Refractive Error

Myopia (short-sighted)

“ My book is in focus, but I can’t see the TV clearly”

• This occurs when light focuses in front of the retina instead of directly on it.
• This can be caused either by a steeper cornea or a longer than normal eye.
• Signs and Symptoms
  • Blurred distance vision
  • Clear near vision
  • Vision seems to get clearer when squinting
  • Poor distance vision at night

Hyperopia (far-sighted)

“ I can see my TV clearly, but struggle to read my book”

• This occurs when light focuses behind the retina instead of directly on it.
• This can be caused either by a flatter cornea or a shorter than normal eye.
• People suffering from this have trouble with near vision but may have difficulty with distance vision as well.
• Signs and Symptoms
  • Difficulty with near vision
  • Blurred distance vision
  • Eye fatigue when reading
  • Eye strain, headaches and burning eyes
  • Crossed eyes in children

Astigmatism

“You have rugby ball eyes”

• This means that the corneal or lens surface is oval like a rugby ball instead of spherical like a soccer ball.
• This causes light to focus on more than one point in the eye, which results in blurred at distance and/or near.
• Signs and Symptoms
  • Poorer vision in dull lighting
  • Blurred vision near and/or at a distance
  • Eye strain and headaches

Presbyopia

“My arms are getting too short”

• This is a term that is used to describe an eye which lost its natural focusing power (accommodation).
• At about 40 years of age, the lens becomes less flexible and focusing power is gradually lost.
• This is a natural and unavoidable ageing process.
• Signs and symptoms
  • Brighter and more direct light is needed for reading
  • Difficulty seeing small print at a short distance
  • Reading material must be held at further distance
  • Slow focusing from distance to near

Pathology

Cataract

• This occurs when the lens within the eye has progressive clouding.  This results in impaired or cloudy vision.
• Signs and symptoms
  • Blurry or misty vision
  • Distorted colours
  • Increased sensitivity to light

Glaucoma

• This condition causes damage to the optic nerve (this transmits images to the brain).  It is often associated with a build-up of pressure in the eye.  It can be inherited.  Without treatment glaucoma can cause total permanent blindness.
• Signs and symptoms
  • No symptoms, no pain, no redness
  • Slow loss of peripheral vision.