Retinitis Pigmentosa Essay -- Health, Diseases, Vision Loss, Blindnes

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. SIGNIFICANCE: 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... ...and RP1 (Ziviello 2005). More complex mechanisms for RP development have been suggested, such as mutations in carbonic anhydrases. Because photoreceptors have high metabolic needs, acidic metabolites resulting from aerobic and anaerobic respiration, such as lactic acid, are produced in large quantities by these cells, and as such necessitate removal to maintain pH homeostasis (Alvarez 2007). This is inherently troublesome due to the avascular nature of the retina. This function is instead performed by the choriocapilaris, and is reliant upon the activity of multiple enzymes such as carbonic anhydrase four (CA4). CA4 thereby helps to maintain pH homeostasis which is critical to the health and proper functioning of the photoreceptors, with CA4 mutations compromising this regulatory ability, resulting in photoreceptor degeneration, and subsequently RP (Alvarez 2007).