Contact lens assisted corneal cross linking in thin ectatic corneas – A review

Srivatsa, Sanjana; Jacob, Soosan; Agarwal, Amar

doi:10.4103/ijo.ijo_2138_20

Cited by 25 publications

(27 citation statements)

References 30 publications

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“…While CXL is an effective treatment modality for progressive KC, there are numerous areas remaining for the improvement and expansion of this procedure for patients beyond the approved protocols. For example, in the United States, conventional CXL is approved only in eyes with a corneal thickness of at least 400 microns [ 10 ], which excludes a significant number of KC patients who may potentially benefit from this therapy. Further, painful epithelial defects with secondary corneal infection and scarring resulting from epithelial removal prior to CXL treatment have also been reported.…”

Section: Discussionmentioning

confidence: 99%

“…As such, a significant number of patients with mild disease who would benefit from CXL may not meet the established criteria for CXL until, ironically, the disease worsens. Additional criteria must also be satisfied before qualifying for CXL: patients older than 16 years, with a minimum corneal thickness (CCT) of 400 microns, maximal keratometry < 60 D, and no other known corneal disease [ 10 ]. Finally, there are a growing number of patients with post-LASIK ectasia [ 11 ] who may also benefit from CXL to arrest disease progression but may not qualify due to the criteria mentioned above.…”

Section: Introductionmentioning

confidence: 99%

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Collagen Crosslinking for Keratoconus: Cellular Signaling Mechanisms

et al. 2023

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Collagen crosslinking (CXL) is a widely used treatment to halt the progression of keratoconus (KC). Unfortunately, a significant number of patients with progressive KC will not qualify for CXL, including those with corneas thinner than 400 µm. The present study aimed to investigate the molecular effects of CXL using in vitro models, mirroring the normal, as well as thinner corneal stroma seen in KCs. Primary human corneal stromal cells were isolated from healthy (HCFs) and keratoconus (HKCs) donors. Cells were cultured and stimulated with stable Vitamin C resulting in 3D self-assembled extracellular matrix (ECM), cell-embedded, constructs. CXL was performed on (a) thin ECM with CXL performed at week 2 and (b) normal ECM with CXL performed at week 4. Constructs without CXL served as controls. All constructs were processed for protein analysis. The results showed modulation of Wnt signaling, following CXL treatment, as measured by the protein levels of Wnt7b and Wnt10a, correlated to the expression of α-smooth muscle actin (SMA). Further, the expression of a recently identified KC biomarker candidate, prolactin-induced protein (PIP), was positively impacted by CXL in HKCs. CXL-driven upregulation of PGC-1 and the downregulation of SRC and Cyclin D1 in HKCs were also noted. Although the cellular/molecular impacts of CXL are largely understudied, our studies provide an approximation to the complex mechanisms of KC and CXL. Further studies are warranted to determine factors influencing CXL outcomes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Collagen Crosslinking for Keratoconus: Cellular Signaling Mechanisms

et al. 2023

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Section: Discussionmentioning

confidence: 99%

“…13,15 The success of this method remains controversial, and several modifications in regard to the choice of CL material and the method of riboflavin application during UV irradiation have been proposed to increase the efficacy of this technique. 16,23 A recent study by Wollensak et al 16 compared the biomechanical changes after CL-CXL using three types of CLs (Air Optix Aqua, SofLens, and Galifa) with different degrees of hydrophilicity (33%, 59%, and 72%, respectively) in porcine corneas using corneal strip extensometry. In the silicone hydrogel CL (Air Optix Aqua) group, at 8% strain, Young's modulus and stress were 92% and 86% of the standard CXL protocol, respectively, whereas the other two groups with hydrophilic CLs achieved a two-thirds stiffening effect of the standard protocol.…”

Section: Discussionmentioning

confidence: 99%

Comparison of safety and efficacy of silicone hydrogel contact Lens-assisted CXL and accelerated CXL in keratoconus patients with thin corneas

Uysal

Özmen

Yuksel

et al. 2022

European Journal of Ophthalmology

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Purpose To evaluate the efficacy and safety of silicone hydrogel contact lens-assisted corneal cross-linking (CL-CXL) and compare 12-month visual and topographic outcomes with accelerated CXL using hypo-osmolar riboflavin (A-CXL) in keratoconus patients with thin corneas (below 400 μm with epithelium). Methods This retrospective study included 27 eyes of 27 keratoconus patients who underwent CL-CXL (n = 14) or A-CXL (n = 13). Uncorrected and corrected distance visual acuity (UDVA and CDVA) and data obtained from corneal topography were analyzed at baseline and again at 6- and 12-month follow-ups. Corneal demarcation line depth (DLD) was measured at one month, and changes in the corneal endothelial cell density (ECD) at 12 months were also assessed. Results Mean UDVA improved significantly in both groups at 12 months (all p < 0.05). Maximum keratometry (K-max) decreased by 1.04 ± 1.90 D in the CL-CXL group and by 0.87 ± 1.89 D in the A-CXL group at 12 months, which was not statistically significant (all p>0.05). Total corneal higher-order aberrations (HOAs) analysis showed a significant improvement in only the CL-CXL group at 12 months (p = 0.041). Average DLD was 227.18 ± 65.60 μm in the CL-CXL group and 245.30 ± 66.84 μm in the A-CXL group (p = 0.275). No significant change in ECD was found in either group (all p>0.05). Mean changes in UDVA, CDVA, K-max, K-mean, HOAs, and ECD were not statistically significant between the groups (all p>0.05). Conclusions Silicone hydrogel CL-assisted CXL seems as effective as A-CXL in halting keratoconus progression in thin corneas with no side effects during the one-year follow-up period.

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“…Hyposmolar riboflavin solutions have been used to swell the corneal stroma by more than 400 µm to treat thinner corneas, but without consistent evidence. Other procedures have been described as treatment of thin corneas, such as the accelerated cross-linking nomograms, the sub-400 protocol, the M nomogram for standardized treatment of thin corneas, contact-lens-assisted treatments, and the smile-lenticule-assisted epi-off CXL [43][44][45].…”

Section: Discussionmentioning

confidence: 99%

Topo-Pachimetric Accelerated Epi-On Cross-Linking Compared to the Dresden Protocol Using Riboflavin with Vitamin E TPGS: Results of a 2-Year Randomized Study

Caruso

Epstein

Troiano

et al. 2021

JCM

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In the present study (clinical trial registration number: NCT05019768), we compared the clinical outcome of corneal cross-linking with either the standard Dresden (sCXL) or the accelerated custom-fast (aCFXL) ultraviolet A irradiation protocol using riboflavin–D-α-tocopheryl poly(ethylene glycol)-1000 succinate for progressive keratoconus. Fifty-four eyes of forty-one patients were randomized to either of the two CXL protocols and checked before treatment and at the 2-year follow-up. The sCXL group was subjected to CXL with 30 min of pre-soaking and 3 mW/cm2 UVA irradiation for 30 min. The aCFXL group was subjected to CXL with 10 min of pre-soaking and UVA irradiation of 1.8 ± 0.9 mW/cm2 for 10 min ± 1.5 min. In both groups, a solution of riboflavin–vitamin E TPGS was used. Uncorrected distance visual acuity, corrected distance visual acuity, pachymetry, Scheimpflug tomography, and corneal hysteresis were performed at baseline and after 24 months. Both groups showed a statistically significant improvement in corrected distance visual acuity, and keratometric and corneal hysteresis compared to baseline conditions; no statistically significant differences in outcomes between the two groups were observed. Improvement in refractive, topographic, and biomechanical parameters were observed after sCXL and aCFXL, making the riboflavin–VE-TPGS solution an effective option as a permeation enhancer in CXL procedures. Deeper stromal penetration of riboflavin could be complemented by photo-protection against UVA and free radicals formed during photoinduced processes.

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Contact lens assisted corneal cross linking in thin ectatic corneas – A review

Cited by 25 publications

References 30 publications

Collagen Crosslinking for Keratoconus: Cellular Signaling Mechanisms

Collagen Crosslinking for Keratoconus: Cellular Signaling Mechanisms

Comparison of safety and efficacy of silicone hydrogel contact Lens-assisted CXL and accelerated CXL in keratoconus patients with thin corneas

Topo-Pachimetric Accelerated Epi-On Cross-Linking Compared to the Dresden Protocol Using Riboflavin with Vitamin E TPGS: Results of a 2-Year Randomized Study

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