Royal Air force rule or RAF rule Part 1
The royal Air force rule is also called RAF near point rule. It is used to measure the near point of convergence and near point of accommodation. This royal Air force rule is called so, because it is first used in United Kingdom to access the visual abilities in US millitry. NEAR POINT OF CONVERGENCE: the point nearest to the eye where a person uses maximum convergence but the retina received a focused image of the object is called near point of convergence. NEAR POINT OF ACCOMMODATION: the point nearest to the eye where a person uses maximum accommodation but the retina received a focused image of the object is called near point of ACCOMMODATION. The royal force rule has different parts, Cheek rest, which is V shaped and it is 6cm long. Square rule. Which has equivalent dioptric sacle. Scale which access the normal, abnormal and reduced convergence. Expected age scale. And last but not the least, Centimeter scale. The total length of RAF ruler is 50cm. RAF rule has a movable drum which can slide on square rod. The target drum has 4 different targets. 1. Dot on vertical line which is used to rule out the near point of convergence 2. Photograph of General post office telephone directory which is used to access near point of accommodation. 3. Reduced snellen chart, this chart is about 1/17 times reduced than distance snellen chart which we used from 6 meter. And the reduced snellen chart substend an able of 5 minute of arc from 35centimeter and distance snellen chart substend angle of 5 minute of arc from 6 meter. And this reduced snellen chart is used to access near point of accommodation 4. Near vision chart, which has 4 lines,having times Roman form, the standard spacing. And this near vision chart is used to access near point of accommodation. A Handle which hold by examiner. This video is just about different parts of the Royal air force ruler in next video we will discuss the proper procedure of the royal air force ruler.
The royal Air force rule is also called RAF near point rule. It is used to measure the near point of convergence and near point of accommodation. This royal Air force rule is called so, because it is first used in United Kingdom to access the visual abilities in US millitry. NEAR POINT OF CONVERGENCE: the point nearest to the eye where a person uses maximum convergence but the retina received a focused image of the object is called near point of convergence. NEAR POINT OF ACCOMMODATION: the point nearest to the eye where a person uses maximum accommodation but the retina received a focused image of the object is called near point of ACCOMMODATION. The royal force rule has different parts, Cheek rest, which is V shaped and it is 6cm long. Square rule. Which has equivalent dioptric sacle. Scale which access the normal, abnormal and reduced convergence. Expected age scale. And last but not the least, Centimeter scale. The total length of RAF ruler is 50cm. RAF rule has a movable drum which can slide on square rod. The target drum has 4 different targets. 1. Dot on vertical line which is used to rule out the near point of convergence 2. Photograph of General post office telephone directory which is used to access near point of accommodation. 3. Reduced snellen chart, this chart is about 1/17 times reduced than distance snellen chart which we used from 6 meter. And the reduced snellen chart substend an able of 5 minute of arc from 35centimeter and distance snellen chart substend angle of 5 minute of arc from 6 meter. And this reduced snellen chart is used to access near point of accommodation 4. Near vision chart, which has 4 lines,having times Roman form, the standard spacing. And this near vision chart is used to access near point of accommodation. A Handle which hold by examiner. This video is just about different parts of the Royal air force ruler in next video we will discuss the proper procedure of the royal air force ruler.