Corneal Ring Segment Implantation Research Articles

Outcomes of 320-degree intrastromal corneal ring segment implantation for advanced keratoconus.

The purpose of this study is to investigate visual and tomographic outcomes and complications of long-arc length intrastromal corneal ring segment (ICRS) implantation for the treatment of advanced keratoconus. This retrospective study enrolled 10 eyes of 9 subjects. All patients received 320-degree ICRS (320-ICRS) implantation with femtosecond laser-assisted technique based on their advanced grading with preoperative high keratometry (K) value, asphericity (Q), and astigmatism. Medical records and corneal tomography changes of consecutive patients were reviewed at baseline, 1, and 3 months after treatment. There are 6 female and 3 male patients with a mean age of 29.6 ± 7.8 years in this study. Mean K (Km) reduced from 59.01 ± 5.81 D preoperatively to 50.7 ± 5.3 and 50.2 ± 3.66 postoperatively (after 1 month and 3 months respectively, P < 0.001). The changes in mean K, K1, K2, and maximum K (Kmax) reading were all statistically significant (all P < 0.001). Mean uncorrected distance visual acuity (UCVA) improved from 20/400 to 20/200. Mean best-corrected distance visual acuity (BCVA) improved from 20/100 to 20/60. Both UCVA and BCVA showed a trend of improvement at postoperative month 3, though insignificant in BCVA (P = 0.114). Mean Q improved from -1.59 ± 0.62 preoperatively to -0.48 ± 1.08 and -0.11 ± 1.04 postoperatively (after 1 month and 3 months respectively, P = 0.016, 0.002). No intraoperative or postoperative complications were observed. The present results suggest that implanting a 320-ICRS is a safe and effective procedure for treating patients with advanced keratoconus. Preoperative corneal measurements and the selection of types and thickness of ICRS are important to prevent unpredictable results.

Corneal densitometry changes in keratoconus patients after intrastromal corneal ring segments implantation

Background Keratoconus (KC) is an ectatic corneal disorder characterized by progressive corneal thinning with myopic astigmatism. Intrastromal corneal ring segments (ICRS) have been broadly selected as a surgical intervention for KC correction to delay the need of keratoplasty. The purpose of this study was to evaluate the corneal densitometry changes in the various annuluses and depths in KC corneas after intrastromal corneal ring segment (ICRS) implantation and to correlate those changes with the other optical and refractive outcomes. Methodology This was a prospective interventional study included 56 eyes of 40 patients with KC who underwent femtosecond laser-assisted Keraring ICRS implantation. The uncorrected and best-corrected visual acuities (UCVA and BCVA), refraction, keratometry, Q-value, thinnest corneal location thickness (TCLT), and corneal densitometry in all the annular zones were assessed preoperatively and 90 days after surgery. Results Following the ICRS implantation after 3 months, when compared to preoperatively, the UCVA, BCVA, improved significantly from 0.21±0.12 and 0.44±0.15 to 0.27±0.12 and 0.58±0.15 (P&lt;0.001) and spherical equivalent (SE) decreased significantly, from −5.28±1.65 D to −4.05±1.24 D (P&lt;0.001) whereas the K1, K2, Km, Kmax, reduced significantly from 47.67±4.10 D, 51.39±4.74 D, 49.44±4.28 D, and 57.78±7.35 D, to 44.28±2.86 D, 46.84±3.42 D, 45.45±2.98 D, and 53.89±5.49 D (P&lt;0.001) respectively. Corneal astigmatism, and Q-value were markedly improved from 3.73±2.17 D and −0.99±0.5 to 2.55±2.08 and −0.28±0.5 (P&lt;0.001) .As regard corneal densitometry there was a significant elevation in the mean density of 2–6 mm annulus for the anterior and posterior layers (P=0.001), of 2–6 mm and 6–10 mm annuluses and total diameter for the central layer (P&lt;0.001, P=0.047, and P&lt;0.001, respectively), and of 2–6 mm annulus and total diameter for the total corneal thickness (P&lt;0.001 and P=0.014, respectively). In contrast, a significant decline in the densitometry readings was observed in the 10–12 annulus for the central, posterior, and total corneal layers (P=0.003, P&lt;0.001, and P=0.008, respectively). The percentage changes in the corneal densitometry readings did not significantly correlate with the percentage changes in the UCVA, BCVA, SE, CA and Q value. The percentage changes in the central and total 2–6 mm annuluses densities correlated negatively with the percentage changes in the K1 (r=−0.30, P=0.025 and r=−0.29, P=0.029, respectively), K2 (r=−0.33, P=0.013 and r=−0.31, P=0.021, respectively), and Km (r=−0.34, P=0.010 and r=−0.33, P=0.014, respectively). Conclusions The ICRS implantation results in significant changes in corneal densitometry specifically in the central corneal layer and in the 2–6 mm annulus, with an inverse correlation with keratometric values of the front corneal surface. Besides, ICRS leads to substantial improvements of refractive status, visual acuity and corneal keratometry and asphericity.

Clinical outcome of intrastromal corneal ring segment implantation with two different nomograms in keratoconus patients

Aim The aim of this study was to assess the clinical effects of Keraring implantation in patients with keratoconus (KC) using a newly created nomogram (NN) based on cone location and Q value compared with the manufacturer’s standard nomogram (SN). Patients and methods This is a prospective randomized controlled clinical trial that included 100 keratoconic eyes of 100 patients. The patients were randomly assigned into two groups: group NN and group SN. Group NN underwent Keraring implantation based on the newly developed nomogram, while group SN followed the manufacturer’s standard nomogram. The primary outcome measures included visual acuity, different refractive measurements, keratometry values, and Q values, while the secondary outcome measure was Belin ABCD KC grading. All outcome measures were evaluated at 12 months postoperatively. Results The mean age of group NN was 22.96±7.45 years and that of group SN was 24.12±7.00 years, with no statistically significant difference (P=0.46). At 3 months postoperatively, group NN demonstrated substantial improvements compared with group SN. Group NN exhibited a greater improvement in uncorrected distance visual acuity [mean difference (MD) in LogMAR visual acuity=−0.61 compared with −0.31 in group SN, P&lt;0.0001] and corrected distance visual acuity (MD: −0.34 LogMAR compared with −0.05 LogMAR in group SN, P&lt;0.0001). Significant reductions were noted in sphere (MD: 4.22 D in group NN compared with 2.33 D in group SN, P&lt;0.0001), refractive cylinder (MD: 2.87 D in group NN compared with 1.74 D in group SN, P=0.003), and spherical equivalent (MD: 5.56 D in group NN compared with 3.12 D in group SN, P&lt;0.0001). Keratometric values and Belin ABCD grading system (particularly A and D categories) also showed more pronounced improvements in group NN than in group SN (P&lt;0.0001). Conclusion The personalized approach of the new nomogram (NN) based on cone location and Q value resulted in superior visual, refractive, and corneal topographic outcomes compared with the standard nomogram (SN) during the implantation of Keraring in KC patients. The individualized nomogram allowed for more precise corneal reshaping and restoration of corneal asphericity.

Effect of intrastromal corneal ring segments on in vivo corneal biomechanics in keratoconus: 1-year results.

To evaluate the 1-year effects of the implantation of intrastromal corneal ring segments (ICRS) in keratoconus (KC) on the dynamic corneal response (DCR) parameters obtained with the Corvis. Fernández-Vega Ophthalmological Institute, Oviedo, Spain. Prospective, single-center, clinical study. Included were patients who underwent ICRS implantation for KC over a period of 1 year. On the day of the surgery and at least 6 months after ICRS implantation, the following measurements were made: corrected distance and uncorrected distance visual acuity, corneal tomography indices with the Pentacam, biomechanically corrected intraocular pressure and the Corvis DCRs (integrated inverse concave radius, deformation amplitude ratio, stiffness parameter at first applanation, stress-strain index [SSI] and the highest concavity radius). 30 eyes were included with a mean follow-up time of 15 months. Statistical analysis showed that ICRS implantation induced significant improvements in corneal biomechanics measurements between preoperative and long-term follow-up as demonstrated by a significant increase in SSI (P = .003). To confirm that this difference was actually induced due to a stiffening between early postoperative (previously published) and long-term an additional t-test was done between month 1 and late follow-up which confirmed a significant stiffening in the value of SSI (P = .01). Patients implanted with ICRS alone for KC showed a significantly stiffer response due to increased structural support compared with preoperative values and 1 month postoperative.

Интрастромальная фемтокератопластика с имплантацией роговичных сегментов в коррекции аберраций высшего порядка у пациентов с кератоконусом

Aim. To evaluate the potential of femtosecond laser assisted intrastromal keratoplasty (FLAIK) with implantation of corneal ring segments in the correction of higher order aberrations in patients with stage I–II keratoconus. Material and methods. 15 patients (14 men and 1 woman) were examined and treated surgically, in total of 17 eyes, with stage I and II keratoconus (according to the classification of Izmailova S.B., 2014). All patients underwent FLAIK with implantation of corneal ring segments. Results. The change in the estimated parameters at an average follow-up period of 4.7 months showed that after FLAIK with implantation of corneal ring segments, best corrected visual acuity increased statistically significantly (p &lt; 0.05) in all cases and increased by an average of 0.29 ± 0.09. In addition, there was a statistically significant (p &lt; 0.05) decrease in the total level of higher order aberrations by 1.5 times (by 0.69 ± 0.4 D), a decrease in the level of coma aberration by 1.7 times (by 0.74 ± 0.4 D), a decrease in the level of spherical aberration by 1.6 times (by 0.07 ± 0.12 D). Conclusions. FLAIK with implantation of corneal ring segments is an effective method for correcting higher-order aberrations in patients with keratoconus of stage I–II. FLAIK with keratoconus with implantation of corneal ring segments makes it possible to achieve a significant increase in BCVA in patients with stage I–II keratoconus. Key words: keratoconus, higher order aberrations, corneal segments, refractive surgery

Сравнительная оценка эффективности хирургического лечения кератоконуса комбинированным методом

Relevance. Keratoconus is a common asymmetric and usually bilateral ectatic corneal disease characterized by progressive corneal protrusion, resulting in reduced visual acuity and deterioration of optical properties. Purpose of the study. To evaluate the effectiveness of surgical treatment of keratoconus with various combined methods. Material and methods. The article presents a comparative analysis of data from patients with II and III stages of keratoconus (52 patients, 66 eyes) after implantation of intrastromal corneal ring segments with femtosecond accompaniment, followed by corneal crosslinking and corneal crosslinking, followed by implantation of intrastromal corneal ring segments with femtosecond accompaniment. Results and conclusion. The refractive result for the spherical and cylindrical components gave the best result in group 2, in which stage 1 was implantation of ICRS, and stage 2 was corneal collagen crosslinking, compared with group 1, in which stage 1 was corneal collagen crosslinking, and stage 2 was implanted ICRS. Progression stopped in 65 cases. Keywords: keratoconus, intrastromal corneal segments, femtosecond laser, corneal crosslinking.

Intrastromal corneal ring segment implantation in pediatric patients with keratoconus: long-term follow-up

Purpose: To evaluate the long-term outcomes of Intrastromal Corneal Ring Segments (ICRS) implantation in pediatric patients with keratoconus. Methods: Retrospective analysis of eyes with ICRS implantation in pediatric age. Uncorrected (UCVA) and best-corrected (BCVA) visual acuity, maximum and minimum keratometry (Kmax and Kmin), and corneal thickness at the thinnest point (CTTP) were evaluated preoperatively, 6 to 12 months after surgery, 5 years after surgery, and at the last follow-up visit (&gt;10 years after surgery). Results: Fourteen eyes (10 patients) were included. In 5 eyes all ICRS were explanted and in 1 eye, one of the segments was explanted. UCVA (p=0.028) and BCVA (p=0.028) improved 6 to 12 months after surgery and remained stable afterwards (p&gt;0.999). There was a decrease in Kmax and Kmin 6 to 12 months after surgery (p&lt;0.001 and p=0.012, respectively), with subsequent stability at the 5-year follow-up (p=0.736 and p=0.056, respectively). Kmax remained stable at the last follow-up (p&gt;0.999) but there was an increase in Kmin (p=0.028). There were no changes in CTTP (p=0.097). Conclusion: ICRS implantation seems to be a minimally invasive, and reversible procedure that leads to improvement of BCVA and keratometry readings. Despite this, the need for explantation increased overtime.

Detecting True Change in Keratoconus after Intracorneal Ring Segment Implantation.

Confirming the progression of keratoconus is of paramount relevance to providing the appropriate treatment. Real change should be considered consistent over time. It must be greater than the variability of the measurement of the device used to monitor the cornea. The present study aimed to assess the intraobserver repeatability and intersession reproducibility of a Scheimpflug camera in measuring corneal parameters in virgin keratoconus and intrastromal corneal ring segments (ICRS) implantation eyes to discriminate real change from measurement noise. Sixty keratoconus and 30 ICRS eyes were included. Corneal parameters were determined in three consecutive measurements and were repeated 2 weeks later. The precision within the same session for all parameters was better in the keratoconic eyes, with mean repeatability limits 33% narrower (range 13% to 55%) compared with ICRS eyes. Mean reproducibility limits were 16% narrower (range +48% to -45%) compared with ICRS eyes. The cutoff values to consider a real corneal shape change were lower for virgin keratoconic than for ICRS, except for the thinnest corneal thickness and Stage C (ABCD system), which were the opposite. Corneal tomography measurements in ICRS eyes showed worse accuracy than in virgin keratoconus, which should be taken into account by practitioners in patients' follow up.

Ferrara ring and the nomogram as the main strategy for correcting keratoconus: a systematic review of clinical findings

Introduction: In the setting of corneal ectasias, keratoconus (KC) is a bilateral and asymmetrical disease that results in progressive thinning and tilting of the cornea, leading to irregular astigmatism and decreased visual acuity. The condition affects all ethnicities and both sexes. KC prevalence and incidence rates are close to between 0.2 and 4790 per 100,000 people and 1.5 and 25 cases per 100,000 person-years, respectively. For surgeons who implant Ferrara rings, the manufacturer has developed an online nomogram aimed at optimizing patient outcomes. Objective: The present study carried out a systematic review to present the main clinical outcomes of keratoconus treatment using the Ferrara ring. Methods: The systematic review rules of the PRISMA Platform were followed. The literature search was carried out from January to February 2023 in Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. Scientific articles from the last 15 years were selected. The quality of the studies was based on the GRADE instrument. The risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 60 articles were found, of which only 21 were part of this systematic review, after an eligibility analysis.It was concluded that the insertion of Ferrara rings in keratoconic eyes with previous cross-linking history using the company's nomogram results in significant improvements in visual, refractive, and tomographic results. Corneal densitometry in the anterior layer of the cornea decreases after the implantation of intrastromal corneal ring segments and correlates with corneal keratometry. Over 5 years, Ferrara-type intrastromal corneal ring segment implantation is a safe, effective, and stable procedure for restoring vision in pediatric patients with keratoconus old.

Keratoconus: main lines of research

Keratoconus (KC) research focuses on studying pathogenesis, advancing diagnostic techniques and methods of correction and treatment. The working hypothesis for KC etiopathogenesis is based on abnormalities in distribution of microelements in the cornea and its potential influence on the processes of stromal collagen disorganization. Improvement of early diagnosis of KC is associated with evaluation of microstructural changes in the cornea using computerized methods such as Scheimpflug camera and high-definition optical methods for visualization of initial signs of a pigment ring. The main optimization directions of KC contact correction are associated with increasing gas permeability of the material, improving lens design and methods of lens fitting. Customized fitting of gas-permeable scleral hard contact lenses with consideration of topographic features of the anterior corneal surface allows achieving stable lens positioning and preserving the tear gap between the lens and the cornea. Alternative methods of correcting the refraction component of KC are associated with surgical interventions involving increase in corneal volume in the paracentral area. Implantation of corneal ring segments should be considered as an alternative to correction of refractive errors in cases with unsatisfactory individual subjective tolerance and insufficient patient compliance with contact correction. Femtolaser-assisted implantation of intrastromal allotransplants along with a decrease in the degree of spherical and astigmatic components of refractive errors contribute to prevention of KC progression. Advancement of techniques of corneal collagen cross-linking for prevention of KC progression is aimed at reducing the risk of developing post-operative complications directly related to the extent of intraoperative deepithelization. Limiting corneal ectatic area by implantation of intrastromal allotransplants can be considered an alternative approach. Deep anterior lamellar keratoplasty and penetrating keratoplasty are the surgeries of choice in replacing altered corneal layers in KC. With regard to the modern trends in selective keratoplasty, selective replacement of the cornea in lamellar keratoplasty reduces the rate of injuries and the risk of tissue reaction.

Pentacam findings after implantation of intrastromal corneal rings in keratoconus

Introduction Intrastromal corneal ring segment implantation is a minimally invasive procedure. Its main goals are to flatten and regularize the cornea, to improve uncorrected and corrected visual acuity, and to delay or even prevent a keratoplasty. ICRSs effect correlates directly to its thickness and inversely to its distance to the visual axis. Patients and methods A retrospective observational study involving 44 eyes of 44 patients was initiated. The files and pentacam printouts of 44 patients were retrospectively extracted and evaluated. The preoperative and postoperative ocular findings and pentacam parameters of anterior and posterior corneal surfaces, in addition to the pachymetry data, were recorded and analyzed. Results Forty-four patients with keratoconus were evaluated in this study. Evaluation of anterior corneal surface showed significant flattening of all keratometry readings (P &lt; 0.001) with significant improvement of corneal astigmatism (P = 0.03), corneal asphercity (P &lt; 0.001), the inferior-superior asymmetry (P = 0.019) and the front elevation (P = 0.005) The posterior corneal surface showed significant improvement in back elevation (P &lt; 0.001), and the back surface asphercity showed significant prolate shift (P = 0.01). The thinnest location was significantly upward displaced towards the corneal apex. kera 355° showed a significant flattening of all keratometry readings with significant improvement of corneal astigmatism and corneal asphercity of the anterior corneal surface and the back surface asphercity showed significant prolate shift (P = 0.001). The ICRS showed a significant flattening of km (P = 0.030) and corneal asphercity of the anterior corneal surface (P = 0.046). Conclusion The intracorneal ring implantation led to improvement of the tomographic corneal parameters which was more significant at the anterior corneal surface.

Allograft corneal ring segment for keratoconus management: Istanbul nomogram clinical results.

To evaluate the clinical feasibility and visual outcomes of allograft corneal ring segment implantation for the treatment of keratoconus. This case series, included forty-four eyes of 32 patients with a 6-month follow-up. All cases were treated according to the Istanbul nomogram. In the Istanbul Nomogram, corneal tunnels of 4 × 7.5 mm diameters are created at depth of 200 μm and implanted with sterile allograft corneal rings (KeraNaturalTM, Lions VisionGift, Portland, OR, USA) at the cone location. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent (SE) and keratometric values were compared preoperatively versus postoperatively. There was significant improvement in UDVA, CDVA, SE and topographic keratometric values. The mean preoperative CDVA (Snellen, decimal) increased from 0.29 ± 0.20, to 0.56 ± 0.26 (P < 0.001), at the last visit. There was no statistically significant difference between preoperative and postoperative thinnest pachymetry values (P = 0.509). No major complications or adverse event were observed during and after the operation. The results of this pilot study show that sterile allograft corneal ring segments may be safe, effective and enhance the visual performance of keratoconus patients. Larger clinical studies are needed to demonstrate the effectiveness and safety with long term follow-up.

Intrastromal corneal ring segments implantation with the aid of a femtosecond laser in cases of mild to moderate keratoconus: A 3‐year study

AbstractPurpose: To evaluate the 3‐year results of femtosecond assisted intrastromal corneal ring segments (ICRS) implantation for the treatment of mild to moderate keratoconus.Methods: Prospective case series including 4 eyes of 4 consecutive patients with keratoconus.Each patient was implanted with ICRSs according to the preoperative topography and refraction. The segments were implanted in intracorneal pocket created with the FS200 femtosecond laser. Planning of the operation was done based on the nomograms provided by the manufacturer. Patients' follow‐up involved visual acuity measurement, refraction control, clinical examination, corneal topography (Pentacam and Orbscan) and anterior segment OCT. The operation was performed due to patients' unsatisfying spectacle corrected visual acuity and contact lens intolerance.Results: Preoperative average steep keratometry was reduced from 53,3D (range 50.7–55.7D) to 48.6D (range 46.9‐50D) 3 years postoperatively. Preoperative average topographic astigmatism was 5.35D (range 4.2–7.9D) while postoperative was 2.7D (range 0.7–4.3D). Refraction assessment showed reduction of the refractive astigmatism from 3.5D (range 2.0–5.0D) to 2,5D (range 0.5–3.75D) and improvement of spherical equivalent from −5.0D (range − 4.0 to −7.25D) preoperatively to −2.5D (range −1.25 to −3.25D) 3 years postoperatively. Average pre‐op spectacle corrected visual acuity was 4/10, when post‐op visual acuity assessment on Snellen scale showed average improvement by 2 lines (range from 0 to 5 lines).Conclusions: The femtosecond assisted ICRS implantation based on the results of our study, improved all patients' visual acuity, topographic and refractive parameters 3 years postoperatively.

Sequential intracorneal ring segment implantation followed by transepithelial phototherapeutic keratectomy and corneal cross-linking

To evaluate the safety and visual outcomes of intrastromal corneal ring segment (ICRS) implantation followed by transepithelial phototherapeutic keratectomy (te-PTK) and corneal cross-linking (CXL) in patients with mild keratoconus. Patients with mildkeratoconusand contact lens intolerance who underwent sequential ICRS implantation followed by phototherapeutic keratectomy and corneal CXL between April 2015 and July 2018 were retrospectively included in the study. Refractive and visual outcomes, satisfaction questionnaire and complications were recorded at the last follow-up (mean 9.5 months postoperatively). Twenty eyes of 17 patients were enrolled, including 5 women and 15 men. The mean time between the two procedures was 16 months. Based on values before the first procedure and 9.5 months after the second procedure, significant improvements were noted in uncorrected distance visual acuity (UDVA) (0.80±0.35 logMAR vs. 0.46±0.38 logMAR), corrected distance visual acuity (CDVA) (0.38±0.23 logMAR vs. 0.13±0.16 logMAR), maximal K (56.11±4 diopters [D] vs. 50.6±3.56 D), mean K (51.87±3.43 D vs. 48.45±2.91 D), cylinder (7.99±3.94 D vs. 4.23±3.49 D), and spherical equivalent (-3.84±3.36 D vs. -0.99±2.15 D) (P<0.01). Among the outcomes, we noted 5 (25%) superficial corneal scarring (haze); 75% of eyes gained>=1 logMAR line of CDVA. In all, 94.5% of patients reported that they were satisfied with their outcomes. Combining ICRS implantation followed by te-PTK and corneal CXL appears to be a safe and effective approach for improving visual outcomes and quality of life in keratoconus patients.

Successful Management of Corneal Hydrops and Intrastromal Corneal Ring Segment (ICRS) Migration Following ICRS Implantation for Keratoconus

Patient: Male, 17-year-old Final Diagnosis: Acute corneal hydrops • intrastromal corneal ring segment migration Symptoms: Poor visual acuity • rigid contact lens intolerance Medication: — Clinical Procedure: Intrastromal corneal ring segment implantation • intrastromal corneal ring segment reimplantation Specialty: Ophthalmology Objective: Unusual or unexpected effect of treatment Background:Acute corneal hydrops refers to a rare complication of keratoconus and other ectatic disorders with potentially sight-threatening sequelae. Intrastromal corneal ring segment (ICRS) implantation is a surgical procedure performed as therapy for keratoconus when there is contact lens intolerance. ICRS migration along the tunnel made for its insertion is one of its most frequent complications. We believe this is the first published case of acute corneal hydrops and ICRS migration unfolding shortly after an uneventful ICRS implantation, and successfully managed with medical treatment and ICRS reimplantation, respectively.Case Report:A 17-year-old male, previously diagnosed with bilateral keratoconus 4 years earlier for which he underwent cross-linking surgery for both eyes 3 years prior, presented to our department for a first-time keratoconus assessment. His best-corrected visual acuity (BCVA) was 20/25 OD and 20/40 OS with rigid gas-permeable contact lenses. Due to contact lens intolerance in the OS and lack of custom-fit scleral lenses at the time, 2 ring segments (Ferrara, AJL Ophthalmic, Inc.) with an arc length of 160 degrees and 300 μm in size were implanted at a depth of 320 μm. Within 1 week, severe hydrops and ICRS migration emerged. Medical treatment provided resolution of hydrops and then ICRS reimplantation was performed without further complications, resulting in contact lens tolerance alongside a BCVA of 20/40 OS.Conclusions:Corneal hydrops is a challenging complication in ICRS implantation due to its infrequent occurrence and the severity of its potential sequelae. Prompt medical treatment and close follow-up are essential to obtain the best outcome in these instances.

Сравнительная оценка результатов комбинированного применения различных методов лечения: кросслинкинга роговицы, имплантации интрастромальных роговичных колец-сегментов и трансэпителиальной топографической фоторефрактивной кератэктомии при лечении кератоконуса

Purpose. Comparative evaluation of the results of combined use of corneal cross-linking (CXL) and implantation of intrastromal corneal ring segments (ICRS) followed by transepithelial topographic photorefractive keratectomy (ТE-topoPRK) in the treatment of keratoconus. Material and methods. The study had been conducted at the National Centre of Ophthalmology named after acad. Zarifa Aliyeva. Within the frames of the first stage of the study during 2016–2019 years: 48 patients (48 eyes) have been operated only with using CXL (first group); 48 patients (48 eyes) – with using only ICRS (second group); and 48 patients (48 eyes) – with using of combination of CXL and ICRS (ICRS first, then CXL after 24 hours) for treatment of keratoconus of II–III stages due to Amsler M. classification. After 8 months, all patients (144 eyes) underwent the second stage of treatment using ТE-topoPRK. Results. Visual acuity and corneal status 8 months later after CXL, ICRS and the combination of CXL with ICRS generally changed significantly, which confirms the achievement of the expected effect. Comparing the studied parameters after the operation in the groups of patients operated on by the CXL, ICRS methods and their combination, a significant difference was revealed only in the value of NCVA (0.22±0.04, 0.46±0.03 и 0.52±0.04; р&lt;0.05). Conclusion. The combined two-stage (with the interval of 8 months) treatment of keratoconus by implantation of intrastromal corneal rings with simultaneous corneal crosslinking followed by topographic photorefractive keratectomy is more effective than the use of these operations without combinations. Key words: crosslinking, corneal segments, keratoconus, topographic photorefractive keratectomy

Хирургический подход к лечению аметропии у пациентов с кератоконусом и катарактой

Purpose. To develop a two-stage surgical technique to the treatment of ametropia in patients with keratoconus and concomitant cataract. Material and methods. 33 patients (35 eyes) with stages II–III of non-progressive keratoconus and concomitant cataracts of various stages of maturity were operated on. The average age of the patients was 46.5±2.7 (41–63). The operations were performed according to our proposed two-stage method of treating ametropia in patients with KC and cataracts (Patent of the Russian Federation No. 2748634 of 28.05.2021). The first stage was the implantation of FE RRARA intrastromal corneal ring segments (ICRS) with thickness from 150 to 350 µm. To correct residual refractive error in 5–7 months after the 1st stage, patients underwent stage 2: cloudy lens was removed and replaced with toric posterior chamber intraocular lens (TIOL) – AcrySof IQ Toric (Alcon, USA), T-flex Toric RayOne (Rayner, UK). Results. After the first stage of the operation (ICRS implantation), the uncorrected visual acuity (NCVA) was 0.2±0.03, the best corrected visual acuity (BCVA) was 0.4±0.02. In 1 month after the 2nd stage (phacoemulsification + TIOL) NCVA was 0.64±0.11 and BCVA was 0.74±0.12. During the entire follow-up period after the surgery visual functions, refraction, and rotational stability of TIOL were stable. Conclusion. Conducting a two-stage surgical intervention in patients with keratoconus and cataracts allows to stop the progression of the disease and effectively correct the ametropia concomitant with keratoconus. Key words: keratoconus, cataract, intracorneal segments, ametropia, toric intraocular lenses

Evaluation of the effectiveness of combined staged surgical treatment in patients with keratoconus.

This study performs comparative assessment of the results of different types of two-stage surgical treatment in patients with keratoconus, including combination of corneal collagen cross-linking with intrastromal corneal ring segments followed by topography-guided photorefractive keratectomy. Prospective review of 101 patients (101 eyes) with keratoconus was performed. Patients underwent corneal collagen cross-linking (32 patients), intrastromal corneal ring segments (48 patients), and a combination of these two procedures (21 patients). Transepithelial topography-guided photorefractive keratectomy was performed as the second stage of treatment in all patients with obtained stable refractive results at 8 months after first stage. Main outcome measures were visual acuity (uncorrected distance and corrected distance) and corneal topographic indices. Comparison of the studied parameters after first stage surgical treatment between non-combined CXL and combined groups demonstrated a statistically significant difference for uncorrected distance visual acuity, corrected distance visual acuity, and cylindrical refraction values (p<0.05). We observed significant improvement of visual acuity and key corneal topographic indices after topography-guided photorefractive keratectomy in all study groups (p<0.05). In 50 (49.5%) patients customized excimer laser ablation gave the possibility of full spherical and cylindrical corrections. Ten eyes (10%) had delayed epithelial healing, no corneal stromal opacities developed. This study shows that combined two-stage surgical treatment of keratoconus, consisting of intrastromal corneal ring segment implantation with corneal collagen cross-linking followed by topography-guided photorefractive keratectomy, is clinically more effective to prevent keratectasia progression and increase visual acuity than the use of non-combined two-stage techniques.

Two-stage treatment of ametropia in patients with keratoconus and cataracts

Keratoconus (KC) is a progressive degenerative corneal disease, leads to the aberration of biomechanical and optical properties and thinning of the cornea, causes astigmatism and decreases visual acuity.Materials and methods. 33 patients (35 eyes) with stages II–III of non-progressive keratoconus and concomitant cataracts of various stages of maturity were operated on. The average age of the patients was 46.5 ± 2.7 (41–63) years old. The operations were performed according to our proposed two-stage method of treating ametropia in patients with KC and cataracts (Patent of the Russian Federation No. 2748634 of 28.05.2021). The first stage was the implantation of FERRARA intrastromal corneal ring segments (ICRS) with thickness from 150 to 350 μm. To correct residual refractive error in 5–7 months after stage 1, patients underwent stage 2: cloudy lens was removed and replaced with toric posterior chamber intraocular lens (TIOL) – AcrySof IQ Toric (Alcon, USA), T-fl ex Toric RayOne (Rayner, UK).Results and discussion. After stage 1 of the operation (ICRS implantation), the uncorrected visual acuity (NCVA) was 0.2 ± 0.03, the best corrected visual acuity (BCVA) was 0.4 ± 0.02. In 1 month after stage 2 (phacoemulsifi cation + TIOL) NCVA was 0.64 ± 0.11 and BCVA was 0.74 ± 0.12. During the entire follow-up period after the surgery visual functions, refraction, and rotational stability of TIOL were stable.Conclusions. Conducting a two-stage surgical intervention in patients with keratoconus and cataracts allows to stop the progression of the disease and effectively correct the ametropia concomitant with keratoconus.

Ferrara Rings for Visual Rehabilitation in Eyes with Keratoconus and Previous Cross-Linking Using the Ferrara Ring Nomogram.

Purpose: To report the visual, refractive and tomographic outcomes following the implantation of intrastromal corneal ring segments (ICRS) (Ferrara rings, AJL Ophthalmics, Miñano, Spain) in eyes with a history of keratoconus and corneal cross-linking using the Ferrara ring nomogram. Methods: Retrospective, interventional case series performed at the Corneoplastics Unit, Queen Victoria Hospital, East Grinstead, United Kingdom. Results: 21 eyes of 19 patients with a history of keratoconus and prior corneal collagen cross-linking had Ferrara Intrastromal Corneal Ring Segments implanted between December 2015 and October 2017. The number, thickness and length of ring segments was chosen based on the Ferrara ring company nomogram. Mean uncorrected visual acuity (UDVA) improved from 0.88 to 0.52 logMAR (p < 0.001). Mean corrected visual acuity (CDVA) improved from 0.47 to 0.36 logMAR (p = 0.046). The percentage of eyes achieving 20/40 UDVA and CDVA increased from 5% to 38% and from 38% to 67%, respectively. Of the eyes, 52.3% gained at least two lines of CDVA. The spherical equivalent improved from −7.51D to −3.76D (p < 0.001) and the refractive astigmatism magnitude improved from 5.14D to 2.76D (p = 0.004). There were significant improvements in the corneal tomography with mean keratometry (KM) improving from 50.40D (3.53) to 48.24D (3.00) (p = 0.01) and keratometric astigmatism magnitude improving from 5.14D (2.91) to 2.76D (1.67) (p = 0.004). Conclusion: Insertion of Ferrara rings in keratoconic eyes with a history of prior cross-linking using the company nomogram results in significant improvements in visual, refractive and tomographic outcomes.