You need to see an optometrist for this. It may just be the nature of your prescription but straight lines appearing bent can (very rarely so please don't panic!) be symptom of an eye condition called Macular Degeneration. Most common in older people, this condition has the power to destroy sight if it isn't caught early enough and damaged cells will never regenerate.
An anorthopia is an existence of a defect of vision in which straight lines appear to be curved.
A Circle
Light is a visible form of energy that travels in straight lines. It can also appear invisible, such as with ultraviolet or infrared light.
It may be that you were seeing pin cushion distortion; if you wear glasses then the lenses in the glasses aren't perfect and straight lines may appear slightly curved.
Latitude lines are parallel straight lines that run east-west, while longitude lines are not parallel to each other and appear curved when projected onto a map. Longitude lines converge at the poles and are widest at the equator.
One can write straight without lines by practicing good hand-eye coordination and using a steady hand to guide the pen or pencil in a straight path. This may require focus and patience to maintain a consistent writing direction.
On a polar projection, lines appear as straight lines that radiate outward from a central point (the pole). These lines represent constant latitudes, with the pole at the center of the map. The further away from the center, the greater the distortion in terms of shape and size.
Straight lines.
An apeirogon. Apeirogons are degenerate polygons that probably appear as never ending straight lines
When addressing a postcard without lines, write the recipient's name and address neatly in the center of the card. Use a ruler or straight edge to keep the lines straight, and make sure to leave enough space for the stamp and any additional information.
A polygon is a two dimensional shape bounded by straight lines. The moon is neither a plane shape (though it may appear as such), and it is clearly not bounded by straight sides.
you draw straight lines with a ruler