Why Some Patients See Halos After Cataract Surgery

1. Neuroadaptation (Most Common Cause)

After cataract surgery, the brain needs time to adapt to the new intraocular lens (IOL).

• This adaptation period can last weeks to months
• Halos gradually reduce as the brain adjusts

This is normal and temporary in many patients.

2. Type of Intraocular Lens (IOL)

Certain advanced lenses can increase halos initially:

• Multifocal IOLs
• Trifocal IOLs
• Extended Depth of Focus (EDOF) lenses

These lenses split light to provide near and distance vision, which may cause:

• Halos
• Glare
• Reduced contrast at night (initially)

3. Pupil Size in Dim Light

Patients with large pupils at night are more likely to notice halos because:

• Light enters through peripheral zones of the lens
• Optical aberrations become more noticeable

4. Residual Refractive Error

If small power remains after surgery:

• Mild myopia
• Astigmatism It can cause blur and halo effects, especially at night.

5. Dry Eye After Surgery

Cataract surgery can temporarily worsen dry eye.

• Tear film instability causes light scattering
• Leads to glare and halos

This is very common and treatable.

6. Posterior Capsular Opacification (PCO)

Months or years after surgery, some patients develop:

• Clouding of the posterior capsule
• Causes glare, halos, and reduced clarity

PCO is easily treated with YAG laser capsulotomy.