Optometrists are eye care professionals who specialize in detecting and diagnosing visual problems.
They offer routine eye checkups, as well as more in-depth eye tests when there is reason to suspect a patient might have a visual issue.
An eye test is one of the simplest and most affordable ways to catch early signs of vision impairment, especially if you’re at risk of developing cataracts, glaucoma, or other common sight problems.
The entire process of eye test typically takes 20 to 30 minutes – much shorter than you probably expected!
Below we’ll explore what an eye test involves and the importance of booking an appointment in order to receive one.
Many eye tests are designed to evaluate vision and help determine whether a patient’s visual acuity is normal.
There are two types of visual acuity.
Snellen acuity is the ratio of letters a person can read at a distance of 20 feet with normal eyesight. Oxford acuity is the ratio of letters a person can read at a distance of 16 inches with normal eyesight.
Refraction refers to the process of bending light as it enters the eye. The curvature of the cornea and the shape of the lens inside the eye cause light to bend as it travels to the retina, where it is converted into images.
Refraction is the reason why we see clearly when looking at distant objects while close objects appear blurry. The refractive error that occurs in the eye is commonly corrected with glasses or contact lenses.
A refraction test determines the strength and type of corrective lenses that a patient needs. It is often part of an eye exam, and is frequently conducted at the beginning of the appointment.
A patient sits in front of a machine called a phoropter, which projects light into their eyes. Various corrective lenses (including eyeglasses and contact lenses) are placed on the phoropter, and the doctor asks the patient which lens they see the light through the clearest.
Finally, the doctor will use a slit lamp to examine the surface of the eye and look for any abnormalities.
The pupils are the black circles located at the centre of the iris. They control how much light enters the eye and work in tandem with the iris to regulate how much light enters the eye.
The doctor will use a light or a pen that has a light source at the end to check the dilation of the pupils.
Pupil dilation is a common test used to rule out any underlying conditions that could cause visual impairment. It is especially important to check the dilation of the pupils if there is a family history of glaucoma.
There are six muscles that control the movement of the eye. These are extremely important as they maintain healthy eye movement and are responsible for keeping the eyes focused on a single object.
This test is done by having the patient follow the doctor’s finger as it moves around the room. If the patient has a problem with their eye muscles, they will struggle to follow the finger with their eyes.
When done as a part of a full eye exam, the doctor is looking for signs of strabismus, also known as misalignment of the eyes. This can occur when the muscles that move the eyes are weak or misaligned.
The doctor may ask the patient to read aloud while they look into a handheld mirror. This helps the doctor check for signs of misalignment in the eyes.
The external exam is the visual inspection of the eye to rule out any abnormalities. The doctor will be looking for any signs of injury, infection, inflammation, or other abnormalities of the eye. They will also check for redness, tearing, eyelid droop, and any other signs of irritation or discomfort.
The doctor will also be checking for any normal variations in the appearance of the eye. This will include looking for moles, freckles, and other marks on the sclera.
They may also check the eyelashes to make sure they are not too long and causing irritation to the eye or eyelid.
The internal exam is a more detailed examination of the eye. The doctor uses a tool called a speculum to open the eyelids and hold them open. This will give the doctor a better look at the inside of the eye and allow them to check for any abnormalities.
The doctor will be looking for signs of infection, damage to the retina, and other abnormalities.
They will also be checking the colouration of the eye, the veins, and the blood flow in the back of the eye. In some cases, the doctor may be able to detect early signs of degenerative eye diseases like macular degeneration or glaucoma by examining the inside of the eye.
The majority of people are able to see the full spectrum of colours.
However, a small number of individuals are colour blind, meaning they can only see a partial colour spectrum. This can be a genetic condition, or it can occur after a person has suffered from a condition that affects the eyes.
Most doctors will run a colour blindness test as part of an eye exam, especially if there is a family history of colour blindness or if the patient has had a condition that affects the eyes.
A colour blindness test is conducted by placing a colour swatch in front of the eyes of the patient. The doctor will ask the patient what colour they see, and they will record the response. After doing this with several different colour swatches, the doctor will be able to determine if the patient is colour blind.
How often should you get your eyes tested?
A basic eye exam includes an examination of your eye’s internal structures, a visual acuity test, and an assessment of your eye health. It’s important to note that the wait time for an eye test may vary depending on the time of year and day of the week.
Do not delay your eye test. Book an appointment every five years if you are between the ages 20 to 39, two to four years if you are 40 to 54 years old, and one to three years if you are 55 to 64 years old.
However, If you have reason to believe you may have an eye condition, you may want to schedule an appointment in order to get in to see an eye doctor as soon as possible.