The visual field refers to the area that the eye can perceive while focusing on a single fixed point without moving. The sharpest vision lies at the centre of the visual field, where objects appear most clearly. As objects move farther from the centre, they become increasingly blurred and eventually disappear.

Let delve deeper into the significance of visual field test in this article with Hoan My Gold Ky Dong Medical Center.

What is the visual field?

The clearest vision is concentrated at the centre of the visual field, while objects located further away become less distinct. As an object moves far enough to the side, it disappears entirely from the field of view.

Visual field assessments evaluate the condition of the retina, the visual pathways, and the visual centres. They also help assess the functionality of the retinal rods and the optic nerve pathways to the brain’s visual cortex.

What is a colour visual field? The peripheral retina in normal individuals cannot differentiate colors. Progressing from the periphery towards the centre, the first colour perceived is white, followed by blue, yellow, red, and finally green. Consequently, the green light stimulus test has the narrowest field, while the white light test produces the widest field.

Visual field test instruction

Colour visual field test enables experts to study retinal sensitivity more precisely. In clinical practice, colour tests are used to detect early central vision deficits. For example, central scotomas may not be apparent with white light tests but can be detected with colour tests.

Normal visual field limits

1. Monocular field of vision

Temporal: 100° to 110°
Nasal: 60°
Superior: 50° – 60°
Inferior: 70°
These limits can vary depending on the size, intensity, and colour of the test stimuli.

2. Binocular field of vision

Horizontal axis: 200°, vertical axis: 130°
The binocular field represents the area observed when both eyes are open simultaneously. It includes a shared visual field where objects are seen by both eyes. Clinically, individual visual fields of each eye are typically analysed.

When is Visual Field Test Needed?

Visual field testing can reveal early signs of conditions such as glaucoma, a progressive disease that damages vision. Many glaucoma patients are unaware of vision loss until tested. Visual field testing often identifies peripheral vision loss before symptoms are noticeable.

Glaucoma is a dangerous disease affecting both eyes, potentially leading to blindness if undiagnosed or untreated. Diagnosing glaucoma requires evaluating three key factors:

• Intraocular pressure (IOP)
• Optic nerve head condition
• Visual field defects

Specific visual field damage is one of the three critical indicators of glaucoma. In addition to aiding diagnosis, this test helps monitor progression and tailor treatment strategies.

Visual field testing also allows doctors to examine the optic nerve system, which includes the retina, optic nerve, and brain. Any issue along this pathway can alter the visual field. Repeated visual field tests at regular intervals help determine whether a patient’s vision is improving or deteriorating.

Doctors may recommend visual field tests for various reasons, including:

• Retinal pigment epithelium lesions
• Optic disc damage
• Optic neuropathy

Additional diagnoses supported by visual field testing include:

• Glaucoma, macular degeneration, and optic glioma
• Brain tumours and multiple sclerosis
• Temporal arteritis
• Central nervous system disorders
• Pituitary gland abnormalities
• Hypertension or stroke
• Long-term use of certain medications (e.g., Plaquenil or hydroxychloroquine)
• Thyroid-related eye disease
• Central nervous system pathologies affecting the visual pathways.

Doctors may sometimes request patients to repeat the visual field test to ensure accurate results. For instance, if a patient is fatigued, the test outcomes may not fully reflect their actual condition.

Visual field testing at Hoan My Gold Ky Dong Medical Center

Patients may be scheduled for follow-up appointments after several weeks, months, or even a year to ensure no new issues have arisen. Visual field testing is a particularly critical step in the management of glaucoma. Once a patient is diagnosed with glaucoma, regular visual field assessments are necessary to monitor the effectiveness of the ongoing treatment regimen.

Visual field-testing methods

1. Estimation method

This technique involves comparing the patient’s visual field to that of the examiner.

2. Dynamic perimetry

This is a method of measurement in which a target stimulus is moved from a non-visible area into a visible area until it becomes detectable. Dynamic perimetry plays a significant role in determining the outer boundaries of the visual field. By adjusting the size and intensity of the light stimulus, dynamic perimetry can also identify central scotomas.

However, shallow scotomas or those with relatively flat borders, particularly in the nasal field, are often overlooked during dynamic perimetry examinations. While dynamic perimetry effectively outlines the edges of deep scotomas, it does not provide information on the extent of deep damage within the scotoma.

3. Static perimetry

This method uses stationary stimuli presented at different locations. By adjusting stimulus intensity and repeating presentations, the threshold can be determined. Known for its precision, static perimetry is invaluable in detecting and quantifying early central retinal damage, often the initial site of many eye conditions. While it has limitations in assessing peripheral damage comprehensively, static perimetry remains a critical tool in vision care.

At Hoan My Gold Ky Dong, we pride ourselves on being the only facility within the Hoan My Medical Group offering comprehensive eye care services. Leveraging state-of-the-art technology and expertise, our visual field-testing service plays a vital role in diagnosing and treating ocular diseases.

Ensure your eyes receive the best care.
Contact us today via our hotline at 0919 209 039 or register online here.

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HOAN MY GOLD KY DONG MEDICAL CENTER
Customer Care Hotline: 0919 209 039
Address: 27 Ky Dong Street, Ward 9, District 3, Ho Chi Minh City
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