Effect of intracorneal ring segments on posterior corneal tomography in eyes with keratoconus

Abstract

Keratoconus is the most common type of ectatic corneal disease. It leads to visual impairment due to the resulting progressive myopia and irregular astigmatism. ICRS implantation is one of the known effective treatment modalities for visual improvement in keratoconus, by flattening of the central cornea and reduction of irregular astigmatism. Although the anterior corneal surface is the main refractive surface of the cornea, the posterior surface plays an important role especially in keratoconus. The magnitude of posterior corneal astigmatism in keratoconus is much higher than in normal corneas. Therefore, it has a significant contribution to the total corneal astigmatism and its effect should not be neglected. The aim of this study is to evaluate the effect of ICRS implantation on the posterior corneal surface and to correlate this effect with the visual outcome. This is a prospective, interventional case series study that assessed 46 eyes of 30 patients with keratoconus who underwent ICRS implantation. All patients were implanted with Kera rings (Mediphacos, Belo Horizonte, Brazil) of 5 mm diameter. The number of rings, arc length and segment thickness were tailored to each case.