What is Pupillary Distance (PD/IPD)?
The distance between your pupils centered is measured by the Pupillary Distance (PD). This measurement must be as accurate as possible because it determines where you are looking through the lens of your glasses or VR insert. The PD of an average adult is 54mm to 74mm whereas children’s PD falls between 43mm to 58mm.
How to Adjust the PD of Quest 2
It is indeed time to adjust the lenses once you've determined what distance works better for you. There is a link between them. You won't be able to move only left or right. To make things easier, we suggest moving both eyes at the same time to avoid accidentally damaging lenses that are somewhat sensitive.
If you look at your headset, you'll notice that either one or both sides of the lenses have a gap in the plastic enclosure. This makes it possible for the lenses to move back and forth. Set the headset down with the lenses facing up to quickly adjust them to your desired position. Then, push on the outside of the lenses (not the glass) with your thumb. Now move them softly but firmly.
The Quest 2 lets users to modify the lenses' actual position on the headset, unlike its predecessor. The headset, for example, can be modified to fit individuals with different eye distances by simply changing the distance between the lenses. There are three different setting distances available on the Quest 2: 58mm, 63mm, and 68mm.
Single PD vs Dual PD
A single PD is the distance between the centers of two pupils, which can be either a distance or a near PD. Any prescription glasses, excluding reading glasses, can be ordered using distance PD. To calculate near PD for reading glasses, follow the steps below.
On the other hand, dual PD, also known as monocular PD, is the distance between the centers of each pupil and the bridge of the nose. 32/30 is the standard notation for dual PD. The right eye (OD) measurement is always the first number, while the left eye (OS) measurement is always the second number.
How Do You Calculate Near PD For Reading Glasses?Subtract 3mm from your distance PD to get Near PD for reading glasses. For instance, if your distance PD turned out to be 63mm, your near PD would then be 60mm.
Ways to measuring the PD accurately
1. By an optician
Contacting an optician and having them measure your PD for you is the most accurate way to do so.
2. Measure your PD with the help of a friend
1. Keep both of your eyes open.
2. Place the millimeter ruler's zero over the middle of one of your pupils.
3. Calculate the distance between the two pupils' centers.
Tips to get an accurate measurement
• Have them crouch or sit while you stand, so they're out of your line of sight.
• Try to keep your eyes as still as you can.
• Look 10ft to 20ft above him.
• Avoid looking at the person doing the measuring!
• Measure 2-3 times to ensure accuracy.
3. Measure your PD by yourself
Use a ruler and a mirror. To begin, position the 0 precisely beneath your left pupil. Then, while looking straight ahead, calculate the distance between your right pupil and your left pupil. It may be beneficial to close your left eye right after adjusting the 0 to ensure that you can see absolutely straight ahead.
Why PD Matters for VR?PD is important in VR for two key reasons.
The first reason why PD is important is that the lens's optimal focal point should be aligned directly with your pupils. This guarantees that the image for that headset is as sharp as possible. The second reason is related to stereoscopic vision.
There are two ways in which we perceive depth. Monocular cues are a scene's elements that use only one eye to inform your brain about size and distance. Forced perspective is a method used in movies like The Lord of the Rings to take the use of monocular cues and deceive us into thinking something is bigger or smaller than it is.
Stereoscopic cues need both eyes and depend on the minor difference in the image perceived by each eye. To simulate the effect of depth perception, 3D media, whether in a cinema or in virtual reality (VR), generates two slightly different images.
Your brain is designed to conduct the 3D calculation for your own PD because everyone's PD is different. Your depth perception will be inaccurate if the VR headset uses the incorrect PD when computing what to display to each eye. As your eyes strive to adjust to this strange situation, you may experience eye strain.
Another reason to know your PD is that it can be outside the PD range for some headsets. In that way, you don't have to waste money on VR headsets that won't work for you. The PD range for the Oculus Quest 2 is 58mm to 68mm. These are divided into three lens positions that can be switched quickly. If you are outside of this range, a fully clear image may not be attainable.
This is why, in VR, measuring your PD is vital, but we must first undertake the effort of measuring it.
Your PD should most likely be in the setting where the text appears to be the sharpest and the clearest. The current setting should be provided in headsets with physical PD. Therefore, if you find a setting that suits you, you can use this number for other headsets as well.