Post-op topography map predicts high curvature gradients

March 20, 2014

When predicting topographical change in corneal remodelling, the new curvature gradient map, acquired immediately after surgery, predicted change in tangential curvature over the subsequent 12 months in areas where initial tangential curvature was greatest.

When predicting topographical change in corneal remodelling, the new curvature gradient map, acquired immediately after surgery, predicted change in tangential curvature over the subsequent 12 months in areas where initial tangential curvature was greatest. When the curvature gradient was high, the surface curvature modification remained in progress months after surgery, according to researchers in Italy and the US.

Researchers from Humanitas Clinical and Research Centre, Rozzano, Italy; the Department of Surgical and Morphological Sciences, University of Insubria, Circolo Hospital, Varese, Italy; the Departments of Ophthalmology and Biomedical Engineering, The Ohio State University, Columbus, Ohio; and Studio Oculistico VinciEye, Milan, Italy, conducted a retrospective study of 32 eyes in 16 patients with myopia.

All of the patients underwent excimer ablation surgery with a postoperative high curvature gradient. The researchers compared the new curvature gradient map acquired immediately postoperatively to the tangential curvature difference map acquired between 1 and 12 months postoperatively. The patients’ corneas were divided into 12 regions for analysis, starting with four 90°-wide sectors centred on 0°, 90°, 180° and 270°. In addition, each of these sectors was divided into 3 subdivisions: central (radius 0 to 2.75 mm), paracentral (radius 2.75 to 3.25 mm) and peripheral (radius 3.25 to 4.5 mm). Linear regression analysis was performed by region.

The researchers found that the paracentral zone of the 90° sector (P = .0145; R2 = 0.1832) and both the central (P = .0034; R2 = 0.2522) and paracentral (P = .0452; R2 = 0.1271) zones of the 270° sector had significant relationships between the initial curvature gradient and curvature difference between 1 and 12 months postoperatively. The 270° sector showed the greatest average initial tangential curvature.

To view the abstract of this study visit the Journal of Refractive Surgery.

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