RESUMO
Myopia is becoming increasingly severe, and studies have shown that the cellular mechanics of scleral fibroblasts are altered following myopia. Scleral UVA-Riboflavin Collagen Crosslinkingï¼sCXLï¼ is a promising treatment for myopia prevention and control of axial growth. Understanding the mechanical properties of scleral fibroblasts is crucial, as it influences the cellular response and limits the extent of molecular deformation triggered. Thus, our study aimed to investigate the effect of mechanical properties of scleral fibroblasts in a lens-induced myopic guinea pig model following sCXL. For this purpose, we performed the 0.1% riboflavin/UVA scleral crosslinking (365 nm,3 mW/cm2,30 min) in the right eyes of guinea pigs in Group CXL. In Group LIM, the right eyes were only administrated negative lens for 6 weeks. No treatment was performed in both eyes of the guinea pigs in group Control. The scleral fibroblasts were isolated and cultured from the scleral tissue at the cross-linking area in Group CXL and the corresponding area in Group LIM and control. The curve of the length of microtubules inhaled by cells under negative pressure was measured by a microaspiration-based isolation technique, and the equilibrium Young's modulus and apparent viscosity of scleral fibroblasts were calculated by formula fitting. The equilibrium Young's modulus of scleral fibroblasts in group CXL was significantly lower than that in the LIM group (P < 0.01, two-sample t-test between pairsï¼, and there was no significant difference between groups CXL and control. The results show that sCXL can effectively moderate the phenomenon that scleral fibroblasts are not easy to deform after myopia. The apparent viscosity modulus in the CXL group was higher than the groups' control and LIM. Taken together, our data demonstrate the biomechanics of the scleral fibroblasts altered after Riboflavin/UVA scleral collagen cross-linking in a lens-induced myopia model.
Assuntos
Miopia , Fármacos Fotossensibilizantes , Cobaias , Animais , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Raios Ultravioleta , Modelos Animais de Doenças , Reagentes de Ligações Cruzadas/farmacologia , Riboflavina/farmacologia , Miopia/prevenção & controle , Esclera , Fibroblastos , Colágeno/farmacologiaRESUMO
BACKGROUND: The design of cap thickness for small incision lenticule extraction (SMILE) plays a role in post-laser vision correction (post-LVC) corneal biomechanics. This study aimed to compare the corneal biomechanical characteristics following SMILE with different cap thicknesses of 110 µm, 120 µm, and 130 µm for myopia and myopic astigmatism correction. METHODS: Seventy-five patients (146 eyes) who underwent SMILE with designed cap thickness of 110 µm, 120 µm, and 130 µm were recruited at the Eye Center of Beijing Tongren Hospital between August 2020 and November 2021. Visual acuity, refraction, and corneal biomechanical parameters were measured preoperatively, 1 week and 1, 3, 6 months postoperatively. One-way analysis of variances (ANOVA) with Bonferroni correction or Kruskal-Wallis test was performed to compare the parameters among different groups. Repeated-measures analysis of variance with Bonferroni correction or Friedman test was applied for comparing the parameters within different follow-up times. RESULTS: Uncorrected distance visual acuity of 110-µm group was better only at 1-week and 1-month postoperatively (P = 0.012, 0.037). There were no significant differences in spherical equivalent, nor in Corvis biomechanical index-laser vision correction (CBI-LVC). All the parameters reached stability at 3-month postoperatively. Integrated radius (IR) and deformation amplitude ratio 2 mm (DA ratio 2 mm) in 120-µm and 130-µm groups were higher than 110-µm group at 1-month postoperatively (P = 0.019, 0.002). So was Ambrósio relational thickness (ARTh) at 6-month postoperatively (P = 0.011). Stiffness parameter at applanation A1 (SP-A1), stress-strain index (SSI), biomechanically corrected intraocular pressure (bIOP) and central corneal thickness (CCT) were highest in 130-µm group, followed by 120-µm group, then 110-µm group at 3-month (P<0.001, P = 0.030, P = 0.027, P = 0.008) and 6-month (P<0.001, P = 0.002, P = 0.0023, P = 0.001) postoperatively. CONCLUSIONS: The corneal stiffness following SMILE was greatest with 130-µm cap, followed by 120-µm cap, then 110-µm cap. 130-µm cap might have advantages in terms of corneal biomechanics and retreatment option. The SMILE-designed protocol should be customized in practice.
Assuntos
Astigmatismo , Cirurgia da Córnea a Laser , Miopia , Humanos , Astigmatismo/cirurgia , Córnea/cirurgia , Acuidade Visual , Refração Ocular , Miopia/cirurgia , Substância Própria/cirurgia , Cirurgia da Córnea a Laser/métodos , Lasers de Excimer/uso terapêuticoRESUMO
ABSTRACT: Riboflavin-ultraviolet A (UVA) collagen cross-linking (CXL) has been applied in clinical settings to prevent the progression of keratoconus and corneal dilatation caused by other reasons in past decades. As CXL with riboflavin-UVA can enhance the stiffness of collagen-rich tissues, this technique has been further used on sclera to investigate as a safe and effective myopia prevention treatment. Despite the riboflavin-UVA scleral CXL is still in the animal and in vitro experimental phases and the mechanism is not very clear, it is promising to control myopia development clinically. In this article, researches on the laboratory experiments of riboflavin-UVA scleral CXL on scheme exploration and mechanism were reviewed in order to provide more laboratory evidence for scleral CXL in clinical myopia prevention and control in the future.
Assuntos
Ceratocone , Miopia Degenerativa , Animais , Reagentes de Ligações Cruzadas , Humanos , Ceratocone/tratamento farmacológico , Ceratocone/prevenção & controle , Miopia Degenerativa/prevenção & controle , Fármacos Fotossensibilizantes/uso terapêutico , Riboflavina/uso terapêutico , Esclera , Raios UltravioletaRESUMO
Purpose: To assess the safety and long-term scleral biomechanical stability of rhesus eyes after blue light scleral CXL by investigating the biomechanical and microstructural changes.Methods: Seven rhesus monkeys (14 eyes) were observed in this study. All right eyes received blue light scleral CXL at the superior temporal equatorial sclera, and the left eyes served as controls. Biological ocular parameters were followed up to 1 year after scleral CXL. Stress-strain measurements of three rhesus sclera were measured, three rhesus retinas were examined histologically by H&E and TUNEL staining. And the microstructure of both the sclera and retina were observed by transmission electron microscopy at 1 year.Results: As for the retinal thickness, choroidal thickness, flow density of retinal superficial vascular networks and flash electroretinography (f-ERG) results, no significant differences were observed between the paired eyes at 1 year (P >.05). At the same time, the scleral collagen fibril distribution was much tighter, and the scleral biomechanical properties were significantly increased in the experimental eyes. However, apoptotic cells and retinal ultrastructural changes could still be found in the retina of the experimental eyes.Conclusion: This study demonstrates that blue light scleral CXL could effectively increase the scleral stiffness of the rhesus eye for at least 1 year, but ultrastructural change was still observed in the retina of scleral CXL eye. Therefore, the long-term intraocular safety of the blue light scleral CXL technique for preventing myopia progression should be investigated further.