Induction of cataracts of varying degrees of hardness in human eyes obtained postmortem for cataract surgeon training

Comparison of methods to experimentally induce opacification and elasticity change in ex vivo porcine lenses

At the moment, cataract, which is the opacification of the eye's lens, can only be treated by surgery. In order to develop and test new pharmacological treatment strategies for the disease, there is a need for an appropriate in vitro model using ex vivo animal lenses. In this study, porcine lenses were incubated in either culture medium, glucose, triamcinolone acetonide, sodium chloride, hydrogen peroxide, sodium selenite, neutral buffered formalin, or were exposed to microwave heating to experimentally induce lens opacification. Changes in the lens morphology, weight, size, and elasticity were monitored 7 days after treatment. The fastest induction of dense opacification was seen in lenses exposed to sodium chloride, neutral buffered formalin, and microwave heating. No change in the size and weight of the lenses were detected, whereas loss in elasticity could be detected in lenses treated with formalin solution or microwave heating. Thus, neutral buffered formalin- and microwave-treated ex vivo porcine lenses seem to be a suitable model for mature cataracts, whereas hypertonic sodium chloride may be useful for studies on osmolarity-induced lens opacification.

Animal and cadaver human eyes for residents' surgical training in ophthalmology

In ophthalmology residency programs surgical training plays a vital role in creating confident and skillful surgeons. As almost all ophthalmic surgery needs microscope training, creating a well-taught environment for hand-eye coordination, ocular tissue handling, and anticipation of complications is essential. Wet lab training with animal or cadaver human eyes offers diverse possibilities. We conducted a thorough literature search on various databases to identify the existing literature on wet labs. The results revealed constructive efforts for training novice surgeons in all surgical ophthalmology subspecialties. Wet lab models were initially used only to practice cataract surgery; however, now various complex ocular procedures can be practiced. Ocular surface, corneal, iris, lenticular, scleral, vitreoretinal, extraocular, eyelid, and other adnexal surgeries were reproduced and mastered in many ways. Importantly, with repeated surgical practice, residents gained an increasing level of confidence with enhanced surgical accuracy. In addition, we propose a few novel techniques of various other procedures.

Essentials of setting up a wet lab for ophthalmic surgical training in COVID-19 pandemic

Wet labs are an extremely important training tool, especially in times of a global COVID-19 pandemic, where surgical training can be minimal. They help the trainee learn and practice in a risk-free environment, without an imminent of a complication or failure, also allowing them the chance to execute the steps of a surgery repeatedly. We summarize all the key ingredients required from setting up a wet lab to improve the surgical skill of the trainees. The review also discusses various eyeball fixating devices, preparation of the eye for various types of ocular surgeries, and the role of simulation-based training in today's scenario.

A systematic review of simulation-based training tools for technical and non-technical skills in ophthalmology

To evaluate all simulation models for ophthalmology technical and non-technical skills training and the strength of evidence to support their validity and effectiveness. A systematic search was performed using PubMed and Embase for studies published from inception to 01/07/2019. Studies were analysed according to the training modality: virtual reality; wet-lab; dry-lab models; e-learning. The educational impact of studies was evaluated using Messick's validity framework and McGaghie's model of translational outcomes for evaluating effectiveness. One hundred and thirty-one studies were included in this review, with 93 different simulators described. Fifty-three studies were based on virtual reality tools; 47 on wet-lab models; 26 on dry-lab models; 5 on e-learning. Only two studies provided evidence for all five sources of validity assessment. Models with the strongest validity evidence were the Eyesi Surgical, Eyesi Direct Ophthalmoscope and Eye Surgical Skills Assessment Test. Effectiveness ratings for simulator models were mostly limited to level 2 (contained effects) with the exception of the Sophocle vitreoretinal surgery simulator, which was shown at level 3 (downstream effects), and the Eyesi at level 5 (target effects) for cataract surgery. A wide range of models have been described but only the Eyesi has undergone comprehensive investigation. The main weakness is in the poor quality of study design, with a predominance of descriptive reports showing limited validity evidence and few studies investigating the effects of simulation training on patient outcomes. More robust research is needed to enable effective implementation of simulation tools into current training curriculums.

Goat's eye integrated with a human cataractous lens: A training model for phacoemulsification

A relatively simple and inexpensive technique to train surgeons in phacoemulsification using a goat's eye integrated with a human cataractous nucleus is described. The goat's eye is placed on a bed of cotton within the lumen of a cylindrical container. This is then mounted on a rectangular thermocol so that the limbus is presented at the surgical field. After making a clear corneal entry with a keratome, the trainer makes a 5–5.5 mm continuous curvilinear capsulorhexis in the anterior lens capsule, creates a crater of adequate depth in the cortex and inserts the human nucleus within this crater in the goat's capsular bag. The surgical wound is sutured, and the goat's eye is ready for training. Creating the capsulorhexis with precision and making the crater of adequate depth to snugly accommodate the human nucleus are the most important steps to prevent excessive wobbling of the nucleus while training.

Update on simulation-based surgical training and assessment in ophthalmology: a systematic review

TOPIC

This study reviews the evidence behind simulation-based surgical training of ophthalmologists to determine (1) the validity of the reported models and (2) the ability to transfer skills to the operating room.

CLINICAL RELEVANCE

Simulation-based training is established widely within ophthalmology, although it often lacks a scientific basis for implementation.

METHODS

We conducted a systematic review of trials involving simulation-based training or assessment of ophthalmic surgical skills among health professionals. The search included 5 databases (PubMed, EMBASE, PsycINFO, Cochrane Library, and Web of Science) and was completed on March 1, 2014. Overall, the included trials were divided into animal, cadaver, inanimate, and virtual-reality models. Risk of bias was assessed using the Cochrane Collaboration's tool. Validity evidence was evaluated using a modern validity framework (Messick's).

RESULTS

We screened 1368 reports for eligibility and included 118 trials. The most common surgery simulated was cataract surgery. Most validity trials investigated only 1 or 2 of 5 sources of validity (87%). Only 2 trials (48 participants) investigated transfer of skills to the operating room; 4 trials (65 participants) evaluated the effect of simulation-based training on patient-related outcomes. Because of heterogeneity of the studies, it was not possible to conduct a quantitative analysis.

CONCLUSIONS

The methodologic rigor of trials investigating simulation-based surgical training in ophthalmology is inadequate. To ensure effective implementation of training models, evidence-based knowledge of validity and efficacy is needed. We provide a useful tool for implementation and evaluation of research in simulation-based training.

[Design and validation of a simulator for training in continuous circular capsulotomy for phacoemulsification]

INTRODUCTION

To design and validate a simulator for learning and training in the capsulorhexis technique.

METHODS

The system consists of a methacrylate support inclined 15° for the surgeon's hand, an area of commercially available aluminum foil, and another one of similar characteristics, where the student performs the technique through some slots that are previously made in the support. In order to evaluate the feasibility of this simulator, data were collected from 65 ophthalmologists performing the technique during training activities. The ophthalmologists were randomly divided into one group of 30 specialists who start their learning on the eyes of an animal cadaver, and into another of 35 specialists who previously started with this simulator.

RESULTS

A simulator is developed for training in the capsulorhexis technique. The students from the simulator group achieved a reduction in the use of cadaver eyes, and a higher efficiency in correct capsulorhexis, unlike the group who started directly on the cadaver eyes.

CONCLUSIONS

This simulator is an innovation in training of the capsulorhexis technique as regards simplicity, cost, and reuse, as compared to other virtual simulators with more expensive computer equipment (CE) equipment that are more difficult to transport. It is an important step prior to the use of cadaver parts and experimental animals, decreasing the number of both, and therefore the teaching costs.