Deterioration of vision is inevitable to all humans. By the age of 45, the biological lens in our eyes starts to lose its elasticity thus producing refractive vision errors, and the eye cannot clearly focus the images. The result is blurred vision, which is sometimes so severe that it causes visual impairment. Three very common refractive errors are myopia (nearsightedness), hyperopia (farsightedness) and presbyopia (difficulty in reading at arm's length). In particular, presbyopia is an inevitable, universal age-related condition where the accommodative ability of the eye is lost permanently. Accommodation refers to the ability of the eye to increase its refractive power of the crystalline lens in order to focus near objects on the retina. In comparison to normal range of 7-10 diopters, it typically decreases to ~0.50 diopters by the age of 50. In 2005 over one billion people worldwide were estimated to suffer from presbyopia alone. Despite its ubiquity, the exact mechanism behind presbyopia remains unknown. Such refractive errors cannot be prevented, but they are treated with corrective glasses, contact lenses or refractive surgery. Eyeglasses are the most common inexpensive tools for correction of refractive vision errors. However, conventional corrective eyeglasses have a number of drawbacks; most importantly inability to fully restore the vision accommodation range of a normal eye. The principal goal of this work is the development of integrated sensing, actuating, control and data collection Smart Eyeglasses for adaptive correction of blurred vision caused by refractive errors. This cyber-physical opto-electro-mechanical system uses a combination of large-aperture fluidic lenses, ultralight actuators (aim 1) object distance and eye direction sensors (aim 2), and embedded control, communications and computing electronics to continuously produce full-field sharply focused images at any object range (aim 3). Furthermore, these glasses can record the observer's behavior, which can be utilized to predict prescription drift corrections and better eye medical treatment for patients and improvements in the observer environment. The testing of the smart eyeglasses will be performed with an instrumented phantom simulating visually impaired human subjects.
The key clinical implications of this project include the paradigm shift in the treatment for the inevitable deterioration in vision. The successful implementation could instantly impact their quality of life by enabling them to restore regular visions and maintain everyday life. We believe these new innovative vision correction tools could eventually help billions of sufferers constrained by limitations of current corrective technologies.
|Hasan, Nazmul; Banerjee, Aishwaryadev; Kim, Hanseup et al. (2017) Tunable-focus lens for adaptive eyeglasses. Opt Express 25:1221-1233|
|Hasan, Nazmul; Kim, Hanseup; Mastrangelo, Carlos H (2016) Large aperture tunable-focus liquid lens using shape memory alloy spring. Opt Express 24:13334-42|