Redefined Formula for Anterior Chamber Volume Calculation: Quantitative Analysis of Biometric Parameters Across Ocular Pathologies.

Purpose: This study evaluates the discrepancies between ACV measurements obtained from the Heidelberg Anterion and Zeiss IOLMaster 700 and investigates the significance of ACV and other ocular biometry parameters.

Patients and methods: To investigate intraocular fluid circulation, a robust formula was developed for ACV measurement using the Zeiss IOLMaster 700. A pilot study was conducted to validate this formula, which relied on WTW, CCT, and ACD. The formula used was ACV = (RAC)^2 × (CCD) × 1.51. ACV measurements showed a median of 155.38 (IQR = 131.15-180.06) for the Heidelberg Anterion and 144.11 mm³ (IQR = 125.62-159.81) for the Zeiss IOLMaster 700. The intraclass correlation coefficient (ICC) for ACV was 0.908, indicating excellent agreement between devices.

Results: Intraocular fluid volume was significantly lower in eyes with PEXS compared to those without. Eyes with PEX had an ACV of 133 ± 28.3 mm³ versus 142 ± 30.7 mm³ in non-PEX eyes, a statistically significant difference (t (196) = -2.09, p = 0.038, d = -0.301). Significant differences were also observed in ACD and AL between PEX and non-PEX eyes, with PEX eyes showing reduced measurements.

Conclusion: Our findings reveal that age-related changes in ACD and ACV are significant, with the redefined formula showing excellent agreement with AS-OCT methods. Eyes with PEX exhibit reduced ACD, ACV, and AL measurements. Additionally, an accessible method for ACV measurement, not relying on Pentacam or AS-OCT, would be valuable, particularly in developing countries, to facilitate broader clinical research.