In the first of a series of interviews about eye conditions and treatments, Dr Audrey Looi discusses the types of cataracts and the treatments available for them.
What is a Cataract
A cataract refers to an opacity that develops in the eye’s natural lens due to the aging of the lens tissue. Injuries, past eye conditions, medical conditions and genetic disorders may also cause cataracts to form. This includes diabetes as well as long term usage of steroid medications. Depending on the severity and the area within the eye lens in which the cataracts form, a person’s vision may be greatly affected.
This article sheds light on how cataracts impact vision as well as the different symptoms experienced with different types of cataracts. Additionally, we will also cover the fundamentals of cataract surgery.
How a Cataract affects Vision
The eye’s natural lens focuses light rays that enter our eyes, producing clear and sharp images on the retina. When cataracts form, they block or distort the path of light through it, causing blurred images and often times, glare symptoms.
Types of Cataracts
Three main types of cataracts exist based on their appearance or form:
- Nucleosclerotic cataracts – cataracts that affect the central portion of the eye lens.
Nucleosclerotic cataracts cause the lens to gradually turn a dense yellow or brown, even black over time. These cataracts often cause one’s spectacle power to change over time as the refractive index of the lens changes with increasing yellowing. In the later stages, the passage of light is impeded and cause impaired vision even with spectacles. If left alone till the advanced stage, these cataracts may be more difficult to remove and pose greater surgical risks.
- Cortical cataracts – cataracts that affect the outer portion of the lens.
The opacities in cortical cataracts resemble the spokes of a wheel. If these ‘spokes’ extend to the centre of the lens, they interfere with light passage and cause blurred vision. The area of blurred vision is greatest where these opaque spokes are present.
- Posterior subcapsular cataracts – cataracts that form at the back portion of the lens, just deep to the lens membrane.
The blurred vision caused by posterior subcapsular cataracts is typically worse in bright light.
Not every person who has cataracts requires surgery. If you are diagnosed with cataracts while in the early stages, the eye doctor may be able to correct it by prescribing new glasses. However, if you are experiencing a loss of vision to an extent where your daily activities are compromised, cataract surgery may be required.
Cataract surgery involves the removal of the cloudy natural lens and the insertion of an artificial lens (intraocular lens – IOL) to restore clear vision. This procedure is done in Day Surgery and does not require an overnight stay in any medical facility. The surgery typically takes about 15-20 minutes (30-45 min if laser cataract surgery is performed). However, one can expect to spend a total of two to three hours at the medical centre as time is required for administration of preoperative medication as well as for post-operative recovery from sedation and briefing on post-operative care.
The first of part of the operation requires the cataract surgeon to make corneal incisions to allow access to the lens in your eye. Once the incisions are made, Phacoemulsification, the process which employs high frequency ultrasound to break the cloudy lens into small pieces, can commence. After this, gentle suction is used to remove the lens fragments from your eye.
In the second part of the procedure, the cataract surgeon inserts a clear IOL to replace the cloudy lens that was removed. The IOL is positioned in the natural lens membrane which has been left behind to provide support. This new and transparent lens allows clear images to be focused once more on the retina.
Laser Cataract Surgery
Laser assisted cataract surgery, also known as femtosecond laser cataract surgery, allows the surgeon to use a laser device to perform the preliminary steps in cataract surgery, specifically to make corneal incisions, open the lens membrane and to pre-divide the cataract before phacoemulsification takes place. This reduces the amount of ultrasound energy required for the procedure. Some surgeons favour this technique. Others favour non-laser techniques. There are pros and cons for both. A good discussion with your eye surgeon is important to decide which technique you would prefer.
Cataract Surgery Aftercare
Most patients are able to see improvement as early as the day after the cataract surgery is performed. Depending on whether a mono-focal or multi-focal lens implant was chosen, you may be required to wear glasses post-surgery.
Aftercare includes the use of prescribed medicated eye drops multiple times a day as well as the use of a protective eye shield while sleeping. Additionally, you should avoid performing strenuous activities that may stress your eye and take care to reduce exposure to water or dust in order to prevent contamination.
Introducing Ava Eye Clinic
Ava Eye Clinic is headed by Dr Audrey Looi, who has over 20 years of high-volume clinical experience in managing general as well as subspecialised eye conditions. At our eye specialist clinic, you will find quality advice and treatment for cataract conditions. We are confident of delivering precision, safety and care in all our treatments.