Math Is Fun Forum

2451) John Franklin Enders

Gist:

Work

Many infectious diseases are caused by viruses—very small biological particles. A virus lacks metabolism of its own and cannot multiply without infecting a living cell. For a long time the prevailing opinion was that viruses could not be cultured in a laboratory. However, in 1949 John Enders, Frederick Robbins, and Thomas Weller succeeded in culturing the virus that causes polio in human muscle and tissue in a laboratory setting. This became an important step on the road toward a vaccine against polio.

Summary

John Franklin Enders (born Feb. 10, 1897, West Hartford, Conn., U.S.—died Sept. 8, 1985, Waterford, Conn.) was an American virologist and microbiologist who, with Frederick C. Robbins and Thomas H. Weller, was awarded the Nobel Prize for Physiology or Medicine for 1954 for his part in cultivating the poliomyelitis virus in nonnervous-tissue cultures, a preliminary step to the development of the polio vaccine.

Enders was a student of English literature at Harvard University (M.A., 1922) before he turned to bacterial studies there (Ph.D., 1930). His early researches contributed new and basic knowledge to problems of tuberculosis, pneumococcal infections, and resistance to bacterial diseases. In 1929 he joined the Harvard faculty as an assistant in the department of bacteriology and immunology, later advancing to assistant professor (1935) and associate professor (1942) in the university’s medical school.

In World War II he was a civilian consultant on infectious diseases to the U.S. War Department. From 1945 to 1949 he served the U.S. Army in a like capacity, with particular work on the mumps virus and rickettsial diseases. During this period Enders, with his coworkers Weller and Robbins, began research into new methods of producing in quantity the virus of poliomyelitis. Until that time the only effective method of growing the virus had been in the nerve tissue of living monkeys, and the vaccine thus produced had been proved dangerous to humans. The Enders–Weller–Robbins method of production, achieved in test tubes using cultures of nonnerve tissue from human embryos and monkeys, led to the development of the Salk vaccine for polio in 1954. Similarly, their production in the late 1950s of a vaccine against the measles led to the development of a licensed vaccine in the United States in 1963. Much of Enders’ research on viruses was conducted at the Children’s Hospital in Boston, where he had established a laboratory in 1946.

Details

John Franklin Enders (February 10, 1897 – September 8, 1985) was an American biomedical scientist and Nobel Laureate. Enders has been called "The Father of Modern Vaccines."

Life and education

Enders was born in West Hartford, Connecticut on February 10, 1897. His father, John Ostrom Enders, was CEO of the Hartford National Bank and left him a fortune of $19 million upon his death. He attended the Noah Webster School in Hartford, and graduated from St. Paul's School in Concord, New Hampshire in 1915. After attending Yale University a short time, he joined the United States Army Air Corps in 1918 as a flight instructor and a lieutenant.

After returning from World War I, he graduated from Yale, where he was a member of Scroll and Key as well as Delta Kappa Epsilon. He went into real estate in 1922, and tried several careers before choosing the biomedical field with a focus on infectious diseases, gaining a PhD at Harvard in 1930. He later joined the faculty at Children's Hospital Boston.

Enders died at his summer home in Waterford, Connecticut, aged 88, on 8 September 1985. His wife died in 2000.

Biomedical career

In 1949, Enders, Thomas Huckle Weller, and Frederick Chapman Robbins reported successful in vitro culture of an animal virus—poliovirus. The three received the 1954 Nobel Prize in Physiology or Medicine "for their discovery of the ability of poliomyelitis viruses to grow in cultures of various types of tissue".

Meanwhile, Jonas Salk applied the Enders-Weller-Robbins technique to produce large quantities of poliovirus, and then developed a polio vaccine in 1952. Upon the 1954 polio vaccine field trial, whose success Salk announced on the radio, Salk became a public hero but failed to credit the many other researchers that his effort rode upon, and was somewhat shunned by America's scientific establishment.

In 1954, Enders and Thomas C. Peebles isolated measlesvirus from an 11-year-old boy, David Edmonston. Disappointed by polio vaccine's development and involvement in some cases of polio and death—what Enders attributed to Salk's technique—Enders began development of measles vaccine. In October 1960, an Enders team began trials on 1,500 intellectually disabled children in New York City and on 4,000 children in Nigeria. Refusing credit for merely himself when The New York Times announced the measles vaccine effective on September 17, 1961, Enders wrote to the newspaper to acknowledge the work of various colleagues and the collaborative nature of the research. In 1963, a deactivated measles vaccine and an attenuated measles vaccine were introduced by Pfizer and Merck & Co., respectively.

He continued to work in virology research till the late 1970s and retired from the laboratory at the age of 80.

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#2587. What does the medical term Coombs test signify?

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#6366.

2450) Linus Pauling

Gist:

Life

Linus Pauling was born in Portland, Oregon, in the United States. His family came from a line of Prussian farmers, and Pauling's father worked as a pharmaceuticals salesman, among other things. After first studying at Oregon State University in Corvallis, Oregon, Pauling earned his PhD from the California Institute of Technology in Pasadena, with which he maintained ties for the rest of his career. In the 1950s, Pauling's involvement in the anti-nuclear movement led to his being labeled a suspected communist, which resulted in his passport being revoked at times. Linus and Ava Helen Pauling had four children together.

Work

The development of quantum mechanics during the 1920s had a great impact not only on the field of physics, but also on chemistry. During the 1930s Linus Pauling was among the pioneers who used quantum mechanics to understand and describe chemical bonding–that is, the way atoms join together to form molecules. Pauling worked in a broad range of areas within chemistry. For example, he worked on the structures of biologically important chemical compounds. In 1951 he published the structure of the alpha helix, which is an important basic component of many proteins.

Summary

Linus Carl Pauling (February 28, 1901 – August 19, 1994) was an American chemist and peace activist. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. New Scientist called him one of the 20 greatest scientists of all time. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of five people to have won more than one Nobel Prize. Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields, the other being Marie Skłodowska-Curie.

Pauling was one of the founders of the fields of quantum chemistry and molecular biology. His contributions to the theory of the chemical bond include the concept of orbital hybridisation and the first accurate scale of electronegativities of the elements. Pauling also worked on the structures of biological molecules, and showed the importance of the alpha helix and beta sheet in protein secondary structure. Pauling's approach combined methods and results from X-ray crystallography, molecular model building, and quantum chemistry. His discoveries inspired the work of James Watson, Francis Crick, Rosalind Franklin, and Maurice Wilkins on the structure of DNA, which in turn made it possible for geneticists to crack the DNA code of all organisms.

In his later years, he promoted nuclear disarmament, as well as orthomolecular medicine, megavitamin therapy, and dietary supplements, especially ascorbic acid (commonly known as Vitamin C). None of his ideas concerning the medical usefulness of large doses of vitamins have gained much acceptance in the mainstream scientific community. He was married to the American human rights activist Ava Helen Pauling.

Details

Linus Pauling (born February 28, 1901, Portland, Oregon, U.S.—died August 19, 1994, Big Sur, California) was an American theoretical physical chemist who became the only person to have won two unshared Nobel Prizes. His first prize (1954) was awarded for research into the nature of the chemical bond and its use in elucidating molecular structure; the second (1962) recognized his efforts to ban the testing of nuclear weapons.

Early life and education

Pauling was the first of three children and the only son of Herman Pauling, a pharmacist, and Lucy Isabelle (Darling) Pauling, a pharmacist’s daughter. After his early education in Condon and Portland, Oregon, he attended Oregon Agricultural College (now Oregon State University), where he met Ava Helen Miller, who would later become his wife, and where he received his Bachelor of Science degree in chemical engineering summa cum laude in 1922. He then attended the California Institute of Technology (Caltech), where Roscoe G. Dickinson showed him how to determine the structures of crystals using X rays. He received his Ph.D. in 1925 for a dissertation derived from his crystal-structure papers. Following a brief period as a National Research Fellow, he received a Guggenheim Fellowship to study quantum mechanics in Europe. He spent most of the 18 months at Arnold Sommerfeld’s Institute for Theoretical Physics in Munich, Germany.

Elucidation of molecular structures

After completing postdoctoral studies, Pauling returned to Caltech in 1927. There he began a long career of teaching and research. Analyzing chemical structure became the central theme of his scientific work. By using the technique of X-ray diffraction, he determined the three-dimensional arrangement of atoms in several important silicate and sulfide minerals. In 1930, during a trip to Germany, Pauling learned about electron diffraction, and upon his return to California he used this technique of scattering electrons from the nuclei of molecules to determine the structures of some important substances. This structural knowledge assisted him in developing an electronegativity scale in which he assigned a number representing a particular atom’s power of attracting electrons in a covalent bond.

To complement the experimental tool that X-ray analysis provided for exploring molecular structure, Pauling turned to quantum mechanics as a theoretical tool. For example, he used quantum mechanics to determine the equivalent strength in each of the four bonds surrounding the carbon atom. He developed a valence bond theory in which he proposed that a molecule could be described by an intermediate structure that was a resonance combination (or hybrid) of other structures. His book The Nature of the Chemical Bond, and the Structure of Molecules and Crystals (1939) provided a unified summary of his vision of structural chemistry.

The arrival of the geneticist Thomas Hunt Morgan at Caltech in the late 1920s stimulated Pauling’s interest in biological molecules, and by the mid-1930s he was performing successful magnetic studies on the protein hemoglobin. He developed further interests in protein and, together with biochemist Alfred Mirsky, Pauling published a paper in 1936 on general protein structure. In this work the authors explained that protein molecules naturally coiled into specific configurations but became “denatured” (uncoiled) and assumed some random form once certain weak bonds were broken.

On one of his trips to visit Mirsky in New York, Pauling met Karl Landsteiner, the discoverer of blood types, who became his guide into the field of immunochemistry. Pauling was fascinated by the specificity of antibody-antigen reactions, and he later developed a theory that accounted for this specificity through a unique folding of the antibody’s polypeptide chain. World War II interrupted this theoretical work, and Pauling’s focus shifted to more practical problems, including the preparation of an artificial substitute for blood serum useful to wounded soldiers and an oxygen detector useful in submarines and airplanes. J. Robert Oppenheimer asked Pauling to head the chemistry section of the Manhattan Project, but his suffering from glomerulonephritis (inflammation of the glomerular region of the kidney) prevented him from accepting this offer. For his outstanding services during the war, Pauling was later awarded the Presidential Medal for Merit.

While collaborating on a report about postwar American science, Pauling became interested in the study of sickle-cell anemia. He perceived that the sickling of cells noted in this disease might be caused by a genetic mutation in the globin portion of the blood cell’s hemoglobin. In 1949 he and his coworkers published a paper identifying the particular defect in hemoglobin’s structure that was responsible for sickle-cell anemia, which thereby made this disorder the first “molecular disease” to be discovered. At that time, Pauling’s article on the periodic law appeared in the 14th edition of Encyclopædia Britannica.

While serving as a visiting professor at the University of Oxford in 1948, Pauling returned to a problem that had intrigued him in the late 1930s—the three-dimensional structure of proteins. By folding a paper on which he had drawn a chain of linked amino acids, he discovered a cylindrical coil-like configuration, later called the alpha helix. The most significant aspect of Pauling’s structure was its determination of the number of amino acids per turn of the helix. During this same period he became interested in deoxyribonucleic acid (DNA), and early in 1953 he and protein crystallographer Robert Corey published their version of DNA’s structure, three strands twisted around each other in ropelike fashion. Shortly thereafter James Watson and Francis Crick published DNA’s correct structure, a double helix. Pauling’s efforts to modify his postulated structure had been hampered by poor X-ray photographs of DNA and by his lack of understanding of this molecule’s wet and dry forms. In 1952 he failed to visit Rosalind Franklin, working in Maurice Wilkins’s laboratory at King’s College, London, and consequently did not see her X-ray pictures of DNA. Frankin’s pictures proved to be the linchpin in allowing Watson and Crick to elucidate the actual structure. Nevertheless, Pauling was awarded the 1954 Nobel Prize for Chemistry “for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances.”

Humanitarian activities of Linus Pauling

During the 1950s Pauling and his wife became well known to the public through their crusade to stop the atmospheric testing of nuclear weapons. In 1958 they presented an appeal for a test ban to the United Nations in the form of a document signed by 9,235 scientists from 44 countries. Pauling’s sentiments were also promulgated through his book No More War! (1958), a passionate analysis of the implications of nuclear war for humanity. In 1960 he was called upon to defend his actions regarding a test ban before a congressional subcommittee. By refusing to reveal the names of those who had helped him collect signatures, he risked going to jail—a stand initially condemned but later widely admired. His work on behalf of world peace was recognized with the 1962 Nobel Prize for Peace awarded on October 10, 1963, the date that the Nuclear Test Ban Treaty went into effect.

Pauling’s Peace Prize generated such antagonism from Caltech administrators that he left the institute in 1963. He became a staff member at the Center for the Study of Democratic Institutions in Santa Barbara, California, where his humanitarian work was encouraged. Although he was able to develop a new model of the atomic nucleus while working at the Center, his desire to perform more experimental research led him to a research professorship at the University of California in San Diego in 1967. There he published a paper on orthomolecular psychiatry that explained how mental health could be achieved by manipulating substances normally present in the body. Two years later he accepted a post at Stanford University, where he worked until 1972.

Later years

While at San Diego and Stanford, Pauling’s scientific interests centred on a particular molecule—ascorbic acid (vitamin C). He examined the published reports about this vitamin and concluded that, when taken in large enough quantities (megadoses), it would help the body fight off colds and other diseases. The outcome of his research was the book Vitamin C and the Common Cold (1970), which became a best-seller. Pauling’s interest in vitamin C in particular and orthomolecular medicine in general led, in 1973, to his founding an institute that eventually bore his name—the Linus Pauling Institute of Science and Medicine. During his tenure at this institute, he became embroiled in controversies about the relative benefits and risks of ingesting megadoses of various vitamins. The controversy intensified when he advocated vitamin C’s usefulness in the treatment of cancer. Pauling and his collaborator, the Scottish physician Ewan Cameron, published their views in Cancer and Vitamin C (1979). Their ideas were subjected to experimental animal studies funded by the institute. While these studies supported their ideas, investigations at the Mayo Clinic involving human cancer patients did not corroborate Pauling’s results.

Although he continued to receive recognition for his earlier accomplishments, Pauling’s later work provoked considerable skepticism and controversy. His cluster model of the atomic nucleus was rejected by physicists, his interpretation of the newly discovered quasicrystals received little support, and his ideas on vitamin C were rejected by the medical establishment. In an effort to raise money to support his increasingly troubled institute, Pauling published How to Live Longer and Feel Better (1986), but the book failed to become the success that he and his associates had anticipated.

Both Pauling and his wife developed cancer. Ava Helen Pauling died of stomach cancer in 1981. Ten years later Pauling discovered that he had prostate cancer. Although he underwent surgery and other treatments, the cancer eventually spread to his liver. He died at his ranch on the Big Sur coast of California.

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#6365.

2512) Intraocular Lens

Gist

Intraocular lenses (IOLs) are tiny, artificial, permanent lenses implanted inside the eye to replace a natural lens removed during cataract surgery or to correct refractive errors like myopia, hyperopia, and astigmatism. Made of acrylic or silicone, they restore clear vision by focusing light on the retina without needing maintenance.

Intraocular lenses usually last a lifetime. How is an intraocular lens used in cataract surgery? Cataract surgery involves removing the eye's natural lens which has become cloudy (cataract) and replacing it with an intraocular lens.

Summary

An intraocular lens (or IOL) is a tiny, artificial lens for the eye. It replaces the eye's natural lens that is removed during cataract surgery.

The lens bends (refracts) light rays that enter the eye, helping you to see. Your lens should be clear. But if you have a cataract, your lens has become cloudy. Things look blurry, hazy or less colorful with a cataract. Cataract surgery removes this cloudy lens and replaces it with a clear IOL to improve your vision.

IOLs come in different focusing powers, just like prescription eyeglasses or contact lenses. Your ophthalmologist will measure the length of your eye and the curve of your cornea. These measurements are used to set your IOLs focusing power.

What are IOLs made of?

Most IOLs are made of silicone, acrylic, or other plastic compositions. They are also coated with a special material to help protect your eyes from the sun's harmful ultraviolet (UV) rays.

Monofocal IOLs

The most common type of lens used with cataract surgery is called a monofocal IOL. It has one focusing distance. It is set to focus for up close, medium range or distance vision. Most people have them set for clear distance vision. Then they wear eyeglasses for reading or close work.

Some IOLs have different focusing powers within the same lens. These are called presbyopia-correcting IOLs. These IOLs reduce your dependence on glasses by giving you clear vision for more than one set distance.

Multifocal IOLs

These IOLs provide both distance and near focus at the same time. The lens has different zones set at different powers.

Extended depth-of-focus IOLs:

Similar to multifocal lenses, extended depth-of-focus (EDOF) lenses sharpen near and far vision, but with only one corrective zone, which “extends” to cover both distances. This may mean less effort to re-focus between distances.

Accommodative IOLs

These lenses move or change shape inside your eye, allowing focusing at different distances.

Toric IOLs

For people with astigmatism, there is an IOL called a toric lens. Astigmatism is a refractive error caused by an uneven curve in your cornea or lens. The toric lens is designed to correct that refractive error.

Details

An intraocular lens (IOL) is a lens implanted in the eye usually as part of a treatment for cataracts or for correcting other vision problems such as near-sightedness (myopia) and far-sightedness (hyperopia); a form of refractive surgery. If the natural lens is left in the eye, the IOL is known as phakic, otherwise it is a pseudophakic lens (or false lens). Both kinds of IOLs are designed to provide the same light-focusing function as the natural crystalline lens. This can be an alternative to LASIK, but LASIK is not an alternative to an IOL for treatment of cataracts.

IOLs usually consist of a small plastic lens with plastic side struts, called haptics, to hold the lens in place in the capsular bag inside the eye. IOLs were originally made of a rigid material (PMMA), although this has largely been superseded by the use of flexible materials, such as silicone. Most IOLs fitted today are fixed monofocal lenses matched to distance vision. However, other types are available, such as a multifocal intraocular lens that provides multiple-focused vision at far and reading distance, and adaptive IOLs that provide limited visual accommodation. Multifocal IOLs can also be trifocal IOLs or extended depth of focus (EDOF) lenses.

As of 2021, nearly 28 million cataract procedures took place annually worldwide. That is about 75,000 procedures per day globally. The procedure can be done under local or topical anesthesia with the patient awake throughout the operation. The use of a flexible IOL enables the lens to be rolled for insertion into the capsular bag through a very small incision, thus avoiding the need for stitches. This procedure usually takes less than 30 minutes in the hands of an experienced ophthalmologist, and the recovery period is about two to three weeks. After surgery, patients should avoid strenuous exercise or anything else that significantly increases blood pressure. They should visit their ophthalmologists regularly for three weeks to monitor the implants.

IOL implantation carries several risks associated with eye surgeries, such as infection, loosening of the lens, lens rotation, inflammation, nighttime halos and retinal detachment. Though IOLs enable many patients to have reduced dependence on glasses, most patients still rely on glasses for certain activities, such as reading. These reading glasses may be avoided in some cases if multifocal IOLs, trifocal IOLs or EDOF lenses are used.

Additional Information

IOLs (intraocular lenses) are clear, artificial lenses that replace your eye’s natural ones. You receive IOLs during cataract surgery and refractive lens exchange. IOL implants correct a range of vision issues, including nearsightedness and age-related farsightedness. They may also help reduce your reliance on glasses for certain types of tasks.

What are IOLs?

IOLs (intraocular lenses) are clear artificial lenses that a healthcare provider will implant in your eye to replace your natural lens. Like glasses or contacts, IOL implants can correct vision issues such as:

* Myopia (nearsightedness).
* Hyperopia (farsightedness).
* Presbyopia (age-related farsightedness).
* Astigmatism (altered eye shape).

IOL implants are permanent, meaning they stay in your eyes for the rest of your life. IOLs help improve your vision and may reduce your reliance on glasses in your daily routine. You receive IOLs during eye lens replacement surgery, most commonly during cataract surgery.

Who needs intraocular lens implants?

You may benefit from IOL implants if you:

* Have cataracts that prevent you from seeing clearly. Virtually everyone undergoing cataract surgery will need to have an IOL implant in order to restore vision.
* Have refractive errors that affect your vision, but you’re not a candidate for LASIK or other vision correction surgeries.

What are the different types of intraocular lenses?

There are many types of IOLs, each with its own pros and cons. The main drawback with some types of IOLs is you’ll still need to wear glasses for some tasks (like reading). Some IOLs can reduce your reliance on glasses, but you may notice side effects like glare around lights at night.

The list below covers some general categories of IOLs. Ask your ophthalmologist about which type of IOL is best for you. They’ll help you customize your IOL selection to suit your vision needs, lifestyle and personal preferences.

Monofocal lenses

This is the type of IOL that most people select. Monofocal lenses have one focusing power. This means they sharpen either your distance, mid-range or close-up vision. Most people set their monofocal lenses for distance vision, which can help with tasks like driving. You’ll probably still need glasses for close-up vision.

Monofocal lenses with monovision

Monofocal IOLs set to monovision are a good option for some people who want to rely less on glasses. Normally, the monofocal IOLs for both of your eyes are set to the same range (like distance). But with monovision, the lens for each eye has a different focusing power. For example, the lens for your right eye might correct for distance, with the lens for your left eye correcting for close-up vision.

With monovision, your eyes work together to help you see both distant and close-up objects. One drawback is that it takes some time to adapt to monovision. Some people can’t adapt to monovision at all. So, before choosing monovision IOLs, your provider may suggest you try monovision contact lenses for a couple of weeks. This allows you to see if this method of correction feels comfortable to you.

Multifocal lenses

Multifocal lenses improve your close-up and distance vision and may reduce your need for glasses. Unlike monofocal lenses, multifocal lenses contain several focal zones. Your brain adjusts to these zones and chooses the focusing power you need for any given task (like driving or reading). You may need some time to adapt to these lenses. But over time, you should be able to rely less on your reading glasses. Some people don’t need glasses at all.

One drawback of multifocal lenses is that you may notice rings or halos around lights, like when driving at night.

Extended depth-of-focus (EDOF) lenses

Unlike multifocal lenses, EDOF lenses contain one long focal point that expands your corrected range of vision and depth of focus. These lenses give you excellent distance vision along with improvements in your mid-range vision (for tasks such as computer use). You may still need to use glasses for close-up tasks like reading.

Accommodative lenses

These lenses are similar to your eyes’ natural lenses in that they adjust their shape to help you see close-up or distant objects. Accommodative lenses are another option to help reduce dependency on glasses. But you may prefer to use glasses if you’re reading or focusing on close-up objects for longer periods of time.

Toric lenses

Toric lenses help people who have astigmatism. These lenses improve how light hits your retina, allowing you to have a sharper, clearer vision. Toric lenses are available in monofocal, multifocal, extended depth of focus (EDOF) or accommodative models. They serve to improve the quality of the vision delivered. Toric lenses will help reduce the amount of glare and halos artifacts commonly experienced by people with astigmatism.

Light-adjustable lenses (LALs)

Light-adjustable lenses are different from other IOL options in that your ophthalmologist fine-tunes their corrective power after your lens replacement surgery. They do this through a series of UV light treatment procedures, spaced several days apart. These procedures customize your lens prescription to bring you as close to your desired visual outcome as possible. This is still a type of monofocal lens, so glasses will be necessary for reading or driving.

Phakic lenses

Phakic lenses are typically implanted in younger individuals while trying to preserve the natural human lens, to correct for near-sightedness in people who don’t qualify for laser refractive surgery. This helps preserve your natural ability to focus and accommodate. These lenses will eventually have to be removed during cataract surgery but can offer younger people clear vision for a long time.

Which intraocular lens is best for me?

Your ophthalmologist will determine if you would benefit from cataract surgery, or if you would qualify for a refractive lens exchange surgery. They’ll discuss your options and help you decide which IOLs are best for you. They’ll also conduct a thorough eye exam to check your vision and the health of your eyes. They’ll perform some simple, painless tests to measure your eye size and shape, too.

To prepare for a conversation with your ophthalmologist, you should think about your priorities for your IOLs, as well as aspects that aren’t as important to you. It may help to ask yourself the following questions:

* Am I OK wearing glasses sometimes? If so, how often and for what types of tasks?
* What kind of vision is required in my work/profession? Am I OK wearing glasses for these tasks?
* Do I drive often at night? If so, can I adapt to seeing glare and halos around lights when I drive?
* What kind of hobbies and activities do I enjoy the most and how much dependency on glasses am I OK with for these activities?
* What is my budget for surgery?

Most insurance plans cover monofocal lenses, but you may have to pay for other types out of pocket. Be sure to find out the cost of various IOL options before making your final decision.

What are possible issues and complications related to IOL implantation?

Most IOL complications are rare and include:

* Posterior capsular opacification:This is commonly known as a secondary cataract. This happens after many months or years when a film-like material grows behind the implanted lens. This is a normal process that happens after surgery and can be expected to occur over time for almost everyone. The treatment for this is very quick and straightforward and is usually performed using a laser in the office.
* IOL dislocation: This means your IOL shifts from its normal position. You face a higher risk if you have certain eye conditions, like pseudoexfoliation syndrome, or have had trauma or prior eye surgeries. Certain genetic disorders, such as Ehlers-Danlos syndrome and Marfan syndrome, may also raise your risk. In some cases, you may need surgery to reposition or replace the IOL.
* Uveitis-glaucoma-hyphema (UGH) syndrome: UGH syndrome occurs when an IOL irritates your iris and other parts of your eye. This leads to inflammation, raised intraocular pressure and other symptoms. As with IOL dislocation, you may need surgery to reposition or replace the IOL. This is an extremely rare complication that most people don’t experience with routine surgery.
* IOL opacification: This is a clouding of your IOL. Your vision may become less sharp, and you may notice glare around lights. Treatment involves surgery to give you a new IOL. This is extremely uncommon with modern-day IOLs.
* Refractive surprise: A refractive surprise is when your vision after IOL implantation isn’t as sharp as you and your ophthalmologist expected. Your ophthalmologist will suggest a range of solutions. You may decide to accept the vision correction as is and do nothing further. Or you can choose to wear glasses, have laser vision correction (such as LASIK or PRK) or have an IOL replacement surgery.

Talk with your ophthalmologist about possible complications and your level of risk before choosing to have IOLs implanted in your eyes. They’ll tell you what to expect based on your medical history, eye health and other factors. Also, ask them about common side effects associated with cataract surgery or refractive lens exchange. Be sure to get all the information you need to make the decision that’s right for you.

LASIK

LASIK is a laser eye surgery that corrects vision problems. It changes the shape of your cornea to improve how light hits your retina. This improves your vision. About 99% of people have uncorrected vision that’s 20/40 or better after their LASIK surgery. More than 90% end up with 20/20 vision. Dry eye is the most common side effect.

PRK

Photorefractive keratectomy (PRK) is a laser eye surgery similar to LASIK. Unlike LASIK, which involves opening a flap in your cornea, PRK removes your cornea so that it grows back naturally. That makes it a better laser eye surgery choice for some people who can’t undergo LASIK.