Getting Your Sight Back

Diabetes results in several severe eye complications, cataract being one of them.Dr Anand Palimkar informs us about the several treatments and lenses available for cataract today.

Given the important functions our eyes perform for us, it is a given that we must take the best care possible. They are also among the end-organs most often affected by Diabetes, and cases of cataract are high among people with Diabetes. An operation to remove the cataract is usually the only way to improve your sight.

Pre-empting retinopathy

Patients with both cataract and Diabetes require special attention, especially those who have diabetic retinopathy. Cataract patients with known Diabetes should undergo a thorough eye examination before surgery. If the posterior segment (the back two-thirds of the eye) is normal, then surgery for them would be like any other surgery with special care to prevent infections. But if diabetic retinopathy is detected, then it appears prudent to treat the retinopathy before scheduling elective cataract surgery. This may appear obvious, but several cautions must be considered.

The density of the cataract itself might make it difficult in some cases to properly diagnose or treat retinopathy. In addition, diabetic retinopathy may persist despite appropriate treatment. Therefore, it may not be always feasible to delay cataract surgery until the macular edema has completely resolved.

In patients where fundus evaluation is difficult, a diagnostic procedure known as optical coherence tomography (OCT) is widely employed before cataract surgery. This helps assess the possibility of any co-existing retinal disease that could impair vision even after surgery. OCT may be particularly helpful in cases where the visual loss appears to be out of proportion to the degree of cataract.

In eyes with significant diabetic retinopathy, cataract surgery may lead to progression and worsening of the retinopathy, which may further affect patient's vision. In eyes which have otherwise not been much affected by diabetes, cataract surgery is not likely to worsen the retinopathy. Therefore, cataract surgery at an earlier stage is often beneficial for diabetics because it is associated with fewer complications and better chances of regaining sharp vision after surgery.

Types of surgery

The conditions that spell a need for surgery are the same for diabetics as for non-diabetics. Additionally, surgery is indicated if the lens opacity prevents an adequate examination of the fundus.

Surgery involves removing the cloudy lens and replacing it with an artificial lens. Basically there are two types of surgeries to treat cataract

• Phacoemulsification or Phaco-A small incision is made on the side of the cornea, the clear, dome-shaped surface that covers the front of the eye. A tiny probe is inserted into the eye. This device emits ultrasound waves that softens and breaks up the lens so that it can be removed by suction. Foldable lens is implanted in the eye through this 2 mm incision. This kind of surgery is recommended for diabetics because the incision size is small.
• Extracapsular surgery or small incision cataract surgery– Here doctors make a longer incision on the side of the cornea and removes the cloudy core of the lens in one piece. The rest of the lens is removed by suction. After the natural lens has been removed, it is often replaced by an artificial lens, called an intraocular lens (IOL). An IOL is a clear, plastic lens that requires no care and becomes a permanent part of your eye. Light is focused clearly by the IOL onto the retina, improving your vision.

Types of lenses

• Monofocal lenses –A lens with one focal length, possessing a fixed field of view. PMMA was the first material to be used successfully in intraocular lenses. Advances in technology have brought in the use of acrylic (hydrophilic and hydrophobic) and silicone both of which are soft foldable inert materials
• Multifocal IOLs –This helps in simultaneous viewing of both distance and near vision. Some patients report glare and halos at night time with these lenses.
• Accommodating IOLs – These are the closest to natural lenses. They shift position with the action of eye muscle, to help you see clearly while looking at distant, midrange as well as near objects.
• Toric IOLs – They correct astigmatic vision. This refers to a vision problem in which the objects at all distances appear to be blurred or distorted to some degree, due to the inability to focus an image correctly on the retina.

Weighing the risks

Before choosing the type of surgery and lenses, you need to know the pros and cons of an operation. A cataract operation nowadays is generally very safe, and with a surgeon who is experienced in cataract keyhole surgery, the risk of serious complications is less than one percent. Despite all the care sometimes, however, some people do develop complications. Diabetics are at a greater risk of developing problems like:

• Macular edema (swelling on the retina) fluid accumulating after cataract surgery, causing reduced central and detailed vision.
• Complications from proliferative diabetic retinopathy like bleeding in the vitreous gel.
• The retinopathy itself may progress
• Higher risk of infections.

Make an informed choice

All this is in no way to say that surgery for cataract is a bad idea. You should ideally talk to your eye care professional and come to a mutual decision that is best suited to your unique case. Once you understand the benefits and risks of surgery, you can make an informed choice about how to go about it.

Every eye is unique, and cases that pose a specific challenge can be discussed with the patient and family members. Having said that, most Diabetes patients are likely to achieve very favourable results from cataract surgery.