CVL: Cataract Flashcards
What is cataract?
Opacity of the crystalline lens due to proliferation of cells within the lens, causing the lens to thicken
Causes of cataract
- Old age
- DM
- Long term drug use (steroid)
- Long term UV exposure
- Traumatic
- Congenital
Types of cataracts
- Cortical cataract
- Subcapsular cataract (posterior > anterior)
- Nuclear sclerotic cataract
- Mature cataract
Symptoms of cataract
Gradual onset
Progressive over time
Painless
Blurring of vision
Monocular diplopia
Increase myopia
Increase glare (especially posterior capsular and cortical cataracts)
- halos around lights
- difficulties with night driving
2nd sight phenomenon
What eye examination to do and what to expect?
Torch Light Examination:
- Yellowing of lens
- White pupil (Leukocoria)
- Dilated pupil
Direct Ophthalmoscopy:
- Diminished/Loss of red reflex
Slit Lamp Examination:
- Identify location/extent/ subtypes of cataract
Posterior subcapsular cataract
*located back of lens
Worse in bright light
A/w long term use of steroids, DM
Most disabling
Opacity looks like breadcrumbs or sand sprinkled onto the back of the lens
Cortical cataract
Worse in dim light (Dilation of pupil causes more light to pass through radial spokes; more noticeable)
Radial or spoke-like opacification
“bluish”
Nuclear sclerosis
Yellow to brown discolouration of central part of lens
Unequal vision
2nd sight phenomenon
“Greenish yellowish”
What phenomenon can be observed in nuclear sclerosis?
2nd sight phenomenon
- increased myopia due to increased refractive power of denser nucleus
- may be able to read without reading glasses
Complications of cataract
- Uveitis
- 2° to leakage of lens protein - Glaucoma: Lens-induced glaucoma
- Phacolytic (Leakage of lens protein)
- Phacomorphic (Swollen intumescent lens -> push iris forward -> block drainage angle -> raise IOP)
- Lens Subluxation - Blindness
Indications of cataract surgery
- Symptoms from cataract interfere with patient’s ability to perform daily function
- Poor vision
- Cataract induced complications
- Patient requires treatment of blinding retinal disease
Pre-op assessment for cataract
Ocular
- Best corrected visual acuity
- Slit lamp examination
- Tonometry: Intraocular pressure
- Fundoscopy
- Biometry - Used to select right intraocular lens (IOL) by measuring the:
Length of eyeball
Corneal curvature
Calculates IOL power
General
- ECG, BP, Urine dipstick ± Referrals to PMHx
Types of intraocular lens (IOL)
- Monofocal: for looking at far distance
- Multifocal: able to see both near and far, but general quality of images may not be as clear; can also cause halos around bright lights at night
Toric means + astigmatism
Toric monofocal
Toric multifocal
What anaesthesia can be used for cataract surgery?
Peribulbar/retrobulbar injection or
Topical anaesthetic eyedrops
Types of cataract surgery
- Phacoemulsification + Intra-ocular lens implantation
- Extra-Capsular Cataract Extraction
- Intra-Capsular Cataract Extraction
