Introduction
It is evident from the name that it is a macular disease, So first you should know what a macula is. The central part of the retina which provides central, sharp, clear, and color vision is called the macula.
This area contains special photoreceptor cells which are sensitive to light. These photoreceptor cells receive light and color signals to make you capable of seeing objects colorful and bright.
DISEASE
Diabetic Macular ischemia is a decrease in blood flow to the macula due to uncontrolled diabetes.
In diabetes, continuous uncontrolled blood glucose level affects the retinal microvessels thus causing either leakage or occlusion of capillaries and pre-capillary arterioles.
Leakage of retinal capillaries:
Retinal capillaries are lined by a single membrane of endothelium and overlying pericytes which are the supporting cells of capillaries and allow the selective matter to diffuse out of the blood.
Due to hyperglycemia, junctions of pericytes become weak due to which it becomes completely permeable and allows the vascular content to leak out thus causing microaneurysms, hard exudates and hemorrhages, and retinal edema.
Occlusion of Retinal capillaries:
Raised blood glucose level damages the capillary wall and causes their basement membrane to thicken. Due to their thickening, firstly microvessels become narrow and then get blocked completely.
This Occlusion does not allow the blood to reach the retina including the macula thus devoiding it of oxygen and nutrition and making the Macular region ischemic.
It is an associated Complication of diabetic retinopathy (DR) and vision loss caused by it is irreversible.
Diabetic Macular ischemia Diagnostic tests
The following test can be done to diagnose DMI
- OCTA (Optical Coherence Tomography Angiography)
This new technique is useful in visualizing the layers of retinal capillaries without injecting fluorescein sodium dye
- FA (Fluorescein Angiography)
Symptoms
Sudden decreased visual acuity.
Diabetic Macular ischemia MANAGEMENT
Until now, there is no defined treatment for DMI. But managing the risk factors like controlling blood glucose level and blood pressure can prevent developing DMI. Anti-VEGF and steroids have brought no significant improvement in treating DMI
One surgical procedure which can be a suitable treatment option for DMI is laser photocoagulation. It can slow down the disease process as well as improve vision but it has a strong association with multiple complications.
As this disease has no significant symptoms to notice, so you should regularly monitor your glucose level and blood pressure. As soon as you notice a regular rise in BP or hyperglycemia you should consult an eye doctor for a detailed fundus examination and continue follow-up visits from time to time to be on the safer side.
Risk factors
High blood glucose levels and high blood pressure are contributing risk factors for Diabetic Macular ischemia.
Would you have interest in taking retina images by smartphone?
Fundus photography is superior to fundus analysis as it enables intraocular pathologies to be photo-captured and encrypted information to be shared with colleagues and patients.
Recent technologies allow smartphone-based attachments and integrated lens adaptors to transform the smartphone into a portable fundus camera and Retinal imaging by smartphone.
RETINAL IMAGING BY YOUR SMARTPHONEREFERENCES
- Sim DA, Keane PA, Fung S, et al. Quantitative analysis of diabetic macular ischemia using optical coherence tomography. Investigative ophthalmology & visual science. 2014;55(1):417-423.
- Arend O, Wolf S, Jung F, et al. Retinal microcirculation in patients with diabetes mellitus: dynamic and morphological analysis of perifoveal capillary network. British Journal of Ophthalmology. 1991;75(9):514-518.
- Ashton N. Arteriolar involvement in diabetic retinopathy. The British journal of ophthalmology. 1953;37(5):282.
- Bresnick G, Engerman R, Davis M, et al. Patterns of ischemia in diabetic retinopathy. Transactions. Section on Ophthalmology. American Academy of Ophthalmology and Otolaryngology. 1976;81(4 Pt 1):OP694-OP709.
- Cogan DG, Toussaint D, Kuwabara T. Retinal vascular patterns: IV. Diabetic retinopathy. Archives of ophthalmology. 1961;66(3):366-378.
- Shepro D, Morel NM. Pericyte physiology. The FASEB Journal. 1993;7(11):1031-1038.
- Hammes H-P, Lin J, Renner O, et al. Pericytes and the pathogenesis of diabetic retinopathy. Diabetes. 2002;51(10):3107-3112.
