Tag: peripheral vision

Eyes on the Road

Karen Griffith

Shorter days and rainy weather, both contribute to difficulty driving. A driver’s vision guides 90% of driving decisions, so good eyesight is essential for road safety.

On the Road

Start with an eye examination to assess clarity, peripheral vision and eye disease. Having the proper vision skills and prescription are important for many reasons:

Distance vision is imperative for judging distances and reaction time when driving. Poor distance vision increases the risk of making unreliable judgments with potentially disastrous results – even the simplest reactions take 0.4 seconds, so if distance vision is poor, signs or objects may not be seen until it is too late to react safely.

Good Peripheral Vision allows drivers to survey the area without looking away from the road. This includes early recognition of cross-traffic, pedestrians, animals, signs and changes in traffic flow. Impaired peripheral vision can result in the driver failing to react to a hazard on the far left or right, failing to stop at a stoplight suspended over an intersection, weaving while negotiating a curve, or driving too close to parked cars.

Safe Night Driving requires the ability to see in low light conditions and with poor contrast. Impaired night vision can result in tailgating, failing to steer when necessary (since it is difficult to see low contrast features such as edges or irregularities in the road surface), and recover from glare of oncoming headlights.

Glare refers to the disruption of vision due to veiling luminance. Important visual skills for drivers are glare resistance – the extent to which the driver can still see critical objects while facing a steady source of glare (setting sun, headlights), and glare recovery – the rapidity with which the driver’s functioning vision returns to what it was before the glare was encountered. If these skills are not adequate, the driver can miss curves, strike an animal or pedestrian or crash into slow moving or stopped vehicles.

Besides regular eye exams, additional tips for good vision while driving include:

  • Always wear sunglasses when driving to reduce glare
  • Keep headlights, tail lights , windshields and eye glasses clean
  • Keep side and rear view mirrors adjusted correctly to increase your field of vision and reduce glare from headlights
  • Always wear glasses or contact lenses if they have been prescribed for driving

What is Glaucoma?

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Glaucoma is a group of eye diseases in which the pressure inside the eye may or may not be elevated. If untreated, vision loss or blindness may occur.

glaucoma prevention

January is Glaucoma Awareness Month
Unfortunately, the most common type of glaucoma – open angle, causes no symptoms. Vision doesn’t change, and there is no pain. However, as the disease progresses, a person with glaucoma may notice his or her side vision gradually failing. That is, objects in front may still be seen clearly, but objects to the side may be missed. As the disease worsens, the field of vision narrows and blindness results.
Studies have shown that early detection and treatment of glaucoma, before it causes major vision loss, is the best way to control the disease. So, if you fall into one of the high-risk groups for the disease, make sure to have your eyes examined annually. Individuals at high risk for glaucoma include African Americans over the age of 40, everyone over 60 and people with a family history of glaucoma.

There isn’t a single test to diagnose glaucoma. Drs. Griffith and Staton examine the appearance of the optic nerve, the intra-ocular pressure and visual field results. Further testing such as measurement of the corneal thickness (pachymetry), examination of the anterior chamber and measurement of the  integrity of the nerve fiber layer can be helpful in the diagnosis and treatment of glaucoma.

Schedule your appointment.

BOOK REVIEW: The Mind’s Eye

Karen Griffith

The author of The Mind’s Eye., Oliver Sacks, is a neurologist who has written books on the various senses, brain function and dysfunction and perception. He makes challenging, vague Vintage-Minds-Eye-2011-194x300topics more obtainable to the layperson.
The Mind’s Eye is about different visual perception related conditions ranging from agnosia (inability to recognize and name objects), stereopsis, and peripheral vision.
Of the seven different topics/chapters my favorites were “Stereo Sue” and “Persistence of Vision.” Susan Barry is a neuroscientist who had been cross-eyed since infancy. Susan had strabismic surgery as a child to straighten her eyes but lacked fusion, the 2 eyes didn’t work together.She grew up viewing a flat world until she finally met an optometrist who created a vision training program for her. Due to her motivation and interest in perception she succeeded in obtaining stereo vision. Her two-dimensional world became three-dimensional. She has written a book about her journey into three dimensions – Fixing My Gaze. If you are interested in stereopsis, have a strabismic child or lack depth perception yourself I strongly recommend her book.

“Persistence of Vision”  is a journal of Oliver Sacks’ own experience slowly losing vision  in one eye due to a tumor. He scolds himself for missing his annual eye exams which would have detected the tumor earlier. Losing his vision in one eye caused the loss of stereovision and peripheral vision. As a neurologist, Sacks analyzes not only the loss of peripheral vision but the loss of awareness in the visual field. He had to learn to deal with moving around without awareness of objects to his right, this resulted in a lot of bruises on the right side of his body.

In the first pages of the book, Sacks describes the human variation in visual imagery, peoples ability to visualize something without actually seeing it. At the end of the book he gives examples of individuals who have profound enhancement of the remaining senses when one is lost and other individuals who don’t gain sensitivity. The one consistent factor of the brain and human perception is that it isn’t consistent.

My one complaint of the book is the footnotes on nearly every page. By the end of the book I was annoyed to the point where I had to ignore the footnotes to finish reading the text.