INSTRUMENTS USED
IN THE PRACTICE
OF OPTOMETRY
A report presented to
Dra. Deneb Daymon-Surban and
to the Department of Optometry,
Southwestern University PHINMA,
Cebu City
In partial fulfillment
of the requirements of the subject
OPT 001: Introduction and History of Optometry
August 2018
MEMBERS
Reporters
Anguluan, Kevin Cliff
Marcial, Art James E.
Compilation and Editing
Sapio, Rochyne Daphne Kate
Researchers
Albuera, Ralph Emirson
Almaras, Azariah Marie
Borenaga, Francis Renel B.
Dalope, Camila
Flores, Benito A. IV
Gacutan, Liyeen Vei S.
Gusarin, Viama A.
Malade, Carlo O.
Manuel, Marietta
Pagar, J.Rhex B.
Salamida, Nicole Audrey
Sarausa, Muffy Joy
Tuico, Cyrene Jayne M.
Uy, John Richard C.
2
Abstract
According to Republic Act 8050, otherwise known as the Revised Optometry Law
of 1995,
Optometry is
analyzing
art
and science of
ocular
functions,
ophthalmic
lenses,
accessories
and
appliances
training,
diagnostic
and
devices,
orthoptics,
prescribing
prisms,
solutions,
contact
low
agents
and
aids,
ocular
prosthetics,
(DPA),
dispensing
lenses
vision
conducting
installing
pharmaceutical
examining the human eye,
and
and
and
exercises,
using
their
similar
vision
authorized
other
preventive
or corrective measures or procedures for the aid,
correction,
rehabilitation or relief of the human eye, or to attain maximum
vision and comfort.
In line with this definition, optometrists and ophthalmologists need special optical
instruments or equipment to conduct ocular check-ups, correct refractive errors, examine
the human eye, and to determine possible underlying disease in the errors present in the
patients’ eye.
Some of the most common instruments used in the practice are defined in this
report such as the phoropter, trial case, and Snellen’s chart, among others. The functions
of the aforementioned are thoroughly discussed and explain in this manuscript and further
more on the actual presentation.
Moreover, this report done to inform and disseminate information to fellow
optometry students the importance of knowing what are the ‘this’ and ‘that’ in our course,
most especially since precision and accuracy are two of the highest qualifications in the
field of Optometry.
3
TABLE OF CONTENTS
Page
Cover Page
1
Group Members
2
Abstract
3
Table of Contents
4
INSTRUMENTS USED IN
THE PRACTICE OF OPTOMETRY
Automatic Edger
6
Automatic Refractometer
6
Balance Board
7
Binocular Indirect Ophthalmoscope
8
Boring Machine
9
Contact Lens Analyzer
9
Keratometer
10
Perimeter
11
Phoropter
11
Pupillary Diameter Ruler
12
Radiuscope
13
Retinoscope
14
Snellen’s Chart
15
Slit Lamp Biomicroscope
15
Synoptophore
16
4
Tonometer
17
Trial Case
18
Visual Analyzer
19
REFERENCES
20
5
INSTRUMENTS USED IN THE PRACTICE OF OPTOMETRY
In line with the duties of an optometrists, this presents the various equipment used
in the practice as well as its definition, features and functions. The assigned equipment
are as follows in chronological order:
AUTOMATIC EDGER
Definition
Machine used for optical lens edging. Cutting optical lenses to be fitted into
frames. Initially, lens edgers with a set pattern for manual lens edging were
employed for the process of edging. However, technological advances in the
market have led to the development of automatic pattern less lens edgers.
Image 1. Automatic Edger
Functions
It edges, cuts or grinds optical lenses for proper fit into the selected frame.
AUTOMATIC REFRACTOMETER
Definition
Automatic refractometers automatically measures the refractive index of a
sample. The automatic measurement of the refractive index of the sample is based
on the determination of the critical angle of total reflection. A light source, usually
a long-life LED is focused onto a prism surface via a lens system.
6
Image 2. Automatic Refractometer
Functions
Automatic refractometer is used to determine the concentration of a material
by taking automated measurements of a liquid, gel or solid material’s refractive
index. Refractometers operate by passing a beam of light through the sample and
a prism.
BALANCE BOARD
Definition
The balance board addresses the concept that while the eyes are part of
the body, they must move independently of the head and the body. Eye
movements are deemed inefficient if there is accompanying body and/or head
movement.
The balance board is a square wooden board with a base. The base can be
square or round and there are several levels of difficulty.
The patient stands on the board and attempts to shift his hips only from side
to side. It is harder than it seems, and some patients have to start at a lower level
and stand on the board or perform the activity holding the therapist’s hands.
7
Image 3. Balance Board
Functions
Vision Therapy establishes and supports visual function that will remain
stable and comfortable under a variety of conditions. Ideally, this function should
be linked to comfortably stable posture, balance, and whole body function.
The goals include embedding ideal cortical motor programs as well as
stabilizing local dysfunction.
BINOCULAR INDIRECT OPHTHALMOSCOPE
Definition
It is a subcategory of the Indirect Ophthalmoscope in which examines the
eye in more than one view to provide a better view of the inner eye. They are head
mounted.
Image 4. Ophthalmoscope
8
Functions
It projects three elements into the eye, rather than one, allowing the
optician, optometrist or ophthalmologist to get a 3 dimensional view of the interior
of the eye which allows for a more thorough examination.
BORING MACHINE
Definition
It is used to mill, drill, bore, and cut using a rotating tool. It is also used to
drill closed or open openings in solid materials.
Image 5. Boring Machine
Functions
Boring Machines are used to cut and shape lenses.
CONTACT LENS ANALYZER
Definition
A soft contact lens measuring device. A cylindrical lens support defines a
cavity and pedestal for immersing a soft contact lens in a saline solution. A piston
engages the support and can be operated by the user to force air in controlled
amounts through a narrow passageway extending up through the pedestal to the
saline solution.
9
Image 6. Contact Lens Analyzer
Functions
It forms bubbles and rises until it is trapped by the lens. The interface
between the bubble and the lens makes a convenient surface for focusing a
radiuscope to allow lens dimensions to be determined.
KERATOMETER
Definition
A keratometer, also known as an ophthalmometer, is a diagnostic
instrument for measuring the curvature of the anterior surface of the cornea,
particularly for assessing the extent and axis of astigmatism.
Image 7. Keratometer
10
Functions
It is used for measuring the radius of curvature of the anterior (front) surface
of the cornea.
PERIMETER
Definition
An instrument for measuring the angular extent and the characteristics (e.
g. presence of scotoma) of the visual field.
Image 8. Perimeter
Functions
It helps determine any deficiencies in patients’ field of vision. Perimeter
tests a patient’s entire scope of vision, essentially detecting any issues in both
central and peripheral vision. Perimeter testing can also help monitor vision after
diagnosis to ensure glaucoma treatment is effective in preventing further vision
loss. The more vision loss means optic nerve damage.
PHOROPTER
Definition
Phoropter is an instrument used to test individual lenses on each eye during
an exam. Phoropter is a common name for an ophthalmic testing device, also
called a refractor.
11
Image 9. Phoropter
Functions
It is used to manually determine “refraction” – exactly how a lens must be
shaped and curved to correct your vision to a normal state, nothing more.
It is an ingenious way to quickly determine the exact vision correction
needed by your individual eyes. It is used to measure an individual's refractive
error and determine his or her eyeglass prescription.
PUPILLARY DISTANCE RULER
Definition
Pupillary Distance (PD) Ruler – is a measuring device that determines the
space between the pupils of the eyes measured in millimeters (mm).
Image 10. Pupillary Diameter Ruler
12
Functions
It is used when preparing to make prescription eyeglasses. It is used to
determine where you look through the lens of your glasses. It is used to make sure
that the optical center of the lenses matches the eyes of the patient.
RADIUSCOPE
Definition
The radiuscope is designed to accurately measure the radius of curvature
of the anterior and posterior surfaces of rigid contact lenses. It uses the fact that
there are two positions in which the object and image coincide for a curved mirror;
at the center of curvature of the mirror and at the surface of the mirror.
The radius of curvature of the surface is the physical distance of the
instrument moves between the two positions of image focus. It can also function
to assess the surface quality of a right lens to help ensure accuracy when using
this equipment.
Image 11. Radiuscope
Functions
A radiuscope produces virtual object conjugated to the eye of the observer.
The observer adjusts the instrument up and down until he finds two different
positions at which he/she can see the image of that object clearly.
13
It measures the radius of curvature of the surfaces of a contact lens. It is
based on the Drysdale method.
RETINOSCOPE
Definition
A hand held instrument called a retinoscope projects a beam of light into
the eye. When the light is moved vertically and horizontally across the eye, the
examiner observes the movement of the reflected light from the back of the eye.
This reflection is called red reflex.
The examiner then introduces lenses in front of the eye and as the power
of the lenses changes, there is a corresponding change in the direction and pattern
of the reflection. The examiner keeps changing the lenses until reaching a lens
power that indicates the refractive error of the patient.
Image 12. Retinoscope
Functions
The instruments are used to illuminate the internal eye and to observe and
measure the rays of light as they are reflected by the retina. In this way, the
optometrist can achieve an objective examination of the eye and the manner in
which it functions as an organic optical instrument.
14
SNELLEN’S CHART
Definition
The visual acuity test is used to determine the smallest letters you can read
on a standardized chart (Snellen chart) or a card held 20 feet (6 meters) away.
Special charts are used when testing at distances shorter than 20 feet (6 meters).
Some Snellen charts are actually video monitors showing letters or images. It was
developed by the Dutch ophthalmologist Herman Snellen in 1862.
It consists of 11 lines of block letters, also known as “optotypes,” which are
constructed according to strict geometric rules and whose size decreases on each
lower line of the chart.
Image 13. Snellen’s chart
Functions
Snellen’s eye chart is used to measure visual acuity by determining the level
of visual detail that a person can discriminate.
SLIT LAMP BIOMICROSCOPE
Definition
The biomicroscope consists of an illumination system, an observation
system, and the necessary mechanical apparatus for their support and
coordination. The illumination system is in the form of a bright, focal source of light
with a slit mechanism and circular apertures of various sizes.
15
The observation system is a binocular microscope capable of a wide range
of magnification. When using the biomicroscope, the examiner typically illuminates
an ocular structure with the beam of the desired width and observes the structure
at an oblique angle.
In terms of design, there are two major types of biomicroscopes:
1. Zeiss biomicroscope - light source is located below the level of the slit,
near the base of the instrument.
2. Haag-Streit biomicroscope - light source is located at the top of the
instrument.
Image 14. Zeiss biomicroscope
Image 15. Haag-Streit biomicroscope
Functions
It enables the practitioner to observe, under magnification, the living tissues
of the eye or images of the fundus.
SYNOPTOPHORE
Definition
It is an instrument which compensates for the angle of squint and allows the
stimuli to be presented to both eyes simultaneously. An ophthalmic instrument
which is used for diagnosing the imbalance of the eye muscle and treating them
by orthoptic methods.
16
Image 16. Synoptophore
Functions
It is used to investigate the potential for binocular functions in the presence
of a manifest squint. It is specifically used in children (from 3 years of age). It is
also used to detect suppression and abnormal retinal correspondence.
TONOMETER
Definition
Tonometers measure the internal pressure of the eye and tonometry is one
of the principal tests for glaucoma, but until relatively recently their use in the eye
examination was far from routine. A patient's intraocular pressure (IOP) should
normally be 15. Any reading in the region of 21 or 22 signifies an increased
likelihood that the patient will go on to develop glaucoma.
Image 17. Tonometer
17
Functions
It is used for continuous measurements of IOP. It used in experiment,
research work on animal eyes. It uses same prisms as goldmann.
TRIAL CASE
Definition
The trial lens set and trial frame constitute the simplest form of
instrumentation for use in clinical refraction. The typical trial lens set incorporates
pairs of plus and minus spherical lenses ranging from ±0.12 to ±20.00D, pairs of
minus cylinders ranging from -0.12 to -6.00D, and pairs of prisms ranging from 1
to 15 Δ or more. It also includes items such as occluders, pinholes, and Maddox
rods.
The trial frame contains cells for four lenses in front of each eye. The
strongest lens is placed in the back cell, with increasingly weaker lenses, as
required, placed in the forward cells. All three of the front cells (one of which will
usually contain a cylindrical lens) can be rotated by turning the knurled knob
located temporal to the lens cell, and a cylinder axis scale is provided for each eye.
Image 18. Trial Frame
Image 19. Trial Case
Functions
These are instruments which are used in the clinical refraction.
18
VISUAL ANALYZER
Definition
The Analyzer can be utilized for screening, observing and aiding the
conclusion of specific conditions. The after effects of the Visual Analyzer recognize
the kind of vision imperfection. In this manner, it gives data with respect to the area
of any sickness forms or lesion(s) all through the visual pathway. This aids and
adds to the determination of the condition influencing the patient's vision. These
outcomes are put away and utilized for checking the movement of vision loss and
the patient's condition
Image 20. Humphrey visual field analyzer
Functions
It is utilized to check the patients' visual field, especially to distinguish
monocular visual field. The Analyzer extends a progression of white light stimuli of
varying intensities (brightness), all through a consistently enlightened bowl. The
patient uses a handheld catch that they press to demonstrate when they see a
light. This assesses the retina's capacity to recognize a stimulus at particular
focuses inside the visual field. This is called retinal affectability and is recorded in
'decibels' (dB).
19
REFERENCES
Last, the College of Optometrist. 2018. Instrument: Perimeter. Retrieved from
https://www.college-optometrists.org/the-college/museum/online-exhibitions/virtualophthalmic-instrument-gallery/perimeters.html
Last, Free Dictionary by Farlex. 2003-2018. what is perimeter?. Retrieved from
https://medical-dictionary.thefreedictionary.com/perimeter
Last, Veatch Opthalmic Instruments. 2018. about Perimeters. Retrieved from
http://www.veatchinstruments.com/about-perimeters
Last, Downing, Elizabeth A. (524 E. Townview Cir., Mansfield, OH, 44907)
Downing, Ronald W. (524 E. Townview Cir., Mansfield, OH, 44907). Soft Contact Lenz
Analyzer. Retrieved from http://www.freepatentsonline.com/4684246.html
Binocular
Indirect
vs.
Direct
Ophthalmoscopes.
(n.d.).
Retrieved
from
https://www.vetachinstruments.com/Binocular-Idirect-vs-Direct-Ophthalmoscopes
Indirect
Ophthalmoscopes.
(n.d.).
Retrieved
from
https://medical-
dictionary.thefreedictionary.com/inderict+ophthalmoscope
ICEE.
2009.
Retinoscopy.
Retrieved
from
http://www.vargellini.it/zaccagnini/download/approfondimenti/optometria/retinoscopia%2
0english.pdf
What is a: Phoropter. (n.d.). Retrieved from http://www.eyeglassguide.com/myvisit/vision-testing/phoropter.aspx
Phoropter. (2018, June 13). Retrieved from https://en.wikipedia.org/wiki/Phoropter
VISUAL
ANALYZER.
(2017,
February
02).
Retrieved
from
http://bigmed.info/index.php/VISUAL_ANALYZER
Boring
machines.
(n.d.).
Retrieved
from
http://www.strojimport.com/products/boring-machines/
Humphrey
visual
field
analyser.
(2018,
August
https://en.wikipedia.org/wiki/Humphrey_visual_field_analyser
20
11).
Retrieved
from