The clinical motivation is stark. Myopia has become one of the fastest-growing public health problems in the world, particularly among children and adolescents, and it is far more than a simple refractive error that glasses can fix. Progressive myopia involves excessive elongation of the eyeball, driven by a cascade that begins in the retina and ends in structural weakening of the sclera, the tough outer coat of the eye. Genetic susceptibility combines with environmental pressures such as prolonged near work, insufficient outdoor light exposure and abnormal retinal defocus to alter retinal neurotransmission, including dopamine signalling. These changes disturb the release of growth modulators such as retinoic acid, TGF-β and insulin-like growth factor, which in turn destabilize the balance of collagen synthesis and degradation in the sclera, mediated by matrix metalloproteinases and activated fibroblasts. The result is a thinner, softer sclera that deforms under normal intraocular pressure, stretching the eye axially and predisposing patients to retinal detachment, myopic macular degeneration and optic neuropathy.

SENGs attack this problem from a fundamentally different angle than conventional optical correction. The review divides the technology into two complementary classes. Piezoelectric nanogenerators, or PENGs, exploit materials such as zinc oxide nanowires, barium titanate nanoparticles and piezoelectric polymers like PVDF and its copolymer P(VDF-TrFE), in which mechanical deformation shifts internal charge distributions and creates a piezoelectric potential that drives current through an external circuit. Triboelectric nanogenerators, or TENGs, instead harvest charge generated when two materials with different electron affinities make contact and separate, an effect amplified by electrostatic induction. PENGs deliver moderate voltages with relatively higher current and suit implantable stimulation scenarios, while TENGs produce high open-circuit voltages at very low currents and excel in flexible wearable formats such as contact lenses and eyeglass-mounted sensors. Both operate comfortably within the mechanical regime of the eye, where a normal blink imposes roughly 2 to 5 kilopascals of pressure and forceful blinking can exceed 10 kilopascals.

The most striking preclinical demonstrations come from device prototypes that translate these physics into therapy. One electro-driven drug delivery system integrates barium titanate nanoparticles coated with atropine into an orthokeratology lens. When the wearer closes their eyes, eyelid pressure triggers the piezoelectric effect, generating transient microvoltages that are proposed to perturb the interfacial electrostatic equilibrium of the nanoparticles and promote atropine desorption. Release rates reach approximately 80 percent within 12 hours, with more release accumulating the longer the eyes remain closed, effectively synchronizing drug delivery with natural physiology. In guinea pig myopia models, this system achieved superior reversal of refractive error compared with atropine eye drops alone or combined lens-plus-drop regimens, increased choroidal blood flow velocity, and raised ocular tissue drug concentrations more than twenty-fold above blood levels without detectable systemic toxicity or ocular surface irritation.

Electrical stimulation itself may also remodel the diseased sclera. Inspired by the electrocyte discharge of electric eels, researchers developed a biomimetic piezoelectric patch called BPP@PVDF, made by spin-coating a piezoelectric PVDF membrane onto a bovine pericardium scaffold. Under physiological ocular deformation, the patch generates self-powered microcurrents that were associated with increased scleral fibroblast proliferation and type I collagen synthesis. In rabbit models of lens-induced myopia, eyes receiving the patch showed over 40 percent less axial elongation than sham-operated controls, along with denser and more regularly organized collagen fibers, 20 to 30 percent greater scleral tensile strength and no abnormalities in intraocular pressure, retina or cornea. The authors are careful to stress, however, that the intracellular signaling pathways connecting generated electricity to fibroblast activation remain incompletely defined, and long-term risks such as pathological fibrosis have not been systematically excluded.

Drug delivery to the back of the eye is a second major frontier. Intravitreal injections carry infection and retinal detachment risks, while non-invasive routes typically achieve delivery efficiencies below 5 percent. A wearable electric switch system comprising an electrically driven drug delivery lens and a flexible square-wave generator addresses this bottleneck by using electrical stimulation to transiently open junctions between retinal pigment epithelial cells, reducing resistance along the sclerochoroidal-retinal pathway. The system delivered immunoglobulin G with 14 percent efficiency, approaching the 16 percent achieved by intravitreal injection, enhanced macromolecular penetration three- to five-fold in rabbit eyes and worked across monoclonal antibodies, DNA origami and extracellular vesicles, with adjustable waveform parameters providing a controllable safety window.

The same physics also supports closed-loop sensing. Triboelectric sensors mounted on skin or eyeglasses can distinguish voluntary from involuntary blinks, decode eye movements in eight directions with micrometer spatial resolution, and monitor intraocular pressure with sensitivities of about 1.28 megahertz per millimeter of mercury. A wireless therapeutic contact lens platform integrating sensing, wireless communication and iontophoretic drug delivery has maintained stable intraocular pressure readings for up to two months in rabbits while delivering anti-glaucoma medication on demand. Combined with machine learning, such self-powered sensors could feed adaptive algorithms that adjust stimulation and drug-release parameters in real time, forming the basis of an intelligent feedback loop between the eye, external computation and therapy. The review notes that tellurium nanowire retinal nanoprostheses and the clinically validated PRIMA photovoltaic implant, while not energy harvesters themselves, provide powerful engineering templates for wireless neural interfacing and long-term biointegration that future SENG platforms can borrow.

Formidable challenges separate the laboratory from the clinic. The eye is a hostile environment for electronics: tear fluid shields surface charges, millions of blinks per year accelerate mechanical fatigue and delamination, and materials such as zinc oxide can dissolve and release cytotoxic ions, while lead-based piezoceramics pose obvious toxicity concerns that push designers toward lead-free alternatives like barium titanate and biodegradable polymers such as PLGA. A fundamental ‘power gap’ also persists, since blink-driven generators produce transient bursts rather than the continuous, tightly regulated currents needed for reliable neuromodulation, and patients with dry eye or impaired ocular motility generate too little biomechanical energy for dependable therapy. Hybrid devices that pair nanogenerators with miniature supercapacitors or thin-film batteries could buffer this variability. Regulatory pathways add another layer of complexity, because multifunctional platforms combining stimulation, drug delivery, biosensing and artificial intelligence will likely be classified as combination products requiring coordinated review of electrical safety, pharmacology, software reliability and cybersecurity. Pediatric use, the population that most needs myopia control, raises additional ethical and developmental concerns that will demand adult safety data first.

Even so, the trajectory is clear. Ophthalmic biomaterials are evolving from passive structural supports into dynamic, intelligent systems that sense, respond and adapt. By harvesting the eye’s own motion to power stimulation, drug release and continuous monitoring, self-generated electricity nanogenerators sketch a future in which myopia is actively managed as the progressive neurovascular disease it truly is, rather than passively corrected with lenses. If materials scientists, neuroscientists and clinicians can close the remaining gaps in energy stability, chronic biocompatibility and validated dosing, the review concludes, blinking may one day do far more than keep the eye wet. It could power the therapy that saves a child’s sight.

Subject of Research: Self-powered bioelectronic nanogenerators for myopia treatment and vision restoration

Article Title: Bioelectronic interfaces for restoring vision pathways

Article References: Wang, T., Zhao, B., Du, Y., Wu, S., Jiang, Y., Li, J., Miao, Y.-B., & Shi, Y. (2026). Bioelectronic interfaces for restoring vision pathways. Materials Today Bio, 40, Article 103652. https://doi.org/10.1016/j.mtbio.2026.103652

Image Credits: AI Generated

DOI: 10.1016/j.mtbio.2026.103652

Keywords: myopia, nanogenerators, triboelectric, piezoelectric, bioelectronics, drug delivery, retina, sclera, biomaterials, energy harvesting, contact lenses, neuromodulation