Cataracts is the clouding of the eye due to protein build up. It is commonly associated with the aging population, however it can also be associated with a variety of different medical conditions other than aging. In order to better understand cataracts, it is essential to understand the anatomy of the eye and how the progression of cataracts occur.

Anatomy Of The Eye

Each eye has a lens that is located behind the iris (the colored portion of the eye). The lens has three segments which include; the outer capsule, the cortex, and the inner nucleus. Cataracts can form in any of these layers of the lens.

When a cataract forms in a specific layer of the lens it impedes an individual’s vision. Cataracts form in the lens of the eye and cause vision changes such as blurred or double vision by inhibiting light from entering the eye normally. Because it does not affect the retina, when the cataract is removed the patient’s visual acuity becomes immediately better.

If there is damage to the retina in addition to cataracts then even if the cataract is removed, a person’s vision will not change very much. Cataract removal will only improve the person’s vision if the cataract is impeding the light through the lens to the retina.

Different Types Of Cataracts:

There are many different types of cataracts including: nuclear sclerotic cataracts, posterior sub-capsular cataract, congenital cataracts, traumatic cataract, posterior capsular opacification, and diabetes associated cataracts.

Nuclear Sclerotic Cataracts:

These are the number one cause of cataracts in the aging population.  Over time the normal lens of the eye becomes larger and changes color.  An opacity begins to form in the nucleus of the lens and becomes opaquer as an individual ages.  When this occurs, it begins to slowly impede an individual’s ability to see.  As the opacity grows and becomes larger it can completely impede one’s ability to see using that eye. 

Posterior Sub-capsular Cataract:

This particular subset of cataracts usually occurs in patients with a past medical history of diabetes or other inflammatory diseases that may require steroid treatment.  The PSC cataract forms on the inner surface of the posterior capsule.  Because this type of cataract occurs on the posterior surface of the capsule, it can be difficult to visualize and significantly impedes the individual’s vision.

Congenital Cataracts:

There are a variety of medical conditions that can have cataract formation as a complication.  Rare childhood cancers such as Retinoblastoma can result in cataract formation.  If a cataract is seen in a child, it is imperative that this disease be ruled out.  Cataracts are just a symptom of retinoblastoma, which is a deadly disease and must be treated appropriately by the specialized physicians.  Other diseases such as TORCh infections and Galactosemia can also result in cataract formation.  In these serious medical conditions it is imperative that the underlying disease be treated first and then the cataracts addressed.

Traumatic Cataracts:

In instances in which the lens capsule is ruptured by some outside traumatic force, the inner lens becomes swollen and opaque.  When this occurs, the cataract is best addressed by removing the lens and replacing it with an artificial lens.

These are just a few of the different types of cataracts that can form.  The key takeaway message is that cataracts can form in the anterior lens or the posterior portion of the lens.  Wherever the cataract forms in the lens, it will have negative effects on the patient’s vision.  Cataracts can be associated with the aging, congenital, or traumatic conditions.  Whatever the cause, the intervention is the same.  To remove the cataract and replace the lens with an artificial lens.  Intervention is different for small children or others who have an underlying medical condition resulting in cataract formation.  Therefore, it is essential that each patient discuss their unique case with an Ophthalmologist to determine an individualized treatment plan.

Symptoms & Risk Factors of Cataract

The most commonly associated symptom with an advanced cataract is the impact it has on the individual’s vision.  Many patients have compared cataracts to having a smudge on the end of a camera lens in which they cannot remove.  That smudge impedes their ability to see and only becomes worse over time. 

Other symptoms include blurred vision, inability to see at night while driving, inability to see when there are situations that have a high glare (i.e. headlights, bright sunny days), and diminished sharpness of color. 

As the cataract progresses, the patient may also complain that their vision is constantly and consistently getting worse. These patients may present to the physician with the complaint that their current glasses prescription is no longer strong enough.  Some patients experience symptoms of double vision, sensitivity to light, dim vision, need for increased light during reading, seeing halos around bright lights (i.e. headlights of a car), and/or yellowing of colors.

Risk Factors For Developing Cataracts:

Aging is a natural process that affects the lens of the eye.  This aging process is slow and creates the progressive development of cataracts.

Other risk factors include diabetes, smoking, obesity, high blood pressure, traumatic eye injury, eye inflammation, eye surgery, long-term steroid use, and increased consumption of alcohol.  These factors plus many more can place an individual at an increased risk of developing cataracts.

Diagnosis of cataract: 

In order to be diagnosed with a cataract it is essential that as a patient you follow up with your Ophthalmologist.  Being aware of the risk factors and the signs/symptoms of cataract development will help one to seek intervention more quickly.  There are several specific examinations that the Ophthalmologist will perform in order to determine if the cataract is the cause of the disturbance in vision. 

The first test is known as a visual acuity test.  This test uses the big eye chart that measures how well an individual can visualize the letters on the chart.  Each eye is first tested independently of the other.  The physician will have you read the smallest, clearest line from left to right beginning with the right eye and then with the left eye.  The physician will then determine the results of this visual acuity test and determine if you have 20/20 vision in each eye.  If there is a visual disturbance, the visual acuity test will show those specific signs.

The ophthalmologist will then evaluate each eye using a slit-lamp.  The slit-lamp evaluation allows the Ophthalmologist to evaluate the external structures of the eye, including the lens.  The slit lamp is a microscope that magnifies the external eye structures. The slit lamp is used to examine the cornea, iris, lens, and chamber between the iris and cornea.  During this test the physician will be able to determine if the patient has cataracts and how advanced those cataracts are.

Finally, the physician will perform a retinal examination.  Using an ophthalmoscope, the physician will evaluate the back of the eye where the retina is located.  Understanding the structure of the retina and its involvement in the production of vision, will help determine if the cataract or retinal damage is the cause of the visual disturbances.  If there is not any retinal pathology and there is a cataract present, then in many cases the visual acuity will be tremendously improved with the removal of the cataract.  If there is retinal pathology, the improvement in visual acuity will be based on the severity of that underlying pathology.

Treatment of cataract: 

Cataracts result in visual disturbances that can be alleviated with surgical intervention.  The Ophthalmologist will perform the surgery and remove the cataract. There are two types of surgeries that will be based on your individualized treatment plan.

If the patient is high risk or has other medical conditions that interfere with the ability of the surgeon to replace the anatomic lens with an artificial intra-ocular lens, then the cataract will be removed and the vision will be corrected using contact lenses or glasses. In most cases however, when the cataracts are removed from the eye, the anatomic lens is removed and replaced with an intra-ocular lens.  This intra-ocular lens will correct the patient’s vision, creating 20/20 visual acuity in most patients.  If 20/20 is unattainable because there is other eye pathology present, then the vision will be corrected as realistically as possible giving the specific circumstances.

There are a variety of different intra-ocular lens types that will offer a spectrum of benefits. Therefore, it is imperative when determining if cataract surgery is the best option for your visual needs, to discuss the different intra-ocular lens types available that would provide you with the best possible outcomes.  Intra-ocular lenses are made of either silicone or acrylic.  Some of the different types of intra-ocular lens types include:  Monofocal IOLs, Multifocal IOLs, Accommodative IOLs and Toric IOLs. 

Monofocal Intra-Ocular Lens (IOLs):

The Monofocal IOLs is the most commonly inserted IOL for patients during cataract removal surgery.  It offers one focusing distance.  That focus can be either up close, medium, or long distance.  The patient will determine which type of vision they wish to have corrected with the IOL and then most individuals will have to supplement their vision with glasses or reading glasses.  To determine which type of visual adjustment is most appropriate for your individual case, please speak with your Ophthalmologist. 

Multifocal Intra-Ocular Lens (IOLs):

Multifocal IOLs are IOLs that provide both distance and near focus simultaneously.  The lens has different areas that have different preset powers. The brain learns to interpret this information allowing for automatic focusing.  It takes a little bit of time for the brain to make this adjustment, so it is imperative to follow up with your Ophthalmologist to determine if this type of IOL is most appropriate for your individual case. 

Accommodative IOLs and Toric IOLs:

Accommodative IOLs are IOLs that change shape to allow focus at a variety of distances.  For patients with astigmatism the Toric IOL may be the best IOL option post cataract removal.  The Toric lens addresses the uneven curvature of the cornea or lens to allow for correction of the astigmatism. 

Cataract Removal Surgery:

The cataract removal surgery can be done outpatient in a surgery center.  In many cases, if there is cataracts in both eyes, the surgery is performed on one eye and then after that eye heals, surgery is scheduled to remove the cataract from the other eye.

As with any surgery there are associated risks. Risks associated with cataract surgery may include but are not limited to the following:  eye infection, bleeding into the eye; swelling of the outside, inside or front of the eye; swelling of the retina; detached retina, damage to the other structures of the eye; pain in the eye, vision loss, dislocation of the intra-ocular lens. 

Over time the new intra-ocular lens may begin to build up deposits that create cloudy vision post cataract removal.  If this occurs a posterior capsulotomy can be performed in which a laser will break up these deposits that have build up on the intra-ocular lens.  The posterior capsulotomy procedure will help to create a clear visual field providing that there is not any other underlying eye pathology.

Each individual is unique and responds to surgery differently.  Therefore, it is imperative to speak with your Ophthalmologist so that an appropriate individualized plan of care can be established. Once an individualized plan of care has been established then appropriate intervention can be suggested. 

Conclusion:

After reviewing the above information regarding cataracts, it is our hope that as a patient you will be more aware of the necessary steps you must take to address your visual acuity.  Cataracts can impede one’s visual acuity tremendously.

With that being said, cataracts are also easily removed and can provide an immediate resolution of any visual disturbance contributed to its presence.  If you have noticed any of these symptoms, then there is a chance that cataract formation may be the culprit of any visual disturbance.  At this point, it is necessary for you to follow up with your Ophthalmologist so that an appropriate treatment plan can be established. 

Treatment includes the removal of the cataracts through surgical intervention.  Your physician will discuss the risks and benefits of having these cataracts removed.  Together you and your physician can make an educated determination of the most appropriate next steps for your individualized care.