OPTOMETRIC EQUIPMENTS
IN REFRACTION ROOM
Presented by
T.Muthuramalingam
Contents
•
•
•
•
Torch
Retinoscope
Trial set
Trial frame
• RAF Ruler
• Prism Bar
• IPD scale
• Snellen’s near & distance
chart
• JCC
• Illuminated bulb
• Autorefractometer • Mirror
• PC
Torch
• Used to see the corneal
reflex, the ocular
movement, the
abnormality of ocular
surface
Retinoscope
•It is a hand-held
instrument that is used
to objectively determine
the refractive power of
the eye
•It has a light source & a
way to shine light into
patients eye & observe
its reflection from
patients retina
Trial Set
• Trial lenses
• Pinhole
• Occluder
• Stenopaic Slit
• Red & Green glass
• Maddox Rod
• Prism
Trial lenses
• Trial lenses are sets of lenses of
two types sphere and cylinder.
• To measure the refractive state of
the eye.
Occluder
• Is a opaque disc
• Used to take Vision uniocularly
Trial Frame
• Trial frame is an adjustable frame that is
used with trial lenses when measuring the
patients for spectacle lenses.
• The pupillary distance,lens height ,cylinder
axis can be set to accommodate the
patients size
• It consist of 4 case. Front case is for
cylindrical lens, back case for high myopic
lens, other for additional lens and Occluder
Pinhole
• Pinhole accessory consist
of an opaque disc with a Pinhole (PH)
• Optical function of Pinhole: Pinhole allows
the passage of central rays of light. This
permits the formation of clear image.
Uses of Pinhole:
If patient’s vision improves with pinhole,
patient is having uncorrected refractive error.
If patient’s vision is not improving then
patient may have any pathological defect or
neurological defect of the eye
Stenopic Slit
• The Stenopaic slit consists of a
rectangular aperture ranging from 0.5mm
to 1.0mm in width and up to 15mm in
length.
• Stenopaic slit reduce the size of blur circle
in the meridian at right angle to the slit,
yet allows blur circle size to be unchanged
in the meridian coincident with it
Uses of Stenopic Slit
• To find out astigmatic power and axis.
• To measure vertex distance.
Red & Green glass
• Red and green lenses are primarily
use before an eye to interrupt
fusion in the assessment of
binocularity. These are used for
worth four dot test, FRIEND test
and stereopsis.
Maddox Rod
• Maddox rod
consists of a
series of powerful
convex cylindrical
lenses, mounted
side by side in a
trial lens. The
glass of Maddox
rod is tinted red
Uses of Maddox Rod
•
•
•
•
Maddox rod is used in the diagnosis of
extra ocular muscle imbalance.
Maddox rod is placed in front of right
eye.
A distance white spot light source
viewed through both eye
Right eyes see red line at 900 to the
axis of Maddox rod, left eyes sees
spotlight.
Two eyes sees dissimilar images and
dissociated, allowing any muscle
imbalance to become manifest.
Prism
• Prism is a triangular geometrical figure
having two refracting surface meeting
at an apex joined by a base
• Used in treatment of diplopia and to
overcome the residual deviation in
squint.
• In trial set, Prisms are ranging from
1/2prism diopter to 12prism diopter
JCC
• A sphero-cylinder lens
• The power of the cylinder is twice the
power of the sphere and of the opposite
sign.
• Used to refine power and axis of
cylindrical power
Snellen's Chart
• Used to assess Vision.
• Can be used at 3mtr &
6mtr.
• Also used for near vision
assessment
Autorefractometer
• Autorefractometer is an optical
instrument that can automatically
determine the refractive measurement
of the eye.
• It has a chin rest, forehead rest,
viewing screen for the observer to
monitor fixation.
Prism Bar
• Prism bar are sets of
plastic prisms that are
attached to each other in
ascending order of power.
• Prism bar can be horizontal
and vertical
• Used to measure the
vertical and horizontal
amplitude of fusion of
patients
RAF Ruler
• Royal Air force Ruler
• Used to measure the
amplitude of
accommodation,
near and far point of
accommodation,
near point of
convergence
IPD Scale & Pupillometer
• Used to measure the
Inter Pupillary
Distance uniocularly
and binocularly
Other accessories
• Illuminated bulb: it is kept just above
and behind the patient’s head to
provide the illumination for near vision
assessment
• Mirror: it is used for maintaining the
6m distance placed at 3m
• PC: A palmtop computer. to provide the
printed prescription of glasses and to
collect the data of glass prescription
prescribed per day