Ophthalmology Notes @ OphthalNotes.blogspot.com

Ophthalmology Notes @ OphthalNotes.blogspot.com
A comprehensive collection of ophthalmology revision notes that cover a broad range of topics.

LACRIMAL SAC NOTES

                                                     SAC
ANATOMY-
2 parts-
1. Secretory part
2. Collecting part

Secretory part-
  1. LACRIMAL GLAND-
  • Superotemporal part of roof of orbit in the lacrimal fossa
  • LPS divides it into orbital & palpebral lobes
  • Tubulo-alveolar gland
  • N – 7 N

  1. GLANDS OF KRAUSE & WOLFRING-
UL-40-42
LL- 6-8

Collecting part /  Lacrimal passage-
  • 2 Lacrimal puncta –lie 6mm from inner canthus
  • 2 Canaliculi-2mm-vertical & 6-8mm horizontal
  • Lacrimal sac- lies in the lacrimal fossa
                         -15mm long
                         -5-6mm wide
                         -Part above the MPL- Fundus
*  Nasolacrimal duct-12-24mm long
                                -3-6mm wide
                                -2 parts-intraosseus & intrameatal
                                -Opens into inferior meatus of nose
*VALVE OF HASNER- at the lower end of NLD
                                     -Prevents air entry into the sac wen air is blown with a closed nose
* VALVE OF ROSENMULLER- at the opening of common
                                                         Canaliculus into the sac.
LAYERS OF TEAR FILM-
  1. Outer lipid layer- [Meibomian gland]
  2. Middle Aqueous layer [Lacrimal gland]
  3. Inner mucin layer [ Goblet cells,Gld of Henle,Gld of Manz]

PHYSIOLOGY OF LACRIMAL DRAINAGE-[D-05]
Tears secreted by the main & accessory lacrimal gland→Variable amount drained by evaporation & the remainder as follows-
  • Tears flow along the upper & lower marginal strips→enter upper &lower canaliculi by capillarity & suction.[70% drains-lower canaliculus]
  • With each blink→pretarsal orbicularis compresses the ampullae →shortens the horizontal canaliculi →puncta moves medially
  • Simultaneously,lacrimal part of orbicularis contracts & expands the sac→negative pressure→ sucks tears from canaliculi into the sac
  • When the eyes open→ms relax→sac collapses→ positive pressure→forces the tears down the NLD into the nose
  • Puncta move laterally→ canaliculi lengthen→ fill with tears

EPIPHORA-
Def- Overflow of tears d/t defect anywhere in the lacrimal drainage sys.
Causes-
  1. Ectropion
  2. Punctal stenosis/ occlusion
  3. Canalicular block
  4. NLD block
  5. Nasal polyp / tumour in inf meatus
  6. Lacrimal pump failure as in Bell’s palsy

LACRIMATION-
Def- Oversecretion  of tears without any defect in drainage sys.
Causes-
  1. Emotional /Psychological
  2. Irritation of conj / cor by dust, fumes etc
  3. Nasal irritation by any chem.
  4. Exposure to bright light.

WATERING IN CHILDN-
  1. conjunctivitis
  2. Cong dacryocystitis
  3. Buphthalmos.

CHRONIC DACRYOCYSTITIS-
COMPLICATIONS-
  1. Acute exacerbation of chr dacryocystitis
  2. From ac dacryocystitis-
  • Lacrimal abscess
  • Lacrimal fistula
  • Orbital / Facial cellulites
  • Cavernous sinus thrombosis
  • Lacrimal osteomyelitis
  1. Hypopyon cor ulcer

VIVA-Q. What is the dir of NLD?
  1. I PROBE LACRIMAL- Inferiorly-Posteriorly-Laterally

Q- Where does the NLD open ?
A-Inferior nasal meat

         DACRYOCYSTORHINOSTOMY [D-03]

INDICATIONS-
  1. NLD  block
  2. Chr dacryocystitis
  3. Mucocele

CONTRAINDICATIONS-
  1. Extreme old age
  2. Atrophic rhinitis
  3. Any growth in the sac
  4. Nasal polyps
  5. Hypertrophied inferior turbinate
  6. Dry eye syn
  7. blood dyscrasias
  8. Acute dacryocystitis
  9. Child < 3 yrs

PRE-OPER-
  1. Hb
  2. BT CT
  3. B. SUGAR
  4. BP
  5. ENT exam-atrophic rhinitis,nasal polyps,hypertrophied turbinates,DNS & malignancy
  6. NSAIDs & anticoag shud be stopped 3 days prior to surg
  7. Antibiotics & nasal decongestant drops 3 days prior to surg

TECH-
  1. Nasal packing-ribbon gauze soaked in xylocaine 2 % & adrenaline.Forcep shud be aimed at med canthus.Place the pack near the medial turbinate.Insertion of pack into post nasal cavity stimulates gag reflex & cannot achieve hemostasis.Never go superiorly & apply pressur→ damage the cribriform plate
  2. Anaesthesia- LA – adults & GA – childn & uncoop pts
  3. Skin Incision-8-10mm from medial canthus,2mm above the canthus & extending in a straight line for 3cm towards t.he ala of the nose . Avoid damage to the angular vein
  4. Expose the MPL & separate the ms fibres
  5. Expose the periosteum over the ant lac crest & reflect it
  6. Expose the lacrimal fossa & make initial bony puncture with blunt end of lacrimal dissector
  7. Enlarge the osteum with Citelli’s or Kerrison’s bone punch.[osteum is 15-17mm long,MPL to NLD]
  8. H- shaped incision is given on the sac  & nasal mucosa & ant & post flaps made
  9. Ant  & post flaps are sutured
10 Periosteum,orb & skin sutured

    COMPLICATIONS-
  1. Bleeding
  2. Wound gape
  3. Fistula
  4. Scar / keloid
  5. Closure of anastomosis [ failed DCR]
  6. Osteomyelitis
  7. Infection
  8. suture abscess

FAILED  DCR-
  1. Small osteotomy
  2. Blockage of anastomosis- improper suturing, redundant flaps,bony fragments,PO haematoma
  3. PO soft tiss inf
  4. Iatrogenic obstrn of common canaliculus

ENDONASAL DCR-
IND- Chr dacryocystitis with NLD block & mucocele

C/I-  Sac tumours
    -Dacryoliths

ADVANTAGES-
  1. No cutaneous scars
  2. Relatively bloodless surgery
  3. Less time
  4. Less edema
  5. Early recovery
  6. Medial canthal anatomy undistutbed
  7. BL DCR at the same sitting
  8. Can be done in acute dacryocystitis
  9. DCR can be combined with  septoplasty for DNS

DISADVANTAGES-
  1. High cost of instrument
  2. Steep learning curve
  3. Intranasal manipulation may be needed [ inferior turbinate #, septoplasty]

LASER ASSISTED DCR-
Best lasers- Holmium YAG laser,
                -  Diode laser

   DACRYOCYSTECTOMY-
   INDICATIONS-
  1. Old age
  2. Any growth in the sac
  3. TB of sac

    COMPLICATIONS-
   All of the above except 5
  1. incomplete removal→ rec chr dacryocystitis

                              PROBING
Should be done  bet 9-12 mo.
Prior to that ,spontaneous resolution is likely
Success rate decreases after the age of 1 year

Complications-
  1. Bleeding
  2. Failure to pass the probe d/t agenesis of NLD

Failure of probing twice is an indication for lacrimal intubation.
After the age of 3 yrs, DCR may be considered as bony dev is complete by then.


LACRIMAL GLAND TUMOURS-read from orbit
PLEOMORPHIC ADENOMA-
  • Also k/as mixed cell tum
  • Slow growing
  • Encapsulation [ not a true capsule but results from compression of adjacent tiss]
  • H/P- 2 components-1. Epithelial
                                    2 Stromal
T/T- En bloc excision
Principle-Avoid biopsy to avoid seeding & rec

 ADENOID CYSTIC CARCINOMA-
  • MC malignant lacrimal gld tum
  • Aggressive
  • Invades Ns→ painful
                          Intracranial spread
  • H/P-
Swisscheese pattern-Multiple lobules with pools of mucin
  • T/T
Exentration with removal of adjacent bone + Radiotherapy

Q- D/Ds of lac fossa mass-
1.Lac gld tum
2.sarcoidosis
3 Lymphoma

PLEOMORPHIC ADENOMA
ACC
Slow
Rapid
Painless
Painful
CT scan-Encapsulation &
Unencapsulated
            -bone erosion
Bone destruction

DRY EYE- notes

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