LRRK2-associated Parkinson's disease patients have better stereopsis than idiopathic Parkinson disease.

OBJECTIVES

Visual dysfunctions are frequent and have several manifestations in idiopathic Parkinson's disease (PD). However, the characteristics of these complications in LRRK2 (leucine-rich kinase 2)-associated PD patients still lack systematic research. The purpose of this study is to assess visual functions of LRRK2-associated PD patients.

PATIENTS AND METHODS

Twenty-five (25) PD patients with LRRK2 R1628P and G2385R variants were included in the study and compared to 28 PD patients without these variants and 28 age-matched healthy controls. The genotypes of PD patients were kept double-blinded. Information on age, sex, disease duration, the movement disorder society-unified Parkinson's disease rating scale (MDS-UPDRS), Hoehn and Yahr staging scale (H&Y), Mini-Mental Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were included. Visual functions assessment included color perception, contrast sensitivity and stereopsis.

RESULTS

PD patients with or without LRRK2 R1628P and G2385R variants have declined contrast sensitivity, diminished color discrimination and damaged stereopsis. There was no significant difference in retinal level visual deficiency (color discrimination and contrast sensitivity) between PD with LRRK2 variants and those without, but cortex level visual function, i.e. stereopsis is better in PD with LRRK2 variants than non-carrier PD patients. The associated factors of stereopsis are different. The stereopsis is associated with MoCA scores independently in non-carrier PD patients, but with UPDRSIII scores in LRRK2-associated PD patients.

CONCLUSIONS

Visual functions are similarly affected in PD patients with and without LRRK2 R1628P and G2385R variants, but LRRK2-associated PD patients have better stereopsis than idiopathic PD patients.