Patient Information

Eye Tests

The Research Unit at the Research Foundation, Royal Victoria Eye & Ear Hospital has state-of-the-art equipment designed to analyse various aspects of visual function. Your eye doctor may request that one or more of these tests be performed so as to help come to a precise diagnosis of your particular condition.

Eye Tests

These tests may be divided into 2 groups:

Broadly speaking, psycho-physical tests involve presenting a visual signal which the patient must interpret. Electro-physical tests involve the technician measuring a small electrical signal generated in some portion of the patient's visual pathway in response to a visual stimulus. These tests do not require that the patient interpret or actively respond to the stimulus.

If you wear distance or reading glasses please ensure to bring these to the appointment.

Psychophysical testing

Snellen Visual Acuity

This test, first developed by the Dutch ophthalmologist, Herman Snellen in 1862, involves the patient reading a series of letters of decreasing size, from a standard distance. Although every aspect of this test is carefully controlled it is an easy test for patients to perform.
Please remember to bring any glasses you use for either driving or reading with you for this test. If you have difficulties with letters please do not hesitate to mention this to the examiner as the test can be adapted to suit your needs.

Perimetry Tests (Humphrey & Goldmann Visual Field Tests)

This test is also known as visual field testing, may be requested if there is any suspicion that you have an eye disorder which might result in loss of peripheral (side) vision or of central vision. Such conditions include Glaucoma, Age Related Macular Degeneration or a variety of inherited degenerations of the retina, the light-sensing layer of the eye.

Goldmann Perimetry

This test takes approximately 30 minutes to perform. Please bring your glasses with you for this test.
You will look into the interior of a large bowl. One eye will be tested at a time. It is very important that you concentrate on looking at a small black spot at the very centre of the bowl throughout the test. White, spot targets, varying in size and brightness, will be brought in from the edge of the bowl towards the centre. As soon as you first see the spot target you must press a buzzer to alert the examiner to the fact that you have detected the target. The circumference of your visual field to each target will be carefully mapped. Usually 3 different targets, of reducing size, are used. Any defects within your visual field will be carefully mapped out.

Humphrey Automated Permetry

This test also measures the visual field. It takes approximately 30 minutes to perform. One eye is tested at a time. You will look into the interior of a large bowl. Spots of light, varying in size and brightness, will appear randomly on the surface of the bowl. As soon as you see a spot you should press the buzzer. The presentation of the spots, as well as their size and brightness, is controlled by a computer.

Colour Vision Tests incl. Farnsworth Munsell 100 Hue Test; Lanthony D15

These are tests of colour vision. One or other of these tests may be requested for certain occupations, e.g. electricians, fire service, if there is a family history of colour blindness or if there is a suspicion that a retinal or optic nerve disease may have affected colour vision.
The Farnsworth Munsell Test may take up to 30 minutes. The Lantony D15 test may take 15 minutes. Please bring your reading glasses with you for either of these tests.
You will sit at a specially lit cabinet. This test may be performed using both eyes or you might be tested one eye at a time. You will be asked to arrange small coloured caps in order of shade. You may take your time in arranging the caps and change your mind until you are happy with your selection. The technician will record the order in which you arrange the caps and analyse to see if the number of errors falls within the normal range for your age. Certain patterns of arrangement of the caps are characteristic of particular types of colour blindness.

A Scan, Biometry (15 mins)

Measures the size of the lens within your eye normally required if you are having cataract surgery.

Electrophysical testing

Pattern Electroretinogram (PERG) (20 mins)

This measures the function of the central retina, the macula, which you use for detailed vision e.g. reading.
You will be asked to look at a moving checkerboard pattern on a TV whilst we record the small electrical signals generated in the macula.

Visual-evoked potential (VEP) (30 mins)

Investigates the pathways carrying signals from the eye to the brain via the optic nerves, and how the brain interprets these signals.
You will be asked to watch a moving checkerboard pattern on a TV or flashes of light while we record the electrical signals.

Electroretinogram (ERG) (1hr)

This measures the electrical response of the light-sensitive cells in the eye, the rods and cones. It also measures the retinal function. Prior to this test, you will be given drops in your eyes to dilate the pupils. You will also be given anaesthetic drops to numb your eyes. A special type of recording contact lens will then be placed over your eye and electrodes will be placed on the skin near the eye. You will be asked to watch some flashing lights, these are used to stimulate the retina. The electrodes measure the electrical response of the retina to the flashing lights. The test will be performed first in a dark room and then again when the lights are turned on. The test does not cause any pain, but some people may find it uncomfortable. Because of the drops used, you will be advised not to drive to the appointment, as you may notice that your vision is blurred for some time after the appointment.
The test will take 1 hour.

Dark Adaptometry (30 mins)

When we come from bright light into semi-darkness it takes some time for us to be able to make out shapes and shadows. This test examines how well you can see in low light and how long it takes for your eye to adapt.The test takes approximately 35 minutes.
Your pupil will be dilated. Do not drive in for this test as the pupil dilation will make it unsafe for you to drive for some hours after the test.
You will look into the interior of a brightly lit bowl for 5 minutes. The light in the bowl will be turned out and every minute you will be asked to say when you detect a large white spot of light. The intensity at which you detect this spot will be recorded over the following 30 minutes.

Multifocal ERG (50 mins)

Measures the function of the boundary between the retina and the layer under the retina (Retinal Pigment epithelium). You will be asked to make small eye movements between 2 red lights for 40 secs every minute for 15 mins in the dark and 15 mins in the light.

Fundus Photographs

This test takes a photograph of the retina fundus at the back of the eye using a special camera. The images will show any changes or abnormalities in the back of the eye. You will be advised not to drive to the appointment as you will be given drops to dilate your eyes before the test.

Counselling Service

Mary Lavelle

A counselling and support service is provided to the Research Department in the Royal Victoria Eye and Ear Hospital every Wednesday morning from 10.00am. to 1.00pm. for newly-diagnosed patients and their families and also for patients on follow-up visits.

This service is provided by Insight Counselling Centre, an initiative of Fighting Blindness. The Centre was established in 2002 with the objective of providing practical help, emotional support and psychotherapy to individuals experiencing sight loss, as well as to their families. Sight loss impacts in very many different ways and at many different levels on individuals and their families. The onset of sight loss can change one’s relationship with self and others and reaching out for support in these circumstances can be very beneficial. The Centre provides a safe place for exploring matters of concern and help in finding a way through what can be a difficult and frightening time

On-going counselling is also available Monday to Friday at the Insight Counselling Centre premises at 4 South Great George’s Street. The service is provided free of charge by Fighting Blindness and is open to referrals from the clinical staff.

What do I have to do?

  • Please be on time for your tests in order to prevent your tests being delayed and out of courtesy to other patients and staff.
  • It is VERY important that you bring all current glasses and recent prescriptions to your appointment.
    If you wear contact lenses, please bring your lens case and any necessary solutions, as we may need you to remove them.
  • Your hair should be freshly washed and free from all oils, gels, sprays, etc. Please do not wear eye makeup
  • If there are children accompanying you to the appointment please ensure there is someone responsible for them as there are no childcare facilities in the department.

Are there any side effects?

Dilating drops will cause temporary blurring of vision and increased sensitivity to sunlight, but this will wear off after a few hours.
You may wish to bring dark glasses to wear afterwards.

You should NOT drive after having dilating drops.

What happens afterwards?

A report will be sent to the consultant who referred you.
The results of the tests will not be given to you at the time of testing.

How to get there

Parking

On-street parking is available which is pay and display. A limited number of disabled parking spaces are available on the hospital grounds please contact us for details on 01-6343630.

Public Transport
Taxi

If you need a taxi we would be happy to order one for you, please ask at reception.

In accordance with the current legislation, smoking is prohibited in all areas of the Royal Victoria Eye & Ear Hospital.