Cataract
Definition
A lens opacity or cloudliness
Pathophysiology
Can develop in one or both eyes
At any age
Over many years or in a matter of months
Types
Most common : Senile - due to aging
Types by location
Nuclear
cortical
Posterior subcapsular
The extent of visual impairment depends on the size, density and location in the lens
More than one type can be present in one eye
Nuclear type associated with myopia - as it progresses periodic changes in prescription eyeglasses needed
Cortical type involves tyhe anterior, posterior, or euatorial cortes of the lens - cataract in the equator or periphery of the cortes does not intefere with the light and hence little effect on vision
Posterior subcapsular cataracts occur in front of the posterior capsule. in younger people - may be associated with prolonged corticosteroid use, inflammation or trauma - Near vision is diminished; sensitive to glare from bright light (sunlight, head lights)
Clinical Manifestations
Painless, blurry vision
A dimness of vision as if glasses need cleaning
Light scattering → reduced contrast sensitivity, sensitivity to glare and reduced visual acuity
Myopic shift, astigmatism, monocular diplopia
Color shift (i.e. the aging lens becomes progressively more absorbent at the glue end of the spectrum)
Reduced light transmission
Assessment and Diagnostic Findings
Decreased visual acuity
Snellen visual acuity test
Ophthalmoscopy
Slit-lamp biomicroscopic examination to assess the degree of cataract
The degree of lens opacity does not always correlate with the patient's functional status
Medical Management
No nonsurgical treatment cures cataract
In the early stages glasses, contact lenses, strong bifocals or magnifying lenses may improve vision
Reduce glare by proper light
Mydriatics - a short term remedy
Surgical Management
Fewer than 15% need surgery
If reduced vision does not interfere with normal activities surgery may not be needed
Surgery performed as OP
Patient is dicharge in 30 minutes
Intra ocular lens implanted - foldable lens with accurate intraocular lens measurements - under topical anesthesia - lidocaine gel - ideal for patients receiving anticoagulants
One eye is operated on first - the other eye if needed operated on after an interval of several weeks or months
Intracapsular Cataract Extraction
An old method not practised now
Done only when there is a need to remove the entire lens, such as with a subluxated cataract.
Extracapsular Surgery
ECCE (Extracapsular cataract extraction)
Posterior capsule of the lens is maintained
A portion of the anterior capsule is removed
lens nucleus and cortes are removed
The posterior capsule and zonular support are left intact
Potential Complications of cataract Surgery
Early Postoperative Complications :
Acute bacterial endophtlamitis - Staphylococcus epidermitus, S.aureus, Pseudomonas and Proteus species
Late Postoperative Complications
Suture related problems
Malposition of the IOL
Chronic endophthalmitis
Opacification of the posterior capsule (visual acuity is diminished - YAG laser is used to create a hole in the posterior capsule. Blurred vision is cleared immediately)
Phacoemulsification
Extracapsular surgical method - ultrasonic liquefication of the lens nucleus and cortex and removal - since the incision is smaller than that in ECCE wound heals more rapidly - early stabilization of refractive error and less astigmatism.
Hardware and software advances in ultrasonic technology - including new phaco needles that are used to cut and aspirate the cataract - permit safe and efficient removal of nearly all cataracts through a clear cornea incision that is as small or smaller than reqquired for available foldable lenses. Ultimately, advances in technology will achieve an injectable IOL.
Contraindications for IOL
Recurrent uveitis
Proliferative diabetic retinopathy
neovascular glaucoma
Rubeosis iridis
Nursing Management
No routine preoperative investigations are needed - according to pt's medical history only necessary investigations may be done
If the patient is on Anticoagulation therapy it may have to be withheld for 5 to 7 days (until prothrombin time of 1.5 is almost reached)
Mydriatics every 10 minutes for four doses at least one hour before surgery and immediately before surgery
Antibiotic, corticosteroid and NSAId drops
Providing Postoperative Care
Give writen instructions regarding how to protect the eye, administer medications, recognize signs of complications
Activities to be avoided to be instructed
Postoperative analgesics - like acetaminophen
Antibiotic anti-inflammatory and corticosteroid eye drops to be applied postoperatively
Promoting Home and Community-Based Care
Prevent accidental rubbing or poking of the eye
Eye patch for 24 hours or eyeglasses
Metal shield worn at night for 4 weeks
Slight morning discharge - clean with damp washcloth
Patient has to report new floaters (i.e. dots) in vision, flashing lights, decrease in vision, pain or increase in redness
Continuing Care
For complete improvement it takes 6 to 12 weeks
After that corrective glasses prescribed
