Validity and Reliability of 2 Cirrus Optical Coherence Tomography Procedures for Measuring Objective Ocular Torsion

Area of Science:

• Ophthalmology
• Medical Imaging
• Strabismus Research

Background:

• Torsional eye position, quantified by the disc-fovea angle (DFA), is a crucial objective parameter in diagnosing and managing vertical strabismus.
• Optical coherence tomography (OCT) offers a promising alternative to traditional fundus photography for DFA measurement.
• Existing OCT methods require further validation for clinical application in objective cycloposition assessment.

Purpose of the Study:

• To analyze the validity and reliability of two novel Cirrus high-definition OCT (HD-OCT) methods for measuring objective cycloposition.
• To compare the performance of Cirrus HD-OCT methods against Spectralis spectral-domain OCT and fundus photography (gold standard).
• To identify OCT methods offering clinical advantages in speed and simplicity for DFA measurement.

Main Methods:

• A prospective study involving 59 normal individuals, measuring DFA using fundus photography, Spectralis OCT (FoDi software), Cirrus HD-OCT (1-line scan), and Cirrus HD-OCT (macular cube).
• Each method was applied three times per participant, with repositioning between captures to ensure reliability.
• Manual quantification by two independent observers was performed for fundus photography and Cirrus cube methods.

Main Results:

• All three Cirrus HD-OCT methods demonstrated excellent agreement with fundus photography (Intraclass Correlation Coefficient [ICC] 0.83-0.84) with no significant mean value differences.
• Excellent reliability was observed across all tested methods (ICC 0.91-0.92), with minimal detectable change below 3° and absolute differences of 1° between repeated measurements.
• Inter-rater reliability was excellent for manual quantification methods (ICC 0.98 for cube, 0.94 for fundus).

Conclusions:

• Cirrus HD-OCT methods provide a valid and reliable alternative for assessing cycloposition via DFA measurement in normal patients.
• The Cirrus OCT HD 1-line scan method emerged as the most clinically advantageous due to its straightforward and rapid measurement process.
• The simplicity and speed of the Cirrus OCT HD 1-line scan eliminate the need for image export, enhancing clinical workflow efficiency.