Transient Blindness in Metformin-associated Lactic Acidosis: Resolution With Supportive Care

Metformin remains the first-line pharmacologic treatment for type 2 diabetes mellitus due to its well-established efficacy and safety profile. However, a rare but serious complication is metformin-associated lactic acidosis (MALA), which carries a mortality rate of up to 36.2% in hospitalized patients. Those with chronic kidney disease and cardiovascular comorbidities are particularly vulnerable to severe outcomes. Among the rare manifestations of MALA is complete bilateral blindness, which typically requires urgent hemodialysis for reversal. Here, we present a case of MALA-induced blindness that was unexpectedly reversed through supportive medical management alone, prior to hemodialysis. This case underscores the critical role of early recognition and intervention by intensive care physicians in optimizing MALA outcomes. Further studies are warranted to elucidate the effects of MALA on the visual pathways, particularly the susceptibility of retinal cells and photoreceptors to metformin toxicities.