"System failure?"

After referral from my optician, I was invited to the department surprisingly quickly for a timed anppointment and was seen for vision test and pressures test very quickly. But then I had to wait over two hours before being seen by a doctor. The department was very busy and I expected to be patient but it was only when I suggested to a member of staff that I thought I’d been forgotten that I was seen immediately by a doctor, when the examination and treatment was excellent. I wonder if there was a system failure that resulted in my having to wait so long for this treatment after arriving for a specifically timed appointment? It seems more a problem than just running late.