The right bedside lamp lets you read without the bulb in your eyes (sample note).
Sit up in bed. The bottom of the shade should be close to your shoulder: on a standard bedside table that means a lamp of 40 to 55 cm. Lower, and the light falls on the table; higher, and you see the bulb.
Bring the height of your bedside table to the shop and we will try lamps against it.