27 May 2013
We read with great interest the article by Moreno and colleagues . The authors should be congratulated on enlarging our knowledge on retinal nerve fiber layer (RNFL) thickness measurements in Alzheimer’s disease (AD) and other types of dementia. The results of this study show that optical coherence tomography (OCT) seems to be a useful tool for diagnosing dementia syndromes but does not seem to contribute to the differential diagnosis of different types of dementia. Nevertheless, we believe that some supplementary discussion of the problem is needed. Although the authors stated in their article that there were no studies on the RNLF thickness in non-AD dementias, in fact there were two studies on RNFL thickness in a type of dementia different from AD; we refer to the CADASIL syndrome (Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), considered a genetic form of small-vessel disease causing subcortical dementia. Thus, in 2007, Parisi et al.  reported a reduction of peripapillary RNFL thickness in six CADASIL patients. According to the authors, this morphological abnormality could be ascribed to an impairment of the retinal vascular supply leading to a global neuroretinal involvement. Recently, Rufa et al.  confirmed a decreased RNFL thickness in seventeen CADASIL patients with respect to controls, although no significant correlations were found between RNFL thinning and brain atrophy.
Andrzej Grzybowski1,2, Francisco J. Ascaso3,4
1Department of Ophthalmology, Poznan City Hospital, Poznań, Poland
2Chair of Ophthalmology, University of Warmia and Mazury, Olsztyn, Poland
3Department of Ophthalmology, ”Lozano Blesa” University Clinic Hospital, Zaragoza, Spain
4Aragon Health Sciences Institute, Zaragoza, Spain
 Moreno-Ramos T, Benito-Leon J, Villarejo A, Bermejo-Pareja F (2013) Retinal nerve fiber layer thinning in dementia associated with Parkinson's disease, dementia with Lewy bodies, and Alzheimer's disease. J Alzheimers Dis 34, 659-664.
 Parisi V, Pierelli F, Coppola G, Restuccia R, Ferrazzoli D, Scassa C, Bianco F, Parisi L, Fattapposta F (2007) Reduction of optic nerve fiber layer thickness in CADASIL. Eur J Neurol 14, 627-631.
 Rufa A, Pretegiani E, Frezzotti P, De Stefano N, Cevenini G, Dotti MT, Federico A (2011) Retinal nerve fiber layer thinning in CADASIL: an optical coherence tomography and MRI study. Cerebrovasc Dis 31, 77-82.