Flipped Classroom Case Learning vs Traditional Lecture-Based Learning in Medical School Ophthalmology Education: A Randomized Trial

PURPOSE

To address the problem of teaching noncore specialties, for which there is often limited teaching time and low student engagement, a flipped classroom case learning (FCCL) module was designed and implemented in a compulsory 5-day ophthalmology rotation for undergraduate medical students. The module consisted of a flipped classroom, online gamified clinical cases, and case-based learning.

METHOD

Final-year medical students in a 5-day ophthalmology rotation were randomized to the FCCL or a traditional lecture-based (TLB) module. The outcomes of subjective assessments (student-rated anonymous Likert scale questionnaire, scale 1 to 5, and course and teaching evaluation, scale 1 to 6) and objective assessments (end-of-rotation and post-MBChB multiple-choice questions, scale 0 to 60) were compared between the 2 groups.

RESULTS

Between May 2021 and June 2022, 216 students (108 in each group) completed the study. Compared with the TLB students, the students in the FCCL group rated various aspects of the course statistically significantly higher, including feeling more enthusiastic and engaged by the course and more encouraged to ask questions and participate in discussions (all P < .001). They also gave higher ratings for the instructional methods, course assignments, course outcomes, and course workload ( P < .001). They gave higher course and teaching evaluation scores to the tutors (5.7 ± 0.6 vs 5.0 ± 1.0, P < .001). The FCCL group scored higher than the TLB group on the end-of-rotation multiple-choice questions (53.6 ± 3.1 vs 51.8 ± 2.8, P < .001). When 32 FCCL students and 36 TLB students were reassessed approximately 20 weeks after the rotation, the FCCL group scored higher (40.3 ± 9.1) than the TLB group (34.3 ± 10.9, P = .018).

CONCLUSIONS

Applying the FCCL module in ophthalmology teaching enhanced medical students' satisfaction, examination performance, and knowledge retention. A similar model may be suitable for other specialties.

RIP3-mediated microglial necroptosis promotes neuroinflammation and neurodegeneration in the early stages of diabetic retinopathy

Diabetic retinopathy (DR) is a leading cause of blindness that poses significant public health concerns worldwide. Increasing evidence suggests that neuroinflammation plays a key role in the early stages of DR. Microglia, long-lived immune cells in the central nervous system, can become activated in response to pathological insults and contribute to retinal neuroinflammation. However, the molecular mechanisms of microglial activation during the early stages of DR are not fully understood. In this study, we used in vivo and in vitro assays to investigate the role of microglial activation in the early pathogenesis of DR. We found that activated microglia triggered an inflammatory cascade through a process called necroptosis, a newly discovered pathway of regulated cell death. In the diabetic retina, key components of the necroptotic machinery, including RIP1, RIP3, and MLKL, were highly expressed and mainly localized in activated microglia. Knockdown of RIP3 in DR mice reduced microglial necroptosis and decreased pro-inflammatory cytokines. Additionally, blocking necroptosis with the specific inhibitor GSK-872 improved retinal neuroinflammation and neurodegeneration, as well as visual function in diabetic mice. RIP3-mediated necroptosis was activated and contributed to inflammation in BV2 microglia under hyperglycaemic conditions. Our data demonstrate the importance of microglial necroptosis in retinal neuroinflammation related to diabetes and suggest that targeting necroptosis in microglia may be a promising therapeutic strategy for the early stages of DR.

Ocular symptoms as the initial clinical manifestations in patients with extraocular tumors

Background

Due to the variety of clinical presentation, some tumors may be concealed and easily misdiagnosed, leading to delays in management. We report a series of patients who initially presented to an Ophthalmic Clinic with ocular symptoms and were subsequently diagnosed with extraocular tumors.

Methods

Patients who presented to the ophthalmic outpatient clinic at the Joint Shantou International Eye Center with ocular symptoms between April 2013 and December 2019 and were subsequently diagnosed with intracranial or systemic tumors were reviewed retrospectively. Clinical data, including ocular symptoms and signs, ophthalmic and systemic imaging examinations, and the results of tumor biopsies were collected and analyzed.

Results

Twenty-three patients were included in this study, of which 16 were female (69.6%) and 7 were male (30.4%). Chief complaints at the first visit included visual loss (n=20), proptosis (n=2), and diplopia (n=1). Ocular examination revealed disc pallor (n=8) and swelling (n=3), choroidal mass with or without chorioretinal detachment (n=5), and proptosis (n=2). Visual field (VF) examination was performed in 11 patients of which hemianopia (n=4) and non-specific field loss (n=7) were noted. Brain CT or MRI, together with histopathological findings from surgical biopsies confirmed the diagnosis of the intracranial tumors in 18 cases, including pituitary adenoma (n=7), meningioma (n=2), oligodendroglioma (n=1), sellar tumor (n=1), suprachiasmatic arteriovenous aneurysm (n=1), orbital glioma (n=1), multiple intracranial tumors (n=1), and sphenoid ossifying fibroma (n=1). Nasopharyngeal carcinoma (NPC) (n=3) was diagnosed with brain MRI and nasal endoscopy. Five patients were confirmed as choroidal metastasis secondary to lung cancer (n=3), hepatoma (n=1), and breast cancer (n=1).

Conclusions

Patients with extraocular tumors may present initially to an ophthalmologist with ocular symptoms. It is important to identify and appropriately manage these patients to avoid unnecessary delays in future treatment.

Identification and characterization of a novel promoter variant in placental growth factor for neovascular age-related macular degeneration

PURPOSE

Intronic variants in the placental growth factor (PGF) gene have been associated with neovascular age-related macular degeneration (AMD). This study is to discover and characterize rare variants in the PGF gene for neovascular AMD.

METHODS

The promoter region, coding sequences and splicing regions of the PGF gene were sequenced in a Hong Kong southern Chinese cohort of 235 neovascular AMD patients and 435 controls. A detected 18 base-pair deletion variant in the promoter region of PGF was analyzed in a Shantou southern Chinese cohort of 189 neovascular AMD patients and 846 controls. The transcription activity of this disease-associated promoter variant was determined in human ARPE-19 cells by promoter-luciferase analysis.

RESULTS

A novel 18-base-pair deletion mutation in the promoter region of PGF was identified in 3 (1.28%) patients and 1 (0.23%) control subject (OR = 5.61; 95% CI 0.58-54.26) in the Hong Kong cohort, and in 2 (1.06%) patients and 2 (0.24%) controls (OR = 4.51; 95% CI: 0.63-32.25) in the Shantou cohort. In the combined southern Chinese sample, this deletion had a significant association with neovascular AMD (P = 0.026; OR = 5.08, 95% CI: 1.21-21.36). The 18-base-pair deletion was predicted to alter the transcription factor binding sites in the PGF promoter, and higher luciferase expression was detected in ARPE-19 cells transfected with the deletion variant plasmid than those transfected with wild type plasmid (P = 0.0002).

CONCLUSIONS

This study identified a rare, functional promoter variant in the PGF gene that increases PGF transcription activity and confers a 5-fold risk to neovascular AMD.

Measurement of evoked potentials after electrical stimulation of the human optic nerve

PURPOSE

To examine the visual evoked potentials (VEP) and electroretinograms (ERG) generated during electrical stimulation of the human optic nerve using the optic nerve visual prosthesis.

METHODS

Two volunteers blind from retinitis pigmentosa (RP) and with no light perception each received a chronically implanted optic nerve visual prosthesis. Cortical evoked potentials were recorded using 16 scalp electrodes, and antidromic ERGs were obtained using DTL electrodes while the optic nerve was electrically stimulated. The results were compared with flash and eye surface electrical stimulation results in normal-sighted control subjects.

RESULTS

The VEPs obtained in our two volunteers with implants had a waveshape similar to that obtained in normal-sighted volunteers during flash stimulation, but latency was reduced by approximately 25 ms. The VEPs recorded during surface eye stimulation are similar in both normal-sighted and RP volunteers. The VEPs were compared at sub- and supra-threshold stimulation strength and with different electrode configurations. Finally, the antidromic ERG recordings obtained in our implanted volunteers show a unique inner retinal potential generated by retrograde stimulation of the eye from the optic nerve.

CONCLUSIONS

Evoked potentials can be used to examine how a visual prosthesis generates visual sensations. This provides an objective means to investigate various aspects of the visual prostheses.

Creating a meaningful visual perception in blind volunteers by optic nerve stimulation

A blind volunteer, suffering from retinitis pigmentosa, has been chronically implanted with an optic nerve visual prosthesis. Vision rehabilitation with this volunteer has concentrated on the development of a stimulation strategy according to which video camera images are converted into stimulation pulses. The aim is to convey as much information as possible about the visual scene within the limits of the device's capabilities. Pattern recognition tasks were used to assess the effectiveness of the stimulation strategy. The results demonstrate how even a relatively basic algorithm can efficiently convey useful information regarding the visual scene. By increasing the number of phosphenes used in the algorithm, better performance is observed but a longer training period is required. After a learning period, the volunteer achieved a pattern recognition score of 85% at 54 s on average per pattern. After nine evaluation sessions, when using a stimulation strategy exploiting all available phosphenes, no saturation effect has yet been observed.