1. Blurry Vision: In normal, healthy eyes with good vision, blurry vision indicates a need for prescription lens that adds additional power or corrects astigmatism that distorts the natural optics of the eye. Unfortunately, blurred vision after refractive surgery may not be correctable, and can coexist with ghosting, smeared vision, or other visual abberations.

2. Smeared Vision: 'Smeared' or 'streaked' vision is another perceptual phenomena reported by laser eye surgery patients. Although 'smear' may seem to a less than technical term, many patients find that it nevertheless provides the best description of what they see. Some patients report their vision is smeared in two or more directions in a single eye. Like ghosts, smears vary in their transparency, with some being darker than others.

3. Ghosting: The term 'ghosting' was coined around 1957, and originally referred to the false image on a TV screen, caused by signal reflection. The perceptual effects of LASIK are often similar, but here, signal reflection results from irregularities in the corneal surface. Ghosts vary in terms of transparency, size, and colors ghosted. We have worked with patients with ten or more ghosts in low light conditions.

4. Glare: The term 'glare' is sometimes used to refer to any visual aberration resulting from refractive surgery. In the author's opinion, this usage is archaic, and reflects a lack of understanding of the perceptual phenomena that afflict those with complications. Here, the term is restricted to situations in which light seems to overflow, or 'seep outside,' its normal boundaries around light sources, or sources of reflected light, such as shiny objects.

5. Halos: Halos are another phenomena reported by laser eye surgery patients, particularly at night. Halos are usually seen as huge globes of illuminated fog surrounding sources of light. Sometimes the globes seem to contain other globes, brighter and denser, nested two or more levels deep. From a simulation perspective, starbusts and halos exist on a continuum, with starbursts shading into halos as the rays become less distinct and diffuse into each other.

6. Loss of Contrast Sensitivity: Contrast sensitivity is something that individuals with normal vision take for granted. When contrast sensitivity is lost, the ability to distinguish between variations of hue and brightness is lost. Perceptually, this effect is similar to turning down the Contrast adjustment on your television of monitor: Eventually sharp boundaries are lost. Objects merge together, as if a haze of grey soup had been poured over one's visual field.

7. Starbursts: Many laser eye surgery patients see rays or fine filaments coming off lights, even during normal daytime lighting conditions. At night, these rays can become dramatically longer and denser, something referred to as 'starbursting.' Starbursts are highly variable between patients, differing in terms of their size and shape, length of rays, the density of rays, and transparency (whether the light source is visible through the starburst).