Ophthalmology Dec.'08 research highlights

SAN FRANCISCO, CA---This month's Ophthalmology, the journal of the American Academy of Ophthalmology, reports on eye disorders that may occur in people taking statins, on a new system that predicts soldiers' visual recovery after combat eye trauma, and on use of glaucoma patients' opinions to improve testing and treatment.

Statin medications are used to lower patients' cholesterol levels, thus helping prevent coronary heart disease, stroke and other deaths related to high cholesterol levels. Statin use has grown rapidly since 1992, and seems likely to increase in light of the recent, widely-reported Jupiter Study on statin benefits in patients with low cholesterol but elevated C-reactive protein. Eye disorders related to statins are rare, occurring in about 0.1 percent of patients (0.5 to 2.5 percent when gemfibrozil, another type of cholesterol-lowering drug, is taken simultaneously). The study led by F.W. Fraunfelder, MD, of the Casey Eye Institute, Oregon Health & Science University, is the first to systematically report on the association of eye disorders with statin use.

Dr. Fraunfelder's group analyzed statin-associated reports of double vision (diplopia), drooping of the upper eyelid (ptosis), and loss of full range of motion of the eyes (ophthalmoplegia) in the databases of the National Registry of Drug-Induced Ocular Side Effects, the World Health Organization, and the Food and Drug Administration. Since statins were known to cause skeletal muscle disorders in some patients, a similar affect was plausible in the eye muscles. The average patient age was 64.5 years, and the case reports included 143 males, 91 females, and 22 persons with gender unspecified. The average statin dose of patients who exhibited one or more eye disorder was within ranges recommended by drug manufacturers, and the average time from beginning of therapy to developing an adverse drug reaction (ADR) was 8.3 months. There were 23 cases of loss of eye range of motion, 8 cases of ptosis, and 18 cases of ptosis in conjunction with double vision; disorders in all patients apparently resolved completely when statins were discontinued. From the ADR reports, the researchers could not determine precisely which eye muscles were involved, or time needed to full recovery after statin discontinuation, for individual cases.

"We advise physicians prescribing statins to be aware that these eye disorders may result, and that medications should be discontinued if so. When a patient has one of these eye disorders, he should be rigorously evaluated to determine the cause, and statin use should be taken into account," Dr. Fraunfelder concludes.

When soldiers sustain eye injuries on the battlefields of Iraq or Afghanistan, one of the first questions families ask military doctors is whether their loved ones will recover good vision. But until Eric D. Weichel, MD, and his colleagues at Walter Reed Army Medical Center (WRAMC) tackled the issue, there was no standard for predicting visual recovery. Dr. Weichel's team studied patient records for 523 consecutive eye injuries sustained by 387 US soldiers treated at WRAMC between March 2003 and October 2006. The researchers wanted to know whether a system called the ocular trauma score (OTS), developed for use with non-combat eye trauma by Ferenc Kuhn, MD, was applicable to soldiers' eye injuries. The OTS enables the care provider to calculate the probability that a particular eye trauma patient will obtain a visual range by six months after the injury. This study concluded that the OTS is a valid system for predicting visual acuity outcomes following combat ocular trauma (COT). "We can now answer many questions about visual prognosis for service members and their families," said Dr. Weichel. "The assessment, treatment, and counseling protocols we developed based on this and related COT studies have been integrated into all phases of eye injury care, from military surgical intensive care units through follow-up and rehabilitation in Veterans' Administration centers."

Dr. Weichel's team collected 201 eye injury-related variables for each soldier studied, as well as measurements of the soldier's best-corrected visual acuity (BCVA) taken as soon as possible after the injury and at six months post-injury. Initial BCVA measurements were not available for all subjects since severely injured soldiers (unconscious or intubated) were unable to communicate with doctors about their visual status. The data was then categorized using the OTS. A higher OTS score indicated a higher likelihood that good visual acuity would be recovered. The visual recovery prognosis was worst for soldiers who sustained injuries to the globe of the eye combined with lacerations to the eyelids or fractures to the bones around the eye, and/or with injuries to the cranial nerves, visual nerves or brain structures. Thirty-three percent of the soldiers had worse than 20/200 vision in one eye, and globe injuries occurred in both of the patient's eyes in 36 percent of the 523 eyes studied. Many soldiers sustained other devastating injuries such as traumatic brain injury (66%) and severe arm/ leg injuries (44%).

The first quantitative study of how glaucoma patients perceive glaucoma assessment tests and how these perceptions may impact test results and follow-up care was completed by Stuart K Gardiner, PhD, and his colleagues at the Discoveries in Sight Laboratory, Devers Eye Institute of the Legacy Health System, Portland OR. Patients who have or are at risk for glaucoma, a disorder of the optic nerve that can lead to severe vision loss, are evaluated by their Eye MDs (ophthalmologists) in a series of tests, often at yearly follow-up visits. Though the quality of assessment data gleaned from each test is the key use criteria, patients' experiences are also important, since dislike of or discomfort with testing may affect whether patients are willing to keep future appointments and follow treatment plans. Most glaucoma visual field tests require patients to concentrate and respond accurately; if a patient is unmotivated, test result validity could be reduced.

The 101 patients in the study had either high risk ocular hypertension (OH), a precursor of glaucoma, or early glaucoma. Most had been followed in the clinic for about 10 years. The patients rated each of seven commonly used glaucoma tests from 0 (absolute dislike) to 10 (perfect satisfaction). The researchers then ranked the resulting scores for each subject from 1 (favorite test) to 7 (least favorite). Patients were also asked to describe why they liked or disliked the tests. Their remarks were considered anecdotal evidence, but when responses were similar for many subjects the evidence was accepted as a useful conclusion. The intraocular pressure (IOP) test was most favorably ranked, and many patients also liked the Heidelberg retinal tomography (HRT) test, in part because they could view images of the heads of their optic nerves during the exam. The short wavelength automated perimetry (SWAP) test was the "least favorite" of 48 patients; most said they disliked having to concentrate and respond for a sustained time period. Optic nerve photography was also disliked because of discomfort caused by dilation drops and exposure to bright light, and the inconvenience of lingering blurry vision.

Dr. Gardiner said, "Our study shows the importance of carefully explaining to patients the purpose of each test and of obtaining valid results. We also learned that modifying testing patterns, for example offering rest breaks or changing the test order, may improve the patient's experience and results. The findings will be useful in developing improved test formats and allowing clinicians to choose tests that patients tolerate well from the available alternatives."

Eds: Full texts of the studies are available from the Academy's media relations department.

AAO is the world's largest association of eye physicians and surgeons—Eye M.D.s—with more than 27,000 members worldwide. Eye health care is provided by the three "O's" – opticians, optometrists and ophthalmologists. It is the ophthalmologist, or Eye M.D., who can treat it all: eye diseases and injuries, and perform eye surgery. To find an Eye M.D. in your area, visit the Academy's Web site at www.aao.org