What is the most likely diagnosis for sudden loss of vision characterized by seeing a 'bunch of lights'?

The sudden loss of vision accompanied by the perception of "seeing a bunch of lights" strongly indicates retinal detachment. This condition often presents with symptoms such as flashing lights, floaters, or a curtain-like shadow over the visual field, as the retina, which is essential for vision, becomes separated from its underlying supportive tissue. The experience of seeing lights is due to the stimulation of photoreceptors as the retina is pulled or disturbed, which aligns with the symptom described.

In contrast, other conditions may present differently. Glaucoma typically causes a gradual loss of peripheral vision and does not usually present with "bunches of lights." Macular degeneration affects central vision and is characterized by distortion or loss of central vision rather than abrupt loss or visual disturbances like flashes. Optic neuritis often involves a loss of vision but is usually accompanied by pain, particularly with eye movement, and does not typically include the visual disturbances described in this scenario.