Comparison of Visual, Tomographic, and Biomechanical Outcomes of 360 Degrees Intracorneal Ring Implantation With and Without Corneal Crosslinking for Progressive Keratoconus: A 5-Year Follow-up

Abstract

Purpose: To evaluate the long-term (5 years) results of 360 degrees intracorneal ring (ICR) implantation with and without corneal crosslinking (CXL) in patients with progressive keratoconus (KCN). Method: This historical cohort study was performed on 35 eyes with progressive KCN, which was randomly divided into 2 groups. Fourteen patients were implanted only with ICR, and 21 patients with KCN were treated with ICR plus CXL simultaneously. Uncorrected distance visual acuity (UCDVA), corrected distance visual acuity (CDVA), and refractive components were collected from patients' medical records. The biomechanical properties of patients were measured using the Corvis ST (Oculus, Inc, Weltzar, Germany). Corneal topography and aberrometry parameters were also recorded from the Pentacam HR device (Oculus). Results: Both UCVA and CDVA increased in both groups after ICR implantation; however, this improvement was more significant in the ICR plus CXL group (P = 0.002 and P = 0.001, respectively). The mean improvement of CDVA in patients with ICR implantation with and without CXL was 0.56 ± 0.67 and 0.33 ± 0.61, respectively. A comparison of the long-term postoperative Tomographic and Biomechanical Index between 2 groups showed a better result in the ICR plus CXL group (P = 0.012). Topographic findings of the anterior corneal surface (flat-K, steep-K, mean-K, and astigmatism) after surgery were significantly better than before surgery in both groups (P < 0.05). Conclusions: Although ICR implantation alone might halt the KCN progression with acceptable visual, topographic, and biomechanical outcomes, the combination of ICR and CXL has an adjuvant and synergistic effect, especially in long-term follow-up.

Seven-year follow-up of a novel 360-degree implant (annular intracorneal inlay) plus accelerated corneal cross-linking: A case study

“…Notwithstanding, the risk of this complication has been considerably decreased by introducing the accelerated CXL (ACXL) protocol. 1 The current case report is the first report that represents the postoperative clinical outcomes of a patient diagnosed with stage II KCN who underwent annular intracorneal inlay plus CXL procedure in the left eye after 7 years.…”

“…Notwithstanding, the risk of this complication has been considerably decreased by introducing the accelerated CXL (ACXL) protocol. 1…”

“…Recent studies have shown the effectiveness of intrastromal corneal ring (ICR) implants and their combination with other treatment modalities in managing KCN patients. [1][2][3] Annular intracorneal inlay (AICI) is a novel continuous 360-degree ICR that could be effective as a sole treatment modality in progressive KCN. 4 The AICI is composed of Hexafocon A material that its biocompatibility was confirmed in an animal study on rabbits.…”

“…4 Corneal crosslinking (CXL) is an effective and minimally invasive treatment option to halt the progression of KCN. 1 CXL plus is a modified method of standard CXL in which CXL is combined with other surgical options like ICR implant for better visual outcomes. 2 The original protocol of CXL is known as the Dresden protocol and might induce phototoxicity reactions because of its prolonged irradiation of UV-A over the cornea.…”

Continuous Intracorneal Ring Implantation in Keratoconus: Efficacy, Predictive Factors, and Complications

“…Nonetheless, numerous other studies with follow-up periods of 1, 2, 3 and 5 years demonstrated stable refractive and keratometry outcomes with marginal improvement of HOAs beyond the first year. 9,14,15,[37][38][39] Furthermore, this work is also limited by the lack of its consideration of HOAs and qualitative photic phenomena, which play an important role in patients' quality of life. 15,32 Only one study to date has published any patient-centered outcomes such as satisfaction scores.…”