TY - JOUR
T1 - Anatomical and Visual Effects of the MyoRing Implantation Measured by the ABCD Keratoconus Grading System
AU - Sedaghat, Mohammad Reza
AU - Momeni-Moghaddam, Hamed
AU - Belin, Michael W.
AU - Akbarzadeh, Reyhaneh
AU - Sakhaee, Mehdi
AU - Armanfar, Fatemeh
AU - Shahri, Farkhondeh
AU - Akhavan Rezayat, Amir
N1 - Publisher Copyright:
Copyright © 2019 Contact Lens Association of Ophthalmologists, Inc. Unauthorized reproduction of this article is prohibited.
PY - 2020/1/1
Y1 - 2020/1/1
N2 - Objective:To assess the anatomical changes produced by implantation of the complete intracorneal ring (MyoRing; DIOPTEX, GmbH, Linz, Austria) on the different corneal anatomical layers as measured by the ABCD keratoconus staging system 6 months after operation.Methods:Seventeen eyes of 17 keratoconic patients implanted with MyoRing using the femtosecond laser were assessed preoperatively and postoperatively. Distance uncorrected visual acuity and distance corrected visual acuity (DCVA), refraction, and Scheimpflug tomography with Pentacam HR were determined for each patient. The 4 ABCD parameters were recorded, which include the anterior and posterior radius of curvature from a 3.0-mm optical zone centered on the thinnest point (TP) (A & B, respectively), the thinnest corneal thickness (C), and DCVA (D).Results:Statistically significant improvement (preoperatively vs. postoperatively) in the DCVA (0.40±0.21 vs. 0.67±0.20 in decimal notation, P=0.001) associated with significant flattening effect was observed in both anterior (6.02±0.40 vs. 7.18±0.54 mm, P<0.001) and posterior (4.49±0.41 vs. 4.66±0.40 mm, P=0.001) radius of curvature. There was no significant change in the corneal thickness at the TP (P=0.981). The largest magnitude of change occurred on the anterior surface as measured by the "A" parameter. The average ABCD keratoconus staging before MyoRing implantation was A4B4C2D2 and changed to A1B4C2D1 6 months after ring implantation.Conclusion:Despite the placement of MyoRings in the posterior one-third of the cornea, the greatest changes in curvature occurred on the anterior corneal surface. The ABCD classification and staging system allows for a differential assessment of the different anatomical layers and may prove useful in better understanding of the geometric (structural) and functional changes after MyoRing implantation, as well as with other corneal procedures.
AB - Objective:To assess the anatomical changes produced by implantation of the complete intracorneal ring (MyoRing; DIOPTEX, GmbH, Linz, Austria) on the different corneal anatomical layers as measured by the ABCD keratoconus staging system 6 months after operation.Methods:Seventeen eyes of 17 keratoconic patients implanted with MyoRing using the femtosecond laser were assessed preoperatively and postoperatively. Distance uncorrected visual acuity and distance corrected visual acuity (DCVA), refraction, and Scheimpflug tomography with Pentacam HR were determined for each patient. The 4 ABCD parameters were recorded, which include the anterior and posterior radius of curvature from a 3.0-mm optical zone centered on the thinnest point (TP) (A & B, respectively), the thinnest corneal thickness (C), and DCVA (D).Results:Statistically significant improvement (preoperatively vs. postoperatively) in the DCVA (0.40±0.21 vs. 0.67±0.20 in decimal notation, P=0.001) associated with significant flattening effect was observed in both anterior (6.02±0.40 vs. 7.18±0.54 mm, P<0.001) and posterior (4.49±0.41 vs. 4.66±0.40 mm, P=0.001) radius of curvature. There was no significant change in the corneal thickness at the TP (P=0.981). The largest magnitude of change occurred on the anterior surface as measured by the "A" parameter. The average ABCD keratoconus staging before MyoRing implantation was A4B4C2D2 and changed to A1B4C2D1 6 months after ring implantation.Conclusion:Despite the placement of MyoRings in the posterior one-third of the cornea, the greatest changes in curvature occurred on the anterior corneal surface. The ABCD classification and staging system allows for a differential assessment of the different anatomical layers and may prove useful in better understanding of the geometric (structural) and functional changes after MyoRing implantation, as well as with other corneal procedures.
KW - Complete intracorneal ring segment
KW - Corneal tomography
KW - Keratoconus
KW - MyoRing
KW - Pentacam
KW - Staging
UR - http://www.scopus.com/inward/record.url?scp=85076446596&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85076446596&partnerID=8YFLogxK
U2 - 10.1097/ICL.0000000000000595
DO - 10.1097/ICL.0000000000000595
M3 - Article
C2 - 30913096
AN - SCOPUS:85076446596
SN - 1542-2321
VL - 46
SP - 52
EP - 56
JO - Eye and Contact Lens
JF - Eye and Contact Lens
IS - 1
ER -