Videokeratography in conductive keratoplasty

PURPOSE: We used EyeSys videokeratography to evaluate corneal shape changes induced by conductive keratoplasty, a procedure that utilizes radio frequency energy to alter corneal shape to correct hyperopia. METHODS: Follow-up data were available for 19 eyes (out of 24 eyes of 13 patients). Preoperative spherical hyperopia ranged from +0.75 to +3.25 D with astigmatism <0.75 D. Manifest refractive spherical equivalent refraction (MRSE), uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), topographical parameter predicted corneal acuity (PCA), corneal uniformity index (CU Index), regular astigmatism, total astigmatism, average simulated keratometry (Avg Sim K), effective refractive power, and asphericity were measured preoperatively and at 6 and 12 months postoperatively. RESULTS: Twelve months postoperatively, mean PCA, CU Index, and BSCVA were maintained at preoperative levels. Mean UCVA (LogMAR) improved from 0.53 ± 0.21 to 0.10 ± 0.19 (P<.05) with a mean MRSE change from +1.62 ± 0.76 D to -0.06 ± 0.84 D (P<.05) from preoperative to 12 months postoperative. Mean asphericity increased +0.044 ± 0.24 D (P>.05), mean Avg Sim K increased 1.88 ± 0.72 D (P<.05), mean effective refractive power increased 1.71 ± 0.79 D (P<.05), mean cylinder (cycloplegic refraction) increased 0.19 ± 0.36 D (P<.05), mean regular astigmatism increased 0.25 ± 0.49 D (P>.05), and mean irregular astigmatism decreased 0.01 ± 0.13 D (P>.05) from preoperative to 12 months after conductive keratoplasty. CONCLUSIONS: Avg Sim K and effective refractive power changes support the refractive results; 12-month postoperative maintenance of BSCVA, PCA, and CU Index suggest the procedure is safe. Conductive keratoplasty induced a slight regular astigmatism in some eyes, which decreased with time. The increase in mean corneal asphericity indicated possible induction of central and peripheral cornea changes.