METHODS
A modified Intacs procedure was performed on subjects with keratoconus. Pachymetry was measured at the incision site, and the incision was made at 66% of the corneal thickness. A thicker ring segment was typically placed inferiorly, and a thinner segment was placed superiorly on the basis of a refractive nomogram.


METHODS
Differences between preoperative and postoperative uncorrected visual acuity, best spectacle-corrected acuity, and spherical equivalent. Changes in irregular astigmatism were evaluated with the inferior-superior value from comeotopographic maps, and differences in refractive cylinder groups were studied.


RESULTS
Preoperative mean best-corrected logarithm of the minimum angle of resolution (LogMAR) visual acuity was 0.41 (20/50 - 1) (standard deviation [SD], +/-0.48), which improved to a postoperative mean of 0.24 (20/32 - 2) (SD, +/-0.31) (two lines of improvement). Preoperative mean uncorrected LogMAR visual acuity was 1.05 (20/200 - 2 1) (SD, +/-0.48), which improved to a mean of 0.61 (20/80-) (SD, +/-0.52) (four lines of improvement) at postoperative follow-up. Preoperative mean best-corrected LogMAR acuity in the corneal scarring group was 0.96 (20/200 + 2) (SD, +/-0.72), which improved to a mean of 0.54 (SD, +/-0.43) (20/63 - 2) (five lines of improvement). Uncorrected mean LogMAR acuity in the eyes with corneal scarring was 1.42 (20/400 - 4) (SD, +/-0.27), which improved to a mean of 1.03 (20/200 - 1) (SD, +/-73) (three lines of improvement). The mean spherical equivalent before surgery was -3.89 diopters (D) (SD, +/-5.16), which was reduced to a mean of -1.46 D (+/-4.11) at the postoperative follow-up.


CONCLUSIONS
Asymmetric Intacs implantation can improve both uncorrected and best spectacle-corrected visual acuity and can reduce irregular astigmatism in corneas with and without corneal scarring.
Boxer Wachler Vision Institute, Beverly Hills, CA 90210, USA. bbw@boxerwachler.com
Brian S
BS
Boxer Wachler
Jonathan P
JP
Christie
Naveen S
NS
Chandra
Brian
B
Chou
Tommy
T
Korn
Richard
R
Nepomuceno
D000328:Adult; D000368:Aged; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery; D001672:Biocompatible Materials; D003319:Corneal Stroma / Q000601:surgery*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019904:Polymethyl Methacrylate; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D012449:Safety; D014792:Visual Acuity / Q000502:physiology
D001672:Biocompatible Materials; D019904:Polymethyl Methacrylate