12 common eye conditions: What they look like and how to spot them
What is World Sight Day?
World Sight Day is an annual event that raises awareness of vision impairment and the importance of looking after your eyes. Coordinated by the International Agency for the Prevention of Blindness (IAPB) since 2000, this year’s theme is #LoveYourEyes.
The aim? Encourage millions of people to book a comprehensive eye exam and take simple steps to protect their sight before small issues become bigger problems.
Eye health in Britain: why it matters
Eye health plays a bigger role in everyday wellbeing than many of us realise.
According to the Royal National Institute of Blind People (RNIB), over 2 million people in Britain are expected to experience mild to moderate sight loss by 2025, rising to 2.3 million by 2030. That means millions of people may rely on glasses or contact lenses to support their vision.
RNIB projections suggest that by 2025:
- Macular degeneration: Over 4.6 million people
- Diabetic retinopathy: 1.49 million people
- Ocular hypertension: 1.42 million people over 30
- Cataracts: 786,000 people
- Glaucoma: 760,000 people
Some of these conditions are widely recognised. Others are less familiar, which is why knowing what to look for can make all the difference.
Below, we’ve outlined 12 common eye conditions and what changes in vision may look like.
12 common eye conditions
1. Astigmatism
Astigmatism is a type of refractive error that causes blurred or distorted vision. It happens when the eye is shaped more like a rugby ball than a football, meaning light focuses at multiple points instead of one.
It’s usually corrected with glasses or toric contact lenses.
Normal Vision
Astigmatism
2. Short-sightedness (Myopia)
Myopia is another refractive error where distant objects appear blurry.
You may notice:
- Difficulty reading signs at a distance
- Sitting closer to screens
- Frequent headaches
- Eye rubbing
Normal Vision
Myopia
3. Long-sightedness (Hyperopia)
Hyperopia affects your ability to focus on nearby objects. In moderate to high cases, distance vision may also be affected.
Common signs include:
- Squinting
- Tired eyes after reading
- Eye strain during screen use
Normal Vision
Hyperopia
4. Colour vision deficiency
Often inherited, colour vision deficiency affects how the eye’s cones detect colour.
Types include:
- Protanopia – reduced sensitivity to red light
- Deuteranopia – reduced sensitivity to green light
- Tritanopia – reduced sensitivity to blue light
Complete colour blindness is rare, but red-green deficiency is the most common.
Normal Vision
Protanopia
Tritanopia
Deuteranopia
5. Presbyopia
Presbyopia develops naturally with age as the lens becomes less flexible. It makes focusing on close work — like reading or sewing — more difficult.
It’s a common age-related refractive change rather than a disease.
Normal Vision
Presbyopia
6. Glaucoma
Glaucoma occurs when damage to the optic nerve gradually affects vision, often starting at the edges (peripheral vision).
Early stages may have no noticeable symptoms, which is why routine eye tests are important.
Normal Vision
Early Glaucoma
Advanced Glaucoma
Extreme Glaucoma
7. Macular degeneration (AMD)
Age-related macular degeneration affects central vision by damaging the macula — the part of the retina responsible for sharp, straight-ahead sight.
It can make reading, recognising faces and driving more difficult.
Normal Vision
Macular Degeneration Stage 1
Macular Degeneration Stage 2
Macular Degeneration Stage 3
8. Diabetic retinopathy
A complication of diabetes, this condition damages blood vessels in the retina due to high blood sugar levels.
Left untreated, it can lead to sight loss — but early detection makes management much more effective.
Normal Vision
Diabetic Retinopathy
9. Cataracts
Cataracts cause the normally clear lens of the eye to become cloudy.
You might notice:
- Blurred or misty vision
- Difficulty seeing at night
- Sensitivity to light
- Colours appearing faded
Cataracts usually develop gradually.
Normal Vision
Cataracts
10. Retinitis pigmentosa (RP)
Retinitis pigmentosa is a group of inherited conditions that cause progressive degeneration of the retina.
Early signs include difficulty seeing in low light (night blindness). Over time, peripheral vision narrows, sometimes leading to tunnel vision.
Normal Vision
Retinitis Pigmentosa
11. Double vision (Diplopia)
Double vision occurs when one object appears as two images.
It can result from issues with eye muscles or nerves. Sudden onset double vision should always be assessed by an optometrist.
Normal Vision
Double Vision (diplopia)
12. Floaters
Floaters are small specks or squiggly lines that drift across your field of vision. They are common and usually harmless.
However, a sudden increase in floaters — especially with flashes of light — may indicate a retinal issue and should be checked promptly.
Normal Vision
Floaters
How can you tell if you have an eye condition?
Vision changes are not always dramatic. Sometimes they develop slowly, making them easy to overlook.
You may want to book an eye test if you notice:
- Blurred or distorted vision
- Difficulty focusing near or far
- Frequent headaches
- Increased light sensitivity
- Reduced peripheral vision
- Sudden visual disturbances
Even mild changes in visual acuity can signal an underlying issue. A comprehensive eye exam can identify refractive errors and screen for more serious eye conditions.
When should you see an optometrist about vision changes?
While many vision changes are manageable, some symptoms require prompt attention.
Book an appointment as soon as possible if you experience:
- Sudden loss of vision
- A rapid increase in floaters
- Flashes of light
- A shadow or curtain effect in your vision
- Sudden double vision
Regular eye tests are one of the simplest ways to protect your sight. Even if your vision feels stable, routine checks help detect early signs of glaucoma, diabetic retinopathy and macular degeneration before they affect daily life.
Looking after your eyes doesn’t need to feel complicated — small, consistent steps make a big difference.
Roshni Patel BSc (Hons) MCOptom
Optometrist and Professional Services Manager
