Optics: Emmetrop + Ametrop Flashcards
What is a good solution to obtain answers to problems and clinical cases?
Schematic eye
Radius of curvature of the reduced eye:
5.55mm
How many refracting surfaces does a reduced eye have?
1
What isIndex of refraction of a reduced eye?
1.333
What is the axial length of the reduced eye?
22.00
Primary adn secondary focal lengths of reduced eye:
-16.67 and +22.22 mm
The reduced eye dioptric power?
+60D
What is the image vergence for an object at infinity?
Zero
When an infinitely distant object is focused on the retina of the reduced eye, the eye is said to be ______________
Emmetropic
What is another way to say that the eye is emmetropic?
The retina is conjugate with infinity
What is the far point of the eye?
Farthest distance at which an object can be seen clearly without any accommodation
What is the far point of a emmetrope?
Optical infinity
Ametropia is when…
An infinitely distant object is not focused on the retina
What are the two common forms of ametropia?
Myopia and hyperopia
Axial hyperopia:
-eye is too short
-axial length less than 22.22 mm
Refractive hyperopia:
-eye is too weak relative to reduced eye
-refractive power is less than +60D
Axial myopia:
-eye too long relative to reduced eye
-axial length is greater than 22.22mm
Refractive myopia:
-eye is too strong relative to reduced eye
-refractive power is greater than +60D
Are myopes near-sighted or far sighted?
Nearsighted
Where does the image form in regards to the Reina in a myope?
In front of the retina
Where/what is the far point in a myopic eye?
It is a real point located at a finite distance in front of the eye
