International Journal of Keratoconus and Ectatic Corneal Diseases

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VOLUME 7 , ISSUE 1 ( 2018 ) > List of Articles

ORIGINAL AND RESEARCH ARTICLE

The Potential Impact of Cone Eccentricity on Visual Outcomes in Inferior and Central Keratoconus Patients following Keraring Implantation: A Pilot Preliminary Study

Iraklis Vastardis, Aye Khine, Mohamed Elalfy, Samer Hamada, Georgios Perdikakis, Markus Kohlhaas, Zisis Gatzioufas

Keywords : Eccentricity, Kerarings, Keratoconus.

Citation Information : Vastardis I, Khine A, Elalfy M, Hamada S, Perdikakis G, Kohlhaas M, Gatzioufas Z. The Potential Impact of Cone Eccentricity on Visual Outcomes in Inferior and Central Keratoconus Patients following Keraring Implantation: A Pilot Preliminary Study. Int J Kerat Ect Cor Dis 2018; 7 (1):12-18.

DOI: 10.5005/jp-journals-10025-1154

License: CC BY-SA 3.0

Published Online: 01-06-2010

Copyright Statement:  Copyright © 2018; The Author(s).


Abstract

Aim: To evaluate possible correlation of cone eccentricity and visual acuity in inferior and central keratoconus patients following Keraring implantation for keratoconus. Materials and methods: A total of 19 eyes from an equal number of patients were analyzed in this preliminary pilot retrospective study. Two groups were formed, group I for inferior (n = 11) and group II for central keratoconus (n = 9). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometric readings, central corneal thickness, maximum keratometric distance from corneal apex (DKmax), and corneal thinnest point from corneal apex (DTh) were evaluated preoperatively and 6 months after the Keraring implantation. The DKmax and DTh were measured and from corneal apex to evaluate the eccentricity of the cone. Results: The CDVA and refractive cylinder reduction improved at 6 months postoperatively in both groups (t-test, p = 0.002, p < 0.0001 and p = 0.0007, p = 0.0017 respectively). Topography keratometric findings (Kmax difference) and spherical equivalent improved for group II but not for group I (t-test, p = 0.002, p = 0.005 and p = 0.85, p = 0.12 respectively). There was a high correlation between CDVA and corneal astigmatic reduction (p = 0.0283, correlation coefficient r = -0.7) and a negative relation in regression analysis (p = 0.0240, y = 0.2616 + - 0.1354 × + 0,03750 × 2, coefficient of determination R2 = 0.7115) for the central keratoconus but not for the inferior one. There was no correlation between the topography landmarks DKmax or DTh and CDVA and no statistical difference was found between them in t-test at 6 months. Conclusion: Both groups profited from a Keraring implantation in terms of CDVA, but a relation between corneal astigmatic reduction and CDVA after Keraring implantation at 6 months was found only in patients with central keratoconus. Clinical significance: This finding suggests that a visual acuity improvement in keratoconus patients is not only topographic and keratometric-related but also higher order aberration reduction-dependent. Bigger prospective studies that also evaluate corneal aberration reduction findings are needed to support our results.

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