Senior-Loken syndrome (SLSN) is a very rare autosomal recessive oculo-renal disease characterized by the association of nephronophthisis (NPHP), a chronic kidney disease, with retinal dystrophy.

Visual impairment (or vision impairment) is vision loss (of a person) to such a degree as to qualify as an additional support need through a significant limitation of visual capability resulting from either disease, trauma, or congenital or degenerative conditions that cannot be corrected by conventional means, such as refractive correction, medication, or surgery.