Metabolomic profiling of ocular tissues in rabbit myopia: Uncovering differential metabolites and pathways.

To investigate the metabolic difference among tissue layers of the rabbits' eye during the development of myopia using metabolomic techniques and explore any metabolic links or cascades within the ocular wall. Ultra Performance Liquid Chromatography - Mass Spectrometry (UPLC-MS) was utilized for untargeted metabolite screening (UMS) to identify the significant differential metabolites produced between myopia (MY) and control (CT) (horizontal). Subsequently, we compared those key metabolites among tissues (Sclera, Choroid, Retina) of MY for distribution and variation (longitudinal). A total of 6285 metabolites were detected in the three tissues. The differential metabolites were screened and the metabolic pathways of these metabolites in each myopic tissue were labeled, including tryptophan and its metabolites, pyruvate, taurine, caffeine metabolites, as well as neurotransmitters like glutamate and dopamine. Our study suggests that multiple metabolic pathways or different metabolites under the same pathway, might act on different parts of the eyeball and contribute to the occurrence and development of myopia by affecting the energy supply to the ocular tissues, preventing antioxidant stress, affecting scleral collagen synthesis, and regulating various neurotransmitters mutually.

Four-year follow-up of corneal aberrations and visual functions of myopic patients after laser in situ keratomileusis.

OBJECTIVE: To report on 4-year follow-up of corneal higher-order aberrations and daily visual functions of myopic patients after laser in situ keratomileusis (LASIK). METHODS: One hundred thirty four eyes of 67 patients who underwent LASIK guided by aspherical ablation were included in this study. The vision, corneal spherical aberration (SphA) and Coma were recorded before LASIK and at 6 month and 4 year after LASIK. The evaluation of the questionnaire about daily visual functions was performed by the same physician after LASIK. RESULTS: No eye decreased the BCVA during 4 year follow-up. The effect index and safety index were 1.08±0.16, 1.11±0.17 and 1.12±0.16, 1.13±0.14 respectively at 6 month and 4 year post-LASIK. After LASIK the corneal SphA and Coma were significantly increased, however the difference between 6 month and 4 year post-LASIK was no statistical significance. Most patients (94.3%-92.4%) felt satisfaction or high satisfaction about the ability to perform each daily visual function after LASIK. Meanwhile there was still about 7.4%-9.2% patients who complained that they could not drive at night. Further analysis showed that the score of driving at night was negative correlation with corneal SphA (r=-0.645, p=0.040; r=-0.688, p=0.040 at 6 month and 4 year post-LASIK respectively). CONCLUSIONS: Our four-year follow-up outcomes indicated that the myopic patients after LASIK had the long-term stable corneal aberration and satisfaction of daily visual functions.

Central toxic keratopathy after small incision lenticule extraction surgery:A case report.

PURPOSE: To report a rare case of central toxic keratopathy after small incision lenticule extraction surgery (SMILE). CASE REPORT: A 38-year-old female presented with visual loss 10 days after undergoing SMILE. Subsequently, transparent band keratopathy was protruded in the left cornea and corneal cap opacity was increased, which was accompanied by hyperopic shift and corneal thinning. The patient's condition rapidly improved with the administration of prednisolone acetate and autologous serum, with significant resolution of the transparent band keratopathy within 5 weeks of treatment initiation and subsequent complete visual recovery. CONCLUSIONS: Central toxic keratopathy is a severe complication after undergoing SMILE, which might be effectively treated using with steroids and autologous serum.

Effects of Corneal Stromal Lens Collagen Cross-Linking Regraft on Corneal Biomechanics.

Background: Corneal collagen cross-linking (CXL) therapy, a method that uses a combination of riboflavin and ultraviolet-A light (UVA), can promote the formation of covalent cross-linking of amino acid residues of corneal collagen and enhance the hardness of the cornea. In this study, we explored the effects of corneal stromal lens collagen cross-linking regraft on corneal biomechanics. Methods: A total of 15 New Zealand white rabbits were divided into 3 groups: normal control group (group A), SMILE + uncross-linked lens implantation group (Group B), and SMILE + cross-linking lens implantation group (group C). The design parameters of SMILE surgery were as follows: the corneal cap was 120 um thick, the lens diameter was 6.5 mm, and the diopter was -6.0D. Riboflavin and ultraviolet-A (UVA) were used as corneal stromal lens CXL, which was implanted into the allogeneic rabbit corneal stromal bag 24 hours after the operation. Postoperative corneal thickness (CCT), refraction, AS-OCT, and corneal biomechanics were performed before and then at 1 and 3 months after the operation. Results: All corneas appeared transparent and smooth 3 months after surgery. The corneal thicknesses of both group B and group C were lower than those before the operation. The corrected refraction of group B and group C after lens implantation was also lower than the expected corrected power; there was no significant difference between the two groups (P > 0.05). AS-OCT results showed an uneven surface and thickness of the corneal stromal lens in two eyes of group B. Moreover, corneal elastic deformation increased with intraocular pressure in each group; displacement from large to small was group B > group C and > group A. The creep from large to small was group B > group C > group A. The fiberboard layers of groups B and C were disordered, and there were a few autophagosomes in the fibroblasts of group B by transmission electron microscopy (TEM). Conclusions: Allograft graft of corneal stromal lens collagen cross-linked can significantly increase the biomechanical properties of the cornea.

Effects of V4c-ICL Implantation on Myopic Patients' Vision-Related Daily Activities.

The new type implantable Collamer lens with a central hole (V4c-ICL) is widely used to treat myopia. However, halos occur in some patients after surgery. The aim is to evaluate the effect of V4c-ICL implantation on vision-related daily activities. This retrospective study included 42 patients. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), intraocular pressure (IOP), endothelial cell density (ECD), and vault were recorded and vision-related daily activities were evaluated at 3 months after operation. The average spherical equivalent was -0.12 ± 0.33 D at 3 months after operation. UCVA equal to or better than preoperative BCVA occurred in 98% of eyes. The average BCVA at 3 months after operation was -0.03 ± 0.07 LogMAR, which was significantly better than preoperative BCVA (0.08 ± 0.10 LogMAR) (P = 0.029). Apart from one patient (2.4%) who had difficulty reading computer screens, all patients had satisfactory or very satisfactory results. During the early postoperation, halos occurred in 23 patients (54.8%). However there were no significant differences in the scores of visual functions between patients with and without halos (P > 0.05). Patients were very satisfied with their vision-related daily activities at 3 months after operation. The central hole of V4c-ICL does not affect patients' vision-related daily activities.