[Frequency and morphological change of double eyelid fold in relation to age]

The frequency of double eyelid fold and its morphological change were followed in 172 infants with cleft lip over the period from 0 to 5 years after birth. Change to double eyelid fold occurred 6 months after birth in 27 of them, at 6 months to 1 year in 20, at 1-3 years in 12 and at 3-5 years in 15. All showed double eyelid fold of the increasingly broadened type. A total of 1,844 residents in Hokkaido were also examined for the frequency and morphological change of double eyelid fold in relation to age-groups divided by decade of life, and actual measurement of double eyelid fold was carried out in 40 subjects. The frequency of double eyelid fold was 45% for those under 10 years of age, 57% for those 10-19 years old, 68% for those in their 20s, 69% for 30s, 76% for 40s, 79% for 50s, 81% for 60s and 57% for 70s. The increasingly broadened type was predominant in individuals under 30 years of age, whereas the parallel type became predominant in those in their 30s or older. The width of the double eyelid fold was 2.5mm when the eyes were open, accounting for 30% of the lid aperture, whereas it was 6.0 mm and accounted for 70% of the lid aperture when the eyes were closed.