Optometry and Vision Science (OVS) Announces Preview - January 2015
Coming in the January 2015 Optometry & Vision Science
Here are brief highlights. The online and printed copy will be available early-January. E-Publication Ahead-of-Print now available for all these articles at http://journals.lww.com/optvissci
Anthony J. Adams, OD, PhD, FAAO Editor-in-Chief
Recommended Practices for 3 to 6 yr-old Children’s' Eye Health
This is the first of a series of three papers providing recommendations on screening eye health for 3 to 6 year olds. The recommendations from an interdisciplinary panel, (The National Expert Panel (NEP) to the National Center for Children's Vision and Eye Health, are sponsored by Prevent Blindness, and are funded by the Maternal and Child Health Bureau of the Health Resources and Services Administration, United States Department of Health and Human Services. In this first paper, the Panel outline recommended practices and testing methods, and promise to provide technological updates at: http://nationalcenter.preventblindness.org
Data Reporting Measures for 3 to 6 yr-old Children’s' Eye Health
The same Panel, noted in the previous preview, reviewed existing literature and used a consensus approach to outline recommended performance data measures and definitions for the vision of 3 to 6 year olds. An important component of their report was defining rates of children "who completed a vision screening in a medical or community setting using a recommended method, or received an eye examination by an optometrist or ophthalmologist at least once between the ages of 36 to 72 months.
A Proposed Integrated Data System for 3 to 6 yr-old Children’s' Eye Health
The National Expert Panel to the National Center for Children's Vision and Eye Health, comprised of leading professionals in optometry, ophthalmology, pediatrics, public health, and related fields developed recommendations for improvements that can be made in the public health infrastructure supporting early detection of children's vision problems. They recommend an integrated vision data system intended to enhance eye health for young children at three different levels: (1) the child level, (2) the health care provider level, and (3) an epidemiological level, for local, state and national application.
How do children and adolescents with autism compare to typically developing peers in their ability to complete eye and vision tests? The authors compared 9-17yr-old patients with autism spectrum disorder (ASD) to the age-matched controls in their ability to complete tests of visual acuity, refraction, convergence, stereoacuity, ocular motility, and ocular health. A psychologist using DSM-IV-TR criteria, review of previous evaluations, and parent responses on the Social Communication Questionnaire screened ASD participants for status/eligibility. They concluded there was little difference between the groups in eye examination ease; most ASD can complete most tests.
Daily Disposable Contact Lenses Versus Spectacles for Teenagers
Using one brand of daily disposable contact lenses (CL) for first-time wearers, our authors conclude that these CL are a viable alternative to spectacles in terms of quality of life, without negatively impacting eye health. Ninety seven teenagers participated, randomly assigned to either CL or spectacles, were followed clinically for 6 months and completed subjective QoL measures using the Pediatric Refractive Error Profile (PREP) and QoL Impact of Refractive Correction (QIRC) questionnaire.
Refractive Errors in Children in Equatorial Guinea
425 school children (between 6 and 16 years) from Malabo (Island of Bioko) in Equatorial Guinea (western-central Africa) had cycloplegic autorefraction measured. There was low (10%) prevalence of myopic refractive error though it was slightly higher in private than public schools. Corneal curvature was not age-dependent.
Refraction Service Barriers in Mozambique
Uncorrected refractive error remains a leading cause of visual impairment across the globe and Mozambique is no exception. A community-based cross-sectional study using two-stage cluster sampling was conducted by our authors in Nampula, Mozambique. For those 1,087 with lowered acuity (out of 4,601), the barriers of accessing refractive services were based on their perceptions. For more than 50% cost was the most frequently cited barrier. Other barriers identified included lack of felt need (20%), distance to travel (15%) and lack of awareness (13%).
Improved Perimetry Using Structural Information
The authors use a strategy, Structure Estimation of Minimum Uncertainty (SEMU), which depends on an individual's retinal nerve fiber layer thickness data to predict the suprathreshold stimulus levels for testing. It then alters the prior probability of a Bayesian test procedure. The performance of SEMU was assessed using computer simulation and compared to standard procedures. On average, simulations show that using RNFL information to guide stimulus placement in a perimetric test procedure gave better accuracy, improved precision, and decreased test duration for patients with less than a 15% false positive rate.
Inter-Measurement Instrument Variability a Problem?
An inherent limitation in identifying disease progression is the margin of error introduced by diagnostic instruments. Computer tomography is commonly used to scan the retinal nerve fiber layer for subtle glaucomatous changes. The authors study of over 200 participants suggests that such variability would not be an issue in detecting glaucomatous progression in their peripapillary RNFL measures using the high definition Cirrus HD-OCT.
Gender Differences in Impact of Oxybuprocaine Drops (0.4%) on Corneal Thickness?
Apparently yes, oxybuprocaine anesthetic eye drops induced significant corneal thickness increases in females but not in males. This was true in the inferior and nasal corneal sites in female participants following the application of the drops.
Head Position and IOP
Sometimes IOP needs to be measured while the patient is lying down. Our authors found that the lateral decubitus posture of the body resulted in higher IOP in the lower eyes compared with the fellow eyes of healthy young subjects, regardless of the height of a pillow. Low head position elevates the IOP of the lower of the two eyes. Proper adjustment of the height of a pillow may help mitigate IOP elevations resulting from lying on the side with a low or no pillow.
A Question of Systemic Cancer Treatment Effects on Otherwise Normal Eyes
Patients who underwent chemotherapy regimen because of colon, lung and breast cancer between years 2010-2012 were administrated intravenous bevacizumab in three different dosages (5-7.5-15 mg/kg/day) at two or three week intervals and a total of 6-18 courses. Evaluations included best-corrected visual acuity (BCVA), color vision assessment and ocular examinations with optical coherence tomography. They conclude that repeated doses of systemic bevacizumab did not cause a clinically deleterious effect on healthy eyes of cancer patients.
What Drives Vergence for Single Binocular Vision?
Vergence eye movements serve to align both eyes on the same target for single binocular vision. When a target moves in the midsagittal plane, symmetrical vergence eye movements occur. In contrast, for targets located to one side of the midsagittal plane, asymmetrical vergence movements are induced. Some evidence has shown a single binocular control mechanism (Maxwell and Schor) for vergence, while others endorse the role of a strong monocular component. Our authors' results support a single binocular control mechanism for vergence control for binocular vision.
Best Way to Measure Peripheral Defocus in Myopia?
Myopia development has been associated with hyperopic blur in the peripheral retina. Our authors use retinal shape measures using Spectral Domain Optical Coherence Tomography to measure the eye's shape in the periphery. They find consistent differences between emmetrope/hyperopes and myopes nearer to the fovea (at 5 degrees eccentricity) than previously reported. While autorefraction does give a direct defocus measure in the periphery, the authors clearly feel there may be a place for outcome measures in myopia development to use eye shape measures this way.
Reducing Myopia with Removal of a Corneal Lenticule
Amid many approaches to reducing myopia, a relatively new small incision approach removes a 'lenticule' from the stroma. In a 12- month study, a small incision lenticule extraction was a promising corneal refractive procedure to correct myopia. The authors also reported good safety, efficacy, stability, and predictability. At 12 months, 90% of eyes were within +/-0.5D of the intended refractive target. The uncorrected visual acuity was 20/20 or better in 83% of eyes, with 98% of eyes having the same best-corrected visual acuity.
Do Cone Photoreceptor Ratios Impact Myopia Development?
The causes of myopia are on all clinician’s minds. Recently there has been a suggestion that the long wavelength sensitive (LWS) to middle wavelength sensitive (MWS) cone ratio in the retina is associated with myopia. Our authors could find little to support this suggestion in their clever human electrophysiological (mfVEP) pilot study, but they concede that a much larger longitudinal study of myopia in persons with known cone ratios is required to convincingly address this interesting suggestion.
Retinal Vaso-Occlusive Disease Needs Demystifying
Not all retinal vaso-occlusive phenomenon can be completely attributed to a central retinal vein or artery occlusion. In a patient with POAG and sudden unilateral vision loss, our authors found no objective diagnostic testing that revealed a cause for the patient's vision loss or relative afferent pupillary defect. This combined with the complete recovery of vision and resolution of the relative afferent pupillary defect underscores a lack of comprehensive understanding of retinal vaso-occlusive disease.
New Insights on Focal Choroidal Excavation (FCE)
Using spectral-domain optical coherence tomography (SD-OCT), our authors present 2 cases that provide quite novel insight on the increasingly recognized inflammatory chorioretinal disorder of focal choroidal excavation (FCE).
What's New in Retinal Diagnosis?: Imaging as Injection-Free Angiography
Our authors highlight the promising multispectral imaging (MSI) applied to enhance visualization of individual retinal layers, including deep retinal structures. This is the first report using MSI for the detection of polypoidal choroidal vasculopathy (PCV). The MSI can reveal highly defined hyperreflective polyp-like structures in the longer wavelength images. The noninvasiveness, simplicity and effectiveness of MSI in diagnosing PCV should be attractive to clinicians.