Cornea

Deformable Biomechanics of DMEK Tissue Scrolls Traveling Through Narrow Lumens: The Inverse Relationships Between Fluid Velocity, Scroll Width, and Wall Contact and Their Clinical Implications for Preloading

imagePurpose:

The aim of this study was to evaluate Descemet membrane endothelial keratoplasty (DMEK) scroll width and length in relation to variable velocities as the tissue transits through wide and narrow lumen glass tubes.

Methods:

Sets of DMEK tissue were processed using the Iowa Lions Eye Bank standard DMEK protocol and were passed through 2 glass tube widths at variable speeds. Two hourglass-shaped glass tubes were created, one “wide” and one “narrow.” A syringe pump, valve, and pressure gauge were used to modulate tissue speed through each tube. For both tube sizes, DMEK tissue was passed through their lumens with incrementally increasing velocity and visualized with a high-speed camera at frame rates from 1000 to 8000 fps. Scroll width and length were measured using IDT Motion Studio software and digital calipers.

Results:

There was a significant, indirect correlation between scroll velocity and width in both the wide (R2 = −0.98, P

By Kigin, Matthew; Revis, Benjamin; Vigmostad, Sarah; Sales, Christopher, ago

Quality and Agreement With Scientific Consensus of ChatGPT Information Regarding Corneal Transplantation and Fuchs Dystrophy

imagePurpose:

ChatGPT is a commonly used source of information by patients and clinicians. However, it can be prone to error and requires validation. We sought to assess the quality and accuracy of information regarding corneal transplantation and Fuchs dystrophy from 2 iterations of ChatGPT, and whether its answers improve over time.

Methods:

A total of 10 corneal specialists collaborated to assess responses of the algorithm to 10 commonly asked questions related to endothelial keratoplasty and Fuchs dystrophy. These questions were asked from both ChatGPT-3.5 and its newer generation, GPT-4. Assessments tested quality, safety, accuracy, and bias of information. Chi-squared, Fisher exact tests, and regression analyses were conducted.

Results:

We analyzed 180 valid responses. On a 1 (A+) to 5 (F) scale, the average score given by all specialists across questions was 2.5 for ChatGPT-3.5 and 1.4 for GPT-4, a significant improvement (P

By , ago

Donor Risk Factors and Environmental Conditions Associated With Poor-Quality Corneas: An Analysis of the Central Eye Bank of Iran (2018–2021)

imagePurpose:

The purpose of this study was to investigate the donor risk factors and environmental conditions associated with poor-quality corneas using the database of the Central Eye Bank of Iran over 4 years.

Methods:

This cohort study was conducted on the recorded data of all donated corneas at the Central Eye Bank of Iran database from March 2018 to March 2022. Donors’ characteristics and tissue variables were extracted from the database. The final corneal quality was determined based on slitlamp biomicroscopic observations and the results of specular microscopy. Environmental variables were also obtained from reliable resources. Risk factors for poor-quality corneas were calculated using logistic mixed-effect regression analysis. All analyses were performed with STATA 17.0. The significance level of 0.05 was considered for all the analyses.

Results:

The data of 20,625 eyes of 10,601 donors were evaluated. We found that donor age had an inverse correlation with endothelial cell density (r = −0.28, P

By , ago

Corneal Superficial Plaque Formation After Recombinant Human Nerve Growth Factor Use in a Patient With Neurotrophic Keratopathy and Limbal Stem Cell Deficiency From Mucous Membrane Pemphigoid

Purpose:

The aim of this study was to report a rare observation of corneal superficial plaque formation after topical recombinant human nerve growth factor (rhNGF) treatment for a nonhealing epithelial defect in a patient with advanced mucous membr…

By Surico, Pier Luigi; Kaufman, Aaron R.; Lin, Julie; Dehghani, Shima; Dana, Reza, ago

Evaluating Moisture Migration in Schirmer Test Strips: Exploring Brand-Specific Variations and Introducing Calibration and Conversion Methods

imagePurpose:

Schirmer test results are widely used for ocular surface disease assessment, but Schirmer strips are not standardized. We compare the characteristics and tear volume with millimeter moisture migration in different brands of Schirmer strips and introduce methods for volume-based, brand-independent calibration.

Methods:

Physical parameters of Haag-Streit, EagleVision, TearFlo, Contacare, and MIPL/A6 Schirmer strip brands were compared. Schirmer strip millimeter moisture migration distances were assessed 5 minutes after application of incremental microliter volumes of human tears. Linear regression analysis of data points from each Schirmer strip brand was performed, and the root-mean-square deviation of data points to the best-fit linear regression was calculated. Calibration correction was performed by converting migration distance to the corresponding tear volume. A reference table and calibration method formulas were created.

Results:

Schirmer strips differed in design, shape, and manufacturing precision. Strip width, weight, and length were different between the 5 brands (P

By Magone, M. Teresa; Schuck, Peter, ago