PURPOSE: To analyze the outcomes of intracorneal ring segment (ICRS) implantation for the treatment of keratoconus based on preoperative visual impairment. DESIGN: Multicenter, retrospective, nonrandomized study.METHODS: A total of 611 eyes of 361 keratoconic patients were evaluated. Subjects were classified according to their preoperative corrected distance visual acuity (CDVA) into 5 different groups: grade I, CDVA of 0.90 or better; grade II, CDVA equal to or better than 0.60 and worse than 0.90; grade III, CDVA equal to or better than 0.40 and worse than 0.60; grade IV, CDVA equal to or better than 0.20 and worse than 0.40; and grade plus, CDVA worse than 0.20. Success and failure indices were defined based on visual, refractive, corneal topographic, and aberrometric data and evaluated in each group 6 months after ICRS implantation.RESULTS: Significant improvement after the procedure was observed regarding uncorrected distance visual acuity in all grades (P < .05). CDVA significantly decreased in grade I (P < .01) but significantly increased in all other grades (P < .05). A total of 37.9% of patients with preoperative CDVA 0.6 or better gained 1 or more lines of CDVA, whereas 82.8% of patients with preoperative CDVA 0.4 or worse gained 1 or more lines of CDVA (P < .01). Spherical equivalent and keratometry readings showed a significant reduction in all grades (P £ .02). Corneal higher-order aberrations did not change after the procedure (P ‡ .05).CONCLUSIONS: Based on preoperative visual impairment, ICRS implantation provides significantly better results in patients with a severe form of the disease. K ERATOCONUS IS AN ECTATIC DEBILITATING corneal disorder characterized by a progressive corneal thinning that results in corneal protrusion, irregular astigmatism, and decreased vision. 1 A variety of options have been described for the management of this pathologic condition, such as rigid gas-permeable contact lenses, 2 corneal collagen cross-linking, 3 intracorneal ring segment implantation, 4-11 or keratoplasty. 12 In a number of studies intracorneal ring segments (ICRS) have been demonstrated to be effective in improving visual acuity and reducing the refractive error and the mean keratometry in selected cases of keratoconic eyes. 4-11 Such a positive therapeutic effect is considered to be based on the induction of a remodeling of the corneal anterior and posterior surface's topography, which improves the optical quality of the cornea and reduces the optical aberrations, with consequent improvement in best-corrected visual acuity. [4][5][6][7][8][9][10][11] Although in the healthy cornea, the sectorial arcuate addition to the corneal local volume caused by these implants at the corneal midperiphery induces a flattening of the central cornea in an arc-shortening effect, with the consequence of a decrease in myopic spherical equivalent attributable to the overall reduction in the optical power of the cornea, 13 such corneal modeling effect may be different in structurally abnormal corneas such as in keratoco...

Intrastromal corneal ring segment implantation in keratoconus patients provided long-term improvement of the refractive and topographic status. There was no correlation between the amount of individual changes in the mean K reading and patient age.

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No author has a financial or proprietary interest in any material or method mentioned.

To evaluate both refractive and biometry results of presbyopic refractive lens exchange (RLE) with trifocal intraocular lens (IOL) implantation in eyes previously submitted to corneal laser vision correction (LVC).

The grading system based on visual limitation was consistently represented by differences in CDVA loss, SE, and delta K. A high amount of tissue removed by the refractive procedure was associated with greater corneal biomechanical destabilization, increased corneal steepening, and a worse prognosis.

Laser in situ keratomileusis for primary compound myopic astigmatism with high cylinder (>3.00 D) performed using a fast-repetition-rate excimer laser with optimized aspheric profiles and cyclotorsion control was safe, effective, and predictable and did not cause significant induction of HOAs.

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