Applied Conversion Equation for Optical Coherence Tomography

The investigator wants to investigate how big the differences are between measurements of the back of the eye taken by different OCT machines. The study is called: Applied Conversion Equation for Optical Coherence Tomography (ACE-OCT) study.

Inclusion Criteria: * Patients aged 18 years or above * Patients with a diagnosis of Type 1 or Type 2 Diabetes Mellitus * Patients with a known diagnosis of DMO in at least one eye * Patients being seen in DMO clinics, Digital Surveillance Clinic or Virtual Diabetic Retinopathy clinics Exclusion Criteria: * Patients under 18 years old * People unwilling or unable to give informed consent * Patients in whom it is not possible to take OCT scans, for instance those with: * Dense cataracts * Corneal Scarring * Severe physical disabilities preventing them from adequate positioning. * People with other ocular pathologies known to impact retinal thickness, including: * Age related Macular Degeneration (AMD) * Branch or central retinal vein occlusion (BRVO/CRVO) * Macular Hole * Glaucoma * High Myopia with a spherical equivalent \> -5.00 diopters * Epiretinal membrane * Eyes with at least one scan containing segmentation errors * Eyes with at least one scan that is ungradable