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Cornea lenticule viability and structural integrity after refractive lenticule extraction (ReLEx) and cryopreservation.

ABSTRACT: PURPOSE: To assess and compare keratocyte viability and collagen structure in cornea stroma lenticules collected immediately after refractive lenticule extraction (ReLEx) and one month after cryopreservation. METHODS: The fresh and cryopreserved human stroma lenticules procured after ReLEx were processed for ultrastructural analysis of keratocytes and collagen fibrils with transmission electron microscopy (TEM), apoptotic cell detection with deoxynucleotidyl transferase-mediated nick end labeling assay (TUNEL) assay, and cultured for keratocyte-specific gene expression analysis using reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: The periphery of the lenticule had greater TUNEL-positive cells compared to the center of the lenticule in both fresh and cryopreserved groups. There was an increase in TUNEL-positive cells after cryopreservation, which was significantly higher in the center of the lenticule, but not in the periphery. TEM showed apoptotic, necrotic and viable quiescent keratocytes in fresh and cryopreserved lenticules. Collagen analysis with TEM showed a well preserved and well aligned structure in fresh and cryopreserved lenticules; without significant change in the total number of collagen fibrils but with an increased collagen fibril density (CFD) after cryopreservation. In vitro, isolated keratocytes derived from fresh and cryopreserved lenticules exhibited a typical fibroblastic phenotype. RT-PCR showed a positive gene expression for keratocan (KERA) and aldehyde dehydrogenase 3A1 (ALDH3A1) in cells isolated from fresh and cryopreserved lenticules. CONCLUSIONS: The stromal lenticules extracted from ReLEx surgery remain viable after cryopreservation. Although they showed a decrease in CFD, the collagen architecture was preserved and there was good cellular viability.

SUBMITTER: Mohamed-Noriega K

PROVIDER: S-EPMC3249438 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

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Cornea lenticule viability and structural integrity after refractive lenticule extraction (ReLEx) and cryopreservation.

Mohamed-Noriega Karim K Toh Kah-Peng KP Poh Rebekah R Balehosur Deepashree D Riau Andri A Htoon Hla M HM Peh Gary S L GS Chaurasia Shyam S SS Tan Donald T DT Mehta Jodhbir S JS

Molecular vision 20111228

<h4>Purpose</h4>To assess and compare keratocyte viability and collagen structure in cornea stroma lenticules collected immediately after refractive lenticule extraction (ReLEx) and one month after cryopreservation.<h4>Methods</h4>The fresh and cryopreserved human stroma lenticules procured after ReLEx were processed for ultrastructural analysis of keratocytes and collagen fibrils with transmission electron microscopy (TEM), apoptotic cell detection with deoxynucleotidyl transferase-mediated nic ...[more]

PMID: 22219639

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Project description:PurposeTo quantitatively evaluate outcomes after small incision lenticule extraction (SMILE) combined with allogeneic intrastromal lenticule inlay for hyperopia with astigmatism.MethodsIt's a retrospective cohort study. Twenty-four eyes of 15 patients with more than 0.75 diopters (D) of astigmatism in hyperopic eyes were enrolled in this study. The hyperopic eye with astigmatism was first treated with SMILE to correct astigmatism; then a lenticule was extracted from a donor myopic eye and subsequently implanted into the hyperopic eye with astigmatism. Patients were examined preoperatively and 1 day, 1 week, 1,3 months and 1 year after surgery. The main outcome measures were the uncorrected and corrected distance visual acuity (UDVA and CDVA), uncorrected near visual acuity (UNVA), spherical equivalent (SE), corneal topography, anterior segment optical coherence topography (OCT) and ocular response analyzer (ORA) parameters: corneal hysteresis (CH) and corneal resistance factor (CRF). Repeated-measures analyses of variance (ANOVA) and post hoc tests were used to analyze data of different follow-up visits.ResultsThe mean preoperative cylinder was 1.95±1.04(D). The UDVA (from 0.37±0.23 to 0.09±0.09), UNVA (from 0.49±0.21 to 0.08±0.06), SE (from +7.42±3.12 to -0.75±0.79) and astigmatism (+1.95±1.04 to -0.65±0.63) postoperatively were obviously better than those before surgery. Five eyes (26.3%) gained one line of CDVA, and 3 eyes (15.8%) gained two lines of CDVA one year after surgery compared with preoperative levels. The average corneal curvature was changed from (43.19±4.37) D to (49.19±3.87) D one year after surgery. The anterior segment OCT images of corneas with lenticule inlays at each follow-up visit showed that the implanted lenticule was shaped like a crescent in the corneal stroma. The CH and CRF didn't change significantly after surgery (p = 0.189 and p = 0.107respectively).ConclusionsSMILE combined with intrastromal lenticule inlay can be used to correct high hyperopia with astigmatism with good safety, efficacy and reproducibility.

Project description:BackgroundSmall-incision lenticule extraction (SMILE) is a surgical procedure for the refractive correction of myopia and astigmatism, which has been reported as safe and effective. However, over- and under-correction still occur after SMILE. The necessity of nomograms is emphasized to achieve optimal refractive results. Ophthalmologists diagnose nomograms by analyzing the preoperative refractive data with their individual knowledge which they accumulate over years of experience. Our aim was to predict the nomograms of sphere, cylinder, and astigmatism axis for SMILE accurately by applying machine learning algorithm.MethodsWe retrospectively analyzed the data of 3,034 eyes composed of four categorical features and 28 numerical features selected from 46 features. The multiple linear regression, decision tree, AdaBoost, XGBoost, and multi-layer perceptron were employed in developing the nomogram models for sphere, cylinder, and astigmatism axis. The scores of the root-mean-square error (RMSE) and accuracy were evaluated and compared. Subsequently, the feature importance of the best models was calculated.ResultsAdaBoost achieved the highest performance with RMSE of 0.1378, 0.1166, and 5.17 for the sphere, cylinder, and astigmatism axis, respectively. The accuracies of which error below 0.25 D for the sphere and cylinder nomograms and 25° for the astigmatism axis nomograms were 0.969, 0.976, and 0.994, respectively. The feature with the highest importance was preoperative manifest refraction for all the cases of nomograms. For the sphere and cylinder nomograms, the following highly important feature was the surgeon.ConclusionsAmong the diverse machine learning algorithms, AdaBoost exhibited the highest performance in the prediction of the sphere, cylinder, and astigmatism axis nomograms for SMILE. The study proved the feasibility of applying artificial intelligence (AI) to nomograms for SMILE. Also, it may enhance the quality of the surgical result of SMILE by providing assistance in nomograms and preventing the misdiagnosis in nomograms.

Dataset Information

Cornea lenticule viability and structural integrity after refractive lenticule extraction (ReLEx) and cryopreservation.

Publications

Cornea lenticule viability and structural integrity after refractive lenticule extraction (ReLEx) and cryopreservation.

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