Often there are times when additional testing is necessary to diagnose and manage certain eye problems. Southern Illinois Eyecare offers the most advanced diagnostic testing including visual field analysis, pachymetry, retinal photography, corneal topography and optical coherence tomography (OCT). OCT provides high resolution, non-invasive cross-sectional images of the tissues of the eye. It can best be compared to ultrasound but uses light rather than sound. This achieves clearer and sharper resolution that can detect microscopic early changes that would have previously been undetected until much later stages of the disease. This new technology benefits patients with glaucoma, retinal and macular disease as well as those considering corneal or refractive surgery.