The blindness
that could have been prevented

Glaucoma does not take your sight all at once. It trims it from the edges.

It is damage to the optic nerve. It often comes with high eye pressure, but it also happens with normal pressure. That is why measuring pressure is not enough: the nerve and the visual field have to be checked.

Because the center stays intact, you keep reading, watching TV and driving. The brain fills in the gaps. When someone finally says "something is wrong," the tunnel is already narrow.

Risk rises after 60, with a parent or sibling who has glaucoma, with diabetes, with strong nearsightedness and with long-term cortisone use. And it rises for Latinos: in Los Angeles, 4.74% of Latinos 40 and older had open-angle glaucoma, and 75% did not know it.

Treating early works. In the EMGT trial, funded by the U.S. National Eye Institute, glaucoma progressed in 45% of treated patients versus 62% of untreated patients over six years.

Here is the first saving, and it is huge. Latanoprost is one of the most used glaucoma drops. In Mexican pharmacies, the generic costs MX$121 a bottle. The original brand, Xalatan, costs MX$1,111. The same molecule, nine times the price.

At one bottle a month, the difference is MX$11,880 a year. In the United States the gap is wider: at the acquisition prices Medicaid publishes, the generic comes to about $47 a year and the brand to about $3,250.

Do not switch your drops on your own. Ask your ophthalmologist whether the generic is an option for you.

Arriving late has a price too. Advanced glaucoma often needs several drops at once. With two brand-name bottles a month, Xalatan and a triple combination, the bill rises to MX$25,716 a year. If pressure does not come down, surgery follows: a trabeculectomy costs MX$9,770 per eye at the public fee of the Guerrero State Ophthalmology Institute.

In the United States, a Duke University study measured the direct cost per patient: $623 a year at an early stage versus $2,511 at end stage. Four times more for arriving late, with the sight already gone.

If you live in the United States: Medicare Part B pays for a glaucoma test every 12 months if you are Hispanic and 65 or older, if you have diabetes or if glaucoma runs in your family. You pay 20% after the deductible.

Longevity Eyes includes a quick visual field test that looks for blind spots at the sides, like the ones glaucoma leaves. It does not replace your ophthalmologist's perimetry: it tells you whether you need to go now. And you can log your pressure, your OCT scan and your tests to see the trend year after year.

With macular degeneration you can see the wall clock, but not your grandchild's face.

The macula is the center of the retina, just a few millimeters wide. You use it to read, sew, drive and recognize faces. It wears out with age. The dry form advances slowly. The wet form, with new vessels that bleed, advances in weeks.

It does not cause total blindness: it erases the center and leaves the edges. But living without the center means living without reading, without driving and without faces.

Mexico has no official count. The pharmaceutical industry itself estimates about 1.5 million people 50 and older with the disease.

On the left, a healthy retina: the dark spot in the center is the macula. On the right, a retina with drusen, the yellow dots that are deposits and signal intermediate macular degeneration. This is what the inside looks like before anything is felt outside.

The wet form is treated with injections into the eye. They are the standard treatment. The aflibercept label calls for three monthly doses and then one every two months: about seven in year one.

A vial of aflibercept costs MX$26,530 at a Mexican pharmacy. Medicare, in the United States, pays $1,444.50 for it: about MX$27,160. Practically the same price, with wages that look nothing alike.

Seven vials come to MX$185,710 for the drug alone, for one eye. Add the injection fee, about MX$4,500 to MX$5,000 each time in Mexico City, and year one tops MX$218,000. In the United States, at 2026 Medicare rates, it comes to about $11,200 per eye.

Here is the reason to measure at home. The injection costs the same whether you arrive early or late. What changes is how much sight you save.

In the CATT trial, patients who started treatment still seeing 20/25 to 20/40 ended the year at 20/32. Those who arrived seeing 20/100 to 20/160 ended at 20/63. In the HOME study, people who monitored their vision at home with a device reached diagnosis with a median loss of 4 letters; those who waited for their appointment, 9.

If your ophthalmologist says you have intermediate macular degeneration in one or both eyes, or advanced in one eye, the AREDS2 formula lowered the risk of reaching the advanced stage by about 25% over 5 years in the National Eye Institute study. In healthy eyes it prevents nothing. Quitting smoking is the biggest thing you can change.

Cataract is the leading cause of blindness in Mexico. And it is the only one solved in a single morning.

The crystalline lens, the eye's natural lens, turns opaque. Colors fade, lights glare at night and new glasses no longer help. Surgery replaces that lens with an artificial one.

In Querétaro it caused 29.8% of blindness in adults 50 and older. The study asked why people were not getting surgery. 38.3% said they could not afford it.

Mexico's Deputy Health Ministry speaks of more than 760,000 people with cataract and acknowledges that about a third are not operated on for lack of money or access. The IMSS opened night and weekend shifts to perform 11,305 extra cataract surgeries between October 27, 2026 and February 24, 2027. Nobody opens night shifts without a line.

Waiting costs too, even if it never shows on an invoice. In a JAMA study of Medicare patients, cataract surgery was associated with 16% fewer hip fractures in the following year. Another study, in JAMA Ophthalmology, found 9% fewer serious car crashes. A hip fracture at 75 is not fixed in a morning.

Contrast sensitivity drops before acuity does with cataract. Longevity Eyes measures both from your phone, once a month, so you see the trend and walk into your appointment with data.

Almost one in five Mexican adults has diabetes. Almost a third of them do not know it. Their eyes do.

According to ENSANUT 2022, 18.5% of adults in Mexico live with diabetes, and about 31% of them had no diagnosis. High sugar damages the retina's tiny vessels: they clog, bleed and fragile new vessels grow. In the Querétaro study it was the second cause of blindness, at 17.5%.

The most painful figure is official: 57.7% of type 2 diabetes patients hospitalized in the Health Ministry's surveillance network had never had an eye exam. That is out of 42,402 patients in the 2023 report.

Among Latinos in Los Angeles, 46.9% of diabetics already had retinopathy. In the United States, diabetes affects 11.7% of Hispanics versus 6.9% of non-Hispanic whites. And in Medicare, only 48.2% of Hispanic diabetics had an eye exam in 2017, versus 55.6% of whites.

A dilated fundus exam costs about MX$1,200 in Mexico City. Laser to stop retinopathy, MX$4,000 to MX$9,586. A vitrectomy, once blood has filled the eye, about MX$40,000 privately and MX$14,400 at Guerrero's public fee. A yearly fundus exam versus a vitrectomy: 33 times.

If you live in the United States: Medicare covers a diabetic retinopathy eye exam once a year if you have diabetes.

Put the prices side by side and the conclusion writes itself.

The United States spends $134.2 billion a year on vision loss and blindness, according to the study by Rein and colleagues published in Ophthalmology in 2022, with 2017 data.

Latinos will carry a growing share. A JAMA Ophthalmology study projects their share of the country's visual impairment cases will rise from 9.9% to 20.3% by 2050. And 21.9% of Hispanic adults ages 18 to 64 have no health insurance, versus 8.5% of whites.

Mexico has no official figure for what blindness costs it. The investment case by the International Agency for the Prevention of Blindness (IAPB) estimates that each dollar invested in eye health in Mexico between 2026 and 2030 would return about 35. It is a model from a civil society organization, not an official figure, but the direction is clear.

An honest caveat. The expert panel that advises the U.S. government on prevention (USPSTF) says there is not enough evidence to recommend glaucoma screening for all adults without symptoms. This investigation does not ask everyone to get screened. It asks people at risk to get checked. And if you are Latino, over 60 or diabetic, that is you.

Check your profile. The tool adds up published prices in Mexico and shows what keeping watch costs versus what arriving late costs.

I built a tool so you do not wait for the symptom.

Longevity Eyes lives inside Longevity Lab. It is a set of home tests on your phone or computer, calibrated with a card so the measurements are real, plus a record of your eyes you can take to your ophthalmologist. The app is in Spanish.

Often the risk is not in the eye. It is in the medicine cabinet.

Tap each card. And one rule before anything else: do not stop any medicine on your own. Talk to whoever prescribed it.

The rule is simple: at 40, your first complete exam. After that, more often with each decade.