Ocular diabetes causes significant morbidity worldwide. Diabetic retinopathy (DR) is a well-known vascular disease and it may be the most frequent cause of visual loss in afflicted patients. Besides the retinal involvement, Diabetes Mellitus may affect the anterior ocular segment, especially the ocular surface. Altered corneal sensory nerves and neurotrophic defects are often found in these patients. Likewise, an associated dry eye can also be present. Cataracts are common in the diabetic population. The risk of diabetic macular edema following phacoemulsification surgery is increased. Intravitreal anti-VEGF and corticoids are frequently utilized to treat these diseases. However, these repetitive treatments have the potential of being toxic for the corneal endothelium.

Good glycemic control is essential to avoid the appearance of pathological alterations in the previously mentioned diseases. The ocular surface serves to help correct diagnosis and follow-up of diabetic patients. The measurement of glucose in the lacrimal film is a noninvasive test that can show blood glucose changes throughout the day without needing needle prick or blood tests.

Confocal microscopy can help to understand what happens in sensitive corneal receptors. Different methods to determine the glycemic levels in the tear film have been and are being investigated. The development of sensing contact lenses, which can monitor the glycemic level throughout the day, could be useful in the future. However, corneal sensitivity may be altered in patients with Diabetes Mellitus. The alterations may be related to systemic polyneuropathy present in Diabetes Mellitus or not. The alteration of corneal sensitivity can cause a dry eye due to the absence or decrease of the afferent reflex. Lacrimal osmolarity may be increased.

This special issue is focused on ocular diabetes on the ocular surface, and manuscripts reporting pathogenic, diagnostic, and therapeutic aspects of ocular diabetes on the ocular surface as well as established relationships with clinical manifestations are welcome.

Potential topics include but are not limited to the following:

• Motorization of glucose in the tear film by sensing contact lenses
• Effects of Diabetes Mellitus on the cornea
• The corneal endothelium in Diabetes Mellitus
• Corneal sensitivity alterations in Diabetes Mellitus
• Novel technologies in the diagnosis of ocular surface diabetic alterations
• Corneal Biomechanics alterations in Diabetes Mellitus
• Osmolarity on the ocular surface in diabetic patients
• Therapeutic modalities for ocular surface diabetic alterations
• Impact in visual function and visual assessment of ocular surface diabetes