Visual Field Testing in Ranchi
Comprehensive perimetry (visual field testing) for glaucoma, neurological vision disorders, and optic nerve conditions — performed and interpreted by Dr. Dibya Prabha at Neurovision Clinic.
What is Visual Field Testing (Perimetry)?
Visual field testing, also called perimetry, is a systematic method of measuring the entire scope of a person's vision — both central detail vision and peripheral (side) awareness. The test maps the sensitivity of vision across the visual field, detecting areas of reduced or lost vision (scotomas) that the patient may not be consciously aware of.
At Neurovision Clinic, Dr. Dibya Prabha uses automated perimetry to evaluate and monitor a range of conditions:
- Diagnose and monitor glaucoma — peripheral vision loss is often the first sign
- Assess optic nerve damage from neurological conditions including optic neuritis and ischemic optic neuropathy
- Evaluate vision loss after stroke affecting visual pathways in the brain
- Monitor for hydroxychloroquine (Plaquenil) retinal toxicity in rheumatology patients
- Evaluate unexplained vision loss — differentiate retinal from neurological causes
Why is Visual Field Testing (Perimetry) Done?
- •Diagnose and monitor glaucoma — detect peripheral vision loss before the patient notices it
- •Evaluate optic nerve disorders including optic neuritis, ischemic optic neuropathy, and papilledema
- •Assess vision loss after stroke or brain injury affecting visual pathways in the brain
- •Monitor for hydroxychloroquine (Plaquenil) retinal toxicity in rheumatology patients
- •Evaluate unexplained vision loss — differentiate retinal from neurological causes
- •Document visual function for disability assessment or medico-legal purposes
- •Monitor pituitary tumors and other brain lesions compressing the visual pathways
How Visual Field Testing (Perimetry) is Performed
- 1
Setup
You sit comfortably at the perimeter machine. One eye is patched. Your chin and forehead are positioned against supports. The room lighting is standardized.
- 2
Instructions
The technician explains the procedure: keep looking at the central orange fixation light at all times. Small white lights will flash at various locations and brightness levels throughout your visual field.
- Press the button each time you see a light — even if it's very dim
- It's normal to miss some lights — the machine is testing your threshold
- Don't look around for lights — keep your eyes fixed on the central target
- 3
Testing
The automated program presents lights at various locations in your visual field. You respond to each light you see. The machine adjusts light intensity to determine the threshold of visibility at each point. A typical test takes 5–10 minutes per eye.
- 4
Analysis
The machine generates detailed maps and statistical analyses including mean deviation, pattern standard deviation, and glaucoma hemifield test. Dr. Dibya Prabha reviews the results, compares them to any previous tests, and integrates the findings with your complete eye examination and OCT results.
How to Prepare
- •No special preparation is needed — you can eat, drink, and take medications normally
- •Bring your current glasses — you'll wear them during the test if needed (near correction for the central target)
- •Get a good night's sleep — fatigue affects concentration and test reliability
- •The test requires concentration — if you're not feeling well, consider rescheduling
- •A practice test may be run first to familiarize you with the process
Related Conditions
Visual Field Testing (Perimetry) helps diagnose and monitor these conditions. Explore our condition pages for more detailed information about each.
Frequently Asked Questions
What is a visual field test?
A visual field test (perimetry) measures your entire scope of vision — both central and peripheral (side) vision. It maps areas of vision loss (scotomas) that you may not have noticed. It is essential for diagnosing and monitoring glaucoma, neurological conditions affecting vision, and certain retinal diseases.
How is a visual field test performed?
You sit at the perimeter machine and look at a central fixation point. Small lights of varying brightness appear in different areas of your peripheral vision. You press a button each time you see a light. The machine maps which areas you can and cannot see, creating a detailed map of your visual field.
How long does visual field testing take?
A standard visual field test takes about 5–10 minutes per eye. More detailed or specialized testing may take 15 minutes per eye. It requires concentration and cooperation — the technician will guide you through the process.