The contact lens is a suitable wearable smart device for either sensing ocular physicochemical parameters
1–4 (intraocular pressure, temperature, biomolecules in tears) or delivering drugs for the treatment of various ocular diseases.
5 Elevated intraocular pressure (IOP) is a major risk factor for the development and/or progression of glaucoma,
6,7 and timely drug delivery is necessary to prevent retinal tissue damage by reducing IOP. Contact lens-based continuous monitoring of IOP is necessary for successful treatment of glaucoma because patients can have a wide variation of IOP across the circadian pattern.
8 Current contact lens-based electromechanical measurements of IOP require integration of power batteries and strain-gauge circuits, including signal transmission, in addition to external receivers, resulting in either expensive devices or limited accessible places for successful data acquisition.
9 A study of optical monitoring of IOP used moiré patterns generated from two overlapping contact lenses,
10 which was inconvenient for the wearers due to the thickness of the two lenses.
Compared to eye drops, which have a low delivery efficiency, contact lens-based drug delivery is a more effective method to deliver drugs by direct contact with the cornea. Stimulus-triggered drug release from contact lenses is an emerging technique to deliver therapeutic payloads on demand while preventing drug loss due to premature elution from the lenses during shipping and storage.
11,12 It is desirable to investigate drug-eluting effects using an in situ acute glaucoma model that allows quick evaluation of the effective therapeutic doses, especially considering the poor correlation of in vitro drug release studies with in vivo drug efficacy. In this study, we present a feasibility study of optical IOP measurement by generating changes in a moiré pattern superimposed on contact lenses with virtual reference images and body temperature-triggered, drug-eluting contact lenses in a glaucoma rabbit model.