Fatshark DIY Diopters
I got this cheap pair of glasses from zennioptical.com for my exact prescription for $6.95. Fatshark dipoters cost $19.95 and do not come in my strength and don’t correct for astigmatism.”
I bought a Fatshark Attitude goggle set, but I am nearsighted and need about -3 correction in both eyes, plus I have astigmatism so I decided not to order the Fatshark Diopter set that they sell. The diopter set includes lenses for 3 different correction powers, -2, -4, and -6 so none of those is ideal for me and the image would look fuzzy. The diopters are just low quality simple correction lenses in a small rectangular shape designed to slide into a slot on the goggles in front of the viewing lens. This is the same thing as wearing glasses at the same time as wearing the goggles. Making my own diopters for my exact prescription will give me the best results for using the goggles.
So, I bought some cheap glasses with my optical prescription online at zennioptical.com for $6.95. I chose frames with large lenses and specified a wider pupillary distance so the center of the lens would give me plenty of room for cutting. The goal is to cut the lenses to fit the diopter slots the same as the Fatshark diopters, keeping the pupil in the center. I used a rubber vise and a dremel with cutting wheel to cut the lenses to size, and slot the sides so they properly fit into the mounting slots over the goggle lenses.
The results are as good as I’d hoped. I can now see the full image area in my goggles clearly sharply. The lenses stay in by themselves very well, but I may try some non-permanent way to glue them in, maybe a dot of rubber cement on an edge, just to be sure I don’t lose one.