Lateral Geniculate Nucleus Volume Assessment Using Linear Mixed Model in Moderate and Advanced Retinitis Pigmentosa

Purpose: We aimed to compare the volume of the lateral geniculate nucleus (LGN) in patients with different stages of retinitis pigmentosa (RP) with regard to age, sex and symmetry of the LGN. Methods: The investigated cohort included 13 patients with moderate (median Snellen visual acuity 0.75) and 18 patients with advanced (median Snellen visual acuity 0.06) RP-related visual field loss. The volumes of the left and right LGNs were manually measured using ITK-SNAP software after an examination of the brain with a 7 Tesla MRI. A linear mixed statistical model was used to assess LGN volume regarding age and gender of moderate and advanced RP patients and symmetry of both LGNs. Results: The mixed-effects linear model did not reveal a significant effect of disease group on LGN volume after adjusting for age and sex (F(1.27) = 0.01, p = 0.91). A significant effect of the LGN side was demonstrated, with the volume of the right LGN being significantly greater than that of the left (F(1.29) = 29.45, p < 0.001) in both disease groups, left-right. The interaction between disease group and LGN side was not statistically significant (F(1.29) = 0.45, p = 0.51). There is a tendency for LGN to decrease with age (F(1.27) = 3.84, p = 0.060), and there is no gender predilection (F(1.27) = 0.11, p = 0.74) in RP patients. There was correlation found between left LGN volume and visual acuity (ρ = 0.64) and central retinal thickness (ρ = 0.71) in the moderate group). Conclusions: No significant differences in LGN volume were found between patients with moderate and advanced RP. Furthermore, the volume of the right LGN was larger than the volume of the left LGN in RP patients, and this asymmetry is not gender-dependent. Correlation was found between the left LGN volume and visual acuity and central retinal thickness in moderate group. Our findings may have clinical implications for future RP management.