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Purpose: To determine the incidence of and analyze risk factors for suction loss during femtosecond laser-assisted small incision lenticule extraction in the management of myopia or myopic astigmatism., Setting: Roayah Vision Correction Center, Alexandria, Egypt., Design: Retrospective comparative case-control study., Methods: All eyes that had femtosecond laser-assisted small-incision lenticule extraction for the correction of myopia and myopic astigmatism performed between August 2010 and April 2014 were included. Eyes that developed suction loss were identified. Their characteristics, including demographic data (age and sex), eye laterality, manifest refraction, flat keratometry (K) reading, steep K reading, K astigmatism, optical zone, central corneal thickness, and corneal cap diameter and thickness, were compared with those in randomly selected control eyes to determine the risk factors for developing suction loss., Results: Of the 3376 eyes that had femtosecond laser-assisted small-incision lenticule extraction during the study, 70 (2.1%) developed loss of suction. The incidence decreased with surgical experience (5.06% in 2010, 3.59% in 2011, 3.41% in 2012, 2.32% in 2013, and 1.84% in 2014), suggesting a learning curve. A multivariate logistic regression model showed that eyes with a larger cap diameter were significantly more likely to develop suction loss (P = .023; odds ratio, 9.60)., Conclusions: Surgical experience significantly decreased the risk for suction loss during femtosecond laser-assisted small incision lenticule extraction for the correction of myopia or myopic astigmatism but did not eliminate it. A larger cap diameter significantly increased the risk for developing the suction loss., Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned., (Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: The aim of this study was to develop and characterize a new contact lens-associated fungal keratitis rat model and to assess the ability of non-invasive spectral-domain optical coherence tomography (SD-OCT) to detect pathological changes in vivo in fungal keratitis., Methods: We used SD-OCT to image and measure the cornea of Sprague Dawley rats. Fusarium infection was initiated in the rat eye by fitting Fusarium solani-soaked contact lenses on the experimental eye, while the control animals received contact lenses soaked in sterile saline. The fungal infection was monitored with periodic slit-lamp examination and in vivo SD-OCT imaging of the rat eye, and confirmed by histology, counting of viable fungi in the infected rat cornea, and PCR with specific primers for Fusarium sp., Results: We imaged and measured the rat cornea with SD-OCT. Custom-made contact lenses were developed based on the OCT measurements. Incubation of contact lenses in a F. solani suspension resulted in biofilm formation. We induced contact lens-associated Fusarium keratitis by fitting the rat eyes for 4 h with the Fusarium-contaminated contact lenses. The SD-OCT images of the cornea correlated well with the slit-lamp and histopathological results and clearly defined clinical signs of infection, namely, increased corneal thickening, loss of epithelial continuity, hyper-reflective areas representing infiltrates, and endothelial plaques characteristic of fungal infection. Moreover, in three cases, SD-OCT detected the infection without any clear findings on slit-lamp examination. Infection was confirmed with histological fungal staining, PCR, and microbiological culture positivity., Conclusions: We developed a highly reproducible rat contact lens model and successfully induced contact lens-associated Fusarium keratitis in this model. The clinical presentation of contact lens-associated Fusarium keratitis in the rat model is similar to the human condition. SD-OCT is a valuable tool that non-invasively revealed characteristic signs of the fungal infection and could provide sensitive, objective monitoring in fungal keratitis.

Objective: To assess the use of an ultra-high-resolution (UHR) optical coherence tomography (OCT) as an adjuvant diagnostic tool in distinguishing ocular surface squamous neoplasia (OSSN) and pterygia., Design: Prospective case series., Participants: Thirty-four eyes of 34 patients with conjunctival lesions clinically suspicious for OSSN or pterygia., Methods: All patients were photographed and then imaged with a custom-built UHR OCT device. Subsequently, each patient underwent excisional or incisional biopsy with histopathologic diagnosis., Main Outcome Measures: Comparison of preoperative UHR OCT images and the corresponding histopathologic specimen; comparison of epithelial thickness between the 2 groups as measured by UHR OCT., Results: Preoperative UHR OCT images of OSSN demonstrated similarities to the histopathologic specimens. Both optical and pathologic specimens showed a thickened layer of epithelium, often with an abrupt transition from normal to neoplastic tissue. Likewise, preoperative UHR OCT images of patients with pterygia were well correlated with the histopathologic specimens. As opposed to OSSN, both UHR OCT and pathologic images of pterygia demonstrated a normal thin epithelium, with underlying thickening of the subepithelial mucosal layers. Differences in the measured epithelial thickness on UHR OCT between OSSN and pterygia were statistically significant, with an average epithelial thickness of 346 μm (standard deviation [SD], 167) in OSSN patients and 101 μm (SD, 22) in pterygium patients (P<0.001). By receiver operating characteristic curve, the sensitivity and specificity of UHR OCT for differentiating between OSSN and pterygia was found to be 94% and 100%, respectively, using a cutoff value of 142 μm., Conclusions: Ultra-high-resolution OCT may show promise as a noninvasive diagnostic tool to evaluate ocular surface lesions. In addition to a statistically significant difference in epithelial thickness, a significant degree of morphologic correlation with the histopathologic results demonstrates its potential in evaluating ocular surface squamous neoplasia and pterygia., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Developments in optical coherence tomography (OCT) have expanded its clinical applications for ultra-high resolution imaging of the anterior segment of the human eye. This review presents the latest advances for imaging the anterior segment of the eye using ultra-high resolution OCT (UHR-OCT). Unique applications of UHR-OCT technology in clinical and basic scientific laboratory research are discussed and a summary of the results is provided. The authors focused on the use of UHR-OCT for imaging of tear dynamics, contact lens interactions with the corneal surface, and in vivo histological diagnosis of disorders of the cornea, as well as the future direction in this field., (Copyright 2011, SLACK Incorporated.)