An interactive method for teaching anatomy of the human eye for medical students in ophthalmology clinical rotations

Utility of pig head model as an oculoplastic wet lab surgical training tool

PURPOSE

To assess the utility of pig head model as an oculoplastic surgical training tool.

METHODS

Fresh pig head was availed for surgical workshop for entropion correction, eyelid margin repair, and evisceration with implant for oculoplastic surgery-naïve participants. Skill improvement, surgical understanding, and performance of the participants were evaluated both subjectively and objectively by trained oculoplastic surgeons. Subjective assessment was done by a standardized questionnaire based on Likert scale shared with the participants post training. Objective evaluation was done by the faculty based on a three-point scale and a competency-based surgical assessment rubric.

RESULTS

There were 18 surgery-naïve participants in the workshop which comprised ophthalmology residents and comprehensive ophthalmologists. About 88.88% of the participants were able to perform the lid margin and sub-tarsal dissection in entropion surgery. While performing lid tear repair, 94.44% were correctly able to identify the grey line and anterior and posterior lamellae. About 83.33% of the participants were able to place an implant in the scleral shell or intraconal space. About 83.33% of the participants noted that texture and tissue maneuvering were similar to the human eye while performing surgical steps. About 94.44% of the participants reported better understanding, development of skill and additional confidence after training. The median score on objective assessment was 3. The performance on real patients resulted in a median score of 4 for entropion correction.

CONCLUSION

Porcine orbital dissection is an available, affordable, and useful tool for oculoplastic surgical training. Training on porcine model can improve anatomical understanding, clinical judgement, and surgical efficiency in trainees.

The Decline of Basic Ophthalmology in General Medical Education: A Scoping Review and Recommended Potential Solutions

OBJECTIVE

This literature review aims to explore research and conceptual pieces on the state of ophthalmology education and suggest potential ways to address current challenges.

METHODS

A search was conducted in PubMed, ERIC, Web of Science, and Google Scholar with combinations of the following search terms: "ophthalmology education," "undergraduate medical education," "medical student," "United States," and "Canada." Eliminating irrelevant articles yielded 47 articles. Three were excluded because of region and focus, leaving 44. After examining the citations, we generated an additional 22 texts for review, totaling 66 articles.

RESULTS

Four primary themes were identified: (1) challenges to ophthalmological education in the U.S. and Canada, (2) potential remedies for optimizing ophthalmology curriculum, (3) technology in ophthalmology education, and (4) innovative ophthalmology teaching approaches. Major challenges included the lack of a standardized curriculum and inadequate clinical exposure and skills training. A number of remedies were proposed, such as standardizing curriculum and furthering faculty involvement, utilizing technology as time-effective learning aids, and employing innovative teaching approaches such as service learning.

CONCLUSION

In light of challenges in ophthalmology education, curriculum designers should consider Cognitive Load Theory (CLT) to assist students to remember meaningful exposures to ophthalmology knowledge and techniques. Based on CLT, we suggest two potential approaches to incorporating ophthalmology curriculum. The first is to embrace interdisciplinary collaborations and place ophthalmology knowledge in varied contexts to facilitate schema construction. The second is to incorporate ophthalmology diagnostics requirements into OSCEs and utilize simulation models for students to gradually increase the fidelity of tasks and devote cognitive resources fully to learning.

Exploring effectiveness in brain removal techniques: A comparison of approaches

Brain dissection is typically an important part of teaching neuroscience in health professional programs. This results in the need to effectively remove brains, which is often performed in a gross anatomy laboratory in the same curriculum. The aim of this study was to determine the most effective method of brain removal based on the time required for removal, difficulty of removal, and preservation of key brain structures for educational purposes. Six different dissectors performed each of the three calvaria removal approaches and three different spinal cord transection methods rating them for difficulty and tracking the time required. The combination of calvaria and brainstem approaches and the order of completion was randomized to control for fatigue and previous individual experience. After all brains were removed, each was evaluated by neuroscience faculty for utility in education contexts. The study found little difference between the individual approaches for both calvaria removal and spinal cord transection in regards to quality of outcome. The use of a circumferential cut only proved to be the most time-effective method for calvaria removal while a posterior cut between C1 and C2 was the most time-effective and least difficult method for brainstem release. There was no one technique that proved to be most beneficial across all three measures. However, different approaches resulted in a different combination of benefits across the time, difficulty, and outcome ratings that should be considered in light of the individual needs of any program or researcher.

Medical student competence in ophthalmology assessed using the Objective Standardized Clinical Examination

Purpose

To assess pre-clerkship and clerkship medical student performance in an ophthalmology Objective Standardized Clinical Examination (OSCE) station.

Methods

One hundred pre-clerkship medical students and 98 clerkship medical students were included in this study. The OSCE station consisted of a common ocular complaint - blurry vision with decreased visual acuity - and students were asked to take an appropriate history, provide two or three differential diagnoses to explain the symptoms, and perform a basic ophthalmic examination.

Results

Generally, clerks performed better than pre-clerks in the history taking (P < 0.01) and ophthalmic examination (P < 0.05) sections, with few specific exceptions. In the history-taking section, more pre-clerkship students asked about patient age and past medical history (P < 0.00001) and for the ophthalmic examination, more pre-clerkship students performed the anterior segment examination (P < 0.01). Interestingly, more pre-clerkship students were also able to provide two or three differential diagnoses (P < 0.05), specifically diabetic retinopathy (P < 0.00001) and hypertensive retinopathy (P < 0.00001).

Conclusion

The performance of both groups was generally satisfactory; however, many students in both groups had scores that were unsatisfactory. Notably, pre-clerks also outperformed clerks in certain areas, which emphasizes the importance of revisiting ophthalmology content through clerkship. Awareness of such knowledge can allow medical educators to incorporate focused programs into the curriculum.

Cadaver dissection for oculoplastic procedures: A beginner's guide

The purpose of this article is to form a basic guide for beginning the cadaver dissection training programs focused on oculoplastic surgical procedures. Ours was a collaborative study between the departments of Ophthalmology and Anatomy in a tertiary care teaching institute. We formed a step-wise approach to begin the cadaver dissection focused on the oculoplastic surgical procedures. The basics of cadaver procurement, processing, and preparation for dissections were described. The operative requirements of trainees, surgical handling of cadavers, and basic oculoplastic surgical steps were discussed. The types of embalming (cadaver preservation process) and steps have been described in detail. We have emphasized the preoperative discussion about the proposed dissections using standard teachings and skull models for easier understanding. Additional helping tools like soft embalming and injectable substances for better intra-dissection understanding (intra-arterial, intravenous and orbital injections) have been described. Post-dissection cadaver handing and soft-tissue disposal protocols have also been described. Overall, the cadaver dissections provide holistic surgical learning for the residents, specialty trainees, and practitioners. This article may act as a basic step-wise guide for starting the cadaver-based oculoplastics lab dissection in various institutes and workshops.

A Quantitative Analysis of Four Undergraduate Human Anatomy Laboratory Curricula: Approaches, Identified Structures, Concepts, and Thematic Emphases

Human anatomy is a foundational course thatserves diverse pre-professional health care majors. However, limited information is available on the teaching approaches, content, and thematic emphases of this course at the undergraduate level when compared with that of medical and other graduate schools. Herein, we document and quantitatively evaluate the laboratory curriculum of four undergraduate human anatomy courses in the USA. For each course, we assess the total number of structures (terms requiring identification during an exam), concepts (terms requiring an explanation), and clinical applications. To facilitate further assessments, we also compare the content distribution of each course with that recommended by the American Association of Clinical Anatomists (AACA). Two courses followed a regional approach emphasizing the use of human cadavers, while the other two followed a system-based approach and used plastic models and non-human cadaveric materials (e.g., cats and sheep). The total amount of information presented to students differed significantly among curricula. The majority of terms (65-88%) taught to students referred to the identification of anatomical structures whereas clinical applications were rare (< 1.3%). Courses using a regional approach expected students to learn as much as twice the number of terms than those following a system-based approach. Functions, innervations, origins, and insertions of muscles are only included in the curriculum of the courses following a regional approach. The proportion of terms devoted to each anatomical module in all curricula was significantly different from each other, as well as from that of AACA recommendation. We discuss these differences in the curriculum, the challenges and limitations inherent with each teaching approach, as well as in the teaching materials used among the curricula. These quantitative analyses aim to provide insightful information about the structure of the undergraduate human anatomy laboratory curriculum and may prove useful when redesigning a course.

Controlled non-invasive iontophoretic delivery of triamcinolone acetonide amino acid ester prodrugs into the posterior segment of the eye

This study investigated short duration transscleral iontophoretic delivery of four triamcinolone acetonide (TA) amino acid ester prodrugs (TA-AA) (alanine, Ala; arginine, Arg; isoleucine, Ile and lysine, Lys) using whole porcine eyes globes in vitro. Post-iontophoretic biodistribution of TA was quantified by UHPLC-MS/MS in the different ocular compartments (cornea, aqueous humor, sclera, ciliary body, choroid and retinal pigmented epithelium (RPE), neural retina and vitreous humor). Transscleral iontophoresis (3 mA/cm² for 10 min) increased total drug delivery of the TA-AA prodrugs by 14-30-fold as compared to passive diffusion. The TA-AA prodrugs had distinct biodistribution profiles - the penetration depth achieved was dependent on their physicochemical properties (e.g. lipophilicity for TA-Ile) and susceptibility to hydrolysis (e.g. TA-Arg). Intraocular drug distribution was also influenced by prodrug binding to melanin (TA-Lys). Interestingly, under conditions of equivalent charge (6 mA/cm² for 5 min vs. 1.5 mA/cm² for 20 min, i.e. 1.44 C respectively) the longer duration (20 min) at lower current density resulted in ∼6 times more TA delivery into the vitreous humor. Overall, the study provided further evidence of the potential of transscleral iontophoresis for the non-invasive treatment of posterior segment inflammatory diseases.

Impact of Chemical Structure on Conjunctival Drug Permeability: Adopting Porcine Conjunctiva and Cassette Dosing for Construction of In Silico Model

Conjunctiva occupies most of the ocular surface area, and conjunctival permeability affects ocular and systemic drug absorption of topical ocular medications. Therefore, the aim of this study was to obtain a computational in silico model for structure-based prediction of conjunctival drug permeability. This was done by employing cassette dosing and quantitative structure-property relationship (QSPR) approach. Permeability studies were performed ex vivo across fresh porcine conjunctiva and simultaneous dosing of a cassette mixture composed of 32 clinically relevant drug molecules with wide chemical space. The apparent permeability values were obtained using drug concentrations that were quantified with liquid chromatography tandem-mass spectrometry. The experimental data were utilized for building a QSPR model for conjunctival permeability predictions. The conjunctival permeability values presented a 17-fold range (0.63-10.74 × 10^-6 cm/s). The final QSPR had a Q² value of 0.62 and predicted the external test set with a mean fold error of 1.34. The polar surface area, hydrogen bond donor, and halogen ratio were the most relevant descriptors for defining conjunctival permeability. This work presents for the first time a predictive QSPR model of conjunctival drug permeability and a comprehensive description on conjunctival isolation from the porcine eye. The model can be used for developing new ocular drugs.

Imaging of Scleral Collagen Deformation Using Combined Confocal Raman Microspectroscopy and Polarized Light Microscopy Techniques

This work presents an optospectroscopic characterization technique for soft tissue microstructure using site-matched confocal Raman microspectroscopy and polarized light microscopy. Using the technique, the microstructure of soft tissue samples is directly observed by polarized light microscopy during loading while spatially correlated spectroscopic information is extracted from the same plane, verifying the orientation and arrangement of the collagen fibers. Results show the response and orientation of the collagen fiber arrangement in its native state as well as during tensile and compressive loadings in a porcine sclera model. An example is also given showing how the data can be used with a finite element program to estimate the strain in individual collagen fibers. The measurements demonstrate features that indicate microstructural reorganization and damage of the sclera’s collagen fiber arrangement under loading. The site-matched confocal Raman microspectroscopic characterization of the tissue provides a qualitative measure to relate the change in fibrillar arrangement with possible chemical damage to the collagen microstructure. Tests and analyses presented here can potentially be used to determine the stress-strain behavior, and fiber reorganization of the collagen microstructure in soft tissue during viscoelastic response.

Current integration of dissection in medical education in Australia and New Zealand: Challenges and successes

The reduced use of dissection associated with the introduction of integrated systems problem-based learning curricula, graduate-entry programs and medical school expansion is a frequent topic of discussion and debate in modern medical training. The purpose of this study was to investigate the impact of these changes to the medical education landscape, by looking at the current utilization and integration of dissection in medical schools, in Australia and New Zealand. A survey and an invitation to participate in an interview were distributed to all Australian Medical Council-accredited medical schools. Sixteen schools (76%) responded to the survey and five interviews (24%) were conducted. Dissection was a component of the medical program in 12 of the 16 schools surveyed. The opportunity for medical students to dissect human cadavers was found to be related to whether the medical school was established pre- or post-2000 (P = 0.003) but was not significantly associated to undergraduate- or graduate-entry (P = 0.64), program length (P = 0.59) or the number of commencing students (P = 0.07). The methods used for the delivery and integration of dissection varied between schools. Despite substantial changes to the delivery of anatomy in Australian and New Zealand medical schools, a variety of approaches have been adopted to ensure dissection remains an integral component of medical student education. Based on our findings, a number of recommendations were formulated to encourage the integration of dissection, regardless of the didactics of the program, to enhance the anatomical knowledge of students.

A porcine model: surgical anatomy of the orbit for maxillofacial surgery

Due to its similarity to humans, the pig has proven to be a suitable biomodel for both research purposes and for training medical professionals, particularly in surgical specializations. For example, new implant materials have been tested on pig jaws and pigs have also been used in the development of new surgical techniques. For optimizing the effectiveness of such research or training, detailed data on the anatomy of their particular features are needed. At present, however, only limited information related to surgical and imaging anatomy of the facial and orbital areas of the pig and its comparison to human structures from the experimental surgery point of view is available in the literature. The aim of this study was to obtain such data and to compare the morphological structures of the porcine and human orbital regions and to lay down the foundation for practical use in experimental surgery. Ten pig heads were examined using computed tomography (CT) and magnetic resonance imaging (MRI) and, subsequently, a dissection of the orbit was carried out. Attention was focused on the structure of the orbit (floor, rim and nerves) frequently affected by pathological processes in humans (such as trauma, infection or tumours) and which consequently are frequently the subject of maxillofacial surgery. The porcine orbit is suitable for use in experimental medicine. However, if used in experiments, its anatomical peculiarities must be taken into consideration. Our study presents a foundation of basic knowledge for researchers who plan to use the pig as a biomedical model to investigate alternative treatments in the head region.

3D printed reproductions of orbital dissections: a novel mode of visualising anatomy for trainees in ophthalmology or optometry

BACKGROUND

The teaching of human head, neck and orbital anatomy forms a critical part of undergraduate and postgraduate medical and allied health professional training, including optometry. While still largely grounded in cadaveric dissection, this method of instruction is constrained in some countries and regional areas by access to real human cadavers, costs of cadaver bequest programmes, health and safety of students and staff and the shortage of adequate time in modern curricula. Many candidates choosing a postgraduate pathway in ophthalmological training, such as those accepted into the Royal Colleges of Ophthalmology in the UK, Australia and New Zealand programmes and the American Academy of Ophthalmologists in the USA, are compelled as adult learners to revise or revisit human orbital anatomy, ocular anatomy and select areas of head and neck anatomy. These candidates are often then faced with the issue of accessing facilities with dissected human cadaveric material.

METHODS

In light of these difficulties, we developed a novel means of creating high-resolution reproductions of prosected human cadaver orbits suitable for education and training.

RESULTS

3D printed copies of cadaveric orbital dissections (superior, lateral and medial views) showing a range of anatomical features were created.

DISCUSSION

These 3D prints offer many advantages over plastinated specimens as they are suitable for rapid reproduction and as they are not human tissue they avoid cultural and ethical issues associated with viewing cadaver specimens. In addition, they are suitable for use in the office, home, laboratory or clinical setting in any part of the world for patient and doctor education.

[Technique for removing donor sclera by eyeball extrusion]

PURPOSE

To describe a surgery technique for removing donor sclera tissue after corneo-scleral button excision.

RESULTS

The extrusion technique is easy to perform. It allows the complete scleral extraction its total clean up to be performed, as well as making easier to isolate the retina and uveal tissue. This technique could have an important role in the anatomical and morphological study of ocular structures.

Porcine ophthalmology

Although there appears to have been an increase in literature about the anatomy and physiology of the pig eye because of an expansion in its use as a model for research, there has been little written about the development of veterinary medicine in the area. Pig eyes share many similarities with human eyes, having a holangiotic retinal vasculature, no tapetum, cone photoreceptors in the outer retina, and a similar scleral thickness, rendering them valuable in comparative research. It must not be forgotten, however, that pigs are intelligent sentient animals which use vision as an important sense. Thus, diseases such as congenital cataracts, which impede vision, are important from the perspective of pig welfare. In addition, ocular lesions in this species, as with many others, can be a significant sign of systemic disease.

Evaluation of a new disposable silicon limbal relaxing incision knife by experienced users

BACKGROUND

Previous research has suggested that the silicon BD Atomic Edge knife has superior performance characteristics when compared to a metal knife and performance similar to diamond knife when making various incisions. This study was designed to determine whether a silicon accurate depth knife has equivalent performance characteristics when compared to a diamond limbal relaxing incision (LRI) knife and superior performance characteristics when compared to a steel accurate depth knife when creating limbal relaxing incision.

METHODS

Sixty-five ophthalmic surgeons with limbal relaxing incision experience created limbal relaxing incisions in ex-vivo porcine eyes with silicon and steel accurate depth knives and diamond LRI knives. The ophthalmic surgeons rated multiple performance characteristics of the knives on Visual Analog Scales.

RESULTS

The observed differences between the silicon knife and diamond knife were found to be insignificant. The mean ratio between the performance of the silicon knife and the diamond knife was shown to be greater than 90% (with 95% confidence). The silicon knife's mean performance was significantly higher than the performance of the steel knife for all characteristics. (p-value < .05)

CONCLUSIONS

For experienced users, the silicon accurate depth knife was found to be equivalent in performance to the diamond LRI knife and superior to the steel accurate depth knife when making limbal relaxing incisions in ex vivo porcine eyes. Disposable silicon LRI knives may be an alternative to diamond LRI knives.