Descriptions of methods used to measure Essay Example | Topics and Well Written Essays - 1000 words

Descriptions of methods used to measure - Essay Example The PD can be read directly from the instrument. The near PD can be measured in a similar manner by adjusting the instrument for a reasonable reading distance (usually 40cm). Monocular PDs can also be taken with ease. Despite the fact that the pupilometer is the best way to measure PDs, not every doctor has a pupilometer readily available. Practicing the method outlined above is arguably the next best method. 2. Before telling the patient to look at his or her other eye, the doctor is to note what value is aligned with the centre of the patient's bridge of the nose. Let's say that this value is 30mm for example. This is the monocular PD for the right eye. 3. Finally the doctor directs the patient to look at his or her right eye and notices where the reflection lines up with the PD ruler. Let us say that this value is 62. To obtain the Monocular PD for the left eye, the doctor is to subtract the value obtained from the step 2, with the value obtained here (62-30= 32). The monocular PD for the patient's left eye is therefore, 32mm. 2. Then the doctor glances over and sees where the reflection in the patient's left eye aligns with the PD ruler without having the patient change their gaze. Finally the doctor subtracts this value with the value that corresponds with the centre of the bridge of the patient's nose. This is the near monocular PD. III. ... The PD can be read directly from the instrument. The near PD can be measured in a similar manner by adjusting the instrument for a reasonable reading distance (usually 40cm). Monocular PDs can also be taken with ease. Despite the fact that the pupilometer is the best way to measure PDs, not every doctor has a pupilometer readily available. Practicing the method outlined above is arguably the next best method. II. To distance monocular PD: 1. The doctor follows steps 1-4 for the total distance PD above. 2. Before telling the patient to look at his or her other eye, the doctor is to note what value is aligned with the centre of the patient's bridge of the nose. Let's say that this value is 30mm for example. This is the monocular PD for the right eye. 3. Finally the doctor directs the patient to look at his or her right eye and notices where the reflection lines up with the PD ruler. Let us say that this value is 62. To obtain the Monocular PD for the left eye, the doctor is to subtract the value obtained from the step 2, with the value obtained here (62-30= 32). The monocular PD for the patient's left eye is therefore, 32mm. Then, like in the previous method, the near monocular PD is measured: 1. The doctor follows steps 1 and 2 for distance monocular PD. 2. Then the doctor glances over and sees where the reflection in the patient's left eye aligns with the PD ruler without having the patient change their gaze. Finally the doctor subtracts this value with the value that corresponds with the centre of the bridge of the patient's nose. This is the near monocular PD. Recording (Distance PD in millimetres)/(Near PD in millimetres) = 64/60 For monocular PDs OD (Monocular