Eye problems, lethargy, and lack of appetite are tell-tale signs of a UVB deficiency. What UVB source was your friend using before and what is being used now? The truth is that most of the UVB bulbs on the market are crap and either do not offer sufficient UVB or cause eye problems.

Any compact bulbs, as sam said, are dangerous. In the past I have used fluorescent bulbs as well as mercury vapor bulbs, but with both you have to be careful about the brand.

To my knowledge the only fluorescent bulb that has not been associated with any eye problems is the ReptiSun 10.0. Fluorescent bulbs don't provide heat, so an additional heat source should be provided. They last 6 months and should be replaced every six months, regardless of whether they have burned out (UVB emission quits before visible light). If using a fluorescent UVB source you should be dusting the crickets with a calcium supplement that includes vitamin D3.
http://www.petmountain.com/product/r...-uvb-bulb.html

Mercury vapor bulbs are another option. They are much stronger than fluorescent bulbs and provide a large amount of heat. They need a "burn-in" period, should not be touched directly by your hands, should be replaced yearly, and need to be at least 12" away from the highest point in the cage. Also, it is important that, when using an MVB, calcium supplements do not include vitamin D3 as it may lead to an overdose. In terms of brands, I've heard good things about Powersuns and the type made by T-Rex, but I have always used Megarays and I love them. By far my favorite UVB option for beardies.
http://www.reptileuv.com/megaray-products.php
I would recommend having a look at the FAQ's page on the site; there's some great information there.

I don't mean to assume that this is the problem while it could be something else, but it really sounds to me like a UVB issue. And as there really isn't much good UVB info out there, it's a common problem.