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Seminar 1 ophthal refractive error and cataract

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  • 1. REFRECTIVE ERROR AND CATARACT
    Ng Boon Keat, MohdHanafi, AnandKumar
  • 2. PART 1: REFRECTIVE ERROR
  • 3. EMMETROPIA
    The state of refraction of the eye in which parallel rays, when the eye is at rest, are focused exactly on the retina.
    Stedman’s Medical Dictionary, 2005
    3/59
  • 4. EMMETROPIA
    Eye with no refractive error
    Parellel light = light from infinity (light from far far away)
    Images are focused with relaxed lens and cornea
    Without the need for accommodation
    ABC of Eyes, 2004
    4/59
  • 5. MYOPIA
    That optic condition in which parallel light rays are brought by the ocular media to focus in front of the retina.
    Synonym:
    Shortsightedness
    nearsightedness.
    Stedman’s Medical Dictionary, 2005
    5/59
  • 6. MYOPIA
    Pathophysiology
    globe too long relative to refractive mechanisms, or refractive mechanisms too strong
    light rays from distant object focus in front of retina blurring of distant vision
    Toronto notes: Ophthalmology, 2006
    6/59
  • 7. MYOPIA
    Clinical features:
    usually presents in 1st or 2nd decade, stabilizes in 2nd and 3rd decade; rarely begins after 25 years except in diabetes or cataracts
    blurring of distance vision; near vision usually unaffected
    Complications:
    retinal tear/detachment, macular hole, open angle glaucoma.
    Toronto notes: Ophthalmology, 2006
    7/59
  • 8. CORRECTIONS
    • ABC of Eyes, 2004
    8/59
  • 9. HYPERMETROPIA
    An ocular condition in which only convergent rays can be brought to focus on the retina.
    Synonym:
    Hyperopia
    Farsightedness
    Stedman’s Medical Dictionary, 2005
    9/59
  • 10. HYPERMETROPIA
    Pathophysiology:
    globe too short relative to refractive mechanisms, or refractive mechanisms too weak
    light rays from distant object focus behind retina  blurring of near +/-distant vision
    Toronto notes: Ophthalmology, 2006
    10/59
  • 11. HYPERMETROPIA
    Clinical features:
    youth: usually do not require glasses (still have sufficient accommodative ability to focus image on retina)
    30s-40s: blurring of near vision due to decreased accommodation, may need reading glasses
    >50s: blurring of distance vision due to severely decreased accommodation
    Complications:
    angle-closure glaucoma, particularly later in life as lens enlarges
    Toronto notes: Ophthalmology, 2006
    11/59
  • 12. CORRECTIONS:
    • ABC of Eyes, 2004
    12/59
  • 13. PRESBYOPIA
    The physiologic loss of accommodation in the eyes in advancing age.
    Stedman’s Medical Dictionary, 2005
    13/59
  • 14. PRESBYOPIA
    Pathophysiology
    hardening/reduced deformability of the lens results in decreased accommodative ability
    near images cannot be focused onto retina (focus is behind retina as in hyperopia)
    Normal aging process (especially over 40 years)
    Toronto notes: Ophthalmology, 2006
    14/59
  • 15. PRESBYOPIA
    Clinical Features:
    if initially emmetropic, person begins to hold reading material further away, but distance vision remains unaffected
    if initially myopic, person begins removing distance glasses to read
    if initially hyperopic, symptoms of presbyopia occur earlier
    Corrections:
    Usually as same as treatment of hypermetropia
    Toronto notes: Ophthalmology, 2006
    15/59
  • 16. APHAKIA
    Absence of the lens of the eye.
    Stedman’s Medical Dictionary, 2005
    A state of having no lens (eg removed because of cataract surgery)
    Oxford Handbook of Clinical Specialties, 2009
    16/59
  • 17. APHAKIA
    Clinical features:
    Removal of lens will result hypermetropic refractory error
    Corrections:
    Glasses
    Contact lens
    Secondary intraocular lens implant
    ABC of Eyes, 2004
    17/59
  • 18. INTRAOCULAR LENS IMPLANTS
    • ABC of Eyes, 2004
    18/59
  • 19. CATARACT GLASSES
    • ABC of Eyes, 2004
    19/59
  • 20. ACCOMMODATION
    • ABC of Eyes, 2004
    Component of accommodation:
    Pupil Constriction
    Ciliary muscle contraction and globular changes of the lens
    Convergence of the eyes
    20/59
  • 21. PART 2: CATARACT
  • CATARACT: DEFINITION
    A cataract is clouding of the lens of the eye, which impedes the passage of light. Most cataracts are related to ageing, although occasionally children may be born with the condition, or cataract may develop after an injury, inflammation or disease.
    -WHO-
    Any opacity of the crystalline lens
    22/59
  • 27. CATARACT: TYPES
    23/59
  • 28. CATARACT: DEVELOPMENTAL
    24/59
  • 29. CATARACT: CONGENITAL
    25/59
  • 30. CATARACT: SENILE
    • Increasing nuclear opacification
    • 31. Exaggeration of normal nuclear
    ageing change
    • Initially yellow then brown
    • 32. Causes increasing myopia
    26/59
  • 33. CATARACT: SENILE
    27/59
  • 34. CATARACT: SENILE
    MK
    28/59
  • 35. CATARACT: SENILE
    MK
    29/59
  • 36. CATARACT: SENILE
    30/59
  • 37. CATARACT: TYPES
    31/59
  • 38. CATARACT: TYPES
    32/59
  • 39. Juvenile
    Adult
    • White punctate or snowflake
    posterior or anterior opacities
    • Cortical and subcapsular
    opacities
    • May progress more quickly than
    in non-diabetics
    • May mature within few days
    DIABETES MELLITUS
    33/59
  • 40. Atopic dermatitis
    Myotonic dystrophy
    • Stellate posterior subcapsular opacity
    • 41. Anterior subcapsular plaque
    (shield cataract)
    • 90% of patients after age 20 years
    • 42. Other type – posterior subcapsular
    • 43. No visual problem until age 40 years
    34/59
  • 44. Concussion
    Causes of traumatic cataract
    ‘Vossius’ ring from
    imprinting of iris pigment
    Flower-shaped
    Penetration
    Other causes
    • Ionizing radiation
    • 45. Electric shock
    • 46. Lightning
    35/59
  • 47. CATARACT: AETIOLOGY
    36/59
  • 48. CATARACT: SYMPTOMS
    37/59
  • 49. CATARACT: SIGNS
    ↓visual acuity
    Diminished red reflex
    Change in lens appearance
    Normal perception of light
    Pupillary reflexes normal
    Slit lamp examination allows the cataract to be examined in detail
    38/59
  • 50. TEMPORARY MANAGEMENT
    Not the definitive management
    Cannot slow the progression
    May in the end have to go for surgery anyway
    39/59
  • 51. TEMPORARY MANAGEMENT
    UV blocking sunglasses
    Change of spectacles correction
    Instilling dilating drops
    Anti-oxidant vitamin intake
    Avoiding smoking - smoking accelerates cataract development
    Increase lighting especially when reading - illumination from above & behind
    Routine eye examination - esp. when having certain diseases and taking drugs (eg.steroids, chlorpromazine )
    (Only preventive, does not treat cataract)
    40/59
  • 52. DEFINITIVE MANAGEMENT
    Extracapsular Cataract Extraction (ECCE)
    Phacoemulsification
    Intracapsular Cataract Extraction (ICCE)
    (All these are followed by intraocular lens implantation)
    41/59
  • 53. INDICATION FOR SURGERY
    1) Visual impairment
    varies from person to person-depends on the location of the opacity.
    2) Medical indications
    presence of cataract adversely affecting health of eye (eg. phacolytic glaucoma, secondary angle closure by an intumescent lens & diabetic retinopathy)
    3) Cosmetic indication
    mature cataract in a blind eye removed to restore a black pupil.
    42/59
  • 54. PREOPERATIVE ASSESSMENT
    Cardiovascular
    Hypertension (orbital haemorrhage, suprachoroidal expulsive haemorrhage)
    Heart rate (suprachoroidal expulsive haemorrhage)
    Anticoagulant
    Posture
    difficult if orthopnoea or kyphoscoliosis
    Ocular of eye
    cornea focusing power
    length
    43/59
  • 55. EXTRACAPSULAR CATARACT EXTRACTION (ECCE)
    Incision is made in the eye
    Anterior capsule is open
    Nucleus is expressed and soft lens fibres aspirated
    Non-folding lens is inserted into the lens bag
    Incision closed with fine sutures
    44/59
  • 56. ECCE
    45/59
  • 57. PHACOEMULSIFICATION
    Make a small tunnel incision is made(3 mm) in the eye
    Circular hole is made in anterior capsule of lens.
    Ultrasonice probe-liquefy the hard nucleus
    Remaining soft lens fibre was aspirated
    A folded replacement lens inserted .
    46/59
  • 58. PHACOEMULSIFICATION
    47/59
  • 59. INTRACAPSULAR CATARACT EXTRACTION (ICCE)
    Removal of entire lens together within its capsule with a cryoprobe,
    suspensory ligaments of the lens have been dissolved ( -chymotrypsin ).
    bigger incision and slow to heal (around 6 weeks)
    Higher incident of retinal detachment (vitreous prolapse)and cystoid macular oedema
    used when facilities for extracapsular surgery are not available.
    48/59
  • 60. INTRAOCULAR IMPLANTS
    Consists of central the lens in position biconvex optic & two legs/haptic to maintain
    Types of IOL:
    1) Polymethylmethacrylate
    (PMMA)
    2) Silicone
    49/59
  • 61. INTRAOCULAR IMPLANTS (CONT.)
    Posterior chamber lens - placed in the empty lens bag.
    Anterior chamber lens - fixed in the angle of the anterior chamber of the eye.
    “Pupil clip” lens - clipped to the margin of the iris.
    50/59
  • 62. COMPLICATIONS OF CATARACT SURGERY
    Operative complications
    • Vitreous prolapse-may cause retinal detachment
    • 63. Suprachoroidal (expulsive) haemorrhage
    2. Early postoperative complications
    • Iris prolapse
    • 64. Striate keratopathy
    • 65. Acute bacterial endophthalmitis-emergency.
    • 66. Uveitis-prone in pt with DM and previous ocular inflammtrydx.
    51/59
  • 67. 3. Late postoperative complications
    • Capsular opacification
    • 68. Implant displacement
    • 69. Corneal decompensation
    • 70. Retinal detachment
    • 71. Chronic bacterial endophthalmitis
    52/59
  • 72. ACUTE BACTERIAL ENDOPHTHALMITIS
    incidence - about 1:1,000
    common causative organism : Staph. epidermidis,Staph aureus, Pseudomonas sp.
    Source of infection :
    - patient’s own external bacterial flora is the most frequent culprit
    - contaminated solutions and instruments
    - environmental flora including that of the surgeon and operating room personel
    53/59
  • 73. Signs of mild endophthalmitis
    - mild pain and visual loss
    - hypopyon in anterior chamber
    - fundus visible with indirect ophthalmoscope
    signs of severe endophthalmitis
    - pain & marked visual loss
    - corneal haze, fibrinousexudate and hypopyon
    - absent or poor red reflex
    - inability to visualize fundus with indirect opthalmoscope
    54/59
  • 74. DIFFERENTIAL DIAGNOSIS
    1) Uveitis associated with retained lens material
    - no hypopyon present
    2) Sterile fibrinousexudate
    - no pain and few if any anterior cells
    - posterior synechiae may develop
    55/59
  • 75. MANAGEMENT OF ACUTE ENDOPHTHALMITIS
    1. Preparation of intravitreal injections
    2. Identification of causative organisms
    • Aqueous samples
    • 76. Vitreous samples
    3. Intravitreal injections of antibiotics
    4. Vitrectomy – only if VA is PL
    5. Subsequent treatment
    56/59
  • 77. 1. Periocular injections
    • Vancomycin 25 mg with ceftazidime 100 mg
    or gentamicin 20 mg with cefuroxime 125 mg
    • Betamethasone 4 mg (1 ml)
    2. Topical therapy
    • Fortified gentamicin 15 mg/ml and vancomycin 50 mg/ml
    drops
    • Dexamethasone 0.1%
    3. Systemic therapy
    • Antibiotics are not beneficial
    • 78. Steroids only in very severe cases
    SUBSEQUENT TREATMENT
    57/59
  • 79. CHRONIC BACTERIAL ENDOPHTHALMITIS
    signs:
    - late onset, persistent, low-grade uveitis- may be granulomatous
    - commonly caused by P. acnes or Staph. epidermidis
    - low virulence organisms trapped in capsular bag
    Rx:
    - initially good response to topical steroids
    - recurrence after cessation of treatment
    - inject intravitrealvancomycin
    - remove IOL and capsular bag if unresponsive
    58/59
  • 80. THANK YOU