Penny Pusher Game Shows How Cataracts May Form
March 2015 In a penny pusher arcade game, the player drops a coin on a moving platform that contains other coins. Coins fall off the edge of the platform onto a lower one, and if the player timed his drop correctly, then coins eventually accumulate where the player can collect them.
Researchers studied mouse eyes for nearly four years to see how their lens cells grow and found similarities to the penny pusher game.
The cells tended to multiply in a narrow line on the lens surface, pushing neighboring cells toward the equator of the lens. Cells already at the equator were pushed away from the surface, into the center of the lens.
Since the penny pusher-style cell movement is relatively orderly, the eye maintains its shape over time, for consistent vision.
Cataracts (lens cloudiness) may start as mutations in a few cells, and the penny pusher model may explain the growth of the cataract over time.
"We are currently examining whether mutations in the DNA of individual lens cells can be transmitted to large numbers of lens cells, potentially influencing the clarity of the tissue and resulting in cataract," said Steven Bassnett, PhD, of Washington University School of Medicine, Department of Ophthalmology and Visual Sciences.
A full report of this study appears in the latest issue of Investigative Ophthalmology & Visual Science .
New DNA Test Quickly Diagnoses Cause of Congenital Cataracts
October 2014 An advanced test that quickly identifies the different DNA mutations that can cause congenital cataracts in children has been developed.
Prior to this DNA test, doctors diagnosed the rare diseases that result in congenital cataracts through extensive family health reports and numerous costly clinical assessments that were often inconclusive.
Using "next-generation" DNA sequencing, researchers at the University of Manchester, in collaboration with Manchester Royal Eye Hospital, were able to diagnose the exact genetic cause of congenital cataracts in 75 percent of the cases in only a few weeks. Because congenital cataracts can appear as a symptom of hundreds of rare diseases, be inherited, or arise from a maternal infection, knowing the exact cause helps doctors tailor care and begin treatment or counseling right away.
Currently the test is available in the U.K., but registered facilities can request it through international referral, according to the American Academy of Ophthalmology.
A full report of this study appears in the September issue of Ophthalmology.
Is It Worth It for Someone with Alzheimer's to Undergo Cataract Surgery?
July 2014 The notion that cataract surgery for someone with Alzheimer's or other type of dementia is unnecessary, too risky or too stressful for the patient is going by the wayside. New evidence shows that improved vision after cataract surgery enhances both cognition and quality of life.
According to a clinical study presented at the Alzheimer's Association International Conference 2014 this month, both dementia patients and their caregivers benefit when the patient can see better.
By and large, the patients are more mobile, can function better and demonstrate slower memory decline than those who don't have needed cataract surgery.
The stance of the Alzheimer's Association is that people with dementia have the right to any medical treatment available, including cataract surgery.
Cataract Surgery Lowers Risk of Falls
May 2014 The risk of falling increases with age for just about everyone. But with the poor vision that a cataract brings, that risk increases dramatically.
A study of more than 400 Vietnamese people aged 50 or more with cataracts in both eyes looked at how many falls each person had before and after undergoing cataract surgery.
In the year after surgery on one eye, the risk of a fall decreased by 78 percent.
The results suggest that waiting for a cataract to worsen before having it removed increases the possibility of a fall, so it may be wiser not to wait.
The study was presented this month at the annual meeting of the Association for Research in Vision and Ophthalmology.
Stopping Smoking May Lower Risk of Cataracts
January 2014 Researchers in Sweden have released findings from a study of smokers that shows decreased levels of smoking may lower cataract risk.
Researchers followed nearly 45,000 Swedish men and found a gradual drop in cataract risk among former smokers: 20 years after quitting, their risk had fallen by about half.
The researchers found that smokers of more than 15 cigarettes a day had a 42 percent increased risk of cataract extraction compared with men who had never smoked. They also found that men who had smoked an average of more than 15 cigarettes a day but had stopped smoking more than 20 years earlier had a 21 percent increased risk.
For men who had been lighter smokers, the increased risk of cataract fell more quickly after quitting, but never reached the level of those who had never smoked.
The researchers also published a study in 2005 detailing the relationship between smoking cessation and cataract risk in women. Women who smoked six to 10 cigarettes a day but had ceased smoking 10 years earlier, and women who smoked more than 10 cigarettes a day but had ceased smoking 20 years earlier, were found to have a relative risk of cataracts not significantly different from women who had never smoked.
But for women who smoked more, it took 20 years before cataract risk was no longer greater than for women who had never smoked, the study concluded.
Cataract Surgery Patients Live Longer
November 2013 New research from Australia has confirmed that there is a 40 percent lower long-term mortality risk in people who have had cataract surgery.
Correction of cataract-related vision loss may increase optimism and emotional well-being, and this may result in a longer life span.
The research used data gathered in the Blue Mountains Eye Study, which examined vision and common eye diseases in an older Australian population.
The study compared people over age 49 who had cataract-related vision loss and underwent cataract surgery to correct this with those similarly aged who had the same type of vision loss but did not have the surgery.
Adjustments were made for age and gender, as well as a number of mortality risk factors, such as high blood pressure, diabetes, smoking, heart disease and body mass index.
Previous studies have shown that older persons with cataract-related visual impairment likely have a greater mortality risk than their peers who have normal vision and that cataract surgery might reduce that risk.
While the association between correction of cataract-related vision problems and reduced mortality risk is not clearly understood, possible factors may include improvements in physical and emotional well-being, optimism and greater confidence associated with independent living after vision improvement.
Aspheric IOLs Often Provide Better Contrast Sensitivity
Than Spherical IOLs, Study Finds
July 2013 Aspheric intraocular lenses (IOLs) implanted during cataract surgery often provide better contrast sensitivity than standard spherical IOLs, especially in dim light, according to an analysis of multiple clinical trials that was performed by researchers in Germany.
During cataract surgery, the clouded natural lens of the eye is replaced with an artificial implantable lens. Traditional IOLs significantly improve vision, but do not correct spherical aberration, an optical imperfection that can reduce image quality and cause increased glare and halos.
Aspheric IOLs are designed to reduce spherical aberration and provide superior quality of vision. They accomplish this by changing in curvature slightly from the center of the lens to the periphery to more closely mimic the optics of the human crystalline lens.
In the study, the investigators searched international peer-reviewed literature for studies that compared visual outcomes after cataract surgery for both types of IOLs.
Post-surgical visual outcomes evaluated included best-corrected visual acuity (BCVA), contrast sensitivity and subjective perception of vision quality.
Forty-three studies were included in the analysis, comprising 2,076 eyes implanted with aspheric IOLs and 2,034 eyes implanted with spherical IOLs.
Pooled results of the studies revealed aspheric IOLs provided better contrast sensitivity than spherical IOLs, especially under dim light. But there was no clinically significant difference in BCVA between aspheric and spherical IOLs, and questionnaires of patients' subjective perception of their vision quality after cataract surgery revealed no significant advantage for either type of IOL.
The study was published online by the journal Ophthalmology in June.
Man Punched in the Eye Develops Star-Shaped Cataract
April 2013 A punch in the eye can make you see stars literally. An Austrian man has developed a star-shaped (stellate) cataract after a blow to the eye that had occurred nearly nine months earlier, according to a case report in the New England Journal of Medicine.
Image: © New England Journal of Medicine
The 55-year-old experienced increasingly blurry vision over the six months after the punch, after which time he visited his eye doctor. The trauma to the eye had damaged the eye's lens, triggering the formation of a cataract and a peculiarly shaped one at that.
Cataracts typically form with old age, but it's also common for them to develop after an eye injury. What is most striking about this particular case is that the cataract formed a distinct star shape.
To help prevent unnecessary trauma to the eye, always wear protective eyewear during sports and safety glasses or goggles when working with heavy machinery or chemicals. (And stay out of fist fights!)
Lower Risk of Hip Fracture After Cataract Surgery
August 2012 Here's another reason not to delay surgery if you're older and receive a cataract diagnosis.
A study of about 1.1 million 65-and-older Medicare beneficiaries with cataracts during 2002-2009 revealed that those who underwent cataract removal had less risk of hip fracture one year later compared with those who did not have the cataract surgery during that time.
Watch this video for more details about cataract surgery resulting in a lower risk of hip fracture among older patients.
Hip and other fractures can be very dangerous in older people, causing illness and even death, and poor vision is one of the reasons for loss of balance that results in falls and hip fracture.
During the one-year study period for each person, the overall fracture incidence was 1.3 percent.
But those who underwent cataract surgery had a 16 percent decrease in the adjusted odds of hip fracture compared with those who did not have the surgery. In those with severe cataract, the adjusted odds of hip fracture was 23 percent less.
A report of the study is appearing this month in JAMA (Journal of the American Medical Association).
Time To Think About Cataracts
June 2012 June is Cataract Awareness Month, so if you're age 40 or older, make sure you're getting regular eye exams to detect any changes to your eyes and vision.
Cataracts can really sneak up on you, and you may not realize that your vision is becoming cloudy until an eye exam reveals it.
Prevent Blindness America says that more than 22 million Americans age 40 and older have cataracts. The organization has a toll-free number you can call with questions about cataracts and cataract surgery: (800) 331-2020.
If you're worried about having cataract surgery, keep in mind that it's the most commonly performed surgical procedure in the United States, with relatively few complications. For more information, please read our cataract surgery article.
How Old Is too Old to Have Cataract Surgery?
May 2012 If you look at the example of 109-year-old Guo Liansheng, there may not be an upper age limit for cataract surgery. After all, everybody wants to see well at all ages, right?
Madam Guo may have set a Guinness World Record for the World's Oldest Cataract Surgery Patient (the decision is pending).
Last year, Dr. Chu Tao of Shanghai New Vision Ophthalmic Hospital removed the cataract in her left eye and replaced it with an intraocular lens manufactured by UK company Rayner Intraocular Lenses Ltd.
Before the surgery, Madam Guo could barely see even changes in light. Afterward, she was able to see her infant great-great-granddaughter's face clearly for the first time.
And now, a year later, Dr. Chu Tao has performed the surgery in her other eye, in time for her to see her relatives who visited for the Year of the Dragon New Year celebrations.
Please click here for more cataract news from 2011.
[Page updated March 27, 2015]