Abstract
Purpose: :
To evaluate the effectiveness of treatment of hyperopia and presbyopia with neutral pressure conductive keratoplasty (NPCK), a modified form of conductive keratoplasty which applies radiofrequency energy to the corneal periphery to produce collagen rearrangement, thereby steepening the central cornea, for the correction of mild to moderate spherical hyperopia.
Methods: :
Retrospective review of 20 consecutive eyes that underwent NPCK by one surgeon for the correction of hyperopia and/or presbyopia. The eyes were divided into 3 groups – Group 1 (n = 8): 8 spots in 8.0 mm optical zone (oz) for up to 1 diopter (D) of intended hyperopic correction; Group 2 (n = 7): 8 spots in 7.0 mm oz for up to 1.75 D of intended hyperopic correction; Group 3 (n = 5): 8 spots in 8 mm oz and 8 spots in 7 mm oz for up to 2.50 D of intended hyperopic correction. Average pre– and post treatment auto–keratometry (Auto–K) values were analyzed at 1, 3 and 6 months postop to determine the stability and effectiveness of NPCK and develop a treatment nomogram. Auto–K values were used to have a non–biased end point for data analysis.
Results: :
The change of average keratometry values was 0.71 ± 0.59 D (0.00 – 1.57) in Group 1 (8 spots in 8.0 mm oz), 0.91 ± 0.39 D (0.70 – 1.25) in Group 2 (8 spots in 7.0 mm oz), and 1.96 ± 0.33 D (1.62 – 2.50) in Group 3 (8 spots in 8 mm oz and 8 spots in 7.0 mm oz).
Conclusions: :
NPCK is an effective form of treatment for the correction of hyperopia and presbyopia. Predictable and effective outcomes were demonstrated in all 3 groups. NPCK offers greater effect with fewer treatment spots as compared to previous FDA studies of conventional conductive keratoplasty. Comparison with results by other surgeons and further follow will be evaluated and presented.
Keywords: refractive surgery • hyperopia • presbyopia