EyeNet Magazine


 
Journal Highlights
New Findings from Ophthalmology, AJO and Archives
 
 

June’s Ophthalmology:

June’s American Journal of Ophthalmology:

April’s Archives of Ophthalmology:

Roundup of Other Journals:

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Ophthalmology

IOL Comparison of Binocular Near Vision
June’s Ophthalmology

In a comparison of binocular near-vision performance in three IOLs (accommodating, multifocal and monofocal), Harman et al. found that the accommodating IOL and the multifocal IOL provided significantly better near-vision acuity at three months than the monofocal control group.

The prospective, double-masked trial involved 90 cataract surgery patients randomized to the three different lenses and followed at three and 18 months. The mean unaided and distance-corrected binocular near-vision acuities were similar in the accommodative and multifocal groups and were significantly better than in the control monofocal group. While the multifocal lens provided excellent near acuity, glare remained a problem.

The authors conclude that for patients who seek an increased chance of spectacle independence while avoiding photopic phenomena, the accommodative lens appears to be the most credible option of the three types of lens included in the study.


Genotype and AMD Treatment With Antioxidants and Zinc
June’s Ophthalmology

In a study investigating whether genotype can predict response in individuals considered at high risk for developing vision loss from advanced age-related macular degeneration, Klein et al. provide evidence that an individual’s response to antioxidant and zinc supplements June in fact be related to the complement factor H (CFH) genotype.

Using blood from 876 Caucasian participants of the Age-Related Eye Disease Study (AREDS), the investigators genotyped for the single nucleotide polymorphisms in the CFH and LOC387715/ ARMS2 genes.

They found that supplementation was associated with a greater reduction in AMD progression in those with the low-risk genotype (68 percent) compared with those with the high-risk genotype (11 percent). They assert that the results June imply that the strong genetic predisposition to AMD associated with the high-risk genotype might limit the benefits of zinc and antioxidants such as beta-carotene, vitamin C and vitamin E.

The authors conclude that the findings of the study must be corroborated before any suggestions can be made about modifying current treatment protocols for AMD.


Cardiovascular Disease and Choroidal Neovascularization
June’s Ophthalmology

Hogg et al. suggest that cardiovascular disease is associated with the development of choroidal neovascularization and June play an etiological role in the development of age-related macular degeneration.

This study involved 195 participants with CNV in at least one eye, 97 non-AMD participants and 115 control patients with no drusen or pigmentary irregularities in either eye. Using confounder-adjusted logistic regression, the investigators found that a history of cardiovascular disease was strongly associated with AMD. In addition, cigarette smoking, being in the highest quartile of body-mass index and being in a high quartile of serum cholesterol were positively associated with AMD. There was also a strong and significant trend of increasing odds of developing AMD with increasing severity of hypertension.


IOP Fluctuation, Ocular Hypertension and Glaucoma
June’s Ophthalmology

Medeiros et al. found that long-term fluctuations in IOP do not represent a significant risk factor for glaucoma development in untreated individuals with ocular hypertension.

In this observational cohort study, the researchers followed 252 eyes of 126 patients with untreated ocular hypertension. Forty eyes of 31 patients developed glaucoma during the follow-up period, with a mean IOP of 25.4 ± 4.2 mmHg during follow-up in the eyes that progressed to glaucoma and a mean of 24.1 ± 3.5 mmHg for the eyes that did not. Corresponding values for IOP fluctuation were 3.16 ± 1.35 mmHg and 2.77 ± 1.11 mmHg, respectively. In both the univariate and multivariate analyses, IOP fluctuation was not a risk factor for developing glaucoma, while mean IOP proved a significant risk for progression.

The authors note that these results agreed with those reported from the Early Manifest Glaucoma Trial that suggested IOP fluctuation is not significantly associated with the risk of glaucoma development or progression.


Tacrolimus for Ocular Surface Diseases
June’s Ophthalmology

Miyazaki et al. conducted a case series involving 10 patients to determine whether topical tacrolimus was efficacious in treating refractory ocular surface inflammatory disease. One patient had peripheral ulcerative keratitis with impending corneal perforation, one had a Mooren’s ulcer, two had scleroperikeratitis, five had atopic keratoconjunctivitis and one had vernal keratoconjunctivitis.

These patients were treated with topical tacrolimus ointment (0.02 percent). In all cases, patients experienced a marked to moderate improvement, including suppression of the melting reaction of the inflamed cornea, remission of scleroperikeratitis and reduction of both a giant papilla and corneal epithelial defect in severe atopic keratoconjunctivitis.

The authors conclude that tacrolimus ointment constitutes an effective alternative for ocular-surface inflammatory disorders, especially when treatment with systemic steroid or immune suppressant is contraindicated.


American Journal of Ophthalmology

Recurrence Patterns of Toxoplasmic Retinochoroiditis
June’s AJO

Holland et al. sought to determine whether there is a pattern to recurrences of toxoplasmic retinochoroiditis and to identify the risk factors for recurrence.

Data were collected for 143 patients with toxoplasmic retinochoroiditis, including gender, first-affected eye, age at first episode, mode of Toxoplasma gondii infection (congenital vs. postnatal), treatment history and presence of retinal scars at initial examination. The influence of host and disease factors on recurrence risk was analyzed using Cox regression with frailty modeling for correlated intrapatient recurrence times.

Follow-up of the 143 patients ranged from 0.3 to 41 years, and there were 323 episodes in first-affected eyes. Recurrence risk was highest immediately after an episode. Relative risk of recurrence declined 72 percent with each 10-year interval since first episode and declined 15 percent for each 10-year increase in age at first episode. Patients more than 40 years of age were at higher risk of recurrence than younger patients. Clusters of episodes occurred after prolonged disease-free intervals.


The Effect of DSEK on Corneal Optics
June’s AJO

Rao et al. evaluated the changes in corneal optical performance after Descemet’s stripping endothelial keratoplasty (DSEK).

The anterior segment in four eyes of four patients who underwent DSEK with cataract extraction and IOL implantation were imaged with anterior-segment optical coherence tomography. The curvature of the posterior surface of the donor graft was compared with that of the host cornea and the corneal thickness was measured. All eyes had a hyperopic refractive error after surgery. The posterior corneal curvature after surgery was greater than that before surgery. Average preoperative keratometry was 43.4 D, and after surgery it was 42.8 D using keratometry. However, when the postsurgical corneal power was calculated using the Gaussian optics method, the average value was 40.8 D.

The authors conclude that the addition of a donor corneal graft to the posterior surface of decompensated cornea June lessen the effective optical power of the cornea and June have implications for IOL power calculations in these eyes.


Fluidics Comparison of Phacoemulsification Machines
June’s AJO

Different phacoemulsification machines operate on varying physical principles. Georgegescu et al. compared three phacoemulsification machines for measurement accuracy and postocclusion surge (POS) in human cadaver eyes.

The tip vacuum and flow were compared with machine-indicated vacuum and flow. All machines were placed in two cadaver eyes and POS was determined. Vacuum (percent of actual) was 102 percent for the Alcon Infiniti, 93 percent for the Bausch & Lomb Stellaris and 108 percent for the Advanced Medical Optics Signature. When set at 60-ml/minute flow, actual flow and unoccluded flow vacuum were 56 ml/minute and 198 mmHg for the Infiniti, 54 ml/ minute and 180 mmHg for the Stellaris and 59 ml/minute and 115 mmHg for the Signature. POS in a 32-year-old eye was 0.33 mm for the Infiniti, 0.16 mm for the Stellaris and 0.13 mm for the Signature. POS in an 81-year-old eye was 1.51 mm for the Infiniti, 0.83 mm for the Stellaris and 0.67 mm for the Signature.


Antimicrobial Susceptibility in Ocular Isolates
June’s AJO

In the Ocular Tracking Resistance in United States Today study group, Asbell et al. annually evaluate in vitro antimicrobial susceptibility of Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae to ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin, penicillin, azithromycin, tobramycin, trimethoprim and polymyxin B in national samples of ocular isolates.

The group prospectively collected ocular isolates (197 S. aureus, 49 S. pneumoniae and 32 H. influenzae) from 35 institutions and also archived ocular isolates (760 S. pneumoniae and 356 H. influenzae) from 34 institutions. The isolates were tested by an independent laboratory. Mean minimum inhibitory concentrations that would inhibit growth of 90 percent of the tested isolates (MIC90) were interpreted as susceptible, intermediate or resistant, according to standardized breakpoints for systemic treatment. S. aureus isolates were classified as methicillin susceptible (MSSA) or methicillin resistant (MRSA).

MSSA and MRSA patterns were virtually identical for the fluoroquinolones. Trimethoprim was the only agent with high activity against MRSA. All S. pneumoniae isolates were susceptible to gatifloxacin, levofloxacin and moxifloxacin, while 90 percent were susceptible to ciprofloxacin. H. influenzae isolates were 100 percent susceptible to all agents except trimethoprim.


Archives of Ophthalmology

Menopausal and Reproductive Factors for AMD
April’s Archives

Feskanich et al. assessed various factors that contribute to lifetime estrogen exposure among roughly 75,000 postmenopausal women. After 22 years of follow-up, diagnoses of early (554) and neovascular (334) age-related macular degeneration were confirmed by medical record review. All AMD cases were severe enough to cause a visual acuity of 20/30 or worse.

Women currently using postmenopausal hormones (PMH) had a 48 percent lower risk of neovascular AMD compared with nonusers, and risk was 21 percent lower among women who had used oral contraceptives during their premenopausal years. When analyzed together, risk was lowest among the women who had used both PMH and oral contraceptives. In contrast to neovascular AMD, a 34 percent increased risk of early AMD was observed among current PMH users. This finding could not be explained by earlier or more frequent eye examinations among women who used PMH. Oral contraceptives use was not associated with early AMD.

Factors affecting endogenous estrogen, including ages at menarche and menopause, parity and number of reproductive years were generally unassociated with AMD.


Logistic Regression Analysis, Glaucoma Diagnosis and OCT
April’s Archives

Ferreras et al. calculated and validated a linear discriminant function measure using optical coherence tomography for discriminating between healthy eyes and eyes with early glaucomatous visual field loss.

A sample of 62 healthy individuals and 73 patients with open-angle glaucoma was used to determine a linear discriminant function based on the retinal nerve fiber layer thickness at each of the 12 clock-hour positions. Another independent sample of 280 normal eyes and 302 glaucomatous eyes was used to evaluate the diagnostic accuracy of the function. In the latter set, the proposed function and the best-provided OCT parameter (average thickness) yielded sensitivities of 74.5 percent and 67.8 percent, respectively, at a fixed specificity of 95 percent.


More Online

Read the latest published research at
the following Web sites:

American Journal
of Ophthalmology:

www.aao.org/one, then "Library"

Archives of Ophthalmology:
archopht.ama-assn.org

Ophthalmology:
www.aao.org/one, then "Library"


Roundup of Other Journals

Bestrophin-2 Gene Is Linked to IOP Generation
Investigative Ophthalmology & Visual Science
2008;49:1563–1570

Bakall et al. focused on the bestrophin-2 gene in mice and its possible role in IOP.

The researchers disrupted the bestrophin-2 gene by targeted insertion of the lacZ gene and then examined the bestrophin-2 gene expression profile using reverse transcription-polymerase chain reaction, X-gal staining and immunohistochemistry. IOP was measured via anterior chamber cannulation.

The researchers found that the bestrophin-2 gene plays a role in IOP generation by regulating the formation of aqueous humor. Specifically, disrupting the bestrophin-2 gene resulted in a significantly diminished IOP and altered sensitivity to drugs that affect the generation of aqueous humor.

While further studies are needed, the authors conclude that medications that inhibit bestrophin-2 function may be a viable approach for regulating IOP in patients with glaucoma.


Chinese Adults and Tilted Optic Discs
Eye
Published online April 4, 2008

You et al. reported findings from the population-based Beijing Eye Study in which the prevalence of tilted optic discs and the association with ocular and general parameters was examined.

Out of 4,324 participants for whom readable fundus photographs were available, the researchers identified tilted optic discs in 31 eyes of 23 individuals—extrapolated to approximately four out of 1,000 eyes of Chinese adults in Northern China. The tilted discs were associated with medium myopia, astigmatism, decreased visual acuity and visual field defects.


Biannual Mass Antibiotic Treatment to Eradicate Trachoma
Journal of the American Medical Association
2008;299:778–784

Comparing biannual treatment and annual treatment with mass antibiotics to determine whether ocular chlamydial infection can be eliminated from preschoolers, Melese et al. conducted a clinical trial in 16 rural villages in Ethiopia.

In the villages where all individuals one year of age or older were treated annually, the prevalence of infection in preschool children was reduced from a mean of 42.6 percent to 6.8 percent in 24 months. In the villages where residents were treated on a biannual basis, the infection was reduced from 31.6 percent to 0.9 percent at 24 months.
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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 is written by Lori Baker Schena and edited by Deepak P. Edward, MD.


THE YEAR IN REVIEW

The editors of the American Journal of Ophthalmology, Archives of Ophthalmology and Ophthalmology invite you to a review of interesting research published during the year that has immediate clinical relevance to the profession.

The Editors’ Choices Symposium
Monday, Nov. 11
Time: 10:15 a.m. to 12:15 p.m.
Fee: No charge


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