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Removal of INTACS for myopia
Thomas E Clinch1, Michael A Lemp, Gary N Foulks
1University Ophthalmic Consultants of Washington, DC 20016, USA.
Objective:
To evaluate the safety and efficacy of the removal of INTACS.
Design:
Subgroup analysis from a nonrandomized comparative interventional trial.
Participants:
Four hundred fifty-two patients with best spectacle-corrected visual acuity of 20/20 or better and myopia (1.0-3.5 diopters [D]) were enrolled in the U.S. Food and Drug Administration clinical trials of INTACS. Forty-six eyes among a total of 684 underwent INTACS removal.
Intervention:
INTACS removal.
Methods:
Safety and efficacy of INTACS removal was assessed by comparison of results from preoperative and 3-month postremoval visits. Safety was assessed by maintenance of preoperative best spectacle-corrected acuity and induction of astigmatism (measured by manifest refraction). Efficacy was assessed by comparison of mean spherical equivalent measured by both manifest and cycloplegic refraction, as well as percentage of eyes within +/- 0.5 D and +/- 1.0 D of baseline values. A subset of 27 patients completed a prospective questionnaire assessing the frequency of six visual symptoms (glare, halos, double vision, photophobia, night vision difficulties, and fluctuating vision).
Main Outcomes Measures:
Best spectacle-corrected visual acuity, manifest refraction, and cycloplegic refraction.
Results:
Forty-one of 46 patients' eyes that had undergone INTACS removal had reached the 3-month postremoval visit. Of these eyes, 73% (30 of 41) had returned to within +/- 0.5 D and 97% (40 of 41) to within +/- 1.0 D of baseline spherical equivalent as measured by manifest refraction. With respect to astigmatism, 88% (36 of 41) had returned to within +/- 0.5 D and 100% (41 of 41) to within +/- 1.0 D of preoperative value. No patient had a loss of best spectacle-corrected acuity of more than 2 lines, with equal numbers of eyes having a loss or gain of 1 line (nine eyes) and 2 lines (one eye). For most eyes, INTACS removal was associated with a substantial reduction in the six types of visual symptoms; however, in some eyes (up to 15%) symptoms that had not been detected preoperatively were noted after INTACS removal.
Conclusions:
INTACS removal was not associated with a loss (> 2 lines) of best spectacle-corrected visual acuity or induction (> 1 D) of astigmatism or myopia. INTACS removal was associated with a reversal to preoperative values in most cases.