1
|
Liu C, Lin MTY, Lee IXY, Mehta JS, Liu YC. Impact of corrected refractive power on the corneal denervation and ocular surface in small-incision lenticule extraction and LASIK. J Cataract Refract Surg 2023; 49:1106-1113. [PMID: 37867284 PMCID: PMC10583913 DOI: 10.1097/j.jcrs.0000000000001278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 10/24/2023]
Abstract
PURPOSE To evaluate the impact of corrected refractive power on the corneal denervation and ocular surface in small-incision lenticule extraction (SMILE) and laser in situ keratomileusis (LASIK). SETTING Singapore National Eye Center, Singapore. DESIGN Prospective study. METHODS 88 eyes undergoing SMILE or LASIK were divided into low-moderate (manifest refractive spherical equivalent [MRSE] <-6.0 diopters [D]) and high myopic (MRSE ≥-6.0 D) groups. In vivo confocal microscopy and clinical assessments were performed preoperatively and at 1 month, 3 months, 6 months, and 12 months postoperatively. RESULTS In SMILE, high myopic treatment presented with significantly greater reduction in the corneal nerve fiber area (CNFA) and nerve fiber fractal dimension (CFracDim) compared with low-moderate myopic treatment (both P < .05). There was a significant and negative correlation between the corrected MRSE and the reduction in corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length, CNFA, and CFracDim after SMILE (r = -0.38 to -0.66, all P < .05). In LASIK, a significant correlation between the MRSE and the changes in CNBD, corneal nerve fiber total branch density, CNFA (r = -0.37 to -0.41), and corneal nerve fiber width (r = 0.43) was observed (all P < .05). Compared with SMILE, LASIK had greater reduction in CNBD and CNFA for every diopter increase in the corrected MRSE. High myopic SMILE, compared with low-moderate myopic SMILE, resulted in significantly lower tear break-up time at 1 and 6 months (both P < .05). The changes in CNFA and CFracDim were significantly associated with Schirmer test values (both P < .001). CONCLUSIONS Postoperative corneal denervation was related to corrected refractive power in both SMILE and LASIK. With the same refractive correction, LASIK led to more prominent corneal denervation.
Collapse
Affiliation(s)
- Chang Liu
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| | - Molly Tzu-Yu Lin
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| | - Isabelle Xin Yu Lee
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| | - Jodhbir S. Mehta
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| | - Yu-Chi Liu
- From the Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore (C. Liu, Lin, Lee, Mehta, Y.-C. Liu); Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore (C. Liu, Mehta); Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore (Mehta, Y.-C. Liu); Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore (Mehta, Y.-C. Liu); Department of Ophthalmology, National Taiwan University, Taiwan (Y.-C. Liu)
| |
Collapse
|
2
|
Hu X, Wei R, Liu C, Wang Y, Yang D, Sun L, Xia F, Liu S, Li M, Zhou X. Recent advances in small incision lenticule extraction (SMILE)-derived refractive lenticule preservation and clinical reuse. ENGINEERED REGENERATION 2023. [DOI: 10.1016/j.engreg.2023.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
|
3
|
Santra M, Liu YC, Jhanji V, Yam GHF. Human SMILE-Derived Stromal Lenticule Scaffold for Regenerative Therapy: Review and Perspectives. Int J Mol Sci 2022; 23:ijms23147967. [PMID: 35887309 PMCID: PMC9315730 DOI: 10.3390/ijms23147967] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/10/2022] [Accepted: 07/18/2022] [Indexed: 12/13/2022] Open
Abstract
A transparent cornea is paramount for vision. Corneal opacity is one of the leading causes of blindness. Although conventional corneal transplantation has been successful in recovering patients’ vision, the outcomes are challenged by a global lack of donor tissue availability. Bioengineered corneal tissues are gaining momentum as a new source for corneal wound healing and scar management. Extracellular matrix (ECM)-scaffold-based engineering offers a new perspective on corneal regenerative medicine. Ultrathin stromal laminar tissues obtained from lenticule-based refractive correction procedures, such as SMall Incision Lenticule Extraction (SMILE), are an accessible and novel source of collagen-rich ECM scaffolds with high mechanical strength, biocompatibility, and transparency. After customization (including decellularization), these lenticules can serve as an acellular scaffold niche to repopulate cells, including stromal keratocytes and stem cells, with functional phenotypes. The intrastromal transplantation of these cell/tissue composites can regenerate native-like corneal stromal tissue and restore corneal transparency. This review highlights the current status of ECM-scaffold-based engineering with cells, along with the development of drug and growth factor delivery systems, and elucidates the potential uses of stromal lenticule scaffolds in regenerative therapeutics.
Collapse
Affiliation(s)
- Mithun Santra
- Corneal Regeneration Laboratory, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (M.S.); (V.J.)
| | - Yu-Chi Liu
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore;
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Vishal Jhanji
- Corneal Regeneration Laboratory, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (M.S.); (V.J.)
| | - Gary Hin-Fai Yam
- Corneal Regeneration Laboratory, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (M.S.); (V.J.)
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore;
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Correspondence:
| |
Collapse
|
5
|
Yam GHF, Bandeira F, Liu YC, Devarajan K, Yusoff NZBM, Htoon HM, Mehta JS. Effect of corneal stromal lenticule customization on neurite distribution and excitatory property. J Adv Res 2021; 38:275-284. [PMID: 35572401 PMCID: PMC9091752 DOI: 10.1016/j.jare.2021.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 09/05/2021] [Accepted: 09/14/2021] [Indexed: 11/29/2022] Open
Abstract
Refractive SMILE-derived stromal lenticules are useful in various tissue-engineering approach for therapeutics, of which they are required to be customized before implantation. Excimer laser-mediated reshaping, riboflavin-UVA-induced collagen crosslinking and chemical decellularization significantly removed lenticule neurites, but the residual neurites retained excitatory response. Reinnervation occurred in the decellularized lenticules, indicating a potential of nerve regeneration. Stromal lenticules, as a unique collagen-rich biomaterial with high transparency, refractivity and mechanically robust, together with the ability of neurite regeneration, could hold a potential for various ophthalmic applications.
Introduction Refractive stromal lenticules from Small Incision Lenticule Extraction (SMILE), though usually discarded, hold a potential for various ophthalmic applications, including refractive correction, stromal volume expansion, and biomechanical strengthening of the cornea. Objectives To investigate the effect of lenticule customization on lenticule neurite length profile and the excitatory response (calcium signaling) and the potential of reinnervation. Methods Human and porcine stromal lenticules were treated by (1) excimer laser reshaping, (2) ultraviolet A-riboflavin crosslinking (CXL), and (3) decellularization by sodium dodecyl sulfate (SDS), respectively. The overall neurite scaffold immuno-positive to TuJ1 (neuron-specific class III β-tubulin) expression and population of active neurite fragments with calcium response revealed by L-glutamate-induced Fluo-4-acetoxymethyl ester reaction were captured by wide-field laser-scanning confocal microscopy, followed by z-stack image construction. The NeuronJ plugin was used to measure neurite lengths for TuJ1 (NL-TuJ1) and calcium signal (NL-Ca). Reinnervation of lenticules was examined by the ex vivo grafting of chick dorsal root ganglia (DRG) to the decellularized human lenticules. Differences between groups and controls were analyzed with ANOVA and Mann-Whitney U test. Results The customization methods significantly eliminated neurites inside the lenticules. NL-TuJ1 was significantly reduced by 84% after excimer laser reshaping, 54% after CXL, and 96% after decellularization. The neurite remnants from reshaping and CXL exhibited calcium signaling, indicative of residual excitatory response. Re-innervation occurred in the decellularized lenticules upon stimulation of the grafted chick embryo DRG with nerve growth factor (NGF 2.5S). Conclusion All of the lenticule customization procedures reduced lenticule neurites, but the residual neurites still showed excitatory potential. Even though these neurite remnants seemed minimal, they could be advantageous to reinnervation with axon growth and guidance after lenticule reimplantation for refractive and volume restoration of the cornea.
Collapse
|
6
|
Liu YC, Jung ASJ, Chin JY, Yang LWY, Mehta JS. Cross-sectional Study on Corneal Denervation in Contralateral Eyes Following SMILE Versus LASIK. J Refract Surg 2021; 36:653-660. [PMID: 33034357 DOI: 10.3928/1081597x-20200730-01] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/21/2020] [Indexed: 01/16/2023]
Abstract
PURPOSE To compare long-term corneal nerve status following small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK). METHODS Twenty-four patients were randomized to receive SMILE in one eye and LASIK in the other eye. In vivo confocal microscopy examination and dry eye assessments were performed at a mean of 4.1 years postoperatively. The patients were further divided into two groups based on the mean assessment time: 2.7 years postoperatively (2.7 years group) and 5.5 years postoperatively (5.5 years group). Another 6 age-matched normal patients were recruited. RESULTS At 4.1 years, LASIK eyes had significantly less corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and corneal total branch density and significantly more nerves with beading than SMILE eyes. The CNFD, CNBD, CNFL, and number of nerves with sprouting were significantly higher in the 5.5 years group than in the 2.7 years group, in both types of surgery, suggesting persistent nerve regeneration. The CNBD and CNFD in the 5.5 years group, regardless of surgical types, were significantly lower than those in the control group, indicating the nerve status had not recovered to normal ranges even at 5.5 years. High myopic treatment resulted in significantly reduced CNFD with LASIK but not with SMILE. There were no significant differences in the dry eye parameters between the two procedures at 4.1 years postoperatively. CONCLUSIONS The impact on corneal nerves following refractive surgery is long-lasting. SMILE had better nerve preservation and regeneration than LASIK, but neither procedure had recovered nerve status to normal levels even at 5.5 years. [J Refract Surg. 2020;36(10):653-660.].
Collapse
|
7
|
Chin JY, Lin MTY, Lee IXY, Mehta JS, Liu YC. Tear Neuromediator and Corneal Denervation Following SMILE. J Refract Surg 2021; 37:516-523. [PMID: 34388069 DOI: 10.3928/1081597x-20210423-01] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE To investigate the changes in tear neuromediators and corneal subbasal nerve plexus following small incision lenticule extraction (SMILE) and to study its association with different refractive power of corrections. METHODS Thirty patients were included for tear neuromediator analysis (40 eyes) and corneal nerve analysis using in vivo confocal microscopy scans (20 eyes). Tear samples were collected preoperatively and 1 week and 1, 3, 6, and 12 months postoperatively and analyzed for the substance P, calcitonin gene-related peptide (CGRP), and nerve growth factor (NGF) concentrations using the enzyme-linked immunosor-bent assay (ELISA). RESULTS Corneal nerve fiber density (CNFD), corneal nerve fiber length (CNFL), and corneal nerve branch density (CNBD) decreased significantly postoperatively, then gradually increased from 3 months onward, but did not recover to the baseline levels at 12 months. Tear substance P and CGRP levels remained stable over 12 months. Tear NGF levels demonstrated a small peak at 1 week before decreasing significantly compared to preoperative levels at 6 months (P = .03) and 12 months (P = .007). The 1-month reduction in CNFL, tear substance P, and CGRP concentrations were significantly correlated with the corrected spherical equivalent (SE) (r = 0.71 for CNFL; r = -0.33 to -0.52 at different time points for substance P and CGRP, respectively, all P < .05). Compared to the low to moderate myopia group, the high myopia group (corrected SE greater than -6.00 diopters) had a significantly greater decrease in CNFD, significantly higher tear substance P concentrations at 1 week, 1 month, and 6 months, and significantly higher tear CGRP concentrations at 1 and 6 months. CONCLUSIONS These results provide new insight into the neurobiological responses and their potential implications in corneal nerve damage and recovery after SMILE. High myopia treatment was associated with greater corneal denervation and neuroinflammation. [J Refract Surg. 2021;37(8):516-523.].
Collapse
|