Type 2 diabetes mellitus (DM) is a chronic metabolic disorder that is characterized by the body's inability to use insulin efficiently. This condition has significant consequences that extend beyond its well-documented impact on glucose regulation [1].

DM is associated with a wide range of eye illnesses affecting both the anterior and posterior segments of the eye. Some commonly studied disorders include diabetic retinopathy (DR), diabetic cataract, refractive error (RE), optic neuropathy, glaucoma, and ocular surface abnormalities [2].

The near vision reflex, also known as the near response or near triad, involves a coordinated set of ocular adjustments including accommodation, convergence, and pupillary constriction. This reflex is essential for maintaining clear and single vision when shifting focus from distant to near objects [3]. Accommodation typically decreases with age, resulting in presbyopia. Medical problems, such as diabetes, have been linked to an early decline in accommodation [4], [5].

Hyperglycemia can affect the ocular accommodating system, which is responsible for the eye's ability to focus and retain clear vision at different distances [6]. Studies conducted by Braun et al. [4] and Adnan et al. [7] indicate that diabetic individuals may experience a decline in their eyes’ ability to accommodate at an earlier stage compared to healthy individuals of the same age. These data suggest that the visual difficulties experienced in type 1 DM may be linked to the dysfunction of the eye's accommodating mechanism.

The vascular and neurological complications of type 2 DM can contribute to the deterioration of the accommodation reflex. Impaired retinal blood flow have been linked to changes in retinal vascular caliber and altered autoregulatory mechanisms [8]. Furthermore, the neuropathic effects of type 2 DM can impair the neural pathways responsible for the coordination of the accommodation reflex, further exacerbating the visual challenges faced by these patients [5].

Considering that previous studies evaluating accommodation function were performed in patients with type 1 DM and using subjective methods, we aimed to evaluate accommodation function in patients with type 2 DM without DR using objective methods. We conducted a study to assess accommodation and vergence amplitudes in patients diagnosed with type 2 DM and compared them to healthy individuals of similar age.