Optometry and Vision Science (OVS) Announces Preview - March 2015



Coming in the March 2015 Optometry & Vision Science

Here are brief highlights.
The online and printed copy will be available early-March.
E-Publication Ahead-of-Print now available for all these articles at

Anthony J. Adams, OD, PhD, FAAO

Corneal Shaping with Overnight Hard Contact Lenses Slows Myopia

While numerous reports in Optometry & Vision Science (OVS), and elsewhere, have reported that othokeratology can slow myopia in teenagers and pre-teenagers, our authors have looked at seven selected published studies, which including axial length measures of the eye, in a meta analysis. They conclude, with even greater confidence, that orthokeratology does certainly slow myopia progression and retard the axial length growth of the eye.
Age and Myopia Prevalence Varies in Asia

  Most of us are aware of reports of a startling prevalence of myopia in Asia. Our authors performed a Meta analysis of 50 eligible studies, involving almost a quarter of a million individuals from birth to age 96 from 16 different Asian countries. Myopia was found to be most prevalent (96.5%) in 19 year old Koreans. There was no significant linear age group effect on the prevalence of myopia in the whole Asian population but there was a U-shaped relationship between both age and year of birth and the prevalence of myopia. The authors note that there is a large variation in the age-specific prevalence of myopia in Asia. They argue the analysis is essential to guide future eye health care, intervention and clinical management of myopia in Asia.
Astigmatism Worse Than Spherical Blur Regardless of Age?

Our authors studied two age groups (mean age 23 and mean age 57) in this comparison with a relatively small numbers of participants. They discovered that induced astigmatic errors reduced high contrast visual acuity twice as much as spherical blur in both groups. They suggest because of the inter-participant variation a study with 4 times as many participants might be needed to show any statistical difference between the two age groups.
Quality of a Child's Life with Uncorrected Refractive Error

Using focus group discussions with children, eye care practitioners and teachers, the authors found 8 themes emerged for this question. The authors propose that the current perceptions, beliefs and behavior exhibited in this south east India study can be used to formulate a target-specific awareness program and strategies to combat uncorrected refractive error, in addition to facilitating improved understanding and clinical management by eye care professionals.

Uncorrected Astigmatism Linked to School Readiness

Recent work has begun to probe a link between uncorrected refractive error and measures of academic readiness. The authors found an association between uncorrected astigmatism identified in a screening setting, and multiple domains of academic readiness in at-risk preschoolers. The finding has implications regarding the role of early vision screenings and comprehensive vision examinations in preventing reduced academic readiness in preschool children.
Eyelid Morphometry and Corneal Shape

Despite the possibility that eyelid morphometry may strongly influence corneal asphericity differences between Asian and non-Asian eyes, the authors found no such significant difference for sectors of the cornea. However some eyelid parameters including horizontal palpebral fissure width, upper and lower eyelid curvature, and lower eyelid slope showed some interaction with corneal shape parameters.

Silicone Hydrogel Daily Disposable Contact Lenses Compared

Our authors describe the clinical performance of three silicone hydrogel daily disposable contact lenses (SiHy DDCLs) in 51 asymptomatic and 53 symptomatic participants. Although there were some differences, all three lenses performed well. However, there was no difference between asymptomatic and symptomatic wearers with regard to ocular response and CL-related parameters, suggesting that SiHy DDCLs may be an excellent contact lens modality especially for the symptomatic patient.
Grading Staining From Both Live and Photographic Images

The authors compared live and photographic grades of corneal staining (including extent and type) of the same eyes, and found excellent repeatability of corneal staining grades of the images. However, digital still image grading of corneal staining significantly under-represented the amount of corneal staining observed through a slit lamp.

Scleral Lens Tolerance After Corneal Crosslinking for Keratoconus

In this prospective cohort, evaluations were made of 18 unilateral eyes in patients who underwent corneal crosslinking (CXL) and had been wearing scleral lenses before the procedure.  Sixty percent of eyes needed a new scleral lens fit and/or power change, but scleral lens tolerance after CXL appeared to be stable one year later.
Recurrence of Conjunctival Metaplasia After Pterygium Excision

The authors' study demonstrates that squamous metaplasia can recur even after non-complicated pterygium excision and limbal conjunctival autograft. The authors believe this might account for the high recurrence rate of pterygia.

Impact of Corneal Thickness on Cross Linking Success

Although thinner corneas dehydrated faster than thicker corneas, corneal crosslinking (CXL) was safe and effective in all study groups. The authors caution that it is important that keratoconus patients are carefully monitored during treatment to avoid damage by ultraviolet-A light. The results of the hypoosmolar riboflavin CXL study group are especially promising for young individuals with advanced progressive keratoconus.
A Novel Mutation in Congenital Nuclear Cataract

The authors applied exome sequencing and Sanger sequencing to identify a genetic defect in a Chinese Han pedigree with congenital nuclear cataract.  These findings suggest exome sequencing is powerful and cost-effective for discovering mutations in disorders with high genetic and clinical heterogeneity, even in small pedigrees.

Ocular Biometrics of Family Members

Low coherence interferometry was used to compare biometric parameters among normal siblings and those affected by varying degrees of angle closure ranging from primary angle closure suspect to angle closure glaucoma. The best predictor of angle closure was anterior chamber depth though corneal thickness, lens thickness, vitreous depth, and axial length all differed from normal eyes in the progression through to angle closure glaucoma.
Yes and No on Corneal Thickness and IOP

While the authors found central corneal thickness was significantly related to IOP, it was not related to diurnal IOP fluctuations in a relatively large group of non-glaucomatous participants.

Self Restriction of Driving in Glaucoma Patients

Our authors' study of glaucoma patients indicates that driving self-restriction, in one or more ways, is associated with a lower prevalence of motor vehicle collisions in Japanese men, but not women.

Low Vision Care by Canadian Optometrists

About 460 Canadian optometrists were surveyed across the country about their provision of care for low vision (LV) patients. This is the first such Canadian survey and it shows that most optometrists are involved with LV care. The authors believe that optometrists can improve access to low vision care by actively screening for patients with low vision and by being compensated adequately for their work.

Not All Adult Amblyopes Are the Same

Multifocal cortical VEP latencies were significantly more delayed in anisometropic eyes than in strabismic eyes, consistent with anisometropic and strabismic amblyopes having different cortical abnormalities. However, not surprisingly, our authors confirm that the retina is normal; peripapillary retinal nerve fiber layer and macular thickness were not statistically different in amblyopes from control participants.

Retinal Vessel Tortuosity Abnormal In Diabetic Eyes

Because diabetic eye disease is a leading cause of vision loss, our authors evaluated the associations between retinal vessel appearance and other health factors in veterans with diabetes. They found increased retinal arteriole tortuosity is associated with diabetic retinopathy and increased cholesterol levels. They recommend future studies examining tortuosity should focus on arterioles since tortuosity of venules is difficult to grade consistently.

New and Improved Bland-Altman Reliability Tool

Bland-Altman Analysis is a popular statistical tool amongst eye researchers and many OVS reviewers and Topical Editors ask authors to apply the tool. Bland-Altman 95% Limits of Agreement (LoAs) are used to estimate the range of measurement agreement, or measurement repeatability. Because LoAs can, themselves, be unreliable estimates especially for small sample sizes, it can be useful to calculate confidence intervals for LoAs. Our author describes a new technique for calculating exact confidence intervals for LoAs for any sample size, assuming normally distributed data. The technique is an improved tool for researchers.