Not long after I turned 40, it happened: I found myself having to hold my phone farther away to read emails and text messages.

I booked an appointment with an eye doctor who told me, matter-of-factly, this is what happens in your 40s. Another thing that starts to decline in middle age is hearing. So much for 40 being the new 30!

If untreated,...

Not long after I turned 40, it happened: I found myself having to hold my phone farther away to read emails and text messages.

I booked an appointment with an eye doctor who told me, matter-of-factly, this is what happens in your 40s. Another thing that starts to decline in middle age is hearing. So much for 40 being the new 30!

If untreated, the gradual decline in eyesight can lead to eyestrain and headaches. Hearing loss can cause longer-term problems such as cognitive decline.

Now for the good news: Some new apps can help you figure out whether your vision or hearing is changing over time. The sooner any problems are identified, doctors say, the better off you’ll be.

It’s part of a broader trend toward do-it-yourself healthcare, which carries risks. The makers of these apps all say these tools are meant to be used in between doctor visits and shouldn’t replace eye and ear exams. And doctors warn that apps can’t detect medical conditions such as glaucoma, which can underlie vision problems, or infections that might cause hearing loss.

Vision Tests

The American Optometric Association recommends generally that people between ages 40 and 64 have an eye exam every two years; it recommends annual exams for people 65 and older.

For people like me who don’t need to wear glasses all the time and don’t make annual trips to the eye doctor, determining the right strength for reading glasses can be tricky. You can try readers on at a store while looking at your phone, but when you get home and look at your computer, you might discover the lenses are too strong, or the small type in your favorite magazine is still blurry.

MyReaderNumber app measures the space between user and phone camera to determine the right reading-glasses correction.

Photo: EyeQue

MyReaderNumber, a new $2.99 iPhone app made by vision-testing company EyeQue, uses Apple’s augmented-reality software to measure the distance between the user and the phone’s camera. That allows the app to determine the focusing power needed for near and mid-distance reading.

“When you try on different pairs of glasses, you’re forcing your brain to work with that correction,” said Phoebe Yu,

EyeQue’s vice president of marketing. “It will work for a certain period of time, but if you have the wrong correction and continue to wear the glasses, you will have headaches.”

The app provides two tests: One determines the lens strength required to clearly read things up close (such as your phone or a book) and another determines the strength needed for reading text on a computer.

The tests take a couple of minutes, and you can take them as a guest without signing up for an account (creating an account allows you to save your results). The correction strength you need to see your computer likely will be lower than what you need to see your phone clearly, since computer screens are typically farther away from your eyes than phone screens. You might even need two pairs of reading glasses, one for each activity.

Scores range from +0.50 to +3.00. The company said below +0.25, no power is needed, while the app recommends consulting a doctor for scores above +3.00, since something stronger than readers may be needed.

While the app can be used by people who have general eyeglass prescriptions, they tend to get more regular eye exams and have their prescriptions adjusted frequently for better near-vision correction.

The Verana Vision Test app contains an Amsler grid, which can detect vision problems including macular degeneration.

Photo: Julie Jargon/The Wall Street Journal

The app currently works only with iPhone X and newer models that have Face ID. Google has a similar AR tool for Android, but a spokesman for EyeQue said measurements are inconsistent due to the variety of Android phones.

EyeQue captures your email address—if you choose to create an account—so your results can be saved for future reference. It also captures your birth year, since age plays a role in the calculation of personalized reading numbers. That information isn’t shared with third parties, the spokesman said, and the company says it doesn’t collect further data. The test’s camera use and distance measurement aren’t saved, he added.

Healthcare tech company Verana Health developed a free vision-test app during the pandemic, to help patients monitor changes between visits and to share information with their doctors during telehealth visits. In addition to a standard eye-chart test, which measures visual acuity, the app also contains an Amsler grid, which can detect vision problems stemming from damage to the macula including macular degeneration, a condition that can be caused by aging.

The Verana Vision Test app is available on Apple devices running iOS 11 or later. The company’s privacy policy states that users control the information they store on the app and can delete it at any time. Users can choose to share their info with their doctors.

The American Academy of Ophthalmology has a list of vision-screening apps that work on Android devices.

Hearing Tests

Age-related hearing loss is usually less obvious than age-related vision loss, but is important to identify. Even people with mild to moderate hearing loss can miss out on conversations and other social activity, and social isolation can lead to dementia, according to hearing experts. With lower-cost over-the-counter hearing aids becoming available as soon as this year, it’s worth finding out if you could be a candidate for an assistive device.

I tried out a few apps, but I wasn’t satisfied with the level of information they gave me, a nonmedical person. So I went back to an app I tried out nearly a year ago. Mimi, which is free and highly rated in Apple’s App Store, was developed by a German hearing tech company.

Mimi is a free app to test your hearing, available in Apple’s App Store and integrated into Apple’s Health app.

Photo: Julie Jargon/The Wall Street Journal

My latest results were very similar to my previous results. This gave me comfort because it showed my hearing hasn’t degraded and demonstrates consistency in the testing. The app, which works on iOS and Android devices, offers two different types of tests: One measures the quietest sounds you can hear at different frequencies (and generates an audiogram), while the other measures the quietest sounds you can hear in a noisy environment.

SHARE YOUR THOUGHTS

What tools have you found useful for determining hearing or vision loss?

If you use the app without creating an account, the company assigns you a randomly generated ID to distinguish your results from those of other users without revealing your identity. If you create a free account, your data can be used for research, according to the company’s privacy policy.

Mimi is one of three audiogram apps, along with SonicCloud and Streaks, that are integrated into Apple’s Health app.

Audiologists I’ve interviewed say an app-generated audiogram is a good starting point for a middle-aged person in good health. If it shows any hearing loss, a visit with a doctor is a must.

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Write to Julie Jargon at Julie.Jargon@wsj.com