I looked it up ( Gosky Adapter for Phone ).
Most reviews are for using with telescopes or binoculars to look at wildlife or for astronomy.
The 2 things that stopped me from ordering one right now were:
(1) Review for Microscope: "It's really difficult to get it set up right. On our microscope scope you really need to hold the phone further from the objective than this allows. Nobody in the lab uses it."
So I thought I would order it and see how it does with a microscope to photograph cells, & just return it if the images were bad or adapter was difficult to use. Buuuuuut...
(2) No Returns: " Terrible design squeezes the sides of the phone right where the buttons are located, making it useless for my OnePlus 5T. Further, the way it clamps onto the eyepiece is pretty weak and will not support a steady setup, even if it doesn't compress your phone's buttons as it does mine. I wanted to return this item but Gosky has a "gotcha" return policy. They never even responded to my return request. STAY AWAY from this bad product and disreputable seller."
I will see if I can find a different one that allows me to return the product though. I'll share if I find one.
Edit: Many of the 3rd party vendors on Amazon (if not all) do not offer free returns or even returns. I contacted Amazon (after reading they their epically long policies) - if you file a form called "A to z form" with your Amazon account, then Amazon sends you a box with prepaid postage so you can send it back, then Amazon refunds you. Customer service also said "usually a phone call to make a complaint, especially if you have Prime, is enough to get Amazon to refund you without having to file a form and send the item back". Coolio!
I’ve had a similar experience with cover slips but it hasn’t seemed to mess with anything. I use my phone up to the eyepiece for video with this type of adapter (can’t vouch for this exact one but mine is similar): https://www.amazon.com/Gosky-Universal-Phone-Adapter-Mount/dp/B013D2ULO6/ref=mp_s_a_1_9?crid=2KU8I82TGYS76&keywords=phone+microscope+attachment&qid=1671492909&sprefix=phone+microscope%2Caps%2C187&sr=8-9
Here’s a sample of video I’ve taken using iPhone XS zoomed in to fill the frame. I did edit the video to increase contrast so this is not straight out of phone but you get the idea: https://youtu.be/G4E08qnAfX4
We have the different sizes of these and they work pretty well through each scope, spotting scope, telescope and pair of binoculars we’ve used em on. Your mileage may vary.
Use an adapter like this. It will securely hold your phone in place over the eyepiece so you can take photos and videos.
Generic Gosky phone mount from Amazon https://www.amazon.com/Gosky-Universal-Phone-Adapter-Mount/dp/B013D2ULO6