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

NCT07257341 | Recruiting

• 1 other identifier: 2025-1293
• Study Type: observational
• Target: 30
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Binocular Visual Function

Keywords

Binocular field of vision

Outcome Measures

Primary Outcomes (1)

• Field of Binocular Single Vision in Asian population

  Establish comprehensive normative range of field of binocular single vision (BSV) specifically for healthy adults in Singapore's population aged 21-59, creating locally relevant reference standards that reflect ethnic, genetic, and contemporary population. BSV is the ability to use both eyes simultaneously and coordinate the slightly different images from each eye into a single, unified, three-dimensional mental percept. The "field of binocular single vision" is the specific area within the overall visual field where this fusion and single vision can be maintained. To measure the field of BSV using Goldmann perimetry, a moving light stimulus is presented while the patient uses both eyes. The test maps the area where the patient can maintain fusion (single vision). The boundary where fusion breaks (and diplopia starts) is plotted across different directions to define the BSV field.

  up to 20 minutes during 1 study visit.

Secondary Outcomes (1)

• Comparison of current field of binocular single vision gold standard between Caucasian population vs Asian population

  Up to 20 minutes during 1 study visit.

Interventions

Field of Binocular Single Vision DIAGNOSTIC_TEST

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

Eligibility Criteria

• Age: 21 Years - 59 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Healthy Individuals

You may qualify if:

• Age: 21 to 59 years old
• Gender: Males or females
• Ethnicity: Asian descent.
• Language comprehension: Able to understand verbal spoken instructions in:
• British/American English
• Mandarin Chinese
• Bahasa Melayu
• Protocol compliance: Ability to comply with the study protocol, as determined by the investigator's judgment
• Consent capacity: Must be able to understand and provide informed consent, with signed informed consent form required before any study assessments

You may not qualify if:

• \- Communication barrier: Unable to understand verbal spoken instructions
• Medical history:
• Any facial trauma
• Any ocular trauma
• Any head trauma
• Any history of ocular disease
• Any history of ocular surgery
• Systemic condition(s)
• Near visual acuity:
• o Right eye \& Left eye monocularly, binocularly unaided near vision: worse than N6 at 40cm from participant's nose
• Ocular alignment:
• o Prism cover test at near (30cm) of equal or greater than 10 prism diopters at these positions of gaze:
• Primary gaze
• Right gaze
• Left gaze

Sponsors & Collaborators

• Tan Tock Seng Hospital: lead

Study Sites (1)

Tan Tock Seng Hospital

Singapore, Singapore, 308433, Singapore

RECRUITING

Related Publications (2)

• Feibel RM, Roper-Hall G. Evaluation of the field of binocular single vision in incomitant strabismus. Am J Ophthalmol. 1974 Nov;78(5):800-5. doi: 10.1016/0002-9394(74)90303-1. No abstract available.

  PMID: 4425006 RESULT

• Kakizaki H, Umezawa N, Takahashi Y, Selva D. Binocular single vision field. Ophthalmology. 2009 Feb;116(2):364. doi: 10.1016/j.ophtha.2008.08.046. No abstract available.

  PMID: 19187829 RESULT

Study Officials

• Daniel Chin, MBBS

  Tan Tock Seng Hospital

  PRINCIPAL INVESTIGATOR

• Sebastian Yue, MSc

  Tan Tock Seng Hospital

  STUDY DIRECTOR

Central Study Contacts

Zheng Kuang Noel Soh, BSc

CONTACT

+65 6357 3693; zheng.kuang.soh@nhghealth.com.sg

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Consultant

Study Record Dates

• First Submitted: November 20, 2025
• First Posted: December 2, 2025
• Study Start: October 15, 2025
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): October 14, 2026
• Last Updated: January 9, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

SG (1)