Optics:Formula Sheet Flashcards
Rayleigh’s criterion
the central maximum of one image falls on the first minimum of another image, the image is said to be just resolved
What are the four acuity tasks?
- Minimum detectable
- Minimum separable
- Minimum cognizable
- Minimum discriminable
What is mimunim detectable?
Ability to detect if an object is present on an empty space
What is Minimum separable?
Ability to discriminate two spatially separated objects
What is minimum cognizable?
Ability to recognize or name an object
What is minimum discriminable ?
Surpasses the acuity limit (vienier acuity)
What is visual acuity?
Ability to resolve fine detail in a pattern
What is the point of visual acuity?
Reducing the size of the pattern until the smallest detail can be resolved
Visual acuity is expressed as the
Reciprocal of the size of the smallest detail
Each stoke subtends ________ so 1 letter subtends _______
1 minute of arc, 5 minutes of arc
What are the numerator and denominator of visual acuity?
Numerator- viewing distance
Denominator- size of the letter
What scientist defined sharpness of vision?
Franciscus Cornelius Donders
What clinician defined optotypes and put them in a chart so they subtended 5 minutes?
Herman Snellen Sr. (Queen of optometry)
Which scientists used no- serif letters and reduced visual clutter for the chart?
John Green Sr.
Snellen acuity is equal to the reciprocal of ___.
MAR
What is immune angle of resolution?
-Expresses angular size of detail within the optotype at threshold
-just resolvable angle
What is the radius of curvature of the reduced eye?
5.55mm
What is the refractive index of the reduced eye?
1.333
What is the axial length of the reduced eye?
22.00mm
What is the power of the reduced eye?
60D
What is the primary focal length of the reduced eye?
-16.67 mm
What is the secondary focal length of the reduced eye?
+22.22mm
