Only surgical options are available for the definitive treatment of cataracts.
- Maintain eye comfort
- Promote early visual rehabilitation
Visual improvement may be achieved during early cataract development through:
- Change in spectacle lens prescription
- Use of bifocals
- Magnification or other visual aids
- Appropriate illumination
General considerations for surgery:
- Lens removal in cataract patients:
- Usually recommended when vision change is affecting the patient’s activities
- Surgery is usually done one eye at a time
- Cataract surgery is usually done under local anaesthesia. Sometimes only topical drops are required
- Intraocular lens (IOL) implants are inserted at the time of cataract extraction
- If IOL is not implanted then the patient is prescribed ‘strong’ glasses or contact lenses to correct refractive error
Contraindications for Surgery:
Cataract surgery is contraindicated when it will not improve visual function due to the presence of coexisting ocular disease
Surgery should not be performed when the patient is unfit for surgery due to underlying systemic disease or coexisting medical conditions
Coexisting conditions in which cataract extraction with IOL implantation are usually contraindicated include:
- Active proliferative diabetic retinopathy (unless cataract removal is necessary to allow visualization of the retina)
- Rubeosis iridis and/or neovascular glaucoma
There are currently 4 main surgical options for cataract.
1) Intracapsular cataract extraction (ICCE): Rarely done anymore
Method involves extraction of the entire lens, including the lens capsule.
Currently it is indicated in very few cases, such as; for a dislocated lens with Marfan’s syndrome.
2) Extracapsular cataract extraction (ECCE)
This method involves the removal of the lens nucleus through an opening in the anterior capsule with retention of the integrity of the posterior capsule.
ECCE advantages over ICCE surgery:
- A smaller incision ~10-14 mm
- Complications of vitreous adherence to the cornea, iris, and incision are minimized
- A better anatomical placement of the IOL is achieved with an intact posterior capsule
- Intact capsule prevents bacteria and other microorganisms from gaining access
- Safer choice for secondary IOL implantation, filtration surgery, corneal transplantation, and wound repairs due to intact posterior capsule
3) Manual small incision cataract surgery (MSICS)
A form of ECCE which uses a smaller incision (6-8 mm) and a scleral tunnel that is self-sealing. Results in significantly less astigmatic error.
99% of cataracts in North America is done with this technique.
Extraction of the lens nucleus is performed through an opening made in the anterior capsule. First, the lens is fragmented using ultrasound energy and then aspirated.
- Usually requires only topical anesthetic and mild sedation
- Very small incision in the cornea, usually 2-4 mm
- Usually requires one or even no sutures
- Rapid healing
- Rapid visual rehab
- Better control
After the removal of the lens, the patient is referred to as Aphakic (without lens). The lens must be replaced in order to focus light on retina for patient to see clearly.
There are three lens replacement options:
- Aphakic Eyeglasses: Effective but heavy, peripheral vision limited
- Contact Lenses: Provide almost normal vision, but needs to be removed occasionally so eyeglasses are still required
- Intraocular Lens Implants (IOL): A regular approach during cataract surgery, there are certain condition like diabetic retinopathy, uveitis, chronic iritis, neovascular glaucoma, retinal detachment, in which implantation is contraindicated
Toxic Anterior Segment Syndrome (TASS):
A non-infectious inflammation caused by a toxic agent after uneventful surgery, and is a complication of anterior chamber surgery.
- Usually begins less than 24hrs after surgery
- Presents as corneal edema along with pain and reduction in visual acuity
- Managed by topical steroids, but may be hard to distinguish from endophthalmiti
Note: There are many potential complications of cataract surgery, some of which can be intraoperative, early and late postoperative.
It is the newest option where laser therapy is adopted for cataract removal, with fewer complications when compared with the conventional surgeries.
It can be used for wounds, opening of the lens and for the segmentation of cataract; in conjunction with phacoemulsification to remove the lens pieces.