Abstract
Purpose: :
to analyse the fixation patterns in patients with Retinitis Pigmentosa (RP) submitted to Microperimetric (MP) examination.
Methods: :
20 patients, 40 eyes, with classic RP submitted to a complete ophthalmic examination and microperimetry were included in this retrospective study. Those with macular complications were excluded from the study. We used a MP-1 (NIDEK Technologies, Japan) for microperimetry, which was performed in all subjects with a red cross of 2° as the fixation target, white background illumination of 4 asb, Goldmann III stimuli with a projection time of 200 ms, and a customized grid of 68 stimuli around 10° centered on the fovea. The fixation pattern, stability, and fixation zone were classified according to Fuji et all.
Results: :
mean age was 49 years. 70% of eyes (N=28), corresponding to 14 patients, had stable and predominantly central fixation. 1 patient had unstable and predominantly eccentric fixation in both eyes. 1 patient had relatively unstable and predominantly central fixation. Instead, 4 patients reported a difference between the two eyes were examined: 2 of these had relatively unstable and predominantly central fixation in one eye and unstable and predominantly eccentric fixation in the other eye; 2 of these presented unstable and predominantly eccentric fixation in one eye and stable and predominantly central fixation in the other eye. The mean of fixation points of all the patients examined included into 2° is 74% and the 88% is included into the 4° central degrees.
Conclusions: :
In patients with RP without macular complications microperimetric study confirms that fixations are stable an predominantly central in the most of the patients even if visual field is reduced with low mean retinal sensitivity. Occurence of macular complications as cysts, epiretinal membrane and thinning could reduce retinal sensitivity and change fixations pattern.
Keywords: retinitis • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • eye movements