Effects of Transcorneal Electrostimulation on the Ciliary Muscle Morphology and Accommodation
Transcorneal electrical stimulation (TES) delivers weak electrical currents to the eye via a DTL electrode and is used both diagnostically—by determining phosphene thresholds that reflect retinal function—and therapeutically in retinal degenerative diseases such as retinitis pigmentosa. Prior work has shown that TES can slow disease progression, modulate retinal activity, and, in some applications, improve accommodative ability.
Until recently, however, it was unknown whether TES produces measurable anatomical changes in the ciliary muscle, the key effector of accommodation. A study from our own research group (Wagner et al., 2023) provides the first evidence that monocular TES induces a significant thickening of the ciliary muscle—not only in the stimulated eye, but also in the contralateral eye. Using OCT imaging in healthy young adults, the study demonstrated bilateral increases of approximately 25–31 μm in ciliary muscle thickness during TES, independent of the stimulated side.
This contralateral effect strongly suggests that TES influences central accommodation control pathways, rather than acting solely through local biomechanical or vascular mechanisms. Forward movement of the ciliary muscle apex was also observed—significant during contralateral TES—while refractive state and pupil size remained largely unchanged. A modest post‑TES decrease in intraocular pressure was recorded but is likely attributable to normal diurnal variation.
These findings provide the first direct morphological evidence that TES can modulate the accommodative apparatus via neuromodulatory pathways. This opens new perspectives for TES-based interventions targeting accommodation insufficiency, presbyopia, and potentially myopia control, and it advances our understanding of how electrical stimulation interacts with ocular and central visual mechanisms.
Publication
- Wagner S, Süer E, Sigdel B, Zrenner E & Strasser T (2023) Monocular transcorneal electrical stimulation induces ciliary muscle thickening in contralateral eye. Exp Eye Res 231: 109475