Cataract

• Symptoms: Blurry or foggy vision, light sensitivity, double vision, deplorable night vision, changes in colour perception, a brighter light required for reading, change in spectacle power, fading of colours
• Causes: Ageing, genetic disorders, injury to the tissue that makes up your lens, steroids used to treat lupus and arthritis, exposure of the upper body to radiation treatment, direct exposure to the sun without sunglasses 
• Risk Factors: Old age, eye injuries in the past, diabetes, exposure to X-rays, obesity, smoking, family history of the disease, heavy alcohol dosage, high blood pressure
• Severity: Mild to moderate 
• Which doctor to consult: Ophthalmologist

Overview:

In essence, a cataract is an ailment of the eye that causes the lenses to fog, causing significant vision loss. The condition typically develops over time and needs to be surgically removed to restore vision. A cataract occurs most commonly in older people who might not realize it until the fogging starts hindering vision.

Let's break down how the eye works to understand the condition better. Light passes through the lens, which is situated behind the iris. The light that passes through the lens reaches the retina, which converts the light into signals and passes it to the brain.

If a person develops a cataract, the protein formation on the lens turns it opaque and does not allow a clear image to reach the retina. As a result, incomplete signals are sent to the brain, hindering vision. The eye loses its ability to focus on the light, causing vision loss. The amount of vision loss depends on the size and location of the cataract.

Since cataracts develop over a long period, an individual might have one at the age of 40 but might not realize it until they reach 60. So, an early diagnosis is generally not possible. Eyeglasses and exposure to intense light might help diminish the damage if it is detected early on.

But if the cataract begins to interfere with a person's day-to-day activities, surgery is required to get rid of it. The surgery is relatively effective, safe and does not damage vision further.

When to Consult a Doctor?

Having regular eye checkups is the only way to get ahead of a cataract. Only an ophthalmologist can help detect the presence of cataracts. As an individual gets older, eye examinations become even more critical. Some symptoms of a cataract are as follows:

• Need for more light to read or see things 
• Glares or halos around lights
• Colours start appearing more faded

Further, a patient needs to be more vigilant if he/she identifies one or more of the risk factors mentioned below:

• Is aged 55 and above
• Family members have had cataracts earlier
• Diabetic 
• Spent a lot of time being exposed to direct sunlight without eye protection 
• Have had an eye injury in the past.
• Consuming steroids 
• Have experienced eye disease in the past

Diagnosis

An ophthalmologist will perform some basic diagnostic tests to look for signs of cataracts. This will start with a basic physical examination of the eye.

The doctor will dilate the pupil by administering special eye drops, causing the pupil to widen. Once the pupil opens up, the doctor will try to gauge the eye's overall health by performing preliminary tests. Once the doctor detects the presence of a cataract, he/she will prescribe several lab tests to confirm the suspicion, such as:

• Visual Acuity Test: This test is employed to gauge eye health and the ability to see objects at certain distances. Doctors will ask the patient to read things off a board, where the sizes of the letter will get smaller as they keep going. This measures the accuracy with which the eyes can read from a certain distance. This test can be administered separately to each eye or together.However, the results of this test are calculated in the form of a ratio. 20:20 is referred to as the standard limit. This means that a person can see objects 20 feet away as clearly as someone with perfect vision would be able to see.If the test results turn 20/40, the person can see an object 20 feet away with the same clarity that the average person can see 40 feet away.
• Contrast Sensitivity: This test determines the ability of the eyes to separate an object from its immediate background. If the eyes cannot separate an object from its immediate background in low contrast sensitivity, it is a telltale sign of cataract.
• Slit-Lamp Examination: A slit-lamp examination will allow doctors to study the structure of the eye's front surface. The doctors will use a microscope called a slit lamp, which illuminates the cornea, lens, and iris, with the help of an intense light beam. 
• This apparatus will help doctors study the minute internal structures within the eye. As a result, they can detect any issues and abnormalities in the eyes easily.
• Applanation Tonometry: Applanation tonometry is a test used to determine the fluid pressure in the eyes. This test uses a slit-lamp microscope equipped with a forehead and chin support. At the tip of the apparatus, there is a tiny cone with a flat end that touches the cornea. This helps the doctor figure out how much pressure is required to flatten it temporarily.

Treatment

Surgical Treatment: Surgery is the only way to get rid of a cataract. The surgery involves removing the clouded lens and putting an artificial one in its place. This lens is known as an intraocular lens and will stay in the eye permanently.

In rare cases, people might have other eye conditions that might not accommodate using the intraocular lens. In this case, the cataract is removed, and vision is corrected with the help of contact lenses or eyeglasses. Cataract surgeries are generally of two types:

• Phacoemulsification Cataract Surgery: This is a more common method of surgery for cataract patients. The doctor will cut a small opening in the eye to get to the clouded lens. They will then use a high-frequency laser to break the cloudy lens into minute pieces. This laser is made out of ultrasound waves. The remnant fragments of the clouded lens are then suctioned off, and a new plastic lens is placed.
• Extracapsular Cataract Surgery: This is the route the doctor will take if phacoemulsification surgery is not a good option for the patient. For instance, if the cataract is in its advanced stages, it might be challenging to break it apart.

In this case, the doctor will make a larger opening in the eye and remove it in one piece. The intraocular lens is then put in its place.

The surgical method to remove a cataract is relatively safe. However, there is a possibility that the patient might experience some irritation in the form of the following symptoms:

• Watery eyes 
• Blurry vision 
• Sensitivity to light 
• Discomfort 
• Itching

Risks & Complications if Left Untreated

The most significant complication of untreated cataracts is permanent blindness. This is because the proteins responsible for causing the cataract will start clumping together, damaging the patient's eye permanently.

Here are some of the consequences of a cataract being left untreated:

• Cataracts can considerably heighten the risk of glaucoma.
• Cataracts can enter a "hyper-mature" state, becoming too dense to be removed surgically. 
• The patient's vision will be so impaired that they might become prone to accidental injuries. 
• Untreated cataracts can lead to permanent blindness.
• Additional information

Types of cataracts

The various types of cataracts commonly found include:

• Nuclear Cataract: This is the type of cataract that affects the centre of the lens. The onset of this cataract is announced by near-sightedness or a temporary improvement of overall reading vision. However, the lens will start turning yellow and cloud vision as time passes. 
• If left untreated, the lens might even turn brown, which may cause trouble in telling colours apart.
• Cortical Cataract: This type of cataract affects the edges of the lens. It shows up in wedge-shaped, whitish opacities, which will form streaks on the edge of the lens. If left untreated, these wedges will make their way to the centre of the lens, making it difficult for light to pass through. As a result, the patient will start losing vision.
• Posterior Subcapsular Cataract: This cataract affects the backside of the lens and starts as a minor opaque growth. This opaque area messes with reading vision and significantly reduces vision in bright light. 
• Patients might see halos or glare around lights in general. Furthermore, this cataract will progress a lot faster than other cataracts.
• Congenital Cataracts: This is the type of cataract which is hereditary, either as a result of intrauterine trauma, infection, or genetic factors.