1.
Presented by :-
Optom-Santosh mangate
MGM school of biomedical sciences

2.
Introduction
• The refractometry is an objective method to finding out the error of the
refraction.
• AR is also called as refractometer , optometr and objective refractometer.

3.
History
• Over the last 200 years or so many attempts have been made to automate
process to refraction but with little success.
• Until recently, when successful autorefractors were developed Over the 30
years which could objectively determine a patient refractive status with
an acceptable level of reability.

4.
The scheiner Principle
• Scheiner discovered in 1619 that the point at which an eye was focused
could be precisely determined by placing double pinhole apertures before
the pupil.
• Parallel Rays of light from a distant object Are reduced to too small
bundles of light by the scheirner disc.
• These form a single focus on the retina if the eye is emetropic; but if there
is any refractive error two spots fall on a retina.

5.
Autorefractometer view

6.
Fogging
• Alle autorefractometers now use the fogging technique to relax
accommodation prior to objective refraction.
• These is the reason why patients state the target is blurred prior to
measurements being taken-these is the effect of the fogging lens.

7.
Autorefractometers currently in use
• Autorefractometers are most commonly used to provide the starting point
of refraction to obtain an objective result before performing subjective
refraction.
• Most commercially available Autorefractometers today come with an
inbuilt automated keratometer Are known as auto kerato-refractometer.
• Recently new equipments with additional corneal topographers have
been developed in which corneal topography can also be performed

8.
Features
• The computerised
autorefractometer quickly gives
information about the refractive
error of the patient in form of
sphere, cylinder with axis and
interpupilary distance.
• These method is good alternative
to retinoscope in busy practice.

9.
Indications
• Myopia .
• Hipermetropia.
• Astigmatism .
• Presbyopia.
• Glass priscription.
• Contact lens priscription.
• The starting point for optometrist and ophthalmologist .

10.
• Paediatric refraction
• People with disability requiring glasses

11.
Contraindications
• Mentaly disabled patients
• Patients with postural problems
• Acute troumatic injury to the eye
• Artificial prosthesis
• Very small children
• Patients with accommodation anomalies

12.
Complications
• Poor fixation
- the patient blinks excessively and doesn’t fix the primary point
• High refractive error
- The autorefractors may not be fairly accurate at high refractive errors.
• Media opacity
-such as pterigium, corneal opacity, cataract
• Cost
-they are realatively costly equipment comparatively to retinoscopy Instruements.

13.
Types
• Autorefractometer
Semi automated
Fully automated
• Autokeratorefractometer
• Portable refractometer

14.
Portable autorefractometer

15.
Use of AR
• Estimation of refractive error hipermetropia, myopia ,
astigmatism.
• Vertex distance
• Interpupilary distance
• Mode can be change as phakic eye, pseudophakic eye and
aphakic eye.

16.
Limitations of AR
• Not use for near refraction
• Peripheral light rays from the room can affect the readings so dark
room is required.

17.
Problems can face with
autorefractometer
1. Alignment problem:-
• Improper chin on chin rest
• Improper head on head rest
• Patients not co-operative
- Irregula astigmatism:-
• Axis change
• Irregular mires due to irregular cornea:- pterizium , keratoconus, corneal opacity
Corneal distrophy.

18.
Question for you ?

19.
Thanks for attention 😊