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Visual Field Examinations

Visual Field Examinations. Week 3 Visual Pathway and Visual field defects. 4 major visual pathway zones. Monocular retinal zone Nerve fiber/optic nerve zone Binocular chiasmal zone Post chiasmal zone. Monocular retinal zone. Retinal layer.

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Visual Field Examinations

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  1. Visual Field Examinations • Week 3 • Visual Pathway and Visual field defects

  2. 4 major visual pathway zones • Monocular retinal zone • Nerve fiber/optic nerve zone • Binocular chiasmal zone • Post chiasmal zone

  3. Monocular retinal zone

  4. Retinal layer • Field defects are found opposite in the VF to the location of the damages in the eye.

  5. Retinal layer Retinal detachment Visual field

  6. Sub retinal layer • Choroidal lesions care caused by tumors, inflammations, infection, or fluid leaks. • This type of damage does not respect the horizontal or vertical meridian.

  7. Sub retinal layer Epi retinal membrane tear with bleeding hamangioblastoma

  8. Rods and cones • Damage may be caused by toxicity, inflammation, infections or heredity.

  9. Retinitis pigmentosa • A diffuse pattern of field loss ( rod damage) forming a ring a variable scotomas that will expand outward toward the periphery and inward toward the fovea until blindness results.

  10. Macular pathology • Damage to cone receptors causing damage to the central 5 degrees. • Decreased color and VA will result.

  11. Monocular retinal zoneCharacteristics • Retinal layer • Subretinal layer • Rods and cones • Retinitis pigmentosa • Macular pathology • All defects will be monocular. • Most pathology will be visible with a scope. • Lesions temporal to the fovea will present nasal on VF. • Lesions can cross all meridians. • Central scotomas will cause abnormal VA and color vision.

  12. Nerve fiber layer/optic nerve region zones • Nerve fiber layer. • Most common cause is glaucoma. Also may be caused by trauma, blood vessel occlusions, infections, inflammations and tumors

  13. Papilledema • (swelling of the disc) • Produces a field loss by pushing the surrounding retina out from the disc creating an enlarged blind spot. • It will present more concentric than an enlarged blind spot caused by glaucoma.

  14. Nerve fiber defect patterns • Macular and papillomacular defects create central or ceccocentral scotomas

  15. Bjerrum Defects • Bjerrum area of nerve fiber layer. • 15 degrees off fixation. • Defect in this area will cause an arcing VF loss opposite of the damage. • Will start small and increase in size over time.

  16. Nerve fiber layer/optic nerve region characteristics • Nerve fiber layer • Optic nerve (papilledema) • Nerve fiber pattern defects • Bjerrum area defects • All defects are monocular. • Defect will point to the disc since the nerve fibers are traveling toward this point. • All pathology will be visible with a scope

  17. Nerve fiber/optic nerve region Glaucomatous defects Damage to nerve fiber layer will show on VF.

  18. Glaucoma Temporal wedge Nasal step

  19. Nerve fiber/optic nerve region Optic nerve central scotoma Visual field

  20. Optic nerve zone

  21. Nerve fiber/ optic nerve region Characteristics • All will be monocular only effecting the damaged eye. • Damage to the nerve fiber layer will be caused by glaucoma. • The VF will show up opposite of the damaged area. • Specific areas of nerve fibers that have been damaged will respect the horizontal meridian and point in the direction of the disc. • Disc problems will be visible with a scope.

  22. Binocular Chiasmal Zone

  23. Bi temporal VF loss characteristics Binocular chiasmal zone • Caused by pituitary tumors or swelling, • Always bi temporal. • Not visible with a scope. • CT scan or MRI needed to show defect. • Bilateral hemianopia (temporal). • Will respect vertical meridian. • Will start small and gradually increase in size.

  24. Post chiasmal zone

  25. Post chiasmal zone Lateral geniculate body Optic Radiations

  26. Post chiasmal zone • Not visible with a scope. • Problem will be visible with CT or MRI scan. • Homonymous defect will always be present. (Same side) • Will start out small and gradually get larger. • Will be hemianopic and will respect the vertical meridian.

  27. Let’s see what you learned! • Follow the pathway- • Page 22 in your text. • What is this problem?

  28. What is the problem here?

  29. What’s the problem here?

  30. Last two, what’s wrong?

  31. Great job! See you next week for GoldmannPerimetry lecture.

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