For Spanish teacher Joyce Fortune, the deterioration of her eyesight could almost be an episode of House. In her case, what she could see did not actually match what doctors said she should be able to see.

For a lot of years it was just this big mystery, what was going on, why doesn’t she see what she’s supposed to see, and it was getting worse, said Fortune.

Eventually, her sight deteriorated to a point that she began using her pet Labrador, Gwen, as a guide dog. Fortune and her husband had had Gwen for seven years before training her as a service dog about a year ago.

Fortune has memorized the layout of her classroom: desks only four deep, the microwave in the back left, far right corner and special lights on the ceiling.

Along with her classroom, Fortune knows her neighborhood and the layout of the school so well that she does not need Gwen to show her around. Gwen only comes around when Fortuna is going somewhere new or unfamiliar.

Being in the classroom with a vision impairment poses some problems. Fluorescents give her a headache, so special lighting was specially installed by the district after a teacher walked in on Fortune grading papers in the dark.

If you ever want to see me go ballistic, then switch chairs… because I depend on them being where they need to be,” Fortune said.