NQO1 downregulation potentiates menadione-induced endothelial-mesenchymal transition during rosette formation in Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) is a genetic and oxidative stress disorder of post-mitotic human corneal endothelial cells (HCEnCs), which normally exhibit hexagonal shape and form a compact monolayer compatible with normal corneal functioning and clear vision. FECD is associated with increased DNA damage, which in turn leads to HCEnC loss, resulting in the formation rosettes and aberrant extracellular matrix (ECM) deposition in the form of pro-fibrotic guttae. Since the mechanism of ECM deposition in FECD is currently unknown, we aimed to investigate the role of endothelial-mesenchymal transition (EMT) in FECD using a previously established cellular in vitro model that recapitulates the characteristic rosette formation, by employing menadione (MN)-induced oxidative stress. We demonstrate that MN treatment alone, or a combination of MN and TGF-β1 induces reactive oxygen species (ROS), cell death, and EMT in HCEnCs during rosette formation, resulting in upregulation of EMT- and FECD-associated markers such as Snail1, N-cadherin, ZEB1, and transforming growth factor-beta-induced (TGFβI), respectively. Additionally, FECD ex vivo specimens displayed a loss of organized junctional staining of plasma membrane-bound N-cadherin, with corresponding increase in fibronectin and Snail1 compared to ex vivo controls. Addition of N-acetylcysteine (NAC) downregulated all EMT markers and abolished rosette formation. Loss of NQO1, a metabolizing enzyme of MN, led to greater increase in intracellular ROS levels as well as a significant upregulation of Snail1, fibronectin, and N-cadherin compared to normal cells, indicating that NQO1 regulates Snail1-mediated EMT. This study provides first line evidence that MN-induced oxidative stress leads to EMT in corneal endothelial cells, and the effect of which is further potentiated when redox cycling activity of MN is enhanced by the absence of NQO1. Given that NAC inhibits Snail-mediated EMT, this may be a potential therapeutic intervention for FECD.

Dry eye after laser in-situ keratomileusis

Laser-assisted in-situ keratomileusis (LASIK) is one of the most commonly performed refractive procedures with excellent visual outcomes. Dry eye syndrome is one of the most frequently seen complications after LASIK, with most patients developing at least some mild dry eye symptoms postoperatively. To achieve improved visual outcomes and greater patient satisfaction, it is essential to identify patients prone to dry eyes preoperatively, and initiate treatment early in the course. Enhanced understanding of the pathophysiology of post-LASIK dry eye will help advance our approach to its management.

Exposure, entropion, and bilateral corneal ulceration in a newborn as a manifestation of chromosome 22 q11.2 duplication syndrome

Purpose

Chromosome 22q11.2 micro-duplication syndrome (MDS), is a rare autosomal dominant condition, with a highly variable phenotype that ranges from unremarkable and asymptomatic, to fatal due to cardiovascular defects. Hypertelorism, downslanting palpebral fissures, superior displacement of the eyebrows, and ptosis are the most commonly reported ocular manifestations. Here, we report a newborn with bilateral exposure, entropion, and corneal ulceration related to 22q11.2 MDS.

Observation

A newborn girl presented with bilateral upper eyelid entropion, bilateral lower eyelid ectropion, and lagophthalmos. She subsequently developed bilateral corneal ulcers. Topical antibacterial drops, bandage contact lenses, medroxyprogesterone 1%, and fluorometholone 0.1%, together with partial tarsorrhaphy and correction of eyelid malposition, were used to treat the ulcers and address the underlying issues of exposure and entropion. Genetic testing revealed chromosome 22q11.2.MDS; further evaluation revealed systemic manifestations of this syndrome. The ocular surface healed well with gradual improvement of corneal opacification as well as bilateral partial tarsorrhaphy.

Conclusion and importance

This report is the first that describes a newborn with 22q11.2 MDS presenting with sight-threatening corneal ulceration. Entropion, ectropion, and lagophthalmos were identified and treated, allowing for healing of the corneal surface. Genetic testing revealed a syndrome not known to be associated with eyelid abnormalities and corneal ulceration, but with other important systemic and ocular implications. Bilateral partial tarsorrhaphy should not be excluded as a treatment option for infants who fail more conservative measures for the treatment of exposure.

The Current Burden and Future Solutions for Preoperative Cataract-Refractive Evaluation Diagnostic Devices: A Modified Delphi Study

Purpose

To obtain consensus on the key areas of burden associated with existing devices and to understand the requirements for a comprehensive next-generation diagnostic device to be able to solve current challenges and provide more accurate prediction of intraocular lens (IOL) power and presbyopia correction IOL success.

Patients and Methods

Thirteen expert refractive cataract surgeons including three steering committee (SC) members constituted the voting panel. Three rounds of voting included a Round 1 structured electronic questionnaire, Round 2 virtual face-to-face meeting, and Round 3 electronic questionnaire to obtain consensus on topics related to current limitations and future solutions for preoperative cataract-refractive diagnostic devices.

Results

Forty statements reached consensus including current limitations (n = 17) and potential solutions (n = 23) associated with preoperative diagnostic devices. Consistent with existing evidence, the panel reported unmet needs in measurement accuracy and validation, IOL power prediction, workflow, training, and surgical planning. A device that facilitates more accurate corneal measurement, effective IOL power prediction formulas for atypical eyes, simplified staff training, and improved decision-making process for surgeons regarding IOL selection is expected to help alleviate current burdens.

Conclusion

Using a modified Delphi process, consensus was achieved on key unmet needs of existing preoperative diagnostic devices and requirements for a comprehensive next-generation device to provide better objective and subjective outcomes for surgeons, technicians, and patients.