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Should I have both of my cataract surgeries on the same day?

Your cataract surgeon may ask you to consider having both eyes taken care of in the same surgical session, on the same day. This is called Immediate Sequential Bilateral Cataract Surgery, or ISBCS. With ISBCS, the patient and doctor agree that both eyes will probably be taken care of in the same surgical session. The decision isn’t actually made until after the first eye surgery is finished. It goes like this: The surgeon operates on the first eye. If all goes well, then the patient is immediately prepped for the second eye.


Cataract surgery has historically been performed with a waiting time between the two eyes. The main reason was to allow the first eye to recover completely, and to make sure that nothing unexpected came up after the first surgery before proceeding to the second eye.

Today, surgeons often wait two to six weeks before the second eye cataract surgery is done. The inconvenience of doing so is obvious. What do you do between the first and second eye? How long do you have to wait to get new glasses? How much time do your loved ones have to take off to be with you during two surgeries and all the postoperative appointments? How many plane trips do your children have to take to be with you?

Wouldn’t it be better just to get it all done in one session?

What are the advantages of ISBCS?

The main advantage is that your overall surgical experience is much simpler. You only have one trip to the operating room. You finish the whole surgical and postoperative process more quickly with less postoperative visits. It is more convenient for you and for anyone who is helping you. You get back to your life quickly.

Clear shields can be used to protect the eyes, so you might be up taking care of your daily needs on the same day as your surgery and very likely on the next day. Your vision might not be perfect, but pretty good is enough to get by for the first day or two while the eyes recover. If you need glasses, you can get them within a couple of weeks.

Contrast this with waiting anywhere from two to six weeks between the two eyes. You have more postoperative visits. You take eyedrops for a longer time. You might need your kids or other loved ones to transport you to your appointments or help out otherwise. Your final glasses prescription is delayed.

Seems like a no brainer, right?

Not so fast. It might be a good idea. Then again, it might not.

With ISBCS you are taking a calculated risk. We take risks all day long. We risk our lives every time we get into a car to go to a public place, and every time we get onto an airplane. These risks are low, to the point that we may stop thinking about it. But risk is a fact of life and if we are agreeing to take a risk, it is best to be aware of what that risk is and why we want to do it.

Nine reasons not to choose ISBCS:

There are certain things that you know before your cataract surgery that help you predict your likelihood of having issues after surgery. Nine conditions that increase your risk of issues after surgery are listed below. If even one of these issues applies to you, you may want to consider delaying your surgery in your second eye until you know the first eye has recovered smoothly.

1. History of any type of corneal surgery, including LASIK: Unexpected refractive outcomes are much more common after cataract surgery in patients who have had LASIK and PRK. Eyes that have had refractive surgery also take longer, sometimes many weeks longer, to settle into their final refractive result.

2. Diabetic Retinopathy: Diabetic retinopathy increases your risk of issues after cataract surgery, even if you have no symptoms. Macular edema (blurring of the vision due to swelling in the retina) is much more common in patients with a history of diabetic retinopathy. This can require additional therapy and may never resolve completely.

3. Corneal pathology: The most common corneal issue is Fuch’s Endothelial Corneal Dystrophy. You can read more about Fuch’s here. Fuch’s makes you more prone to corneal edema after cataract surgery, which blurs your vision. Fuch’s can be mild, moderate or severe. The milder it is, the less likely it is to affect your cataract surgical outcome. Fuch’s can delay your postoperative visual recovery and can even require further surgical intervention to get an optimal visual result. Fuch’s is a bilateral condition, meaning it occurs in both eyes.

4. Macular degeneration: Macular degeneration increases your chances of macular edema after cataract surgery, especially if it is ‘wet’ macular degeneration. Also, in the setting of macular degeneration, it is important to have a clear discussion with your surgeon regarding your anticipated surgical outcome. You may want to make sure the first eye meets your expectations before proceeding with the second eye.

5. Advanced Age: If you are over 75-80 years old, you may recover more slowly after your cataract surgery. There are two reasons for this. First, our tissues recover more slowly from any stress as we get older. Second, the lens is denser the older you get. More energy is required to break the cataract up and remove it. This increases the possibility of corneal edema and macular edema.

6. High preoperative refractive error (thick glasses): The more nearsighted, farsighted, or astigmatic you are, the less accurately your surgeon can predict your postoperative refractive outcome. In patients with high refractive error, many surgeons value using the refractive outcome in the first eye to refine lens power choices in the second eye.

7. Glaucoma: If you have glaucoma, you are more likely to experience high pressure after cataract surgery. This usually resolves on its own, but can blur the vision in the mean time. You may need to use additional medications to lower pressure.

8. Dry Eye: Many people have mild dry eye. But if your doctor has told you that you have moderate or severe dry eye, cataract surgery can make this worse. Your vision may be blurred for a longer time postoperatively, and you are more likely to get a corneal abrasion (scratched cornea) after surgery.

9. Technically demanding cataract: Some cataracts are more difficult to remove than others. This can often be predicted before surgery. Difficult cataracts increase the risk of corneal edema and macular edema, and the final refractive outcome is less predictable.

There is one other issue that applies equally to everyone. Very (very) rarely, a complication called TASS (Toxic Anterior Segment Syndrome) occurs out of the blue. TASS is an acute, non infectious severe inflammatory condition that causes significantly blurred vision and requires aggressive treatment, sometimes even further surgery. Cases at a surgery center can occur in clusters. This means that there is a tiny risk that both of your eyes could be affected at the same time.

Reasons to consider ISBCS:

There are several good reasons to consider ISBCS.

Logistics: If you live in a rural area, you may need to go a long distance, possibly even hundreds of miles, to have your cataract surgery. In cases like this, you may consider the advantages of getting both eyes taken care of at the same time. You can then get yourself a hotel room and plan to stay in the area for a few days surrounding your cataract surgery.

Family support: Even if you don't live in a rural area, you may be dependent on others. Your cataract surgery will require that someone be available to take you to your surgery and postoperative appointments, and help out for a few days postoperatively. This may cause significant hardship for others. One of your family members or friends may need to travel a great distance or take time off of work to help you.

Final thoughts

There is one additional caution that applies to every person considering ISBCS- even if none of the above nine concerns applies. It has to do with precision.

Just like throwing a dart or hitting a putt, the exact refractive result of your cataract surgery can be estimated and is generally pretty accurate. But results do vary. The only way to get the most optimal combined refractive result is to separate the timing of the two eyes for long enough that the exact refraction and visual outcome in the first eye is known before making your final refractive and lens decisions for the second eye. This can take anywhere from two to six weeks or even more. Just as importantly, your subjective experience of your outcome in the first eye can affect choices you make for the second eye. You may, for example, have chosen an extended depth of focus lens or multifocal lens for your first eye. You may want to know how this goes before finalizing your decisions for the second eye.

There can be good reasons to consider ISBCS. But keep in mind that if you have ISBCS, you give up the opportunity to experience the results in the first eye before making your final decisions for the second eye.

Seattle based surgeon Christopher A. Kuntz MD has performed over 10,000 cataract surgical cases over the last 25 years. He is the principal author of, an international free website that helps patients make their best decisions before, during and after their cataract surgery.


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