10
Demarcation of Lens
For demarcation of a spherical lens, rotate the diopter measuring handwheel to focus the lines of
the (3) marker reticule clearly. Lightly move the lens to find the right optical center. Make three-
point printing marks with the printer.
For demarcation of the axis of a sphero-cylindrical lens, rotate the astigmatism axis measuring
handwheel to the required angle. Then rotate the diopter measuring handwheel while turning the
lens to focus the cylindrical marking lines clearly. Lightly move the lens to find the right optical
center. Make three-point printing marks with the printer.
For demarcation prismatic lens base, rotate the astigmatism axis measuring handwheel to the
required angle. Then rotate the diopter measuring handwheel to focus the lines of the (3) marker
reticule clearly. Lightly turn the prism lens so that the middle of the three green marking lines
passes through the center of the (8) eyepiece reticule. Make printing point marks by the use of
the printer.
MAINTENANCE
Do not dismantle the lensometer, as the accuracy will be compromised.
Store the lensometer in a dry, cool, indoor place in order to assure precise working condition.
Prevent the instrument from severe vibration or impact in order to avoid damage or loosening parts.
When changing the bulb, make sure the bulb is cool before touching.
Always keep the instrument clean. Do not touch the surfaces of the optical parts. Dust shall be cleaned
with an absorbent cotton-tipped applicator dipped with a mixture of ethanol and ether.
After each use, clean the instrument and cover it with a dust shield.
COMMON TROUBLE SHOOTING
Problem Reason
Solution
Bulb will not light up.
Mains are not connected.
Connect with the mains.
Cannot see eyepiece reticule when
adjusting the eyepiece readings.
Observer has too much
uncorrected refractive error.
Wear a refractive correction
when using the lensometer.
Green marking image cannot be
seen.
Bulb cannot be lighted or
Dust shield is still on.
Connect with mains or
Take off dust shield.
Green marking image
cannot be seen clearly.
Dust accumulates
on optical lens.
Clean it using cotton
dipped in cleaning solution.
Deviation of the center
of the green marking image.
Lock screws are loose.
Remove objective lens shield,
regulate three screws, lock them.
Translocation of the printing unit.
Loosening of limit
screw or loosening of
connecting screws.
Regulate limit screw & lock
or regulate connecting
screws & lock.
