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
Complications of cataract surgery
Intra-op
- Posterior capsule rupture
Early
- Endophthalmitis: bacterial or fungal infection inside the eye involving the vitreous and/or aqueous humors (devastating)
- Corneal edema
- IOL malposition/ Dislocation
- Cystoid Macular edema (most common) and retinal thickening
- Toxic anterior segment syndrome (Inflammation of anterior segment of eye within 24h of surgery; A/w non infectious contaminants of equipment)
- Vitreous communication due to PCR
Late:
- Retinal detachment
- Posterior capsule opacification (Treat with YAG Laser Capsulotomy)
Causes of poor vision after cataract surgery
Age-related Macular Edema
DM with Macular Edema
Cystoid Macular Edema
Glaucoma
Optic Nerve Disorders
Matured cataract
White opacification seen in the anterior chamber
Main complication of conservative management of cataract
Blindness
Visual prognosis after an uncomplicated cataract surgery
- Expect some blurriness for a few days after cataract removal
- Improved vision within the first several weeks
- Nine out of 10 people see better after cataract removal
- You still may need to wear glasses or contacts after cataract surgery
Steps/Procedure of phacoemulsification
- Fast for 6h before surgery, anesthesia + IV sedation
- Creation of wound in pars plana <3mm
- Continuous circumlinear capsulorhexis (CCC) incision
- Hydrodissection to separate lens from capsule
- Use ultrasound energy to fragmentize the opacifications and a vacuum to remove them
- Inject folded IOL through wound
- Inject balanced salt solution (no need to suture the wound, the pressure closes up the wound)
Advantages of phacoemulsification
Smaller incision
No sutures required
Fast visual recovery
Causes of young cataract
Congenital
Hereditary
High myopia,
Trauma
Metabolic disease
- Wilsons
- Galactosemia
- Homocysteinemia
Down syndrome, turner syndrome
TORCHES infection
What is posterior capsule opacification?
An “after cataract” that forms after a cataract surgery:
Residual lens epithelial cells are left behind after surgery and migrate along the back surface of the implant and opacify the posterior capsular bag
Treatment for posterior capsule opacification
YAG Laser Capsulotomy
Meaning of phakic, psuedophakic, aphakic
Phakic = normal lens
Pseudophakic = implanted lens
Aphakic = no lens
