# What is Night Blindness?

Source page: https://www.kudretgozistanbul.com/en/blog/eye-diseases/what-is-night-blindness

**Author:** Kudret Eye İstanbul | **Medical Approval:** Op. Dr. Mehmet Ali Özdil | **Date:** 2026-09-13

> **Summary:** Night blindness is difficulty seeing in dim light: a symptom rather than a disease in itself, with several possible causes. One of the main ones is retinitis pigmentosa, a genetic condition in which the retina's rod cells are lost first; whether it can be treated depends on the cause.

## Quick Facts
- **Main causes:** retinitis pigmentosa (genetic), severe vitamin A deficiency, cataract, high myopia
- **Diagnosis:** visual field test and ERG
- **Treatable:** night blindness caused by vitamin A deficiency or cataract
- **Retinitis pigmentosa:** no definitive cure; an approved gene therapy exists only for the type caused by a mutation in the RPE65 gene

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## What is Night Blindness?
It appears when the retinal cells that perceive light and carry it to the optic nerve are damaged or deformed. In retinitis pigmentosa the rods (night vision) are lost first, then the cones (daylight vision); in the final stages sight is lost.
- Inherited; marriage between relatives increases the risk, and it can pass from mother or father to a child.
- Age of onset varies and can be very young; depending on the genetic type, childhood or young adulthood.
- Some genetic subtypes are seen more often or more severely in men.
- The course varies and follows family history; some people develop serious sight loss at an advanced stage, others do not; complete blindness is rare.

## Causes
- Genetic retinal conditions such as retinitis pigmentosa
- Severe vitamin A deficiency
- Cataract
- High myopia

A specialist examination and the family history are essential for diagnosis.

## Symptoms
- Seeing less at night as the first sign, sometimes with no findings on examination
- Much longer than normal adaptation when moving from light to dark
- Marked narrowing of the visual field (like looking through binoculars), with the areas beside the centre dark or not seen
- Intense sensitivity to light
- At advanced stages, daylight vision also becomes harder; in the final stages central vision can be lost

## Diagnosis
- **Visual field test:** measures how well areas outside the central point are seen, using objects and light; no anaesthetic, painless.
- **ERG:** electrodes around the eye and on the face measure retinal function; extremely mild discomfort is possible. There are two types for different purposes.
- With a family history, the condition can be detected easily at early stages.

## Treatment
- **Vitamin A deficiency:** the deficiency is corrected.
- **Cataract:** removed with surgery.
- **Retinitis pigmentosa:** no definitive cure. Approved gene therapy only for the RPE65 mutation type; research into gene therapy, retinal implants and the bionic eye continues for the others.
- Secondary problems such as cataract and macular oedema can be treated, so regular check-ups matter.
- Avoid tobacco and alcohol; a balanced diet containing vitamin A and antioxidants is recommended; high-dose supplements only under a doctor's supervision.
- Alternative routes such as vascular surgery, acupuncture or herbal treatments have no effect, according to the page.

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## Frequently Asked Questions

**Q: Does night blindness always end in blindness?**
A: No, it does not advance the same way in everyone. Some people keep a limited ability to see for life.

**Q: Is there a treatment?**
A: It depends on the cause. Night blindness from vitamin A deficiency or cataract can be treated. Retinitis pigmentosa has no definitive cure; approved gene therapy exists only for the RPE65 mutation type.

**Q: At what age does night blindness begin?**
A: It varies with the genetic type: in childhood for some, in young adulthood for others.

**Q: Does diet affect the course?**
A: A balanced diet with vitamin A and antioxidants is recommended, but it is not a definitive treatment.

**Q: Can someone with night blindness drive?**
A: Yes, if vision is sufficient during daylight hours; driving in the dark and at night is not recommended.