Cataract Flashcards by Seb AT

What is a Cataract?

Progressive cloudiness of the lens causing gradual vision loss and blindness if untreated.

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What is the most common type of cataracts?

Age-related.

1 - Nuclear
2 - Cortical
3 - Posterior Subscapular.

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What Grades are used to describe cataracts?

Immature - Partially opaque
Mature - Completely opaque
Hypermature - Shrunken anterior capsule due to leakage of material outside the lens.
Morgagnian - A form of hyper mature cataract with liquefaction to the cortex.

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Describe a Nuclear Cataract?

Cloudiness of the nucleus, the central portion of the lens.

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Describe a Cortical Cataract?

Swelling of the cortex causing spokes/wedge-like peripheral cloudiness.

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Describe a Posterior subcapsular Cataract?

Opacity in the posterior capsule of the lens

Seen in younger individuals, steroid users, and diabetics.

Most visually significant and quick progression.

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Most common source of organisms leading to post-operative endophthalmitis?

Most likely causative organism?

Patient’s lids (Own periocular flora)

Staphylococcus Epidermidis

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What medication increases risk of complications during cataract surgery?

Doxazosin

or other A1-Angonists (Tamulosin) -> May cause intraoperative floppy iris syndrome

Intracameral phenylephrine can be used to dilate pupils in high risk patients.

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What steps are recommended post cataract surgery to prevent post-cataract endophthalmitis?

Pre-operatively?

Sub-conjunctival injection of antibiotic at the end of surgery.

Using Iodine to clean patients eyes

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Explain second sight phenomenon?

When there is a temporary change in vision during early cataract development. Before vision deteriorates, vision, especially close-up reading vision, improves significantly.

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Main symptoms of Nuclear cataracts ?

Reduced VA, Myopic shift (Increasing myopia), dullness of colour.

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What is the characteristic feature of cortical cataracts?

Glare with bright lights / halos when driving at night.

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Explain the nature of cortical cataracts?

Opacification fo the lens cortex causing wedge shaped opacities.

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Associated conditions with cortical cataracts?

Alport syndrome- Anterior lenticonus with cortical cataract.

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Types of subcapsular cataracts?

Anterior - Opacities under the anterior capsule.

Posterior - Patients complain of glare and pdifficulty seeing in bright lights and near vision

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What causes of acquired posterior subcapsular cataract?

Corticosteroids
Diabetes (snowflake shaped) 
Retinitis pigmentosa 
NF2
Chloroquine

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What causes of acquired posterior subcapsular cataract?

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Blunt Trauma (FLOWER-SHAPED)
Atopic dermatitis (SHEILD-LIKE)
Wilsons (SUNFLOWER)
Infrared radiation (GLASS-BLOWER)
Post congestive angle closure glaucoma (GLAUKOMFLECKEN)
Gold

ASSOCIATED CONDITION?

BLUE DOT CATARACT

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Downs syndrome

ASSOCIATED CONDITION?

CHRISTMAS TREE LIKE CATARACT APPEARANCE

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MYOTONIC DYSTROPHY

ASSOCIATED CONDITION?

POLYCHROMATIC CATARACT- TREE LIKE APPEARANCE

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HYPOPARATHYROIDISM

WHAT CATARACT APPEARANCE WOULD RUBELLA GIVE?

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PEARLY NUCLEAR SCLEROTIC

GOLD STANDARD MANAGEMENT OF CATARACT?

+Brief explanation

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Phacoemulsification

Ultrasonically driven needle (phase tip) to chop the nucleus and then aspirate the lens material.

What technique may be used for very hard cataracts?

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Extracapsular cataract extraction (ECCE)

What is the equation for calculating power of the intraocular lens?

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P = A - 2.5L -0.9K [SRK/T Formula]

P= Lens power (diopters)
A= Constant
L= Axial length of the eye (mm) 
K= Average keratometry (Diopteric measurement of the curvature of the cornea)

What is the normal axial length of the adult eye? | Usual lens power in adults and children

22-25mm 15-20D (Adults) 43-47D (Infants)

What is Biometry?

Process of using biological measurements of the eye to calculate a lens that will offer a set refractive outcome.

Types of IOL used in cataract surgery?

Rigid | Flexible - Acrylic Hydrophobic/hydorphilic or Silicone lens

List the Intraoperative and Postoperative Complications of cataract surgery?

Intraoperative - Posterior lens capsule rupture, Floppy iris syndrome, suprachoriaidal haemorrhage (avoid px with uncontrolled bp/high inr), Trauma (Cornea, Iris, Anterior capsule, Dropped nucleus) Postoperative - Posterior cataract opacification(PCO) Endophthalmitis, Macular oedema (Irving glass syndrome) , Acute uveitis/Chronic post op uveitis, Retinal detachment (High myopic patients)

Define Endophthalmitis?

Inflammation of the vitreous and qaqeuous humour caused by infection.

Main features of Endophthalmitis?

Progressive vitritis (blurred vision, floaters), pain, hypopyon and corneal haze.

Types of Endophthalmitis?

Acute - Within 1st week of surgery [Staph.Epiderimis] Delayed - 6wks onwards [Propionbacterium acnes] Post-trauma - Staphylococcus or Bacillus Fungal - Immunocomprimised patients

Management of Endophthalmitis?

Intravitreal ABx or Pars Plana Vitrectomy

What is the most common complication of cataract surgery? SS, Treatment ?

Posterior capsular opacification Posterior migration of lens epithelial cells S - Gradual Vision loss and glare, Sommering rings, Elschnig pearls (grape-like collection of swollen lens epithelial cells) Tx- Capsulotomy with Laser

Define Lenticonus?

Abnormality in the eye that causes a bulge in the front of the lens (anterior lenticonus) or at the back of the lens (posterior lenticonus)

Conditions associated with Anterior and posterior lenticonus?

Anterior - Alport Syndrome (T4 Collegen mutation disorder) Bilateral Posterior - Lowe syndrome, Congenital cataracts Mainly unilateral

CONGENITAL CATARACTS WHAT TYPE IS MOST COMMON?

BILATERAL 2/3 - Mostly Autosomal dominance inheritance | UNILATERAL 1/3

6 MOST COMMON CAUSES OF CONGENITAL CATARACTS?

1. Galactosaemia [AR] 2. Lowe Syndrome (XLR) 3. Fabry Disease 4. Downs Syndrome 5. TORCH intrauterine infections 6. Mannosidosis [AR]

Which type of congenital cataracts require more urgent treatment?

Unilateral <6wks - Higher risk of amblyopia | Bilateral - 8 to 10wks

Management of congenital cataracts?

Surgery Unilateral possible pharmacological mydriasis of the good eye to avoid amblyopia while delay in cataract surgery to allow stable eye growth

Explain Near accommodation of the lens?

Eye brings near objects into focus by contracting the ciliary muscle, Causes relaxation of the zones making the lens more spherical and increasing its diopter power.

Explain Far accommodation of the lens?

Eye brings far obects into focus by relaxing the ciliary muscle . Increases zonular tension , making the lens flat

What is the term when the lens loses the ability to focus on near objects?

Presbyopia Natural ageing process caused by the lens becoming more stiffer. Making it tougher for the ciliary muscle to change the lens shape.

Cataract Flashcards

(42 cards)