Visual Field Test (Perimetry): What It Checks and How to Prepare
Quick answer: A visual field test (perimetry) maps how much you can see around you while looking straight ahead, one eye at a time. You press a button when you see small lights appear in different places. It is used to detect and monitor glaucoma, optic nerve disease, retinal conditions and brain problems such as stroke or pituitary tumours, which can cause loss of side vision you may not notice yourself.
Noticed this in your own eyes? Book an eye examination (NPR 400) with an optometrist at Vision Concern Lazimpat, Boudha-Tushal or Makalbari. WhatsApp +977 9841466716.
Related service: Comprehensive eye examination (NPR 400) at Vision Concern Lazimpat, Boudha-Tushal and Makalbari.
What happens during the test
You sit at a bowl-shaped machine with one eye covered and look at a central target. Small lights of different brightness flash in different places, and you press a button whenever you see one. It takes about 5 to 10 minutes per eye. Some lights are meant to be too dim to see, so missing lights is normal.
Who needs it
- People with suspected or diagnosed glaucoma
- Those with optic nerve conditions or unexplained vision loss
- After stroke or with pituitary problems
- Some medicines that can affect vision
- Driving or occupational vision assessments
Tips for a reliable result
Wear the right glasses or let the technician add a lens for near, rest well before the test, keep your eye on the central target and blink normally. Results improve with practice, so the first test is sometimes repeated.
When to get urgent care
Sudden loss of part of your vision, a curtain or shadow, or new blind areas need urgent same-day care rather than a routine field test.
How Vision Concern can help
Vision Concern optometrists in Kathmandu can examine your eyes, record what they find for comparison, update your glasses or contact lenses, and refer you to an ophthalmologist or eye hospital when medical treatment is needed. Vision Concern does not perform surgery or injections.
Frequently asked questions
Does a visual field test hurt?
No. It is painless and uses no drops in most cases.
How often should glaucoma patients have a field test?
Often every 6 to 12 months, as advised by the eye doctor managing the glaucoma.
Can I fail a visual field test by blinking?
Normal blinking is fine. Looking away from the centre affects accuracy, so keep your gaze fixed.
This guide is general information from the Vision Concern editorial team. It is not a diagnosis and does not replace an eye examination or medical advice.
Yes. Many visitors, particularly from Bangladesh and West Bengal (Kolkata), come to Nepal for cataract, retina, or other eye surgery at a hospital and also want new glasses, a general eye exam, or contact lenses at the same time, before or after their procedure. Vision Concern is an optical and eye-examination clinic, not a surgical hospital, so we work alongside hospitals such as Tilganga: we are happy to see you for glasses, contact lenses, or a routine check-up either side of your surgical treatment elsewhere.
No conversion is needed. Eyeglass prescriptions from Germany, France, the UK, the USA, China, Russia, and almost every other country use the same international format, SPH (sphere), CYL (cylinder), and AXIS, measured in diopters. Our opticians read this directly, so you can bring your prescription paper, a photo of it on your phone, or simply your current glasses, and we will use the same values. If your prescription is more than a year or two old, we recommend a quick, free re-check before we make your new pair.
Yes. Above roughly 3,000 metres, UV exposure increases sharply because of the thinner atmosphere and reflection off snow, and ordinary sunglasses (category 2-3) do not block enough UV to prevent snow blindness (photokeratitis). We recommend glacier glasses or category-4 sunglasses with side shields, and can fit these with your own prescription if needed. Vision Concern offers ZEISS polarized, UV400-certified sunglasses with prescription lenses, which we can prepare before you set off on your trek.