MPMVA

• 1.occlude left eye
• 2. determine the unaided vision of the right eye
• 3. estimate the spherical lens, out this lens in the trial frame and add +1.00DS to the estimated spherical lens. you move the circle of least confusion away from the retina
• 4. the visual acuity should be reduced by about 4 lines and if it has not add more positive power to the sphere until four lines are lost to make the eye fogged
• 5. direct the patients attention to one letter on the lowest line they can read and ask if the letter is clearer with lens 1, then reduce the amount by 0.25DS and ask if 2 is clearer
• 7. continue to reduced the amount of fog in 0.25DS steps and stop when there is no improvement in vision
• • once you have calculated the best vision sphere need to determine the axis and amount
  • fan and block is internally illuminated with fan lines fixed at 10 degree intervals to indicate the axis setting of minus cylinder
  • Maddox v is used to determine the meridian if the posterior focal in the astigmatic line
• 1. once the best vision sphere is in place measure the visual acuity and estimate the cylinder using the table