Optometry and Vision Science (OVS) Announces Preview - February 2013


Coming in the February 2013 Optometry & Vision Science

Here are brief highlights.
The online and printed copy will be available early-February.
E-Publication Ahead-of-Print now available for all these articles at http://journals.lww.com/optvissci

Anthony J. Adams, OD, PhD, FAAO
Do all brain injuries, including blast injuries, produce the same kind of vision loss?  
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Visual deficits are common following traumatic brain injury, highlighted by blast related brain injury to military personnel. Our authors found no differences in blast-related vision loss than for other brain injury mechanisms. The two exceptions were that light sensitivity was more common following a blast, and saccadic deficits more common in other traumas. Comprehensive eye examinations are recommended following even mild traumatic brain injury.

A glass ceiling for rigid contact lens fitting prevalence?  
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From their international survey in 40 countries the authors document that rigid contact lens prescribing is in decline between 2007 and 2011, but still represents around 10% of all contact lenses fitted worldwide. Compared with soft lenses, rigid lens fits had the following characteristics: older age, less spherical and toric fits, more bifocal fits, less frequent replacement, and less part-time wear. They conclude it is likely that rigid lenses will remain a viable, albeit increasingly specialized, form of vision correction.

A 'cocktail' amoebicidal for multipurpose contact lens disinfection  
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The authors demonstrate that the cationic peptide protamine, in combination with the disinfectant polyhexamethyl biguanide, can effectively kill trophozoites and cysts of Acanthamoeba sp. This combination does not induce encystment of the Acanthamoeba. This combination may be useful in multipurpose disinfecting solutions.

Can you measure IOP reliably over soft contact lenses?  
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The authors showed good reliability of intraocular pressure (IOP) and ocular pulse amplitude (OPA) using the Dynamic Contour Tonometer (DCT) over contact lenses. They used varying thickness profiles and different soft materials and found no clinically significant differences.

Does an "eye-size mechanism" facilitate myopia development in children?  
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The authors found early restraint of axial elongation in response to plus lenses increases the subsequent response to interrupted hyperopia in tree shrews. In those animals, unlike other animals, 2 hours of relief from imposed hyperopia did not prevent myopia development. They conclude that there is, consistent with other reports, an eye size mechanism operating in eyes that have experienced prior axial length constraint with lens treatments.

How far in peripheral retina is refractive error relevant for myopia development?  
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It is often considered that a pattern of relative peripheral hypermetropia predisposes to the development of myopia. The authors' finding of a considerable portion of emmetropes with a distinct peripheral retina refractive pattern suggests it is unlikely that refraction at visual field angles beyond 40° from fixation contributes to myopia development.

UV exposure, not light exposure, stabilizes myopia progression?  
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A few reports suggest that outdoor activity decreases the risk of myopia in children and may offset the myopia risk associated with prolonged near work. Our authors explored the relationship between near work, indoor illumination, daily sunlight and ultraviolet (UV) exposure in emmetropic, stable myopic, and progressing myopic university students, Only UV exposure (measured with a polysulphone UV dosimeter) was significantly different across the 3 groups with stable myopes experiencing significantly greater UV exposure. This suggests some 'myopia protection'.

Can reading chinese text induce myopia?  
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Inaccurate accommodation during near work and subsequent accommodative hysteresis may influence myopia development. An untested theory is that Chinese children are prone to these accommodation characteristics because of differences in reading chinese text. In Singaporean children, reading chinese text caused smaller accommodative lags than reading english text, but the small differences were not clinically significant. However myopic children had significantly greater near work induced transient myopia than emmetropic children for both text forms.

A new device for fundus perimetry  
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The assessment of fixation ability in patients with low vision can help determine the course of management. When measuring the function in patients with low vision, there is the inherent assumption that the fixation ability is sufficient for testing, when in fact the patient may have eccentric or unstable fixation. The authors developed a relatively simple scanning laser imaging device that can present stimuli while viewing an image of the retina using dim, near infrared light. By identifying and preventing false positives due to eye motion the variability of perimetric data was reduced.

Comparing 3 different logMAR visual acuity charts  
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The authors study found that Landolt C charts resulted in worse VA estimates compared to letter and tumbling E charts in both young adults and visually impaired subjects with diabetic retinopathy (DR). The differences between chart measures were more pronounced in DR patients, who had worse visual acuity.

IOP reduction after cataract surgery in primary open angle glaucoma  
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Intraocular pressure (IOP) decreases after cataract surgery in patients with or without glaucoma. Our authors identified preoperative factors associated with postoperative IOP reduction in patients with primary open angle glaucoma (POAG) who had uncomplicated cataract extraction at a VA Medical Center. Those with higher preoperative IOP tended to have greater postoperative IOP reduction. Patients with IOP in low teens tended to have no reduction or even a mild increase in postoperative IOP.

Vision outcomes of cataract surgery in developing and developed countries  
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Cataract surgery by trained surgeons in mass campaigns in developing countries produce comparable visual function outcomes to developed countries when standardized protocols are followed. A comprehensive monitoring of the outcomes appears essential for optimal results.

Suppression in patients with high anisometropia  
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With a rapid technique for measuring suppression using a dichoptic signal/noise task, the authors report a modification that allows accurate measurements in amblyopic patients with high levels of anisometropia. The modification was necessary as aniseikonic image size differences between the two eyes can provide a cue for signal/noise segregation and therefore influence suppression measurement.

Co-infection with Pseudomonas and Acanthamoeba in a contact lens user  
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Both Pseudomonas aeruginosa and Acanthamoeba are potentially devastating causes of microbial keratitis. The authors’ clinical case highlights the importance of considering the possibility of concurrent infections in cases with contact lens related keratitis.

Recognizing ocular consequences of radiation therapy for ocular lymphoma  
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Ocular lymphoma, though not commonly encountered, is one of the few cancers optometrists are uniquely qualified to identify with a slit lamp on routine examination. It requires thorough evaluation and careful staging. The somewhat unique element to this case was the patient's concurrent diagnosis of glaucoma. The patient’s ocular pain was the result of radiation-induced periorbital and conjunctival inflammation and radiation induced dry eye. Patients undergoing radiation therapy for ocular lymphoma are likely to develop a significant amount of ocular surface irritation, dry eye and inflammation.

What's new and what's not in Fabry disease?  
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Fabry disease is an X-linked genetic disorder caused by accumulation of unmetabolized glycolipids in tissues throughout the body. Progressive lipid storage can cause widespread ischemia, irreversible organ damage and early death. A distinctive keratopathy is prominent and facilitates early diagnosis with correlation of systemic manifestations, symptoms, and personal/ancestral health histories. As illustrated in this Fabry proband enzyme replacement therapy, new screening methods and emerging treatment strategies prove the benefits of early intervention.