Eye Shape and Focus

Your result, the one DNA position behind it, and what the research says.

6/10 confidence.

About Eye Shape and Focus

Whether you are nearsighted or farsighted is mostly a question of geometry. The eye focuses light at a fixed distance behind the lens, and if the eyeball grows slightly too long that focal point lands in front of the retina, making distant things blurry. Slightly too short and the opposite happens. PRSS56 is one of the genes regulating that growth during childhood, and this variant shifts it a little in one direction or the other. Time spent outdoors in daylight as a child affects eye growth strongly, and that effect is larger than this variant's.

Good to know: Nearsight and farsight are mostly about the eyeball's length, not the lens. Time outdoors in childhood influences eye growth strongly. The near-focus loss that arrives around forty is a different mechanism entirely.

Fun fact: Rates of nearsightedness have risen dramatically within a couple of generations, far too fast for genetics to explain, and time outdoors turned out to matter more than reading did.

Discovery: PRSS56 was linked to eye size through studies of families with unusually small eyes, then to ordinary refractive variation.

The Variant

The single variant behind this trait

Gene: PRSS56

Variant (rsID): rs1550094

Location: Chr 2:232,520,686

dbSNP rs1550094

The studies

Genome-wide association meta-analysis highlights light-induced signaling as a driver for refractive error (Tedja MS et al., Nature genetics, 2018)

Meta-analysis of 542,934 subjects of European ancestry identifies new genes and mechanisms predisposing to refractive error and myopia (Hysi PG et al., Nature genetics, 2020)

Other lifestyle traits

Burns or Tans: Three pigment genes that together set whether your skin answers sunlight by tanning or by burning.

Age Spots: A change in the promoter of the telomerase gene, linked to how many flat brown sun spots appear on skin over the years.

Hair Density: A change in a guidance receptor gene, linked in an East Asian study to how densely hair grows on the scalp.

Back to All Traits

Content updated September 2026.

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