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Objectives: To determine whether Asian and white subjects differ in clinical signs or subjective symptoms in response to the use of different biguanide-preserved contact lens care solutions., Methods: Forty-two subjects (15 Asian and 27 white) wearing lotrafilcon B silicone hydrogel contact lenses used a preservative-free lens care solution bilaterally for 2 weeks, then used two biguanide-preserved solutions (solution 1: ReNu MPS; solution 2: AQuify MPS) contralaterally in randomly assigned eyes for 4 weeks. Comprehensive ocular surface examinations were performed and symptomatology questionnaires were administered every 2 weeks. Investigators were masked as to solution assignment during examinations, whereas subjects were not to avoid potential difficulties in compliance with the protocol., Results: With solution 1, most Asian and white subjects had grade 2 or greater corneal staining after 2 weeks (67% and 59%, respectively) and 4 weeks (60% and 67%, respectively). With solution 2, grade 2 or greater corneal staining occurred in 40% of Asians after 2 weeks and in 13% after 4 weeks, but in only 4% of whites after 2 weeks and 0% after 4 weeks. Whites reported significantly better average comfort (P=0.046) and less dryness (P<0.001) than did Asians., Conclusions: Asians and whites differ in both ocular response to the use of contact lens care solutions and in reporting subjective symptoms. Racial and ethnic differences should be considered when evaluating and treating contact lens patients in a clinical setting.

Purpose: To study the prevalence of and relation between refractive and corneal astigmatism in white school children in Northern Ireland and to describe the association between refractive astigmatism and refractive error., Methods: Stratified random clustering was used to recruit 1053 white children, 392 aged 6-7 years and 661 aged 12-13 years. Eye examinations included cycloplegic autorefraction and ocular biometric measures of axial length and corneal curvature., Results: The prevalence of refractive astigmatism (≥ 1 DC) did not differ significantly between 6- to 7-year-old children (24%; 95% confidence interval [CI], 19-30) and 12- to 13-year-old children (20%; 95% CI, 14-25). The prevalence of corneal astigmatism (≥ 1 DC) also did not differ significantly between 6- to 7-year-old children (29%; 95% CI, 24-34) and 12- to 13-year-old children (25%; 95% CI, 21-28). While levels of refractive astigmatism and corneal astigmatism were similar, refractive astigmatism was predominantly oblique (76%; 95% CI, 67-85, of 6- to 7-year-olds; 59%; 95% CI, 48-70, of 12- to 13-year-olds), but corneal astigmatism was predominantly with-the-rule (80%; 95% CI, 72-87, of 6- to 7-year-olds; 82%; 95% CI, 74-90, of 12- to 13-year-olds). The prevalence of refractive astigmatism was associated with increasing myopia and hyperopia., Conclusions: This study is the first to provide robust population-based data on the prevalence of astigmatism in white school children in the United Kingdom. The prevalence of refractive astigmatism and corneal astigmatism is stable between 6 and 7 years and 12 and 13 years, although this finding would need to be confirmed by prospective studies. There is a high prevalence of refractive and corneal astigmatism which is associated with ametropia.

Purpose: To investigate ethnic differences in corneal endothelia bleb formation and corneal swelling during contact lens wear under closed-eye conditions, with the use of lenses of varying oxygen transmissibilities (Dk/L) in Asian and non-Asian subjects, Methods: Asian and non-Asian contact-lens naive subjects were fitted with one of four different types of contact lenses at each 20-minute session. During lens wear, the eyelid was closed Endothelial bleb formation was determined by specular microscopy or confocal microscopy immediately on eye opening. Some Asian contact-lens naive subjects were asked to wear one of two types of lenses (Dk/L values of 24 and 175) on each eye for 1 hour Corneal swelling was determined immediately after opening of the eyes., Results: Asian subjects had a significantly higher degree of endothelial bleb formation than the non-Asian population for all closed eye conditions, p=0.0001. There was no significant difference in endothelial bleb formation between closed eves with or without lenses in the non-Asian population. There was a significantly higher degree of bleb formation with low Dk/L lenses, < or = 40, compared to high Dk/L lenses, > or = 110, in Asian subjects, p=0.0001., Conclusions: There is a significant difference between Asian and non-Asian subjects in the corneal response to stress. Under a closed eyelid only contact lenses with very high levels of Dk/L do not cause cornea stress in Asian patients.