Farsightedness After 40: Why Reading Gets Harder and How Treatment Adapts

The restaurant lighting was fine last year. This year the menu has quietly moved out of reach, so you tilt it toward the candle, hold it a little farther away, and finally hand it to the person across the table. Nobody says anything. Everybody has noticed.

That small moment is how farsightedness after 40 tends to announce itself: not with a bang but with a menu, a pill bottle, a text message that suddenly needs a longer arm. The eyes have not failed. They have simply reached a stage that almost every human eye reaches, and the print has stayed exactly the same size.

What follows is an honest tour of why near vision changes in midlife, how it differs from the farsightedness some people are born with, and how the options for managing it shift as the years go on. None of it is a substitute for an eye exam. All of it should make the exam, and the conversation afterward, a good deal easier.

How does the eye focus, and what changes with farsightedness after 40?

Think of the eye as a camera with two lenses stacked in series. The cornea, the clear dome at the front, does most of the heavy lifting and never changes its power. Behind it sits the crystalline lens, a soft, flexible disc about the size of a lentil, held in a ring of tiny fibers attached to a circular muscle called the ciliary muscle.

When you look at something close, that muscle contracts, the fibers slacken, and the lens bulges into a rounder shape. A rounder lens bends light more strongly, pulling the focus forward onto the retina, the light-sensitive layer at the back of the eye. This automatic refocusing is called accommodation. It happens hundreds of times a day without a thought.

The catch is that the lens keeps growing throughout life. New fibers are laid down on the outside while the older ones are compressed toward the center, and over decades the whole structure becomes denser and less elastic. The ciliary muscle still squeezes, but the lens no longer rounds up as much. The nearest point you can focus on drifts slowly outward, year by year, until one day it slides past the distance at which you normally hold a book. That is presbyopia, and according to Mayo Clinic it usually becomes noticeable in the early to mid-40s and continues to worsen until around age 65.

Nothing in this process is a disease. The National Eye Institute describes presbyopia as a normal part of aging, and MedlinePlus notes it happens to essentially everyone. What varies is when it becomes a nuisance, which depends on how much focusing reserve you started with, how close you like to hold things, and how much fine print your day contains.

Presbyopia vs hyperopia vs astigmatism: what is the difference?

Three very different problems get lumped together under the word farsighted, and the confusion matters because the fixes are not identical.

Presbyopia is the age-related stiffening described above. Hyperopia, the condition doctors usually mean by farsightedness, is structural: the eyeball is a little too short from front to back, or the cornea is a little too flat, so light focuses behind the retina rather than on it. The NHS explains that many people with mild hyperopia see clearly at every distance in youth because their flexible lens quietly compensates. Astigmatism is a shape issue in which the cornea or lens is curved more steeply in one direction than the other, a bit like the back of a spoon rather than a ball, so light forms a smeared focus instead of a single point.

Condition	What is happening	Typical onset	Effect on reading
Presbyopia	Lens stiffens and cannot round up for near focus	Early to mid-40s (Mayo Clinic)	Near print blurs; distance often unchanged
Hyperopia	Eye too short or cornea too flat; focus lands behind retina	Present from childhood, often masked until midlife (NHS)	Near blurs first, later distance too; eyestrain, headaches
Astigmatism	Uneven curvature scatters focus in one direction	Any age; usually present from birth (NHS)	Blur or smearing at all distances; letters may look tilted or shadowed

The three often coexist. A person can carry lifelong mild hyperopia and a touch of astigmatism, sail through their 30s without glasses, then find presbyopia removes the compensation all at once. That combination is one reason the first pair of readers sometimes disappoints: it fixes the age part but not the shape part. Only a refraction, the measurement an optometrist or ophthalmologist performs with lenses and charts, can tell the three apart.

Why did I suddenly become farsighted?

The honest answer is that it almost certainly was not sudden. The lens has been losing flexibility since childhood, but the loss is invisible until the near point crosses the distance at which you actually read. Cross that line and a decade of gradual change shows up in a single week, usually in poor light and small type. Mayo Clinic describes exactly this pattern: symptoms that seem to appear abruptly around the mid-40s.

A second quiet mechanism is unmasked hyperopia. Someone who has always been mildly farsighted has been using accommodation to focus at distance as well as near. When the reserve runs low, both distances start to slip, and the person may describe it as their eyes “going” all at once. The prescription that results is often the first they have ever had, which adds to the sense of suddenness.

Genuinely rapid shifts in focusing deserve more attention. Mayo Clinic lists diabetes, multiple sclerosis and cardiovascular disease among conditions associated with earlier-than-expected presbyopia, and notes that some commonly prescribed medicines, including certain antidepressants, antihistamines and diuretics, can affect focusing. Swings in blood sugar can temporarily alter the lens and change a prescription within weeks. An early cataract, a clouding of the lens, can also nudge the refraction in either direction.

None of this means a new pair of readers is a medical red flag. It does mean that a change that arrives over days rather than months, that affects one eye more than the other, or that comes with pain, halos or a headache should be described plainly to the examining clinician rather than attributed to age alone. The examination is the same; the questions asked during it are what differ.

What does astigmatism look like, and how bad is mine?

People with astigmatism rarely describe simple blur. They describe smearing. A streetlight at night grows a tail. The letter E acquires a faint twin sitting just above it. Thin lines in one direction look crisp while lines at right angles look soft. The NHS notes that headaches and eyestrain are common companions, especially after long reading or screen sessions, because the eye keeps trying to resolve an image that cannot be resolved by effort.

The reason is geometry. A perfectly round cornea focuses light to a point. A cornea curved more steeply along one meridian focuses that meridian in front of the other, so the image is stretched into two lines at slightly different depths. Glasses correct this with a cylindrical lens ground to the opposite shape, which is why an astigmatism prescription has an axis, the angle in degrees at which the correction sits.

Severity is read off the prescription itself. Look for the column labeled CYL, short for cylinder, measured in diopters. A diopter is the unit of focusing power, defined as the strength of a lens that brings parallel light to a focus one meter away. The larger the CYL number, ignoring the plus or minus sign, the more correction the eye needs. Clinicians describe astigmatism as mild, moderate or high along that scale, and the vast majority of adults sit at the mild end, where the effect is a soft edge rather than a disability. Rather than fixating on a cutoff, ask the examiner two questions: does this amount of astigmatism explain my symptoms, and has it changed since my last visit.

Change is the more useful signal. Ordinary astigmatism is usually stable through adulthood. A measurement that keeps climbing, particularly in a younger adult who rubs their eyes a lot, prompts a closer look at the cornea, because a rare progressive thinning condition called keratoconus can masquerade as ordinary astigmatism in its early years.

What are the treatment options for farsightedness after 40?

Here is the reframing that helps most people relax: presbyopia is managed, not repaired. No option restores the young lens. Every option instead supplies, in some form, the extra focusing power the lens can no longer deliver, and the best-fitting form changes as the eye keeps aging.

The menu, according to Mayo Clinic and the Cleveland Clinic, runs roughly like this:

• Spectacles, in single-vision reading, bifocal, trifocal or progressive designs.
• Contact lenses, either multifocal designs or a monovision arrangement in which each eye is corrected for a different distance.
• Prescription eye drops that temporarily narrow the pupil to extend the range of clear focus.
• Surgical routes, including laser reshaping of the cornea and replacement of the natural lens with an artificial one that has more than one focal zone.

What matters more than the list is the trajectory. In the early years, when the missing power is small, the simplest tools work well and the trade-offs are minor. Mid-course, as distance vision may also begin to slip, people often move to designs that handle several distances at once. Later, when a cataract begins forming, the decision about lens surgery becomes a decision about presbyopia too, because the artificial lens chosen at that operation determines how much near vision is built in afterward.

Every one of these options carries a cost in something other than money: field of view, night vision, adaptation time, or the need to still keep a pair of glasses in a drawer. A good consultation is less about which option is best and more about which compromise you can live with cheerfully. That judgment sits with you and the eye care professional who has measured your eyes, seen the health of the retina and cornea, and heard how you spend your days.

Reading glasses after 40: single-vision, bifocal or progressive?

The oldest solution remains the most widely used, and for good reason. A pair of reading glasses simply adds the plus power the lens can no longer generate. Ready-made readers from a rack provide the same power in both eyes and no astigmatism correction, which suits a surprising number of people in the early years and disappoints the rest. Prescription readers match each eye individually and can include the cylinder for astigmatism, which is why a first refraction is worth having even if the plan is to buy something inexpensive afterward.

Single-vision readers have one obvious limitation: the room blurs the moment you look up. Bifocals solve that with a visible line, the top half for distance, the bottom segment for near. Trifocals add a middle band for arm’s-length tasks such as a dashboard or a desktop screen. Progressives, the design most people now choose, blend the same three zones into a gradient with no visible line, so the eye slides from distance at the top to near at the bottom.

Progressives ask something in return. The side edges of the lens carry distortion, so peripheral vision through them can swim, and the reading zone is narrow, which means moving the head rather than the eyes to scan a page. Mayo Clinic describes an adjustment period that most people work through, while a minority never take to the design and return to lined bifocals or two separate pairs.

One practical point gets missed in the shop. Reading distance varies with the task. Sheet music on a stand, a laptop, a phone in bed and a paperback at the table all sit at different distances and need slightly different power. People who spend hours at a screen often do better with a dedicated pair set for that distance than with a general-purpose progressive. Tell the fitter how you actually live; the prescription is only as good as the description it is based on.

Contact lenses for presbyopia: multifocal and monovision explained

Contact lens wearers who reach their mid-40s often assume their contact lens days are over. They are not, but the physics changes. A contact lens sits on the eye and moves with it, so it cannot offer separate zones you look through by tilting your head the way spectacles can. Designers have taken two very different routes around that problem.

Multifocal contact lenses build the distance and near powers into concentric rings or a gradient across the same lens. Light from both far and near objects reaches the retina simultaneously, and the brain learns to attend to whichever image is sharp for the task at hand. The result, in most wearers, is usable vision at several distances with some loss of crispness at each. Contrast in dim light tends to suffer most, so night driving is the complaint fitters hear first.

Monovision takes the opposite approach: one eye, usually the dominant one, is corrected for distance and the other for near. Each eye sees one range sharply, and the brain suppresses the blurrier image. Mayo Clinic notes the trade-off plainly. Depth perception, which relies on two eyes seeing the same scene, is reduced, and some people never stop noticing the imbalance. A modified version leaves the near eye slightly under-corrected so both eyes share more of the middle range.

A trial is the only real test. Most fitters will lend diagnostic lenses for a week or two so the wearer can judge them in their own kitchen and car rather than in the examination room. Whether the eye can tolerate contact lenses at all is a separate question, because the tear film thins with age and dryness becomes more common after 40. Any redness, pain or sudden blur in a contact lens wearer is a reason to remove the lens and seek care the same day.

Is surgery an option for presbyopia or hyperopia?

Surgery for near vision exists, and it is worth understanding what it can and cannot do before the topic comes up in a consultation. Mayo Clinic groups the procedures into two families: operations on the cornea and operations that replace the natural lens.

Corneal laser procedures, including LASIK and PRK, reshape the front surface with an excimer laser. For someone with hyperopia, the laser steepens the central cornea to bring the focus forward. Laser reshaping cannot restore the lens’s flexibility, so surgeons who use it for presbyopia typically aim for monovision, with the same depth-perception trade-off described for contact lenses, or a blended profile that gives each eye a wider but softer range. A contact lens trial of monovision is often suggested first, because it is reversible and surgery is not.

Refractive lens exchange removes the natural lens and replaces it with an artificial intraocular lens, using the same steps as cataract surgery. Multifocal and extended-depth-of-focus implants split or stretch incoming light to provide more than one focal range. The gains in near vision come with a recognized cost: halos and glare around lights at night, reduced contrast, and in some people a lingering sense that nothing is perfectly sharp at any distance. Some still need glasses for fine print. Because the surgery enters the eye, it also carries the risks of any intraocular operation, including infection, swelling of the retina and retinal detachment, all uncommon but serious.

Corneal inlays, tiny devices placed inside the cornea of one eye, have been tried; the supporting evidence remains thinner and shorter-term than for the other approaches, and their availability has been inconsistent. A candid surgeon will describe them that way.

Suitability, sequencing and whether surgery makes sense at all are decisions that rest with the treating team, informed by corneal thickness, the state of the lens and retina, tear film health and the patient’s own tolerance for compromise.

Do eye drops for presbyopia work, and what does the evidence show?

The newest arrival is a class of prescription eye drops that borrow a trick photographers have known for a century. Shrinking the aperture of a camera increases depth of field, so more of the scene is in acceptable focus at once. The eye’s aperture is the pupil, and a small pupil does the same thing for the retina.

These drops, based on the generic medicine pilocarpine, work by contracting the muscle that constricts the pupil. The Cleveland Clinic and Mayo Clinic both describe them as an option for adults with presbyopia. The medicine does not change the lens at all; it narrows the beam of light so that near objects, which the stiff lens can no longer fully focus, still produce a tolerably sharp image. Effects begin within a short time after instillation and wear off over the course of the day, so the drop is used on the days near vision matters and skipped on the days it does not.

The evidence supporting them comes from randomized trials that measured improvement in near reading on standardized charts, with the benefit most consistent in people in their 40s and early 50s whose presbyopia is mild to moderate. What the trials did not show is that the drops replace glasses for everyone, or that they help once the lens has fully stiffened.

Side effects follow directly from the mechanism. A small pupil admits less light, so dim rooms and night driving become harder. Headache or a dull ache around the brow is common in the first weeks as the focusing muscle also contracts. Rare reports of retinal detachment led regulators to advise caution in people with high myopia or prior retinal problems, and a dilated retinal examination is generally recommended before starting.

Whether these drops are appropriate, how they fit alongside glasses, and how long to continue are decisions for the prescribing clinician, who weighs the mechanism against the individual eye in front of them.

Who each option usually suits, and who is usually asked to wait

Age, occupation and eye health sort people toward different tools more reliably than preference does.

Someone in their mid-40s with good distance vision and a small near deficit is the classic candidate for simple readers or, if they want to skip the on-and-off routine, a low-power progressive. The same person, if already a happy contact lens wearer, may be offered a multifocal or monovision trial. Pupil-narrowing drops are generally considered in this earlier window too, when the missing power is modest and the retina is healthy.

By the mid-50s, when Mayo Clinic notes presbyopia is still progressing and distance vision may also have started to change, the options that handle several distances at once tend to make more sense, and the conversation about eventual lens surgery begins to be realistic, because an early cataract may be present.

Certain people are usually asked to wait, or steered elsewhere:

• Anyone whose prescription has changed noticeably within the past year is asked to let it settle before committing to surgery.
• People with untreated dry eye are often treated for that first, because both contact lenses and corneal laser surgery worsen it.
• Those with thin or irregular corneas are generally not offered corneal laser procedures.
• People with retinal disease, prior retinal detachment or very high short-sightedness are typically counseled away from pupil-narrowing drops.
• Anyone with uncontrolled diabetes may be asked to stabilize blood glucose before any refractive decision, since the lens can shift with it.

Being asked to wait is not a rejection. It is the clinician protecting the result. Every eye care professional would rather fit glasses this year and revisit surgery in two than operate on an eye that is still moving. The final call on timing and suitability rests with the treating team, who can see what no article can: the actual cornea, lens and retina.

The first days and weeks with a new prescription: what adapting usually feels like

Expect strangeness. A first pair of readers makes the page leap forward and the floor, when glimpsed over the top, look oddly far away. A first pair of progressives can make stairs feel steeper and doorways lean. The Cleveland Clinic and Mayo Clinic both describe this adjustment period, and most people find it settles over a couple of weeks of consistent wear, provided they actually wear the glasses rather than reaching for them only in desperation.

A few habits shorten the learning curve. Point your nose at what you want to see, so the reading zone of a progressive lines up with the print. Turn the head, not just the eyes, when scanning a wide page. Sit up straight at a desk, because slouching pushes the near zone out of position. Give the lenses a fair run of daily wear before deciding they are wrong; a genuinely wrong prescription usually produces headache or double vision from the first hour, which is a reason to go back rather than persevere.

Contact lens wearers adapting to multifocals or monovision are on a similar timetable, with the added wrinkle that the brain is learning to prioritize one image over another. Most fitters schedule a check at one to two weeks to fine-tune powers.

Surgical timelines differ by procedure. Corneal laser patients commonly report functional vision within days with fluctuation over the following weeks. Lens exchange patients usually see the operated eye clear over days, but the brain’s adjustment to a multifocal implant, especially the halos at night, can take longer, and surgeons often advise judging the outcome only after both eyes are done and the eyes have settled. These are typical patterns described by the sources above, not guarantees, and the surgeon’s own follow-up schedule takes precedence.

Through all of it, lighting is the cheapest upgrade. Presbyopic eyes need more light to read comfortably, and a brighter lamp aimed at the page often does as much as a stronger lens.

What people often get wrong about farsightedness after 40

Myths cluster around presbyopia because it arrives at an age when people are primed to blame themselves.

“Glasses make your eyes weaker.” They do not. The lens stiffens on its own schedule regardless of what sits in front of it. What glasses change is your perception: once you have seen sharp print again, blur you tolerated for years becomes intolerable, which feels like decline but is only contrast.

“Eye exercises can reverse it.” No exercise program has been shown in mainstream evidence to soften the lens or restore accommodation. Focusing drills can relieve the sensation of strain after long screen use, which is worthwhile, but that is a different claim.

“I can keep my astigmatism from getting worse if I try.” Ordinary astigmatism is largely fixed by the shape you were born with and tends to stay stable in adulthood, so there is little to prevent. The one useful habit is to stop rubbing your eyes, since forceful rubbing is discouraged for corneal health, and to report any steady rise in the cylinder measurement so the cornea can be examined.

“Reading in dim light damages the eyes.” It tires them and makes presbyopia more obvious, since a dilated pupil reduces depth of field, but it causes no structural harm.

“Cataract surgery fixes presbyopia automatically.” Only if a lens designed for near vision is chosen and its trade-offs accepted. A standard single-focus implant set for distance leaves most people needing readers.

“Once I need readers, my eyes are failing.” The National Eye Institute is explicit that presbyopia is a normal consequence of aging, not a disease. The same exam that confirms it also checks the pressure inside the eye and the health of the retina, which is where the genuinely preventable losses of midlife hide.

Questions to ask your care team

The most useful consultations are the ones where the patient has a list. Bring these, and add your own.

• Is my reading difficulty presbyopia alone, or is there hyperopia or astigmatism underneath it, and how much of each?
• Has my prescription changed since the last visit, and by how much? Is the pace of change what you would expect for my age?
• Did today’s exam include a check of eye pressure and a look at the retina and optic nerve? If not, when should that happen?
• Given how I spend my day, which lens design would you try first, and what should I expect to dislike about it?
• Would a dedicated pair for my screen distance help more than a general progressive?
• Am I a reasonable candidate for a multifocal or monovision contact lens trial, and how long would you want me to test them?
• Are pupil-narrowing eye drops something you would consider for me, and what in my eyes would argue against them?
• If I am ever a candidate for surgery, which type, and what would make you say not yet?
• Is there any sign of early cataract, and how might that change the plan over the next few years?
• How often should I come back, and what symptoms between visits should bring me in sooner?

Two habits make the answers more useful. Write down the actual prescription numbers each time so you can track the direction of travel yourself, and ask the clinician to describe the compromise in each option in their own words, because the trade-off a fitter mentions unprompted is usually the one that matters. The NHS recommends a routine eye test every two years for most adults, sooner if advised, and that cadence is a natural rhythm for revisiting each of these questions as the eye keeps changing.

When to call your doctor

Presbyopia itself is never an emergency. The reason to take it to a professional rather than a pharmacy rack is that midlife is also when the serious, treatable eye conditions begin, and they share a symptom, blur, with the harmless one. A refraction that simply gives you readers has also, if done properly, checked the pressure inside the eye and the health of the retina and optic nerve.

Some symptoms should not wait for the next routine appointment. Seek same-day or emergency care for:

• Sudden loss of vision in one or both eyes, even if it recovers.
• A shower of new floaters, flashes of light, or a shadow or curtain moving across part of the vision, which can signal a retinal tear or detachment.
• Severe eye pain with redness, halos around lights, a headache and nausea or vomiting. This pattern can indicate acute angle-closure glaucoma, a sudden rise in eye pressure that farsighted eyes are more prone to because the front chamber is shallower, and it can damage sight within hours.
• Sudden double vision, a drooping eyelid, or vision change with weakness, numbness or difficulty speaking, which need urgent assessment for a neurological cause.
• Pain, redness or blur in a contact lens wearer, after removing the lens.

Book a prompt but non-emergency appointment if a prescription changes noticeably within months rather than years, if one eye is clearly worse than the other, if straight lines start to look wavy, if colors seem faded or if night vision deteriorates faster than daytime vision. Anyone with diabetes, a family history of glaucoma, or who takes long-term steroid medicines should tell the examiner, because those raise the odds that a blur has a second cause.

None of these signs means the worst is happening. They mean a clinician should look, and soon. The decision about what an eye needs always belongs to the team that has examined it.

Frequently asked questions

Why did I suddenly become farsighted in my 40s?

It almost certainly was not sudden. The lens has been losing flexibility for decades, and the change becomes obvious only when your nearest clear focus slips past normal reading distance. Lifelong mild hyperopia that the young lens quietly compensated for can also surface at this stage. A genuinely rapid change over days or weeks, especially in one eye, is worth reporting to an eye care professional rather than assuming it is age.

What is the difference between presbyopia vs hyperopia?

Presbyopia is age-related stiffening of the lens that removes the ability to focus up close; it affects nearly everyone from the mid-40s. Hyperopia is a structural trait, present from childhood, in which the eye is slightly too short or the cornea too flat so light focuses behind the retina. Someone can have both, and midlife is often when the second reveals the first.

What does astigmatism look like?

Astigmatism produces smearing rather than plain blur. Lights grow streaks or tails at night, letters may have a faint shadow or double edge, and lines in one direction look sharp while lines at right angles look soft. Headaches and eyestrain after long reading are common. The pattern comes from a cornea or lens curved more steeply in one direction, so light never gathers to a single point.

How bad is my astigmatism?

Read the CYL, or cylinder, value on your prescription, measured in diopters; the larger the number, the more correction your eye needs. Most adults sit in the mild range, where the effect is a soft edge rather than a limitation. More useful than the number itself is whether it has changed since your last exam, because ordinary astigmatism is usually stable in adulthood and a steadily rising value prompts a closer look at the cornea.

How can I keep astigmatism from getting worse?

For most adults there is little to prevent, because ordinary astigmatism reflects the shape you were born with and tends to stay stable. No exercise or supplement has been shown in mainstream evidence to change corneal curvature. Avoiding forceful eye rubbing is sensible for corneal health, and reporting any noticeable increase in your cylinder measurement allows a clinician to check for the rare progressive corneal condition called keratoconus.

Do I really need reading glasses after 40, or can I manage without?

Many people manage for a while by adding light and holding things farther away, and there is no harm in that. Glasses do not weaken the eyes or speed the change; they simply supply the focusing power the stiffening lens no longer provides. The reason to have a proper examination rather than relying on a rack of readers is that the same visit checks eye pressure and retinal health at the age when those problems begin.

Can farsightedness after 40 be corrected permanently?

No option restores a young, flexible lens, so presbyopia is managed rather than reversed. Surgical routes exist, including corneal laser reshaping and replacing the natural lens with a multifocal implant, and these can reduce dependence on glasses for many people, but each carries trade-offs such as reduced depth perception or halos at night. Whether any is suitable depends on corneal, lens and retinal health assessed by the treating team.

How do eye drops for presbyopia work?

They temporarily constrict the pupil, and a smaller pupil increases depth of focus in the same way a small camera aperture does. The lens itself is unchanged; the narrower beam of light simply makes near objects tolerably sharp. Effects last through much of a day. The main drawbacks are dimmer vision in low light and early brow ache, and a retinal examination is generally advised beforehand. Suitability is a decision for the prescribing clinician.

How often should I have my eyes tested after 40?

The NHS recommends a routine eye test every two years for most adults, and sooner if an eye care professional advises it. Mayo Clinic suggests a similar rhythm through the 40s and 50s, with more frequent checks later in life or if you have diabetes, a family history of glaucoma, or an existing eye condition. Any sudden change in vision should prompt an earlier appointment regardless of the schedule.

Why is farsightedness linked to angle-closure glaucoma?

Farsighted eyes are typically shorter from front to back, which leaves the front chamber shallower and the drainage angle narrower. In a small number of people the angle can close abruptly, causing eye pressure to spike. The warning pattern is severe eye pain with redness, halos around lights, headache and nausea, and it is a same-day emergency because untreated pressure can damage the optic nerve within hours.

References

• Presbyopia (MedlinePlus Medical Encyclopedia)
• Long-sightedness (NHS)
• Astigmatism (NHS)
• Presbyopia (National Eye Institute, NIH)

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.