Cataracts are a clouding of the naturally transparent lens of the eye. It occurs due to a build up of proteins in the natural lens. This reduces the amount of light going into the eye and causes decreased vision.
Symptoms of cataracts include:
- Blurring of vision
- Glare and halos around bright lights
- Decreased night vision
- Decreased contrast and colour perception
- Worsening myopia (frequent changes in glasses power)
What is the difference between standard cataract surgery (phacoemulsification) and bladeless cataract surgery (femto-second laser assisted cataract surgery – FLACS)?
In standard cataract surgery (phacoemulsification), sharp surgical blades are used to create small wounds (<3mm) to allow surgical access for the ultrasound probe used to break up and remove the cataract. With bladeless cataract surgery (femto-second laser assisted cataract surgery – FLACS), a femto-second laser is used in place of the blades to not only create the corneal wounds, it is also to create an opening in the lens capsule and break up the cataract. The subsequent removal of the cataract still relies on the ultrasound probe.
Benefits of cataract surgery include:
- Restoring vision
- Quick recovery with minimal downtime
- Minimal pain and discomfort during the recovery period
- Minimal disruption to work schedule
- Ability to correct any refractive error at the same sitting
- Ability to address presbyopia (lao hua yen) at the same sitting
Benefits of FLACS include:
- 100% Bladeless surgery
- Precision in wound creation
- Precision in capsulorrhexis creation
- Minimize ultrasound energy needed to remove the cataract
- Less damage to the corneal endothelial cells during surgery
A thorough assessment should be done before proceeding with cataract surgery to ensure there are no other eye pathology that would account for the symptoms of blurred vision. In general, a suitable candidate for cataract surgery includes patients who:
- Visually significant cataract
- No other eye pathology that needs to be addressed first
- Keen to be free of glasses or contact lenses
Cataract surgery is quick day surgery that does not require hospitalization, taking about 10-15 minutes for each eye. After the cataract is removed, an artificial lens (Intraocular lens) is placed in the lens bag to correct the refractive error present. Recovery is generally comfortable with minimal discomfort. Antibiotic and steroid eye drops are given after cataract surgery for about a month to prevent infection and minimise inflammation. Many patients are able to return back to normal activities in 1-2 weeks.
Cataract surgery is considered one of the safest surgical procedures around. As with any surgery, there are potential risks which should be understood.
Risks of cataract surgery include:
- Bleeding, infection, inflammation
- Zonulysis, Posterior capsular rupture (PCR <1%), dropped nucleus
- Retinal detachment, corneal decompensation
Recovery from cataract surgery is quick with minimal downtime with many returning to work in 2-3 weeks. It is important not to rub your eyes during this early recovery period. A hospitalisation medical certificate is issued cover any absence from work after cataract surgery.
During each follow up consultation after cataract surgery, the recovery process is assessed and advise given on when returning to exercising is suitable. Most patients are able to return to running, jogging and gyming within 1-2 weeks. Swimming should be avoided during the early recovery period.
Cataract surgery itself is painless due to the numbing eye drops given before surgery begins. After cataract surgery, there may be some discomfort immediately after the procedure, this largely resolves by the following day.
Significant improvement of vision is expected immediately after cataract surgery compared to the previous unaided vision without glasses or contact lenses. There may be some blurriness which will settle down over a few days. About 98% will no longer need glasses or contact lenses to meet legal requirements for driving if there are no other eye pathology that compromises vision.
During cataract surgery, the anesthetist may give you a mild sedation to make you feel drowsy. You may fall into a light sleep during the surgery itself.
In modern day cataract surgery, phacoemulsification can be performed via a wound that is less than 3mm in size. This wound is self sealing and does not require any stitches. This is vastly different from the older methods of cataract surgery which required a large wound more than 10mm and multiple stitches.
After cataract surgery, avoid getting any water into the eye, avoid swimming in the first month and avoid vigorous exercise in the first 1-2 weeks. it is also important to avoid eye rubbing and to keep the prescribed eye drops going as planned. Goggles are given and should be used at night to prevent eye rubbing during sleeping hours.
With cataract surgery, the implanted lens (Intraocular lens) is able to treat hyperopia (long-sightedness), myopia (short-sightedness) and astigmatism.
Cataract surgery can treat presbyopia in several ways. This can be in the form of monovision where one eye is corrected for distance vision and the other eye corrected for near vision using monofocal intraocular lenses. Patients may simulate this with a trial of contact lenses before undergoing cataract surgery.
Another option would be to use multifocal intraocular lenses which has by virtue of the lens design, the ability to aid vision for distance, intermediate and near vision.
Cataract surgery is expected to last a lifetime. Once cataract surgery is done, the cataract does not grow back. In intraocular lens that is placed in the eye is made of a very inert and stable material with negligible changes over time.
After some time (months to years), some patients may develop blurred vision after cataract surgery. This is due to a growing of some of the lens cells which lines the back of the lens bag and blocks light. This is not a cataract and repeat cataract surgery is not needed. This condition also known as a posterior capsular opacification (PCO) can be easily treated with a YAG laser in a clinic setting.
Cataract surgery is usually done one eye at a time with the second eye undergoing cataract surgery a few days to weeks later. Some patients choose to have both eyes done at the same sitting to minimise downtime and having to repeat the recovery process. This can be arranged if it is your preference.
After cataract surgery, an intraocular lens is implanted into the eye to correct any refractive errors. There are different options to choose from.
Monofocal lenses focuses vision at a fixed distance. This can be targeted for distance vision (beyond 100cm), intermediate vision (80cm, computer work) or near vision (40cm, near work). When looking at objects at the specific distance, the object is in focus but objects at other distances are out of focus.
Multifocal lenses allows for focused vision at distance, intermediate and near vision.
Extended depth of vision (EDOF) lenses are designed to increase the range of focus compared with monofocal lenses, allowing for distance and intermediate focused vision.
Not all intraocular lenses are designed with the ability to astigmatism. Those designed to correct astigmatism are called toric lenses. These can be monofocal or multifocal by design.
Premium intraocular lenses have certain characteristics including:
- Apheric: The non-uniform curved design of these lenses enables them to correct spherical aberrations of the eye and hence increase image quality
- Toric: The lenses are able to correct astigmatism when aligned correctly in the right orientation
- Multifocal: These lenses allow for clear vision at all distances (Far, intermediate and near)
- Extended Depth of Focus (EDoF): These lenses provides a larger range of clear vision compared with monofocal lenses
The main advantage of multifocal intraocular lenses is the ability to focus and see clearly at all distances. The lens is not only able to address refractive errors like hyperopia (long-signtedness), myopia (short-sightedness) and astigmatism, it is also able to address the concerns of presbyopia (lao hua yen). This may eliminate the need for glasses for distance or near work.
Risks of multifocal intraocular lenses include:
- Glare and halos
- Decreased contrast sensitivity
- Decreased night vision
- Need for brighter light when reading
A thorough history, eye examination and specialised tests are done to assess suitability for multifocal intraocular lenses.
Some factors which make for a poor candidate for multifocal lenses include:
- High expectations of perfect vision for distance, intermediate and near vision
- Night driving
- Prolonged reading and near work
- Other eye pathologies: e.g. Irregular corneas, glaucoma, weak zonules, macular degeneration, retinal detachment
Monofocal lenses provide sharp and clear vision at a fixed distance. It avoids the risks of multifocal intraocular lenses such as glare, halos, decreased contrast sensitivity, decreased night vision.
Monofocal lenses are not able to provide a range of focused vision. If both the eyes are targeted for clear distance vision, glasses would be needed to have focused vision for intermediate and near work.
EDoF lenses provide sharp and clear vision over a range of vision (distance and intermediate vision). It avoids the risks of multifocal intraocular lenses such as glare, halos, decreased contrast sensitivity, decreased night vision.
EDoF lenses do not provide as good a vision for near tasks compared with multifocal lenses. Patients may still need reading glasses for prolonged near work.
There is no single best intraocular lens for everybody. A thorough assessment should be made to determine which type of intraocular lens and their respective optics would best help you achieve your vision goals.
During an assessment, a detailed history will be taken from you and specialised test to gather data on suitability will be done. This includes checking your visual acuity, refraction, corneal topography, eye anterior segment examination, dilated fundus examination and other specialised tests directed by examination findings. Based on the assessment results, Dr Val Phua will then have a detailed discussion on the various options for cataract surgery and recommend a suitable treatment plan including the choice of intraocular lens to meet your vision goals.