Lacrimal system for undergraduates
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Transcript of Lacrimal system for undergraduates
By/Mohamed Ahmed El Shafie
Assistant Lecturer in ophthalmology department KafrELShiekh University
The lacrimal system consists of two parts:
Structures that secrete tear fluid.
Structures that facilitate tear drainage.LACRIMAL SYSTEM
It lies beneath the superior temporal margin of the orbital bone in the lacrimal fossa of the frontal boneIt is neither visible nor palpable A palpable lacrimal gland is usually a sign of a pathologic change such as dacryoadenitis or tumors.LACRIMAL GLAND ANATOMY
The tendon of the levator palpebrae muscle divides the lacrimal gland into a larger orbital part (two-thirds) and a smaller palpebral part (one-third).LACRIMAL GLAND PARTS
Several tiny accessory lacrimal glands (glands ofKrause and Wolfring) located in the superior fornix secrete additional seroustear fluid.ACCESSORY LACRIMAL GLAND
Tear Flow Physiology
may be due to one of two causes: Reduced tear production in certain systemic disorders (such as Sjgrens syndrome and rheumatoid arthritis) or as a result of atrophy or destruction of the lacrimal gland. Altered composition of the tear film due to vitamin A deficiency, medications (such as oral contraceptives), or certain environmental influences (such as nicotine smoking, or air conditioning). The tear film breaks up too quickly and causes corneal drying and scarring.DRY EYE
Patients complain of Burning, reddened eyes, and excessive lacrimation (reflex lacrimation) from only slight environmental causes such as wind, cold, low humidity, or reading for an extended period of time. A foreign body sensation is also present. May be accompanied by intense pain. Vision is usually minimally compromised .DRY EYE SYMPTOMS
Bitots spots: interpalpebral conjunctival foamy patches associated with severe vitamin A & xerophthalmia
FLUORESCEIN DYE DISAPPEARANCE TESTInstill 2 drops of fluorescein dye in the conjunctival sac and observe after 2 minutes
Normally no dye is seenProlonged retention of dye indicate inadequate drainage
JONES TEST IInstill 2 drops 2% fluorescein dye in the conjunctival sac, place a cotton bud dipped in 1% xylocaine in the inferior meatus, inspect the bud after 5 minutes.
Positive test- patent passages (may be hypersecretion)
No staining- Negative test
JONES TEST IIIf Jones I is negative, do Jones II
Place a bud similarly and perform lacrimal syringing
Positive test- lacrimal pump failure
Negative test- mechanical obstruction
DACRYOCYSTOGRAPHYTo visualize the passage and know the exact site, nature and extent of block.Inject radioopaque material in the sac.Take X-rays after 5 and 30 minutes
Congenital nasolacrimal duct obstruction
Delayed canalizationCan be bilateralReflux of purulent material from punctum
Acute inflammation of sac or pericystic area leading to acute pain, swelling, redness and watering from the eye.
No interference like syringing,probing etc.
Signs of acute dacryocystitis:Dry eyesPainless swelling Redness &Watering
Nasolacrimal duct opens-in the nose- at:Superior meatus Middle meatusInferior meatus