2*2 repeated measures ANOVA with an unbalanced number of observations

Hi everyone, sorry for this very basic question. I've trawled through previous pages and cannot quite find a case that corresponds to our situation.
320 individuals rated two types of films. The rating was provided on a 1-11 scale.There are many films of each type. In short the DV is a continuous variable.
20 individuals have a particular disease that we now consider of interest. We would like to examine the effect of the disease on the rating.
We conducted a 2-way repeated measures ANOVA, using 'situation type' as a within-subject factor, and 'disease status' as a between-subject factor, using SPSS. The design is obviously unbalanced with more observations in the healthy group. The data appeared to be normally distributed. Levine test suggested equality of variance. Does that mean it is appropriate to use ANOVA for this analysis?