Eye Health and Aging: Myopia and Posterior Vitreous Detachment
Since the age of four, I have relied upon eye doctors to keep me seeing well. Both my parents are nearsighted and when their genes mixed, the result was double bad eyesight for me. For those who know how prescription strengths work, I just picked up a new pair of eyeglasses today which are powered at -13.75 in one eye and -13.25 in the other.
Really bad nearsightedness is also known as severe myopia. Myopic eyes are longer than “normal” eyes which tends to stretch the retina. This puts extra stress on the back of the eyes. I remember in high school being warned, kindly but repeatedly, about reporting any sudden change in vision, especially the appearance of “flashes” of light. The doctors who had cared for me since the age of four put the fear of a torn or detached retina in the front of my mind.
When I moved to Washington, DC, I needed a new doctor so I called home for a recommendation. The morning in 2000 when I woke up and couldn’t see well out of my right eye - it appeared as though I was looking through vaseline-covered lenses - my new eye doctor’s quick response ensured that I receive prompt medical attention, resulting in the diagnosis of optic neuritis. This is the first concrete point in time that I can connect directly to the multiple sclerosis diagnosis I later received.
Aging, Vision, and Floaters
During the past ten years or so, my vision finally stabilized. No longer do I require updated prescription lenses each year. However, I did develop a new problem - presbyopia - which is a sign of being “of that age.” With presbyopia, the lens of the eye loses its ability to focus up close. Ever watch “older” folks read the paper way out at arms’ length? Well, I was approaching that situation so now I wear multifocal contact lenses to compensate.
Somewhere along the way, I also developed two “floaters” in my right eye. They are harmless but were a distraction at first. Floaters may have different causes. Mine were explained as the result of little bits of the gel inside the eye (the vitreous) sticking together and creating a shadow on the retina. Uveitis, an inflammation in the eye which can be caused by rheumatoid arthritis, might cause floaters in addition to light sensitivity and blurred vision.
The most common cause of floaters is a posterior vitreous detachment (PVD). The vitreous is the jelly-like substance inside the eye, primarily solid in childhood, which begins to liquify as we age. Think of the vitreous as an inflated balloon which is lightly attached to the retina at the back of the eye. When the vitreous gel liquifies, it begins to shrink and eventually separate from the retina. PVD is very common in older populations.
Retina Eye Specialists, a practice in California, shares that “posterior vitreous detachments occur in around 53% of people over 50 years old and 67% of people over 65 years old.” PVD occurs in only 6% of people under the age of 50.
Risk factors for posterior vitreous detachment:
2. Myopia (nearsightedness)
3. Trauma from decelerating injuries (such as whiplash)
My Posterior Vitreous Detachment Story
Last month when we were preparing for a yard sale, I noticed new floaters in my left eye. Not something which was alarming, but definitely not welcome. During the next day, the amount of floaters increased. I thought to myself that this wasn’t good and I became concerned that this might be a new manifestation of optic neuritis.
Then, I noticed the flashes of light. Uhoh!! I had been warned since childhood that flashes of light = retinal tear or detachment. The flashes increased during Sunday night and I called my eye doctor first thing Monday morning. After a thorough eye exam, I was diagnosed with PVD. I did not in fact have any retinal tears. Phew.
When a PVD develops some patients may not experience any symptoms. Most patients, however, experience floaters in the shape of dots or cobwebs (mine look like inky cobweb curtains) and/or flashes of light. The flashes are caused by electrical stimulation as the vitreous pulls away from the retina. In younger persons, this pulling may be strong enough to cause a retinal tear, which is less common in older persons. However, myopic persons are at increased risk of a tear because their retina is thinner due to being stretched.
After being reassured that I was experiencing something completely normal and benign, I thought to myself that this was one more secret about getting older. I later learned that my father had experienced PVD at the beginning of this year. I guess I’m just a generation ahead of my time.
I’m told that gravity will help to settle the floating, detached vitreous toward the bottom of the eye. The flashes ,which continued for almost three weeks, have subsided. I still see floaters in my central vision, but my brain is learning to adapt to the distraction. Hopefully those floaters will indeed float out of my line of sight. Only time will tell.
If you ever experience any of the following symptoms, please call your doctor immediately:
1. Black curtain coming across your vision
2. Sudden onset of numerous flashes
3. Sudden onset of a floaters that look like sand
4. Sudden blind spot in your side vision
Posterior Vitreous Detachment and Retinal Tear, Retinal Eye Specialists, accessed online August 23, 2012.
Vitreous Floaters, Retinal Diagnostic Center, accessed online August 23, 2012.
Information provided by my own eye doctors.