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

NCT ID: NCT07257341

Last Updated: 2026-01-09

Basic Information

• Recruitment Status: RECRUITING
• Total Enrollment: 30 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2025-10-15
• Study Completion Date: 2026-10-14

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.

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

Study Design

• Observational Model Type: COHORT
• Study Time Perspective: CROSS_SECTIONAL

Interventions

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

Intervention Type: DIAGNOSTIC_TEST

Eligibility Criteria

Inclusion Criteria

• 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

Exclusion Criteria

• 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
• Up gaze
• Down gaze
• Extraocular movement:

o Extraocular movement of over-action or under-action of equal or greater than 0.5 in any of the nine cardinal positions of gaze

• Confrontational Visual field:

o Abnormal monocular visual field on confrontational visual field test

• Hess chart test o Abnormal or asymmetry in pattern of extraocular muscle action in Hess chart test

• Minimum Eligible Age: 21 Years
• Maximum Eligible Age: 59 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Tan Tock Seng Hospital

OTHER

Sponsor Role: lead

Responsible Party

Daniel Chin Yuxiang

Associate Consultant

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Daniel Chin, MBBS

Role: PRINCIPAL_INVESTIGATOR

Tan Tock Seng Hospital

Sebastian Yue, MSc

Role: STUDY_DIRECTOR

Tan Tock Seng Hospital

Locations

Tan Tock Seng Hospital

Singapore, Singapore, Singapore

Site Status: RECRUITING

Countries

Singapore

Central Contacts

Zheng Kuang Noel Soh, BSc

Role: CONTACT

zheng.kuang.soh@nhghealth.com.sg

+65 6357 3693

Facility Contacts

Zheng Kuang Noel Soh, BSc

Role: primary

zheng.kuang.soh@nhghealth.com.sg

+65 6357 3693

References

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.

Reference Type: RESULT

PMID: 4425006 (View on PubMed)

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.

Reference Type: RESULT

PMID: 19187829 (View on PubMed)

Provided Documents

Document Type: Study Protocol

View Document

Other Identifiers

2025-1293

Identifier Type: -

Identifier Source: org_study_id