By Anne-Marie Lahr, OD

How your retina is functioning may tell us more than we can see in a clinical exam.

It had been a year since I had last seen my brother. It was late in the evening and we decided to stop for a bite to eat on our way home from the airport. It would give us a chance to catch up before we met up with my mom. No one would get in a word after that!

He looked older than I remember, but what struck me the most was his apprehension behind the wheel and the difficulty he had parking the car. I asked when was the last time he had his eyes checked and he said he had seen his optometrist two weeks ago. He said his vision was fine, that he just hated driving at night and the parking spots were too tight.

Clearly, he was having difficulty seeing in dim light. As an optometrist, I knew this was big reason for concern. As a kid sister, it was going to be a bear to convince my older brother to have his eyes checked.

Are you having trouble seeing at night like my brother?

Up until a couple of decades ago, difficulty seeing in the dark was considered a rite of passage, one more challenge brought about by Father Time. Nowadays, multiple clinical studies later, we know difficulty adjusting to changes in illumination (impaired dark adaptation) is a red flag for age-related macular degeneration (AMD).

Unfortunately, trouble seeing in the dark is a symptom of macular degeneration that is often overlooked. The way we currently evaluate the retina is limited to images and visual assessments to identify physical abnormalities, if present. In the case of macular degeneration, we can spot small bumps of cholesterol in the retina, called drusen. Drusen, however, appear later in the disease; when age-related macular degeneration has progressed past its initial stage (subclinical level).

Macular degeneration is sneakier than you think

Eye doctors are trained to examine the retina and take photos to get the best possible images, but this is still a subjective practice. Unfortunately, we aren’t perfect, and studies have shown that ophthalmologists and optometrists alike miss macular degeneration, even when drusen show up in images of the retina. To make matters worse, most of these patients do not seek treatment until their visual acuity declines beyond correction. How can we improve diagnostic accuracy to detect macular degeneration at an earlier stage?

We should assess how the retina is working, in addition to what it looks like. Before drusen can be seen in an exam, a layer of cholesterol accumulates in the retina that blocks nutrients to the cells responsible for the eye’s ability to adjust from bright light to darkness. This, in turn, causes inflammation and the cells die from not getting nutrition. When this happens, we begin having trouble reading in dim light, finding our seats in the movie theater when the lights are turned off, and getting around in the dark, among others. In other words, we experience impaired dark adaptation – the very first symptom of age-related macular degeneration.

Coming out of the dark

After fighting a battle tougher than Gettysburg, I convinced my brother to get a dark adaptation test with an AdaptDx^®. Once done with his visit, I asked how everything had gone. “I’m fine. The doctor said I need to take vitamins and exercise more.”

Given our family history and knowing these are treatments prescribed for age-related macular degeneration, I knew my brother had been diagnosed as having macular degeneration. Thankfully, it seems we caught it early; since other retinal images had not shown physical signs of disease (pesky drusen). Proactive treatment with vitamins, regular exercise, healthy diet, and blue light blocking lenses would help preserve his vision.

“Are you glad you got checked out?” Tight lips and crickets were his response. I smiled. The retired attorney had lost his argument. More than ever, I was glad we have the technology to test dark adaptation and detect early age-related macular degeneration. It could help save my brother’s sight – and mine! (You know I have to get tested!)

“Are you having trouble seeing at night?” has become a routine question when seeing patients older than 50 in many practices. It is of great help to other patients who, much like my brother, may not realize they have age-related macular degeneration.

Word to the wise: Tell your doctor when you notice you’re having trouble getting around in the dark. Even when drusen can’t be seen in a routine exam, dark adaptation testing will help your doctor detect macular degeneration early. Once detected, you can take action to preserve your vision for years to come.

Cheers,

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