Reading strategies in normal subjects and in patients with macular scotoma-assessedby two new methods of registration

Reading is a complex sensorimotor process. Reading strategies under physiological and pathological conditions are examined by two new methods: (1) Eye movements during reading are recorded by an infrared limbus tracker (Ober2 system). The horizontal and vertical movements of both eyes are recorded simultaneously. Results are printed out as a graph. (2) Retinal fixation locus and eye movements during reading a text are simultaneously recorded by a modified scanning laser ophthalmoscope. The text is scanned onto the retina by a laser beam which is controlled by an acusto-optic modulator. This device allows for the first time a kinetic recording of the reading process, including morphologic, sensory and motoric findings simultaneously. Results can be recorded on a video tape. Both methods are very well supplementing each other and allow an integrative view of the reading process. Compared to normal subjects (n=10) the following parameters are impaired in patients with juvenile maculopathy (n =11): reading speed is decreased, number of saccades/line, of regressions and of horizontal corrective saccades is increased, vertical corrective saccades occur and fixation duration is irregular and prolonged. The significance of sensory findings for the reading ability and potential adaptive mechanisms, such as eccentric fixation are discussed. The analysis of the reading strategies offers a new approach to low vision rehabilitation.