Using a Lensmeter

Measuring the sphere and cylinder in glasses using a lensmeter is a crucial step in obtaining the correct prescription. It is crucial to ensure that the lensmeter is calibrated correctly to obtain accurate measurements. Additionally, keep the lenses clean and free from smudges or dirt to avoid any inaccuracies.

To measure the distance portion, place the glasses with temple pieces facing away from you on the lensmeter and move them until the mires are centered in the target. To measure the sphere power and the axis of cylinder, rotate the drum until the narrow lines are in focus while simultaneously rotating the axis until the narrow lines are straight. Note down the spherical power and axis. To measure the cylindrical power in plus cylinder, rotate the drum towards you until the thick lines are in focus. The difference between the two readings is the cylindrical power.

To measure the add power, flip the glasses so that the temple pieces are facing you. Rotate the dial towards you to get the thick lines in focus again, and note down the difference in diopters.

In conclusion, measuring the sphere and cylinder in glasses using a lensmeter requires careful attention to detail. By following the steps mentioned above, optometrists and opticians can accurately measure the prescription of eyeglasses and provide patients with the correct prescription for clear vision.