Timely eye examination for cataracts symptoms can help provide early cataracts treatment to improve vision. Read more from ophthalmologists at Meri Sehat.

Cataract

Cataracts

Humza Khizer

Overview

<p dir="ltr">A cataract is a disease of the eye that is characterized by an opacified lens, which is normally clear and obscures the passage of light.</p>

<p dir="ltr">The term cataract means &ldquo;huge waterfall&rdquo; because that is how people describe their clouded sight, trying to look through a waterfall. A cataract is a gradual, progressive disease that is a significant cause of blindness around the world. The eye&rsquo;s lens is a clear structure with the function of focusing images on the light-sensitive retina. Whereas, a cataract is defined as the clouding of the lens, distorting or blocking of the passage of light through the lens. This leads to cloudy or blurred vision with other visual problems and even blindness.&nbsp;<br />
<br />
Cataract generally affects older age groups, and it takes years for the clouding of the lens to keep the light from reaching the retina and distorting the light rays. The condition first appears in the 40s or 50s. However, it may not affect the vision till much later. Cataracts may be caused by an injury to the eye, radiation treatment, use of corticosteroids, or long-term diabetes. Though, some babies may be born with cataracts because of an infection that may have occurred during pregnancy, for example, herpes simplex, rubella, syphilis, cytomegalovirus, and toxoplasmosis. In infants and young children, cataracts may also be a symptom of diseases that affect the body&rsquo;s processing of copper, calcium, amino acids, and carbohydrates. Cataracts are a leading cause of blindness in the world, accounting for half the reported cases of blindness.&nbsp;</p>

<p dir="ltr"><br />
According to American research journals, the prevalence of cataracts ranges from 17% to 18% per 100 people and is more commonly seen in white people<sup><a href="#accordion">[1]</a></sup>. Black people are the second-highest race affected by cataracts with a prevalence rate of 13%, followed by Hispanics with a rate of almost 12%<sup><a href="#accordion">[1]</a></sup>. The onset is gradual and progressive. While cataracts are commonly seen in the older age group, cases in children have also been reported. Recent studies have also postulated that the disease is more common in women than in men, with a ratio of 1 to 1.3, approximately. In addition, findings from the Pakistan National Blindness and Visual Impairment Survey report in which a total of 16,507 adults were examined, a total of 4416 participants were identified with bilateral blindness because of cataracts<sup><a href="#accordion">[2]</a></sup>. Cataracts were identified as the main cause of blindness in 66% of patients in a study conducted between 1987 and 1990<sup><a href="#accordion">[3]</a></sup>. Moreover, approximately 14,000 cataract surgeries were performed in 1994 by 500 ophthalmologists in Pakistan<sup><a href="#accordion">[2]</a></sup>. However, this figure might be an underestimation due to the lack of collection of cataract data on a national level.</p>

<p dir="ltr">&nbsp;</p>

<p dir="ltr">Cataracts are caused when there is a buildup of protein in the lens of the eye making the vision cloudy. This buildup of protein prevents light from passing through the eye clearly and can cause a loss of eyesight. There are different types of cataracts.&nbsp;&nbsp;<br />
&nbsp;</p>

<ul>
	<li>
	<h5><strong>Nuclear Cataracts</strong></h5>
	</li>
</ul>

<p dir="ltr">Nuclear cataracts are also known as sclerotic cataracts and are the most common type of cataracts. Cataracts form in the nucleus of the lens, or the center of the lens. While it causes the vision to get worse, it may improve your reading vision. This phenomenon is called second sight; however, it does not last very long. With time, the lens hardens and may become yellow or even brown, making it difficult to see small details. For example, you may see halos around objects or colors may appear less rich.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Brunescent Cataracts</strong></h5>
	</li>
</ul>

<p dir="ltr">Brunescent cataracts occur when a nuclear cataract is left untreated, and the cataract turns hard and brown. A characteristic feature of this type of cataract is the inability to differentiate between colors, especially blues, and purples. Surgical removal of brunescent cataracts is more difficult and riskier.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Cortical Cataracts</strong></h5>
	</li>
</ul>

<p dir="ltr">The term cortical means relating to the outer layer of the eye. As the name suggests, cortical cataracts form on the cortex of the eye, the part which is outside the edge of the lens. Cataracts begin as white triangles that point towards the center of the eye and as they grow, they scatter light. A characteristic feature of cortical cataracts is that the vision may become hazy. Cortical cataracts make it difficult to drive at night, tell the difference between colors, and/or judge how far an object is.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Posterior Subscapular Cataracts</strong></h5>
	</li>
</ul>

<p dir="ltr">This type of cataract forms inside the back of the lens capsule. The capsule is an outer covering of the lens that holds it in place. Light passes through this capsule and then through the lens. In the case of posterior subscapular cataracts, symptoms may appear within months, affecting close-up vision and making it more difficult to see a bright light.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Anterior Subscapular Cataracts</strong></h5>
	</li>
</ul>

<p dir="ltr">The anterior subscapular cataract forms inside the front of the lens because of an injury or swelling in the eye.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Congenital Cataracts</strong></h5>
	</li>
</ul>

<p>The term congenital means a disease or physical abnormality that is typically present from birth. Thus, this type of cataract is present since birth. In addition, it is either linked to genes or is because of an illness such as rubella that the mother may have had during pregnancy. A small cataract is present outside the center of the lens, and may not require treatment. However, in some cases, cataracts can block vision, requiring surgery.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Traumatic Cataracts</strong></h5>
	</li>
</ul>

<p>There are many types of injuries that can cause cataracts, for example, traumatic injuries, chemical injuries, or a burn. The cataract may either show soon after the injury or a few years later.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Secondary Cataracts</strong></h5>
	</li>
</ul>

<p>This type of cataract is secondary to a medical condition, such as diabetes, or treatment with steroids like prednisone. In some cases, cataract surgery may also cause secondary cataracts.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Radiation Cataracts</strong></h5>
	</li>
</ul>

<p>It is as important to protect the eyes from the sun&rsquo;s ultraviolet (UV) rays as it is to protect the skin. If you spend too much time in the sun without eye protection, then UV rays can damage the eyes and cause cataracts. Radiation cataracts are commonly seen in farmers and fishers. However, cataracts can also be a side effect of radiation therapy for cancer.</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Lamellar Or Zonular Cataracts</strong></h5>
	</li>
</ul>

<p>A lamellar cataract is a type of cataract that affects both eyes in young children. This is an inherited disorder passed down from parents to children. A characteristic feature of this type of cataract is the presence of fine white dots in the middle of the lens which may form a Y shape. After some time, the whole center of the lens may turn white.&nbsp;<br />
&nbsp;</p>

<ul>
	<li>
	<h5><strong>Posterior Polar Cataracts</strong></h5>
	</li>
</ul>

<p>This cataract affects the lens&#39;s center and is also inherited. In most cases, the cataracts are asymptomatic (showing no symptoms), and don&rsquo;t require removal.&nbsp;<br />
&nbsp;</p>

<ul>
	<li>
	<h5><strong>Anterior Polar Cataracts</strong></h5>
	</li>
</ul>

<p>In this type of cataract, the center of the lens looks like a small white dot but does not bother the vision.&nbsp;<br />
&nbsp;</p>

<ul>
	<li>
	<h5><strong>Post-Vitrectomy Cataracts</strong></h5>
	</li>
</ul>

<p>A vitrectomy is a type of surgery for the treatment of various problems in the retina and vitreous humor, a clear gel at the center of the eye. A postoperative complication of the surgery includes cataracts.&nbsp;</p>

<p>&nbsp;</p>

<ul>
	<li>
	<h5><strong>Christmas Tree Cataracts</strong></h5>
	</li>
</ul>

<p>This type of cataract is also known as a polychromatic cataract. It causes the formation of shiny, colored crystals in the lens. They are commonly seen in people with myotonic dystrophy, an inherited disorder that causes muscular dystrophy. This is a condition in which the muscles of the body weaken progressively, causing loss of muscle mass.&nbsp;<br />
&nbsp;</p>

<ul>
	<li>
	<h5><strong>Diabetic Snowflake Cataracts</strong></h5>
	</li>
</ul>

<p>Diabetic snowflake cataracts are rare and only occur in diabetic patients. Cataracts tend to worsen quickly and form a grey, white pattern on the eye, which looks like a snowflake.&nbsp;</p>

<p>&nbsp;</p>

Signs And Symptoms

<p dir="ltr">Cataracts are generally asymptomatic until they have increased in size and interfere with vision. The symptoms of cataracts include:&nbsp;</p>

<ul>
	<li>Blurry or cloudy vision&nbsp;</li>
	<li>Double vision&nbsp;</li>
	<li>The faded appearance of colors&nbsp;</li>
	<li>Seeing halos around objects or lights&nbsp;&nbsp;</li>
	<li>Increased sensitivity to light and glare&nbsp;</li>
	<li>Difficulty with vision at night&nbsp;</li>
	<li>Frequently changing eyeglasses or contact lenses prescription&nbsp;</li>
</ul>

<p>&nbsp;</p>

Causes

<p dir="ltr">Most cataracts occur when the tissue of the eye&rsquo;s lens changes either because of aging or an injury to the eye. The proteins and fibers in the lens break down and cause the vision to become blurry or hazy. Studies have shown that certain inherited genetic disorders and health problems can increase the risk of cataracts. Cataracts can also be caused because of other eye conditions, or medical conditions, such as diabetes or eye surgery. In some instances, the long-term use of steroids may also lead to the development of cataracts.&nbsp;</p>

<p dir="ltr">&nbsp;</p>

<p dir="ltr">The lens of the eye is located behind the iris (the colored part of the eye), and a cataract is described as an opacified, blurry, hazy, or cloudy lens. The function of the lens is to focus the light that passes into the eye to form clear and sharp images on the retina. However, as you age, the lens in your eye becomes less transparent, less flexible, and thicker. Aging and certain medical conditions cause the proteins and fibers in the lens to break down and clump together. Therefore, causing the lens to opacify. In addition, the opacification becomes worse when the cataract continues to become larger. The cataract blocks light from passing through the lens and prevents defined images from reaching the retina. This causes your vision to become blurred. Cataracts are generally bilateral. However, cataracts in one eye may advance at a faster rate than the other, causing a difference in vision between eyes.&nbsp;</p>

<p dir="ltr">&nbsp;</p>

<p dir="ltr">A cataract screening involves a comprehensive eye examination. The many aspects that play a role in the diagnosis and treatment of cataracts include:&nbsp;</p>

<h5 dir="ltr"><br />
<strong>Medical History&nbsp;</strong></h5>

<ul>
	<li>Patient&rsquo;s medical history and family history.&nbsp;</li>
	<li>Use of prescription and non-prescription medications.&nbsp;</li>
	<li>History of smoking, high blood pressure, and sun exposure.</li>
</ul>

<h5 dir="ltr"><br />
<strong>History Of Issues In Vision&nbsp;</strong></h5>

<ul>
	<li>Current visual health with recent changes in vision.&nbsp;</li>
	<li>Family history of macular degeneration, glaucoma, etc.&nbsp;</li>
	<li>Previous history of eye injuries or surgeries.</li>
</ul>

<p dir="ltr">&nbsp;</p>

<h5 dir="ltr"><strong>Vision Acuity&nbsp;</strong></h5>

<ul>
	<li>Sharpness and clarity of distance vision.&nbsp;</li>
	<li>Eyeglass exam.&nbsp;</li>
	<li>Peripheral vision acuity.&nbsp;</li>
</ul>

<h5 dir="ltr"><br />
<strong>Overall Eye Health Evaluation&nbsp;</strong></h5>

<ul>
	<li>External examination of the eye using a slit lamp.&nbsp;</li>
	<li>Examination of the eye using an ophthalmoscope is recommended every 2 years for individuals over the age of 40. However, if there is a history of glaucoma, the test should be performed every year.&nbsp;</li>
	<li>Aqueous humor pressure test.</li>
</ul>

<p>&nbsp;</p>

Diagnosis

<p dir="ltr">Cataracts are diagnosed based on medical history, symptoms, and eye examination. The doctor may perform several tests, including:&nbsp;</p>

<h5 dir="ltr">&nbsp;</h5>

<ul dir="ltr">
	<li>
	<h5 dir="ltr"><strong>Visual Acuity Test&nbsp;</strong></h5>
	</li>
</ul>

<p>A visual acuity test is performed using a measuring chart with progressively smaller letters to measure how well you can read a series of letters. Using the chart, the eye doctor will determine if you have 20/20 vision or if there are signs of vision impairment.&nbsp;</p>

<h5>&nbsp;</h5>

<ul>
	<li>
	<h5><strong>Slit-lamp Examination</strong>&nbsp;</h5>
	</li>
</ul>

<p>A slit-lamp examination is used to check the structures in front of the eye under a microscope. The microscope uses intense light to illuminate the cornea, iris, lens, and the space between the iris and cornea to highlight any abnormalities.&nbsp;</p>

<h5>&nbsp;</h5>

<ul>
	<li>
	<h5><strong>Retinal Examination&nbsp;</strong></h5>
	</li>
</ul>

<p>A retinal examination is done to examine the back of the eye, the retina. The pupils of the eyes are dilated using drops and the lens is examined using an ophthalmoscope for signs of a cataract.&nbsp;<br />
&nbsp;</p>

<ul>
	<li>
	<h5><strong>Applanation Tonometry</strong>&nbsp;</h5>
	</li>
</ul>

<p>The test is used to measure the pressure of fluid in the eye.<br />
&nbsp;</p>

Treatment

<p dir="ltr">While you may not need surgery right away, it is the only way to treat cataracts. If the cataract is caught early, a new prescription for your glasses or a stronger lens may make vision better, but only for a while. If you have difficulty reading, a magnifying glass and brighter light may help. Additionally, special sunglasses with an antiglare coating may be helpful when you drive at night. However, if your vision problems are getting in the way of your daily routine, surgery may be the only treatment option.&nbsp;</p>

<p dir="ltr">&nbsp;</p>

<h5><strong>Cataract Surgery&nbsp;</strong></h5>

<p>Cataract surgery includes taking out the blurry lens and replacing it with an artificial one. The procedure takes about 20 to 30 minutes. If the cataract is in both eyes, the procedures are done a few days apart until the first eye heals. More than 95% of the people show full recovery after the surgery. The types of cataract surgery include:&nbsp;<br />
&nbsp;</p>

<ul>
	<li><strong>Small Incision Surgery Or Phacoemulsification</strong><strong> </strong>&ndash; In this procedure, the surgeon will make a tiny cut in the cornea and use a small device that gives ultrasound waves to break up the cloudy lens. Once this is done, the surgeon will take out the broken pieces and replace the lens with an artificial lens.&nbsp;</li>
	<li><strong>Large Incision Surgery Or Extracapsular Cataract Extraction</strong><strong> </strong>&ndash; This type of surgery is preferred for larger cataracts. In this procedure, the surgeon will surgically extract the clouded lens and replace it with an artificial lens.&nbsp;</li>
	<li><strong>Femtosecond Laser Surgery</strong> &ndash; In this type of operation, the surgeon will use a laser to break up the lens, but not put in a new lens as with the other types. A femtosecond laser surgery is recommended in case of astigmatism.</li>
</ul>

<p>&nbsp;</p>

<p dir="ltr">Cataract surgery goes smoothly for most people, but as with any other surgery, there are some risks associated with cataract surgery. Especially, if you have other medical conditions. These may include:&nbsp;</p>

<ul>
	<li>Infection&nbsp;</li>
	<li>Inflammation&nbsp;</li>
	<li>Retinal detachment&nbsp;</li>
	<li>Lens fragments&nbsp;</li>
	<li>Fluid buildup in the retina&nbsp;</li>
	<li>Dislocated intraocular lens&nbsp;</li>
	<li>Secondary cataract&nbsp;</li>
	<li>Swelling in the cornea&nbsp;</li>
	<li>Bleeding&nbsp;</li>
	<li>Floaters and flashes of light&nbsp;</li>
	<li>Increased eye pressure&nbsp;</li>
	<li>Light sensitivity&nbsp;</li>
	<li>Droopy eyelid&nbsp;</li>
	<li>Dysphotopsia, curved shadows or halos at the edge of your vision</li>
</ul>

<p>&nbsp;</p>

<p dir="ltr">The risk factors of cataracts include:&nbsp;</p>

<ul>
	<li>40 and 50 years of age</li>
	<li><a href="https://merisehat.pk/disease/diabetes-type-1-and-2">Diabetes</a></li>
	<li>Excessive exposure to sunlight</li>
	<li>Excessive smoking</li>
	<li><a href="https://merisehat.pk/disease/obesity">Obesity</a></li>
	<li><a href="https://merisehat.pk/disease/hypertension-57">High blood pressure</a></li>
	<li>History of eye injury or inflammation</li>
	<li>History of eye surgery</li>
	<li>Long-term use of corticosteroid medications</li>
</ul>

<p>&nbsp;</p>

<p>There is a lack of studies on what causes cataracts, and doctors don&rsquo;t exactly know what causes them. Therefore, there is no proven way to prevent them. However, because cataracts are common in older adults and in people with a family history of eye problems, it is important to get your eyes checked regularly if you have a history of eye problems or other medical conditions. In conclusion, a history of eye problems and medical concerns such as diabetes increases the risk of eye disease.&nbsp;</p>

<p dir="ltr">&nbsp;</p>

Key Points

<ul>
	<li>A cataract is a disease of the eye that is characterized by a cloudy lens and blurred vision.&nbsp;</li>
	<li>The condition is more commonly diagnosed in the 40s and 50s.&nbsp;</li>
	<li>Cataracts may be caused because of an injury to the eye, radiation treatment, use of corticosteroids or long-term diabetes. However, some babies may also be born with cataracts because of an infection during pregnancy.&nbsp;</li>
	<li>Currently, surgery is the only treatment for cataracts.&nbsp;</li>
</ul>

<p>&nbsp;</p>

[1] Nizami, A.A., Gulani, A.C. and Redmond, S.B., 2021. Cataract (Nursing).

[2] Jadoon, Z., Shah, S.P., Bourne, R., Dineen, B., Khan, M.A., Gilbert, C.E., Foster, A., Khan, M.D. and Pakistan National Eye Survey Study Group, 2007.