Chronic kidney disease (CKD) is a condition characterized by the gradual loss of kidney function over time. As CKD progresses, it can lead to a number of complications, including changes in vision. Some people with CKD experience blurred vision as their kidney function declines. In this article, we’ll explore the link between CKD and vision problems, looking at the causes, symptoms, and treatments for CKD-related blurred vision.
What is chronic kidney disease?
Chronic kidney disease refers to the gradual loss of kidney function over a period of months to years. The kidneys act as filters to remove waste and excess fluid from the blood. They also help regulate levels of electrolytes like sodium and potassium, and produce hormones that regulate blood pressure and red blood cell production.
As kidney function declines, waste builds up in the blood. This condition is known as uremia. The loss of kidney function also leads to imbalances in fluid levels, electrolytes, and hormones. There are five stages of chronic kidney disease, based on a test called glomerular filtration rate (GFR). GFR measures how much blood the kidneys can filter per minute. The stages are:
- Stage 1 – GFR at 90 or above – Normal kidney function but urine tests or imaging shows kidney damage
- Stage 2 – GFR 60-89 – Mild loss of kidney function
- Stage 3 – GFR 30-59 – Moderate loss of function
- Stage 4 – GFR 15-29 – Severe loss of function
- Stage 5 – GFR below 15 – End-stage kidney failure requiring dialysis or transplant
The most common causes of CKD are diabetes and high blood pressure, which damage the small blood vessels in the kidneys. Other causes include glomerular diseases, genetic disorders, and blockages in the urinary tract. Risk factors for CKD include family history, older age, heart disease, and smoking. CKD sometimes has no symptoms until it has progressed to an advanced stage. When symptoms do appear, they can include:
– Fatigue
– Nausea
– Loss of appetite
– Difficulty concentrating
– Swelling in hands and feet
– Puffiness around eyes
– Muscle cramps
– Changes in urination
– Itchy skin
– Shortness of breath
As CKD progresses, serious complications can develop, including heart disease, bone disease, anemia, and neurological problems. Blurred vision is one complication that some people with CKD experience. Next, we’ll look at why CKD can affect vision.
How can CKD cause vision problems like blurred vision?
CKD can impact vision in a few different ways:
Fluid retention
One of the key jobs of the kidneys is to maintain fluid balance in the body. Healthy kidneys remove extra fluid from the blood through urination. As kidneys fail, they are less able to eliminate excess fluid. This leads to swelling and puffiness throughout the body, including around the eyes and in the retina. Having swollen eyes and retinas can distort images and make vision blurry.
High blood pressure
High blood pressure (also called hypertension) is both a cause and complication of CKD. Uncontrolled high blood pressure can damage the small blood vessels that supply oxygen and nutrients to the eyes. This can impair blood flow to the retina and optic nerve, leading to several vision problems.
Uremia
As kidney function declines, waste builds up in the blood. This condition, known as uremia, can also affect the eyes and vision. One way is that uremia leads to anemia, or low red blood cells. Anemia starves the retina of oxygen, which can damage retina cells. Uremia also causes toxic levels of waste in the blood to circulate to the retina and optic nerve, impairing their function.
Diabetic retinopathy
Diabetes is the leading cause of CKD. Over time, high blood sugar from uncontrolled diabetes can damage the blood vessels in the retina at the back of the eye. This diabetic retinopathy can cause progressive vision loss. People with CKD related to diabetic kidney disease have an increased risk of diabetic retinopathy.
Retinal detachment
Retinal detachment is when the retina pulls away from the back of the eye. Advanced CKD increases the risk of retinal detachment due to the changes in fluid balance. Warning signs of retinal detachment include sudden flashes of light, floaters, shadows or blind spots in vision. Retinal detachment is an ophthalmologic emergency requiring prompt treatment.
Symptoms of vision problems related to CKD
Many people in the early-middle stages of CKD have no noticeable vision problems. Vision changes tend to emerge in the later stages as kidney disease advances. Symptoms may include:
– Blurred vision – Objects look out of focus and edges appear fuzzy
– Distorted vision – Objects may look warped or different sizes
– Floaters – Small specks or clouds moving in the field of vision
– Flashing lights – Seeing flickering or flashing lights
– Blind/dark spots – Loss of vision in a section of the visual field
– Double vision – Seeing overlapping images, or double vision
– Eye pain or redness – Resulting from inflamed blood vessels in the retina
– Increased sensitivity to light – Being bothered by normal light due to retinal damage
– Poor night vision – Having trouble seeing in low light from retinal abnormalities
– Seeing halos – Seeing a halo or rainbow effect around light sources
Not everyone with CKD will experience visual symptoms. But sudden changes in vision or onset of new symptoms warrants an urgent eye exam to identify the cause.
Diagnosing vision problems related to CKD
If you have CKD and notice vision changes, see an ophthalmologist (eye doctor) right away for an exam. Be sure to tell them about your kidney disease. The eye exam will include a visual acuity test to check sharpness of vision, dilated eye exam to view the retina, and tonometry to test fluid eye pressure.
Additional tests may include:
– Slit lamp exam – Uses a slit lamp to view structures in the front of the eye. Can identify swelling, bleeding or damage.
– Optical coherence tomography (OCT) – Non-invasive imaging that creates cross-sections of the retina to detect abnormalities.
– Fluorescein angiography – Traces blood flow and vessel leakage in the retina by injecting fluorescent dye.
Based on the exam findings, the ophthalmologist can diagnose specific vision problems related to CKD. These may include diabetic retinopathy, macular edema, retinal detachment, glaucoma or cataracts. Identifying the cause is important for proper treatment.
Can vision problems from CKD be treated or corrected?
In many cases, vision impairment related to CKD can be treated to prevent further vision loss or even improve vision. Treatment options depend on the specific cause and may include:
Medications
Eye drops like beta-blockers and carbonic anhydrase inhibitors can reduce fluid buildup in the eye and decrease eye pressure for conditions like glaucoma. Steroid eye drops can treat inflammation related to diabetic retinopathy or macular edema.
Surgery
Procedures like retinal laser surgery, retina reattachment surgery and cataract removal surgery can improve vision impaired by CKD complications. Vitrectomy surgery removes scar tissue and blood from inside the eye.
Kidney dialysis
If blurry vision is caused by fluid retention and uremia, dialysis treatments to filter the blood can remove excess fluid and waste buildup. This may help clear vision.
Improving kidney function
Some types of kidney disease are reversible if caught early. Treating the underlying kidney condition with medications, lifestyle changes or sometimes surgery can improve kidney function enough to resolve associated vision problems.
However, damage from certain CKD-related eye conditions like diabetic retinopathy may be irreversible. But early detection and management are still important to prevent total vision loss. Regular eye exams are key for people with CKD.
Does treating CKD help prevent vision loss?
Yes, managing your chronic kidney disease is critical for preserving eye health and vision. Good CKD control can lower your risk of developing associated vision complications like diabetic retinopathy and macular edema. Recommended ways to protect your vision include:
– Taking medications to control diabetes and blood pressure – This prevents further kidney and eye damage.
– Quitting smoking – Smoking worsens kidney disease and diabetic retinopathy risk.
– Maintaining healthy blood sugar and cholesterol levels – Reduces progression of diabetic eye disease.
– Following your kidney diet and fluid intake limits – Prevents fluid retention that can impair vision.
– Doing regular dialysis treatments – Removes excess fluid and waste if kidneys can’t.
– Seeing your nephrologist regularly – To monitor kidney function.
– Getting eye exams yearly or more often if needed – Early detection of eye issues allows quicker treatment.
While CKD can negatively impact vision, proper management of kidney disease and eye problems provides the best chance of preserving remaining vision.
How are cataracts related to CKD?
Cataracts are a frequent complication of chronic kidney disease. A cataract is a clouding of the eye’s naturally clear lens that impairs vision. People with CKD tend to develop cataracts earlier and have faster progression than the general population.
There are several ways CKD contributes to cataract formation:
– Fluid retention – Swelling in the lens proteins can create clouding.
– Uremic toxicity – Waste buildup in the bloodstream also reaches the lens.
– Oxidative stress – Imbalance between free radicals and antioxidants in the lenses.
– Metabolic disorders – Diabetes, high blood sugar and abnormal mineral levels promote cataracts.
– Medications – Some drugs like corticosteroids used to treat kidney disorders increase cataract risk.
– Eye inflammation – Common with diabetic kidney disease and can lead to cataracts.
Cataracts usually develop slowly and cause blurry, cloudy or dim vision. Treatment is surgical removal of the old lens and replacement with an artificial intraocular lens to restore clearer eyesight.
The takeaway on CKD and vision problems
Chronic kidney disease impacts vision in some patients as it progresses to advanced stages. Common CKD-related vision disorders include diabetic retinopathy, glaucoma, macular edema and cataracts. Blurry vision and other vision changes can result from fluid retention, high blood pressure, uremia and diabetic eye disease affecting the retina and optic nerve.
Vision loss related to CKD may be irreversible but early detection and treatment can often prevent significant impairment. It’s critical for people with chronic kidney disease to get regular eye checkups. Controlling CKD through medication, diet, dialysis and treatment of underlying kidney disorders can also help prevent associated vision complications. While CKD can negatively impact eyesight, proper management provides the best odds of maintaining vision.
Conclusion
In summary, chronic kidney disease can contribute to blurred vision and other vision problems through several mechanisms. Fluid retention, high blood pressure, uremia, and diabetic retinopathy arising from CKD can affect the retina, optic nerve and other parts of the eye. Common symptoms include blurred vision, flashing lights, and eye pain or redness. However, many people with CKD don’t experience vision changes until advanced stages.
Diagnosing the specific vision disorder allows targeted treatment to preserve remaining vision. This may involve medications, surgery, dialysis or kidney function improvement. Controlling CKD through proper treatment is also critical to prevent vision loss. With regular eye exams and management of both CKD and related vision complications, many patients can maintain good eyesight. While CKD poses added risks, vision impairment is not inevitable. Being proactive greatly improves the chances of protecting vision.