How to choose the right lens for cataract surgery

 

Cataract surgery is one of the very commonly done eye surgeries.  Crores of patients world wide undergo cataract surgery to regain their sight

In cataract surgery, an artificial lens is implanted. An Intraocular lens (IOL) helps the patient to restore lost vision as well as correct the refractive error they had prior to surgery

Different lens types are available to match patients lifestyle and eye requirements

Ophthalmologist will help you prior to surgery in choosing the best suited lens for your eyes. Your lifestyle requirements, budget and insurance coverage is also considered while offering you the best.

Lets understand the various artificial lenses available for your eyes

The options we have are

• Monofocal IOLs are made to focus at a particular fixed distance. Most patients who opt these monofocals, get it fixed for distance vision. These patients usually require reading glasses.

• Multifocal IOLs  are designed in such a way that they help you with distance as well as near work such as reading. The newer trifocals help with intermediate distance which is our screen viewing distance (mobile, laptop usage)

• Extended depth-of-focus i.e. EDOF lens: they are designed for distance and intermediate work. But the patients who opt them require some reading glasses

• Toric lenses designed to correct astigmatism. They can be monofocal, multifocal or EDOF

Some of the cost, insurance and lifestyle factors which are considered before planning the surgery are as follows...

What can I afford?

Most of the insurance companies and insurance policies usually cover monofocal intraocular lenses. Hence when someone opts for premium lenses such as multifocals, toric or EDOF, out of pocket expenses are incurred. But many corporate policies and policies which have high coverage do cover premium lenses. Sentra clinic and hospital's insurance team will help you with all the insurance related process.

Do you spend a lot of time reading, working on screen etc?

If you like doing a lot of near work you can considered multifocal lens. Also you can set your monofocals in such a way that you can do near work without glasses and for distance you will require glasses. Another option is one eye you can set for distance and other for near work with monofocal lens. This is called mono vision. But this may not suit everyone. Also with Multifocals, some patients do require glasses for some activities.

Do you drive at night?

Multifocal lens can give rise to glare and halos which are mostly experienced with bright lights. This can be uncomfortable to some while driving at night. Hence discuss this with your ophthalmologist before opting for multifocal lens.

Do You Have Astigmatism or cylindrical number in spectacles?

Astigmatism can be corrected by Toric lenses which helps in greater clarity of vision post surgery. Your ophthalmologist will discuss the need for toric lenses if they find it suitable for you

Are you suffering from any other eye disease?

Multifocal and EDOF lenses are usually not ideal for patients with pre existing diseases such as diabetic retinopathy (diabetic eye disease), glaucoma, macular degeneration etc. They allow less light to pass, hence may increase difficulty for patients. Monovision as described above can be considered to reduce dependence on glasses.

I hope above information helps you to converse better with your ophthalmologist. The above mentioned information is just a point of view. Your ophthalmologist will be the best suited person to guide you with the lens choice

Lets understand what is cataract? what are different types of intraocular lenses? how the surgery is done?

 

What is a Cataract?

Inside your eye is a natural lens that helps focus light. The natural lens focuses images onto the back of our eye (called the retina) so you can see clearly. This is just like a camera lens focuses images onto film for a clear picture . As people age, the natural lens can become less clear, even cloudy. This cloudiness is called a cataract. Just as a dirty camera lens can spoil a picture, a cataract can prevent light from focusing clearly inside the eye.

Typical signs of cataracts are blurred vision and sensitivity to light. For example, you may have trouble reading, or driving at night or at dusk. Colors may seem less vivid. It may be difficult to thread a needle, shave, or put on make-up. A cataract can be removed only by surgery. You should consider surgery when cataracts cause enough loss of vision to interfere with your daily activities.

What is Astigmatism?

Astigmatism is caused by an irregularly shaped cornea. This results in blurred distance and/or near vision. A normal eye has a round cornea, shaped like a baseball. Light rays entering the eye focus at a single point on the retina, forming a clear image. An eye with astigmatism has an oblong-shaped cornea, shaped like an American football. As a result, the light rays do not focus on a single point on the retina. This causes blurred or distorted vision. Ask your eye doctor if you have corneal astigmatism.

What is an Intraocular Lens (IOL)?

The most common treatment for cataract today is to remove the clouded natural lens. It is then replaced with an artificial lens. This artificial lens is called an intraocular lens (IOL). 

What to Expect before Cataract Surgery

You will be evaluated before surgery. This includes checking for any eye diseases. It also includes measuring your eye to choose the correct lens power. If you wear contact lenses, your eye doctor may ask you to stop wearing them before being tested. Tell your eye doctor if you have any health conditions that may affect your surgery or vision.

Examples include high blood pressure, diabetes, and heart disease. Give your eye doctor a current list of your medications. Plan to have someone else drive you home after surgery

What to Expect during Cataract Surgery

Cataract surgery is usually done as an outpatient procedure. You will be given anesthesia in the form of eye drops to numb your eye. Typically, you will be fully awake during the surgery. You will be comfortable and should feel little or no discomfort. Your eye doctor will use a microscope to have a magnified view of your eye. Your natural lens sits in a bag-like structure called the lens capsule. The lens capsule is located just behind the colored part of your eye (iris). A small incision is made in the outer surface of the eye. The eye doctor inserts a tiny probe through this opening to break up the cataract. Your eye doctor then uses a device like a small vacuum to remove the cataract pieces from your eye. Now there will be room for the IOL to be placed in your eye, to replace your natural lens that your eye doctor has just removed. Your doctor will insert the IOL through the same tiny incision. When the surgery is complete, your eye doctor may place a protective patch or shield over your eye.

Right after surgery, you should stay in the recovery area for a short time. Many patients may begin to see better within 1 to 2 days. Some are stable at 10 to 14 days. Some may take 4 to 6 weeks to recover from surgery. Improvements in vision are different for each person. Call your eye doctor right away if you experience any itching, pain, flashing lights, “floaters,” redness, severe headache, nausea/vomiting, light sensitivity, or watery eyes after surgery.

Different types of lens

Monofocal IOLs

Monofocal IOLs restore distance vision. This means that you should see well when you go to a ball game or read distant signs. You will probably need glasses for near vision tasks, such as reading a book, writing, or doing crafts. You may also need glasses for intermediate vision activities such as working on a computer, putting on make-up, or shaving.

Enchanced Monofocal

Primarily restore distance vision. This means that you should see well when you go to a ball game or read distant signs. You will probably need glasses for near vision tasks, such as reading a book, writing, or doing crafts. You may also need glasses for intermediate vision activities such as working on a computer, putting on make-up, or shaving

Multifocal IOLs

All IOLs are designed for distance vision. Multifocal IOLs are also designed to improve near vision compared to a monofocal lens. This means that you should see well whether you go to a cricket match or read a book. Overall, you may wear glasses less often for daily tasks.

Toric IOLs

Toric IOLs restore clear distance vision for patients with astigmatism. As mentioned above, astigmatism is blurred or distorted vision caused by an irregularly shaped cornea. If you have astigmatism, a toric IOL may be the right choice for you.

For better understanding watch the following video

Glaucoma : the silent thief of vision

 

Glaucoma is a disease that causes loss of sight by damaging a part of the eye called the optic nerve. This nerve carries information from eyes to brain.

Glaucoma is an eye disease which causes loss of sight by damaging the optic nerve. This nerve carries information from your eyes to your brain.

When glaucoma damages your optic nerve, one first loses patches of vision, usually side vision . Over a period of time, glaucoma may also damage central vision. You may not notice a loss of vision until you

have lost a great deal of your sight. When checking for glaucoma, eye specialist usually look for damage to the optic nerve and any loss of vision. They will also check your eye pressure. Glaucoma is called the ‘silent killer of vision’ because people usually do not notice any signs of the disease until too late. Once lost, vision cant be recovered

Who is at Risk for Glaucoma?

These risk factors may increase your chance of having glaucoma:

 Age: The older you are, the greater your risk

 Race: Certain races have higher risk for glaucoma

 Family history : If your first degree relative has glaucoma, you have increased risk

 Systemic history: Diabetes mellitus, previous eye injuries, eye surgery or long-term steroid use anywhere in the body can increase your risk of glaucoma

Investigations:

 Tonometry: the pressure of the eye is measured 

Pachymetry: Thickness of the cornea (the front window of the eye) may affect the pressure reading and the risk of glaucoma progression, pachymetry is The medical terminology for measurement of central corneal thickness.

 Ophthalmoscopy: To examine the Optic nerve

 Gonioscopy: To examine the area in the front of the eye known as the drainage angle.

 Perimetry: Evaluates your visual field.

 Photography: This is a documentary proof of the existing appearance of your nerve in color and black and white. It can be used as a visual record of the nerve appearance over a period of time.

All the above tests will be done at the time of diagnosis and a systematic document would be made that would help the doctor treat you in the best possible way. Some of the above tests need periodic repetition that has a specific scientific logic. Please ask your doctor and understand the details and the logic behind such a routine. This will greatly enhance the way you understand your disease.

 Treatments: Glaucoma can usually be treated and controlled using medicine(s), laser surgery, glaucoma surgery or a combination of these treatments. Medicines (eye drops) are typically the first step in treatment, but laser surgery may be just as effective as a first choice. Your treatment is up to you and your doctor

 Treating Glaucoma with Medicines: Doctors prescribe many types of medication to treat glaucoma. These drugs lower the pressure inside the eye. Often, people with glaucoma have to take these medicines for life to control the pressure and limit vision loss. Remember, you and your doctor must work together to determine the best medicines for you.

Treating Glaucoma with Laser Surgery

Some people may need eye surgery to control their glaucoma. Lasers are very useful for treating glaucoma because they avoid cutting and have a lower chance of complications (compared to glaucoma surgery).

There are three common laser procedures:

 Laser trabeculoplasty

 Peripheral iridotomy

 Laser cyclophotocoagulation.

Treating Glaucoma with Glaucoma Surgery

 Filtering surgery

 Drainage implant surgery