With the number of high myopia cases continuing to climb, myopic macular degeneration (MMD) has become a major cause of visual impairment worldwide. Investigating how to combat this issue, a recent study published in Frontiers in Medicine suggests the cilioretinal artery may be a protective factor against MMD and VA loss in highly myopic eyes.

The cilioretinal artery has been previously reported as having a protective effect in fundus diseases. In central retinal artery occlusion, eyes with cilioretinal arteries may experience macular sparing and gain an intact central island field. The presence of a cilioretinal artery is also recognized as a protective factor in AMD. However, little is known about the effect of this vessel on MMD, the researchers noted.

The investigation included 1,692 highly myopic eyes of 1,692 patients, 245 of who had a cilioretinal artery. The cilioretinal arteries were further classified into four categories: “temporal cake-fork” (36%), “temporal ribbon” (53%), “multiple” (7%) and “nasal” (4%). The cilioretinal arteries were then placed into three groups depending on whether they had visible branches that reached the central foveal area.

The researchers found that eyes with cilioretinal arteries had significantly fewer cases of grade three or worse MMD and better VA. Another key finding: younger age, male sex, shorter axial length and the presence of a cilioretinal artery were associated with better VA in highly myopic eyes.

The “nasal” category included more eyes with grade three or worse MMD and worse VA than the other categories, while the “multiple” category had no eyes with grade of three or worse MMD. Additionally, the cilioretinal arteries that reached the central foveal area had less grade three or worse MMD and better VA.

Since the anatomical features of the fundus are complex in highly myopic eyes, the course of cilioretinal arteries can vary greatly, so a standard classification system is needed, the investigators suggested.