J Korean Ophthalmol Soc.  2021 Feb;62(2):261-265. 10.3341/jkos.2021.62.2.261.

Visual Field Ratio According to Distance in the Near Tangent Screen Test

• Na HM
• Yang HK
• Hwang JM

• KMID: 2512947
• DOI: http://doi.org/10.3341/jkos.2021.62.2.261

Abstract

Purpose
We evaluated the normative range of visual field ratio according to distance in the near tangent screen test performed in adults.
Methods
Adults above 18 years of age were prospectively recruited and underwent the near tangent screen test between February and August 2020. We developed a near tangent screen testing device, which was used at 10 and 20 cm distances from the screen. The tangent ratios (TRs), defined as the ratio of the visual field at the further distance to that at the closer distance, were analyzed according to the eight meridians, and the normative value of the TR in adults was deduced.
Results
The experiment was performed for 80 eyes of 40 adults. Their average age was 30.9 ± 7.0 years (range, 21-48). The mean TRs were 0.95 ± 0.10 and 0.97 ± 0.10 for the right and left eyes, respectively, so the visual field in either eye did not differ significantly according to distance. The average TR value for the eight meridians was 0.96 ± 0.10 (range, 0.73-1.23), and the TR did not show any significant difference among the eight meridians. The far and near visual fields did not intersect or overlap in any meridian, showing a TR value larger than 0.5.
Conclusions
Under the near tangent screen test, the visual fields in normal adults did not differ according to the test distance.

Keyword

Tangent screen test, Visual field