Dynamic changes in axial length and refractive error following intraocular pressure normalization in acute primary angle-closure glaucoma.

PURPOSE: To investigate the dynamic changes in axial length (AL) and refractive error following the normalization of intraocular pressure (IOP) in acute primary angle-closure glaucoma (APACG).

METHODS

This study included thirty-one consecutive patients with APACG. AL and keratometric values were measured using IOLMaster before IOP normalization, after IOP normalization, and postoperatively. The analysis focused on IOP levels, AL, keratometric values, and the anticipated refractive discrepancy (the expected refractive error post-IOP normalization with intraocular lens power for emmetropia correction predetermined pre-IOP normalization).

RESULTS

After IOP normalization, AL decreased significantly from 22.7 to 22.4 mm and IOP from 57.5 to 16.5 mmHg (P < 0.001). The change in IOP was positively correlated with the change in AL (r = 0.451, P = 0.011), with a decrease of 0.05 mm in AL per 10-mmHg reduction in IOP (P = 0.011). Moreover, the alteration in IOP was associated with the predicted refractive difference (r = 0.431, P = 0.015) and a predicted refractive difference of + 0.26 diopter (D) per 10-mmHg decrease in IOP (P = 0.015).

CONCLUSIONS

Decreased IOP correlated with reduced AL and increased predicted refractive error (hyperopia). Therefore, lowering IOP before biometric assessment may improve refractive outcomes when feasible. In cases requiring immediate intervention, each 1-mmHg reduction in IOP decreases AL by 5 μm, yielding a hyperopic shift of 0.026 D.