Commentary: High fidelity and cost-effective cataract surgery training system: Need of the hour.

Cataract is the most common cause of avoidable blindness in the Indian population, particularly over the age of 50 years, rendering cataract surgery as one of the most commonly performed surgical procedures.[1] It is a complex surgical procedure that demands excellent hand-eye coordination. To achieve the best possible surgical outcomes, the residents/trainees must undergo rigorous and extensive training to evolve into dexterous surgeons. Cataract surgical training is an important constituent of any residency program across the globe. The technique, equipment, duration, and competencies can vary across the board. Many training programs emphasize on “observation,” while the others provide extensive “hands-on” training. Trainees in the developing world frequently face the lack of availability of consumables, poor quality of training equipment, inadequate trainers and their willingness to train, deficient patient pool, and high costs of equipment maintenance. However, looking into the magnitude of cataract-related blindness, it is imperative to train the residents adequately in surgical techniques in teaching/training institutes to achieve the goal of reducing the backlog of avoidable blindness in our country.

Traditional training is accomplished using the master-apprentice approach of supervised surgery on patients. However, this has been reported to be a cause of high incidence of complications, particularly in the initial part of the learning curve.[2] At present, when the accountability for suboptimal outcomes and patient satisfaction is of paramount importance, it is prudent to optimize resident surgical skills—outside the operating room—prior to operating on patients.[3]

The continuous curvilinear capsulorhexis (CCC) maneuver is a challenging task that warrants a considerable learning curve to master.[4] Multiple models have been developed to train the residents in this step before they can operate on patients. Simulation models and the associated fidelity is the extent to which the simulation environment matches the real-life patients and operating room set-up.[5] Using grapes for CCC training is an example of low-fidelity simulation.[6] High-fidelity simulations use eyes from goat, pig, rabbit, or human cadavers.[789] Virtual reality (VR) simulation is another example of a high-fidelity strategy.[210]

Grapes and tomatoes have been used for CCC training, being readily available and low-cost, and possess an elastic skin with mechanical tension; similar to that of an aging human lens capsule.[6] Given the scanty amount of research on this model, there is a need for more formal evaluation to establish its effectiveness in training the residents.

High-fidelity simulations utilizing biologic tissues such as porcine and human cadaver eyes in a wet-lab setting have been in use.[78] These approaches simulate the physical aspects of the CCC more closely. Chemical agents, such as formaldehyde solution, are used to reduce the elasticity of the porcine lens capsule, which then resembles the elasticity of the anterior capsule of the human crystalline lens. Low cost and ready availability of the chemical agents make this model easy to prepare. This also simulates the cataract in the human eye to a great degree of accuracy.[7] Autopsied eyes that are not suitable for organ donation could be obtained via eye banks and used for CCC training.[8] However, a dedicated wet-lab setting and an eye-bank facility are required for these models, which use biological tissues for training.

Virtual-reality (VR) simulation is another high-fidelity model for CCC training. It has the advantage of not relying on the supply of biological tissues and can be used multiple times. It simulates the surgical environment associated with human cataract surgery with high accuracy. Multiple studies have reported a good correlation between the performance of a VR simulator and real-life cataract surgery.[2] However, substantial purchase and maintenance costs hamper their wider accessibility. Future studies need to validate the VR simulators as educational tools to ensure that it is successfully incorporated into current systems of training in ophthalmology residency.[9]

The need for a dedicated wet lab set-up, limited supply of biological tissues, and high cost associated with VR simulation system prevents the development of adequate pre-clinical CCC training system at most ophthalmology training institutes in India. Dry-lab simulations have been reported, which use aluminum foil with Methacrylate support and provide medium fidelity for CCC training.[10] The use of such dry-lab models is limited compared to the wet-lab training models.[9] The device prepared by Dong J et al. can provide an excellent dry-lab model.[11] The presence of structures simulating cornea, anterior chamber, iris, use of tin-foil for anterior capsule, and foamed plastic for cortex should provide a near-natural environment for CCC training. The presence of an entry site for cystotome/capsulorrhexis forcep is an innovative idea that is usually absent in low-fidelity models. In our opinion, novice residents should practice CCC on this model before exposure to a wet-lab setting.

The absence of a control group to compare the difference in CCC learning time between residents practicing on this device and those who practiced on other modalities remains a major limitation of this model.[11] The outcome of this study can be further evaluated in a randomized controlled trial to demonstrate the transfer effects by showing whether the residents, who were trained using this model, achieved a higher percentage of satisfactory capsulorhexis in subsequent practice with animal eye models compared with those who began their training directly on animal eyes. Also, the study has its limitations in potential real-life surgical situations, like anterior capsular opacification, raised intra-lenticular pressure in hypermature cataract, corneal opacity, and shallow anterior chamber, which would predispose to a greater chance of capsulorhexis tear and extension. In conditions like corneal opacity, the shallow anterior chamber may be simulated with minor modifications in this device. Residents well versed with CCC in ideal surgical scenarios may practice the same by simulating complicated conditions.

Further improvisation of this model can be achieved by fixing it on an artificial structure, simulating the head and face, and can be used under an operating microscope; this model provides wrist support to the trainee for a more physiological surgical experience. In addition, improvising on the device to enable other steps of phacoemulsification would indeed be remarkable.