Do Kittens’ Blue Eyes Stay Blue?

Kittens are born with a striking blue eye color that changes as they grow. The blue is not pigment but a structural effect that fades as melanin develops.

How and When Eye Color Changes

• Kittens’ eyelids stay fused shut until about 7 to 14 days old. When they first open, the iris has no melanin, so light scatters and the eye appears blue.
• Between 3 and 6 weeks, melanocytes in the iris begin producing melanin. By 6 to 8 weeks the adult color-green, gold, yellow, copper, or brown-usually becomes visible.
• The new color is fully stable by 3 to 4 months.

Genetics and Special Cases

• Some cats, such as Siamese or those with the dominant white gene, are genetically set to keep blue eyes for life.
• White cats with blue eyes have a high chance-up to 85%-of congenital deafness.
• Heterochromia, where a cat has two different colored eyes, is most often seen in white cats because the white coat gene can prevent pigment from reaching one iris.
• The gene for blue eyes is also linked to hearing, and studies suggest that permanently blue-eyed cats may have brain changes related to visual wiring.

Key takeaways

• Nearly all kittens start with blue eyes due to a lack of melanin.
• Eye color shifts between 3 and 6 weeks and stabilizes by 3 to 4 months.
• Blue eyes can persist permanently in certain breeds or genetic lines.
• White cats with blue eyes have a high risk of congenital deafness.
• Heterochromia is common in white cats.
• The blue-eye gene is associated with hearing and may affect brain wiring.

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Originally reported by iHeartCats. Read the full article.