Certified Ophthalmic Technician (COT) Practice Test 2025 - Free COT Practice Questions and Study Guide

In lensometry, the goal is to determine the power of a lens by focusing the lines generated by a lensometer. The readings of the lines provide critical information about the lens's optical characteristics.

When the single lines come into focus at plano (0.00 D), this indicates that there is no power in one meridian. The plano reading suggests that one axis of the lens does not change the direction of light.

The triple lines coming into focus at -2.00 indicate the power in the second meridian; this is where the light is being bent to focus at a specific point established by the -2.00 D reading. In lensometry, when analyzing lenses, it is essential to include both components: the plano (0.00) and the -2.00 D at the 90-degree axis.

Combining these findings leads to the conclusion that the lens can be described in two parts: one meridian is plano, and the second meridian carries a power of -2.00 with an axis at 90 degrees. Hence, the correct way to express this in standard notation of lens power is PLANO-2.00x90, which accurately reflects the measurements taken from the lensometer.

Thus, the