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Ahmed El-Massry, Khalid Rashid ,†Seham Saad, Ihab Osman Department of Ophthalmology, Alexandria Faculty of Medicine, Alexandria, Egypt†Professor Khalid Rashid passed away on January 9, 2021.Correspondence: Ahmed El-MassryDepartment of Ophthalmology, Alexandria Faculty of Medicine, Champollion Street, El-Khartoum Square, El Azareeta Medical Campus, Alexandria, 21131, EgyptTel +20 122 215 2435Email ahmad.elmassry@gmail.comPurpose: To assess the results of simultaneously performed femtosecond laser–assisted Keraring intrastromal corneal ring–segment insertion and corneal collagen cross-linking for the treatment of keratoconus.Patients and Methods: In this retrospective, noncomparative, interventional study, 30 eyes of 24 progressive-keratoconus patients of both sexes aged 18– 36 years old with poor best-corrected visual acuity (BCVA) and intolerance to contact lenses were included. All patients had been subjected to complete preoperative and postoperative ophthalmological examinations — unaided VA, BCVA, refraction, Pentacam, and contrast sensitivity examinations at 3-month, 6-month, and 1-year follow-ups.Results: Mean unaided VA had changed significantly from 0.649± 0.239 logMAR preoperatively to 0.514± 0.222 (P=0.014), 0.419± 0.162 (P< 0.001), and 0.379± 0.142 (P< 0.001) logMAR at the three follow-up visits, respectively. Mean BCVA had changed significantly from 0.326± 0.144 logMAR preoperatively to 0.231± 0.140 (P=0.006) at 1-year follow-up. Mean spherical equivalent refraction had decreased significantly at 6-month (P=0.0298) and 1-year follow-up (P=0.0081). Mean steep keratometry (K2) had also significantly reduced from 51.89± 3.81 D to 49.87± 4.57 D (P=0.034) at 6 months and 49.40± 4.39 D (P=0.011) at 1 year. Mean refractive and keratometric astigmatism had significantly decreased at all follow-up visits.Conclusion: At 1-year follow-up, keraring intrastromal corneal ring–segment insertion assisted by femtosecond laser performed simultaneously with corneal collagen cross-linking resulted in an improvement in visual, refractive, and topographic outcomes, which may suggest it is an effective treatment of keratoconus.Keywords: keratoconus, corneal collagen cross-linking, Pentacam, ICRS

AIM: To evaluate the short-term clinical outcomes of Ferrara rings in keratoconus using an optimized nomogram developed after several years of research and retrospective analysis of clinical data. METHODS: This prospective longitudinal non-comparative clinical trial evaluated 88 eyes of 88 patients (age 18-62y) with keratoconus diagnosis from two Spanish centers. Ferrara ring segment (AJL Ophthalmic) implantation was performed in all cases, using the mechanical procedure in 25 eyes (28.4%) and a femtosecond laser-assisted procedure in 63 eyes (71.6%). The ring segments implanted in each case were selected using a new optimized nomogram that considered variables such as anterior corneal asphericity and astigmatism or the discrepancy among astigmatism and coma orientations. Visual, refractive, corneal topographic, aberrometric, and pachymetric changes after surgery were evaluated during a 3-month follow-up. RESULTS: The implants induced a significant refractive change as well as an improvement in uncorrected (UDVA) and corrected distance visual acuity (CDVA; P

Purpose: To assess potential differences between central and eccentric cones in the aberrometric corneal profile and in visual and keratometric outcomes 6 months after intracorneal ring segment (ICRS) implantation for keratoconus. Methods: This study compared two groups consisting of 12 patients each, with central or eccentric keratoconus who were treated with femtosecond laser-assisted Keraring implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, keratometric readings and higher order aberrations (HOAs) including high order aberrations root mean square (HOARMS), coma, spherical aberration and trefoil were measured preoperatively and 6 months after ICRS implantation. Results: Trefoil and spherical aberration were significantly reduced after ICRS implantation compared to preoperative values in eccentric keratoconus (Trefoil, p = 0.0049; Spherical aberration, p < 0.0001). In central keratoconus spherical aberration was reduced not significantly after ICRS implantation compared to preoperative values ( p = 0.087). Coma showed a significant reduction in central ( p = 0.0001) and in eccentric keratoconus ( p = 0.0001). The reduction of spherical aberration in central keratoconus was significantly positively correlated to improvement in UDVA (Pearson’s correlation coefficient, r = −0.66; p = 0.02). In eccentric keratoconus there was a significant positive correlation between reduction of trefoil and improvement in UDVA (Spearmans R, r = −0.69; p = 0.01). Conclusion: Patients both with central and eccentric keratoconus benefit from ICRS implantation. Specifically, our data provide a slightly higher gain in visual performance for eccentric cones 6 month after ICRS implantation, which is accentuated by a greater reduction in spherical aberration and trefoil. Improvements in UDVA are positively correlated with reductions in HOAs.

Background The corneal cross-linking procedure has been proven to be an effective method to treat and stabilize keratoconus progression, but early vision rehabilitation is still needed in patients. Aim The aim was to compare the results of the combined CXL and intrastromal corneal ring segment implantation procedure to that of the cross-linking-alone procedure in terms of visual acuity, refraction, and some corneal topographic parameters in keratoconic patients. Design This was a prospective, comparative, and interventional study. Patients and methods This study was carried out on 44 keratoconic patients (60 eyes) of both sexes who ranged from 18 to 36 years. Thirty eyes were subjected to the CXL-alone procedure and 30 eyes were subjected to the combined procedure. Measurements were performed in all patients preoperatively and at 3, 6 months, and 1 year postoperatively including unaided visual acuity, best-corrected visual acuity, refractive, and topographic outcomes. Results Through the entire study period, both procedures were safe and effective in treating and stabilizing keratoconus progression. Furthermore, the combined group showed additional improvements over the CXL group for the following: UDVA at 3 months (P=0.0028), best-corrected visual acuity at 1 year (P=0.011), refractive and keratometric astigmatism at all follow-up visits and corneal asphericity at 3 months (P=0.013) and 6 months (P=0.0221) of follow-up. No severe intraoperative or postoperative complications were observed during the entire study period in either group. Conclusions The combined procedure is safe and effective for earlier improvement of visual and refractive outcomes in addition to the corneal stabilizing effect.

To evaluate the progression of keratoconus in 932 eyes of 659 patients through visual, refractive and topographic data after intracorneal ring segment (ICRS) implantation.Retrospective review of 659 patients who underwent ICRS (Intacs®) implantation for keratoconus between September 1997 and November 2017. Demographics, preoperative and postoperative uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) in LogMAR, corneal topography parameters (thinnest pachymetry, Kmax), central corneal pachymetry and total follow-up time were evaluated. Statistical analysis was performed using IBM SPSS Statistics 24.0 for windows.Nine hundred and thirty-two eyes of 659 patients, with a mean age of 30.41 years (range 11-76 years), were evaluated. Mean total follow up time was 3.02 years. Forty-one eyes had a total follow up of over 10 years. Both UCVA and BCVA improved significantly after ICRS implantation (P0.01). Only 18 eyes (2.66% of eyes of patients under 35 years of age) were found to have progression of keratoconus based on postoperative topographic data (Mean age 23.00 years, 55.6% female, total follow-up 2 to 10 years) CONCLUSION: ICRS implantation showed long-term improvement and stability in visual and topographic results in a large case series of patients with keratoconus. Only a minimal rate of progression was detected in young patients. However, further prospective studies need to be conducted to better define predictability of postoperative visual outcomes and progression.

Purpose: To assess signs of dry eye syndrome in keratoconic eyes following intracorneal ring segment (ICRS) implantation. Patient and methods: Twenty eyes of 20 consecutive patients with keratoconus were assessed for tear film changes following ICRS implantation at 6 months postoperatively. Evaluated parameters included tear osmolarity, non-invasive tear breakup time test (NI-BUT test) and Schirmer test I and II before and after treatment. Results: No significant changes were found with respect to osmolarity, Schirmer I and II ( p = 0.9, p Conclusion: Our results suggest that implantation of ICRS does not result in a significant change in tear film osmolarity, or tear film volume nor improves the tear film stability.

Objective To analyze the changes in corneal biomechanical parameters of keratoconic eyes with and without intracorneal ring segment (ICRS) implants after 1 year of corneoscleral contact lens (CScL) wear. Methods Seventy-four eyes of 74 patients were divided into three groups: healthy subjects (29 eyes, control group), and 2 groups of subjects with keratoconic eyes (one group of 20 eyes with ICRS implants and one of 25 eyes without them), which were fitted with CScL. Corneal hysteresis (CH), corneal resistance factor (CRF), and corneal-compensated intraocular pressure (IOPcc) were evaluated before fitting CScL and after 1 year of CScL wear. In addition, endothelial cell count (ECC) and central corneal thickness (CCT) were also recorded. Results Corneal biomechanical parameters were lower in keratoconic corneas than in healthy corneas. Keratoconic eyes with ICRS implants had lower values than eyes without them for CH (mean±SD, 8.09±1.29 vs. 8.63±1.5 mm Hg, respectively, P=0.120), CRF (6.99±1.38 vs. 8.37±1.52 mm Hg, respectively, P=0.03), and also for CCT and ECC. Data for IOPcc were similar in all groups. After 1-year wearing CScL, no statistically significant differences in corneal biomechanical parameters were registered in any of the groups (all P>0.05), although slight differences (0.13-0.27 mm Hg) were found. Conclusion The viscoelasticity properties of the cornea did not change significantly when wearing corneoscleral contact lenses for 1 year, and therefore, these lenses seem to be safe and healthy and are a reasonable alternative option for keratoconus management.

PURPOSE To report visual, refractive, and corneal aberrations after implantation of a new asymmetric intracorneal ring segment (ICRS). METHODS This was a prospective, multicenter clinical study including 30 eyes of 26 patients with keratoconus. All cases were implanted with an ICRS, named the VISUMRING (VR), which had an arc length of 353 degrees and 2 asymmetric sections that can be customized in base width, length, and thickness. Ophthalmic evaluation included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, topography, and anterior corneal aberrations using the Sirius System (CSO, Firenze, Italy). Mean follow-up period was 14.7 ± 7.9 months. RESULTS Significant improvement of both UDVA and CDVA was observed after 1 year. UDVA improved from 0.08 ± 0.22 to 0.22 ± 0.16 and CDVA from 0.24 ± 0.29 to 0.43 ± 0.18 (P = 0.01). A significant reduction of more than 7 D in the spherical equivalent from -12.38 ± 3.77 D to -5.00 ± 3.26 D (P < 0.05) was noted 1 year after the procedure. In terms of higher-order aberrations, a slight reduction that was not statistically significant in the higher-order and coma-like aberrations was noted at 1 year from 4.32 and 3.82, to 4.12 and 3.55, respectively. Regarding complications, 5 of the 30 cases needed to have the VR explanted throughout the follow-up period due to severe corneal melting. CONCLUSIONS VR ICRS improves vision and refraction and induces major corneal flattening in patients with keratoconus. Further design enhancement is needed to increase the reduction of the asymmetric corneal aberrations and reduce the extrusion rate.

Purpose: To evaluate the visual quality results when fitting a corneo-scleral contact lens (CScL) after intracorneal ring segment (ICRS) implantation for keratoconus management. Methods: Twenty-seven eyes of 27 patients with keratoconus underwent ICRS implantation and had CScL fitted as their visual quality was unsatisfactory with their spectacles or contact lenses. Patients received a complete eye examination, refraction and visual acuity assessment, anterior eye biomicroscopy, ocular fundus examination, corneal topographic analysis, endothelial-cell count, and visual quality assessment using contrast sensitivity and aberrometry tests. A diagnostic trial set was used in the fitting process, and patients were assessed according to a standardised methodology, including subjective visual quality and comfort, and contact lens usage time. The follow-up period was one year. Results: After fitting CScL, log-MAR visual acuity values improved significantly in relation to the best spectacle-corrected vision (0.22 +/- 0.17 vs 0.00 +/- 0.12; p < 0.001). Total high-order aberrations decreased 33% (2.62 +/- 1.31 vs 1.75 +/- 1.81 pm; p < 0.009) and the spatial frequencies of contrast sensitivity all improved (all p < 0.05). Furthermore, 70.37% of patients reported high ratings of subjective visual quality (favourable and very favourable) and prolonged usage times (11.78 +/- 3.93 h). After wearing CScL for one year, no adverse ocular effects or clinically relevant changes in corneal parameters, visual quality, comfort ratings or usage time were found. Conclusion: This CScL appears to be an alternative reasonable option for keratoconic eyes with ICRS placement, providing an improvement in subjective visual quality.

PURPOSE: To assess epithelial corneal remodeling by anterior segment optical coherence tomography (AS-OCT) after intracorneal ring segments (ICRS) implantation in keratoconic eyes. METHODS: This prospective observational study included patients with keratoconus receiving ICRS of different arc lengths according to their tomographic pattern. AS-OCT and corneal topography (Scheimpflug camera) were performed before and 1, 3, and 6 months after surgery. Corneal pachymetry mapping was performed and total corneal and epithelial thicknesses (3-mm central and 16 points on 6-mm zone) were measured over the pupil center using AS-OCT. Topographic parameters were also assessed. RESULTS: A total of 68 keratoconic eyes were analyzed (Amsler-Krumeich stages 1 to 4) in four groups of 17 eyes: 210° ICRS, 320° ICRS, double 160° ICRS, and single 160° ICRS. Corneal pachymetry mapping revealed that epithelial thickness increased significantly in the internal zones juxtaposed to the ICRS without smoothing during the postoperative period ( P < .05). Mean maximum epithelial thickness increased from 67 ± 6 to 79 ± 7 µm for 210° ICRS, 66 ± 9 to 82 ± 4 µm for 320° ICRS, 63 ± 6 to 78 ± 7 µm for double 160° ICRS, and 62 ± 5 to 77 ± 5 µm for single 160° ICRS ( P < .0001). Significant epithelial thickening at the apex of the cone was observed in all groups ( P < .05). CONCLUSIONS: Significant epithelial thickening occurs after ICRS implantation adjacent to the ICRS to compensate for the ridge created with a thickening of epithelium over the cone due to regularization of the stromal surface. [ J Refract Surg . 2021;37(6):404–413.]

BackgroundTo compare the results of single versus double intracorneal ring segment (ICRS) (KeraRing) implantation in keratoconus with respect to different cone locations.MethodsTwenty-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.ResultsIn 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 ConclusionDouble 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.

Purpose:The implantation of intracorneal ring segments represents an effective and safe therapeutic option for visual improvement in patients with keratoconus. The presence of corneal opacities is considered an exclusion criterion for this operation.Methods:This is a retrospective cohort study of six eyes of six keratoconus patients at Queen Victoria Hospital, East Grinstead, UK, between January 2012 and December 2016. Femtosecond laser-assisted intracorneal ring segment implantation was performed in six eyes with apical corneal haze. Preoperative and postoperative visual acuity, keratometry readings, as well as corneal pachymetry were compared at 6-month follow-up.Results:Uncorrected visual acuity (UCVA) [LogMAR] improved significantly from median 1.05 [95% confidence interval (CI): 0.83–0.13] preoperatively to 0.9 (95% CI: 0.63–1.00) at 6 months postoperatively ( p = 0.03). Corrected visual acuity (CDVA) also improved significantly from median 0.75 (95% CI: 0.43–1.00) preoperatively to 0.4 (95% CI: 0.23–0.50) at 6 months postoperatively ( p = 0.03). Keratometric readings, K-max (diopters) and K-mean (diopters), decreased significantly from 54.5 and 47.85 preoperatively to 53.45 and 46.42 postoperatively, respectively ( p = 0.03). Corneal pachymetry showed no significant changes postoperatively.Conclusion:The results of this study show that the presence of apical haze should not exclude the implantation of intracorneal ring segments in patients with keratoconus.

Purpose: To compare VA outcomes in patients with advanced keratoconus wearing SCL or after ICRS or DALK. In addition, determine the percentage of complimentary treatments after ICRS and DALK, and which of these was fitting a SCL, and final visual acuity (f-VA) results. Methods: Retrospective case series analyzed 55 eyes with advanced keratoconus fitted with SCL, or after ICRS or a DALK between 2010 and 2018. The variables analyzed were sex, age, UDVA, CDVA, SEQ, K-readings, and f-VA after complimentary treatments. Results: Twenty-eight eyes underwent a DALK, 14 were fitted with a SCL, and other 13 underwent ICRS insertion. Patients after DALK and after ICRS showed statistically significant improvement in UDVA and CDVA after surgery, with no difference between these groups. Patients fitted with SCL showed statistically higher CDVA improvement when compared to ICRS. After DALK and ICRS, respectively, nine eyes (32.14%) and seven eyes (53.85%) were fitted with SCL. Comparison between f-VA with SCL in three groups showed that the best result was achieved in DALK + SCL, with statistically significant difference to only SCL. Conclusion: We showed that the CDVA of eyes fitted with SCL without any surgical treatment was statistically better than CDVA of eyes after ICRS insertion. After DALK and ICRS insertion, many patients needed a complimentary treatment to improve CDVA. The most chosen treatment was fitting a SCL. After this, all eyes showed statistically significant improvement in f-VA, with statistically better results for DALK + SCL when compared to SCL fitted in advanced keratoconus without any surgical treatment.

The short-term safety and efficacy of intracorneal ring segment (ICRS) implantation in keratoconus eyes of children are investigated in this study. A retrospective interventional case series study including a total of 33 keratoconus eyes (age 8 to 17 years) that had undergone ICRS (Keraring segments, Mediphacos) implantation was conducted. Information about visual, refractive, pachymetric, corneal topographic and aberrometric, and corneal endothelial changes during a 3-month follow-up were extracted and analysed. A significant improvement was observed in logMAR corrected distance visual acuity (p = 0.005), combined with a statistically significant reduction in keratometric readings (p &lt, 0.001). A reduction in the magnitude of corneal astigmatism of &ge, 1 D was observed in 52.8% of eyes. No significant changes were observed in corneal endothelial density (p = 0.317). Significant changes were found in the anterior vertical coma component (p = 0.002) as well as in the spherical aberration of the posterior corneal surface (p = 0.004). Only two relevant complications were described: one corneal microperforation with penetration of the ring segment into the anterior chamber (1 eye, 2.8%), and a case of ring extrusion (1 eye, 2.8%). ICRS implantation in children keratoconus eyes allows a reduction of corneal astigmatism, irregularity, and aberrations, leading to a significant visual improvement.

Purpose: To report the visual and refractive outcomes of sequential intracorneal ring segment (ICRS) and toric phakic intraocular lens (IOL) insertion for visual rehabilitation in keratoconus. Methods: A retrospective interventional cohort study was performed through the Corneoplastics unit and Eye Bank, Queen Victoria Hospital, East Grinstead, United Kingdom. Results: 14 eyes of 12 patients had sequential ICRS and phakic IOL implantation for visual rehabilitation of keratoconus between June 2014 and February 2018. After at least 6 months follow-up, the number of eyes with an uncorrected distance visual acuity (UDVA) of 20/40 UDVA or better increased from zero (0%) to 10 (71%). 12 (85.7%) eyes achieved a post-operative UDVA equal to or better than the pre-operative corrected distance visual acuity (CDVA). The number percentage of eyes with a CDVA of 20/40 or better increased from 3 (31%) to 14 (100%). The mean final spherical equivalent improved from −4.07 to −0.17 ( p ⩽ 0.001). The mean refractive astigmatism magnitude improved from 4.76D to 1.23D ( p = 0.002). Seven (50%) eyes had 1.0D or less of refractive astigmatism post-operatively. Conclusion: In this cohort of eyes with keratoconus, sequential ICRS and phakic IOL implantation resulted in excellent visual and refractive outcomes after at least 6 months.

Purpose To compare the efficacy of implanting a single Keraring segment according to a novel Q‐value‐based nomogram (QN) to that of segment implantation according to the manufacturer's standard nomogram (SN), for keratoconus treatment. Methods This was a prospective, randomized controlled trial of 104 patients (104 eyes) with Amsler‐Krumeich grade 1 or 2 keratoconus, and type 1 or 2 cone asymmetry determined according to manufacturer's classification. They were randomly distributed into two groups: group A patients (n = 52) underwent Keraring implantation according to the SN, and group B patients (n = 52) underwent implantation of a single (210° arc‐length) Keraring segment according to the QN. Both treatments were combined with accelerated transepithelial cross‐linking, and follow‐up was 6 months. Main outcome measures were preoperative and postoperative visual acuity, subjective refraction and corneal topography. Results At postoperative month 6, group B exhibited statistically significantly higher values of mean uncorrected distance visual acuity (UDVA), sphere, K2, K‐average, K‐max and Q‐anterior (p = 0.02, 0.01, 0.002, 0.001, 0.0001 and 0.03, respectively) compared to that of group A. However, group A exhibited better refractive cylindrical improvements (p = 0.04). In group A, we documented spontaneous extrusion of one Keraring segment. Conclusion Single 210° arc‐length segment implantation using our objective QN was more efficacious for keratoconus treatment than using the subjective SN. The nomograms were comparable when the Q‐anterior value was >−1.00; however, the QN was superior to the SN when the Q‐anterior value was ≤−1.00. The QN yielded greater postoperative UDVA and smoother corneal remodelling than did the SN for treatment of grade 1 and 2 keratoconic eyes.

Background Keratoconus, the most common primary corneal ectasia, is a bilateral asymmetric corneal degeneration accompanied with local corneal thinning and occurs mostly in the inferior and central part of the cornea, it usually causes high myopia and irregular astigmatism which results in poor quality of vision. Based on disease severity, many treatment modalities exist including glasses and contact lenses for mild to moderate disease, while corneal graft preserved for more advanced disease. In advent of alternative treatments, intrastromal ring implantation have been introduced which improves visual acuity and optical aberrations and also corrects refractive errors and mean keratometric data, anterior segment Optical cohehernce Tomography epithelial mapping is anew modality to assess epithelial thickness. Objective: To investigate epithelial thickness changes in keratoconic patients before and after intracorneal ring segment implantation using AS OCT. Methods: Thirty eyes with early to moderate keratoconus were included in this prospective interventional case series study which has been conducted at patients from Ain shams university hospitals, after the approval of the research ethical committee in the Faculty of Medicine, Ain Shams University between March to October. All cases underwent a Complete ophthalmological examination before surgery. the examination included Visual acuity assessment and Best corrected visual acuity. Slit Lamp Biomicroscopy examination with fundus examination through dilated pupil using D lens & Corneal Topography, Anterior segment Optical cohehernce Tomography Epithelial mapping(zeiss). Results: we found that epithelial thickness showing statistically significant change comparing pre and post operative epithelial mapping especially in certain areas in the map,area ( _ ),( _ ) mm. Conclusion: There is increase in epithelium thickness in keratoconic corneas after intracorneal ring segment implantation to compensate for stromal irregularities in patients with keratoconus.

Purpose: To evaluate the visual, refractive, topographic, pachymetric, and biomechanical outcomes after intracorneal ring segment implantation in corneas with post-LASIK ectasia. Methods: Retrospective longitudinal study enrolling 26 eyes of 22 patients with post-LASIK ectasia and undergoing intracorneal ring segment implantation (KeraRing®, Mediphacos) using a 60-kHz femtosecond laser (IntraLase®, IntraLase Corp.) for corneal tunnelization. Visual, refractive, anterior, and posterior corneal topographic (Pentacam HR, Oculus), pachymetric, and corneal biomechanical changes (Ocular response Analyzer, Reichert) were evaluated during a 12-month follow-up. Vector analysis of astigmatic changes was performed. Results: A statistically significant reduction of sphere (p = 0.043) was observed at 1 month after surgery, with a significant improvement of uncorrected distance visual acuity associated (p = 0.019). Likewise, a significant reduction of anterior corneal power measurements (p ⩽ 0.014) and steepest posterior keratometric reading (p = 0.006) were observed at 1 month postoperatively, with no significant changes afterwards (p ⩾ 0.133). No significant changes were observed in manifest cylinder (p ⩾ 0.175), corrected distance visual acuity (p ⩾ 0.174), flattest posterior keratometric measurement (p ⩾ 0.282), volumetric measurements (p ⩾ 0.051), and corneal biomechanical parameters (p ⩾ 0.068). Vector analysis revealed an initial trend to overcorrection of astigmatism, with a trend to undercorrection at the end of follow-up and a significant variability in the outcome achieved in each patient. Conclusion: The implantation of KeraRing segments in post-LASIK corneal ectasia generates a significant modification of spherical refraction and a visual improvement due to a central corneal flattening generated. More refined nomograms of implantation in these cases should be developed to achieve a more predictable correction of astigmatism.

Background Intracorneal ring segment implantation is an effective and safe method of visual improvement in patients with keratoconus. The aim of our study was to evaluate the long-term clinical outcomes after Keraring implantation for keratoconus in patients older than 40 years. Methods Eleven eyes from 11 patients with keratoconus who underwent femtosecond laser-assisted Keraring implantation for keratoconus were included in this retrospective study. The uncorrected visual acuity (UCVA), corrected visual acuity, keratometric readings, central corneal thickness and thinnest corneal pachymetry were evaluated preoperatively and 6 months after the Keraring implantation. Results UCVA, BCVA and keratometric readings improved at 6 months postoperatively. Conclusion Our data showed significant keratometric amelioration and visual improvement after Keraring implantation for keratoconus in patients older than 40 years at 6 months postoperatively.

Purpose: To assess the changes in visual acuity and topographic indices after implantation of single-segment Intacs. Methods: Forty-two keratoconic eyes received Femtosecond-assisted single-segment Intacs. Uncorrected distance visual acuity (UDVA) and best spectacle corrected visual acuity (BSCVA), refractive error, keratometry (K1, K2, Km, and KMax.), and seven Pentacam measured topographical indices; index of surface variance (ISV), index of vertical asymmetry (IVA), keratoconus index (KI), central keratoconus index (CKI), index of height asymmetry (IHA), index of height decentration (IHD), and minimum radius of curvature (R Min) were assessed 4 months after surgery. Correlations between changes of visual acuity and topographical indices changes were evaluated. Results: UDVA increased from 0.92 ± 0.35 to 0.49 ± 0.31 logMAR (P

Introduction The purpose of this study was to report the first case of acute bacterial keratitis produced by methicillin-resistant Staphylococcus aureus after the implantation of two intracorneal ring segments during an uneventful procedure for treating keratoconus in a 13-year-old child. Case Report A patient with grade III keratoconus underwent an implantation of intracorneal ring segments with no complications during the procedure. Three days later, a whitish corneal infiltrate appeared in between the union of both corneal rings. Sample cultures were positive for methicillin-resistant S. aureus (MRSA). Corneal infiltrate did not improve despite intensive topical and systemic antibiotics. Melting appeared even after the explantation of both corneal rings. Keratoplasty à chaud had to be performed to preserve the eye integrity. Conclusions MRSA keratitis following intracorneal ring segment implantation is a rare but severe complication that can lead to a therapeutic penetrating keratoplasty to definitely cure the process.

To compare the actual depth of the tunnel created with femtosecond laser for intracorneal ring segment (ICRS) implantation with the target depth in keratoconus patients. In this mix design study, eligible keratoconus patients were identified through chart review. The inclusion criterion was a history of ICRS implantation with femtosecond laser more than 6 months prior to enrollment. Participants underwent anterior segment optical coherence tomography using Spectralis (Heidelberg Engineering GmbH, Heidelberg, Germany) for depth measurement defined as the distance from the anterior corneal surface to anterior rim of the ring. The mean age of the 30 participants was 31.4 ± 7.9 years, and 58.6% were male. Mean follow-up time after ring implantation was 25.8 ± 10.0 (range 7–41) months. Mean actual depth was 59.9% (42.4–86.8%), and the target depth was 85.0% (74.8–90.0%) (P

Purpose To evaluate the safety and visual outcome of intracorneal ring segment (ICRS) implantation followed by cross-linking in pediatric keratoconus patients. Design Retrospective interventional case series. Methods This retrospective study included pediatric patients (aged ≤14 years) with keratoconus and poor corrected distance visual acuity (CDVA) that underwent ICRS implantation and cross-linking (CXL). ICRS were inserted under topical anesthesia after creating a corneal tunnel with a femtosecond laser. Cross-linking was performed 1 month subsequently. Records were reviewed and data collected preoperatively and at 6 months, 1 year, 2 years, and 4 years postoperatively. Results Twelve patients (17 eyes; 10 male, 2 female) aged 9–14 years (mean age 12.3 years) received ICRS implantation followed by CXL. Follow-up times ranged from 6 months to 4 years after surgery. At the 6-month follow-up all eyes were evaluated; at the 1-year, 2-year, and 4-year follow-up 11, 10, and 7 eyes were evaluated, respectively. At the 6-month follow-up, mean CDVA in comparison to preoperative levels improved significantly ( P = .001) from 0.30 ± 0.19 logMAR to 0.12 ± 0.1 logMAR; mean uncorrected distance visual acuity (UDVA) also improved significantly from 0.90 ± 0.50 logMAR to 0.43 ± 0.31 logMAR. A significant decrease in both keratometry readings and spherical equivalent (from −4.0 to −1.56 diopters) was also noted after ICRS insertion. At the 1-year, 2-year, and 4-year follow-up refractive values remained relatively stable in comparison to the 6-month follow-up, except for a minor but significant improvement in cylinder and, at 4 years, in UDVA. All patients tolerated the surgery well and no intraoperative or postoperative complications were reported, except for 1 ring segment that had to be removed after 2 years owing to vascularization and corneal thinning. Conclusion ICRS implantation is a safe and effective procedure for visual rehabilitation in children with keratoconus and poor CDVA.

PURPOSE To evaluate the efficacy, predictability, and safety of combined corneal collagen cross-linking (CXL), intracorneal ring segment (ICRS) implantation, and superficial phototherapeutic keratectomy (PTK) in patients with keratoconus. METHODS Fifty-five eyes received ICRS implantation, followed by CXL and PTK combination treatment. Patients were followed up for 6 months. Primary outcomes included Logarithm of the Minimum Angle of Resolution (LogMAR) uncorrected distance VA (UDVA) and corrected distance VA (CDVA), sphere, cylinder, mean spherical equivalent, index of surface variance, index of vertical asymmetry, keratoconus index, central keratoconus index, index of height asymmetry, and index of height decentration. Secondary outcomes were higher-order aberrations (HOAs), including HOA total, coma, spherical, secondary astigmatism, and trefoil. RESULTS At 6 months, there was a statistically significant improvement in UDVA, CDVA, sphere, and cylinder compared with baseline (P < 0.001). UDVA improved in 14% of the eyes to 20/25 and 96% had at least 20/40 or better spectacle corrected vision; 30.9% of the eyes were within ±0.5 diopter (D), 45.5% of the eyes were within ±1.0 D, and 74.5% of the eyes were within ±2.0 D. For CDVA, 1 eye (2%) lost 3 lines (but gained UDVA), 11% lost 1 line, 38% showed no change, and 49% gained between 1 and 8 lines of vision. Eighty-eight United Arab Emiratespercent of the eyes had at least 1 line of UDVA visual improvement, 79% improved by ≥2 lines, and 69% improved by ≥3 lines. HOA total, coma, spherical aberration, and secondary astigmatism showed improvements of -0.87 (P < 0.001), -0.84 (P < 0.001), -0.10 (P = 0.002), and -0.15 (P = 0.035), respectively. CONCLUSIONS A combined procedure of ICRS implantation, CXL, and PTK is effective, predictable, and apparently safe for patients diagnosed with moderate keratoconus.

Purpose. To report one-year outcomes of a modified version of two-stage multimodal surgical protocol for moderate keratoconus which has been suggesting promising preliminary results. Materials and Methods. 30 eyes of 25 patients with moderate keratoconus who exhibited visual complaints and/or disease progression were included for this retrospective case study. Approximately 3 months after implantation of intracorneal ring segment (Intacs SK™), a combination of corneal wavefront-guided transepithelial photorefractive keratectomy (CWG-transPRK, Schwind Amaris® 1050, and Schwind Sirius) and accelerated collagen cross-linking (accCXL, Avedro KXL™) was performed. Patients were examined for uncorrected and corrected distance visual acuity (UDVA; CDVA), keratometric power (K), corneal thickness, and corneal higher-order aberrations (HOAs) preoperatively and at postoperative 1, 3, 6, and 12 months. Results. The median UDVA and mean CDVA were enhanced from 6/38 to 6/12 and from 6/19 to 6/7.5, respectively, through 12 months after CWG-transPRK/accCXL. The 12-month CDVA of all patients was better than 6/12 Snellen, and no subject lost one or more lines of CDVA. The magnitudes of both myopia and corneal steepness were decreased in turn by Intacs SK implantation and also by CWG-transPRK/accCXL, but the reduction in HOA was largely the result of CWG-transPRK/accCXL. The magnitude of corneal thinning stabilized within 3 months after CWG-transPRK/accCXL. Conclusion. This approach may allow patients with moderate keratoconus to obtain satisfactory vision without the need for contact lens wear. This surgery appeared to be effective and safe through 1 year of follow-up.

Intracorneal ring segment (ICRS) implantation represents a modern, minimally invasive, surgical option for visual improvement in patients with keratoconus. ICRS modify the corneal geometry in a manner that enhances its refractive properties and thereby, they improve visual acuity. It is well-documented that implantation of ICRS decreases the keratometric readings, spherical equivalent and cylinder, reduces high-order aberrations and improves uncorrected distance visual acuity (UDVA) and best-corrected distance visual acuity (BCDVA) in patients with keratoconus. Success rate after ICRS implantation is high, depending on appropriate patient selection and adherence to suitable implantation nomograms, and most important, the overall complication rate is very low. This review is summarizing current indications/contra-indications for ICRS implantation, implantation techniques, clinical outcomes and potential complications, shedding light on myths and realities related to this innovative surgical option.

Purpose: To report visual outcomes and corneal biomechanical changes after femtosecond-assisted Intacs SK implantation in keratoconic eyes. Methods: This prospective interventional case series is comprised of 32 keratoconic eyes of 25 patients with mean age of 23.8 ± 5.4 years. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, refraction, manifest refraction spherical equivalent (MRSE), keratometry, central corneal thickness (CCT), corneal hysteresis (CH) and corneal resistance factor (CRF) were measured preoperatively, and 1, 3 and 6 months postoperatively. Results: Mean UDVA improved from 0.81 ± 0.3 LogMAR preoperatively to 0.53 ± 0.2 LogMAR six months postoperatively (P < 0.001). At 6 months, MRSE was significantly reduced only in eyes with moderate KCN (mean change, +2.61 ± 0.54 diopter [D]; P< 0.001). A significant improvement in sphere (mean change, +1.92 ± 0.37 D; P< 0.001) and mean keratometry (mean change, -3.34 ± 0.47D; P< 0.001) were observed. CCT increased from 446.1 ± 38 μm preoperatively to 462.2 ± 50 μm at six months (P < .001). CRF decreased from 6.5 ± 1.6 mmHg to 5.9 ± 1.1 mmHg six months after surgery (P = 0.02). CDVA, refractive cylinder and CH did not change significantly (P = 0.48, 0.203 and 0.55, respectively). Linear regression analysis disclosed that a decrease in CCT and moderate KCN are associated with higher CRF (standardized B,-0.513 and 0.314;P= 0.004 and 0.024, respectively; Adjusted R square = 0.353). Conclusion: Visual, refractive and keratometric indices remarkably improved in a parallel fashion. CRF was inversely associated with CCT. Changes in CRF represent the trend of changes in corneal biomechanics and thickness during the early postoperative months.

Purpose The aim of this study was to evaluate the effect of femtosecond laser-assisted intrastromal corneal ring segment (ICRS) implantation in patients with keratoconus on the visual outcome and corneal biomechanics using CORVIS ST. Patients and methods This is a prospective interventional study that was carried out on 30 keratoconic eyes which underwent femtosecond laser-assisted ICRS implantation. All the included eyes were assessed before ICRS implantation for uncorrected/best-corrected visual acuity, Pentacam and Corvis ST imaging. They were assessed again at 1 and 3 months after the implantation for the same parameters. Results The mean age of the studied group was 24.00±3.80 years. The uncorrected corrected visual acuity improved significantly at the first (0.36±0.04, P

Penetrating and – to some extent, Deep anterior lamellar keratoplasty (PK and DALK, respectively) – represent the ‘old’ generation of treatments for keratoconus (KC). Increasingly, they are being replaced by newer, less invasive techniques, like ultra-violet corneal crosslinking (UV-CXL) and intracorneal ring segment (ICRS) implantation. Even more recently, Bowman layer (BL) transplantation has been introduced for patients with advanced KC; the operation is designed to stiffen, strengthen, and flatten the recipient cornea into a more normal, stable configuration and thereby prevent or delay the need for more invasive treatment. Here, we provide an overview and history of this new technique, and relay the operation’s mid-term surgical results.

To analyze the visual and refractive outcomes of combined accelerated cross-linking with femtosecond laser intracorneal ring segment implantation for the treatment of pediatric keratoconus.This retrospective multicenter noncomparative clinical study included 63 eyes of 37 patients (age, 9-17 years) who underwent between August and September 2016 combined cross-linking with intracorneal ring segment implantation for keratoconus. Preoperative and postoperative (6, 12, and 18 months) uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), subjective refractions, keratometry (K), and pachymetry measurements were compared.The postoperative spherical equivalent refraction was within ±1 D, ±2 D, and ±3 D in 19 (30.2%), 27 (42.9%), and 37 (58.8%) eyes, respectively. Only 27 eyes achieved the attempted preoperative spherical equivalent refraction. The mean spherical equivalent refraction significantly improved from -6.01 ± 2.97 to -3.13 ± 2.78 D postoperatively (P 0.0001). The mean K average reading significantly decreased from 48.75 ± 4.25 to 46.65 ± 3.89 D postoperatively (P 0.0001). The mean postoperative myopic, astigmatic, and spherical equivalent corrections were -2.17 ± 2.19, -1.52 ± 2.03, and -2.93 ± 2.35 D, respectively. The mean UDVA and CDVA showed significant improvements (0.89 ± 0.33 to 0.40 ± 0.28, P 0.0001; 0.35 ± 0.31 to 0.25 ± 0.24, P = 0.004; respectively) at 18 months postoperatively. Keratoconus progression, segment migration, and segment extrusion were seen in four (6.4%), one (1.6%), and three (4.7%) eyes, respectively, probably contributing to the lower mean postoperative CDVA.Cross-linking plus is only partially effective for pediatric keratoconus. Despite some improvements in vision and keratometry measures, it resulted in complications such as keratoconus progression, segment extrusion, and segment migration that affected the vision in some patients. These findings suggest an assessment of standard epithelium-off collagen cross-linking as a sole procedure to treat pediatric keratoconus in future studies.

To compare surgical sequences of combined intracorneal ring segment (ICRS) implantation and corneal collagen cross-linking (CXL) in keratoconus and corneal ectasia in terms of visual, refractive, and keratometric outcomes.A comprehensive electronic search (in PubMed, Web of Science, Scopus, Embase, and Cochrane Library) was conducted in accordance with the PRISMA statement to find articles on combined ICRS implantation and CXL in keratoconus and corneal ectasia. The search period was from the inception of the database up to April 2017. Eligible articles were categorized into 3 surgical sequences (same day, ICRS first, and CXL first) and assessed qualitatively. Articles with 12 months of follow-up data after combined surgery were included in the meta-analysis.The initial search identified 120 related articles, of which 17 were included in the review after screening. The quality assessment showed that visual, refractive, and keratometric improvement was observed in all studies in all 3 groups of combined surgery. Meta-analysis on 6 studies that reported 12-month follow-up outcomes showed no significant differences between the 3 groups regarding uncorrected and best-corrected visual acuity and cylindrical refractive error. However, results with simultaneous surgery were superior to the CXL-first technique in terms of spherical refractive errors and flat-K (P = 0.011 and P = 0.0001, respectively) and to both CXL first and ICRS first in terms of steep-K (P = 0.002 and P = 0.007, respectively).Simultaneous ICRS implantation and CXL may provide better outcomes than staged techniques for improving the corneal shape.

To assess the corneal topometric parameters that can be predictive for better visual gain after intracorneal ring segment (ICRS) implantation in eyes with keratoconus.A total of 42 eyes of 32 patients who underwent ICRS implantation at Dokuz Eylul University, Deparment of Ophthalmology, Cornea Divison were included. Changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive errors, and corneal topometric indices measured using Scheimpflug topography (Pentacam, Oculus) were evaluated retrospectively.After creation of intrastromal tunnels of 5.01±0.03 mm inner diameter, 5.71±0.03 mm outer diameter and at 384.21±34.12 μm depth, 1 or 2 ICRS of 150 to 350 µm thickness and 90 to 210° arc length were implanted. Preoperative UDVA of 0.09±0.10 and CDVA of 0.29±0.14 Snellen lines improved postoperatively to 0.42±0.26 and 0.62±0.24, respectively (P0.001 for both). Preoperative spherical equivalent of -6.35±4.58D and refractive astigmatism of -5.89±2.40D decreased to -3.59±3.86 and -2.25±1.66D, retrospectively (P0.001 for both). Strong negative correlations were detected between preoperative mean simulated keratometry (SimKavg)/index of surface variance (ISV) and changes in UDVA/CDVA (P0.01, for all). Postoperative change in ISV was positively correlated with thicknesses of implanted rings. Change in topographical keratoconus classification was positively and change in index of vertical asymmetry was negatively correlated with number of implanted rings (P0.05 for all).Preoperative ISV value seems to be beneficial in predicting visual gain after ICRS implantation, in addition to SimKavg. Future work on new nomograms for ICRS selection that include ISV, besides refractive, topographic, and cone location data, is warranted.

Amr Mounir, Gamal Radwan, Mahmoud Mohamed Farouk, Engy Mohamed Mostafa Department of Ophthalmology, Faculty of Medicine, Sohag University, Sohag, Egypt Objectives: To document the difference between complication rate in the early curve of practicing intracorneal stromal rings and after gaining experience. Patients and methods: A retrospective study of 623 eyes of 417 patients with keratoconus who underwent Keraring implantation using femtosecond laser for channel creation. Results: The main outcome measures were reported intraoperative and postoperative complications. The overall complication rate was 12.7% (79 eyes) over the 4 years with 34 eyes in the first year (5.5%) and six eyes in the fourth year (0.96%). Over the 4 years of our practice, intraoperative complications were 7.1% and postoperative complications were 5.6%. Yet, there was a significant difference in intraoperative complications between the first and the fourth year where it was 3.5% and 0.48%, respectively. This also applies to the postoperative complication rate, which decreased from 1.9% to 0.5% in the fourth year. Conclusion: Complications with femtosecond-assisted intracorneal stromal ring procedure can be reduced by experience, making this procedure a safe and effective means of treating keratoconus. Yet, there are some complications that cannot be avoided such as sterile keratitis. Keywords: femtosecond laser, intracorneal rings, Kerarings, keratoconus

To assess the changes in the ABCD keratoconus staging system 6 months after intracorneal ring segment implantation.Fifty eyes of 50 patients with keratoconus who were implanted with the Keraring (Mediphacos, Belo Horizonte, Brazil) using the femtosecond laser were assessed. Preoperative and postoperative assessments included determination of distance uncorrected visual acuity and distance corrected visual acuity (DCVA), refraction, and Scheimpflug tomography with the Pentacam HR. In the ABCD keratoconus staging system, the elements A, B, C, and D stand for anterior and posterior radii of curvature in a 3.0-mm zone centered on the thinnest point (TP), corneal thickness at the TP, and DCVA, respectively.Keraring implantation produced significant flattening changes (preoperatively vs. postoperatively) in the anterior (6.60 ± 0.48 vs. 7.22 ± 0.57 mm, P0.001) and posterior (4.99 ± 0.47 vs. 5.16 ± 0.53 mm, P = 0.002) radii of curvature of the 3-mm zone centered on the corneal TP associated with a statistically significant improvement in the DCVA (0.56 ± 0.24 vs. 0.70 ± 0.22 in the decimal notation, P = 0.001) with no significant change in the corneal thickness at the TP (P = 0.285). The most changes occurred in element A of the ABCD keratoconus classification. Also, a 1-stage change was observed for element B, whereas elements C and D did not show changes in their postoperative stages after ring implantation. ABCD keratoconus staging before ring implantation was A2B3C2D1 and changed to A1B2C2D1 6 months after surgery.The ABCD staging system provides a more comprehensive guide that better illustrates the structural changes and visual acuity as one aspect of visual function after the implantation of the intrastromal corneal ring segments.

Intracorneal ring segment (ICRS) implantation is a safe and effective surgical technique with a low rate of complications. The use of femtosecond laser for the creation of the stromal tunnel increases the safety of ICRS implantation. A high risk of losing lines of vision after ICRS implantation is observed in those patients with good visual function prior to the procedure. It is advisable to demonstrate the stability of keratoconus previous to ICRS implantation as halting progression of the disease has not been demonstrated with this surgical technique.

To assess the clinical outcomes after sequential surgical implantation of intracorneal ring segments and transepithelial corneal collagen cross-linking (TE-CXL) in keratoconic eyes.In this consecutive randomized study, 40 eyes of 29 patients with progressive mild to moderate keratoconus were included and were randomly divided into two groups. Group 1 included 20 eyes that underwent Keraring implantation, and group 2 included 20 eyes that underwent Keraring insertion followed by TE-CXL 1 month later. In both groups, channel creation was performed manually. Visual, refractive, and topographic outcomes were measured preoperatively and 1, 3, and 6 months postoperatively.There was statistically significant improvement in both groups regarding uncorrected distance visual acuity (P0.001) and corrected distance visual acuity (P0.001), with a significant reduction in the refractive error and keratometric values (P0.001). There was no statistically significant difference between both groups regarding changes in uncorrected distance visual acuity, corrected distance visual acuity, and refractive error (P0.05). However, group 2 revealed a more statistically significant reduction in spherical refraction after 3 months (P = 0.04) and highly significant improvement after 6 months (P = 0.004).Intracorneal ring segment implantation is an effective procedure for visual and refractive improvement in keratoconic eyes. The addition of TE-CXL to the procedure compensates for residual superficial irregularities, disrupts the progression of the disease, and provides greater improvements in spherical values. The process is simply a deep stretch with superficial lamellar stiffness.

Purpose: To present a case of a complicated intracorneal ring segment (ICRS) implantation procedure in a patient with keratoconus, who experienced significant visual improvement, although the ICRS implantation had to be aborted. Methods: A 25-year-old female patient with keratoconus underwent femtosecond laser-assisted ICRS implantation in her right eye (OD) for improving visual acuity. Results: The procedure had to be aborted, because ICRS implantation was not possible. Anterior segment imaging 1 month after the procedure showed full-thickness corneal incision with corneal microperforation. However, patient’s visual acuity improved significantly due to amelioration of the keratometric findings. Keratometric and visual improvement was preserved at 6 months postoperatively. Conclusion: Our case report shows that femtosecond laser-assisted full-thickness corneal incision on the astigmatic axis combined with the intracorneal tunnel creation resulted unexpectedly in keratometric and visual improvement in this keratoconus patient, even without the implantation of the ICRS.

Keratoconus is a corneal degeneration that usually appears during puberty and may seriously deteriorate the quality of life of the patients. This corneal disease is today the first indication of corneal transplantation in young patients. Until the last decade of the XX century, keratoplasty procedures were the only alternative to treat this pathological condition. In the beginning of the XXI century, intracorneal ring segments implantation was proposed as a therapeutic choice for treating keratoconus patients. Since then, several published articles have reported the benefits of this surgical procedure in treating this type of corneal ectatic disorder. The purpose of the present investigative work is to summarize the characteristic of the intracorneal ring segments and also to review the different features published in the literature in relation to this surgical technique for the treatment of keratoconus patients.

BACKGROUND AND OBJECTIVE: To examine the exact position of implanted Keraring (Mediphacos, Belo Horizonte, Brazil) segments by high-resolution anterior segment optical coherence tomography (AS-OCT). PATIENTS AND METHODS: This study included 17 eyes of 13 patients with keratoconus who underwent uneventful intracorneal ring segment implantation with the aid of femtosecond laser. Eyes were evaluated by AS-OCT at the third postoperative month. Distance from the apex of the triangular cross-section of the ring segment to the anterior corneal surface and distances from two basal corners to the posterior corneal surface were measured. RESULTS: Distance from apex to anterior corneal surface (263.1 ± 42.9 μm) was significantly smaller than target depth calculated intraoperatively (356.9 ± 35.7 μm, P < .001). Distance between outer basal corner and posterior corneal surface was significantly greater than distance between inner basal corner and posterior corneal surface. CONCLUSION: High-resolution AS-OCT is a rapid, convenient, and valuable technique in the follow-up of patients with implanted Keraring segments that may be helpful in predicting ring-related complications.

PURPOSE To compare changes that occur at the posterior corneal surface after the implantation of intracorneal ring segments (ICRSs) using either mechanical or femtosecond laser-assisted procedures and to correlate these changes with the visual outcome achieved. METHODS Retrospective, nonrandomized, and interventional case series including 223 consecutive eyes of 186 patients with keratoconus ranging in age from 16 to 39 years that were implanted with ring segments (KeraRing; Mediphacos) at Kartal Training and Research Hospital, Istanbul, Turkey. Two groups were created according to the surgical technique used: mechanical group (168 eyes) and femtosecond group (55 eyes). Visual and refractive outcomes and corneal elevation changes were evaluated during a 24-month follow-up. Correlations between visual and posterior elevation changes were evaluated. RESULTS The posterior corneal surface could not be analyzed with accuracy for diameters larger than the diameter of the ICRS implant. A statistically significant reduction of maximum elevation for both the corneal surfaces was observed at 1 month after the surgery (P < 0.01), with additional reductions at 3 and 6 months (P ≤ 0.03). In addition, the posterior best-fit sphere was flattened significantly at 1 month after the surgery in both the groups, with additional flattening at 3 months (P ≤ 0.03). No significant differences between groups in posterior corneal elevation parameters were found at any time point of the follow-up (P ≥ 0.14). Moderate and significant correlations of the postoperative visual outcome with the change in posterior best-fit sphere were found only in the femtosecond group. CONCLUSIONS A central corneal flattening of the posterior corneal surface occurs after ring segment implantation in keratoconus.

To assess the outcome of collagen crosslinking (CXL) in keratoconus eyes after implantation of Kera intracorneal ring segments.Twenty-one eyes of 13 patients with mild to moderate degree of keratoconus were included in this study. All eyes had uneventful surgery for Kera intracorneal ring segment implantation followed by collagen CXL treatment after at least 3 months of the implantation. Inclusion criteria were absence of corneal scarring and corneal thickness higher than 400 mm. Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent and cylinder refraction, and the mean keratometric (K) values were evaluated preoperatively and postoperatively.The mean age was 21.36 ± 4.46 years (range 16-28). Mean time between implantation of Kera ring and CXL was 4.56 ± 3.2 months. The mean baseline UCVA and BCVA were 0.05 ± 0.02 and 0.18 ± 0.1, respectively; after Kera ring, the mean UCVA and BCVA were 0.23 ± 0.17 and 0.39 ± 0.18 (p=0.000), respectively. Collagen CXL after Kera ring resulted in an additional change in UCVA and BCVA to become 0.23 ± 0.17 (p=0.951) and 0.41 ± 0.18 (p=0.08), respectively. Also, CXL results in an additional change in spherical equivalent, cylindrical, and mean keratometric values. The decrease in spherical equivalent, cylindrical, and mean keratometric value was 2.8 D (p0.05), 2.1 D (p0.05), and 2.5 D (p0.05), respectively, after Kera ring treatment. An additional decrease of 0.11 D (p0.05), 0.01 D (p0.05), and 0.09 D (p0.05) was obtained after CXL in each respective parameter.Collagen CXL has an additive effect after Kera ring implantation and may be considered as an enhancement/stabilizing procedure.

Juliane de Freitas Santos Paranhos, Marcos Pereira Ávila, Augusto Paranhos Jr, Paulo SchorFederal University of São Paulo, São Paulo, BrazilPurpose: To prospectively evaluate intracorneal ring segment (ICRS) implantation on quality of life (QoL) of patients with keratoconus changes and identify factors responsible.Methods: Sixty-nine eyes of 42 keratoconus patients were implanted with the Keraring (Mediphacos, Belo Horizonte, Brazil). Best corrected visual acuity (BCVA), refraction, and steep keratometry were analyzed 3 months and 1 year after surgery. All patients self-administered the National Eye Institute Refractive Error Quality of life instrument at 2 time points: after having worn best correction for at least 30 days since evaluation (mean 4 months after surgery) and 1 year after surgery. To analyze if the use of the appropriate correction at 1 year follow up had any impact on visual acuity and V-QoL, patients were divided into 2 groups: group A (appropriate correction) and B (not appropriate correction).Results: After 1 year, QoL changes related to scales ‘clarity of vision’, ‘near vision’, and ‘far vision’. Keratometric values, sphere, and spherical equivalent did not differ significantly between 3 months and 1 year postoperative. Cylinder increase was statistically but not clinically significant. Binocular BCVA did not change 1 year after surgery in group A and showed a clinically significant impairment in group B. A year after surgery, 18 patients did not use correction suggested by a physician 3 months after surgery. QoL was not statistically different 1 year after surgery between group A and group B.Conclusion: Our findings show that the way keratoconic patients see is difficult to analyze using only quantitative and 1-visit metrics. They highlight the importance of patients’ self perception and performing longitudinal analysis to consider neural compensation to optical changes from surgery.Keywords: keratoconus, cornea, quality of life&nbsp

Keratoconus is a noninflammatory, usually bilateral, progressive disease. It is a pathology characterized by a progressive thinning and ectasia of the stroma that results in a cone-shaped cornea. In advanced keratoconus with corneal opacities, keratoplasty was regarded as the only surgical alternative. Recently, new treatment alternatives were developed in keratoconus treatment, such as intracorneal ring segments and corneal crosslinking. Intracorneal ring segments act as spacer elements between the bundles of corneal lamellae, producing a shortening of the central arc length. Corneal crosslinking treatment increases the stiffness of the cornea. Several studies reported that collagen crosslinking can delay or stop keratoconus progression and produce a better quality of vision. A combination of crosslinking and intracorneal ring segments shows a positive, synergistic effect. Keratoconus is a disease of the corneal stroma and that usually presents itself in patients at an early age, thus the endothelial cel...

Keratoconus is a corneal ectatic disease that is characterized by noninflammatory progressive thinning. Since the utilization of penetrating keratoplasty and rigid contact lenses, there was no improvement for the visual rehabilitation of the keratoconus. Recently, intracorneal ring segments have been investigated to correct ectatic corneal diseases. The aim of implanting intracorneal ring segments is not to treat or eliminate the existing disease, rather a surgical alternative to decrease the astigmatism and corneal abnormality and thus increase the visual acuity to acceptable limits, aiming to at least delay, if not eliminate, the need of corneal grafting. Since its release, intracorneal ring segment implantation for keratoconus seems to be an effective and, most of all, reversible treatment with minimal complications. Conversely, long-term results should be analyzed regarding stability, predictability and the need for further corneal transplantation in the long term.

To assess the safety and efficacy of intracorneal ring segment (Intacs, Addition Technology, Inc.) implantation in the management of keratoconus.Department of Ophthalmology and Ophthalmic Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.This prospective case series comprised 30 keratoconic eyes (22 patients) with a clear central cornea that had Intacs implantation. All patients were contact-lens intolerant. The main outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, keratometry, and pachymetry. Patients were examined before Intacs implantation as well as 1 week and 1, 3, and 6 months postoperatively.The mean age of the 5 women and 17 men was 25.9 years +/- 5.29 (SD). The mean UCVA improved from 0.60 +/- 0.311 logMAR preoperatively to 0.29 +/- 0.20 logMAR 6 months postoperatively (P.001) and the mean BSCVA, from 0.25 +/- 0.16 logMAR to 0.13 +/- 0.14 logMAR, respectively (P.001). The mean spherical equivalent improved from -6.93 +/- 3.52 diopters (D) preoperatively to -3.23 +/- 2.81 D at 6 months and the mean refractive cylinder, from -4.65 +/- 1.85 D to -3.90 +/- 1.70 D, respectively. The mean keratometry decreased from 49.84 +/- 3.58 D preoperatively to 47.90 +/- 3.58 D postoperatively (P.001). Three eyes had ring exposure, and 1 eye had bacterial keratitis and ring exposure.Intacs implantation appeared to be effective in improving UCVA and BSCVA in patients with mild to moderate keratoconus and contact-lens intolerance.