Título / Title

AXIAL LENGTH TO ESTIMATE THE VOLUME OF VITRECTOMIZED SPACE (ALVIS): DEVELOPMENT OF A FORMULA FOR INDIVIDUALIZED DOSAGE OF INTRAVITREAL THERAPIES

Introdução / Purpose

To derive a formula to estimate the volume of the vitrectomized space (VVS) in eyes with axial length (AL) between 20 and 32 mm.

Material e Método / Methods

This analytical, observational, cross-sectional study included individuals who underwent vitrectomy between 2013 and 2023. The sample of 144 individuals was randomly selected and stratified for AL, for sex, and for history of cataract surgery. Before surgery, AL was measured using optical biometrics. A complete vitrectomy was performed, followed by a complete fluid/air exchange, and finally a balanced saline solution was injected. The volume infused was recorded.

Resultados / Results

The median (IQR; range) VVS was 6.8 (2.2; 3.2–9.3) mL in men and 7.0 (2.6; 3.1–9.1) mL in women (p = 0.676). The median VVS was 6.8 (2.6; 3.1–9.2) mL in the phakics and 7.05(2.4; 3.3–9.3) mL in the pseudophakics (p = 0.329). A positive Pearson correlation coefficient (r = 0.952; p < 0.001) was found between AL and VVS in this sample. The coefficient of determination in the cubic polynomial regression (R2) was 0.946. Similar results were observed in both sexes, both in phakic and in pseudophakic patients. The estimated cubic polynomial regression equation for this sample was VVS = 0.0014×AL3 − 0.1373×AL2 + 4.7633×AL –48.33.

Discussão e Conclusões / Conclusion

A formula (ALVIS – axiallength to estimate the volume of vitrectomizedspace) was developed to suggest the VVS according to the AL.

Palavras Chave

Vitreous body; Volume; Vitreoretinal surgery; Biometry

Area

SURGICAL RETINA

Institutions

Universidade Federal de Pernambuco - Recife - Pernambuco - Brasil

Authors

ANDREA ANDRADE AZEVEDO DE VASCONCELOS, VALESCA CASTRO NERI, JULIANA MOREIRA DE SANTANA, LUIZ FELIPE LYNCH DE MORAES, GABRIEL ROCHA LIRA, MARIA ISABEL LYNCH GAETE, RODRIGO PESSOA CAVALCANTI LIRA