David A. Belyea

Influence of surgery simulator training on ophthalmology resident phacoemulsification performance.

PURPOSE: To determine whether the use of an eye‐surgery simulator during ophthalmology residency training improves cataract surgery performance. SETTING: Department of Ophthalmology, Medical Faculty Associates, George Washington University, Washington, DC, USA. DESIGN: Comparative case series. METHODS: Residents were divided into a simulator group and a nonsimulator group based on the inclusion or absence of the eye‐surgery simulator in residency training. Consecutive resident cataract surgeries with the same attending surgeon were retrospectively reviewed. The phaco time and percentage power and intraoperative complications in each case were recorded. The adjusted phaco time in each case was calculated. RESULTS: The study reviewed 592 surgeries. The mean values for phaco time, percentage phaco power, adjusted phaco time, complication rates, and complication grade were 1.88 minutes (range 0.11 to 7.20 minutes), 25.32% (range 2.2% to 50.0%), 47.58 minutes (range 0.24 to 280.80 minutes), 0.04, and 2.33, respectively, in the simulator group (n = 17) and 2.41 minutes (range 0.04 to 8.33 minutes), 28.19% (range 8.0% to 70.0%), 71.85 minutes (range 0.32 to 583.10 minutes), 0.06, and 2.47, respectively, in the nonsimulator group (n = 25). The Student t tests showed a statistically significant between‐group difference in mean phaco time (P<.002), adjusted phaco time (P<.0001), and percentage phaco power (P<.0001). Regression analysis showed a significantly steeper slope of improvement in mean phaco time and power in the nonsimulator group than in the simulator group (P<.0001). CONCLUSIONS: Residents who trained using the simulator had shorter phaco times, lower percentage powers, fewer intraoperative complications, and a shorter learning curve. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Midterm follow-up results of combined phacoemulsification, lens implantation, and mitomycin-C trabeculectomy procedure.

Purpose:This study evaluates the visual, refractive, perimetric, and intraocular pressure (IOP) results following combined phacoemulsification, lens implantation, and trabeculectomy with mitomycin-C. Methods:Twenty-nine consecutive eyes of 26 patients with cataract and glaucoma that had undergone combined phacoemulsification, posterior chamber lens implantation, and limbus-based trabeculectomy with mitomycin-C applied after the cataract removal and trabeculectomy had a minimal follow-up time of 12 months (mean follow-up 20 ± 6.3 months). Each eye was evaluated for visual acuity, corneal astigmatism. IOP, bleb persistence, optic nerve stability, visual field status, and complications. Goldmann visual fields were assessed by a semi-quantitative method and threshold static perimetry by statistical indices of diffuse damage (mean deviation) and focal loss (corrected pattern standard deviation). The preoperative and postoperative results were compared by Students t-test. Results:All eyes that were free of pre-existing macular disease demonstrated significant improvement in visual acuity by at least 4.5 lines of Snellen acuity. Postoperative astigmatism was negligible (0.29 diopters). The average IOP reduction was 6.5 mm Hg, with the one year or more average of 13.4 mm Hg on virtually no antiglaucoma medicines (0.2 ± 0.5). Functioning filtering blebs persisted in 86% of eyes. Of 11 patients tested with pre- and postoperative Goldmann perimetry, only two showed visual field defect progression despite IOPs <15 mm Hg. Of the 12 eyes with pre- and postoperative static threshold perimetry, the mean deviation deteriorated in nine eyes (p = 0.003). The corrected pattern standard deviation changes were not statistically significant (p = 0.69). Complications (including two cases of late-onset endophthalmitis) were comparable with other studies reporting filtration surgery with adjunctive antimetabolites. We detected no untoward effects of applying the mitomycin at the end of the procedure rather than at the beginning. Conclusions:The combined procedure technique that we describe appears to be effective at restoring visual acuity and significantly reducing IOP. Nevertheless, many visual fields showed continued, diffuse glaucomatous progression in the year or two following surgery and the development of late endophthalmitis in two eyes is a concern.

Evaluation of optic disc measurements with the glaucoma-scope.

PurposeWe evaluated the Glaucoma-Scopes ability to acquire images of the optic disc, the reproducibility of its analysis, and the comparison between it and expert evaluation. MethodsOne hundred and sixty-eight patients with satisfactory standard fundus photography were referred for Glaucoma-Scope analysis. Characteristics of eyes in which Glaucoma-Scope analysis could not be obtained were evaluated. Eight glaucoma patients (15 eyes) were quantitatively evaluated: inter- and intraobserver reproducibility of the Glaucoma-Scope analyses were calculated utilizing weighted Kappa index of agreement and coefficient of variation. The Glaucoma-Scope cup-to-disc ratio was calculated from the gray scale analysis and compared to the ratio as evaluated by a glaucoma expert. ResultsGlaucoma-Scope analysis was not achieved in 14% of a total of 336 eyes of 168 patients. The conditions associated with the inability to obtain a satisfactory image were hyperpigmented fundi, pseudophakia, aphakia, corneal opacities, cataract, and contact lenses. The quantitative analysis of the 15 patients showed small inter- and intraobserver means of the coefficient of variation (0.136 ± 0.023 and 0.129 ± 0.016) and SD (0.063 ± 0.0056 and 0.064 ± 0.0077) and moderate-substantial intra- and interobserver agreement (weighted K = 0.427 ± 0.1 and 0.61 ± 0.14, respectively). Significant disagreement (weighted K = - 0.11, p = 0.0023) was found between Glaucoma-Scope (mean 0.52 ± 0.064) and experts evaluations (0.673) of the cup-to-disc ratio. ConclusionsThe inter- and intraobserver reliability and low variation of the Glaucoma-Scope readings indicates moderate to substantial reproducibility for detecting changes in optic discs topography under selected conditions. However, eyes with moderate cataract, aphakia, pseudophakia, mild corneal opacity, darkly pigmented fundi or myopia were inconsistently analyzable. In a small group of randomly selected eyes there was very low agreement between the glaucoma experts evaluation of the optic disc and that of the Glaucoma-Scope. These findings raise questions about the usefulness of the instrument as a diagnostic tool for glaucoma but show promise for detecting change when good images are possible.

Effects of In-vivo Application of Cold Atmospheric Plasma on Corneal Wound Healing in New Zealand White Rabbits

Cold Atmospheric Plasma (CAP) has been shown to influence tissue wound healing but little is known about the impact of CAP on healthy corneal tissues and their ability to respond to injuries. The objective of this study is to examine the effect of CAP on wound healing after corneal epithelial and basement membrane ablation in New Zealand white rabbits. The rabbits were assigned into three groups. Ten Rabbits from two groups underwent a 6 mm corneal ablation to the right eyes. After ablation, five rabbits in group (A) received 2 minutes of CAP whereas the other five rabbits (B) were not treated with CAP. A third group (C) included two rabbits and received CAP without ablation. Eyes monitored for corneal haze, epithelial healing, lens clarity and any signs of inflammation. At 24 hours, two rabbits from group A and two from group B were sacrificed to harvest the corneas. Twenty days, all remaining rabbits in groups A, B, and C were sacrificed and corneas were harvested. Corneas were fixed in formalin and stained with H&E or used for immunofluorescence microscopy to assess scar formation using antibodies against fibronectin and a-smooth muscle actin. At 24 hours, corneas from group A had average epithelial defect of 9.25 mm2 on day 1 whereas those from group B had average defect of 12.05 mm2, a difference of 2.8 mm2 (P=0.57). H & E stained corneal sections didn’t show abnormal responses to injury at 24 hours and 20 days. Epithelial thickness and stromal cell counts 20 days after injury showed no significant differences. Analysis of immunofluorescence microscopy images showed no differences between all groups. In conclusion, CAP application to cornea doesn’t appear to have obvious adverse effects. CAP does not interfere with rate of wound closure or induce increased inflammation. CAP did not have an effect on corneal wound healing or lead to scar formation.

Feasibility of telerobotic microsurgical repair of corneal lacerations in an animal eye model.

We evaluated the feasibility of telerobotic microsurgical repair of corneal lacerations. The telerobotic microsurgical device consisted of a Robotic Slave Micromanipulator Unit (RSMU) coupled to a Telepresence Surgical System (TeSS). Five mm central full-thickness corneal wounds were fashioned in five enucleated rabbit eyes and repaired remotely using the telerobotic system. Five additional eyes were also repaired by hand using a standard technique. The primary outcome measure was creation of a watertight seal. All eyes in both groups maintained an intraocular pressure (IOP) of 25 mm Hg without leak. The mean repair time was 80 min (range 50–130) with telerobotic surgery compared to 8 min (range 7–9) by hand. Histological evaluation showed that suture placement was similar in robotically assisted repair and manual repair. Subjectively, the telerobotic system provided adequate three-dimensional visualization of the surgical field. The study showed that a surgeon could close standardized corneal wounds using the telerobotic system. The potential benefits of remote eye surgery include improved access, surgical teleconsultation and telementoring.

Surface Acoustic Wave devices for ocular drug delivery

In this work we are reporting on the development of a novel Surface Acoustic Wave (SAW) device based on MEMS technology for drug delivery in the treatment of ocular diseases. The miniaturized SAW drug delivery device will be placed on the eye surface to allow non-invasive long-term drug application based on the programmed timeline and electronic control of a drug regiment. This novel drug delivery method is expected to lead to better clinical outcomes in the treatment of various eye diseases, and improved patient compliance with therapy. The device can be programmed for delivery of precise amounts of drugs at predetermined times over several months, and will use acoustic streaming to push the drug outside of the reservoir. Our modeling results were obtained using COMSOL multiphysics program and Coventor microfluidic simulator. Different force values were applied to investigate the force necessary to push the drug through the outlet.

Indirect cyclopexy for treatment of a chronic traumatic cyclodialysis cleft with hypotony

Cyclodialysis cleft is a rare clinical finding and therefore, reports on surgical repair techniques in the literature are limited. Additionally, hypotony can make repair technically challenging. We share a novel, simple surgical approach to management of a case of chronic traumatic cyclodialysis cleft with a successful outcome.

Peripheral laser iridoplasty opens angle in plateau iris by thinning the cross-sectional tissues

Plateau iris syndrome has been described as persistent angle narrowing or occlusion with intraocular pressure elevation after peripheral iridotomy due to the abnormal plateau iris configuration. Argon laser peripheral iridoplasty (ALPI) is an effective adjunct procedure to treat plateau iris syndrome. Classic theory suggests that the laser causes the contraction of the far peripheral iris stroma, “pulls” the iris away from the angle, and relieves the iris-angle apposition. We report a case of plateau iris syndrome that was successfully treated with ALPI. Spectral domain optical coherence tomography confirmed the angle was open at areas with laser treatment but remained appositionally closed at untreated areas. Further analysis suggested significant cross-sectional thinning of the iris at laser-treated areas in comparison with untreated areas. The findings indicate that APLI opens the angle, not only by contracting the iris stroma, but also by thinning the iris tissue at the crowded angle. This is consistent with the ALPI technique to aim at the iris as far peripheral as possible. This case also suggests that spectral domain optical coherence tomography is a useful adjunct imaging tool to gonioscopy in assessing the angle condition.

Herpetic Stromal Keratitis following Selective Laser Trabeculoplasty

This is a case report describing two cases of disciform corneal edema following uncomplicated selective laser trabeculoplasty (SLT) thought to be secondary to herpes simplex virus (HSV) given the presence of a dendrite, decreased corneal sensation, corneal thinning, and response to therapy with oral and topical antivirals. Corneal edema after SLT treatment has been reported before, but the etiology has been unclear. Our cases highlight HSV as a likely etiology, which may help with prevention and better management of such cases in the future.

Telerobotic contact transscleral cyclophotocoagulation of the ciliary body with the diode laser.

To assess the feasibility of using the Robotic Slave Micromanipulator Unit (RSMU) to remotely photocoagulate the ciliary body for the treatment of glaucoma with the diode laser. In fresh unoperated enucleated human eyes, the ciliary body was destroyed either with a standard contact transscleral cyclophotocoagulation ‘by hand’ diode laser technique, or remotely using the RSMU. The treated sections were fixed in formalin, paraffin-embedded, and stained with hematoxylin and eosin. Histological evaluation was performed by a masked observer using a standardized grading system based on the amount of damage to the ciliary body to evaluate effectiveness of treatment. Both methods of contact transscleral cyclophotocoagulation showed therapeutic tissue disruption of the ciliary processes and both the non-pigmented and pigmented ciliary epithelium. Histology examination of remote robotic contact transscleral cyclophotocoagulation and “by hand” technique produced similar degrees of ciliary body tissue disruption. Remote diode laser contact transscleral cyclophotocoagulation of the ciliary body in fresh enucleated human eyes is possible with the RSMU. Therapeutic tissue disruption of the ciliary body was achieved. Additional study is necessary to determine the safety and efficacy of robotically-delivered cyclophotocoagulation in live eyes.