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Early signs of macular degeneration, and when to see an eye doctor

Judi Dench says macular degeneration has taken her ability to read and act. Here’s what to watch for and when to see an eye doctor

Age-related macular degeneration often starts quietly. In its early stage, the condition frequently causes no symptoms at all, and a person can carry it for years with vision that seems normal. When changes do appear, they tend to be small: a bit of haze while reading, a door frame that looks slightly crooked, a need for a brighter lamp. Many people put these down to getting older and move on.

That habit can delay care. The National Eye Institute identifies AMD $AMD as a leading cause of vision loss among adults age 50 and up in the U.S. The disease targets the macula, a small area at the center of the retina responsible for the sharp detail people rely on when they look straight at something. Peripheral vision usually survives. As a result, AMD seldom leads to complete blindness. The damage falls in the middle of the visual field instead, the part used for reading, driving and recognizing faces.

AMD comes in two forms. Dry AMD is the more common type and moves slowly. Wet AMD, sometimes called neovascular AMD, develops when abnormal blood vessels form beneath the retina and leak fluid or blood. It occurs less often, but it can cause severe central vision loss quickly. A dry case can also convert to the wet form. A dry AMD diagnosis therefore still calls for ongoing monitoring.

Knowing the early signs of macular degeneration gives people a way to tell an ordinary visit from an urgent one. Some signs are things a person notices, such as blur, distortion or a gap in the center of what they see. Others show up only in an eye doctor's chair, during a dilated exam or a retinal scan. A few checks can happen at home between appointments.

The 10 slides that follow cover a selection of these signs and steps, not every possible symptom. They describe what each change looks like, why it happens and what it means for timing. They also cover who faces higher risk and how often to book an exam. None of them replaces a professional diagnosis. Several of these changes overlap with other eye conditions, and only an exam can sort them out.

Blurry central vision that glasses don't fix

A soft, hazy patch in the middle of whatever you look at can be a sign of age-related macular degeneration (AMD $AMD). The edges of your sight may stay fairly sharp, and a new eyeglass prescription does not fully clear the blur.

The reason lies in where the damage happens. The macula is a small area at the center of the retina, the light-sensitive tissue lining the back of the eye. It handles the fine, straight-ahead detail needed to thread a needle or read the time on a wall clock. When AMD damages the macula, the central part of the image loses its crispness.

Glasses and contact lenses solve a different problem. Nearsightedness, farsightedness and astigmatism occur when the cornea and lens bend incoming light so that it lands slightly off target. A corrective lens shifts that light back into place. AMD involves the retina itself. Even perfectly focused light then falls on tissue that can no longer render detail clearly. A camera offers a rough comparison. Cleaning or swapping the lens will not fix a worn-out sensor.

In daily life, the blur tends to sit exactly where attention goes. A street sign straight ahead can look fuzzy even though parked cars to either side are easy to make out. A coffee mug in the middle of a table may look smeared while the plates around it stay crisp.

The change can begin in one eye. When that happens, the other eye can compensate, and the blur may go unnoticed until the stronger eye is covered by chance.

Cataracts can also make vision look cloudy. A cataract clouds the eye's natural lens and is treated with surgery. Its haze tends to spread across the whole view rather than gathering in the center. The two conditions can occur together. Only an eye exam can show which one is behind the blur.

Anyone whose updated glasses still leave the middle of their vision soft should mention it to an eye doctor and ask whether a dilated exam is needed.

Wavy or bent lines (metamorphopsia)

Straight lines that look wavy, bent or warped can be an early sign of macular degeneration. Eye doctors call this distortion metamorphopsia. It is one of the classic symptoms of age-related macular degeneration, or AMD $AMD.

The effect is easiest to see on objects a person already knows are straight. The edge of a door frame may seem to bow in the middle. A line of printed text can look as if it ripples across the page. The grout between bathroom tiles may appear to kink or sag in one part of the pattern while the rest looks normal.

The distortion starts in the macula. This patch of retina sits at the back of the eye and supplies the sharp vision used to look directly at something. The light-sensing cells there sit in a tightly ordered layer. When something pushes that layer out of shape, the cells no longer line up the way the brain expects. The picture the brain builds from them comes out bent to match.

With AMD, that push often comes from fluid. In wet AMD, also called neovascular AMD, abnormal blood vessels form beneath the retina and seep fluid or blood into nearby tissue. That buildup can lift and wrinkle the macula. Metamorphopsia is linked especially closely to this process. Because wet AMD can cause rapid loss of central vision, new distortion is a warning sign worth acting on.

The bent area tends to stay in the same spot within a person's field of view. It travels with the gaze, so whatever sits directly in the center of sight is the thing that looks warped.

Distortion is easy to........

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