Phoropter; definition and explanation

1. Md. Nooruz Zaman
M.Optom
Faculty and consultant optometrist
Sankara College of Optometry

2.  Phoropter is an instrument designed to
provide convenient way of placing trial lenses
in front of patient to measure refractive state
of eye.
 Principle:
To determine the refractive status of the eye
and refractive correction

3.  Manual Refractors:
◦ Reichert Refractors
◦ Topcon Refractors
◦ Macro Refractors
◦ Bausch & Lomb Refractors
 Automatic Refractors:
◦ Tomey TAP 1000
◦ Digital Refractor Huvitz CDR-3100

4.  Basic Model of Refractors
 Parameters are adjusted using knobs and
dials.

6.  Both monocular and binocular PD is adjusted
using knobs on the top of the instrument.
 48 to 75mm by 1mm step

7.  Rotating the wheel or by tuning the knob.
 Rotating the downward for plus power and
upward for minus power.
 Range of power:
 0 to –19.00D in 0.25D step (0.12D step)
 0 to +16.75D in 0.25D step (0.12D step)

8. • Power and axis is accompanied by turning the
knobs.
• Changing Power by small centre knob and axis
by rotating.
• B&L green type refractor, small knob for axis
and larger one for the power
• available in plus or minus cylinder models.
• 0° a 180° ( Increments : 1° , 5° , 15° )
• 0 to –6.00D (-8.00D) in 0.25D step (0.12D
step).

9.  Refining cylindrical
power and axis.
 Equal powers with
opposite sign in the two
principal meridians.
 Knurled knob to flip the
lens
 ± 0.25D (± 0.37D and
± 0.50D as option)

10.  Risley prism / Rotatory prism
 Used for measuring phorias and fusional
vergence
 20 ∆D in 1 prism steps.

11. "0/0": Open Aperture
"R": Retinoscopic Lens: +1.50D standard
+2.00D option
"P": Polarizing Filter
"WMV/RMV": Maddox Rod, vertical: white(left) red
(right)
WMH/RMH": Maddox Rod, horizontal: white(left) red
(right)
+/-12 Strong spherical power
"GL": Green Lens (left)
"RL": Red Lens (right)
"PH": Pin hole
"10 L": 10 Diopter Prism Base In (Left)
"6 U": 6 Diopter Prism Base Up (Right)
"+_ 50": +_0.50D Fixed Cross Cylinder
"OC": Occluder

13.  Two disc like castings that house the lenses
 Instrument is mounted on a pole or stand
 A forehead rest is present to ensure that the
patient is correctly positioned.
 Large central knob – to adjust the
interpupilary distance

14.  Sphere and cylinder lenses on three disc
 Disc closest to eye – high power sphere
 Second disc - low power sphere
 Third disc - cylindrical lenses
 The axis is marked on the front surface are in
degrees 0 to 180 degrees with axis marking
in 5 degrees

15.  Occluders
 Maddox rods
 + 1.50D lens for retinoscopy
 Pinholes
 Prisms
 Reading card holder is also attached to front
of the phoropter.

16.  Amplitude of accommodation
 Relative accommodation
 Fusional vergence
 Various Binocular Balancing Test

17.  Useful data-link among mirror chart,
projector, refractor & lensmeter.
 Automatic data transmission & integrated
management of customer´s data.
 Refractometer´s data and lensmeter´s data
can be shared.
 Built-in printer in the Operation Panel .
 More test at less time.

20. • Less Time consuming
 More comfortable.
 No scratches or dust on the lenses.
 Additive errors can be reduced.
• Convenient way of Changing lenses and
accessories
• Same instrument for child.
• Special test can be carried out with the same
instrument.
• Axis of cylindrical correction can be read off
from the refractor head with greater accuracy.

21. • It hide the patients face
• Difficult to observe Head posture and eye
position,
• Difficult to do cover test
• Off axis cylindrical correction, in patients with
head tilt.
• Children below 4 yrs/ special child/ elderly
people.
• Frequent calibration is required.
• Expensive