Overview of Cataracts
Cataract surgery and Laser vision correction are two of the most commonly performed surgeries worldwide. Cataract surgery addresses the opacification of the natural crystalline lens in our eye, which commonly occurs due to aging. Laser vision correction, often represented by LASIK (Laser-assisted in situ keratomileusis), on the other hand, treats imperfect refractive errors such as myopia, astigmatism and hyperopia. As cataracts and refractive errors are very common problems affecting our eyes, their management commonly “cross paths”.
The most common scenario would be someone who had previous LASIK for myopia and astigmatism in young adulthood, who developed cataracts and required surgical treatment later in life.
What are Cataracts?
Cataracts are changes in the lenses in our eyes which usually involves hardening, yellowing, loss of transparency and sometimes, in advanced stages, bulging and total whitening. They typically occur due to natural ageing, but can also be due to injury, metabolic diseases such as diabetes and using medications like steroids.
How does Cataract surgery work?
Cataract surgery removes the abnormal lens content, leaving behind an empty lens sac, called a capsular bag, into which an artificial intraocular lens is implanted. These steps are usually done during the same surgery. The artificial lens implant is generally customisable to the person’s eye power.
Types of cataract surgery
Conventional cataract surgery uses ultrasound energy through a hand-held probe that looks like a pen, which shatters the lens content into tiny pieces. This technique is called phacoemulsification. The probe is introduced via a small cut at the side of the front of the eye measuring just 2-3 mm in length. The lens pieces are then suctioned out of the eye in an intraocular environment protected by fluid flow.
Before the invention of phacoemulsification, cataracts were removed from the eye through much larger cuts in the eye via the technique called ECCE (extracapsular cataract extraction). The larger cuts generally need to be secured with several fine stitches. In some countries, an improved version of ECCE called MSICS (manual small incision cataract surgery) is still performed.
In the past decade or more, a newer cataract surgery technique incorporating a type of laser called the femtosecond laser has been introduced. The femtosecond laser is the same class of laser used in LASIK surgery (to create the LASIK flap or the RELEX SMILE lenticule). This surgery is called FLACS (femtolaser-assisted cataract surgery). It presents an alternative laser-assisted way to perform several steps of the cataract surgery, such as making the initial cuts into the eye, opening the lens sac and pre-chopping the cataract in preparation for the ultrasound probe.
FLACS has potential advantages, such as making the surgical steps more uniform, reducing the overall ultrasound energy required, and making results more predictable. However, as the laser technology is not deemed cost-effective nor essential for all cases, its adoption is sporadic and not consistent.
Current popular options for cataract surgery in Singapore are:
- Conventional phacoemulsification with intraocular lens implant
- FLACS (Femtolaser-assisted cataract surgery, with phacoemulsification) with an intraocular lens implant.
Note that in addition to the 2 options listed above, the options of what intraocular lens is implanted into one’s eye are even more exciting. To date, types of lens implant designs have multiplied many folds since its first invention during WW2. That was after eye doctors accidentally discovered how pieces of perspex lodged in fighter pilots’ eyes from shattered windscreens were safely incorporated and even able to alter the degree of the eye. Nowadays, you don’t have to hope for such accidental fortune as we have the luxury of choosing from the latest lens implants to correct our eye power imperfections during cataract surgeries.
Cataract surgery is almost always performed as day surgery, either in a hospital or day surgery centre, meaning that it does not usually require overnight admission into the hospital. In many cases, it can be performed under eye drop anaesthesia with gentle sedation, and actual surgery may be as short as around 15 minutes in experienced hands.
Are There Risks to Cataract Surgery?
The success rate of cataract surgery in Singapore is very high. Most centres quote close to 100% (98-99%). However, special precautions are still necessary and always taken to prevent postoperative infections of the eye, which is fortunately of a low rate here (1 in 10,000). Care is also taken for possible risks like inflammation of the eye, swelling of the front or back of the eye, eye pressure fluctuations, bleeding and rarer problems like retina detachments. Most of these are mild and readily manageable during the post-operative reviews. In many cases, patients can see very well within the first few days after surgery but will require careful eye drop treatment for around 4 weeks.
Can I Develop Cataracts After LASIK?
Of course. Doing LASIK merely changes the curvature and thickness of the cornea, the front structure of the eye. The lens inside the eye will still undergo aging changes like any other eye.
There is no significant difference between cataract surgery for LASIK patients and non-LASIK patients, except that the cornea curvatures of LASIK patients are usually flatter (for previously short-sighted eyes). You need to inform the cataract surgeon regarding your previous LASIK so that it can be taken into consideration when calculating the power of the lens implant of choice.
When should I consider cataract surgery after LASIK?
In general, the age group of cataract patients range from mid-40 to 90+ years old. In Singapore, cataract surgery is routinely done in those above 60 years old. However, younger patients develop early-onset cataracts too, for example, if there are associated conditions like high myopia, eye inflammation or injury, diabetes and previous medications like steroids. People with short eyeball length who are more at risk of developing angle closure glaucoma are also recommended to consider early cataract surgery.
In comparison, our LASIK patients range from 18-55 years old, with treatment available for myopia, hyperopia and astigmatism (as well as presbyopia for those around 40 years old and beyond, using the Zeiss Presbyond treatment).
So, for those whose age straddles both LASIK and cataract age groups, speak to us to find out what would be a suitable option for you.
How will I be evaluated for cataract surgery if I’ve had LASIK?
The standard preoperative evaluation tests for cataract surgery apply after previous LASIK, such as a full eye test with dilated fundoscopy to check for other concurrent eye problems and a good quality biometry, preferably one using infra-red technology (a scan to measure the eye dimensions to select an accurate lens implant power).
You MUST inform the surgeon that you had LASIK done before, and if possible, what your eye power was before LASIK. The calculation for the lens implant power, performed by the eye surgeon, needs to take into account the previous LASIK treatment. Done properly, based on a few modern calculation formulae and methods, it can be as accurate as other cataract surgeries.
Nevertheless, there is still a tiny possibility (less than 0.5%) of unpredictable eye power after any cataract surgery. Should significant inaccuracy happen, patients can consider remedial treatment such as with a LASIK enhancement or an exchange of the lens implant, although this is only advisable when wearing glasses is not accepted by the patient.
What are the surgical techniques used for post-LASIK cataract surgery?
The surgical techniques for cataract surgery after previous LASIK are the same as for those who have not had LASIK.
Although FLACS offers marginally higher predictability for eye power outcome, in principle, conventional or FLACS is no different with or without previous LASIK.
Are there any risks associated with post-LASIK cataract surgery?
There is no significant increase in the risks and complications of cataract surgery after LASIK. All cataract surgery patients are advised to follow post-operative care instructions, such as strict eye and hand hygiene, and use the necessary eye drops.
Some common postoperative side effects, like dry eyes and seeing slight glare and halos, usually subside after a few weeks to months. These problems are more commonly associated with multifocal lens implants, which some post-LASIK patients may want to avoid.
Other lens implant options available for post-LASIK patients include the enhanced monofocal or the new pinhole lens implants (Acufocus IC-8). These may contribute to spectacle freedom.
Generally, three post-operative eye checks are recommended: on day 1, day 5 and 1 month after the operation.
Other than keeping the eyes clean and sleeping with a protective shield over the eye for a week, postoperative antibiotics and steroid eye drops are required for a month. Swimming should be strictly avoided for a month. Patients can resume exercises several days after the cataract surgery.
Eye power checks are usually formally performed a month after surgery, as the lens implant will need some time to stabilise in the lens capsule. Hence, patients are advised to delay making any required prescription glasses in that duration.
Cataract surgery after LASIK is a safe and effective procedure and represents a second chance to improve our eyesight after LASIK. With meticulous planning and calculation, taking into account previous LASIK measurements, the results of cataract surgery can be as great as LASIK.
Intraocular lens implant designs are ever-evolving, and so too is the method of calculating the power of the lens implant required. We have plenty to look forward to in this field, with ever-improving optical and refractive results for cataract surgery post-LASIK!
LSC Eye Clinic offers an emergency service for patients with urgent eye problems requiring immediate medical attention. Call to obtain an appointment today to safeguard your sight!
About the Author
Dr Daphne Han is a Senior Consultant Ophthalmologist at LSC Eye Clinic in Paragon. She has been in practice for over 20 years. She is highly skilled in an extensive range of laser vision correction surgeries such as ZEISS SMILE®, LASIK, LASIK Xtra, Advanced Surface Ablation and Implantable Contact Lens (ICL).
Dr Han was previously a Consultant Ophthalmologist at the Singapore National Eye Centre (SNEC) Cataract and Comprehensive Ophthalmology and Laser Vision Centre and Adjunct Assistant Professor at Duke-NUS. She was a faculty trainer in cataract surgery and LASIK to fellow doctors. She authored articles in scientific journals and textbooks and is an invited speaker at meetings, and is an examiner and reviewer for professional journals. She had also formerly held appointments as Lead Ophthalmologist at SMG Vision Center, Gleneagles and Singapore Medical Specialist Centre.
Having seen her fair share of patients who sought help too late, Dr Han strongly believes that good eyesight is one of life’s most precious treasures. She makes all efforts to help patients preserve and achieve the best potential in their eyesight, guided by evidence-based medicine as well as holistic and informed choice.
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