Tuesday, September 1, 2015

Amsler Grids

Isn't it funny how something you never heard of before can suddenly become a big part of your everyday life? That's what happened to me with Amsler grids.

It started on a warm Thursday morning, May 28, 2015. I was finishing up with my optometrist -- the first stop in a long journey to discover why I was losing vision. My optometrist was puzzled and referred me to a retinal specialist.  As I got ready to leave the office, his white-jacketed assistant handed me a few sheets of paper containing Amsler grids. I stared at them for moment before realizing their purpose.

Named in honor of the Swiss ophthalmologist Marc Amsler (1891 - 1968), the eponymous grids test defects in vision, in particular, macular degeneration. The macula of your retina is responsible for central, high-resolution vision. Macular problems manifest themselves as warped or missing Amsler grid lines. To use an Amsler grid, you stare at it with one eye. If the grid lines misbehave and don't intersect at right angles, then you’ve got a problem.

Marc Amsler
A handful of doctors’ visits after my first encounter with Amsler grids, I learned that I had contracted toxoplasmosis in my left eye. My body mounted a fight and retinal cells in my macula were the collateral damage. If I had known about Amsler grids, would I have caught my vision problem earlier? Possibly. Detecting eye loss problems early is what the Amsler grids were designed to do.

On an Amsler grid, my vision loss manifests itself as a gray hole in the grid with minimal warping. The missing vision is in the space from the center of my left eye to my nose. My brain does the best it can without the information from the missing retina cells, hence a gray spot.

An Amsler grid is simply a sheet of graph paper. That's not to downplay the time Amsler likely spent testing and arriving at this simple diagnostic test. The genius of the Amsler grid is that it turns the subjective into objective. How you use it is what matters. The grid reminds me that checking my eyes is important: every day and everywhere. I see Amsler grids in mullions on windows and doors, stripes on walls, and fences. Even a telephone pole can work as a simple Amsler test.

Now that I know about Amsler grids, I routinely pull out a fresh grid and check my vision, sketching the contours of the missing vision. Looking at grid results over time helps me keep track of what my vision is doing. If the warping changes or grows, then it may be that the toxoplasmosis parasite has awoken and is on the move.

The Ophthalmology Hall of Fame biography suggests that Amsler may have been inspired to create the grid by fellow Swiss ophthalmologist Edmund Landolt (1846 - 1926). However, the biography doesn't give much more detail on how Amsler arrived at the grids. Likely, the complete story rests in private notes and correspondence somewhere, out of sight. All I have for now is the image of Amsler accompanying the biography. In the photo, bow tie askew and wearing a white lab jacket, Dr. Amsler smiles at us from the past. I imagine him saying, "Did you check your eyes today?"

Results of Amsler grid tests showing loss of left eyesight. 

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