Abstract
Purpose: :
To assess by Optical Coherence Tomography (OCT) the retinal nerve fiber layer (RNFL) thickness of unaffected carriers from a previously reported very large Brazilian pedigree (SOA–BR) with homoplasmic11778 Leber’s hereditary optic neuropathy.
Methods: :
39 carriers (mean age: 39.0±13.7 years) (16 males and 23 females) belonging to the same Brazilian maternal lineage (SOA–BR family) of Italian ancestry were compared to an age matched control group of 35 Brazilian individuals (16 males and 19 females). Stratus OCT was used to detect the peripapillary RNFL thickness (3.4mm diameter). One randomly selected eye was considered for each carrier and control individual. Groups were compared by one–way ANOVA analysis of variance.
Results: :
RNFL analysis of unaffected male carriers showed a significant thickening of the temporal quadrant with respect to controls (P= 0.0017). RNFL thickness of unaffected female carriers was similar to the control group, with no statistically significant differences in any quadrant.
Conclusions: :
Our study showed that the peripapillary RNFL is thickened in the unaffected male carriers belonging to the SOA–BR maternal lineage. In males this alteration, selectively involving the small fibers of the papillomacular bundle, was limited to the temporal quadrant. These findings suggest the occurrence of axonal swelling, which may indicate an early stage of RNFL damage in absence of clinical symptoms. The follow up of unaffected carriers will validate the possible use of this finding as pre–clinical predictor warning the onset of acute disease and visual loss.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina: proximal (bipolar, amacrine, and ganglion cells) • neuro-ophthalmology: optic nerve