The Eye and Eye Diseases. STATS 19 SEM 2. 263057202. Talk 7. A.L. Yuille. Dept. Statistics. email@example.com 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.