Gecko hasn't been eating!! Blind? Parasite?

My gecko, Tarder Sauce, hasn't been eating like usual for the last week or two and he's started to lose weight (he was nice and plump before). I'm very concerned about him. Maybe parasites? Maybe not enough heat? I'm very new to this (I've had him for a month or two) but it's starting to get cold out.

he currently has a daytime lamp and a night lamp. The temp on the thermometer that's stuck in the cage says it's 80 degrees F during the day and like 60 at night with his night light. I try to keep my room at 70 degrees but it doesn't help much. He has a heating pad thing stuck to the bottom of the cage under where his house is. He has a reptile mat, and I took the plant thing out because he couldn't catch crickets with it in. He has one house that he stays in during the day. He has a bowl of water that I refill when needed (probably don't clean enough) and a dish of meal worms that he doesn't really touch. I used to feed him crickets primarily, but he can't catch them. I feel like he might be near sighted or lazy or blind. I made the mistake of keeping a few in the cage to see if he'd catch them and I read about them transferring parasites from his poop. The humidity on the cheap thermometer says 30%. I keep his dish filled with water and another with mealworms. Today he whipped his tail when he saw me.

I'm really worried that he's not eating or pooping much and losing weight. Any suggestions/tips would help very much! Sorry if this is a dumb question!

edited* I read that parasites are a big problem. I also read that having a daytime lamp that's not red can stress them out, so I'm going to buy a red heat lamp. I'm also going to try to crank up the heat to 90-95 with a higher intensity bulb(?) and switch out his water bowl to a small cap. I'm going to try wax worms to see if variety might help, and possibly feed him crickets with calcium dust by hand. Should I switch out his mat for play sand? What else can I do?

Ambient temp doesn't really matter all that much. Is your heat pad plugged straight into the wall or into a thermostat? If it's not in a thermostat it could be too hot. Measure the ground temp above the heat mat. It should be around 90. If the air is that hot it's too hot for him

Red heat lamp isn't the best choice. He needs an UTH with a warm spot close to 90 (you might need a dimmer or thermostat to get it this low) or he can't digest his food properly. Without a spot around this temperature geckos usually won't eat as they know its too cold to digest their food before it begins to rot in their stomach, which can make them really sick. The temperature needs to be measures on the floor of the cage, not the wall. The air temperature in the cage doesn't really matter as long as it doesn't drop below 65 degrees for more than a few hours at a time. If the temp in your house goes down to 60 I would get a Ceramic Heat Emitter (CHE) and use that instead of a light. I would also get rid of the lights on his cage as long as he is in a room that gets bright enough to read a book in for a few hours a day. I would switch out his mat to paper towels if it is not a kind that transmits heat well. I would stay away from sand.

agreed with whats been said. that picture is adorable :3

Testing for parasites is never a bad idea, and is not that costly. A vet will usually do a fecal for about $20, give or take a couple dollars, and will then require a visit if he is positive. At that point a little gecko-sized dose of something like Panacur shouldn't run you more than about $10. After the first round you will have to run at least two more fecals, weeks apart, to check that they are and remain clean. If not, repeat the anti-parasitic and check again.

Variety is always a good idea, maybe something new may peak his interest. Maybe some delicious butterworms may get his attention (and they're high in calcium)