Purchase this article with an account.
Vittoria De Rosa, Stefano Valente, Mariella Salomone, Erika Rigoni, Paolo Trabucco, Enzo Vingolo; Scotopic retinal function in patients with Usher syndrome. Invest. Ophthalmol. Vis. Sci. 2013;54(15):687.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine whether scotopic function measured by a dark-adapted microperimetry could be used as early marker of photoreceptor damage in patients with Usher syndrome. The purpose is to demonstrate that scotopic MP-1 can evidence retinal damage in early stages.
A MP-1 microperimetry according to Crossland et al. was performed in 10 healthy eyes(controls) and 10 eyes with Retinitis Pigmentosa with age between 20 and 50 year. All patients were fully dark adapted before testing and pupils were dilated with 1% tropicamide. Then we compared the results to classic microperimeter data (MP-1).
From the results analysis of the two types of Microperimetry it is clear that in patients with Usher syndrome, in either scotopic and photopic tests there is an annular peripheral scotoma, evidencing rod damage (peculiar alteration of Retinitis Pigmentosa). In scotopic(performed under dark adaptation) Mp-1, there is a further central scotoma, due to the normal exclusion of the cones activity in dark adaptation condition. Photopic treatment in controls showed a mean retinal sensitivity of about 19,76% in the central area and 19,94% in the peripheral zone, while in sick patients these values were respectively, 1,46% and 9,47%. Overall, scotopic test showed lower mean values, close to 0% in sick patients. However in the peripheral zone of these patients a minimum activity (0.02%) was recorded, likely demonstrating the presence of cones belonging to the group of s-cone.
Data show that microperimetry in scotopic conditions, allows to isolate the responses from stimulation of the rods and cones, recognizing directly scotomas. Furthermore eye-tracking system permits high reliable results even in uncooperative patients. According to our opinion an accurate diagnosis and follow-up for Retinitis Pigmentosa will be performed in next future, using this technique. Considering the reliability of this method it should be adopted for future therapeutic strategies.
This PDF is available to Subscribers Only