Palpebral Fissure: This is the anatomically correct name of the parting in the middle of the lower and the upper eyelids. This opening lets light into the eye thru the cornea. It measures approximately 10 mm vertically and 30 mm horizontally. This separation may be compact in size horizontally due to William syndrome and also in “fetal alcohol syndrome”. The chromosomal situations known as Trisomy 21 and Trisomy 9 (Down Syndrome) may cause the palpebral fissure to be slanted upwards and Marfan Syndrome may be the cause of a downward slant. The fissure can be enlarged in height vertically in Grave’s disease, which is established as Dalrymple’s sign. This is one of the frequent symptoms of disorders that are genetic like Cri-du-chat.