It would be necessary to say right off that if these are something you see that are new you need a medical eye exam by, ideally, an Eye MD ophthalmologist or a non-MD optometrist. That being normal the most common thing that causes this are entoptic phenomena read the section in wikipedia.com it is especially good. The other thing that comes to mind when people see 'geometric' figures is eye or ophthalmic migraine which may or may not have headache. However they occur more in daylight than at night. Last for 10-30+ minutes and may have other migraine symptoms such as nausea, vomiting, headache, sensitivity to light and sound. they do not go away if you turn the lights on and can be seen with eyes closed. So if just in dark, you feel normal, goes away if you turn light on likely entoptic phenomena.
No because in the dark tear film problems are rarely symptomatic. They would be much more common day time and go away with blink or installation of artificial tears and don't have geometric designs.
rapid tear film break up is characteristic of what doctors call 'ocular surface disorder" but people call dry eyes. It is most characteristic of the lipid deficiency type.