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Volume 12, Number 16
Monday, April 16, 2012
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In this issue: (click heading to view article)
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######### Progressive Local Nerve Fiber Loss Following Disc Hemorrhages in Glaucoma Patients

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######### Exudative AMD and PCV in the ARMS2/HTRA1 Locus
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######### Correlation Between Sleep Apnea and Risk of RVO
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######### A Closer Look at the Design and Analysis of Ophthalmic Randomized Controlled Trials
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http://ecatalog.alcon.com/PI/Nevanac_us_en.pdf





Progressive Local Nerve Fiber Loss Following Disc Hemorrhages in Glaucoma Patients

German investigators examined whether optic disc hemorrhages (ODH) lead to significant loss of nerve fibers at the lesion site over time and whether such a loss is reflected by visual field defects corresponding to the affected nerve fiber bundle.

In this retrospective study of 10 sequential glaucoma patients (ten eyes) with ODH, they used high-resolution OCT circular scans (Spectralis HRA + OCT) to determine peripapillary retinal nerve fiber layer (RNFL) thickness at the time of ODH presentation and at follow-up visit between 3 and 6 months. They also analyzed corresponding perimetric data for global (mean defect, MD) and localized progression of visual field defects.

According to the investigators, ODH were mostly located in the inferior quadrant as determined clinically and from fundus photographs. They also reported that iterative OCT imaging revealed a significant RNFL reduction in the affected quadrant relative to the respective quadrant in the fellow eye (RNFL change = –2.25 ± 2.69 µm vs. 0.75 ± 2.78 µm, p = 0.01) within 120 ± 43 days. However, only three cases presented with new/progressive nerve fiber bundle defects corresponding to the lesion site within the given follow-up period.

To conclude, ODH lead to a significantly higher RNFL loss at the lesion site relative to the overall structural progression in glaucoma patients. However, this focal change is not generally reflected by respective nerve fiber bundle defects in the time frame investigated.

SOURCE: Kernstock C, Dietzsch J, Januschowski K, et al. Optical coherence tomography shows progressive local nerve fiber loss after disc hemorrhages in glaucoma patients. Graefes Arch Clin Exp Ophthalmol. 2012;150(4):583–587.










Exudative AMD and PCV in the ARMS2/HTRA1 Locus

The authors of the following Chinese study sought to differentiate the associations of exudative age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) with the ARMS2/HTRA1 locus. They found a strong and consistent association of the ARMS2/HTRA1 locus with both exudative AMD and PCV, suggesting the two disorders share, at least partially, similar molecular mechanisms.

They sequenced the entire ARMS2 sequence and genotyped HTRA1 rs11200638 in 568 unrelated Chinese individuals: 156 exudative AMD patients, 164 PCV patients and 248 controls. The authors also performed a meta-analysis to examine the effects of rs10490924 and rs11200638 at the ARMS2/HTRA1 locus in PCV.

In total, they identified 31 polymorphisms in ARMS2. They also observed significant associations with both exudative AMD and PCV in 11 of them and HTRA1 rs11200638, with different genotypic distributions between exudative AMD and PCV (p<0.001). The study authors reported that after adjusting for rs11200638, ARMS2 rs10490924 remained significantly associated with exudative AMD (p=0.011), but not with PCV (p=0.077). Moreover, meta-analysis showed consistent allelic associations of rs10490924 and rs11200638 with PCV in different study populations.

In conclusion, different effect sizes indicate the existence of additional genetic and environmental factors affecting them to different extents.

SOURCE: Liang XY, Lai TY, Liu DT, et al. Differentiation of exudative age-related macular degeneration and polypoidal choroidal vasculopathy in the ARMS2/HTRA1 locus. Invest Ophthalmol Vis Sci. 2012; Apr 6. [Epub ahead of print].








Correlation Between Sleep Apnea and Risk of RVO

Researchers aimed to explore the relationship of sleep apnea and the subsequent development of retinal vein occlusion (RVO). They conducted a retrospective nonrandomized, matched-control cohort study using the Taiwan National Health Insurance Research Database and found that sleep apnea may be an independent risk factor for RVO.

From 1997 through 2007, they identified newly diagnosed sleep apnea cases in the database and selected a control group without sleep apnea, matched for age, gender and comorbidities, for comparison. Additionally, they followed the 2 cohorts and observed and the occurrence of RVO.

The researchers noted that of the 35,634 sampled patients (5,965 sleep apnea patients vs 29,669 controls), 52 (0.15%) experienced RVO during a mean follow-up period of 3.72 years, including 13 (0.22%, all branch RVO) from the sleep apnea cohort and 39 (0.13%, 39 branch RVO and 10 central RVO) from the control group. Kaplan-Meier analysis revealed the tendency of sleep apnea patients toward RVO development (p = .048, log-rank test). Furthermore, patients with sleep apnea experienced a 1.94-fold increase (95% confidence interval, 1.03 to 3.65; p = .041) in incident RVO, which was independent of age, gender and comorbidities.

SOURCE: Chou KT, Huang CC, Tsai dC, et al. Sleep apnea and risk of retinal vein occlusion: a nationwide population-based study of Taiwanese. Am J Ophthalmol. 2012; Apr. 1 [Epub ahead of print].

 



http://corporate.eyemaginations.com/healthcare-solutions/eyecare/luma/pricing






A Closer Look at the Design and Analysis of Ophthalmic Randomized Controlled Trials

In ophthalmic randomized controlled trials (RCTs), each subject may have 2 potential data points (i.e., eyes) contributing to the clinical trial; therefore, various study designs may arise requiring different statistical tools. This study aimed to assess the appropriateness of study design, statistical tools used and reporting of results in ophthalmic RCTs.

In this systematic review of 69 ophthalmic RCTs published in 4 major general clinical ophthalmology journals in 2009, the study design, sample size calculation, statistical analysis and reporting methodology of all RCTs were assessed. For the main outcome measure, the study design of each article under review is evaluated.

The most common study design was a one-eye design (48%). Within this group, only half described the method of selecting the study eye, among which 5 chose the study eye by random selection. In the remaining trials, there were paired-eye design (13%), subject design (19%) and two-eye design (19%). Among the 13 two-eye design studies, 4 allocated both eyes of the subject to the same group, 4 allocated the eyes to different groups, and 4 did not restrict the allocation. None of these studies adjusted for the clustering effect in sample size calculation. Only 5 studies used statistical methods adjusting for nonindependence.

There is currently substantial heterogeneity in the quality among published ophthalmic RCTs in terms of proper use of study design, sample size calculation, randomization method and statistical tools. Future ophthalmic researchers are suggested to consult a statistician and to follow some guidelines such as the CONSORT statement when performing an RCT to improve further the quality of clinical trial.

SOURCE: Lee CF, Cheng AC, Fong DY. Eyes or subjects: are ophthalmic randomized controlled trials properly designed and analyzed? Ophthalmol. 2012;119(4):869–872.











 




  • OMEROS BEGINS PATIENT ENROLLMENT IN SECOND PHASE 3 CLINICAL TRIAL OF OMS302. Patient enrollment has begun in Omeros Corporation's second Phase 3 clinical trial evaluating OMS302 in intraocular lens replacement (ILR) surgery. OMS302 is added to standard irrigation solution used during ILR procedures to maintain intraoperative mydriasis and reduce postop pain. This trial will enroll roughly 400 patients undergoing cataract surgery or refractive lens exchange and will evaluate the same efficacy and safety measures as the earlier successful Phase 2b and 3 clinical trials. The company expects data in the second half of 2012. For more information, visit www.omeros.com.
  • COOPERVISION RECEIVES SPECIAL 510(k) CLEARANCE ON AVAIRA TORIC CLs. The FDA has granted a Special 510(k) clearance for CooperVision's Avaira Toric two-week silicone hydrogel contact lenses for astigmatism. The company will re-launch the lens with shipments available for select distribution beginning early May 2012. Read more here.
  • OPTIMEDICA'S CATALYS PRECISION LASER SYSTEM RECEIVES CE MARK FOR CORNEAL INCISIONS. OptiMedica Corp.'s Catalys Precision Laser System has been CE mark approved for creating single-plain and multi-plane arc cuts/incisions in the cornea during cataract surgery. According to the company, the approval adds new utility to the next generation laser cataract surgery system, which was previously CE mark approved and FDA market cleared for capsulotomy and lens fragmentation. Additional information can be found on OptiMedica's website.
  • MCDONALD NAMED INAUGURAL VISIONARY WOMAN AWARD WINNER. Marguerite McDonald, MD, has been named as recipient of Ophthalmic Women Leaders' (OWL's) 2012 Visionary Woman Award. OWL President Jan Beiting comments, “Along with being noted for performing the first laser vision correction procedure and elected as the first female president of ASCRS and ISRS, [Dr. McDonald] takes an active role in advancing women's careers through mentoring. She is a trailblazer in every way.” This is the first year for the award, which will be presented at OWL's signature reception on Monday, April 23rd at the Hilton Chicago. Details and registration for the Visionary Woman Award reception and other OWL programs can be found here.




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