Cataract

What is Cataract?

A cataract is when the normally clear lens of the eye or its surrounding transparent membrane becomes cloudy. This blocks light from passing through to the retina, the part of the eye that sends images to your brain. Cataracts can cause vision loss and may lead to blindness. They can affect anyone, from babies to adults, but are more common in older people.

They can occur in either one or both eyes and the severity can vary. At first, you may not notice any changes to your vision because cataracts usually develop slowly. However, as you get older, especially after your 40s or 50s, cataracts continue to mature and can eventually make the lens entirely opaque, stopping light completely. This can interfere with everyday activities that depend on your sight.

Cataracts are a significant cause of blindness around the world. In the early stages, glasses may help with vision problems caused by cataracts. However, if the cataracts progress to the point of affecting daily life, a common and highly successful treatment is surgery.

What Causes Cataract?

Cataracts happen because of multiple factors, such as:

A congenital cataract is a cataract you’re born with and it can affect one or both eyes. Factors like the mother’s diet, infections like rubella and measles during pregnancy, or problems with blood flow to the baby while in the womb can contribute to this.

Age-related or senile cataract is the most common kind of cataract, usually developing as people get older.

Subcapsular cataracts form beneath the front and back layers, or capsules, of the lens of the eye. They can result in blurry vision and sensitivity to light.

Nuclear cataract affects the central part of the lens and are typically associated with aging. This leads to changes in your vision and may also cause a yellowish hue in the eye.

Cortical cataracts affect the surrounding part of the lens and can cause glare and light sensitivity.

Christmas tree cataracts are a rare type with shiny, multicolored aspects in the deeper part of the lens. This pattern of colors resembles the twinkling lights on a Christmas tree.

There are also levels of cataract severity, which include immature (partially cloudy lens), mature (completely cloudy lens), and hypermature cataracts (a shrunken, wrinkled lens due to fluid leakage).

The Morgagnian cataract is an advanced stage of a hypermature cataract where the lens’ outer layer liquefies and the inner part sinks downwards.

Eye injuries from things like perforation or blunt force are a common cause of cataracts in younger adults, as are other less common causes like electric shocks and harmful radiation. Certain chemicals can also cause cataracts.

There are also some illnesses and medical conditions that can lead to cataracts. These include diabetes, where high glucose levels can cause a rapid onset of cataracts in younger patients; Myotonic dystrophy and Atopic dermatitis, which can cause significant cataracts by middle age; and Neurofibromatosis type 2, where cataracts can develop in early adulthood.

Some other causes include being unable to control your body’s calcium levels or having abnormal thyroid glands. Finally, cataracts can also occur as a result of other eye diseases or high eye pressure, and are regularly seen in people with severe nearsightedness or genetic eye disorders.

Certain lifestyle choices, like a poor diet or heavy alcohol and tobacco use, can also contribute to the development of cataracts.

Risk Factors and Frequency for Cataract

Cataracts are a condition that frequently affects people’s eyes, and studies have shown that their occurrence varies among different racial groups and genders, as well as with age.

• White Americans have the highest rates of cataracts, with 17 to 18 out of every 100 people affected.
• Black individuals have the second highest rates, with a prevalence of 13%.
• Hispanics follow, with a prevalence rate of nearly 12%.
• Cataracts gradually develop, usually in older individuals, specifically those in their 50s and 60s. However, they can also occur in children and the elderly.
• Recent studies have found that cataracts are more common in women than in men, with the ratio of men to women being roughly 1 to 1.3.

Signs and Symptoms of Cataract

The patient could show a range of symptoms, which can include:

• Fading or blurry vision, this can happen gradually and painlessly, affecting one or both eyes, this happens even when wearing glasses
• Seeing double or multiple visions, mostly from one eye but can also be from both, this is due to light refracting or bending in different directions due to clear areas among the clouded parts of the eye
• Colorful halos around lights, such as a rainbow halo, this might be a result of the lens of the eye separating light into different colors, similar to a prism
• Light sensitivity, especially to bright lights from car headlights and the sun
• Frequent need to change prescription glasses because as the eye condition worsens the person may need to visit the eye doctor more often to correct their vision
• Disruptions in color vision, with colors fading or yellowing

During a detailed eye check, an eye specialist may observe the following:

• A decrease in vision in one or both eyes

If the patient has a type of cloudiness in the lens of the eye called cortical cataract, the doctor might notice:

• A blurriness shaped like a pie-piece with some clear areas of the lens often located at the outer part of the eye, this is the early stage of the cataract
• A well-formed pie-piece-shaped blurriness that is getting worse
• Early stage findings alongside a clouded lens, parts of the lens that still seem clear, and a shadow formed by the colored part of the eye
• A progressed condition with a lens that has filled up with fluid making the front chamber of the eye shallower
• A fully clouded lens with no shadow appearing from the colored part of the eye
• Condition moving towards the very advanced stage with a milky fluid-filled bag, cloudy lens, and the front chamber of the eye appearing shallow

If the patient has another type of these cloudy areas called nuclear cataract, the doctor might observe:

• A dark brown or black lens that casts a shadow
• Inability to see into the back of the eye due to a dark blurry area in the center
• Absence of a light reflection from the eye

Systemic diseases can also cause these types of cataracts:

• Diabetes can cause specific snowflake-like cloudiness in the lens
• Myotonic dystrophy might cause Christmas tree-like cataract, which later develops into star-like cloudiness in the lens
• Atopic dermatitis can cause specific dense patches at the front of the lens
• Neurofibromatosis type 2 might cause a mix of cloudiness types that can affect different parts of the capsule of the lens

Testing for Cataract

If you’re experiencing problems with bright lights, have difficulty seeing at night, struggle to read fine prints, or have blurry vision at a distance, it may be due to cataracts. A change in the clarity of your eyes’ lenses often causes cataracts. If you have these issues, your doctor might recommend cataract surgery.

Your doctor will need to take a complete drug history to understand any medications you’re taking that could affect your eyes. For example, certain medications like tamsulosin, commonly used to treat an enlarged prostate, can cause what’s known as intraoperative floppy iris syndrome (IFIS), which can make the surgery more complicated.

If you’re taking any blood-thinning medications, some doctors might recommend stopping these about 3-5 days before the operation. Also, you should let your doctor know about any allergies you have, particularly to medications, iodine, or shellfish, as these can affect the types of medication or antiseptics used during surgery. If you have a latex allergy, that will mean using latex-free gloves during the procedure.

Once you’ve discussed your medical history, the doctor will then conduct a full assessment of your eyes. This will include checks for how well you can see both close up and at a distance, the strength of the muscles that control your eyes, how your pupils respond to light, and the overall health of the outer parts of your eyes. They’ll also check the health of your cornea (the clear front surface of your eye), the anterior chamber (the front segment of your eye), and the lens of your eye – where the cataract forms.

Lastly, the retina (the lining at the back of your eye that senses light and sends images to your brain) will be evaluated, and if there are concerns about its health, an ultrasound might be done. Any issues with your eye’s lens or retina could influence the success of cataract surgery.

Once the evaluation is complete, your doctor will take measurements of your eye, known as biometry, to calculate the power of the artificial lens (intraocular lens, or IOL) that will replace your natural lens during cataract surgery. This is done using special equipment that maps out the curvature of your cornea and measures the length of your eye.

If you’ve previously had eye surgery to correct your vision, it can affect the calculations for the lens you’ll need for cataract surgery. It’s also important to stop wearing contact lenses for at least a week before these measurements are taken as they can temporarily alter the shape of your cornea.

During cataract surgery, the IOL will be inserted into the lens capsule, which is the part of the eye that holds your lens in place. Various designs of IOLs are available, including flexible or rigid IOLs, those with special filters or coatings, or those that are designed to correct other vision issues such as astigmatism or presbyopia.

It’s crucial to discuss the surgery and IOL options with your doctor thoroughly before making a decision. This is known as informed consent, and it requires understanding the potential benefits, risks, and complications associated with cataract surgery.

Treatment Options for Cataract

The right treatment for cataracts depends on how much they’re affecting your ability to do everyday tasks. There are a few treatment options available:

If your sight isn’t too badly affected (if you have a visual function of 6/24 or better), you might not need surgery. Eye drops that dilate your pupil or prescription glasses can suffice to help with your daily activities. In some cases, cataract-dissolving drops are also used.

However, if your sight is worse than 6/24 or if the cataract is harming your eye’s health, such as causing a type of glaucoma or retinal detachment, surgery is needed.

If the cataract is present since birth and isn’t severely affecting your vision (i.e., visual function is more than 6/24), you can manage with prescription glasses. If vision drops below 6/24, surgery would be required. During surgery, the surgeon can remove the lens or replace it with an artificial one, depending on the severity of your condition.

When it comes to older-age cataracts, no medical treatment is effective once they’ve fully developed. Since these cataracts harden the lens nucleus, removing the lens by one of several methods is the usual treatment. Techniques include extracapsular and intracapsular cataract extraction as well as laser phacolysis, which is a new method currently under testing. It’s also possible to emulsify the lens, which can speed up recovery and cause less blurring.

Sometimes, the general health of a patient needs to be considered before cataract surgery. Conditions like diabetes, high blood pressure, heart issues, respiratory infections, hepatitis, AIDS, epilepsy, Parkinson’s disease, rheumatoid arthritis, and others need to be managed before surgery to ensure the best outcomes.

Different surgeries have different procedural steps. In manual small incision cataract surgery, steps include making small cuts to the eye, removing the lens, and possibly implanting an artificial one. In phacoemulsification, the surgeon makes an incision, breaks up, and suctions out the cataract. Then an artificial lens is implanted. In both surgeries, the eye is cleansed and the incision is closed afterwards.

What else can Cataract be?

When diagnosing cataracts, doctors don’t just look at cataracts, they also consider other eye disorders that can possibly cause similar symptoms. These include:

• Glaucoma
• Refractive errors (like near-sightedness, far-sightedness, and astigmatism)
• Macular degeneration (a disease that causes loss of vision in the middle of the visual field)
• Diabetic retinopathy (a diabetes complication that affects eyes)
• Corneal dystrophies (group of genetic, often progressive, eye disorders that affect the cornea)
• Optic atrophy (damage to the optic nerve which transmits images to your brain)
• Retinitis pigmentosa (group of rare, genetic disorders that involve a breakdown and loss of cells in the retina)

It’s crucial for the doctor to carefully review these conditions to make the correct diagnosis.

What to expect with Cataract

The prognosis, or expected outcome, of cataract surgery depends on many factors, including:

* How much the vision was affected
* The type of cataract
* The timing of the treatment
* The treatment method
* The patient’s overall quality of life
* Whether one or both eyes are affected
* The presence of another disease affecting the whole body

In most cases, surgery is a very effective way to restore vision. Other medical conditions, when the treatment takes place, and the method of surgery can also play a part in how successful the surgery is likely to be.

Recent studies have shown that for most people, the outcome after surgery is very good – successful in about 70 to 80% of cases. Most patients can expect excellent results if they follow the aftercare instructions and medication plan set by their eye doctor very strictly.

It’s a good idea to have regular eye check-ups to spot any development of a cataract in the other eye. Some patients with a single-eye lens implant might need glasses to get the best visual acuity, or clearness of vision, after having a cataract removed surgically.

Over time, a large number of patients may develop a gradual clouding of the section of the lens covering the back of the eye. This could affect their vision and is sometimes referred to as a secondary cataract.

Possible Complications When Diagnosed with Cataract

Cataracts can lead to several problems which fall into two categories: those present from birth (congenital) and those developed over time (acquired).

Congenital cataracts are often related to either the disease itself or the surgery required to treat it. Disease-related issues can include corneal ulcers, physical breaches in the cornea, and even blindness. Surgery to treat congenital cataracts can lead to inflammation of the uvea, thickening of the back part of the lens capsule, absence of lens in the eye after surgery, changes in vision related to growth, increased pressure in the eye (glaucoma), and detachment of the retina.

Similar to congenital cataracts, complications from acquired cataracts can arise from the disease or the surgery. Disease-related complications can include acute pressure buildup in the eye, inflammation of the iris, and relocation of the lens. Surgery complications can include breakage of the back part of the lens capsule, collection of blood in the eye, and corneal burns.

Post-surgical complications may emerge such as: iris popping out, delayed formation of the front chamber of the eye, infections like endophthalmitis or panophthalmitis, misplaced intraocular lens, increased pressure in the eye, retinal detachment, and cloudy vision.

Potential complications:

• Disease-related: corneal ulcers, breaches in the cornea, blindness (congenital)
• Surgery-related: uvea inflammation, lens capsule thickening, lens absence (congenital)
• Disease-related: pressure buildup in the eye, iris inflammation (acquired)
• Surgery-related: back part of the lens capsule breakage, blood collection in the eye (acquired)
• Post-surgery: iris popping out, delayed front chamber formation, infections (endophthalmitis or panophthalmitis), misplaced intraocular lens, increased eye pressure, retinal detachment, cloudy vision

Recovery from Cataract

After cataract surgery, patients will typically be prescribed eye drops that include steroids and antibiotics. Additional medications like cycloplegics and lubricants can be used if necessary. Steroid eye drops like 1% prednisolone and 0.1% dexamethasone are used in gradually decreasing doses over a period of six weeks.

The patient’s condition will be checked on the first day after surgery, and then again on day 30. Regular follow-up appointments are important to make sure no complications have occurred. At the one month mark after surgery, the patient will be evaluated for potential issues like Irvin Gass syndrome and post-operative iritis, which refers to inflammation of the iris. An eye test will be conducted to determine whether any adjustments in vision prescription are needed.

It is crucial for patients to understand the importance of attending regular follow-up appointments and using their prescribed eye drops on schedule.

Preventing Cataract

The doctors will provide patients with information about several aspects of their condition, such as:

• What can increase their chances of getting the disease
• Possible health issues that can occur as an effect of the disease
• Different ways to treat the disease
• Potential risks associated with the surgery
• The importance of regular check-ups after the treatment

Also, regular eye tests using charts to check sharpness of vision (visual acuity charts) and a special microscope to examine the eye (slit-lamp examinations) are recommended at each follow-up to track any change in vision after a cataract or to catch any problems that might have come up due to the surgery.

Patients should also consider wearing glasses when out in sunlight to protect their eyes from harmful ultraviolet (UV) rays. Alongside this, it’s a good idea for patients to have a complete check-up of their overall health to identify any other diseases that might affect the results of their treatment.