Ametropia Flashcards
What is ametropia?
Ametropia is a group of refractive errors where light does not focus correctly on the retina.
What are the main types of ametropia?
Myopia (short-sightedness), hyperopia (long-sightedness), and astigmatism.
What is myopia?
A refractive error where light focuses in front of the retina, causing difficulty seeing distant objects.
What is hyperopia?
A refractive error where light focuses behind the retina, causing difficulty seeing near objects.
What is astigmatism?
A refractive error caused by an irregularly shaped cornea or lens, leading to distorted or blurred vision.
What is the pathophysiology of myopia?
An elongated eyeball or excessive curvature of the cornea causes light to focus in front of the retina.
What is the pathophysiology of hyperopia?
A shortened eyeball or insufficient curvature of the cornea causes light to focus behind the retina.
What is the pathophysiology of astigmatism?
Uneven curvature of the cornea or lens results in multiple focal points, distorting vision.
What is emmetropia?
Normal vision where light focuses directly on the retina.
What are common symptoms of myopia?
Blurred distance vision, squinting, and difficulty seeing road signs or whiteboards.
What are common symptoms of hyperopia?
Eye strain, headaches, and difficulty focusing on near objects, especially after prolonged reading.
What are common symptoms of astigmatism?
Blurred or distorted vision at all distances, eye strain, and headaches.
What are the risk factors for myopia?
Family history, prolonged near work (e.g., reading, screen use), and insufficient outdoor activity.
What are the risk factors for hyperopia?
Family history, older age, and certain medical conditions like diabetes or small eyeballs.
How is ametropia diagnosed?
Comprehensive eye examination including visual acuity testing and refraction assessment.
What is the Snellen chart?
A tool used to assess visual acuity by asking patients to read letters at a standardised distance.
What is the management for myopia?
Corrective lenses (glasses or contact lenses), orthokeratology, or refractive surgery like LASIK.
What is the management for hyperopia?
Convex lenses in glasses or contact lenses, and in some cases, refractive surgery.
What is the management for astigmatism?
Corrective lenses, including toric lenses, or refractive surgery.
What is orthokeratology?
A non-surgical treatment using specialised contact lenses to temporarily reshape the cornea.
What is LASIK surgery?
A type of refractive surgery that reshapes the cornea to correct refractive errors.
What lifestyle factors can reduce the risk of developing myopia?
Spending more time outdoors and reducing prolonged near work like reading or screen time.
What are complications of untreated ametropia?
Eye strain, amblyopia (“lazy eye”) in children, and reduced quality of life due to poor vision.
What is the role of refraction assessment in ametropia?
It determines the degree of refractive error and helps prescribe corrective lenses.
What is presbyopia, and how is it different from ametropia?
Presbyopia is age-related difficulty focusing on near objects due to lens stiffness, not a refractive error.
