Positive vs Negative Dysphotopsia After Cataract Surgery
Last updated: October 2026
Short answer: dysphotopsias are unwanted optical images after cataract surgery. Positive dysphotopsia means bright artefacts such as streaks, arcs and starbursts. Negative dysphotopsia is a dark, crescent-shaped shadow in the temporal field. Negative dysphotopsia is reported by about 15% of patients on the first day, but only about 3% still notice it after a year.
Positive vs negative dysphotopsia
| Positive dysphotopsia | Negative dysphotopsia | |
|---|---|---|
| Symptoms | Light streaks, arcs, flashes, haloes, starbursts, especially at night | Dark temporal crescent or shadow, often noticed in bright light |
| Proposed causes | Light reflecting from a square-edged optic, high refractive index acrylic materials, small optics with a large pupil | Interaction between the IOL edge, the anterior capsule and the pupil; a gap ("penumbra") in light reaching the nasal retina |
| Course | Often improves with neuroadaptation | About 15% early, about 3% persistent at 1 year (Osher) |
Managing positive dysphotopsia
- Reassure and allow time for neuroadaptation.
- Correct any residual refractive error and treat dry eye.
- A drop that makes the pupil smaller (for example, brimonidine) may help night-time symptoms.
- In persistent, disabling cases, consider IOL exchange to a lens with a rounded edge or lower refractive index.
Managing negative dysphotopsia
- Wait first: most cases improve over weeks to months.
- Reverse optic capture: placing the optic in front of the anterior capsule while the haptics stay in the bag.
- Sulcus piggyback IOL: a secondary lens in the sulcus has relieved symptoms in many reported cases.
- Nd:YAG nasal anterior capsulectomy: removing the nasal edge of the anterior capsule overlying the IOL has been reported to help.
- IOL exchange to the sulcus in selected eyes.
- For the fellow eye in a symptomatic patient, some surgeons use reverse optic capture or a different IOL design from the start.
Frequently asked questions
What is the temporal shadow after cataract surgery?
It is usually negative dysphotopsia: a dark crescent in the temporal field caused by how light interacts with the IOL edge, the capsule and the pupil. Most cases improve with time.
Does negative dysphotopsia go away?
In most patients, yes. About 15% notice it on the first day, but only about 3% still have it after a year.
Does Nd:YAG capsulotomy help negative dysphotopsia?
A posterior capsulotomy does not usually help. A Nd:YAG nasal anterior capsulectomy over the IOL edge has been reported to relieve symptoms in some patients.
Related: angle kappa and multifocal IOLs, YAG laser capsulotomy and phaco step by step.
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