Summary: Modelling of surgical time in cataract surgery
S.R. Brinkhof BSc1, Ir. M.E. Zonderland1,2, Prof. dr. R.J. Boucherie1, Dr. I.C. Notting3, Dr. F. Boer4, Dr. H.K. Hemmes5,
Prof. G.J.M. Luyten3
A cataract is a clouding of the human natural lens, the leading cause of
visual loss worldwide. Over time, the cataract can grow larger which
makes all-day activities such as driving and reading difficult. Surgery can
be performed in order to replace the human lens with a artificial plastic
lens. This is one of the most frequently performed surgeries worldwide.
Leiden University Medical Center (LUMC) registers all surgical times. For
cataract surgery, it is defined as the time from first incision to the last
closure of the eye. The distribution function of surgical times turned out
to be left-skewed and the question is what causes this skewness.
Possible actions a surgeon might perform in order to complete a surgery
are called surgical actions. The surgical process is modeled as a semi-
Markov process, with the state space representing all surgical actions. In
Figure 2, a part of the surgical process is depicted in graphical form.
Circles represent surgical actions and arrows possible transitions between
them. As indicated in the figure, there are different surgical paths to
complete the process.
Four staff surgeons and two resident surgeons were observed using a