Limbal BCAM expression identifies a proliferative progenitor population capable of holoclone formation and corneal differentiation.

The corneal epithelium is renowned for high regenerative potential, which is dependent on the coordinated function of its diverse progenitor subpopulations. However, the molecular pathways governing corneal epithelial progenitor differentiation are incompletely understood. Here, we identify a highly proliferative limbal epithelial progenitor subpopulation characterized by expression of basal cell adhesion molecule (BCAM) that is capable of holocone formation and corneal epithelial sheet generation. BCAM-positive cells can be found among ABCB5-positive limbal stem cells (LSCs) as well as among ABCB5-negative limbal epithelial cell populations. Mechanistically, we show that BCAM is functionally required for cellular migration and differentiation and that its expression is regulated by the transcription factor p63. In aggregate, our study identifies limbal BCAM expression as a marker of highly proliferative corneal epithelial progenitor cells and defines the role of BCAM as a critical molecular mediator of corneal epithelial differentiation.

Two-hole assisted phaco-chop technique: a more efficient method for safe nucleofractis vertical chopping.

PURPOSE: To evaluate the use of the two-hole technique in augmenting the efficiency of surgeons-in-training when performing the phaco-chop technique. We hypothesized that drilling two holes in opposite angles to each other adjacent to the capsulorhexis would mimic a new lens equator. The phaco-tip and the chopper can be inserted into these holes at appropriate depths and may sandwich and fracture the lens more easily than conventional methods. METHODS: The two-hole technique described above was performed by three first-year surgeons before they performed the standard phaco-chop technique. We collected data of their first 8 cases and analyzed a total of 64 cases: 16, divide-and-conquer; 24, two-hole method; 24, phaco-chop. The main outcome measures included the cumulative dissipated energy (CDE) and case ultrasound time (UST) with different phacoemulsification techniques. RESULTS: The young practicing surgeons eventually performed the standard phaco-chop more safely after repeated practice using the two-hole method. The drilling of holes enabled deep and effortless impaling of the nucleus. Although there was no significant difference in the CDE among the techniques, there was a significant difference in the UST (P < 0.05). CONCLUSION: The two-hole method enabled surgeons-in-training to acquire standard phaco-chop skills more efficiently. However, further studies with higher statistical power will be needed to validate these findings. Additionally, a variation of this technique, the four-hole method, is applicable even for experienced surgeons in cases of a hardened nucleus.

Factory-Made Elastic Silicone Sheet as an Alternative for the Posterior Capsule of the Lens During Phacoemulsification for Dislocated/Subluxated Lenses.

BACKGROUND: We previously reported a novel technique using an elastic silicone bowl, which was handmade from a phaco test chamber, to salvage dislocated lenses and perform phacoemulsification and aspiration (PEA) on the bowl. However, creating the bowl was challenging. METHODS: A factory-made elastic silicone sheet (ESS), a ready-to-use alternative for the posterior capsule of the lens, was prepared. We used this sheet to salvage and support the dislocated/subluxated lenses in 11 eyes of nine patients. RESULTS: We could use a sheet immediately after we opened the package. In all the cases, we could insert a sheet beneath the lens and PEA performed at the center of the operative field. There was only one incident where the lens could not be placed onto the disc at the first attempt, but the lens was eventually salvaged. There was no risk of rupture during PEA, and the ESS could be removed completely without any complications. CONCLUSION: The factory-made ESS described here can be used for salvaging dislocated/subluxated lenses and safely performing PEA.

Comparison of ocular surface squamous neoplasia and pterygium using anterior segment optical coherence tomography angiography.

PURPOSE: To compare ocular surface squamous neoplasia (OSSN) and pterygium using anterior segment optical coherence tomography angiography (AS-OCTA). OBSERVATIONS: Flow patterns of conjunctival vessels in patients with OSSN and pterygium were investigated using AS-OCTA. In case 1, slit-lamp examination of a 72-year-old woman revealed an elevated lesion with increased permeability of fluorescein in the inferior nasal conjunctiva of her left eye. AS-OCTA showed markedly meandering large blood vessels in both the superficial and deep layers. Histopathological evaluation of the conjunctival biopsy indicated conjunctival intraepithelial neoplasia. Case 2 was that of a 79-year-old man with a history of three conjunctival tumor excisions. Slit-lamp examination showed an elevated lesion with hyperpermeability of fluorescein in the nasal conjunctiva of his left eye. AS-OCTA revealed increased meandering vasculature in both the superficial and deep layers. Histopathological investigation concluded that the diagnosis was squamous cell carcinoma. Case 3 involved a 61-year-old man with a pterygium. Slit-lamp examination showed typical findings of an elevated nasal lesion accompanied by a head that appeared triangular with a blunt apex. AS-OCTA revealed increased straight vasculature in the superficial layer and an avascular area in the deep layer of the pterygium head. CONCLUSIONS AND IMPORTANCE: AS-OCTA revealed abnormal "zigzag vessel patterns" in both the superficial and deep layers denoting meandering vessels in the patients with OSSN. In the patient with the pterygium, it showed "straight vessel patterns" signifying unbending stretched vessels in the superficial layer and an avascular zone in the deep layer of the pterygium head. These findings may be useful for the differential diagnosis of OSSN and pterygium.

Anterior Segment Optical Coherence Tomography Angiography in Patients Following Cultivated Oral Mucosal Epithelial Transplantation.

PURPOSE: To analyze corneal neovascularization using anterior segment optical coherence tomography angiography (AS-OCTA) in patients following cultivated oral mucosal epithelial sheet transplantation (COMET). DESIGN: Observational case series. METHODS: Nine eyes in 7 patients were analyzed. Four images of corneal quadrant were obtained by AS-OCTA from each patient during follow-up post-COMET in the Department of Ophthalmology at Osaka University Hospital. The depth of corneal neovascularization was evaluated using en face and B-scan images. Each quadrant image was classified as 1 of the following 5 types: stromal, predominantly stromal, epithelial, predominantly epithelial, or avascular. The image quality of slit-lamp photography and AS-OCTA was graded from 0 to 4. Manually segmented images of the epithelial and stromal vessels were obtained. MAIN OUTCOME MEASURES: Depth and image quality of corneal neovascularization following COMET. RESULTS: Six patients were male and 1 was female. The mean patient age was 61.3 ± 19.1 years. Thirty-six quadrant images were obtained, of which 4 (11.1%) were stromal, 16 (44.4%) were predominantly stromal, 3 (8.3%) were epithelial, 11 (30.6%) were predominantly epithelial, and 2 (5.6%) were avascular. The image quality obtained by AS-OCTA was significantly better than that obtained by slit-lamp photography (2.38 ± 0.94 vs 2.03 ± 0.90; P = .021). Segmentation images clearly demonstrated both epithelial and stromal vasculatures individually. CONCLUSIONS: AS-OCTA is useful for evaluation of depth of corneal neovascularization and has the potential to distinguish between conjunctivalization and stromal neovascularization following COMET. Findings on AS-OCTA could contribute to clinical decision making, given that retreatment is required for conjunctivalization after COMET.