Researchers from Korea investigated risks and protective factors associated with pediatric dry-eye disease in relation to smartphone use rate, categorized by region and age.

They enrolled 916 children in the study and performed an ocular exam that included a slit lamp exam and tear breakup time. Researchers also administered a questionnaire to children and their families, inquiring about video display terminal use and outdoor activity. DED was defined based on the International Dry Eye Workshop guidelines, looking specifically at punctate epithelial erosion and short tear breakup time. Children were divided into: DED vs. control; urban vs. rural; younger grade (1st to 3rd) vs. older grade (4th to 6th).

A total of 6.6 percent of children were included in the DED group; 8.3 percent of children in the urban group were diagnosed with DED compared to 2.8 percent in the rural group (p=0.03). The rate of smartphone use was 61.3 percent in the urban group and 51 percent in the rural group (p=0.04). In total, 9.1 percent of children in the older-grade group were diagnosed with DED compared to 4 percent in the younger-grade group (p=0.03). The rate of smartphone use was 65.1 percent in older-grade children and 50.9 percent in younger-grade children (p<0.001). The mean daily duration of smartphone use was longer in the DED group than controls (p< 0.001, OR= 13.07), and the mean daily duration of outdoor activities was shorter in the DED group than controls (p<0.01, OR=0.33). After cessation of smartphone use for four weeks in the DED group, both subjective symptoms and objective signs had improved.

While smartphone use in children was strongly associated with pediatric DED, outdoor activity appeared to be protective against it. Older-grade students in urban environments had DED risk factors and a short duration of outdoor activity time. Therefore, the researchers say, close observation and caution are needed when older children in urban areas use smartphones, as they are more likely to develop pediatric DED.

BMC Ophthalmol 2016;16:188
Moon J, Kim K, Moon N.

IOL Powers in Aging Eyes
Because age-related changes in lens elasticity and ciliary muscle contractility can affect how ocular parameters respond to cycloplegia and intraocular lens power measurements calculated by formulas using anterior chamber depth, lens thickness or white-to-white for effective lens position prediction can therefore vary. With that in mind, researchers from Turkey sought to investigate changes in ocular parameters and IOL power calculations attributable to cycloplegia in aging eyes.

In this cross-sectional study, looking at 38 pre-presbyopic and 42 presbyopic eyes, researchers measured pupil diameter, radius of corneal curvature values, central corneal thickness, WtW, ACD, LT and axial length, both before and after cycloplegia. Using SRK/T, Holladay 2 and Haigis formulas, researchers performed IOL power calculations. To pinpoint the effect of cycloplegia, researchers recorded refractive predictions in pre- and post-dilation
conditions using the same IOL power calculations, even if post-dilation IOL power calculations had changed.

With cycloplegia, pupil diameter changed significantly more in presbyopic eyes (p=0.001). Central corneal thickness decreased in pre-presbyopic eyes (p=0.048), whereas WtW increased in presbyopic eyes (p=0.02). In both groups, ACD and LT changed significantly (p<0.001). IOL power calculations using the Holladay 2 formula differed in pre-presbyopic eyes (p=0.042), and refractive predictions with the Holladay 2 and Haigis formulas differed significantly in pre-presbyopic eyes (p=0.043 and p=0.022, respectively).

Considering these results, the investigators recommend that surgeons consider the effect of cycloplegia on refractive prediction errors and IOL power calculations determined with Haigis and Holladay 2 formulas, especially in pre-presbyopic eyes.

Am J Opthalmol 2017;173:76-83
Özyol P, Özyol E, Baldemir E.

Clinical Activity of CNV in AMD
Researchers from Boston sought to characterize the features of choroidal neovascularization in neovascular age-related macular degeneration using spectral-domain optical coherence tomography angiography and to determine whether OCTA can be used to monitor clinical activity of CNV.

In the observational, retrospective, consecutive case series, researchers looked at patients with a clinical diagnosis of neovascular AMD who underwent OCTA imaging. The patients were imaged between August and October 2014 at the New England Eye Center at Tufts Medical Center. The investigators used OCTA software to delineate the outer retina and subretinal pigment epithelial space, if applicable.

The researchers defined clinical activity as the presence of one of the following: a new diagnosis of neovascular AMD with active leakage on FA and/or the presence of fluid on OCT, or a previous diagnosis of neovascular AMD; vision loss greater than or equal to one Snellen line; presence of new hemorrhage on fundus examination; recurrent intraretinal or subretinal fluid on structural OCT B-scans; persistent or increased intraretinal or subretinal fluid on structural OCT B-scans despite treatment; and presence of leakage on FA if performed on the same day as OCTA.

OCTA revealed CNV in 28 eyes (62.2 percent) while 17 eyes (37.8 percent) didn’t demonstrate CNV vessels. The researchers classified the CNV as well-circumscribed in 12 eyes (42.8 percent) and poorly circumscribed in 16 eyes (57.2 percent). Twenty-two eyes with CNV seen by OCTA were clinically active, whereas six eyes with visible CNV on OCTA were clinically inactive. Of the 17 eyes that didn’t have evidence of CNV on OCTA imaging, 14 were clinically inactive and three were clinically active. Presence of CNV on OCTA correlated with clinical activity, and absence of CNV correlated with inactivity (p<0.0001).  

OCTA is a noninvasive imaging technique that can be used to visualize blood flow comprising CNV. It detects CNV vessels in some, but not all eyes with neovascular age-related macular degeneration. Although the presence or absence of CNV vessels on OCTA was highly correlated with clinical activity of CNV, the morphologic appearance of CNV on OCTA didn’t have significant correlation with clinical activity in this study.

Retina 2016;36:2265-2273
Liang M, De Carlo T, Baumal C, Reichel E, et al.