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OP10 Ophthalmology Lacrimal Apparatus Toronto Notes 2019 Lacrimal Apparatus
Long-term use of artificial tears with preservatives should be avoided when treating dry eyes
Excessive tearing can be caused by dry
eyes – if the tear quality is insufficient, “reflex tearing” may occur
• tearfilmmadeupofthreelayers
■ outer oily layer (reduces evaporation): secreted by the Meibomian glands
■ middle watery layer (forms the bulk of the tear film): constant secretion from conjunctival glands
and reflex secretion by lacrimal gland with ocular irritation or emotion
■ inner mucinous layer (aids with tear adherence to cornea): secreted by conjunctival goblet cells
• tearsdrainfromtheeyesthroughtheupperandlowerlacrimalpuncta→superiorandinferiorcanaliculi → lacrimal sac → nasolacrimal duct → nasal cavity behind inferior concha (Figure 3)
Dry Eye Syndrome (Keratoconjunctivitis Sicca)
Definition and Etiology
• aqueous-deficient
■ Sjögren syndrome (autoimmune etiology e.g. RA, SLE)
■ non-Sjögren syndrome (idiopathic age-related disease; lacrimal gland scarring e.g. trachoma;
decreased secretion e.g. contact lenses, CN VII palsy, anticholinergics, antihistamines, diuretics,
β-blockers)
• evaporative(normallacrimalfunction,excessiveevaporationofaqueouslayer)
■ Meibomian gland dysfunction (posterior blepharitis)
■ vitamin A deficiency (xerophthalmia with goblet cell dysgenesis)
■ eyelid abnormalities e.g. ectropion, CN VII palsy (decreased blinking) ■ topical ocular medications with preservatives
■ contact lenses, allergic conjunctivitis
• mixedetiologiesarecommon
Clinical Features
• dryeyes,redeyes,foreignbodysensation,blurredvision,tearing
• slit-lampexam:decreasedtearmeniscus,decreasedtearbreak-uptime(normallyshouldbe10s),
punctate staining of cornea with fluorescein
Investigations
• surfacedamageobservedwithfluorescein/RoseBengalstaining • decreaseddistanceinSchirmer’stest
Complications
• erosionsandscarringofcornea
Treatment
• medical:preservative-freeartificialtearsuptoq1handointmentatbedtime(preservativetoxicity becomes significant if used more than 4-6x/day), short course of mild topical corticosteroid, omega-3 fatty acids orally, and eyelid hygiene for blepharitis
■ for moderate cases, cyclosporine ophthalmic emulsion 0.05% (Restasis®) can be used
• procedural:punctalocclusion(punctalpluginsertion),lidtaping,tarsorrhaphy(sewlidstogether)if
severe
• treatunderlyingcause
Epiphora (Excessive Tearing)
Etiology
• emotion, pain
• environmentalstressor(cold,wind,pollen,sleepdeprivation)
• lid/lashmalposition:ectropion,entropion,trichiasis
• inflammatory:conjunctivitis,dacryoadenitis,uveitis,keratitis,cornealforeignbody
• dryeyes(reflextearing)
• lacrimaldrainageobstruction(congenitalfailureofcanalization,aging,rhinitis,dacryocystitis) • paradoxicalgustatorylacrimationreflex(crocodiletears)
Investigations
• usingfluoresceindye,examineforpunctalrefluxbypressingoncanaliculi
• Jonesdyetest:fluoresceinplacedinconjunctivalcul-de-sac,andcottonapplicatorplacedinnoseto
detect flow (i.e. rule out lacrimal drainage obstruction)
Treatment
• lidrepairforectropionorentropion
• eyelashremovalfortrichiasis
• punctalirrigation(dilationandirrigation)
• nasolacrimalductprobing(infants)
• tubeplacement:temporary(Crawford)orpermanent(Jones)
• surgical:dacryocystorhinostomy–forminganewconnectionbetweenthelacrimalsacandthenasalcavity