“What hand exercises are recommended for people working for long hours on the computer?”

To avoid hand strain from long hours on the computer, perform these exercises regularly:

Finger Stretches: Spread your fingers wide, hold for 5 seconds, then relax. Repeat 10 times.
Fist Clench: Make a fist, squeeze tightly, hold for 5 seconds, then release and spread your fingers. Repeat 10 times.
Thumb Stretches: Touch the tip of each finger to the tip of your thumb, forming an "O" shape. Repeat 10 times.
Wrist Flexor Stretch: Extend one arm in front, palm up. Gently pull back your fingers with the other hand, hold for 15-30 seconds. Repeat on the other hand.
Incorporate these exercises into your routine to reduce strain and enhance hand flexibility.

Wrist stretches and wrist/elbow AROM exercises are most appropriate. You want to focus on light exercises because your work is causing strain and you don't want to add excessive strain on top of your work. Hope this helps!

Stretching exercises for the wrist muscles to avoid carpal tunnel, also grip exercises.

I grip/Hercules grip available at Amazon. These are hand exercises which will help with strengthening hand muscles.

Stretch the forearm flexors and extensors frequently. You may also want to perform eccentric contractions of the extensor mass. A physical therapist will certainly be able to guide you through these so you don't injure yourself.

You should frequently change positions. I recommend getting up from the chair at least once every hour and taking a short stroll at least once every 2 hours. Now to address your hands, Stretch your fingers in both directions hold for 10 -15 seconds each. Also you should work on the extensors to reverse the stressors on the flexors, to do this place a rubber band around your fingers and simply open them against the resistance of the band. Good luck.