---
title: "Positive vs Negative Dysphotopsia: Weird Shadows After Lens Implant"
description: "Dysphotopsia refers to unwanted visual phenomena experienced after cataract surgery that are unrelated to refractive error. Two distinct forms are recognised: positive dysphotopsia and negative dysphotopsia. Although both occur in pseudophakic eyes, they have different characteristics, different underlying mechanisms and…"
url: "https://bluefinvision.com/knowledge-base/topics/symptoms-signs/positive-vs-negative-dysphotopsia-weird-shadows-after-lens-implant/"
updated: "2026-03-19"
category: "Symptoms & Signs"
---

# Positive vs Negative Dysphotopsia: Weird Shadows After Lens Implant

Dysphotopsia refers to unwanted visual phenomena experienced after cataract surgery that are unrelated to refractive error. Two distinct forms are recognised: positive dysphotopsia and negative dysphotopsia. Although both occur in pseudophakic eyes, they have different characteristics, different underlying mechanisms and different clinical trajectories.

Positive dysphotopsia describes the perception of light-based phenomena, halos, starbursts, arcs or streaks of light, typically experienced in low-illumination conditions or when looking at point light sources. It is most commonly associated with multifocal lens designs and usually diminishes with neuroadaptation over several months. ¹

Negative dysphotopsia is less well understood and more distressing. Patients describe a dark arc or shadow in the temporal visual field, often characterised as a curtain or crescent at the edge of vision. It occurs predominantly with square-edge monofocal lens designs and is thought to result from light distribution patterns at the lens edge interacting with the capsular bag. ² Unlike positive dysphotopsia, it does not always resolve spontaneously and can persist for months or, in some cases, indefinitely. ³

Management of persistent negative dysphotopsia ranges from reassurance and observation to, in refractory cases, lens exchange for a design with different edge characteristics. Most cases improve without intervention. ¹

**References**

1. Masket S, Fram NR, Cho A, Park SC. Pseudophakic dysphotopsia: review of causes and management. Journal of Cataract and Refractive Surgery. 2011;37(3):557–567.

2. Holladay JT, Zhao H, Reisin CR. Negative dysphotopsia: the enigmatic arc. Journal of Cataract and Refractive Surgery. 2012;38(7):1251–1265.

3. Henderson BA, Geneva II. Negative dysphotopsia: a perfect storm. Journal of Cataract and Refractive Surgery. 2015;41(10):2291–2312.

**Related Topics**:

- [Assessing Suboptimal Vision After Cataract Surgery: Why It Happens, and When We Enhance](https://bluefinvision.com/blog/assessing-suboptimal-vision-after-cataract-surgery-why-it-happens-and-when-we-enhance/)
- [Why Do I Still Need Glasses After Cataract Surgery?](https://bluefinvision.com/knowledge-base/topics/recovery-aftercare/why-do-i-still-need-glasses-after-cataract-surgery/)
- [Laser Enhancement After Cataract Surgery: When We Recommend It](https://bluefinvision.com/knowledge-base/topics/treatments-procedures/laser-enhancement-after-cataract-surgery-when-we-recommend-it/)
- [Piggyback Lens vs Laser: Fixing Small Errors After Cataract Surgery](https://bluefinvision.com/knowledge-base/topics/treatments-procedures/piggyback-lens-vs-laser-fixing-small-errors-after-cataract-surgery/)
- [Dry Eye After Cataract Surgery: Why Vision Seems Worse Than It Is](https://bluefinvision.com/knowledge-base/topics/conditions-diseases/dry-eye-after-cataract-surgery-why-vision-seems-worse-than-it-is/)
- [Blinking Clears My Vision After Cataract Surgery: Is It Dry Eye?](https://bluefinvision.com/knowledge-base/topics/symptoms-signs/blinking-clears-my-vision-after-cataract-surgery-is-it-dry-eye/)
- [How We Treat Ocular Surface Disease Before Considering Enhancement](https://bluefinvision.com/knowledge-base/topics/treatments-procedures/how-we-treat-ocular-surface-disease-before-considering-enhancement/)
- [Secondary Cataract (PCO): Cloudy Vision Months or Years After Surgery](https://bluefinvision.com/knowledge-base/topics/conditions-diseases/secondary-cataract-pco-cloudy-vision-months-or-years-after-surgery/)
- [What to Expect From YAG Laser Capsulotomy at Blue Fin Vision®](https://bluefinvision.com/knowledge-base/topics/treatments-procedures/what-to-expect-from-yag-laser-capsulotomy-at-blue-fin-vision/)
- [Cystoid Macular Oedema: Blurry Central Vision Weeks After Surgery](https://bluefinvision.com/knowledge-base/topics/conditions-diseases/cystoid-macular-oedema-blurry-central-vision-weeks-after-surgery/)
- [When Macular Disease Limits Vision After "Successful" Cataract Surgery](https://bluefinvision.com/knowledge-base/topics/conditions-diseases/when-macular-disease-limits-vision-after-successful-cataract-surgery/)
- [Toric Lens Rotation: When Post-Cataract Astigmatism Returns](https://bluefinvision.com/knowledge-base/topics/conditions-diseases/toric-lens-rotation-when-post-cataract-astigmatism-returns/)
- [Lens Tilt or Decentration: How Small Misalignments Affect Premium Lenses](https://bluefinvision.com/knowledge-base/topics/conditions-diseases/lens-tilt-or-decentration-how-small-misalignments-affect-premium-lenses/)
- [Halos and Glare After Cataract Surgery: Neuroadaptation Explained](https://bluefinvision.com/knowledge-base/topics/recovery-aftercare/halos-and-glare-after-cataract-surgery-neuroadaptation-explained/)
- [Positive vs Negative Dysphotopsia: Weird Shadows After Lens Implant](https://bluefinvision.com/knowledge-base/topics/symptoms-signs/positive-vs-negative-dysphotopsia-weird-shadows-after-lens-implant/)
- [Blur After Cataract Surgery: Our Step-by-Step Diagnostic Pathway Before Any Enhancement](https://bluefinvision.com/knowledge-base/topics/diagnostics-testing/blur-after-cataract-surgery-our-step-by-step-diagnostic-pathway-before-any-enhancement/)