A brand-new treatment for the most serious kind of sophisticated, dry age-related macular degeneration (AMD) has actually revealed success in an animal research study. Researchers really hope the therapy, which includes making use of a person’s very own stem cells to replace shed retina cells, will quickly be tested in human beings.
There are 2 forms of AMD:
Regarding 80% of people that have AMD of the completely dry kind, and there are numerous sorts of dry AMD, there is presently no other way to treat any kind of dry AMD.
In completely dry AMD, cells called retinal pigment epithelium (RPE) cells die. These cells support light-sensing cells in the retina called photoreceptors. When the cells die, the photoreceptors likewise eventually die. This cell death results in the most extreme form of completely dry AMD– called geographic degeneration. Geographic degeneration can bring about loss of sight.
The brand-new speculative therapy is created to change the shed cells with cells that have been developed from a client’s blood cells. In the lab, the scientists transform the person’s cells right into generated pluripotent stem cells (iPS cells). These stem cells can become any kind of cell in the body.
In this research, scientists programmed human iPS cells to end up being RPE cells. The lab-made cells were grown in tiny sheets that were one cell thick. The researchers then inserted the cells into the retinas of rats and pigs. 10 weeks after the cells were implanted, the researchers performed imaging researches that revealed the lab-made cells were incorporated within the retina.
The transplanted cells functioned effectively, the scientists reported in the journal Science Translational Medicine. These healthy and balanced brand-new cells can quit any further vision loss from completely dry AMD and also may even be able to return some shed vision.
“Having the ability to reprogram stem cells to end up being missing RPE cells is actually an interesting innovation,” claimed Pravin U. Dugel, MD, an ophthalmologist at Retinal Experts of Arizona in Phoenix, AZ.
“It’s still very early and there are a lot of difficulties still,” he stated. “Just because it operates in rats and pigs doesn’t necessarily imply it will certainly work in people. But we don’t have any kind of treatment for dry AMD, so this is something to watch out for.”.
Dr. Dugel noted that a vital concern with any stem cell therapy is that changing the nuclear framework of the cell has the potential to trigger cells to increase frantically and become malignant. The scientists claimed they genetically evaluated the RPE cells which stemmed from stem cells as well as located no genetic anomalies linked to tumour development. “Although it was not seen in this animal research study, it always remains an opportunity, which has to relapse,” Dr. Dugel said.
The researchers have started to prepare a Phase I scientific trial to examine the safety of the therapy in humans. The USA FDA should still approve the trial before it can start.
“If the clinical test moves on, it would certainly be the very first to test a stem cell-based treatment originated from generated pluripotent stem cells for dealing with an illness,” lead scientist Kapil Bharti, PhD, of the National Eye Institute stated in a press release.
Eye convulsions, Eye twitching, the twitching can last a few minutes, as well as feel like a mild tug are a common problem.
Typically taken as being safe, eyelid twitching occurs every once in a while, when there is a spontaneous convulsion of the muscles of the eyelids. It can take place both to the upper also the lower eyelids. The twitching can last a couple of mins, and also seem like a mild tug. Typically, these spasms are benign and fix on their own. However, occasionally, they could be early indications of movement disorders. Here is whatever you require to understand.
What causes them?
For some people, the convulsions are so solid, they force-shut both the eyelids. This strange problem is called ‘blepharospasm’. It goes without saying, the twitches are unpredictable and also could be triggered by: fatigue, absence of sleep, an eye irritation, physical exertion, the negative effects of a drug, tension, high levels of caffeine and/or alcohol consumption.
Whenever these convulsions became chronic in nature, their features will automatically become uncontrollable with constant winking or blinking. Blepharospasm may be made worse by the following: inflammation of the eyelid (redness), conjunctivitis, air pollution, light level of sensitivity, stress, smoking cigarettes, to name a few. With time, it can make things worse with fuzzy vision, enhanced level of sensitivity to light and facial spasms. So, get yourself inspected right away.
As discussed earlier, the twitches might be warning signs of some mind as well as nerve conditions, including face palsy, dystonia (unforeseen muscle spasms), several scleroses, Parkinson’s condition and/or Tourette syndrome.
When to go to the doctor?
If you think you have a chronic condition, you should make a visit to an eye doctor. Besides spams, if you also have the tendency and see other signs and symptoms, you must most definitely and immediately see a doctor: red, inflamed eyes with an uncommon discharge, a sagging top eyelid, if the twitching is influencing various other parts of the face, and also if it has actually been taking place for weeks on end.
If you believe you are guilty of having actually neglected your wellness earlier, attempt making amends. Get a lot of sleep, take in fewer high levels of caffeine, use a warm compress when the convulsion starts, among others.
In fact, many of us have been there before: we generally sleep with our glasses on and also awaken to find the frames bent out of shape, or a lens (otherwise both of them) is popped out of area or damaged. Or, for those who pick to use contacts, for their trip to the beach was going well until spilling amongst the waves led to a shed contact lens, making it challenging to see for the rest of our journey.
If someone has experienced any of these circumstances, one may prepare to surrender on glasses and contacts in favour of a long-term remedy to his/her vision problems– such as LASIK eye surgical treatment.
Right here are 6 frequently asked questions– and their answers– concerning LASIK.
1. How Do I Know If I’m a Candidate for LASIK Eye Surgical Procedure?
” The good news about LASIK is that it’s rather comprehensive, meaning numerous adults are qualified for this treatment,” discussed Regina H. Existing FDA authorized parameters for LASIK state that a client must have:
Approximately -12.00 D (dioptres) of near sight or myopia, also called near sightedness
Approximately +6.00 D of hyperopia, likewise called farsightedness
Up to 6 D of astigmatism (cylinder), which is a common flaw in the curvature of your eye
Prior to receiving LASIK, candidate will be needed to meet his/her optometrist for a detailed eye test. During this initial visit, the medical professional will certainly evaluate the shape and also thickness of the cornea, the dimension of pupil, as well as look for refractive mistakes such as myopia, hyperopia, astigmatism, as well as any other eye problems. The doctor might additionally inspect to see just how damp your eyes are and also may advise a precautionary treatment to decrease the risk of developing completely dry eyes after surgery.
The optimal candidate for LASIK has to:
Age should be at least 18 years.
Not have an autoimmune condition, which can make it difficult to heal after surgery.
Not be pregnant or breastfeeding. Raised hormone degrees while pregnant can affect the shape of your eyes, making it far better to wait on surgery until your hormone levels return to regular.
Have healthy eyes, including no history of cataracts, a chronic completely dry eye condition, or glaucoma.
2. Is LASIK Eye Surgical Procedure Painful?
Thankfully, LASIK eye surgery is not uncomfortable. Right prior to the procedure, surgeon will place numbing eye drops into both of the eyes. While one may still feel a little of pressure throughout the procedure, but he /she will not feel any type of discomfort.
The specialist might additionally give you another medication, such as Valium, to assist you stay calm and also sit back throughout the treatment.
After your surgery, it prevails to feel a small irritation or shedding experience in the eyes, but it must go away quickly.
3. What Does LASIK Eye Surgical Treatment Entail?
The primary goal of LASIK eye surgical procedure is to transform the shape of the cornea to ensure that it can much better focus photos onto the retina, permitting you to see more clearly. This impact is attained via the use of two lasers.
On the day of your LASIK eye surgical procedure you can expect the following:
Your doctor will certainly check your eyes to see to it your eye health history is correct.
Numbing eye drops will be put in both of the eyes and also, you’ll be offered a sedative.
Your surgeon will utilize a femtosecond laser to develop a thin, circular “flap” into cornea. The flap will certainly after that be folded back, allowing the cosmetic surgeon to access the stroma, or underlying cornea.
A laser with trendy ultraviolet beam of lights will certainly be utilized to eliminate percentages of cells from your cornea to reshape it. This allows it to extra precisely concentrate light on your retina for boosted vision.
If you are myopic, the laser will certainly be used to squash your cornea. If you are farsighted, the laser will create a steeper cornea.
The flap will certainly then be laid back in place, covering the area where the corneal tissue was eliminated.
The cornea will then be given time to heal naturally.
LASIK eye surgical treatment is a simple treatment. Though you are awake, numbing eye drops incorporated with medication will assist you stay tranquil and unbothered by the treatment. “The LASIK treatment lasts about twenty mins for both eyes,” stated Dr Altemus.
4. What Does Recovery from LASIK Involve?
After your LASIK eye surgical treatment, you will be provided a brief post-op eye examination. When your physician validates that the surgical procedure succeeded, you will certainly be allowed to go home, yet need to be driven by a family member or pal. You will certainly not be allowed to drive till after your follow-up visit with your optometrist, which will typically occur the day after your surgical treatment. At that time, she or he will certainly validate that your vision is within the legal criterion for driving.
Regarding a week after your surgery, you’ll meet your medical professional again to ensure your eyes are healing appropriately. At that visit, your doctor will determine if more follow-up visits are needed.
While you will be permitted to function the day after your treatment, it is suggested that you take a number of days off to relax.
You should additionally refrain from strenuous exercise for the week after your surgical procedure, as it can impede the healing process. You must additionally avoid putting on eye makeup for a week, as well. Once you return to using makeup, you must utilize new products to avoid the danger of infection.
Dr Altemus explained that, “Numerous prescription eye drops and man-made tears will be recommended by your doctor. These are given to assist the recovery procedure, fight bacteria as well as infection, and combat completely dry eye syndrome.”
Furthermore, she specified that, “Some people might experience a spot of blood on the white of the eye called a subconjunctival haemorrhage. This is common and also can use up to 2 weeks to heal.”
5. When Will I See well from LASIK Eye Surgery?
Instantly after your LASIK eye surgical treatment, you must start to see points from a range that you could not see before. While your eye view will likely be unclear and also hazy originally, it should maintain and remain to enhance within the very first couple of days after surgical procedure. It is not unusual for your eyes to sting a little bit or to really feel a little gritty and/or sensitive to light after your treatment.
” Individuals have actually defined their vision after LASIK, equivalent to looking under water. I generally ask patients to go home and also maintain their eyes closed for a few hrs. After 4 to 6 hrs, individuals may really feel reasonably comfortable with their vision. The majority of patients really feel really comfortable with their new vision by the next day.” Dr. Altemus additionally described, “20/20 vision is really attainable with LASIK surgery. However, this may depend on the severity of your eyesight before the treatment.”
6. Are there any Kind of Risks or Negative Effects Related to LASIK Eye Surgery?
Just like any surgery, there are some risks involved with LASIK eye surgery. Although it is rare, it may take several weeks prior to you being able to see full outcomes. You may additionally struggle with the following problems:
Impaired night-time vision, such as halos or starbursts, especially while driving
The demand for reading glasses several years after the treatment as a result of natural aging
Under or overcorrection, which would certainly need glasses or contact lenses for much better vision
Issues with the flap of corneal tissue at the time of surgical procedure
1 result found for the text you pasted (1,335 words, $0.15) on 11 Nov 2019 at 7:36 GMT. Click “Compare Text” next to a result below to see your content highlighted.
6 Common Questions About LASIK Eye Surgery – Penn Medicine … hyperopia, also called farsightedness; Up to 6 diopters of astigmatism (cylinder ), which is a common imperfection in the curvature of your eye…. and check for refractive errors such as myopia, hyperopia, astigmatism, … it better to wait for surgery until your hormone levels return to normal. … Fortunately, LASIK eye surgery is not painful. Right before your procedure, your surgeon will place numbing eye drops into both of your eyes…. Your surgeon may also give you another medication, such as Valium, to help you remain calm and relaxed during the procedure. After your … The flap will then be folded back, allowing your surgeon to access the stroma, or underlying cornea. … A laser with cool ultraviolet beams will be … Furthermore, she stated that, “Some patients may experience a spot of blood on the white of the eye called a subconjunctival hemorrhage…. there are some risks involved with LASIK eye surgery. Although it is … Complications with the flap of corneal tissue at the time of surgery.
Many of us have been there before: you fall asleep with your glasses on and wake up to find the frames bent out of shape, or a lens (if not both of them) is popped out of place or broken. Or, for those who choose to wear contacts, maybe your trip to the beach was going well until splashing among the waves resulted in a lost contact, making it difficult to see for the rest of your trip.
If you’ve experienced any of these scenarios, you may be ready to give up on glasses and contacts in favor of a permanent solution to your vision problems – such as LASIK eye surgery. Here are six frequently asked questions – and their answers – about LASIK.
1. How Do I Know If I’m a Candidate for LASIK Eye Surgery?
Up to -12.00D of myopia, also known as nearsightedness
Up to +6.00D of hyperopia, also called farsightedness
Up to 6 diopters of astigmatism (cylinder), which is a common imperfection in the curvature of your eye
Before receiving LASIK, you will be required to meet with your eye doctor for a thorough eye exam. During this initial appointment, your doctor will evaluate the shape and thickness of your cornea, the size of your pupil, and check for refractive errors such as myopia, hyperopia, astigmatism, and any other eye conditions. Your doctor may also check to see how moist your eyes are and may recommend a precautionary treatment to reduce your risk of developing dry eyes after surgery.
The ideal candidate for LASIK must:
Be at least 18 years old.
Not have an autoimmune disease, which can make it difficult to heal after surgery.
Not be pregnant or breastfeeding. Elevated hormone levels during pregnancy can affect the shape of your eyes, making it better to wait for surgery until your hormone levels return to normal.
Have healthy eyes, including no history of cataracts, a chronic dry eye condition, or glaucoma.
2. Is LASIK Eye Surgery Painful?
Fortunately, LASIK eye surgery is not painful. Right before your procedure, your surgeon will place numbing eye drops into both of your eyes. While you may still feel a little bit of pressure during the procedure, you should not feel any pain.
Your surgeon may also give you another medication, such as Valium, to help you remain calm and relaxed during the procedure.
After your surgery, it is common to feel a slight itching or burning sensation in your eyes, but it should go away quickly.
3. What Does LASIK Eye Surgery Involve?
The main goal of LASIK eye surgery is to change the shape of the cornea so that it can better focus images onto the retina, allowing you to see more clearly. This effect is achieved through the use of two lasers.
On the day of your LASIK eye surgery you can expect the following:
Your doctor will test your eyes to make sure your eye health history is correct and up to date.
Numbing eye drops will be placed in both of your eyes and you’ll be given a sedative.
Your surgeon will use a femtosecond laser to create a thin, circular “flap” in your cornea. The flap will then be folded back, allowing your surgeon to access the stroma, or underlying cornea.
A laser with cool ultraviolet beams will be used to remove small amounts of tissue from your cornea to reshape it. This enables it to more accurately focus light on your retina for improved vision.
If you are nearsighted, the laser will be used to flatten your cornea. If you are farsighted, the laser will create a steeper cornea.
The flap will then be laid back in place, covering the area where the corneal tissue was removed.
The cornea will then be given time to heal naturally.
LASIK eye surgery is a simple procedure. Though you are awake, numbing eye drops combined with medication will help you stay calm and unbothered by the procedure. “The LASIK procedure lasts approximately twenty minutes for both eyes,” said Dr. Altemus.
4. What Does Recovery from LASIK Entail?
After your LASIK eye surgery, you will be given a brief post-op eye exam. Once your doctor confirms that the surgery was successful, you will be allowed to go home, but must be driven by a family member or friend. You will not be allowed to drive until after your follow-up visit with your eye doctor, which will usually occur the day after your surgery. At that time, he or she will confirm that your vision is within the legal standard for driving.
About a week after your surgery, you’ll meet with your doctor again to make sure your eyes are healing properly. At that visit, your doctor will determine if more follow-up visits are necessary.
While you will be permitted to work the day after your procedure, it is recommended that you take a couple of days off to rest.
You should also refrain from strenuous exercise for the week after your surgery, as it can hinder the healing process. You should also avoid wearing eye makeup for a week, as well. Once you resume wearing makeup, you should use new products to avoid the risk of infection.
Dr. Altemus explained that, “Several prescription eye drops and artificial tears will be prescribed by your provider. These are given to help speed up the healing process, fight bacteria and infection, and combat dry eye syndrome.”
Furthermore, she stated that, “Some patients may experience a spot of blood on the white of the eye called a subconjunctival hemorrhage. This is common and can take up to two weeks to resolve.”
5. When Will I See Results from LASIK Eye Surgery?
Immediately after your LASIK eye surgery, you should begin to see things from a distance that you couldn’t see before. While your eye sight will likely be fuzzy and hazy initially, it should stabilize and continue to improve within the first few days after surgery. It is not uncommon for your eyes to sting a bit or to feel a little gritty and/or sensitive to light after your procedure.
“Patients have described their vision after LASIK comparable to looking under water. I usually ask patients to go home and keep their eyes closed for a few hours. After four to six hours, patients may feel relatively comfortable with their vision. Most patients feel very comfortable with their new vision by the next day.” Dr. Altemus further explained, “20/20 vision is very achievable with LASIK surgery. However, this may depend on the severity of your eyesight prior to the procedure.”
6. Are There Any Risks or Side Effects Associated with LASIK Eye Surgery?
As with any surgery, there are some risks involved with LASIK eye surgery. Although it is rare, it may take several weeks before you see full results. You may also struggle with the following issues:
Impaired night-time vision, such as seeing halos or starbursts, especially while driving
The need for reading glasses several years after the procedure due to natural aging
Under or overcorrection, which would require glasses or contact lenses for better vision
Complications with the flap of corneal tissue at the time of surgery
Are you considering LASIK eye surgery? To learn more about this procedure and determine if you are a candidate, schedule an appointment with a Penn Medicine provider online.
IMPACT OF INCREASING PREVALENCEOF MYOPIA AND HIGH MYOPIA.
The occurrence of myopia and high myopia are increasing globally at an alarming rate, with substantial increases in the risks for vision impairment from pathologic conditions associated with high myopia, including retinal damage, cataract and glaucoma. The impact of myopia is challenging to identify, due to the fact that there are no standard definitions of myopia and high myopia, and recognition that myopia can lead to vision impairment which is limited by the absence of a specified category of myopic retinal disease that triggers long-term vision impairment. An additional impediment to progress in this area is insufficient evidence of the efficacy of various methods for managing myopia.
The epidemiological surveys presently used to determine the status of vision (e.g. the World Health Organisation’s protocol and Fast Assessment of Avoidable Blindness) do not permit the interpretation of high myopia as a possible cause of vision impairment, partially because these studies do not include a description of this condition or any type of measurement of refractive error. The group concurred that action ought to be taken to include myopia and high myopia among the attributable reasons for vision impairment disability in the surveys presently used.
Measures for the detection and management of myopia ought to be an integral part of plans for the provision of eye-care services. They ought to be part of general health care for vision impairment due to
(i) the uncorrected refractive error associated with related to the increased prevalence of myopia;
(ii) the pathologic repercussions of myopia.
The term “myopic macular degeneration” (MMD) should be used scientifically and in research to classify the blinding retinal diseases associated with high myopia. Presently, a number of terms are used, including MMD, myopic maculopathy, myopic retinopathy and myopic choroidal neovascularization.
Epidemiological data are lacking on the occurrence of myopia, high near-sightedness and vision impairment connected with high myopia in Africa, Central America, South America and Oceania. These locations ought to be priorities for future research study.
Interpretations of myopia and high myopia
The medicinal definition of myopia is “a condition in which the spherical equivalent objective refractive error is ≤– 0.50 diopter (– 0.50 D) in either eye”.
Medical definition of myopic macular degeneration.
The scientific definition of myopic macular degeneration (MMD) is “a vision-threatening condition in individuals with near-sightedness, usually high myopia, which comprises diffuse, patchy macular atrophy with or without lacquer cracks, choroidal neovascularization and Fuchs spot”.
It was concurred that the straight ophthalmoscope lens power wheel should be used in fast assessments of avoidable blindness and other surveys to record the power at which the fundus is clearest, to ensure that possible cases of high myopia are recorded.
In fact, the access to correction for myopia is essential to avoid vision impairment. All people with myopia ought to have accessibility to appropriate, precise refractive correction.
Although there is an extensively held clinical view that under correction of myopia is beneficial in preventing its development, the available proof does not support this concept. Recent reports show that under correction is associated with a higher rate of progression of myopia.
Some preliminary released evidence indicates that time invested outdoors can delay the onset and possibly reduce the development of myopia, although even more research study is required, as it is likewise potentially a risk factor. If the proof is confirmed appropriate, it will certainly include advantageous eye care to the listing of other health-promoting outdoor activities e.g. reduction of childhood obesity through workout, direct exposure to sunlight for vitamin D manufacturing, ready socialization.
There is a published evidence that, excessive near work increases the risk of myopia.
There is published evidence that multifocal spectacles can slightly reduce the rate of development of myopia; executive bifocal lenses are associated with substantially bigger reductions.
Specially designed contact lenses that minimize peripheral hyperopia and/or create significant myopic defocus can slow down the progress of myopia. It is essential that contact lenses can slow down the progress of myopia, but overnight wear of contact lenses is related to risks.
WHAT IS TECNIS MULTIFOCAL LENS? The TECNIS ® Multifocal 1-Piece intraocular lenses are prescribed for primary implantation for the visual correction of aphakia in grown-up patients with and without presbyopia in whom a cataractous lens has actually been removed by phacoemulsification and also that prefer near, intermediate, as well as distance vision with increased freedom from spectacles. These intraocular lenses are meant to be placed in the capsular bag.
Tecnis Multifocal IOL OUTSTANDING, FULL-RANGE VISION TAILORED FOR LONGER READING TECNIS ® Multifocal 1-Piece IOLs have been made available in 3 options so you can provide your patients with outcomes which provide spectacle independence distinctly matched to their visual lifestyles. The TECNIS ® Multifocal IOL +3.25 D delivers a complete variety of the sharpest vision tailored for longer reading distances. Recommended IOL Insertion: The TECNIS ® Multifocal IOL +3.25 D is developed with your patients in mind. Optimized for those favoring activities at longer reading ranges such as multimedia work, it provides tailored clarity at a theoretical reading distance of 42 centimeters.
SHARPEST VISION ALL DISTANCES The TECNIS ® Multifocal Family of 1-Piece IOLs features the only multifocal lenses efficient in offering a complete range of high-quality vision (20/25 or much better) tailored for every patient lifestyle:
• The sharpest vision across near, intermediate as well as distance vision. • Optimized for a theoretical analysis distance of 33 centimeters with the +4.0 D lens.
When contrasted to various other leading multifocal IOLs, TECNIS ® Multifocal IOLs provide: • Approximately 4x higher image comparison at near distance in low light 5 mm pupil. • 2x higher image contrast at near distance in normal light 3 mm pupil.
ENHANCED FUNCTIONALITY Give your patients a lens developed for real-world performance. The TECNIS ® Multifocal IOL +4.0 D delivers enhanced, customized spectacle independence.
LONG-TERM SUSTAINABILITY Unlike an additional leading IOL, TECNIS ® IOL product is not connected with glistenings, which can inhibit your patient’s vision. glistenings cause light scatter, which can result in a reduction in image contrast.
Myopia causes: Is your child at risk? Moms and dads – specifically those that are myopic and also put on glasses throughout childhood years – typically are worried regarding the reasons for near-sightedness as well as whether their kids are destined to being myopic, as well.
If this seems like you, attempt not to fret way too much. Near-sightedness is a typical refractive error. It’s conveniently treatable with spectacles or contact lenses (as well as LASIK or other vision surgical treatments, as soon as your youngster comes to be a young adult), and also, it’s not purely genetic.
Additionally, near-sightedness commonly does not impact a kid’s scholastic efficiency or hold them back at all. As a matter of fact, there’s proof that myopic kids have a tendency to carry out far better in school than their equivalents with typical vision, farsightedness or astigmatism.
What triggers near-sightedness in youngsters? Although the precise reason that some kids end up being myopic and also others do not is not completely comprehended, though it shows up genetics is an aspect, yet not the only one.
Women with blue eyes, those that are book lovers are most likely to be myopic than various other kids? Some scientists and optometrists believe so, however the evidence is not well-defined.
To put it simply, if both moms and dads are myopic, there is a higher risk their kids will certainly be myopic, too. However, you can’t anticipate who will become myopic by merely looking at their family history.
Some scientists believe focusing exhaustion from excessive analysis or holding a book or digital display near your eyes for prolonged durations can enhance the risk for myopia in kids. But no one knows without a doubt. The precise reason or causes of myopia may remain a mystery, however scientists recently have actually discovered something about the development of near-sightedness that is extremely intriguing: regular glasses and contact lenses that have been recommended for many years to fix myopia might in fact enhance the risk of myopia getting worse throughout childhood!
Most of these same researchers are examining brand-new lens designs to see if they can find eyeglasses or contact lenses that can halt or slow down the development of near-sightedness in kids.
Just how to reduce your kid’s risk of myopia
This may seem artful, however maybe one of the very best things to inform your kid to decrease his/her risk of near-sightedness is, “Go outdoors and play!”
A variety of recent researchers have discovered that investing more time outdoors may help avoid or minimize the progression of near-sightedness in kids.