No abstract

Our findings suggest that SMILE results in less nerve damage and faster nerve recovery than LASIK.

Corneal neovascularization (CoNV) could be treated by novel anti-angiogenic therapies, though reliable and objective imaging tools to evaluate corneal vasculature and treatment efficacy is still lacking. Optical coherence tomography angiography (OCTA) –currently designed as a retinal vascular imaging system— has been recently adapted for anterior-segment and showed good potential for successful imaging of CoNV. However, further development requires an animal model where parameters can be studied more carefully with histological comparison. Our study evaluated the OCTA in suture-induced CoNV in a rabbit model compared to indocyanine green angiography (ICGA) and slit-lamp photography (SLP). Overall vessel density measurements from OCTA showed good correlation with ICGA (0.957) and SLP (0.992). Vessels density by OCTA was higher than ICGA and SLP (mean = 20.77 ± 9.8%, 15.71 ± 6.28% and 17.55 ± 8.36%, respectively, P < 0.05). OCTA was able to depict CoNV similarly to SLP and ICGA, though it could better detect small vessels. Moreover, the depth and growth of vessels could be assessed using en-face and serial-scans. This study validated the OCTA in a rabbit model as a useful imaging tool for translational studies on CoNV. This may contribute to further studies on OCTA for anterior-segment including serial evaluation of emerging anti-angiogenic therapies.

The flap adhesion strength increased over time after treatment with both lasers. The nJ-energy pulses produced minimal wound healing reaction and apoptotic cells along the incision plane. The application of an nJ-energy laser, which can incise the cornea without inducing significant damage to cells and wound healing reaction, offers great potential at reducing scarring following incisional laser stromal surgery.

Microbial infections of the cornea are potentially devastating and can result in permanent visual loss or require vision-rescuing surgery. In recent years, there has been an increasing number of reports on nontuberculous mycobacterial infections of the cornea. Challenges to the management of nontuberculous mycobacterial keratitis include delayed laboratory detection, low index of clinical suspicion, poor drug penetration, slow response to therapy, and prolonged use of antibiotic combinations. The ability of nontuberculous mycobacteria to evade the host immune response and the ability to adhere and to form biofilms on biological and synthetic substrates contribute to the issue. Therefore, there is an urgent need for new antimicrobial compounds that can overcome these problems. In this study, we evaluated the biofilm architectures for Mycobacterium chelonae and Mycobacterium fortuitum in dynamic flow cell chamber and 8-well chamber slide models. Our results showed that mycobacterial biofilms were quite resistant to conventional antibiotics. However, DNase treatment could be used to overcome biofilm resistance. Moreover, we successfully evaluated a new antimicrobial compound (AM-228) that was effective not only for planktonic mycobacterial cells but also for biofilm treatment and was compared favorably with the most successful “fourth-generation” fluoroquinolone, gatifloxacin. Finally, a new treatment strategy emerged: a combination of DNase with an antibiotic was more effective than an antibiotic alone.

Pattern D, a lamellar ring adjacent to the cap cut, was the most optimal to be used for flap creation in cases of SMILE re-treatment.

Corneal inlays are a relatively new treatment option for presbyopia. Using biological inlays, derived from lenticules extracted from small incision lenticule extraction, may offer advantages over commercialized synthetic inlays in the aspect of biocompatibility. We conducted a non-human primate study to evaluate the safety, predictability, efficacy and tissue response after autogeneic, decellularized xenogeneic and xenogeneic lenticule implantation. The lenticule implantation effectively resulted in central corneal steepening (simulated keratometric values increased by 1.8–2.3 diopters), central hyper-prolate changes (asphericity Q values changed by −0.26 to −0.36), corneal anterior surface elevation (7.7–9.3 μm) and reasonable effective zone (1.5–1.8 times of the lenticule physical diameter), with no differences among the three groups. Slit lamp microscopy, transmission electron microscopy, confocal microscopy, histology and immunohistochemistry analyses confirmed the biocompatibility of the autogeneic and decellularized lenticules, whereas one eye in the xenogeneic group developed corneal stromal rejection during the study period. Our results showed that lenticule implantation has the potential for the management of presbyopia, and provide the basis for future clinical studies. The decellularization process may increase the potential utilization of lenticules without changing the efficacy.

Presbyopia remains a major visual impairment for patients, who have previously undergone laser refractive correction and enjoyed unaided distance vision prior to the onset of presbyopia. Corneal stromal volume restoration through small incision lenticule extraction (SMILE) lenticule re-implantation presents an opportunity for restoring the patients’ non-dominant eye to previous low myopia to achieve a monovision. In this study, we investigated the feasibility of performing LASIK after lenticule re-implantation as a method to create presbyopic monovision. A -6.00D SMILE correction was performed in 9 rabbit eyes. The lenticules were cryopreserved for 14 days and re-implanted. Five weeks later, 3 of these eyes underwent LASIK for -5.00D correction (RL group); 3 underwent LASIK flap creation, which was not lifted (RN); and no further procedures were performed on the remaining 3 eyes. These groups were compared with 3 eyes that underwent standard LASIK for a -5.00D correction (LO); 3 that underwent creation of non-lifted flap (LN); and 3 non-operated eyes. Rabbits were euthanized 1 day post-surgery. Tissue responses were analyzed by immunohistochemistry, slit lamp and in vivo confocal microscopy (IVCM). Intrastromal irregularities and elevated reflectivity levels of the excimer-ablated plane were observed on slit lamp and IVCM, respectively in the RL group. The results were comparable (P = 0.310) to IVCM findings in the LO group. RL and LO groups showed similar fibronectin expression levels, number of CD11b-positive cells (P = 0.304) and apoptotic cells (P = 0.198). There was no difference between the RN and LN groups in reflectivity levels (P = 0.627), fibronectin expression levels, CD11b-positive cells (P = 0.135) and apoptotic cells (P = 0.128). LASIK can be performed following lenticule re-implantation to create presbyopic monovision. The tissue responses elicited after performing LASIK on corneas that have undergone SMILE and subsequent lenticule re-implantation are similar to primary procedure.