3D Printing in Eye Care

A novel 3D printing method for a notched eye plaque "dummy" for uveal melanoma brachytherapy

PURPOSE

Suture preplacement by the ocular oncology surgeon is a critical step before inserting a radioactive plaque for ocular melanoma brachytherapy. We report on a novel 3D-printing method to create a custom "dummy" plaque applicator for the 22 mm notched gold plaque using in-house 3D-printing.

METHODS

A computer-aided design (CAD) file was created replicating a heavily used gold plaque that no longer has a satisfactory "dummy" plaque. The file was exported as a 3D file (surface tessellation language, STL) and prepared using Formlabs' PreForm print software. The 3D-printed dummies were oriented on the printer to have no cups or supports on the surfaces that would come in contact with the patient's external sclera. The dummies were printed in FormLabs BioMed Clear V1 on a Formlabs Form-3 3D printer. Postprinting, the dummies were processed in isopropyl alcohol and cured according to manufacturer instructions. They were polished utilizing a rotary tool to improve transparency. Chemical and sterilization cycle tests were performed to ensure dummy integrity.

RESULTS

Four "dummy" plaques were printed. The 3D-printed "dummy" dimensions were verified to be within 0.5-mm of the notched plaque using digital calipers. The polishing process created acceptable light opacity for the eye plaque procedure in the operating room. No impactful discoloration or material change was observed during the chemical and sterilization cycle tests performed.

CONCLUSIONS

3D printing can produce custom eye plaque dummies using transparent, biocompatible, chemically inert materials suitable for human use. This capability introduces an additional layer of patient-specific hygienics.

A 3D Bioprinting Approach to Studying Retinal Müller Cells

Background/Objectives: Bioprinting is an innovative technology in tissue engineering, enabling the creation of complex biological structures. This study aims to develop a three-dimensional (3D) bioprinted model of Müller cells (MCs) to enhance our understanding of their physiological and pathological roles in the retina. Methods: We investigated two different hydrogels for their ability to support the viability and differentiation of rMC-1 cells, an immortalized retinal cell line. Using 3D bioprinting technology, we assessed cell viability, differentiation, and functional characteristics through various assays, including live/dead assays and western blot analysis. Results: The collagen-based hydrogel significantly improved the viability of rMC-1 cells and facilitated the formation of spheroid aggregates, more accurately mimicking in vivo conditions compared to traditional two-dimensional (2D) culture systems. Moreover, 3D bioprinted MCs exhibited reduced markers of gliosis and oxidative stress compared to 2D cultures. Molecular analysis revealed decreased expression of GFAP and phosphorylated ERK in the 3D setting, indicating a less stressed cellular phenotype. Conclusions: Our findings demonstrate that 3D bioprinting technologies provide a more predictive platform for studying the biology of retinal MCs, which can help in the development of targeted therapeutic strategies for retinal diseases.

Comprehensive review of the state-of-the-art in corneal 3D bioprinting, including regulatory aspects

The global shortage of corneal transplants has spurred an urgency in the quest for efficient treatments. This systematic review not only provides a concise overview of the current landscape of corneal morphology, physiology, diseases, and conventional treatments but crucially delves into the forefront of tissue engineering for corneal regeneration. Emphasizing cellular and acellular components, bioprinting techniques, and pertinent biological assays, it explores optimization strategies for manufacturing and cost-effectiveness. To bridge the gap between research and industrial production, the review outlines the essential regulatory strategy required in Europe, encompassing relevant directives, frameworks, and governing bodies. This comprehensive regulatory framework spans the entire process, from procuring initial components to marketing and subsequent product surveillance. In a pivotal shift towards the future, the review culminates by highlighting the latest advancements in this sector, particularly the integration of tissue therapy with artificial intelligence. This synergy promises substantial optimization of the overall process, paving the way for unprecedented breakthroughs in corneal regeneration. In essence, this review not only elucidates the current state of corneal treatments and tissue engineering but also outlines regulatory pathways and anticipates the transformative impact of artificial intelligence, providing a comprehensive guide for researchers, practitioners, and policymakers in the field.

Automatic data-driven design and 3D printing of custom ocular prostheses

Millions of people require custom ocular prostheses due to eye loss or congenital defects. The current fully manual manufacturing processes used by highly skilled ocularists are time-consuming with varying quality. Additive manufacturing technology has the potential to simplify the manufacture of ocular prosthetics, but existing approaches just replace to various degrees craftsmanship by manual digital design and still require substantial expertise and time. Here we present an automatic digital end-to-end process for producing custom ocular prostheses that uses image data from an anterior segment optical coherence tomography device and considers both shape and appearance. Our approach uses a statistical shape model to predict, based on incomplete surface information of the eye socket, a best fitting prosthesis shape. We use a colour characterized image of the healthy fellow eye to determine and procedurally generate the prosthesis's appearance that matches the fellow eye. The prosthesis is manufactured using a multi-material full-colour 3D printer and postprocessed to satisfy regulatory compliance. We demonstrate the effectiveness of our approach by presenting results for 10 clinic patients who received a 3D printed prosthesis. Compared to a current manual process, our approach requires five times less labour of the ocularist and produces reproducible output.

Surgical Medical Education via 3D Bioprinting: Modular System for Endovascular Training

There is currently a shift in surgical training from traditional methods to simulation-based approaches, recognizing the necessity of more effective and controlled learning environments. This study introduces a completely new 3D-printed modular system for endovascular surgery training (M-SET), developed to allow various difficulty levels. Its design was based on computed tomography angiographies from real patient data with femoro-popliteal lesions. The study aimed to explore the integration of simulation training via a 3D model into the surgical training curriculum and its effect on their performance. Our preliminary study included 12 volunteer trainees randomized 1:1 into the standard simulation (SS) group (3 stepwise difficulty training sessions) and the random simulation (RS) group (random difficulty of the M-SET). A senior surgeon evaluated and timed the final training session. Feedback reports were assessed through the Student Satisfaction and Self-Confidence in Learning Scale. The SS group completed the training sessions in about half time (23.13 ± 9.2 min vs. 44.6 ± 12.8 min). Trainees expressed high satisfaction with the training program supported by the M-SET. Our 3D-printed modular training model meets the current need for new endovascular training approaches, offering a customizable, accessible, and effective simulation-based educational program with the aim of reducing the time required to reach a high level of practical skills.

Fractal Phototherapy in Maximizing Retina and Brain Plasticity

The neuroplasticity potential is reduced with aging and impairs during neurodegenerative diseases and brain and visual system injuries. This limits the brain's capacity to repair the structure and dynamics of its activity after lesions. Maximization of neuroplasticity is necessary to provide the maximal CNS response to therapeutic intervention and adaptive reorganization of neuronal networks in patients with degenerative pathology and traumatic injury to restore the functional activity of the brain and retina.Considering the fractal geometry and dynamics of the healthy brain and the loss of fractality in neurodegenerative pathology, we suggest that the application of self-similar visual signals with a fractal temporal structure in the stimulation therapy can reactivate the adaptive neuroplasticity and enhance the effectiveness of neurorehabilitation. This proposition was tested in the recent studies. Patients with glaucoma had a statistically significant positive effect of fractal photic therapy on light sensitivity and the perimetric MD index, which shows that methods of fractal stimulation can be a novel nonpharmacological approach to neuroprotective therapy and neurorehabilitation. In healthy rabbits, it was demonstrated that a long-term course of photostimulation with fractal signals does not harm the electroretinogram (ERG) and retina structure. Rabbits with modeled retinal atrophy showed better dynamics of the ERG restoration during daily stimulation therapy for a week in comparison with the controls. Positive changes in the retinal function can indirectly suggest the activation of its adaptive plasticity and the high potential of stimulation therapy with fractal visual stimuli in a nonpharmacological neurorehabilitation, which requires further study.

The Segment, Slice, and 3D Print (SS3DP) Workflow of 3D Printing Eye Anatomy for Clinicians: A Proof-of-Concept Study

3D printing is becoming increasingly important as time passes, with the latest technologies driving innovation in many fields, including ophthalmology. However, more is needed to know how clinicians can become innovators in their daily practice without needing expert engineering knowledge of the underlying technologies. We aimed to address that shortcoming by developing a pipeline clinicians can use to 3D print. This workflow was named SS3DP: Segment, Slice, and 3D Print. It was tested by fabricating a 3D-printed eyeball. In terms of the results of this work, we observed that the segmentation process was imperfect due to the difficulty of segmenting small structures. The learning curve was steep initially, but the technique improved the more time spent on the segmentation platform. No quantitative analysis was carried out. Innovation in medicine is stifled if its leading participants, clinicians, cannot engage with it due to a lack of knowledge.

Three-dimensional bioprinting in ophthalmic care

Three-dimensional (3D) bioprinting is widely used in ophthalmic clinic, including in diagnosis, surgery, prosthetics, medications, drug development and delivery, and medical education. Articles published in 2011-2022 into bioinks, printing technologies, and bioprinting applications in ophthalmology were reviewed and the strengths and limitations of bioprinting in ophthalmology highlighted. The review highlighted the trade-offs of printing technologies and bioinks in respect to, among others, material type cost, throughput, gelation technique, cell density, cell viability, resolution, and printing speed. There is already widespread ophthalmological application of bioprinting outside clinical settings, including in educational modelling, retinal imaging/visualization techniques and drug design/testing. In clinical settings, bioprinting has already found application in pre-operatory planning. Even so, the findings showed that even with its immense promise, actual translation to clinical applications remains distant, but relatively closer for the corneal (except stromal) tissues, epithelium, endothelium, and conjunctiva, than it was for the retina. This review similarly reflected on the critical on the technical, practical, ethical, and cost barrier to rapid progress of bioprinting in ophthalmology, including accessibility to the most sophisticated bioprinting technologies, choice, and suitability of bioinks, tissue viability and storage conditions. The extant research is encouraging, but more work is clearly required for the push towards clinical translation of research.

Recent Advances of Ocular Drug Delivery Systems: Prominence of Ocular Implants for Chronic Eye Diseases

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

Innovation Process for Optical Face Scanner Used to Customize 3D Printed Spectacles

Many people for different reasons end up wearing glasses to correct their vision. From time immemorial, there has been an unquestionable ability to associate people with glasses. Designing the glasses according to the physiognomy of each person opens a new path for a completely new optical experience. The frames are designed to fit perfectly on the face, are comfortable on the nose, and are positioned at an optimal distance from the cheeks and eyelashes. Three-dimensional printing technology offers the possibility to customize any form of glasses at a low cost with average quality. In this type of technology, the printer receives a digitized model of the spectacle frame (usually in STL file format) that must meet the parameters related to the wearer’s anatomy. Therefore, this paper presents an innovative process, an optical method used to scan the wearer’s face to design a parameterized design of the spectacle frames. The procedure has a measurement phase for quantifying the anatomical features of the wearer’s face, a para-metric design phase of the glasses for adjusting the design parameters according to the anatomical characteristics, and a manufacturing phase in which the custom eyeglass frame will be manufactured using 3D printing technology. The aim of this study was to create an innovative process that could be tested as an educational 3D printing system that could be used by undergraduate students (studying under an optometry program), a process that would begin at optometric prescription stage and can be used in the educational laboratory of the Department of Mechatronics and Precision Mechanics from the Politehnica University of Bucharest. Using this method we obtained a custom spectacle frame that can be prototyped using 3D printing. The 3D-printed polylactic acid (PLA) frames are lightweight, flexible, durable, and the innovative photogrammetry process gives designers the ability to create custom designs that cannot be created with traditional manufacturing techniques.

The Role of Technology in Ophthalmic Surgical Education During COVID-19

Purpose of Review

To describe the effect of COVID-19 on ophthalmic training programs and to review the various roles of technology in ophthalmology surgical education including virtual platforms, novel remote learning curricula, and the use of surgical simulators.

Recent Findings

COVID-19 caused significant disruption to in-person clinical and surgical patient encounters. Ophthalmology trainees worldwide faced surgical training challenges due to social distancing restrictions, trainee redeployment, and reduction in surgical case volume. Virtual platforms, such as Zoom and Microsoft Teams, were widely used during the pandemic to conduct remote teaching sessions. Novel virtual wet lab and dry lab curricula were developed. Training programs found utility in virtual reality surgical simulators, such as the Eyesi, to substitute experience lost from live patient surgical cases.

Summary

Although several of these described technologies were incorporated into ophthalmology surgical training programs prior to COVID-19, the pandemic highlighted the importance of developing a formal surgical curriculum that can be delivered virtually. Novel telementoring, collaboration between training institutions, and hybrid formats of didactic and practical training sessions should be continued. Future research should investigate the utility of augmented reality and artificial intelligence for trainee learning.