Visual Field Test (Perimetry)

Mapping Vision and Monitoring Sight-Threatening Diseases at Erdem Hospital

The Visual Field Test also known as Perimetry or the Computerized Visual Field Test is an essential, non-invasive diagnostic tool used to map the full extent of a person's vision, including both the central and peripheral (side) view. This sophisticated test measures the eye's sensitivity to light across its entire range of vision, helping to detect subtle areas of vision loss or "blind spots" (scotomas) that a patient may not yet be aware of.

At Erdem Hospital, this test is fundamental for the diagnosis, staging, and long-term follow-up of several sight-threatening eye and neurological conditions. We use advanced Automated Static Perimetry (like the Humphrey Visual Field Analyzer) to ensure reliable, accurate, and consistent measurements.

For international patients, regular and reliable Visual Field Testing is critical, particularly for monitoring chronic diseases. The quality and frequency of these diagnostic services in Turkey meet high international standards, forming the bedrock of effective disease management.

Critical Applications and Disease Monitoring

The Visual Field Test is crucial because it provides objective evidence of functional damage to the visual pathway, often when other structural tests (like OCT) or symptoms are still inconclusive.

Disease Category	Primary Application of Visual Field Test	Key Findings
Glaucoma (Eye Tension Disease)	Diagnosis and Monitoring: Glaucoma is characterized by peripheral vision loss. The test is vital for detecting specific, irreversible nerve damage patterns (e.g., arcuate scotoma) and tracking the rate of progression over time.	Peripheral vision loss, nasal step, arcuate scotomas.
Optic Nerve Diseases	Diagnosis and Follow-up: Used to detect damage to the optic nerve caused by inflammation (Optic Neuritis), lack of blood flow (Ischemic Optic Neuropathy), or trauma.	Central vision loss or enlarged blind spots.
Retina Diseases	Diagnosis and Follow-up: Used to map vision loss caused by conditions like Retinitis Pigmentosa (peripheral or "tunnel vision") and centrally affecting diseases like Age-Related Macular Degeneration (AMD) (central blind spots - often monitored by the simpler Amsler Grid).	Peripheral or central scotomas.
Neurological Diseases	Localization of Lesions: Damage to the visual pathways in the brain (e.g., from stroke, brain tumors, or Multiple Sclerosis) produces distinct, often symmetrical, visual field defects.	Homonymous Hemianopia (same side loss in both eyes) or Bitemporal Hemianopia (outer field loss).

The Perimetry Procedure

The Visual Field Test is simple, non-invasive, and does not require dilation of the pupils.

Preparation: The patient sits comfortably and places their chin and forehead on a support in front of a bowl-shaped instrument. Each eye is tested separately while the other eye is covered.
Testing: The patient is instructed to look steadily at a central target light for the duration of the test. Small, dim lights flash randomly in their peripheral and central vision.
Response: Whenever the patient sees a flash of light, they press a response button. The machine records the location and intensity of the lights the patient could not detect, creating a detailed sensitivity map.
Duration: The test is quick, typically lasting 10–20 minutes for both eyes, depending on the test strategy used (e.g., SITA-Standard, SITA-Fast).

Reliability and Interpretation

The test is highly reliant on the patient's attention. Modern computerized perimeters incorporate reliability indices (such as fixation losses) to ensure the patient maintained focus, validating the test results. The ophthalmologist interprets the resulting map (often compared to age-matched normal data) to determine the type and severity of vision loss.

What's Included in the Diagnostic Journey

The Visual Field Test is a standard tool included in chronic disease monitoring packages:

VIP airport-hotel-hospital transfers so you're never navigating on your own.
A three-night stay in premium accommodation.
Comprehensive Eye Examination including the Visual Field Test (Perimetry).
Full Consultation where the specialist explains the test findings and its implications for treatment.
One year follow-up support.
English-speaking staff and interpreters so nothing gets lost in translation.

Frequently Asked Questions (FAQ)

Is the Visual Field Test painful? No, the test is entirely painless and non-invasive. It only requires attention and cooperation.
Why is it so important for Glaucoma? Glaucoma causes progressive, silent vision loss. Regular Visual Field Tests are the only functional way to prove that the nerve damage is progressing and that the current treatment (drops/surgery) needs adjustment.
Can I drive after the test? Yes. Unlike dilation for a retinal exam, the Visual Field Test does not require pupil dilation, so you can drive immediately after the test.
What are 'Skotomas'? They are areas of reduced or absent vision (blind spots) identified on the Visual Field map.
How often should the test be repeated? For high-risk or recently diagnosed Glaucoma patients, the test may be repeated every 3–6 months to establish a stable baseline and track progression.
What is the Amsler Grid? A simpler, square-patterned card used specifically to monitor central vision at home, often recommended for Macular Degeneration patients.

Restoring Confidence Through Precise Monitoring

The Visual Field Test provides critical, objective evidence that guides sight-saving treatment decisions. At Erdem Hospital, we rely on this precise diagnostic tool to monitor the function of your visual system. With 37 years of experience in patient care, our specialists ensure your treatment is adjusted exactly when needed, protecting your sight against chronic disease. Our goal is for you to feel looked after, supported, and confident in the vigilance of your eye care.