The majority of stem cell therapies for corneal repair are based upon the use of progenitor cells isolated from corneal tissue, but a growing body of literature suggests a role for mesenchymal stromal cells (MSC) isolated from noncorneal tissues. While the mechanism of MSC action seems likely to involve their immuno-modulatory properties, claims have emerged of MSC transdifferentiation into corneal cells. Substantial differences in methodology and experimental outcomes, however, have prompted us to perform a systematic review of the published data. Key questions used in our analysis included: the choice of markers used to assess corneal cell phenotype, the techniques used to detect these markers, adequate reporting of controls, and tracking of MSC when studied in vivo. Our search of the literature revealed 28 papers published since 2006, with half appearing since 2012. MSC cultures established from bone marrow and adipose tissue have been best studied (22 papers). Critically, only 11 studies used appropriate markers of corneal cell phenotype, along with necessary controls. Ten out of these eleven papers, however, contained positive evidence of corneal cell marker expression by MSC. The clearest evidence is observed with respect to expression of markers for corneal stromal cells by MSC. In comparison, the evidence for MSC conversion into either corneal epithelial cells or corneal endothelial cells is often inconsistent or inconclusive. Our analysis clarifies this emerging body of literature and provides guidance for future studies of MSC differentiation within the cornea as well as other tissues. STEM CELLS 2015;33:785-791

Introduction Surgically induced astigmatism is an unwanted variable that can lead to poorer visual and refractive outcomes in patients undergoing vitrectomy even when a technically precise procedure has been performed. This study assesses the difference in surgically induced astigmatism (SIA) between the traditional 20-gauge vitrectomy and the newer 25-gauge sutureless technique by comparing pre-and post-procedure keratometry readings. Method The study is a retrospective consecutive case series of vitrectomies performed by a single surgeon. There were a total of 47 patients, eight with bilateral procedures, 24 who underwent the 20 gauge, and 31 who had the 25-gauge procedure. Patients were excluded for corneal altering pathology or scleral buckling procedures. Vector analysis of pre-and post-vitrectomy readings was performed using Alpin's method, facilitated by the ASSORT program version 4.1. Results Mean time at which post-operative keratometry readings were taken was 3.9 months (1-36).

Whilst no published reports link tamoxifen and macular holes, this may be due to the low incidence of the condition. Our study demonstrates a strong link between tamoxifen use and macular holes. Patients being commenced on tamoxifen should be advised of possible ocular complications and receive prompt ophthalmic review if symptoms develop.

This surveillance study is the first worldwide to document the incidence of limbal stem cell deficiency; however, because of study design limitations, it is likely to have been under-reported. It provides novel data on the demographics, clinical conditions and management of patients with limbal stem cell deficiency as reported by treating ophthalmologists.

These findings indicate that irradiation of tarsal collagen leading to tissue stiffening could be a safe procedure for treating lax eyelid conditions in human patients.