Clinical Ophthalmology (Dec 2024)
Redefined Formula for Anterior Chamber Volume Calculation: Quantitative Analysis of Biometric Parameters Across Ocular Pathologies
Abstract
Arturs Zemitis,1,2 Vincenzo Rizzuto,1– 4 Diana Lavrinovica,1,2 Juris Vanags,1,2 Guna Laganovska1,2 1Riga Stradins University, Department of Ophthalmology, Riga, Latvia; 2Pauls Stradins Clinical University Hospital, Clinic of Ophthalmology, Riga, Latvia; 3School of Advanced Studies, Centre for Neuroscience, University of Camerino, Camerina, Italy; 4Latvian American Eye Centre, Riga, LatviaCorrespondence: Arturs Zemitis, Department of Ophthalmology, Riga Stradins University, Dzirciema 16, LV-1007, Riga, Vidzeme, Latvia, Email [email protected]: 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.Plain Language Summary: Our study examines the differences in measuring aqueous humor volume in the eye using two devices, the Heidelberg Anterion and the Zeiss IOLMaster 700. Aqueous humor is the clear fluid in the front part of the eye, which circulates at a rate of 1.0% to 1.5% per minute. We refined a formula to calculate the volume of this fluid using the Zeiss IOLMaster 700, based on specific eye measurements. We found that the volume measurements from both devices were very similar, showing a strong agreement. The study also discovered that eyes with pseudoexfoliation syndrome (PEXS), a condition affecting the eye, had significantly lower fluid volume compared to eyes without the condition. This was also true for other eye measurements like anterior chamber depth (ACD) and axial length (AL). These findings are important because they show that simpler and more accessible methods for measuring fluid volume in the eye can be used effectively, especially in developing countries where advanced equipment may not be available. The study highlights the changes in eye measurements with age and how the new formula aligns well with existing methods. Overall, eyes with PEX show reduced measurements in various eye parameters.Keywords: anterior chamber volume, pseudoexfoliation, IOL power calculation, Heidelberg Anterion, performance measures
