To compare visual outcomes, corneal astigmatism, and keratometric readings in patients with progressive keratoconus undergoing intrastromal corneal ring implantation (ICRSI) only and in combination with ultraviolet A riboflavin mediated corneal collagen crosslinking (CXL).
Methods
In this retrospective comparative study, there were 2 groups of keratoconus patients. Group 1 consisted of only ICRSI patients. Group 2 consisted of combined ICRSI-CXL patients. Preoperative and postoperative uncorrected distance visual acuity (UCDVA) and best-corrected distance visual acuity (BCDVA), spherical error, cylindrical error, and mean keratometry were compared.
Results
The study evaluated 166 eyes of 121 patients with a mean age of 24.74 years. The UCDVA improved from 0.24 to 0.37 in group 1 and from 0.24 to 0.42 in group 2 at the last visit. The BCDVA improved from 0.34 to 0.62 in group 1 and from 0.31 to 0.67 in group 2. Spherical error decreased from −5.05 D to −1.65 D in group 1 and from −4.82 D to −1.52 D in group 2. Cylindrical error decreased from −6.06 D to −3.47 D in group 1 and from −5.66 D to −3.20 D in group 2. Mean keratometry values decreased from 51.89 D to 47.96 D in group 1 and from 50.89 D to 46.91 D in group 2. p Value was ≥0.05 in group comparisons. Ring explantation due to corneal melting was applied in 3 eyes.
Conclusions
Both combined ICRSI-CXL and ICRSI-only groups experienced favorable outcomes, without statistical difference in any studied effect of both treatment strategies.
KrachmerJ.H., FederR.S., BelinM.W.Keratoconus and related noninflammatory corneal thinning disorders. Surv Ophthalmol1984; 28: 293–322.
3.
CaporossiA., MazzottaC., BaiocchiS., CaporossiT.Long-term results of riboflavin ultraviolet a corneal collagen cross-linking for keratoconus in Italy: the Siena eye cross study. Am J Ophthalmol2010; 149: 585–93.
4.
WollensakG., SpoerlE., SeilerT.Riboflavin/ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol2003; 135: 620–7.
5.
WollensakG., SpoerlE., ReberF., SeilerT.Keratocyte cytotoxicity of riboflavin/UVA-treatment in vitro. Eye2004; 18: 718–22.
6.
KohlhaasM., SpoerlE., SchildeT., UngerG., WittigC., PillunatL.E.Biomechanical evidence of the distribution of cross-links in corneas treated with riboflavin and ultraviolet A light. J Cataract Refract Surg2006; 32: 279–83.
7.
SpörlE., HuhleM., KasperM., SeilerT.[Increased rigidity of the cornea caused by intrastromal cross-linking] [German]. Ophthalmologe1997; 94: 902–6.
8.
WollensakG.Crosslinking treatment of progressive keratoconus: new hope. Curr Opin Ophthalmol2006; 17: 356–60.
9.
TorquettiL., BerbelR.F., FerraraP.Long-term follow-up of intrastromal corneal ring segments in keratoconus. J Cataract Refract Surg2009; 35: 1768–73.
10.
ErtanA., KamburoğluG.Intacs implantation using a femtosecond laser for management of keratoconus: comparison of 306 cases in different stages. J Cataract Refract Surg2008; 34: 1521–6.
11.
ZareM.A., HashemiH., SalariM.R.Intracorneal ring segment implantation for the management of keratoconus: safety and efficacy. J Cataract Refract Surg2007; 33: 1886–91.
12.
AlióJ.L., ShabayekM.H., ArtolaA.Intracorneal ring segments for keratoconus correction: long-term follow-up. J Cataract Refract Surg2006; 32: 978–85.
13.
KubalogluA., SariE.S., CinarY., KoytakA., KurnazE., OzertürkY.Intrastromal corneal ring segment implantation for the treatment of keratoconus. Cornea2011; 30: 11–7.
14.
CoskunsevenE., JankovMRII, HafeziF., AtunS., ArslanE., KymionisG.D.Effect of treatment sequence in combined intrastromal corneal rings and corneal collagen crosslinking for keratoconus. J Cataract Refract Surg2009; 35: 2084–91.
GrewalD.S., BrarG.S., JainR., SoodV., SinglaM., GrewalS.P.Corneal collagen crosslinking using riboflavin and ultraviolet-A light for keratoconus: one-year analysis using Scheimpflug imaging. J Cataract Refract Surg2009; 35: 425–32.
17.
ColinJ.European clinical evaluation: use of Intacs for the treatment of keratoconus. J Cataract Refract Surg2006; 32: 747–55.
18.
SansanayudhW., BaharI., KumarN.L.. Intrastromal corneal ring segment SK implantation for moderate to severe keratoconus. J Cataract Refract Surg2010; 36: 110–3.
19.
ShabayekM.H., AlióJ.L.Intrastromal corneal ring segment implantation by femtosecond laser for keratoconus correction. Ophthalmology2007; 114: 1643–52.
20.
Raiskup-WolfF., HoyerA., SpoerlE., PillunatL.E.Collagen crosslinking with riboflavin and ultraviolet-A light in keratoconus: long-term results. J Cataract Refract Surg2008; 34: 796–801.
21.
DaxerA., MahmoudH., VenkateswaranR.S.Intracorneal continuous ring implantation for keratoconus: one-year follow-up. J Cataract Refract Surg2010; 36: 1296–302.
22.
AsriD., TouboulD., FourniéP.. Corneal collagen cross-linking in progressive keratoconus: multicenter results from the French National Reference Center for Keratoconus. J Cataract Refract Surg2011; 37: 2137–43.
23.
PiñeroD.P., AlióJ.L., El KadyB.. Refractive and aberrometric outcomes of intracorneal ring segments for keratoconus: mechanical versus femtosecond-assisted procedures. Ophthalmology2009; 116: 1675–87.
24.
AlióJ.L., ToffahaB.T., PiñeroD.P., KlonowskiP., JavaloyJ.Cross-linking in progressive keratoconus using an epithelial debridement or intrastromal pocket technique after previous corneal ring segment implantation. J Refract Surg2011; 27: 737–43.
25.
KollerT., MrochenM., SeilerT.Complication and failure rates after corneal crosslinking. J Cataract Refract Surg2009; 35: 1358–62.
26.
FerrerC., AlióJ.L., MontañésA.U.. Causes of intrastromal corneal ring segment explantation: clinicopathologic correlation analysis. J Cataract Refract Surg2010; 36: 970–7.
