About Cataracts

Cataract surgery is a common and safe procedure to remove a cloudy lens (cataract) and replace it with an artificial intraocular lens (IOL). This leaflet provides information about the surgery, recovery, and the different lens options available, including monofocal, multifocal, extended depth of focus (EDOF), and monovision lenses.

What is a Cataract?

A cataract is the clouding of the eye’s natural lens, leading to blurred vision, glare sensitivity, and difficulty with daily tasks. Cataracts typically develop due to aging but can also result from injury, medical conditions, or medications.

What Happens During Cataract Surgery?

Cataract surgery is an outpatient procedure performed under local anesthesia. The surgeon removes the cloudy lens and replaces it with an artificial intraocular lens (IOL). The procedure usually takes about 15–30 minutes per eye, with a recovery period of a few weeks.

Types of Intraocular Lenses (IOLs)

1. Monofocal Lenses

   • Provide clear vision at a single distance (near, intermediate, or far).

   • Glasses will still be needed for certain activities.

2. Multifocal Lenses

   • Designed to provide clear vision at multiple distances (near, intermediate, and far).

   • May reduce dependence on glasses but can cause glare or halos around lights.

3. Extended Depth of Focus (EDOF) Lenses

   • Provide an extended range of vision, improving intermediate and distance vision.

   • Less likely to cause glare and halos than multifocal lenses.

   • Reading glasses may still be needed for fine print.

4. Monovision (Blended Vision)

   • One eye is corrected for distance vision and the other for near vision.

   • The brain adapts to using each eye for different tasks.

   • Works well for some but may cause depth perception issues.

5. Toric Lenses

   • Used to reduce astigmatism

   • Astigmatism is a common refractive error caused by an irregularly shaped cornea or lens. Instead of being perfectly round, the cornea or lens has an uneven curvature, causing light to focus at multiple points on the retina rather than a single focal point. This leads to blurred or distorted vision at all distances.

   • Toric intraocular lenses (IOLs) are specifically designed to correct astigmatism during cataract surgery. Unlike standard spherical IOLs, toric lenses have different powers in different meridians of the lens to counteract the irregular curvature of the cornea.

   • Toric lenses must be positioned at a precise angle to correct astigmatism properly. If the lens rotates after surgery, it can reduce the effectiveness of astigmatism correction. Studies suggest that about 5-10% of toric lenses rotate (≥10 degrees) in the immediate post-operative period which can leave more astigmatism than desired. Toric lenses can be adjusted soon after surgery or glasses could be worn to correct any residual astigmatism. 

Choosing the Right Lens for You

The best lens option depends on your lifestyle, vision needs, and preferences. Discuss your daily activities, such as reading, driving, or using digital screens, with your ophthalmologist to determine the most suitable IOL.

Recovery and Aftercare

• Most patients experience improved vision within a few days.

• Some mild discomfort or irritation is normal and usually subsides within a week.

• Avoid heavy lifting and strenuous activities for at least a week.

• Use prescribed eye drops as directed to prevent infection and reduce inflammation.

• Attend follow-up appointments to monitor healing and vision improvements.

Possible Risks and Complications

While cataract surgery is generally safe, potential risks include:

• Posterior Capsule Rupture (PCR): A tear in the lens capsule during surgery. The National Ophthalmology Database (NOD) reports a PCR rate of approximately 0.79%. 

• Infection (Endophthalmitis): A serious but rare infection inside the eye. The estimated UK rate is 0.02%. 

• Loss of Vision: Severe vision loss is rare, with a risk of approximately 0.48% according to NOD data. 

• Cystoid macular oedema (CMO): This is a condition where fluid accumulates in the macula (the central part of the retina), causing blurred or distorted vision. It is one of the most common complications following cataract surgery, though it is generally treatable. According to the UK National Ophthalmology Database (NOD), the rate of clinically significant CMO after uncomplicated cataract surgery is around 1-2%. The risk is higher (3-5%) in patients with predisposing conditions such as diabetes, uveitis, or retinal vein occlusion. Most cases resolve with a 6-8 week course of anti-inflammatory drops, but severe cases may require steroid injections or other treatments.

• Posterior capsule opacification (PCO): This is a common condition that can develop after cataract surgery, causing blurred vision similar to a cataract. It occurs when residual lens epithelial cells grow on the posterior capsule (the thin membrane that holds the artificial intraocular lens in place), leading to cloudiness. PCO affects approximately 20-30% of patients within 2-5 years after cataract surgery. The risk is higher in younger patients, diabetics, and those with certain types of intraocular lenses (IOLs). PCO is not a new cataract but can be easily treated with a quick, painless laser procedure called YAG laser capsulotomy. This takes only a few minutes and is performed in an outpatient clinic. The laser creates a small opening in the cloudy capsule to restore clear vision. Most patients experience immediate improvement in vision.

Conclusion

Cataract surgery is a highly effective way to restore vision and improve quality of life. Understanding your lens options helps ensure the best visual outcome. If you have any questions or concerns, book an appointment with Dr Tatham to make an informed decision.