Critical that your desk lamp has an adequate amount of light otherwise you will get eye strain.

Agree, long term you will get major problems if you don't use a good desk lamp.

I recommend desk lamps that have multi-brightness levels, and directional (ie that you can point the head exactly where you want). 

I would recommend going for cool white colour temperature. Warm white makes you too sleepy but daylight white is too harsh.

Some modern lamps are dimmable - this is perfect for a study lamp.

As someone who has spent huge amount of time studying, I would state that lighting is absolutely critical. Make sure your light is bright - but not extremely so otherwise it will be gralry and harsh. Ideally light that is close to sunlight is best.

What ever light you choose, make sure you take regular breaks.

If you are going to study then make sure that the light part of the lamp is completely shaded, so you are not looking directly into any part of the globe. Very important advice if you want to avoid headaches.

It has been proven in studies that dim lighting - while causing eye strain - will not actually DAMAGE eyes. Nevertheless, if you are sudying, buy a high quality flexible desk lamp - it's worth its weight in gold.

The other alternative is to not have a lamp at all, as they can be very harsh - and instead using the ceiling light. Much more natural IMHO.