Representative SEM micrographs showing the remaining stroma after the lenitcule extraction by different instruments in the non-optimizing laser setting.

<p>The remaining stroma after the lenticule extraction remained intact, without damage caused by the instruments. Magnification 200x, scale bar: 100 µm.</p

New Instruments for Lenticule Extraction in Small Incision Lenticule Extraction (SMILE)

<div><p>Small incision lenticule extraction (SMILE) is an alternative to Laser-Assisted in situ Keratomileusis (LASIK) for correction of myopia. In cases where surgeons inadvertently dissect the posterior surface first, identification of the anterior surface and subsequent removal become difficult since the anterior surface of the lenticule is compacted against the anterior stromal surface. This may result in incomplete lenticule removal, and a remnant of intrastromal lenticule in SMILE may lead to visual sequelae. In order to aid surgeons in lenticule removal, we have designed and developed 5 novel SMILE lenticule strippers to locate and extract the lenticules more easily. The aim of this study was to investigate and compare the efficacy and quality of these lenticule strippers in assisting SMILE. Thirty porcine eyes were used. The ease of extraction and removal of the lenticule with different strippers was graded by an experienced SMILE surgeon, the extracted lenticule circularity was evaluated by calculating the lenticule circularity, and the intactness of the extracted lenticule edge was assessed using scanning electron microscopy. We found these novel strippers can be of great help to improve the safety and quality of SMILE surgery, particularly in those cases of difficult lenticule extraction.</p></div

The qualitative assessments of the ease of lenticule extraction with different instruments.

<p>The qualitative assessments of the ease of lenticule extraction with different instruments.</p

Representative SEM micrographs of the lenitcules extracted by different instruments (center: 75x, scale bar: 200 µm; left corner: 300x, scale bar: 100 µm).

<p>(A) The lenticules extracted with the optimized laser setting. (B) The lenticules extracted with non-optimized laser setting. The lenticules extracted by No. 2 or No.3 lenticule strippers had regional torn or distorted edge, with edge tags on. On the contrary, the lenticules extracted by No. 4 or No. 5 lenticule strippers maintained the edge more intact with less edge tags on, either in the optimized or non-optimized laser setting. Magnification: 75x, scale bar: 200 µm.</p

The pictures of the extracted lenticules and the mean lenticule circularity for different instruments.

<p>(A) Different designed SMILE lenticule strippers. (B) The corresponding extracted lenticules and the mean lenticule circularity for different instruments in the optimized laser setting. A circularity value approaching 1.0 indicates a circular profile. There was no significant difference in the lenticule circularity between any two of the instruments. (C) The corresponding extracted lenticules and the mean lenticule circularity for different instruments in the non-optimized laser setting, simulating difficult extracting conditions. Torn and distorted edges were observed in the lenticules extracted by No. 2 and No. 3 lenticule strippers, whereas the lenticules extracted by No. 4 or No.5 lenticule strippers maintained almost round shape with smoother and more even edge. The lenticule circularity for No. 2 or No. 3 lenticule strippers were significantly lower than that for No. 4 and No. 5 lenticule strippers.</p

Subjective grading of extraction/removal of lenticules.

<p>Subjective grading of extraction/removal of lenticules.</p

Hevin Plays a Pivotal Role in Corneal Wound Healing

<div><p>Background</p><p>Hevin is a matricellular protein involved in tissue repair and remodeling via interaction with the surrounding extracellular matrix (ECM) proteins. In this study, we examined the functional role of hevin using a corneal stromal wound healing model achieved by an excimer laser-induced irregular phototherapeutic keratectomy (IrrPTK) in hevin-null (hevin^-/-) mice. We also investigated the effects of exogenous supplementation of recombinant human hevin (rhHevin) to rescue the stromal cellular components damaged by the excimer laser.</p> <p>Methodology/Principal Findings</p><p>Wild type (WT) and <i>hevin</i>^<i>-/-</i> mice were divided into three groups at 4 time points- 1, 2, 3 and 4 weeks. Group I served as naïve without any treatment. Group II received epithelial debridement and underwent IrrPTK using excimer laser. Group III received topical application of rhHevin after IrrPTK surgery for 3 days. Eyes were analyzed for corneal haze and matrix remodeling components using slit lamp biomicroscopy, in vivo confocal microscopy, light microscopy (LM), transmission electron microscopy (TEM), immunohistochemistry (IHC) and western blotting (WB). IHC showed upregulation of hevin in IrrPTK-injured WT mice. <i>Hevin</i>^<i>-/-</i> mice developed corneal haze as early as 1-2 weeks post IrrPTK-treatment compared to the WT group, which peaked at 3-4 weeks. They also exhibited accumulation of inflammatory cells, fibrotic components of ECM proteins and vascularized corneas as seen by IHC and WB. LM and TEM showed activated keratocytes (myofibroblasts), inflammatory debris and vascular tissues in the stroma. Exogenous application of rhHevin for 3 days reinstated inflammatory index of the corneal stroma similar to WT mice. </p> <p>Conclusions/Significance</p><p>Hevin is transiently expressed in the IrrPTK-injured corneas and loss of hevin predisposes them to aberrant wound healing. <i>Hevin</i>^<i>-/-</i> mice develop early corneal haze characterized by severe chronic inflammation and stromal fibrosis that can be rescued with exogenous administration of rhHevin. Thus, hevin plays a pivotal role in the corneal wound healing.</p> </div

Donor information.

<p>COD: cause of death. Donor age ranged from 10 year-old to 42 year old with a median age of 26 year old. Days taken from death of donor to the initiation of corneal endothelial cell culture ranged from 3 days to 13 days with a median of 8 days. Experiment A: morphological assessment/growth profile - P0 to P1; Experiment B: morphological assessment/growth profile - P1 onwards; Experiment C: Cell adherence analysis – xCelligence; Experiment D: Cell proliferation – Click-iT EdU; Experiment E: Immunofluorescence staining.</p

Supplemented media used in the culture of human corneal endothelial cells.

<p>Supplemented media used in the culture of human corneal endothelial cells.</p

Schematic diagram depicting processes involved in the isolation and propagation of hCECs.

<p><b>A</b>: All research-grade corneas used in this study were procured from Lions Eye Institute for Transplant and Research Inc. (Tampa, FL). Research corneas were preserved and transported in Optisol-GS, and were used within 10 days from preservation. <b>B</b>: Once received, corneas were washed thrice in an antibiotic, antimycotic wash solution. The DM-CE was peeled and the hCECs were isolated and plated into passage 0 cultures within a day. <b>C</b>: Isolated hCECs were seeded and propagated in the 4 culture conditions for up to 4 weeks. <b>D</b> and <b>E</b>: Confluent cells at each time point were trypsinized using TrypLE Express and seeded at a matched density of 5,000 cells/cm².</p