The Eye and Eye Diseases. STATS 19 SEM 2. 263057202. Talk 7. A.L. Yuille. Dept. Statistics. [email protected] Neural Prostheses. • Forms of Neural Prostheses already used. (Simpler than last week). CNN story. • Brain messages transmitted to nerve ends on pectoral muscles of the chest. • Thoughts cause chest muscles to contract, activate prosthetic arm. Mike May’s and Others • Project Prakash (light). Pawan Sinha (MIT). • Sinha studies how children’s brain adapt to years • • • of blindness followed by sight. Studies in India. Children have cataract surgery. Sinha “Merely treating the eyes is not enough. No one knows if the visual modality will reclaim areas in the brain that it lost to other senses during blindness”. Some patients commit suicide after recovered sight. Mike Mays and Others • India has the world’s largest population of blind children. 100,000 children. • 20% have Cataracts, which can be treated. • Poverty, inter-marriage to blind relatives, diet,… Mike May and Others. • Mondloch (McMaster). • Children with cataracts in the left-eye, can recognize faces after surgery. • Children with cataracts in the right-eye, cannot. • But probably too late if surgery happens 2 months after birth. Brain-imaging. • Brain imaging (FMRI) show that neural areas in • • • the brain devoted to vision can perform different functions for the blind. Vision area – Touch area. Increased activity in the Visual Cortex when blind subjects “read” by using Braille. Areas of the Visual Cortex get activated when blind patients remember words and do other verbal memory tasks. (Normal subjects use language areas). The Big Three Eye Diseases. • Cataracts • Glaucoma • Age-Related Macular Degeneration. The Eye • Anatomy . The Eye • Imaging and the Lens. The Eye • Photoreceptors: Rods and Cones. The Eye • Where things go wrong: • (I) The Lens (focuses light). • Lens structure can change. (Cell growth, protein • • changes). Cataracts. (II) Eye contains fluids. The pressure of the fluid can get high (insufficient drainage). This affects nerve cells. Glaucoma. (III) Retina failure. Age-Related Macular Degeneration. Cataracts. • With age, the Lens enlarges and the protein structure changes (e.g. lens can go yellow). Most people over 65 have some cataracts. • Symptoms: Poor distance vision, blurred vision, frequent prescription changes, poor night vision, glare, halo around lights, double vision. Cataracts. • The Lens. Cataracts. • Risk Factors: • Age, Diabetes, Women/Men, Race, Developing countries near the Tropics, Hereditary, Smoking, Some Medications, Excessive sunlight. • Second sight: vision appears to get better, but then gets far worse. Cataracts • Surgery is Effective. (These days). • Glass is well-tolerated by the Eye (2nd World War). • Remove parts of Lens (by Microsurgery). • Implant plastic. • Outpatient: go home the same day. Glaucoma • Glaucoma “silent thief of vision”. • Very difficult to detect. Accounts for 12% new blind cases in the US each year. • Start by gradually losing peripheral vision. This causes irreversible damage. • Regular Eye exams. Diagnose pressure in the eyes. Glaucoma • Glaucoma is a collection of different eye • • • • problems. All raise the pressure of liquid inside the eye. The Eye is basically hollow, like a balloon. It contains fluid that helps keep its shape. New fluid comes in, old fluid is drained out. But sometimes the drain gets blocked – raises fluid pressure, damages the optic nerve (irreversible). Glaucoma. Glaucoma • Draining. Glaucoma • Recall, the image is formed by the Rods and • • • Cones on the retina. These send nerve impulses to the brain via the Optic Nerve. The Optic Nerve starts at the Optic Disk. High fluid pressure in the Eye damages the Optic Disk. Exact mechanism is unknown. Peripheral vision is often lost before patients are aware of it. Glaucoma • Optic Nerve. Glaucoma • Treatment. • Lower the fluid pressure. • Eye drops, drugs, lasers, surgery. • Risk factors: Age, Hereditary, Race (African Americans). Age-Related Macular Degeneration. • Least understood. • Ageing of the outermost layer of the Retina. • Progressive degenerate changes in the epithelium cells, photoreceptors (rods and cones). • Major cause of blindness in US, England, Canada. Age-Related Macular Degeneration. • Cells on retina. Age-Related Macular Degeneration. • Risk Factors. • Women/Men, Heredity, Blue eyes – particularly Caucasians, smoking, high blood pressure, sunlight. • Treatment is limited. Some forms respond to lasers, surgery,… General Health Care. • Diabetes – major cause of blindness among working people in US. • Increases risk for Cataracts and Glaucoma. But also damages the retina directly. • Main risk factor for Diabetes – high blood sugar. General Health • High-Blood Pressure (Hypertension). Damages the blood arteries in the retina. • AIDS/HIV. Affects the immune system. Microorganisms CMV (Cytomegalovirus). • CMV attacks the retina of about 30% people with AIDS. Destroys tissue, causes bleeding, retinal detachment. Alan Scott and Botox • Botox was developed by an Eye Surgeon – Alan Scott. • It is used to relax eye muscles and allow eyes to track objects. • He sold the idea to a company for development. Later, the company realized that Botox could be used for cosmetics. Traditional Low-Vision Devices. • Low tech. • Hand-held magnifiers. • Telescopes. Summary • Review of the Eye. • Three Major Eye Diseases: Cataracts, Glaucoma, Age-Related Macular Degeneration. • First two treatable, if Glaucoma detected early enough. • Major advances in treatment.