This indicates an alteration to the macula, which is a central part of the retina and allows us to see fine details, read, recognise faces or drive. The main cause for this is the wet type of age-related macular degeneration (AMD) in the elderly, or another type of inflammation of the retinal layers in younger people (such as a neovascular macular membrane in patients with high myopia).

Accompanied at times with seeing “lights or flashes”- the pupil needs to be dilated to properly assess the entire retina. Most of the time this is caused by a posterior detachment of the vitreous (PVD), the gel that fills the back of the eye and that is in close contact with the retina. PVD is a degenerative process associated with ageing, however it is advisable to rule out a retinal tear (which requires prophylactic laser treatment to prevent it progressing to retinal detachment), haemorrhages, or an already established retinal detachment.

The main causes are retinal detachment or an alteration in the nerve pathways that send information from the eye to the brain.

It is advisable to rule out lesions in the cornea (such as corneal erosion, a foreign body), infections (bacterial keratitis, especially in contact lens wearers), anterior uveitis (inflammation of the middle layer of the eye, responsible for ocular irrigation) or acute increases in intraocular pressure.

Eye trauma can cause damage to almost any part of the eye, from the most anterior and external parts (penetrating trauma to the cornea and sclera), to the most internal and posterior parts, such as the retina (tears or detachment of the retina or vitreous haemorrhages) or the optic nerve (traumatic optic neuropathy or optic nerve avulsion).

Sudden double vision is a cause of urgency, especially if it is accompanied by pain or drooping of the eyelid, since within the possible causes are diseases that can be dangerous.