Topic 2 - Structure And Function Of The Eye And Defects Of The Eye And Their Treatment Flashcards
What is the main function of the eye?
The eye is a sense organ containing receptors sensitive to light intensity and colour.
What is accommodation in the context of the eye?
Accommodation is the process that allows the eye to change its shape to focus on near or distant objects.
What is the retina?
The retina is a layer of light sensitive cells found at the back of the eye.
What happens when light hits the retina?
The cells are stimulated and impulses are sent to the brain, which interprets the information to create an image.
What are rod cells and cone cells?
Rod cells are more sensitive to light and better for seeing in low light; cone cells allow for colour vision.
What is the function of the cornea?
The cornea is the see-through layer at the front of the eye that allows light through and focuses light onto the retina.
What is the role of the iris?
The iris contains muscles that contract or relax to alter the size of the pupil.
How does the pupil react in bright light?
In bright light, the circular muscles contract and radial muscles relax, making the pupil smaller.
How does the pupil react in dim light?
In dim light, the circular muscles relax and radial muscles contract, making the pupil larger.
What is the function of the ciliary muscles and suspensory ligaments?
They hold the lens in place and control its shape to allow focusing on objects at different distances.
What is the lens?
The lens is a transparent, curved surface on the front of the eye that reflects light onto the retina.
Describe the process of accommodation for a near object.
The ciliary muscles contract, the suspensory ligaments loosen, and the lens becomes thicker and more curved.
Describe the process of accommodation for a distant object.
The ciliary muscles relax, the suspensory ligaments tighten, and the lens becomes thinner.
What is myopia?
Myopia, or short sightedness, occurs when the lens is too curved, causing distant objects to appear blurry.
What is hyperopia?
Hyperopia, or long sightedness, occurs when the lens is too flat, preventing adequate refraction of light.
What does cataracts mean?
Clouding of the lens of the eye
Cataracts can occur congenitally or develop over time, restricting vision and often treated through surgery.
What is colour blindness?
Inability to see certain colours
Full colour blindness is rare, while specific colour blindness (e.g. red-green) is common and usually genetic.
What causes specific colour blindness?
Not having enough cone cells in the retina
Cone cells are responsible for colour vision.
What are the treatment methods for eye defects?
Spectacle lenses, contact lenses, laser eye surgery, replacement lens
Each method addresses different vision issues, such as myopia and hyperopia.
What type of lenses are used to treat myopia?
Concave lenses
Concave lenses spread out light to improve vision for myopic patients.
What type of lenses are used to treat hyperopia?
Convex lenses
Convex lenses bring light rays together to improve vision for hyperopic patients.
What is the function of contact lenses?
Work like glasses but allow for sports and activities
Contact lenses can be hard or soft and have different lifespans.
What does laser eye surgery do for myopia?
Reduces the thickness of the cornea
This adjustment results in less refraction of light.
What does laser eye surgery do for hyperopia?
Changes the curvature of the cornea
This adjustment increases the refraction of light.
What is a common treatment for hyperopia?
Replacement lens
An artificial lens made of clear plastic can replace the natural lens.
What are the risks associated with lens replacement surgery?
Damage to retina or cataracts developing
These complications can arise from surgical procedures on the eye.
