All About Cataracts

A popular medicine taken by men for benign prostatic hyperplasia, commonly known as BPH or an enlarged prostate gland, is associated with increased risk for serious complications after cataract surgery, according to a study published in the May 20, 2009 issue of the Journal of the American Medical Association (JAMA). 

Flomax (tamsulosin HCl, Boehringer Ingelheim Pharmaceuticals) is a popular prescription medication to treat male urinary symptoms due to BPH. Symptoms include the need to urinate often, waking up several times during the night to go, a weak urinary stream and frequently feeling an urgent need to urinate.

BPH is common among older men: It is estimated that more than 50 percent of men over age 60 and almost all men over age 80 have symptoms of an enlarged prostate. The condition can also affect men in their 40s and 50s.

Tamsulosin HCl, the active ingredient in Flomax, belongs to a category of drugs called alpha blockers. Alpha blockers relax certain muscles and help small blood vessels remain open. In addition to treating BPH, alpha blockers are used to treat high blood pressure.

Researchers in Canada recently conducted a retrospective study of over 96,000 men age 66 years or older who had cataract surgery between 2002 and 2007. Of these patients, 3,550 (3.7 percent) had taken tamsulosin within two weeks of their cataract procedure and 7,426 (7.7 percent) others had taken other alpha blockers within two weeks of surgery.

Adverse events following cataract surgery were significantly more common among patients with recent tamsulosin exposure (7.5 percent) than among controls (2.7 percent) matched for age, surgeon and date of cataract surgery. There was no significant increase in the risk of adverse events following cataract surgery from recent use of other alpha blockers for treatment of BPH or high blood pressure.

Serious cataract surgery complications associated with recent Flomax use include retinal detachment, dislocation of the intraocular lens and endophthalmitis (inflammation of the interior of the eye, usually caused by infection).

Take Home Message: If you are currently taking Flomax for BPH symptoms, be sure to discuss this with your cataract surgeon prior to surgery. He or she may recommend you temporarily discontinue BPH treatment or switch to a different alpha blocker for a period of time before and after your cataract procedure to reduce your risk of medication-related surgical complications.

Source:  Association between tamsulosin and serious ophthalmic adverse events in older men following cataract surgery. JAMA. May 20, 2009.

Cataracts are the leading cause of blindness globally, and three programs in the developing world seek to help people blinded by cataracts to regain their sight.

At the recent annual meeting of the American Society of Cataract and Refractive Surgery (ASCRS), eye surgeon David F. Chang, MD, described how the Aravind Eye Hospital system in southern India, the Tilganga Eye Center in Kathmandu, Nepal and Project Vision in China are seeking to restore the vision of poor and aging populations in remote and under-served areas of the world.

Acccording to Dr. Chang, a clinical professor of ophthalmology at the University of California, San Francisco, based on the World Health Organization (WHO) definition of blindness as best-corrected visual acuity (BCVA) of 20/400 or worse, more than 18 million people worldwide are blind in both eyes due to cataracts.

That number grows to 54 million when considering how many people have BCVA worse than 20/200 (frequently called “legal blindness”) and balloons to 144 million if you include people with BCVA of 20/60 or worse due to cataracts. This final category describes people with low vision, who typically cannot see well enough to obtain an unrestricted driver’s license in the United States.  

 But while cataracts affect virtually all aging populations, there are many obstacles to the surgical treatment of cataracts in developing countries. These obstacles include the expense of surgical equipment and intraocular lenses (IOLs), a shortage of ophthalmologists in these regions and a lack of training programs for cataract surgeons and surgical staff in the developing world.

Dr. Chang described three programs that are providing safe, fast and low-cost cataract surgery for the poor in under-served regions of the world:

• The Aravind Eye Hospital System in southern India has been providing charitable eye care and cataract surgery on a large scale for more than 30 years. It was founded by Govindappa Venkataswamy, MD. Patients in remote villages are screened for cataracts on a Sunday, are transported by bus to a regional Aravind eye center that same evening and have cataract surgery the following day. On a typical Monday, 300 to 400 cataract surgeries are performed. “To maximize efficiency, every step of the preparation and procedure is standardized, and doctors and staff perform their roles with military precision,” said Dr. Chang. The Aravind hospital system controls costs by manufacturing its own supplies, including IOLs. Outcome studies have demonstrated that this high-volume surgical approach is safe and effective, and of the approximately 200,000 cataract surgeries performed each year at Aravind’s five regional hospitals, 70 percent are performed at no cost to the patient.

• The Tilganga Eye Centre in Kathmandu, Nepal was founded by Sanduk Ruit, MD. Along with Geoffrey Tabin, MD, Dr. Ruit also founded the Himalayan Cataract Project (HCP) in 1995. The goal of the program is to eradicate cataract blindness in Nepal by establishing outreach eye clinics in rural villages outside Kathmandu. The HCP uses portable generators and surgical equipment and transforms places such as open-air classrooms into temporary operating rooms. IOLs for the procedures are manufactured at Tilganga Eye Centre, which also sells the IOLs to 60 countries in the developing world. The center is also opening a new wing to train cataract surgeons from other countries.

• Project Vision in China was founded by Dennis Lam, MD, chairman of ophthalmology at Chinese University of Hong Kong. The project is a collaboration between the university, private philanthropy in Hong Kong, a training center in China and the Chinese government, according to Dr. Chang. Seventy percent of China’s population, or 900 million people, live in rural villages with limited access to medical care. In addition, most of the Chinese population cannot afford cataract surgery. Project Vision provides surgical equipment and training to nine county-level hospitals throughout rural China. In exchange, the hospitals agree to lower their charges for cataract surgery to $90 (USD) per case.

Concluding his ASCRS presentation, Dr. Chang noted that these three model programs prove that “there is hope” of overcoming the formidable challenge of cataract blindness in the developing world.

Source: Three programs offer hope. Ophthalmology Times. May 1, 2009

The U.S. Food and Drug Administration (FDA) recently approved a new astigmatism-correcting intraocular lens (IOL) for use in cataract surgery. The new lens, called the AcrySof IQ Toric IOL, is manufactured by Alcon and is now available for use by cataract surgeons in the United States.

In addition to having a toric design to correct astigmatism, the new premium IOL also has aspheric curves to reduce a common post-surgical optical error called spherical aberration. By reducing spherical aberration, the AcrySof IQ Toric IOL is designed to improve image quality and contrast sensitivity for better night driving vision and sharper vision overall.

In a clinical trial required by the FDA prior to approval, among 37 patients who had the IOL implanted bilaterally for the treatment of cataracts and astigmatism, 98 percent did not need prescription eyeglasses for distance vision six months after surgery. Also, the lens continued to show good rotational stability when checked one year after surgery. 

According to Alcon, the AcrySof IQ Toric IOL is a good choice for any patient undergoing cataract surgery who has 0.75 diopter (D) or more corneal astigmatism prior to surgery. The IOL corrects up to 2.50 D of astigmatism, and it can be combined with a procedure called limbal relaxing incisions to correct even higher amounts of astigmatism.

Like other premium IOLs, the AcrySof IQ Toric IOL costs more than a conventional monofocal intraocular lens and will increase your cataract surgery cost. For details, consult a cataract surgeon near you.

Cataracts are a common cause of vision loss in older adults.

In 2004, the Eye Diseases Prevalence Research Group (EDPRG), estimated that 20.5 million Americans (17.2 percent) over age 40 had a cataract in either eye, and 6.1 million (5.1 percent) already had a cataract removed. And according to the National Eye Institute (NEI), by age 80, more than half of all Americans either have a cataract or have had cataract surgery.

But, besides advancing age, are there other risk factors associated with the development of cataracts?

A large study of 3,721 adults in Australia found the following additional risk factors for cataracts:

•  Women are more likely than men to develop cortical cataracts. (This was also true in the American study by EDPRG, which found that women are almost 40 percent more likely than men to develop cataracts.)
• Working as a laborer (compared to having a white-collar occupation) and myopia also are risk factors associated with cortical cataracts.
• Cigarette smoking and a history or arthritis are associated with the development of nuclear cataracts.
• Diabetes and taking calcium channel blockers (medications commonly used to treat high blood pressure) for more than five years are risk factors associated with posterior subcapsular cataracts.

It is likely that in the United States, there will be an increase in diabetes-related cataracts in the future. According to the Centers for Disease Control and Prevention, 34 percent of Americans over age 20 are obese, and obesity is a primary risk factor for Type 2 diabetes. Currently, 24 million Americans (8 percent) have known diabetes, and an estimated 57 million (19 percent) have “pre-diabetes,” meaning they have blood glucose levels that are higher than normal but not yet high enough to be diagnosed as diabetes.

Some researchers believe that by the year 2050, the number of diabetes-related cataracts will increase by over 200 percent. Also, the number of Americans with diabetic retinopathy (another vision-threatening complication of diabetes) is expected to increase from 1.2 million to 3.4 million over the same period. 

The take-home message: If you want to lower your risk for cataracts, two steps you can take are to avoid or quit smoking and, if you are overweight or have pre-diabetes, to consult with your doctor and begin a diet and exercise program to lower your risk of diabetes.

Sources:

1. Prevalence of cataract and pseudophakia/aphakia among adults in the United States. Archives of Ophthalmology. April 2004.
2. Development of cataract and associated risk factors: The Visual Impairment Project. Archives of Ophthalmology. January 2006.
3. Diabetes and obesity: A challenge for every ophthalmologist. Archives of Ophthalmology. March 2009.