Corneal Cross-linking Research Articles

Glycosaminoglycans and collagen fibril distribution at various depths of the corneal stroma of normal and CXL treated rats

Corneal collagen cross-linking (CXL) is widely used to treat keratoconus and ecstatic corneal disorders. The present studies were carried out to investigate the distribution of glycosaminoglycans (GAGs) and collagen fibril (CF) at different depths of the normal and CXL treated corneal stroma of four week old rats 7 days after standard CXL application. Ten Wistar rats’ corneas were used for the study. The epithelium of the cornea from the left eye of each rat was removed and treated with standard CXL application using riboflavin and Ultraviolet-A (UVA) (3 mW/cm2 for 30 min). The cornea from the right eye was used as the control cornea. The cornea was removed from the eye and processed for transmission electron microscopy. A bottom mounted Quemesa camera was used to capture digital images and these images were analysed using iTEM software. In the control cornea, the GAGs area size was not significantly different in the anterior, middle, and posterior stroma. In the CXL treated rats the GAGs area size gradually increased from the anterior to the posterior stroma whereas the spacing between the GAGs gradually decreased. There were very large GAGs present in the posterior stroma of the CXL treated rats. When comparing the control and CXL cornea, the GAGs area in the CXL cornea was significantly higher and inter-GAGs-spacing was smaller than in the control cornea. In the control cornea, the collagen fibrils diameter was higher in the anterior stroma and lowest in the posterior stroma. In the CXL treated cornea, the CF diameter and the interfibrillar spacing gradually decreased from the anterior to the posterior stroma. On comparison between the control and the CXL treated cornea, the interfibrillar spacing was significantly smaller in the CXL treated cornea than the control cornea in the anterior, middle, and posterior stroma but there was no difference in the diameter. The CXL treatment significantly increased the GAGs area and decreased the inter-GAGs-spacing, and inter–CF–spacing. This could be due to the gradual decline in the availability of riboflavin, UVA, and oxygen in the middle and posterior stroma. Further studies are required to investigate the role of keratan sulphate and chondroitin sulphate by using monoclonal antibodies with immunogold technique.

Safety and efficacy of a combined treatment with corneal collagen cross-linking and lamellar keratoplasty in patients with keratitis

Introduction and Aim: There is a link between an increase in eye infections, environmental deterioration, increased intensity of eye surgery, and the diversification of diagnostic techniques and the development of corneal disease and eye injuries. This study aims to assess the safety and efficacy of a complex treatment for corneal ulcers (keratitis) that combines corneal collagen cross-linking (CXL) with lamellar keratoplasty (LK). Materials and Methods: This study consisted of 28 eyes from 28 patients with keratitis. All patients were divided into the main and control groups; each group had 14 patients (14 eyes). All patients underwent a standard ophthalmological examination, which included visometry without correction, with correction, tonometry, biomicroscopy, and ophthalmoscopy. Results: High postoperative astigmatism was found in 50% of cases (7 eyes) of the control group and in 21.4% of cases (3 eyes) of the main group over the 1-6 months follow-up period. Both groups visual acuity development dynamics were very similar from the three-month to three-year follow-up period, and the average visual acuity with maximal correction was between 0.4 - 0.5. Conclusion: Ultraviolet radiation exposure during CXL increases the graft's strength, the recipient's corneal tissue in the suture area, and the pathological flora's direct bactericidal and virucidal effects, reducing infectious process recurrences.

Alternative methods of surgical treatment of keratoconus

The introduction of early diagnostic methods for keratoconus into clinical practice has become the basis for the development of surgical treatment techniques for this pathology, such as corneal collagen crosslinking and interlamellar keratoplasty with implantation of intrastromal segments. The article analyzes the results of research by Russian and foreign specialists in these areas and presents the data on the combination of SMILE surgery and corneal crosslinking, the Rome protocol of corneal crosslinking, modifications of interlamellar keratoplasty, the use of femtosecond laser technologies, and some pilot studies. Modern requirements for ophthalmological care require a personalized approach to each patient, and therefore the surgeon should have a wide range of surgical methods of treatment applicable to different patient cohorts. The described methods of treatment, according to the authors, are the most promising.

A comprehensive review on corneal crosslinking.

Corneal crosslinking (CXL) represents a paradigm shift in the management of corneal ectatic disorders. Before CXL was introduced, patients would need specialty contact lenses and possible corneal transplantation. CXL involves a biochemical reaction in which ultraviolet A light is used in conjunction with Riboflavin to form crosslinks in between corneal stromal collagen. This leads to strengthening and stabilizing of the collagen lamellae, resulting in mechanical stiffening of the cornea. Multiple protocols have been proposed including epithelium on versus off and varying light intensity and duration of treatment. All protocols appear to be safe and effective with few reported complications including infection, stromal haze, scarring, and endothelial toxicity. Overall, CXL has demonstrated to halt the progression of the disease clinically and in keratometry readings and improve the quality of life for patients. It is a minimally invasive, cost-effective procedure that can be performed in an outpatient setting with a fast recovery time and long-lasting results.

Assessment of Corneal Cross-Linking Effect on Progressive Keratoconus by Using the ABCD Grading System.

The aim of this study was to assess changes in corneal parameters 6 months after corneal cross-linking for progressive keratoconus, using the ABCD system. This retrospective study was conducted at the King Khaled Eye Specialist Hospital (Riyadh, Saudi Arabia) between January 1 and July 30, 2022. This study included 16 eyes of 16 patients with keratoconus who underwent corneal cross-linking at the same hospital and were at least 18 years old. At least one preoperative (T0) and one postoperative examination was performed for each patient. Six months after the procedure (T1), patients underwent corneal tomography. The parameters A, B, C, and D were also evaluated. Other parameters monitored included maximal keratometry (Kmax) (K1 and K2), Belin/Ambrósio Enhanced Ectasia Display, and index vertical asymmetry. The progression of ectasia was identified by a consistent change in at least two parameters: steepening of the anterior corneal surface or the posterior corneal surface, thinning or an increase in the rate at which the corneal thickness changed from the periphery to the thinnest point, where the magnitude of the change was greater than the normal noise of the testing system. Among the patients, 68.8% were men. The patients' average age was 25.8±5 years. Throughout the 6-month postoperative follow-up, parameters A, B, and C exhibited substantial changes (P = 0.000 for parameters A, B, and C). Parameter A increased 6 months after surgery, whereas parameters B and C decreased. Preoperatively and 6 months after surgery, Kmax, K1, and Belin/Ambrosio-enhanced ectasia demonstrated substantial differences. However, parameter D, K2, and the average pachymetric progression index did not change significantly. Anterior and posterior corneal curvatures and corneal thickness profiles can be useful for monitoring the progression of keratoconus and the success of the corneal cross-linking operation.

Keratoconus: imaging modalities and management.

Keratoconus (KCN) is characterized by gradual thinning and steepening of the cornea, which can lead to significant vision problems owing to high astigmatism, corneal scarring, or even corneal perforation. The detection of KCN in its early stages is crucial for effective treatment. In this review, we describe current advances in the diagnosis and treatment of KCN. This narrative review focuses on recent advancements in the diagnosis and treatment of KCN, especially evolving approaches and strategies. To ensure the inclusion of the most recent literature, relevant publications discussing advanced imaging techniques and treatment options for KCN were extensively gathered from the PubMed/MEDLINE and Google Scholar databases. The following index terms and keywords were used for the online search: keratoconus, diagnosis of keratoconus, advances in the diagnosis of keratoconus, topography or tomography, anterior segment optical coherence tomography, treatment of keratoconus, advances in the treatment of keratoconus, collagen crosslinking, intrastromal ring, keratoplasty, and new techniques in keratoconus. Various screening methods such as corneal topography, tomography, anterior segment optical coherence tomography, and assessment of corneal biomechanics have been developed to identify KCN in its early stages. After diagnosis, KCN management focuses on preventing disease progression. Corneal collagen crosslinking is a minimally invasive treatment that can slow or stop the progression of the condition. Recent research has also explored the use of copper sulfate eye drops (IVMED-80) as a noninvasive treatment to prevent the progression of KCN. Current treatment options for visual improvement include scleral lenses, intracorneal ring segments, corneal allogeneic intrastromal ring segments, and deep anterior lamellar keratoplasty. Recently, novel alternative procedures, such as isolated Bowman layer transplantation, either as a corneal stromal inlay or onlay, have demonstrated encouraging outcomes. Artificial intelligence has gained acceptance for providing best practices for the diagnosis and management of KCN, and the science of its application is contentiously debated; however, it may not have been sufficiently developed. Early detection and advancements in screening methods using current imaging modalities have improved diagnosis of KCN. Improvement in the accuracy of current screening or diagnostic tests and comparison of their validities are achievable by well-designed, large-scale, prospective studies. The safety and effectiveness of emerging treatments for KCN are currently being investigated. There is an ongoing need for studies to track progress and evaluate clinicians' knowledge and practices in treating patients with KCN. Artificial intelligence capabilities in management approach considering the currently available imaging modalities and treatment options would best benefit the patient.

Comparative analysis of clinical and functional parameters in patients with stable stage II-III keratoconus after implantation of corneal segments and fitting of scleral rigid contact lenses

This study compares the effect of implantation of intrastromal corneal ring segment (ICRS) and fitting of individual scleral rigid contact lenses (RCLs) on visual functions in patients with stage II-III KC after previously performed corneal collagen cross-linking. The Helmholtz National Medical Research Center of Eye Diseases examined and treated 34 patients (69 eyes) aged 18 to 33 years with stage II-III KC. The study included patients who had previously undergone standard corneal collagen cross-linking. Depending on the type of optical correction, the patients were divided into two groups: patients in group 1 underwent ICRS implantation using a femtosecond laser; patients in group 2 were fitted with individual scleral RCLs. Improvement in clinical and functional parameters was observed in both groups. A higher clinical and functional result was achieved in group 2. For patients with stable stage II-III KC, it is advisable to recommend fitting of individual scleral RCLs for visual rehabilitation.

Effect of Corneal Collagen Crosslinking with Riboflavin in Patients of Progressive Keratoconus: A Prospective Cohort Study

Introduction: Keratoconus is a non inflammatory disease characterised by progressive corneal thinning that results in a cone-like ectasia, irregular astigmatism, and decreased vision. Advanced disease can result in corneal scarring and blindness, necessitating penetrating keratoplasty. The only treatment believed to have the ability to stop or decrease the progression of keratoconus is Collagen Cross-Linking (CXL). Aim: To evaluate the efficacy of corneal collagen cross-linking with riboflavin (C3R) in patients with keratoconus by studying the outcomes in terms of Uncorrected Visual Acuity (UCVA), Best Corrected Visual Acuity (BCVA), manifest refraction, and corneal topography. Materials and Methods: A hospital-based prospective cohort study was conducted at the Regional Institute of Ophthalmology, Government Medical College, Thiruvananthapuram, Kerala, India from June 2017 to June 2018. Fifteen eyes of 12 patients who underwent corneal collagen cross-linking for progressive keratoconus were included. Routine ophthalmological examinations was done for all patients. Patients under the age of 35 years with progressive keratoconus, an average K value not exceeding 60 D, and who had not undergone any other surgical modalities of treatment were included in the study. Patients with scarred cornea or hydrops, active ocular infection, or pachymetry <400 µm were excluded. Detailed informed consent was obtained from all patients before surgery. Preoperative UCVA, BCVA cylinder, Spherical Equivalent (SE), and topography values were obtained. All patients were followed-up at three and six months postoperative period to look for changes in UCVA, BCVA, manifest refraction, and corneal topography. Data were expressed as the mean±Standard Deviation (SD) pre- and postoperatively and analysed statistically using the paired t-test, with p<0.05 considered statistically significant. Analysis was conducted using Statistical Package for Social Sciences (SPSS) version 16.0. Results: On follow-up at six months post-treatment, UCVA (log MAR) improved from 0.87±0.40 to 0.65±0.35 (p-value=0.001), and BCVA (log MAR) changed from 0.37±0.21 to 0.17±0.22 (p-value=0.001). K max decreased from 54.90±6.05 to 52.67±5.02 (p-value=0.001), and K min decreased from 48.14±4.24 to 45.93±4.07 (p-value=0.001). Astigmatism and SE also showed statistically significant improvement post-procedure (p-value 0.001 and 0.002, respectively). Astigmatism reduced from -3.50±1.58 to -2.90±1.37. SE reduced from -4.93±3.92 to -4.28±3.48. No significant complications were noted in any of the patients. Conclusion: The CXL is an effective procedure for stabilising the progression of keratoconus, thus reducing the burden of preventable blindness and the need for keratoplasty.

The biomechanical e‐staging—In vivo assessment of corneal biomechanics in keratoconus

Aims/Purpose: Keratoconus (KC) is biomechanically characterized by a decreased resistance to deformation when compared to healthy corneas. The aim of this presentation is to give an overview about the development and clinical application of the recently introduced Homburg Biomechanical E‐Staging (BEST) for KC.Methods: The Corvis ST (Oculus, Germany) non‐contact pneumotonometer measures the corneal deformation after applying a standardized air puff. It calculates the quasi‐binary indices Corvis Biomechanical Index (CBI) and Tomographic Biomechanical Index (TBI) to separate healthy from ectatic corneas, without, however providing a biomechanical KC severity stage. The Homburg BEST based on the linearized CBI provides information about biomechanical KC severity in form of E‐stages 0 to 4, thus augmenting the existing tomographic ABCD KC classification by including corneal biomechanics. Several studies and results about the development and clinical application of the Homburg BEST are presented.Results: The Homburg BEST was developed based on two independent KC datasets (Homburg: n = 448, Milano/Rio: n = 860). Since 2022, it has been integrated into the Corvis ST software, thus providing a biomechanical KC severity and progression assessment. The software based on several individual biomechanical parameters indicates KC progression like tomographic progression parameters. However, it is influenced by corneal thickness measurements, increases within the first postoperative months after corneal crosslinking (CXL) and indicates postoperative KC stabilization more than 1 year after CXL. Intracorneal ring segment implantation permanently affects corneal thickness in the midperiphery and contributes to slightly higher postoperative BEST values.Conclusions: Although with limitations, the Homburg BEST enables a biomechanical staging and progression assessment in KC by considering several biomechanical parameters as an addition to the previously purely tomographic or even topographic analysis.

Application of Rapid Corneal Collagen Crosslinking (CXL) Combined with FS-LASIK in the Diagnosis and Treatment of Myopia

Application of Rapid Corneal Collagen Crosslinking (CXL) Combined with FS-LASIK in the Diagnosis and Treatment of Myopia

Evaluation of ocular surface features following corneal collagen cross-linking treatment in keratoconus patients: 24-month results

Evaluation of ocular surface features following corneal collagen cross-linking treatment in keratoconus patients: 24-month results

Silicon-dried corneal graft crosslinking as a means to increase the effectiveness of urgent keratoplasty

Purpose: to evaluate the effectiveness of silicon-dried cornea, previously subjected to corneal collagen UVA crosslinking, for urgent keratoplasty.Material and methods. 28 patients (16 males, 12 females), diagnosed with perforating corneal ulcer of various etiologies, underwent penetrating keratoplasty for eye-preserving purposes. 14 patients (the main group) underwent transplantation of a silicon-dried cornea, previously subjected to corneal collagen crosslinking according to the standard (Dresden) protocol while the remaining 14 patients (comparison group) underwent penetrating keratoplasty with not pre-treated silicon-dried cornea. In the postoperative period, we measured the time of primary complete epithelization of the graft and assessed the presence/absence of ulcers and erosions of the corneal graft 1, 3, 6 and 12 months after the discharge from the hospital. For this purpose, all patients underwent corneal biomicroscopy with corneal surface preliminary stained with a 1% sodium fluorescein solution.Results. Complete epithelization in both the main group and the comparison group was found to take place, on average, at the same time after surgery. However, over the entire observation period, the main group showed fewer relapses of ulcers and corneal graft erosions than the comparison group.Conclusion. The use of silicon-dried cornea, subjected to corneal collagen cross-linking, increases the effectiveness of perforated corneal ulcer treatment in emergency surgical care.

Прогнозирование клинико-морфофункциональных результатов кросслинкинга роговичного коллагена у детей

Purpose. To develop methods of predicting corrected distance visual acuity (CDVA) and minimum corneal thickness (СT) 12 months after crosslinking in children using preoperative data. Material and methods. This study was conducted on 30 eyes in 30 patients (21 (68%) boys, 9 (32%) girls) with a median age of 16 [15; 17] years (from 12 to 17 years) who underwent the procedure of accelerated «epi-off» crosslinking. All patients underwent standard and special examination, including high-tech methods (Sheimpflug camera). Multiple regression was used to develop models for predicting CDVA and the minimum thickness of the cornea. The follow-up period was 12 months. Results. A model was developed for predicting CDVA 12 months after crosslinking, depending on the CDVA data and keratometry K2 before surgery, described by the formula: CDVA12 months after = –0,833 + 0,907 × CDVA before + 0,020 ×K2 (Adj R² =0.739, p<0.000). A model has been developed for predicting the minimum СT 12 months after crosslinking in children, depending on the data of the minimum СT and CDVA before surgery, described by the formula СT12 months after = 49,868 + 0,866 ×TRbefore + 14.551 × CDVAbefore (Adj R² =0,950 (p<0,001). Conclusion. The developed methods for assessing the clinical and morphofunctional results of corneal collagen crosslinking in children can significantly help in choosing the optimal tactics after the treatment of keratoconus in children using crosslinking. Key words: keratoconus, keratoconus in children, corneal collagen crosslinking, artificial intelligence, multiple regression

Fungal Keratitis. Part 2. Diagnosis and Treatment

The problem of diagnosis and treatment of fungal keratitis (FK) is very acute. Due to the slow development of clinical features and the absence of clear pathognomonic signs, this disease is characterized by a late start of the introduction of adequate etiotropic therapy. Often this leads to the development of large corneal defects requiring surgical intervention. Diagnostic methods are divided into invasive and non-invasive. Invasive methods include the study of scrapings from the surface of the cornea from the site of ulceration, biopsy of the corneal stroma or moisture of the anterior chamber using microscopic, cultural methods or polymerase chain reaction (PCR). Non-invasive techniques include confocal microscopy and optical coherence tomography of the anterior segment. They allow you to dynamically monitor the course of the pathological process and the response to ongoing therapy. Promising methods are also the detection of (1,3)-β-D-glucans in tears, the detection of the pathogen using MALDI-TOF MS. The gold standard for the treatment of FK in the world is the topical application of 5 % Natamycin (approved by the FDA, but not available in Russia). Fluconazole, Voriconazole and Amphotericin B, available in Russia, are also widely used, but their topical use is possible only in off label format. In the presence of hypopyon or an increase in the size and depth of the infiltrate, despite ongoing treatment, immediate surgical treatment is required in order to preserve the integrity of the eyeball. Such treatments include penetrating keratoplasty, anterior lamellar keratoplasty, amniotic membrane transplantation, conjunctival flaps, corneal collagen cross-linking (with unproven efficacy), and argon laser. A promising method for the treatment of FK can be the use of Ag(10 %):InP/ZnS MPA quantum dots as monotherapy or as a bioconjugate with known antifungal drugs.

Photophysical and photodynamic analysis of different formulations of riboflavin

Background: Riboflavin (Rb) has been used in the ophthalmological procedure known as corneal cross-linking (CXL). Pathologies requiring this treatment include keratoconus, corneal ectasia, and infectious keratitis. Rb is instilled via different molecules that are transported into the tissues. However, each vehicle imparts different properties that alter the photodynamic behavior of Rb, leading to variable concentrations of free radicals within the medium. The objective of this study was to measure the concentrations of free radicals produced by commonly used Rb formulations. To determine the free radical production level of each formulation, L-tryptophan (L-Tryp) was used as a model substrate because it can be efficiently photo-oxidized.
 Methods: We investigated the photodegradation of L-Tryp and its kinetics upon light exposure. The spectra were recorded using a Shimadzu UV-1800 PC spectrophotometer and a Cary Eclipse fluorescence spectrophotometer. A high-power solid-state LED light source was used for irradiation. L-Tryp degradation was performed using a 9-W LED lamp, and steady-state photolysis was conducted in quartz cells. The observed rate constants for L-Tryp degradation were determined by analyzing the changes in absorbance and fluorescence intensity. Data analysis was performed using Origin software.
 Results: We examined the characteristics of the photophysical and photodynamic action of the carriers in different commercially available Rb formulations. These included a) Rb with dextran, b) Rb without dextran, c) VibeX Rapid® (hydroxypropylmethylcellulose as a vehicle), d) Trans-Epithelial Kit (I) (sodium chloride as a vehicle), and e) Trans-Epithelial Kit (II) (benzalkonium chloride as a vehicle), using L-Tryp as a model substrate, and focusing on absorption and emission spectra. VibeX Rapid® exhibited the highest photo-degradation constant. The study affirmed the stability of Rb formulations for CXL and highlighted the efficacy of VibeX Rapid® in L-Tryp photo-oxidation and this rationalizes its current use as a CXL agent.
 Conclusions: We demonstrated that formulations for transport of Rb are of crucial importance in CXL applications. Rb in the VibeX Rapid® formulation is more effective in generating photo-degradation, and this reflects its superior performance in CXL. Future experiments should be designed and conducted to quantitatively differentiate the production of free radicals. Studies involving human participants could shed light on the clinical efficacy and safety of the available Rb formulations.

Investigation of the safety and effectiveness of accelerated contact lens-assisted corneal cross-linking (A-CACXL) in thin corneas.

To determine the safety and effectiveness of accelerated contact lens-assisted corneal crosslinking (A-CACXL) as an alternative method in progressive keratoconus patients with thin corneas. In our retrospective study, 31 eyes from 25 patients with progressive keratoconus that with a minimum corneal thickness of 400 µm or less after epithelial debridement underwent A-CACXL with a follow-up 6 months or more were included. The main outcome measures were uncorrected distance(UDVA) and corrected distance(CDVA) visual acuities, manifest sphere(D) and manifest cylinder(D) refraction values, K1(D), K2(D), Kmax(D), mean keratometry(D) values, minimum corneal thickness(μm) and endothelial cell count(cells/mm2). These outcome measurements were statistically analyzed at preoperative and postoperative 1 month, 3 months, and 6 months follow-ups. 31 eyes from 25 patients with the mean follow-up period of 7.7 ± 2.7 months were included. Data revealed a significant increase in CDVA(p = 0.053). There is no statistically significant change in UDVA, K1, mean keratometry, mean manifest sphere value, minimum corneal thickness and endothelial cell count .(respectively p:0.053, p: 0.333, p: 0,129, p:0.490, p: 0,467, p:0.035, p:0.102). There is a statistically significant decrease in the K2, Kmax and mean manifest cylinder values.(respectively p: 0,030, p < 0,001, p < 0,001). A-CACXL method is a safe and effective method to stop keratoconic progression and improve functional vision in patients with thin corneas. However, larger randomised controlled studies are needed to validate these findings.

Ethnicity, Progressive Keratoconus, and Outcomes after Corneal Cross-Linking in Southern Israel.

To assess clinical outcomes of corneal cross-linking (CXL) intervention in a population diagnosed with progressive keratoconus. This single-center retrospective cohort study included consecutive patients who underwent standard CXL or accelerated CXL for progressive keratoconus at a major teaching hospital in southern Israel between January 2015 and December 2019. Patients' medical files were reviewed, and pre-operative and post-operative data regarding demographics and clinical and tomographic characteristics were extracted and analyzed. This study included 166 patients (representing 198 eyes), out of which 98 patients (123 eyes) were ethnically Bedouin, and 68 patients (75 eyes) were ethnically Jewish. Overall, 126 patients (144 eyes) had a follow-up of at least 12 months (16.84 ± 5.76). The mean patient age was 20.62 ± 7.1 years old. There were significant baseline differences between the two ethnic groups in best-corrected visual acuity (BCVA; p < 0.001), uncorrected visual acuity (UCVA; p < 0.001), mean keratometry (p = 0.028), and corneal thickness (p < 0.001). Significant changes in BCVA, UCVA, and pachymetry parameters within each group were found after 12 months. Negative binomial regression analysis showed a maximal keratometry below 55D (RR = 1.247, p < 0.001), and a standard CXL procedure (RR = 1.147, p = 0.041) are significantly related to the stability of KC after 12 months. However, the effect size of the origin of patients is negligible (RR = 1.047, p = 0.47). In this study, the Bedouin population suffered from more progressive keratoconus when compared to the Jewish population. CXL was significantly effective in improving BCVA and UCVA in both groups after 12 months of follow-up. The effect size of the origin of patients on the stability of KC was found to be negligible.

Novel Technique to Improve the Efficacy of Corneal Cross Linking in Cases of Post LASIK Ectasia [Letter

Novel Technique to Improve the Efficacy of Corneal Cross Linking in Cases of Post LASIK Ectasia [Letter

Managing Corneal Astigmatism

Corneal astigmatism is a refractive error that creates an asymmetric blur in the vision. Corneal astigmatism can arise from trauma, disease, following surgery, or be congenital. In assessing corneal astigmatism, a decision should be made as to whether the astigmatic pattern is regular or irregular. Regular astigmatism is most common, can be congenital and is easier to manage due to the uniform nature of the changes in corneal power. Irregular astigmatism is commonly caused by trauma disease and may be induced by surgery. Corneal astigmatism can sometimes be prevented or its magnitude or irregularity reduced. Using sealants following corneal trauma can reduce suture-induced astigmatism. Management options for corneal astigmatism include glasses, contact lenses, and surgery such as incisional procedures, refractive laser surgery, intraocular lenses or rarely corneal grafting. In children with corneal astigmatism, management of amblyopia is often needed. For keratoconus, which is often a cause of irregular astigmatism, corneal cross-linking should be considered to stabilize progressive disease prior to refractive management. New treatment modalities are needed to enable more patients with corneal astigmatism to have improved vision

Observation and assessment of the immediate use of a silicon hydrogel contact lens after transepithelial corneal cross linking: a prospective study

BackgroundTransepithelial corneal crosslinking (CXL) is a novel surgical approach for the treatment of keratoconus, which is a bilateral asymmetrical ophthalmological disease accompanied by progressive corneal ectasia. Silicon hydrogel (SiH) contact lenses have been extensively used in clinical ophthalmologic medicine, as a postoperative ophthalmological intervention. However, the ideal lens application duration after transepithelial CXL remains uncertain. Here, we aimed to investigate the effects and comfort of immediate corneal contact lens use after transepithelial CXL for keratoconus.MethodsIn this prospective study, 60 patients with keratoconus who underwent transepithelial CXL treatment were enrolled from September 2021 to January 2023 with a male:female ratio of 39:21, and an average age of 25.42 ± 5.47 years. The patients were divided randomly into two groups: group A contained 30 patients wearing silicone hydrogel contact lenses for 7 days postoperatively, and group B contained 30 patients wearing the same contact lenses for 3 days.Ten subjective ophthalmologic symptoms were surveyed by the patients, including pain, photophobia, foreign body sensation, tearing, burning, blurred vision, dry eyes, difficulty opening the eyes, astringency, and stinging. Ophthalmologic signs, including corneal edema and conjunctival congestion, were recorded by a single clinician on postoperative days 1, 3, and 7.ResultsEach surgical procedure was readily performed without complications, and both groups postoperative day 7 (P = 0.04), where group B scored (0.01 ± 0.41) lesser than group A (0.12 ± 0.29), whilst corneal edema in both groups recorded significantly different on postoperative days 5 and 7 (group A demonstrated the result of 0.17 ± 0.14 and 0.08 ± 0.11 for the respective days, whereas group B indicated 0.10 ± 0.13 and 0.03 ± 0.07 at the corresponding times).ConclusionsImmediate use of silicone hydrogel corneal lenses after transepithelial CXL effectively alleviates postoperative ocular distress, particularly with a three-day use period as the ideal duration.