The document discusses lensometers, which are devices used to measure lenses. It defines a lensometer as an instrument used to measure lenses and describes two main types - manual and automatic. The manual lensometer is then explained in more detail, with a labeled diagram showing its basic optical structure and components, including an adjustable eyepiece, reticle, objective lens, Keplerian telescope, lens holders, illuminated target, light source, collimator, angle adjustment lever, power drum, and prism scale knob. It operates using the optical principle of the optometer developed by Badal.

1. Lensometer
Presented By Asif Faraz Nasir
M.optom

2. Definition
• Meaning
• 'Lenso'=lens
• 'Metry'=measurement of

3. Types
1.Manual,and
2.Automatic.

4. Manual lensometer
A simple lensmeter
cross sectional view.
1 – Adjustable eyepiece
2 – Reticle
3 – Objective lens
4 – Keplerian telescope
5 – Lens holder
6 – Unknown lens
7 – Standard lens
8 – Illuminated target
9 – Light source
10 – Collimator
11 – Angle adjustment
lever
12 – Power drum (+20
and -20 Diopters)
13 – Prism scale knob

5. Optics and basic structure
• also called conventional or manual lensmeter and operates on the
principle of optometer
• the optical principle of optometer developed by Badal is preferred
over the non badal principle.