Brief Answer:
It could be a problem in your retina

Detailed Answer:
Hello thanks for your question . Seeing some thing black in the eye is a symptom of vitreous degeneration dear which means the gel in the eye in undergoing changes . Almost all the time it is benign and has no dangers but sometimes it can cause a retinal hole to form which needs a laser treatment. I would advise you therefore to get a dilated retinal examination and dilated retinoscopy . In these tests drops are instilled in the eye so that pupil dilates and we can see the retina and also check for any hidden refractive errors and if there are any errors we can correct them accordingly .
I would be happy to help you if you have any further queries .

Hope my answer helps you get well soon .

Regards

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