Zusammenfassung der Ressource
Ophthalmology:
Optic Testing
- Number
- Rational Number
- Precise measurements in
units such as millimetres
- In the fraction 20/20 - the numerator is
the distance in feet between the subject
and the eye chart. The denominator is
the distance frm which a normal person
can read the 8th line - 1 arc minute
- Whole Number
- Eye measurements are
usually in millimetres (mm)
- Geometry
- Circles &
Domes
- Pupil
- Iris
- Sphere
- Shape of an eyeball
- Measurement
- Angles
- Angles of light
reflection in the
eye
- 1 minute of arc (1 minute
is 1/60 of a degree)
- Diameter
- Measuring the cross distance
of certain circular shapes in
the eye such as the iris
- Radius
- Circumference
- Determining
dilation/constriction of
the pupil
- They use trigonometry to
determine the height of letters
in an eye testing chart
- Placing an eye chart on a wall involves specific
mathematic measurements such as angle of
where a letter is in relation to a person's eye
and distance of chart from the viewer
- The minimum average
separation of two lines (depicted
in a letter) that a person can see
is an angle of 1 minute arc