NCT07257341

Pilot Study of Normative Range of Field of Binocular Single Vision in Adults in Singapore

• Status: Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 30 (estimated)
• Sponsor: Tan Tock Seng Hospital · Academic / Other
• Sex: All
• Age: 21 Years – 59 Years
• Healthy volunteers: Accepted

Summary

The assessment and monitoring of the field of binocular single vision remains a crucial aspect of ophthalmological care, yet current clinical practice relies on normative standards established by Feibel \& Roper-Hall in 1974 that present significant limitations for contemporary application. The original study, conducted with a demographically homogeneous Caucasian population in St Louis using only "several" normal individuals, raises concerns regarding its applicability to Asian populations, particularly in Singapore, where ethnic and genetic factors may influence ocular characteristics. The limited sample size significantly increases the likelihood of Type II errors, whilst the temporal gap of over five decades introduces additional concerns regarding population changes, environmental factors, and advances in measurement techniques that have not been incorporated into current normative data. Given these substantial limitations in demographic representation, statistical power, and temporal relevance, there exists a pressing need to establish population-specific normative data for the field of binocular single vision in Singapore's adult population, which would provide more clinically relevant reference values and potentially improve diagnostic accuracy for ocular conditions in the local context.

Detailed description

The assessment and monitoring of the field of binocular single vision is a crucial aspect of ophthalmological care, particularly in the management of oculoplastics and strabismus. Currently, clinicians worldwide, including those in Singapore, rely on the normal boundary of the field of binocular single vision established by Doctor Robert M. Feibel \& Gill Roper-Hall in 1974 as the gold-standard parameter for clinical assessment. However, this long-standing standard raises several significant concerns regarding its applicability to our current population. The original study by Feibel \& Roper-Hall was conducted in St Louis, Missouri, United States of America, with participants who were likely of Caucasian descent. This demographic composition presents a potential limitation when applying these standards to Asian populations, particularly in Singapore, where ethnic and genetic factors may influence ocular characteristics. Furthermore, the study's methodology involved only "several" normal individuals, suggesting a sample size of more than two but fewer than ten participants. A sample size of this limited scope significantly increases the likelihood of Type II errors, potentially compromising the statistical power and reliability of the established normative values. The temporal gap of over five decades since the original study adds another layer of concern. Population characteristics, environmental factors, and lifestyle patterns have undergone substantial changes during this period, potentially affecting ocular health parameters. Additionally, advances in measurement techniques and an understanding of ocular physiology suggest the need for updated normative data that reflect current population characteristics and incorporate modern assessment methodologies. Given these limitations, there is a pressing need to establish population-specific normative data for the field of binocular single vision in Singapore's adult population. This would not only provide more relevant reference values for clinical assessment but also potentially improve the accuracy of diagnosis and monitoring of various ocular conditions in our local context.

Conditions

• Binocular Visual Function

Interventions

Type	Name	Description
DIAGNOSTIC_TEST	Field of Binocular Single Vision	The intervention involves a single field of binocular single vision assessment using the Takagi MT-325UD Projection Perimeter. Participants undergo binocular testing where they fixate and follow a single round light stimulus as it moves throughout the perimeter bowl. When participants perceive two distinct light stimuli (indicating loss of binocular single vision), they press a buzzer. The orthoptist records these responses and plots the boundaries on a standardised recording sheet to map the participant's field of binocular single vision. This intervention addresses significant limitations of the current gold standard established by Feibel \& Roper-Hall (1974). The original study was conducted with "several" normal individuals (likely fewer than 10 participants) of Caucasian descent in St Louis, Missouri, creating potential issues with statistical power and population applicability. Our study uses a larger, more robust sample size of 32 participants specifically from Singapore's Asian

Timeline

• Start date: 2025-10-15
• Primary completion: 2026-06-30
• Completion: 2026-10-14
• First posted: 2025-12-02
• Last updated: 2026-01-09

Locations

1 site across 1 country: Singapore