Cataract In Diabetes Mellitus: Risks, Treatment, and Complications

Cataract and diabetes are two terms commonly brought up together in someone’s medical history. An increase in the incidence of one of these can mark an increase in the other. Specifically, diabetes mellitus is the kind of diabetes that is frequently associated with cataracts. While researchers have already conducted several studies to understand the connection between the two, the root cause is still marked with a big question mark. Even when presented with this ambiguity, doctors can proceed with treating cataracts in a safe surgical operation. However, it still stands that multiple complications can occur after treatment. Let us find out the specifics between cataracts and diabetes mellitus.

Background Check: Cataract And Diabetes Mellitus

Cataract forms in an eye when proteins in the eyes clump together, commonly due to aging. People looking at your eyes can see some sort of cloudiness in the lens of your eyes, while your vision blurs because of this cloudiness. 

On the other hand, we have a seemingly unrelated disease. Diabetes mellitus, simply known as diabetes, is a chronic disease affecting all parts of the human body. It is generally characterized by a disorder in the body regarding insulin production. There are two major types of diabetes mellitus:

  • Type I: an autoimmune disease causing damage to the pancreas, making the body unable to produce insulin.
  • Type II: systemic dysfunction throughout the body that results in a net increase in blood glucose levels.

Among the symptoms of the disease, these are the ones commonly found in both type I and type II diabetes mellitus:

  • Polyuria: uncontrollable and excessive urination
  • Polydipsia: uncontrollable and excessive thirst
  • Polyphagia: uncontrollable and excessive eating
  • Vision impairment: typically exhibited through the blurring of vision

Although eye impediments and blood sugar levels can appear to be completely different from one another, symptoms of diabetes include vision impairment. In addition, several studies actually correlate diabetes mellitus to cataract formation. Moving forward, we will be discussing cataracts and diabetes mellitus in a 2019 article published by the World Journal of Diabetes.

How Does Diabetes Mellitus Accelerate Cataract Formation?

While the common formation of cataracts occurs through aging, it can also happen to individuals at an early age due to diabetes mellitus. In fact, these children are five times more likely to develop cataracts. Scientists are yet to pinpoint the exact reasons. However, these are the proposed explanations:

  1. The polyol pathway accumulates sorbitol into blood cells leading to a water imbalance between the blood and the lens fibers in the eyes, making the cells swell. These swollen fibers degenerate and form cataracts. 
  2. Some studies suggest that this sorbitol accumulation can cause automated cell death in the epithelial cells of the eyes, which then leads to cataract formation.
  3. Glucose level fluctuations in the blood initiate protein unfolding in the endoplasmic reticulum of the lens fiber and causing damage to it. These damages can form cataracts.
  4. Some scientists suspect an autoimmune dilemma because they found insulin autoantibodies in patients who started insulin treatment. The presence of these autoantibodies coincided with the formation of cataracts in the patients.

Incidence and Risk of Cataract on Patients with Diabetes Mellitus

As previously mentioned, the incidence rate for children with diabetes mellitus is five times more likely than the normal population. This falls under the category of pediatric cataract. In non-pediatric individuals under the age of 65, patients with diabetes mellitus are three to four times more likely to develop cataracts. On the other hand, those who have aged over 65 years old and have diabetes mellitus are twice as likely to develop cataracts.

Now, if you have diabetes mellitus, the major risk factor for cataract formation is age. Additionally, these are some risk factors to take note of if you have type I diabetes mellitus:

  • Longer durations of diabetes can incur higher chances of developing cataracts.
  • Poor metabolic control (as defined by the American Diabetes Association):
    • Poor glycemic control: average blood glucose levels of more than 7%
    • Poor blood pressure control: blood pressure higher than 140/90 mmHg
    • Poor LDL-cholesterol control: Low-density lipoprotein (LDL) levels of more than 100 mg/dL
  • Development of a severe case of diabetic retinopathy caused by high blood glucose levels
  • Proteinuria: diagnosed with increased protein levels in the urine

Current State of Cataract Treatment in Patients with Diabetes Mellitus

Having discussed the signs, symptoms, causes, incidence rates, and risk factors, we move on to treating cataracts, specifically in those patients with diabetes mellitus. Doctors are particularly concerned with those with diabetes mellitus because complications can arise when treating cataracts in patients with this disease. 

The usual treatment for cataracts is removal surgery. However, when paired with diabetes mellitus, this surgery has risks of rapid progression of diabetic retinopathy leading to decreased or even complete loss of vision. Because of this, patients may opt to postpone surgery when their doctors detect diabetic retinopathy. More recent medical research suggests phacoemulsification cataract surgery, but the risk of retinopathy acceleration still persists. 

Due to these complications that present when treating cataracts in patients with diabetes mellitus, medical professionals stress the importance of preoperative evaluation and postoperative management apart from the actual treatment.

Preoperative evaluation involves meticulous assessments for the insurance of a safe operation. You may expect the following tests:

  • Best-corrected visual acuity (BCVA)
  • Slit Lamp Biomicroscopy
  • Neovascularization of the iris (NVI)
  • Fluorescein angiography
  • Optical coherence tomography (OCT)
  • B Scan Ultrasonography

Postoperative management includes follow-up meetings with your doctors because of the complications mentioned above regarding the decrease or loss of vision. Furthermore, these are the other complications that may arise after the operation:

  • Progression of diabetic retinopathy: A postoperative complication that affects the blood vessels in the retina, causing hemorrhage in the eyes.
  • Posterior capsular opacification: Characterized by a formation of a cloudy area behind the lens implant due to scar tissues. This is the most common postoperative complication that decreases vision.
  • Macular edema: Another frequent cause of decreased vision due to the build-up of fluid in the center of the retina called macula.

Doctors and scientists are still researching the most effective treatment for these postoperative complications caused by the treatment of cataracts in diabetes mellitus patients. It would be ideal for them to pinpoint the exact connection between cataracts and diabetes mellitus. However, right now, this is the current situation.

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