No abstract

Purpose The objectives of the present study were to evaluate whether investigator bias influenced the Convergence Insufficiency Symptom Survey (CISS) scores of children with normal binocular vision (NBV) in our original validation study, reevaluate the usefulness of the cut-off score of 16, and reexamine the validity of the CISS. Methods Six clinical sites participating in the Convergence Insufficiency Treatment Trial (CITT) enrolled 46 children 9 - <18 years with NBV. Examiners masked to the child’s binocular vision status administered the CISS. The mean CISS score was compared to that from the children with NBV in the original, unmasked CISS study and also to that of the 221 symptomatic CI children enrolled in the CITT. Results The mean (±SD) CISS score for 46 subjects with NBV was 10.4 (±8.1). This was comparable to that from our prior unmasked NBV study (mean = 8.1(± 6.2); p = 0.11), but was significantly different from that of the CITT CI group (mean = 29.8 ± 9.0; p < 0.001). Eighty-three percent of these NBV subjects scored less than 16 on the CISS, which is not statistically different from the 87.5% found in the original unmasked study (p = 0.49). Conclusions Examiner bias did not affect the CISS scores for subjects with NBV in our prior study. The CISS continues to be a valid instrument for quantifying symptoms in 9 to <18 year-old children and these results confirm the validity of a cut-point of ≥ 16 in distinguishing children with symptomatic CI from those with NBV.

Microbial keratitis (MK) is a corneal condition that encompasses several different pathogens and etiologies. While contact lens associated MK is most often associated with bacterial infections, other pathogens (fungi, Acanthamoeba species, etc) may be responsible. This review summarizes the risk factors, microbiology, diagnostic characteristics, and treatment options for all forms of contact lens-related MK.

Effects of font design and electronic display parameters upon text legibility were determined using a threshold size method. Participants' visual acuity (inverse of the minimum detection size, representing the threshold legibility for each condition) was measured using upper- and lowercase letters and lowercase words in combinations of 6 fonts, 3 font-smoothing modes, 4 font sizes, 10 pixel heights, and 4 stroke widths. Individual lowercase letters were 10% to 20% more legible than lowercase words (i.e., lowercase words must be 10%-20% larger to have the same threshold legibility). This letter superiority effect suggests that individual letters play a large role and word shape plays a smaller role, if any, in word identification at threshold. Pixel height, font, stroke width, and font smoothing had significant main effects on threshold legibility. Optimal legibility was attained at 9 pixels (10 points). Verdana and Arial were the most legible fonts; Times New Roman and Franklin were least legible. Subpixel rendering (ClearType) improved threshold legibility for some fonts and, in combination with Verdana, was the most legible condition. Increased stroke width (bold) improved threshold legibility but only at the thinnest width tested. Potential applications of this research include optimization of font design for legibility and readability.

Purpose To understand soft contact lens (SCL) and gas permeable lens (GP) wearers’ behaviors and knowledge regarding exposure of lenses to water. Methods The Contact Lens Risk Survey (CLRS) and health behavior questions were completed online by a convenience sample of 1,056 SCL and 85 GP wearers age 20–76 years. Participants were asked about exposing their lenses to water and their understanding of risks associated with these behaviors. Chi-square analyses examined relationships between patient behaviors and perceptions. Results GP wearers were more likely than SCL wearers to ever rinse or store lenses in water (rinsing: 91% GP, 31% SCL, p<0.001; storing: 33% GP, 15% SCL p<0.001). Among SCL wearers, males were more likely to store (24% vs 13%, p=0.003) or rinse (41% vs 29%, p=0.012) their lenses in water. Showering while wearing lenses was more common in SCL wearers (86%) than GP wearers (67%) (p<0.0001). Swimming while wearing lenses was reported by 62% of SCL wearers and 48% of GP wearers (p=0.027). Wearers who rinsed (SCL; p<0.0001, GP; p=0.11) or stored lenses in water (SCL; p<0.0001, GP p=0.007) reported this behavior had little or no effect on their infection risk, compared with those that did not. Both SCL (p<0.0001) and GP wearers (p<0.0001) perceived that distilled water was safer than tap water for storing or rinsing lenses. Conclusion Despite previously published evidence of Acanthamoeba keratitis’ association with water exposure, most SCL, and nearly all GP wearers regularly expose their lenses to water, with many unaware of the risk.