Christopher S. Sales

Purpose: The aim of this study was to quantify nighttime driving differences in patients with Fuchs endothelial corneal dystrophy (FECD) using the FDA-validated National Advanced Driving Simulator MiniSim. Methods: We conducted a pilot study to calculate sample size, followed by a prospective study with 6 patients with FECD and 6 controls. Participants underwent Snellen visual acuity (VA) testing, Mars contrast sensitivity (CS) assessment, and Scheimpflug tomography. Participants completed 3 simulated driving scenarios, identifying hazards while detection distances were tracked. Driving scenarios simulated glare conditions from oncoming headlights at night: “variable glare” modulated glare intensity with passing traffic, “constant glare” kept glare intensity fixed, and “no glare.” The primary outcome was hazard recognition under “variable glare.” Results: Age, CS, and VA did not differ significantly between groups. Anterior and posterior densitometry were worse in the FECD group versus controls (anterior: 37.9 ± 6.0 vs. 28.9 ± 1.5, P = 0.01; posterior: 20.1 ± 3.1 vs. 16.5 ± 1.0, P = 0.02). Patients with FECD recognized 14% fewer hazards than controls (variable glare: 81.8 ± 12.1 vs. 95.8 ± 4.7%, P = 0.03). Patients with FECD required being nearly twice as close to hazards to recognize them versus controls (76.5 ± 38.8 vs. 137.7 ± 51.9 ft; P = 0.04). Tomographic markers of subclinical corneal edema (r = −0.61, P = 0.03) and higher anterior densitometry values (r = −0.61; P = 0.04) correlated with shorter hazard detection distance under “constant glare.” Thicker central corneal thickness (variable glare: r = −0.60, P = 0.04) and higher posterior densitometry values correlated with lower hazard recognition scores (variable glare: r = −0.67, P = 0.02; constant glare: r = −0.65, P = 0.02). Conclusions: Despite normal VA and CS, patients with FECD performed significantly worse in driving simulations than controls. Driving disability was associated with tomographic measures of subclinical corneal edema and abnormal corneal densitometry.

Purpose: To investigate and compare the dimensional characteristics of Descemet membrane endothelial keratoplasty (DMEK) scrolls in single-scroll and double-scroll conformations at various ages and velocities. Methods: DMEK tissues from three donor pairs (ages 47, 62, and 69) were used to compare single-scroll and double-scroll widths under different velocities. Tissues were randomized and manipulated into single-scroll or double-scroll conformation using a syringe pump connected to an hourglass-shaped glass tube. All scrolls were passed through the tube at three different velocities set by syringe pump settings, and high-speed videography at 2000 frames per second captured scroll dimensions. Scroll dimensions were measured using IDT Motion Studio software. Results: Single-scrolled DMEK tissue was narrower than double-scrolled tissue across all donor ages. Double-scrolled tissue width remained relatively unchanged regardless of age or velocity. Significant differences in scroll width between single and double scrolls were observed in the 47-year-old donor tissue at all velocities (P P = 0.03 and P = 0.01, respectively). In the 69-year-old donor tissue, significant differences in scroll width between single and double scrolls were observed only at high velocities (P = 0.003). Single-scroll width decreased with increasing velocity for 47-year-old and 62-year-old donor tissues (P P = 0.03), but not for the 69-year-old donor tissue (P = 1.0). Conclusions: There is a significant difference in scroll width between single-scrolled and double-scrolled tissues at high speeds. These differences become less significant as scrolls increase in age and velocity decreases.

Some anterior chambers do not readily shallow because of insufficient posterior pressure and/or very deep anterior chamber anatomy, which can make unscrolling descemet membrane endothelial keratoplasty (DMEK) tissue more challenging with an unmodified tap technique. We present a hands-free method for augmenting posterior pressure by temporarily tucking cellulose sponges under the blades of the eyelid speculum. The sponges transfer some of the eyelid speculum’s weight onto the bulbar surface posterior to the iris, thereby indenting the sclera and causing the iris diaphragm to bulge further forward. This hands-free technique can transform a potentially challenging DMEK case into a more straightforward one by facilitating both a shallow anterior chamber and a bimanual unscrolling technique. However, it only works in bicameral eyes with a vitreous body (e.g., an eye with penetrating keratoplasty, vitreous syneresis, and axial myopia) and will not work in unicameral eyes after vitrectomy (e.g., an eye with an Anterior Chamber Intraocular Lens (ACIOL)).

Purpose: 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 < 0.001) and narrow (R² = −0.84, P < 0.001) tubes. There was a significant, direct correlation between scroll velocity and length in both the wide (R² = 0.84, P < 0.001) and narrow (R² = 0.83, P < 0.001) tubes. The resting widths of the scrolls were 105% and 207% wider than the wide and narrow tubes, respectively. All transits recorded scroll widths that were equal to or smaller than their respective tube's internal diameter. Conclusions: There is a significant, inverse correlation between DMEK scroll velocity and width as well as a direct correlation between scroll velocity and length, allowing DMEK scrolls to transit through a tube that is narrower than its resting width without sustained lumen wall contact.

Purpose: The aims of this study were (1) to compare “front” and “rear” methods for loading Descemet membrane endothelial keratoplasty (DMEK) tissue into both micro-Jones and standard-Jones tubes and (2) to evaluate the efficacy of a cone-shaped glass funnel adapter designed to make loading DMEK tissue safer for corneal endothelial cells. Methods: The corneal endothelium was stained with 0.06% trypan blue to confirm equivalence between mate corneas. The tissues were then processed using the Iowa Lions Eye Bank standard DMEK protocol. In comparison 1, one mate was loaded into the rear of a micro-Jones or standard-Jones tube and the other was loaded into the front of the same tube. In comparison 2, one mate was loaded into the front of the micro-Jones tube and the other was loaded through the cone-shaped funnel adapter into the rear. All tissues were ejected through the front of the modified Jones tubes and assessed for endothelial cell loss (ECL) with calcein AM staining, FIJI, and Trainable Weka Segmentation; scroll widths were measured digitally. Results: There were no statistically significant differences in ECL between front and rear loading [micro (N = 6 pairs): front 15.74% vs. rear 17.95%; standard (N = 6 pairs): front 19.58% vs. rear 19.17%; all P > 0.05]. DMEK scrolls loaded with the funnel adapter exhibited lower ECL compared with scrolls loaded through the front [micro (N = 8 pairs): front 13.53% vs. loading funnel 2.40%; P < 0.001]. Loading with the adapter was not faster (front 6.66 seconds vs. loading funnel 5.52 seconds; P = 0.24). Conclusions: Using a cone-shaped DMEK loading funnel may reduce ECL sustained during preloading.

Purpose: The aim of this study was to define risks for corneal transplantation associated with fibrous ingrowth among first-time transplant recipients. Methods: We performed a retrospective case–control study of patients with a histopathologic diagnosis of fibrous ingrowth between 2002 and 2019. Patients with fibrous ingrowth from a first corneal specimen were included. Those with incomplete records were excluded. A 1:2 case–control ratio was used. Controls were matched using surgical indication, surgery year, transplantation method, sex, and age. Results: Seventy-eight eyes (76 patients) were included and matched with 160 control eyes. The incidence of fibrous ingrowth found on a first corneal transplant was 0.6% per year. The most common keratoplasty indications were pseudophakic corneal edema (n = 25, 32%) and aphakic corneal edema (n = 15, 19%). Cases were more likely to have a history of ocular trauma (odds ratio [OR], 2.94; 95% CI, 1.30–6.30; P = 0.007), uveitis (OR, 2.73; 95% CI, 1.12–6.63; P = 0.022), retinal detachment or previous retinal surgery (OR, 2.40; 95% CI, 1.34–4.30; P = 0.003), glaucoma tube-shunt surgery (OR, 2.70; 95% CI, 1.29–5.65; P = 0.007), aphakia (OR, 3.02; 95% CI, 1.61–5.67; P = 0.0004), or iris derangement (OR, 10.52; 95% CI, 5.45–20.30; P <0.0001). A multivariate logistic regression model using iris derangement, history of ocular trauma, history of uveitis, and history of cataract surgery demonstrated 81% sensitivity and 66% specificity in predicting presence of fibrous ingrowth. Conclusions: A history of ocular trauma, uveitis, retinal detachment or previous retinal surgery, glaucoma tube-shunt surgery, aphakia, and iris derangement are risks for detecting fibrous ingrowth among first-time keratoplasty recipients. Patients with these conditions should be monitored closely for corneal decompensation.

Recently is was discovered in various applications that many physical and chemical properties of water change their temperature dependence between about 35 and 60 degrees Celsius. In particular, heat conductance, light absorption, and surface tension all change their temperature dependence. These drastic changes were associated with water gradually changing its mesoscopic structure: while at the higher temperatures water is a uniform media (amorphous state), at the temperatures below transition it consists of many nano-to-micro-scale clusters (crystalline state). This transition is similar to the second order phase transition. In the present paper we show that treating water with non-thermal plasma (adding plasma-created active compounds) can lower the temperature of the transition and thus cause a significant change in such physical quantities as surface tension, viscosity, freezing rate, and wettability and washability. We present analytical estimates of the transition temperature shift based on the Debya-Huckel theory. We discuss the produce-washing experiments that illustrate the predicted effects.

Tele-ophthalmology is a rapidly evolving and exciting field that has become increasingly relevant amidst the current global pandemic. With advancements in technology, many components of an evaluation previously possible only in an office setting are becoming possible remotely, paving the way for at-home visits. Examples of these technologies include measurement of visual acuity using smartphones, remote monitoring of intraocular pressure using self-administered tonometers or implantable sensors, and use of digitally acquired slit-lamp or smartphone images for diagnosis of anterior segment pathology. While many examples showcasing the utility of telemedicine have been shown for diseases such as diabetic retinopathy, concerted efforts are needed to develop similar technology for anterior segment diseases. As technology continues to advance, it may be possible to diagnose and manage more anterior segment disease with telemedicine.

Purpose: To examine tissue loss rates, processing time, and primary graft failure (PGF) of “prestripped-only” Descemet membrane endothelial keratoplasty (DMEK) grafts at a single eye bank and how these parameters changed after the introduction of steps to preload tissue among experienced processors. Methods: Tissue loss and processing time during DMEK graft preparation as well as PGF were analyzed retrospectively at a single eye bank between 2012 and 2018. Outcomes were assessed in consecutive grafts before and after the introduction of preloading to the eye bank's standard operating procedure. Results: A total of 1326 grafts were analyzed, composed of the first 663 preloaded DMEK grafts and, for comparison, the 663 DMEK grafts processed immediately before starting the preloaded service. Mean processing time increased from 17.0 ± 3.9 minutes to 26.0 ± 5.4 minutes with the advent of preloading (P < 0.01). Initially, average processing time increased dramatically, with a maximum processing time of 51 minutes, before regressing to the average. No significant difference in the rate of tissue wastage was observed before versus after the implementation of preloaded DMEK (1.2% vs. 1.7%, P = 0.48). PGF occurred in 7 grafts before the preloaded service and 10 grafts after starting the service (1.6% vs. 2.3%, P = 0.47). Conclusions: Preloading does not affect tissue wastage for experienced technicians or the PGF rate but increases processing time. Eye banks that are considering adding preloading to their standard operating procedure may need to account for longer processing times in their daily operations.

Purpose: To investigate the antimycotic activity of amphotericin B deoxycholate that has been previously frozen for 28 days before supplementation of Optisol-GS. Methods: Triplicate Optisol-GS samples were inoculated with 10⁶ colony-forming units (CFU) of Candida albicans. Each set of triplicate cultures was supplemented with 2.5 μg/mL of amphotericin B that was either freshly resuspended and never frozen, frozen overnight at −20°C and thawed, or frozen at −20°C for 4 weeks and thawed. The cultures were stored at 4°C, with aliquots taken at 0, 6, 24, and 72 hours for quantification. The efficacy of each preparation of amphotericin B in reducing C. albicans growth was assessed at these time points. Results: Six hours after antifungal supplementation, there was a 1.33 log₁₀ CFU reduction with freshly resuspended amphotericin B, compared with a 1.31 log₁₀ reduction with amphotericin B that was frozen overnight (P = 0.20) and a 1.18 log₁₀ reduction with amphotericin B that was frozen for 4 weeks (P = 0.05). After 72 hours, there was a 2.72 log₁₀ CFU reduction with freshly resuspended amphotericin B, a 2.64 log₁₀ CFU reduction with amphotericin B that was frozen overnight (P = 0.45), and a 2.18 log₁₀ CFU reduction with amphotericin B that was frozen for 4 weeks (P = 0.05). Conclusions: Previously frozen amphotericin B remains highly effective against C. albicans. Optisol-GS supplemented with 2.5 μg/mL amphotericin B that was frozen for 4 weeks at −20°C resulted in >90% CFU reduction by 6 hours and >99% reduction by 72 hours.