causes of blurry vision after cataract surgery

After cataract surgery, when your cataract is removed and a new artificial lens is placed inside your eye, you naturally expect clarity in your vision. Some people get to that point immediately, but for most it can take some time for vision to clear up. It might also be that you had great vision right after your surgery, but your sight starts to become blurry months or years after the procedure.

In this article we discuss the reasons for blurry vision after cataract surgery, whether it occurs days, weeks, months or years after the procedure and also discuss how you can get your vision cleared up again.




Most people have some degree of blurry vision right after surgery. This is usually due to swelling inside the eye that occurs as a normal healing response after surgery. Such blurring usually clears up over few days after surgery, as the eye heals. However, sometimes blurring may be from other causes, some benign and some more serious.

Below we discuss the various reasons why your vision might be blurred in the days right after cataract surgery and what can be done to improve your vision.



The commonest cause of blurred vision right after cataract surgery is swelling (edema) of the cornea, the clear part at the front of the eye. This swelling occurs from all the manipulation needed to remove the cataract and place a new lens in the eye.

Ultrasound energy, called ‘phaco’ is used inside the eye during the procedure, to break up and remove the cataract. This energy has the side effect of causing swelling in the eye. For harder or more dense cataracts, greater amount of ultrasound energy is needed to break up and remove the cataract, which in turn causes greater degree of corneal swelling.

The degree of swelling that occurs in your eye after surgery also depends on your own body’s response to the surgery and the surgical technique used. Some people will have more sensitive eyes, that will have a greater amount of swelling after surgery, even when the same surgical technique has been used. Additionally different surgical methods can be used to protect the cornea and prevent excessive swelling after surgery.


What can be done

Eye drops are prescribed to all patients after cataract surgery to reduce swelling in the eye. The type of eyedrops and number of times you will need to place it in the eye will depend on the results of your eye exam after the surgery. It is important that you use the eyedrops prescribed to you, as directed by your eye doctor.

The swelling of the cornea can take days or weeks to clear up completely, depending on the degree of swelling. For most people the swelling has cleared up completely, a month after surgery, which is the time eyedrops are also usually stopped.



If you have reasonably good vision after surgery but you feel like your vision is fluctuating and you need to blink or rub your eyes to clear up your vision, this may be because of dry eyes.

Dry eyes are very common after cataract surgery and occur due to a variety of causes. Symptoms include on-and-off blurring of vision, with or without a burning or sandy feeling in the eye. The symptoms may improve with the passage of time, as the eye heals after surgery, but usually remain to some extent, as dry eye also tends to worsen with age.


What can be done

Artificial tear eye drops are usually prescribed to combat dry eyes after cataract surgery. The best artificial tear eyedrops to use are the preservative free variety made by well reputed companies. Common over the counter artificial tear drops contain preservatives that may further irritate the eye and worsen dry eyes. Good quality artificial tears drops are safe to use, and can be used for as long as you have symptoms from dry eyes.



If you selected the kind of lens that would allow you to see well for both distance and near without the use of eyeglasses, you should know that adjusting to these lenses takes time. These lenses work by splitting incoming light so that it is focused at different distances inside the eye. This allows us to see images at different distances without the use of glasses.

However, because the incoming light is split at different focus points in the eye, there is some loss in the quality of vision, with a slight shadowing of images. Also, the brain needs to adapt to this different way of seeing images, and adjustment takes time.

Most people have adapted to the way images look with these lenses at about a year after their surgery.


What can be done

Adaptation to these lenses usually occurs with time. However, if the quality of your vision is bothering you too much, discuss it with your surgeon early on. If you decide on switching to a single focus lens, the surgery should ideally be done sooner, before the lens sticks firmly to the inside of your eye.



Rarely, you may be experiencing blurry vision after surgery due to severe inflammation or swelling in the eye, called toxic anterior segment syndrome (TASS). Blurring form this condition occurs 12-24 hours after surgery and your eye may also be painful. TASS is a severe reaction of your eye to the chemicals or medications used during surgery. Fortunately, it is rare and can be treated with anti-inflammatory eye drops.

If you experience a fall in your vision along with increasing redness or pain after surgery, you may have developed infection inside your eye (endophthalmitis). This is a serious condition and can result in permanent loss of vision if not treated in time. Infection developing inside the eye after cataract surgery is rare and patients are usually advised to report to their doctor immediately if they develop increasing pain, redness or worsening vision after surgery.


What can be done

Infection inside the eye is treated with antibiotic injections given in the eye, along with eyedrops, oral and injectable medications. Sometimes if the infection is severe, surgery (vitrectomy) may be done to reduce the load of infection from inside the eye.

Improvement in vision after infection developing inside the eye depends on early and proper treatment. However, full vision recovery is usually not possible due to the damage to the back of the eye (retina) caused by toxins or chemicals released by the infectious organisms.



If you develop a curtain like shadow in the side of your vision after cataract surgery , this may be a sign of retinal detachment. Retinal detachment is when the light detecting film at the back of your eye (the retina), peels off from the back of your eye (becomes detached). This results in loss of vision in the area of detachment. If left untreated, the loss of vision can spread to involve your whole vision, and can become permanent.

Retinal detachment may occur after cataract surgery from the forces created inside the eye during removal of the cataract and placement of the artificial lens. These movements and forces can cause pulling on the retina, which can result in the formation of a tear or break. Fluid already present in the eye, can enter this break and cause the retina to peel off from the back of the eye.

The chances of this occurring after surgery are greater if you have had a complicated surgery, or if you are very near sighted.


What can be done

If you experience a curtain like shadow in the sides of your vision after surgery, report it to your doctor immediately. You will likely need a surgery to repair the retina and the sooner this is done, the better the likelihood of recovering vision.



At times, surgery may not go as expected due to a variety of reasons including differences in the structure of the eyes and unexpected changes found inside the eye during surgery.

Some complications that may occur during surgery include: breaks in the membrane that that is supposed to hold the new lens, loss of fluid present in the back of the eye, incomplete removal of the cataract,  and loss of a piece of the cataract in the back of the eye.

In such cases there may be more than usual inflammation or swelling in the eye. This swelling causes blurring of vision.


What can be done

Depending on the exact nature of the complication, your surgeon might manage it with medications alone, or you may need another surgery.

Inflammation from a complicated surgery usually takes several weeks to settle.



After cataract surgery, your vision might be clear, but you may be seeing greyish threads, spots or rings in your vision. These are called floaters and occur due to shadows from particles inside the eye. These particles are present in the jelly like substance at the back of your eye, called the ‘vitreous’.

Cataract surgery does not involve surgery on the vitreous. This means that most of the floaters that you see after cataract surgery, were already present inside you eye and were not visible to you because of blurry vision from cataracts. As cataract surgery clears up vision, these pre-existing floaters become visible to the eye.

However, some floaters may be caused by cataract surgery itself. The manipulations that need to be done inside the eye during surgery, can indirectly cause movement inside the vitreous, that cause it to separate from the back of the eye (retina). The separation of the vitreous from the back of the eye, particularly the optic disc, causes the appearance of a large semi-circular or circular floater in the eye.

Floaters are usually the result of normal age-related changes inside the vitreous and do not cause any harm to the eye or to vision.

The large floater that appears after cataract surgery also commonly occurs in eyes of individuals who have not had cataract surgery, as a normal age-related change. It’s just that cataract surgery increases the chance of this floaters developing inside your eye.


What can be done

Floaters are harmless and do not cause any damage to the eye. They may break up or move out of your vision with time, but usually they are here to stay.

If they are bothering you too much, a laser procedure (YAG laser) or surgery (vitrectomy) can be performed to remove them. However, each of these procedures carries its own risks. The risks and benefits of having these procedures for the removal of floaters should be discussed with your eye doctor.




Blurry vision sometimes develops weeks after surgery. The commonest cause for this is swelling at the back of the eye (macular edema). Rarely it may be caused by late infection inside the eye. Below we discuss the details of macular edema occurring after cataract surgery.



If your vision was clear or was clearing up after surgery but then you suddenly develop blurry vision in your operated eye, you may have swelling at the back of your eye, called macular edema.

This swelling typically develops 6-10 weeks after surgery. It is commoner in those with diabetes, history of previous swelling in the eye, and in those who have had a complicated surgery.

Your doctor can see the swelling at the back of your eye during a dilated eye exam. A scan of the back of the eye called OCT (Optical Coherence Tomography) can also be done to measure the amount of edema and monitor changes in it over time.


What can be done

Macular edema after cataract surgery usually clears up a period of weeks with the use of special medicated eyedrops. For edema that does not settle, other treatments like oral medications, injection of medication into the eye or an eye surgery called vitrectomy may be needed.



Fall in your vision months to years after your surgery is usually either due to a condition called ‘posterior capsular opacification (PCO)’ or from another eye disease.

The presence of another eye disease can cause blurring of vision at any time after cataract surgery. However, it has been mentioned in this section because if your vision worsens months to years after cataract surgery, the only cataract surgery related cause is PCO. If it’s not that, then fall in vision is from another eye disease.



Posterior capsular opacification (PCO) is the commonest cause of blurring of vision months to years after cataract surgery. PCO is a layer of scar tissue that forms at the back of your new lens. It usually forms slowly, months to years after cataract surgery. However, it can also form earlier, particularly in younger individuals.

Posterior capsular opacification (PCO) is also called ‘after cataract’ as it usually gives symptoms similar to cataracts. It starts off with glare, halos around lights, poor vision in dim lighting, and double vision but progresses to cause increasing blurring of vision.


What can be done

PCO can easily be cleared up with a laser procedure called YAG capsulotomy. This is an in-office procedure that is quick, painless and efficient. Eyedrops are placed in the eye before the procedure which help to numb the eye and enlarge the pupil (colored part of the eye). You are then seated at the laser machine, with which the surgeon clears up the scar tissue behind your lens. The laser procedure takes only a few minutes and clarity in vision can be noticed immediately after the procedure.

Once you have had this procedure, you will never need it again, as the scar tissue does not return. Sometimes you may need another session if the PCO is too thick to be removed in one sitting or if the PCO was not cleared up far enough to completely move out of your vision.

YAG laser usually causes no side effect but sometimes it can cause swelling at the back of the eye (macular edema) and very rarely it can cause breaks in the retina, leading to a retinal detachment. Signs that you may have developed a break in your retina or a retinal detachment, include sudden increase in the number of floaters, flashes in your vision or a curtain like shadow in the side of your vision. If you develop any of these symptoms, report them to your eye doctor immediately.



Blurring of vision months to years after cataract surgery may be from another eye disease, unrelated to cataracts or cataract surgery.

For instance, if you are diabetic, the cause may be diabetic eye disease with swelling at the back of the eye or bleeding inside the eye from abnormal leaky vessels.

Macular degeneration is also a fairly common condition which develops with age, in which the central vision is affected.

Sometimes, blood vessels at the back of the eye can become blocked, especially in people with high blood pressure. This can result in swelling at the back of the eye, with sudden fall in vision.


What can be done

The chances of developing another eye disease is greater if you have any other medical conditions. Certain eye diseases also tend to arise as a result of aging. It is important to have your eyes examined at least yearly so any eye disease can be picked up early and treated timely.



Cataract surgery is a life changing procedure in which improves vision and quality of life in people with cataracts. However blurry vision can occur for different reasons at different stages after the surgery. Regular eye examinations are important to detect any problems and to manage them timely so clear vision can be restored.


Improve your vision.

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