If you are suffering from any of these problems (halos, stars, floaters, "ghosts", etc) - then you probably already know that a) these annoying buggers reveal themselves at night, especially while driving, and b) it seems like regardless of what you try, nothing can be done to stop them! So... what is the deal? Let's get into the myths and realities of what works and doesn't work.
1. Floaters
Floaters are caused when bits of cellular debris coagulate or break off from the interior walls of our eyes and start to drift about in the vitreous medium. In night driving conditions where there is a high contrast between light and dark, these buggers can catch the light and become visible and distracting.
The first thing to know about floaters is that usually they are benign and go away on their own. But the second thing to know is that sometimes they are NOT benign and might be caused by a serious problem like retinal detachment or vitreous detachment. These serious risk mainly affect people over the age of 50 and are extremely common in people over the age of 80. Diagnosis is performed with a dilated eye exam.
So, if you think you are having an issue with floaters then please make an appointment with your optometrist for an eye exam right away. And if you see flashes of light, please seek urgent care as there could be an immediate problem.
2. Stars
Stars are an optical "spreading out" from a point of light, that can be highly visible in the dark. You might see them everywhere: car headlights, taillights, and stop lights.
The most common configuration is a star with four points. But note the points are not necessarily evenly spread out. You could also just see two points. You may also see a collection of several points, but the points tend to cluster along one direction.
So, what is this caused by? The answer is: astigmatism.
I had excellent vision growing up and never needed glasses. It probably helped that I lived in a rural area and did not watch TV as a kid and spent a lot of time outside. However, in around my mid thirties I started to notice that it was a bit annoying to drive at night because of these sort of blurry "stars" around the lights. I got an eye exam and sure enough, we found a mild astigmatism in both eyes. Not enough to be a big problem during the day, but quality of vision usually degrades under night time conditions due to increased pupil dilation, which is why that is where I saw it first.
So, why does astigmatism do this? Astigmatism is a type of visual defocus that only occurs along a specific direction in your vision. We also refer to this direction as an "axis". In a normal non-astigmatic condition when the eyes are not focused, everything is blurry equally in all directions, and a point source (such as a light) would spread into a round fuzzy blob. But, in the case of astigmatism, it spreads out into a kind of fuzzy "football" that is elongated in one direction. In fact, the eye itself (or the lens) has the same kind of "football" curvature which is the source of the problem.
The four-pointed star comes into play when both eyes have an astigmatism and the axis is different along each eye. Then you will see a kind of superposition of two "football" blurs which is actually how your brand is merging two points of view into one. If you alternate closing one eye, then the other, you can appreciate which eye is causing which sets of points of the star.
Fortunately, one you have the correct prescription, correction of astigmatism with glasses is highly effective. It does take a bit of getting used to, so, if you have never worn glasses before try wearing the corrective glasses in various conditions for at least two weeks before attempting to drive with them on.
Bottom line: get an eye exam and get the right glasses!
3. Halos
Okay, so here we have some tough news. Halos are the worst. Unlike the nice fuzzy blur or fuzzy footballs created by ordinary refractive errors of the eye, halos are like a fuzzy "donut" or sometimes a fuzzy "whorl". The bad news is, ordinary glasses can't fix these at all. The underlying issue is called a wavefront refractive error and is a kind of irregularity in the surface of the eye and/or lens that cannot be corrected using a standard prescription.
Some people have reported good results using a wavefront corrected contact lens. But be ready for some serious sticker shock as these things are very expensive. Here is one brand we've heard about: OVITZ.
Another option can be laser surgery or IOL replacement surgery. If you are a considering any type of laser operation (e.g. LASIK) then we recommend to talk with your ophthalmologist about wavefront correction, if it will be included and potential risks of wavefront abberration errors if the operation is not successful. If you are a candidate for cataract replacement surgery, we recommend to talk with your ophthalmologist about different models of IOL and how they have been tolerated by people who have issues with halos, and risks of developing halos if the lens implantation does not perform as expected.
Can Night Driving Glasses Help?
When someone has a fire, selling water is easy. But, buyer beware. Many purveyors of night driving glasses claim their eyewear will reduce or eliminate blur artifacts such as stars, halos etc. Unfortunately, these claims are not true.
Fortunately, a good pair of night driving glasses can help, but it is helpful to understand that night driving glasses are only able to address the spectral causes of glare (spectral meaning, intensity and wavelength of components of light), but do not address any refractive issues (refracting meaning, focus problems you need a prescription for). If you are suffering from issues such as stars, halos, or floaters, then please consult with a qualified eye care professional to get an updated prescription.
Finally, once you have optimized your prescription glasses (if needed) then a good pair of night driving glasses in the form of a fit-over (over-the-glasses) style is a good solution for use with prescription glasses.
Any questions? If this article did not address your particular vision concern please contact us for further discussion!