Biol 2020 Lab
Case History Five
This case history is about a six month old boy who was taken to the doctor for his regular
check-up. His parents mention to the doctor that he often wakes up with a crusty right eye that
frequently tears up. The child has a blocked tear duct also known as Dacryostenosis.
My initial thoughts were that the baby has pink eye or a stye on his eye but as I kept
reading and saw that the childs eye is not red and usually infection free I knew it could not be
either of those things. The structures involved in creating tears and the pathway tears can take is;
tears are produced by the lacrimal gland and the accessory lacrimal glands and cover the cornea.
Tears then drain out the punctum in the medial eyelids, flow down the canaliculi into the
lacrimal sac. They then drain down the nasolacrimal duct into the nose at the inferior meatus
(under the inferior turbinate). I believe the child has a blocked tear duct. If a tear duct becomes
blocked or fails to open, tears cannot drain from the eye properly. The duct may fill with fluid
and become swollen, inflamed, and sometimes infected. What causes a blocked tear duct?
Causes of blocked tear ducts in children include: Failure of the thin tissue at the end of the tear
duct to open normally. This is the most common cause, infections, abnormal growth of the nasal
bone that puts pressure on a tear duct and closes it off and closed or undeveloped openings in the
corners of the eyes where tears drain into the tear ducts. Most of the time no treatment is
necessary and the blocked tear duct will clear up within the babies first year. If the duct remains
blocked after this time, the duct opening can be enlarged with a small probe. This may need to be
repeated, but this procedure is effective in most cases. Surgery may be an option after all other
treatments have been tried. The most common treatment for a blocked tear duct is gently