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March 2008

 
Journal Highlights
New Findings from Ophthalmology, AJO and Archives
 
 

March’s Ophthalmology:

March’s American Journal of Ophthalmology:

January’s Archives of Ophthalmology:

Roundup of Other Journals:


Ophthalmology

Seatbelts, Air Bags, Car Accidents and Ocular Injury
March’s Ophthalmology

While previous studies have demonstrated that air bags reduce motor vehicle accident fatalities by nearly 32 percent, air bags also have been associated with ocular injuries at an estimated incidence of 5 percent. Rao et al. wanted to know the impact of seat belt use on ocular injuries when air bags deploy. They reviewed charts of 47 patients involved in motor vehicle accidents with air bag deployment.

Results showed that 71 percent of patients who did not wear seat belts experienced type III ocular injuries, compared with 31 percent who wore seat belts. Posterior segment injuries only occurred in patients who did not wear seat belts. At three-month follow-up, 76 percent of patients who did not wear seat belts had a visual acuity of 20/40 or better, in contrast with 96 percent of those who wore seat belts.


When Primary Acquired Melanosis Transforms to Melanoma
March’s Ophthalmology

To gain insight into the clinical features of primary acquired melanosis (PAM) that are predictive of progression to melanoma, Shields et al. conducted a chart review of 311 eyes with conjunctival PAM without melanoma at initial examination.

The mean patient age at diagnosis was 56 years. Sixty-two percent of patients were female, and 96 percent of patients were Caucasian. Most patients were asymptomatic or noticed only a patch of pigment. The extent of PAM was 3 clock hours or less in 76 percent of patients and more than 3 clock hours in 23 percent. In terms of progression to melanoma, small foci of PAM, less than 1 clock hour, generally remained stable, but larger lesions were more likely to evolve into invasive melanoma. PAM without cellular atypia and PAM with mild atypia carried almost no risk of progression, while PAM with severe atypia showed 13 percent transformation to melanoma.


Pressure Generation in Bitemporal Hemianopia
March’s Ophthalmology

In an effort to examine a proposed mechanical theory for bitemporal hemianopia that involves intraneural pressures, Kosmorsky et al. measured the pressure in the temporal and central aspects of the optic chiasm simultaneously during compression.

The chiasm was exposed to an external deformation force created by a Foley catheter in the pituitary fossa. This balloon mimicked the effect of a tumor. Higher pressures were always generated in the central aspect of the chiasm as compared with the temporal aspect of the chiasm.

The authors hypothesize that the unusual geometry of the optic chiasm makes the crossing nasal fibers more prone to a deformation stress exerted from below. This nonuniform pressure results in a greater effective stress on the crossing fibers of the chiasm and may be responsible for bitemporal hemianopia.


New Eye Lesions in Treated Congenital Toxoplasmosis
March’s Ophthalmology

Phan et al. describe the natural history of chorioretinal lesions in a group of 132 children with congenital toxoplasmosis who were treated with pyrimethamine, sulfadiazine and leucovorin in their first year of life.

Contrary to previous reports in the literature, this study showed that new, centrally located chorioretinal lesions are uncommon in these children, regardless of whether they experienced severe systemic disease at birth. Specifically, by 10.8 years of age, 15 of 108 children (14 percent) had developed new central lesions, and 27 (25 percent) had newly detected lesions peripherally. Ten (9 percent) had more than one occurrence of new lesions developing, and 13 (12 percent) had new lesions in both eyes. Of those who developed new lesions, 14 children (41 percent) developed them at age 10 or later.


Hydroxyapatite Implants: A 15-Year Retrospective
March’s Ophthalmology

Yoon et al. report one surgeon’s experience with implanting 802 hydroxyapatite orbital implants from May 1990 to December 2005. Throughout the years, the surgeon used a variety of wrapping materials, including Tutoplast Dura, vicryl mesh, autogenous sclera and polyesterurethane.

Implant exposure occurred in 17 patients (2.1 percent) before pegging and in 14 patients (4 percent) after pegging. This exposure rate was significantly higher in eyes eviscerated with keratectomy (7.2 percent) than without (1.1 percent). The exposure rate was higher from 1990 to 1994 than later periods, a finding attributed to an improvement in the surgeon’s technique of hydroxyapatite implantation over time. They noted that toward the end of the study period, implant size was larger, more time was spent on proper placement of the implant within the posterior socket, and the surgeon closed the posterior and anterior Tenon’s capsule and conjunctiva separately with layer-by-layer interrupted sutures.


American Journal of Ophthalmology

Outcome of MRSA-Associated Acute Endophthalmitis
March’s AJO

Deramo et al. determined the frequency, visual outcome and bacterial sensitivity in cases of methicillin resistant Staphylococcus aureus (MRSA)–associated acute endophthalmitis occurring after cataract surgery.

The authors identified 64 cases of acute endophthalmitis occurring within six weeks after cataract surgery over a three-year interval. Thirty-three of the 64 eyes were culture-positive, and six of the 33 cases (18.2 percent) demonstrated MRSA infection. All six eyes were started on fluoroquinolone antibiotics two or three days before cataract surgery. Corneal abnormalities were noted in five of the six cases, ranging from wound infection to diffuse corneal opacification. Visual acuity at last follow-up was no light perception (NLP) in two eyes, hand movements in two eyes and 20/30 or better in two eyes. One eye with NLP underwent enucleation within three days of presentation. All six organisms were sensitive in vitro to both gentamicin and vancomycin, but no organism was sensitive to any fluoroquinolone antibiotic (although not all organisms were tested against all fluoroquinolones).


Vision Function in HIV-Infected Individuals
March’s AJO

The Studies of Ocular Complications of AIDS research group evaluated the prevalence and risk factors for vision loss in patients with clinical or immunologic AIDS but without infectious retinitis.

The 1,351 patients (2,671 eyes) in this study had been diagnosed with AIDS but did not have major ocular complications of AIDS. The patients received standardized measurements of visual acuity, automated perimetry and contrast sensitivity, and the authors analyzed and correlated these measurements with the patients’ health and medical data relating to HIV infection. In this report, they evaluated the correlations between vision function testing and HIV-related risk factors and medical testing.

They found significant (P < 0.05) associations between measures of decreasing vision function and indices of increasing disease severity, including Karnofsky score and hemoglobin. A significant relationship was seen between low-contrast sensitivity and decreasing levels of CD4+ T-cell count. Three percent of eyes had a visual acuity worse than 20/40 Snellen equivalents, which was significantly associated with a history of opportunistic infections and low Karnofsky score. When compared with external groups with normal vision, 39 percent of eyes had abnormal mean deviation on automated perimetry, 33 percent had abnormal pattern standard deviation and 12 percent of eyes had low-contrast sensitivity.


Human Leucocyte Antigen-B27–Associated Uveitis: Follow-Up and Gender Differences
March’s AJO

Braakenburg et al. evaluated the clinical features and gender differences in human leucocyte antigen-B27 (HLA-B27)–associated acute anterior uveitis in a long-term, retrospective cohort. The clinical records of 177 HLA-B27–positive patients (96 males and 81 females) with acute anterior uveitis were evaluated. The clinical data were analyzed at standardized intervals (one, five and 10 years after the onset of uveitis).

Average age at onset was 36 years, with no differences between males and females. HLA-B27–associated systemic disease developed earlier in males than in females (31 vs. 37 years). Over time, however, males and females were at equal risk of developing an HLA-B27–associated systemic disease. Bilateral uveitis developed more frequently in females. At 10-year follow-up, there were no bilateral cases of visual acuity of less than 0.5.


Archives of Ophthalmology

Lutein, Zeaxanthin, Vitamin E and Risk of Cataract in Women
January’s Archives

Christen et al. examined the relation between dietary intake of carotenoids and vitamins C and E, and risk of cataract in prospective data from the Women’s Health Study.

The study included 35,551 women who completed a food-frequency questionnaire at baseline and were free of a diagnosis of cataract. During an average of 10 years of follow-up, 2,031 cases of incident cataract were confirmed with medical record data. Comparing women in the highest fifth of intake with those in the lowest fifth, the researchers observed significantly reduced risk of cataract for high intake of lutein, zeaxanthin and vitamin E from food and supplements. No significant associations with cataract were observed for high intake of vitamin C or the carotenoids, alpha-carotene, beta-carotene, beta-cryptoxanthin or lycopene.


Optic Neuritis and Relapsing Neuromyelitis Optica
January’s Archives

Papais-Alvarenga et al. conducted a study to describe the spectrum and natural history of optic neuritis in relapsing neuromyelitis optica.

Unilateral optic neuritis was the initial feature in 53.3 percent of the 60 patients involved in the study. Recurrent optic neuritis before myelitis occurred in 18.3 percent of the patients. Visual impairment was severe at the nadir of the visual index event in 78.3 percent of the patients, with a high remission rate. In the median disease duration of eight years, 118 acute isolated visual events occurred. At the last follow-up, 53.3 percent of patients had bilateral visual impairment, and 63.3 percent were blind in at least one eye.

The authors conclude that optic neuritis in patients with relapsing neuromyelitis optica has a severe and acute onset, with predominantly unilateral lesions followed by improvement of clinical symptoms. In the long-term, the disease leads to severe bilateral visual impairment.


Retained Subfoveal Perfluorocarbon Liquid After Vitreoretinal Surgery
January’s Archives

Le Tien et al. reported a surgical procedure to displace subfoveal perfluorocarbon liquid (PFCL) that was retained after otherwise successful vitrectomy repair of complex retinal detachment.

In a retrospective case series, three patients with low vision due to retained subfoveal PFCL bleb were managed with the same procedure. Therapeutic retinal detachments at the posterior pole and the inferior periphery were created by injecting balanced salt solution through a 39-gauge retinotomy near the inferotemporal vessels. Fluid-air exchange was then performed, followed by short-term postoperative up-right head positioning. In all cases, the therapeutic retinal detachment was transient, and the PFCL droplets were successfully and promptly displaced toward the subretinal inferior periphery. After six months, anatomical and functional outcomes were satisfactory.

The authors conclude that this procedure allows anatomical macular recovery and improvement of visual acuity. They add that it should be considered as an alternative to direct aspiration of PFCL through a juxtafoveal retinotomy, which risks damage to the foveal region.
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Ophthalmology summaries are written by Lori Baker Schena and edited by John Kerrison, MD. American Journal of Ophthalmology summaries are edited by Thomas J. Liesegang, MD. Archives of Ophthalmology summaries are written by the lead authors.


Roundup of Other Journals

Surgeons May Be at Risk for Musculoskeletal Injuries
Dermatologic Surgery
2007;33:1304–1314

Esser et al. used Mohs’ surgery as a model to examine the risk of musculoskeletal injuries in office-based surgery. This survey-guided, observation-based study involved 17 surgeons who perform Mohs’ surgery.

Sixteen of the 17 surgeons reported musculoskeletal symptoms caused by or made worse by performing surgery, with symptoms beginning at a mean age of 35.4 years.

Neck-related pain and stiffness represented the most common complaint, followed by shoulder and lower back pain, eye fatigue and headaches, and leg edema. Videotapes of these surgeons, reviewed by an ergonomist, showed problems with operating room setup, posture, exertion, positioning, lighting and length of procedures.

The researchers conclude that improving the ergonomics of the office-based surgical setting could possibly help surgeons avoid musculoskeletal injuries.


Müller’s Muscle-Conjunctival Resection to Correct Ptosis
Archives of Facial Plastic Surgery
2007;9:413–417

Müller’s muscle-conjunctival resection (MMCR) is a procedure traditionally used to correct mild to moderate upper eyelid ptosis. Simon et al. reviewed the medical records of 80 patients with good levator muscle function who underwent 131 MMCR procedures for correction of upper eyelid ptosis. They found that this surgical approach resulted in improved eyelid position, with eyelid symmetry within 1 mm achieved in 81 percent of the patients.

In addition, while phenylephrine eyedrops are routinely used to predict the final eyelid position that may be achieved with MMCR, phenylephrine testing in this study underestimated the extent of ptosis achieved with MMCR. The researchers also found that trend-line calculations for the extent of MMCR and ptosis correction did not correlate with clinical outcome, highlighting the complex relationship of MMCR and surgical results.

These findings notwithstanding, MMCR appears to be an excellent and predictable surgical approach to correct eyelid ptosis with good levator muscle function.


Imaging Retina Cells in the Human Eye
Eye
2007;21:518–520

The ability to visualize and count retinal cells would be advantageous in the early diagnosis and monitoring of diseases such as age-related macular degeneration, glaucoma and retinal degeneration. While cellular imaging is being performed in the eyes of laboratory animals, it has yet to be successfully done in human eyes. However, according to Paques et al., researchers are working diligently to bring cellular-imaging technology to human eyes.

In this paper, the authors describe progress in the field, including the advent of different technologies such as the scanning-laser ophthalmoscope, optical coherence tomography (in spectral domain a-mode or en-face mode), adaptive optics and second harmonic generation imaging. These devices have successfully performed cellular-level imaging of photoreceptors, the nerve fiber layer and capillaries.

The investigators describe their work using fundus imaging techniques with adaptive optics to visualize the perifoveal cone photoreceptor array. They note that the transition of this technology to the clinical setting will require successfully addressing biological, medical and technical challenges.


Interferon Beta-1a and Doxycycline for Multiple Sclerosis
Archives of Neurology
Published online December 10, 2007

Results from a 15-patient, open-label study have found that the treatment combination of oral doxycycline and interferon beta-1a may be safe, effective and well-tolerated in patients with relapsing-remitting multiple sclerosis.

Minagar et al. administered intramuscular interferon beta-1a and oral doxycycline (100 mg daily) for four months to participants who underwent a monthly neurologic examination, magnetic resonance imaging of the brain with triple-dose gadolinium and blood work.

Results indicated that with the exception of one patient who developed a relapse (optic neuritis), all of the other patients became clinically stable, demonstrating improvement of their Expanded Disability Status Scale scores, a method of quantifying disability in multiple sclerosis. The patient with optic neuritis received intravenous methylprednisolone (1 g daily) for five days. In addition, participants experienced a significant decrease in the number of contrast-enhancing lesions on brain MRI, providing evidence that this therapeutic approach reduced the inflammatory cascade of multiple sclerosis and stabilized the blood-brain barrier.
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Roundup of Other Journals is written by Lori Baker Schena and edited by Deepak P. Edward, MD.