Macular Function Surveillance Revisited


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Presentation on the use of newer technologies to assist patients with macular degeneration with monitoring their vision at home

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Macular Function Surveillance Revisited

  1. 1. Macular Function Surveillance Revisited Rick Trevino, OD VA Outpatient Clinic Evansville, IN
  2. 2. Macular Function Surveillance <ul><li>Earlier intervention improves outcome </li></ul><ul><ul><li>Argon Laser </li></ul></ul><ul><ul><li>Photodynamic Therapy </li></ul></ul><ul><ul><li>Anti-VEGF </li></ul></ul><ul><li>Home surveillance of macular function can result in earlier detection of the symptoms of CNV </li></ul><ul><li>More effective in younger patients </li></ul>
  3. 3. Macular Function Surveillance <ul><li>Richard Förster (1862) </li></ul><ul><li>Marc Amsler (1953) </li></ul><ul><li>Ted Schlaegel (1968) </li></ul><ul><li>MPS (1983) </li></ul><ul><li>Entoptic Perimetry (2000) </li></ul><ul><li>Hyperacuity Perimetry (2003) </li></ul><ul><li>Computerized Amsler Grid (2004) </li></ul>
  4. 4. Disadvantages of Amsler Grid <ul><li>Low Sensitivity </li></ul><ul><ul><li>50% of scotomas missed </li></ul></ul><ul><ul><li>Only 30% of pts on Amsler surveillance that develop CNV detected their lesion using the grid (Zaidi, et al. Eye. 2004;18:503.) </li></ul></ul><ul><li>Completion Phenomena </li></ul><ul><ul><li>Perceptual filling-in of defects </li></ul></ul><ul><li>Eccentric Fixation </li></ul><ul><li>Poor Compliance (50%) </li></ul>
  5. 5. Improving the Amsler Grid <ul><li>Red Grid </li></ul><ul><li>Threshold Grid </li></ul><ul><ul><li>Cross-Polarizing Lenses </li></ul></ul><ul><ul><li>Low Contrast Cards </li></ul></ul><ul><ul><li>Computerized Amsler grid </li></ul></ul>
  6. 6. Non-Grid Surveillance Techniques <ul><li>Environmental Amsler </li></ul><ul><li>Entoptic Perimetry </li></ul><ul><li>Hyperacuity Perimetry </li></ul><ul><li>Internet-based Programs </li></ul>
  7. 7. Environmental Amsler <ul><li>Monocular inspection of straight lines in your surroundings for signs of distortion </li></ul><ul><ul><li>Door frames </li></ul></ul><ul><ul><li>Telephone poles </li></ul></ul><ul><ul><li>Ceiling or floor tiles </li></ul></ul><ul><ul><li>Crossword puzzles </li></ul></ul><ul><ul><li>Lines of text </li></ul></ul><ul><li>Encourage pts to develop the habit of monocularly assessing their vision </li></ul>
  8. 8. Entoptic Perimetry <ul><li>Random flickering of black and white dots on video display (TV “snow”) </li></ul><ul><li>Makes scotomas visible to the patient so they can be monitored for change </li></ul><ul><li>89% more sensitive than Amsler grid in detecting diabetic macular edema </li></ul><ul><li>Home surveillance with TV or computer </li></ul>
  9. 9. Entoptic Perimetry <ul><li>Advantages </li></ul><ul><ul><li>Simultaneous examination of the whole visual field </li></ul></ul><ul><ul><li>Subjective experience of visual field defects </li></ul></ul><ul><ul><li>Can be performed at home using a conventional TV </li></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>Low sensitivity for congenital or suprageniculate lesions (blind spot, most hemianopic defects) </li></ul></ul><ul><ul><li>Qualitative examination </li></ul></ul>
  10. 10. Hyperacuity Perimetry <ul><li>Utilizes Vernier acuity </li></ul><ul><li>More sensitive than Amsler grid in detecting late-stage vision defects in AMD </li></ul><ul><ul><li>Early AMD (PHP: 30%, AG: 30%) </li></ul></ul><ul><ul><li>Interm AMD (PHP: 46%, AG: 52%) </li></ul></ul><ul><ul><li>GA (PHP: 87%, AG: 67 %) </li></ul></ul><ul><ul><li>Wet AMD (PHP: 84%, AG: 80 %) </li></ul></ul><ul><li>Potentially able to differentiate pts with CNV </li></ul><ul><li>Home surveillance? </li></ul>
  11. 11. Hyperacuity Perimetry <ul><li>PreView preferential hyperacuity perimeter </li></ul><ul><ul><li>Macular perimetry using a dot deviation signal </li></ul></ul><ul><ul><li>Tests central 14 ˚ with 500 data points in 5 min </li></ul></ul><ul><ul><li>Preferential looking analysis: Quantitatively maps field defects using artificial distortions of the deviation signal </li></ul></ul><ul><ul><li>Algorithm analysis of the data is designed to detect the presence of CNV </li></ul></ul>
  12. 12. Hyperacuity Perimetry <ul><li>Advantages </li></ul><ul><ul><li>Quantitative </li></ul></ul><ul><ul><li>Positive predictive value </li></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>Requires expensive specialized equipment </li></ul></ul><ul><ul><li>Not suitable for home monitoring </li></ul></ul>
  13. 13. Internet-Based Programs <ul><li>Currently available: Downloadable Amsler </li></ul><ul><li>Great potential for newer generation tests </li></ul><ul><ul><li>Entoptic perimetry </li></ul></ul><ul><ul><li>Hyperacuity perimetry </li></ul></ul><ul><ul><li>Threshold Amsler </li></ul></ul>
  14. 14. Internet-Based Program <ul><li>Free web-based entoptic perimetry computer program </li></ul><ul><li>Record scotomas and alert patient to significant changes </li></ul><ul><li>Research study to compare defects on Amsler grid and entoptic perimetry in pts with AMD </li></ul>
  15. 15. Home Surveillance <ul><li>Amsler Grid </li></ul><ul><ul><li>Reinforce compliance </li></ul></ul><ul><li>Environmental Amsler </li></ul><ul><ul><li>Make it a habit to check monocular vision </li></ul></ul><ul><li>Television Entoptic Perimetry </li></ul><ul><ul><li>More sensitive than Amsler </li></ul></ul>
  16. 16. Thank You!