When I strain my peripheral vision to look to the right, there's a dark shadow.

When straining the peripheral vision to look to the right, the appearance of a dark shadow may be caused by physiological factors, but it could also result from pathological conditions such as uveitis or vitreous opacities. Treatment should target the underlying cause.

I. Physiological Factors

Eye fatigue due to prolonged eye strain or age-related decline in eye function may lead to this symptom. These are typically normal physiological changes that do not require specific treatment; however, close monitoring of symptom progression is recommended.

II. Pathological Factors

1. Uveitis

Inflammation of the uveal layer—caused by pathogen infection or associated with rheumatic diseases and autoimmune disorders—can lead to uveitis. It is recommended to use medications such as indomethacin eye drops, pranoprofen eye drops, or diclofenac sodium eye drops under medical supervision. These drugs help suppress or eliminate pathogens and alleviate symptoms.

2. Vitreous Opacity

Vitreous degeneration or vitreous hemorrhage may lead to vitreous body lesions. Depending on the specific condition, treatments such as vitrectomy or laser vitreolysis may be performed under a physician's care.

In addition, other conditions such as retinal detachment due to retinal holes may also cause similar symptoms. Prompt medical evaluation and active treatment under professional guidance are necessary.