Intracorneal ring segment implantation in advanced Keratoconus.

PURPOSE: To compare the clinical outcomes of intracorneal ring segment (ICRS) implantation in eyes with advanced vs. mild/moderate keratoconus (KCN). METHODS: A retrospective analysis of 141 eyes of 111 patients with KCN who underwent ICRS implantation. Preoperative maximum keratometry (Kmax) was <57 diopters (D) in 70 eyes and >57 D in 71 eyes. Postoperatively, corrected distance visual acuity (CDVA), Kmax, and intraoperative and postoperative complications were assessed at 1 day, 1 month, and 1 year. RESULTS: Corneas with a preoperative Kmax >57 D experienced greater reduction in axial curvature after ICRS implantation than corneas with a preoperative Kmax <57 D (7.0 D vs. 5.5 D, p=0.005) and gained more Snellen lines of CDVA (3 vs. 1, p<0.001) by 1 year postoperatively. The incidences of the most prevalent complications (explantation, extrusion, and infectious keratitis) did not differ significantly between the two groups (p=0.29, p=0.99, p=0.98). CONCLUSIONS: The visual and topographic effects of ICRS implantation are greater in eyes with more advanced KCN, with no increase in the incidence of the most common complications.

Combined corneal wavefront-guided transepithelial photorefractive keratectomy and accelerated corneal collagen cross-linking following intracorneal ring segment implantation in management of moderate keratoconus.

PURPOSE: Keratoconus (KC) leads to gradual progressive loss of vision in young and adult patients. For the purpose of visual rehabilitation and for hindering KC progression in patients, we designed this study. The main aim of this study is to help the KC patients to improve and stabilize their vision. METHODS: This prospective consecutive uncontrolled study includes 36 eyes of 36 patients with moderate degree of KC. All patients underwent combined wavefront-guided transepithelial photorefractive keratectomy (TPRK) and accelerated corneal collagen cross-linking (ACXL) after intracorneal ring segment (ICRS) implantation. Different measures will be evaluated at baseline, after ICRS implantation, and at one, 3, 6, and 12 months after combined (TPRK and ACXL). These measurements are uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, and higher-order aberrations (HOAs) based on (Sirius, Schwind) tomography. RESULTS: There were significant improvements in logMAR (UDVA and CDVA) and reduction in sphere, manifest cylinder, MRSE, maximal keratometry, and mean keratometry after ICRS implantation in the first stage. After TPRK and ACXL as the second stage, there were significant improvements in visual acuity of both logMAR UDVA and CDVA. Reduction in refractive outcomes, including MRSE, sphere, and manifest cylinder. All corneal indices including steep, flat, mean, and maximal keratometries had been decreased. Furthermore, there were significant improvements in the final root mean square, HOAs, and coma aberrations from baseline. CONCLUSION: In moderate KC, triple therapy of ICRS implantation followed by combined TPRK and ACXL appears to be a safe and effective approach. This approach provides an improvement in visual acuity, refraction, corneal indices, and HOAs. These improvements were maintained for 1 year postoperatively. It also halts KC progression.

The number of intracorneal ring segments in asymmetric and central cones.

BACKGROUND: To compare the results of single versus double intracorneal ring segment (ICRS) (KeraRing) implantation in keratoconus with respect to different cone locations. METHODS: Twenty-two eyes of 18 patients with totally asymmetric cones (20-80% or 0-100% distribution along steep axis) were implanted with single ICRS (Group 1), 38 eyes of 32 patients with central or partially asymmetric cones (50-50% or 40-60% distribution along steep axis) were implanted with double ICRS (Group 2), at a depth of 80% of the site of implantation, in channels created with femtosecond laser device. All patients had uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively) of ≤ 0.3 Snellen lines. RESULTS: In both groups, patients had median UDVA and CDVA gain of 3 Snellen lines (P > 0.05). Postoperative improvement in indices of vertical asymmetry and height decentration in Group 1; simulated keratometry, corneal astigmatism and anterior corneal asphericity values in Group 2 were greater (P < 0.05). A total of 10 eyes (45.5%) in Group 1 were recommended double ring implantation by the manufacturer's nomogram, but underwent single ICRS implantation and achieved visual, refractive, tomographic outcomes comparable to that in Group 2, although corneal cylindrical correction was less and final topographic astigmatism was greater. CONCLUSION: Double ICRS implantation seems to be superior in terms of keratometry, corneal astigmatism and anterior corneal asphericity improvement. Single ICRS implantation in totally asymmetric cones seems to provide satisfactory visual, refractive and tomographic results, similar to double ICRS implantation in central and partially asymmetric cones, by inducing central shift of the cone.

[Excimer laser in keratoconus management]. / Le laser excimer dans la prise en charge du kératocône.

Visual rehabilitation in keratoconus is a challenge, notably because of the significant irregular astigmatism and optical aberrations that it induces. Many surgical techniques have been developed in addition to, or in the case of failure of, spectacles and rigid gas permeable contact lenses: intracorneal ring segments, intraocular lenses, excimer laser and, as a last resort, keratoplasty. Excimer laser photoablates the cornea, allowing remodeling of its surface. There are various treatment modes (wavefront-optimized, wavefront-guided and topography-guided), allowing performance of a customized treatment if needed. Its use in keratoconus has been described since the 2000s, alone or in combination with other procedures. For example, the combination of photoablation and corneal cross linking, a technique that increases corneal rigidity and in so doing can slow or even stop the progression of keratoconus, proved its efficacy and safety in many studies, and various protocols have been described. A triple procedure, including intracorneal ring segments, excimer laser and cross linking, has also given some very promising results in progressive keratoconus, providing a significative improvement in visual acuity and topographic data. The combination of excimer laser and intraocular lenses remains a poorly explored lead that might provide some satisfactory results. The objective of this review is to summarize the recent data on excimer laser in keratoconus management.

Visual rehabilitation in moderate keratoconus: combined corneal wavefront-guided transepithelial photorefractive keratectomy and high-fluence accelerated corneal collagen cross-linking after intracorneal ring segment implantation.

BACKGROUND: To investigate the effects of combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) after intracorneal ring segment (ICRS) implantation in patients with moderate keratoconus. METHODS: Medical records of 23 eyes of 23 patients undergoing combined tPRK and CXL after ICRS implantation were retrospectively analyzed. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, higher-order aberrations (HOAs), and corneal biomechanical properties were evaluated before and after ICRS implantation, and at 1, 3, and 6 months after combined tPRK and CXL. RESULTS: There were significant improvements in final logMAR UDVA and logMAR CDVA, and reductions in sphere, MRSE, and all corneal indices from baseline. Significant improvements in logMAR UDVA and reductions in sphere, MRSE, maximal keratometry, keratometry at the apex, mean keratometry, and keratoconus index were noted after ICRS implantation. After tPRK and CXL, significant improvements in logMAR UDVA and logMAR CDVA, and reductions in cylinder and all corneal indices were observed. There were significant improvements in final root mean square HOAs and coma aberrations from baseline, but no changes from baseline after ICRS implantation. Significant reductions in final radius and deformation amplitude from baseline were noted. CONCLUSIONS: Combined tPRK and accelerated CXL after ICRS implantation in moderate keratoconus appears to be a safe and effective treatment, providing an improvement in visual acuity, corneal indices, and HOAs. TRIAL REGISTRATION: retrospectively registered (identification no. NCT03355430 ). Date registered: 28/11/2017.