The study proposed herein aims to accomplish the following: To determine the optimal exposure, gamma, contrast, and brightness corrections necessary to increase the perceived contrast of images by individuals affected by Retinitis Pigmentosa (RP) and to determine the optimal image overlay of input signals corrected at both high and low thresholds such that perceived contrast is maximized. Additionally, this study will develop an I/O system of minimal necessary size responsible for image processing following image acquisition from micro cameras that will output post-processed image data onto small, high resolution LCD/LED screens contained in a wearable binocular device similar to commercially available home theater glasses. Lastly, this study aims to expose a cohort of individuals affected with Retinitis Pigmentosa to a series of images, environments, and scenes typically difficult for RP affected individuals to observe and distinguish due to color similarities and decreased contrast and brightness; and subsequently assess the effectiveness of the wearable prosthesis based on the accuracy of object identification both with and without the device.
Vision loss affects millions of people worldwide. According to a 2002 survey by the World Health Organization (WHO), approximately 37 million individuals worldwide are totally blind, with 124 million having low vision. The WHO defines low vision and blindness as varying degrees of loss of visual acuity and visual field loss, relative to the better eye, with optimal correction. Blindness affects both genders, with individuals over 50 comprising 82% of the blind population. Causes of blindness vary, with approximately 60% being due to cataract and refractive errors which are treatable, while 15% are preventable such as bacterial infections of the eye. However, 15% of causes are difficult to treat, such as diabetic retinopathy and glaucomas, while 10% require additional research to develop treatments. Retinitis Pigmentosa (RP) is one of such currently untreatable causes of blindness. RP, along with Age Related Macular Degeneration (AMD) are amongst the more frequent causes of blindness in the developed world (Greenwald 2009), while RP itself is the leading cause of inherited blindness (Palanker 2004).
To understand the diverse causes of RP, a basic understanding of visual perception is required. Phototransduction (conversion of light to electrical signals) occurs first, which is initiated by two types of photoreceptors: rods and cones. These two types vary in their function as rods are primarily responsible for night vision and lack sensitivity to color while cones function in color vision. Light contacts these photoreceptors, and isomerizes a retinaldehydechromophore (retinal) which is bound to varying types of opsin proteins corresponding in their reactivity to different wavelengths of light. Upon absorption of a photon of light, the chromophore 11-cis-retinal is isomerized to the...