Manual Versus Instrumental Rotation of the Fetal Head in Malposition at Birth (ROTATE Study): Protocol for a Randomized Controlled Trial.

Diabetes mellitus represents one of the most significant global health challenges, with its prevalence continuing to rise at an alarming rate []. Among its microvascular complications, diabetic retinopathy (DR) remains a leading cause of visual impairment and blindness in the working-age population worldwide [,]. Traditionally, the clinical evaluation and staging of DR have relied heavily on structural retinal changes identified through fundus examination and imaging techniques [,,]. However, these approaches may fail to capture early functional deficits that precede overt anatomical alterations []. Visual acuity, although widely used in both clinical practice and research, primarily reflects high-contrast visual performance and does not adequately represent the complexities of everyday vision [,,,]. Contrast sensitivity (CS), defined as the ability to detect subtle differences in luminance between an object and its background, provides a more comprehensive assessment of visual function [,,]. Activities such as night driving, face recognition, and navigation in low-contrast environments depend heavily on intact CS, making it a critical yet often overlooked component of visual performance [,,]. New evidence suggests that functional impairments in CS may occur in diabetic patients even in the absence of clinically detectable DR [,]. This has caused a paradigm shift in the understanding of DR, from a solely microvascular disorder to a complicated neurovascular disease involving early retinal neuronal dysfunction [,]. Experimental and clinical studies have demonstrated that diabetes-induced metabolic stress, oxidative damage, and low-grade inflammation contribute to retinal neurodegeneration, affecting ganglion cells and inner retinal layers [,,]. These early alterations may disrupt visual processing pathways [,], resulting in measurable deficits in CS before the appearance of classical fundoscopic signs [].