Retinal manifestations of Lafora disease

Abstract

Purpose : Lafora disease is progressive myoclonus epilepsy caused by accumulation of insoluble polyglucosan aggregates throughout the body. As central nervous system disorders often have ocular manifestations that might be utilized for more accurate characterization of disease progression, we sought to characterize the retina of individuals with Lafora disease using non-invasive retinal imaging.

Methods : One eye from each of three individuals with Lafora disease was imaged with adaptive optics scanning light ophthalmoscopy (AOSLO). Optical coherence tomography (OCT) volume and line scans were also acquired to assess total retinal thickness, ganglion cell-inner plexiform layer (GCIPL) thickness, and outer nuclear layer + Henle fiber layer (ONL+) thickness. OCT angiography (OCTA) scans were acquired at the macula and optic nerve head (ONH).

Results : Not all data acquired from each subject was analyzable due to intermittent myoclonic seizures and some fixational instability. Two subjects with previous seizure activity showed at least 4 regions of the ETDRS grid with retinal thickness at the bottom 5% of normal limits, while one subject with no apparent symptoms had normal retinal thickness. The asymptomatic subject and one symptomatic subject had GCIPL and ONL+ thicknesses that were within normal limits.¹ Foveal avascular zone area (OD: 0.33 mm², OS: 0.36 mm²) and acircularity (OD: 1.12, OS: 1.19) of the asymptomatic subject was similar to control data previously reported,² as well as ONH radial peripapillary capillary density in both eyes. All three subjects had parafoveal cone density estimates that were similar to previously published control data (Table 1).³ Nummular reflectivity puncta at the level of the RNFL were noted on AOSLO images in the macula and near the ONH in all three subjects.

Conclusions : We observed variable retinal structure measured with OCT, OCTA, and AOSLO in three individuals with Lafora disease, consistent with previous reports.⁴ Interestingly, nummular reflectivity within the inner retina on the AOSLO images was found in all three subjects. This phenotype does not appear to be associated with any particular disease but may represent a generalized neuro-degenerative process.^5
1PMID: 30398625
²PMID: 30280005
³PMID: 25515570
⁴PMID: 29907606
⁵PMID: 24894394

This is a 2020 ARVO Annual Meeting abstract.