Objective: 

Retinitis pigmentosa (RP) is the most common inherited progressive retinal neurodegenerative disease. Eleven patients with RP, after complete ophthalmic exploration, were studied by electrophysiological and morphological techniques.

Methods: 

Flash (ERG) and pattern (pERG) electroretinogram recordings and optical coherence tomography (OCT) images were obtained from the retina of the patients. Evaluation of the visual cortex was done by recording pattern reversal visual evoked potentials (VEPs).

Results: 

All of the patients, except one with reduced amplitude, had non recordable flash ERG. In 3 patients, pERG recordings were non detectable and 6 patients showed reduced amplitude and 2 had normal pERG. All patients had recordable VEPs. In 9 of them, the amplitude of the P100 was reduced in different extent. OCT images show the absence of the layer of photoreceptors in 3 patients and its presence only in macular region in 3 cases. In the rest, the photoreceptors layer was found throughout the retina. In 7 of the patients, other alterations of the retina, as macular oedema or epiretinal membrane, were observed. These results show first that VEPs can be obtained in patients with undetectable flash and pattern ERG and, what it is more interesting, in patients that showed absence of the photoreceptors layer by OCT exam. Secondly, retinal pathologies other than the alteration of the photoreceptor layer are commonly found in RP patients.

Conclusions: 

Our results point out the importance of performing a complete electrophysiological and morphological study to correct interpretation of the clinical aspect of RP and evaluation of the results from the different diagnostic tests.