METHODS: Cycloplegic (1% cyclopentolate) autorefraction was performed on 38, 811 children aged 5 and 15 in population-based samples at eight sites in the Refractive Error Study in Children (RESC). Refractions (right eye) were categorized as myopic (≤-0.5 D), emmetropic (>-0.5 to ≤+0.5 D), mildly hyperopic (>+0.5 to ≤+2.0 D and hyperopic (>+2.0 D).
RESULTS: At five sites (Jhapa - rural Nepal, New Delhi - urban India, Mahabubnagar - rural India, Durban - semi-urban South Africa and La Florida - urban Chile), there was <20% myopia by age 15. Mild hyperopia was the most prevalent category at all ages, except for Mahabubnagar where emmetropia became the marginally most prevalent category at ages 14 and 15. At the other sites (Gombak - semi-urban Malaysia, Shunyi - semi-rural China and Guangzhou - urban China), there was substantial (>35%) myopia by age 15. At these sites, mild hyperopia was the most prevalent category during early childhood, and myopia became the predominant category later. In Gombak district and Guangzhou, emmetropia was a minor category at all ages, with myopia increasing as mild hyperopia decreased. In Shunyi district, emmetropia was the most prevalent category over the ages 11-14.
CONCLUSION: Emmetropia was not the predominant outcome for refractive development in children. Instead, populations were predominantly mildly hyperopic or substantial amounts of myopia appeared in them. This suggests that mild hyperopia is the natural state of refractive development in children and that emmetropia during childhood carries the risk of subsequent progression to myopia.
METHODS: Thirty-five cases of highly myopic eyes with MHRD in 35 patients who underwent an initially successful vitrectomy with macular plug and were followed up for at least 3 years were reviewed. The anatomical outcomes were evaluated by fundus examination, fundus photographs and optical coherence tomography (OCT). Myopic features after the surgery were differentiated according to recommendations of the Meta-analysis of Pathologic Myopia (META-PM) Study Group. The best-corrected visual acuities (BCVAs) before and after surgery were analysed as the functional outcome. Main outcome measures time-course changes in BCVA and complications.
RESULTS: The mean patient age was 61.0 ± 11.4 years. The follow-up was 45.2 ± 8.6 months (ranged from 36 to 71 months). The mean axial length was 29.3 ± 1.2 mm. All eyes demonstrated attached retina, but 2 eyes (5.7%) developed reopened macular holes until the last follow-up. Complications of postoperative rhegmatogenous retinal detachment were detected in 2 eyes (5.7%) within 1 year and retina reattached after the secondary vitrectomy. Three cases (8.6%) of prolonged subretinal fluid lasting more than 1 year were detected but finally absorbed completely. Comparing 1-3 years postoperatively, myopic features showed significant progression of myopic maculopathy category (p = 0.035). Functionally, significantly improved BCVA could be maintained postoperatively between 6 months and 3 years. However, vision of 14 eyes (40.0%) worsened within 1-3 years postoperatively, and visual deterioration was associated with progression of myopic maculopathy (p = 0.004) and pre-existing disease of glaucoma (p = 0.006).
CONCLUSIONS: A vitrectomy combined with macular plug provided favourable outcomes in the long term, over the ≥3-year follow-up period.
METHODS: The Dy-based NPs were synthesized, and they were loaded onto commercial contact lenses. The loading content of the NPs and their release kinetics was determined based on the absorbance of their colloidal solution before and after soaking the contact lenses. The cytotoxicity of the NPs was evaluated, and the IC50 values of their antiamoebic activity against Acanthamoeba sp. were determined by MTT colorimetric assay, followed by observation on the morphological changes by using light microscopy. The mechanism of action of the Dy-based NPs against Acanthamoeba sp. was evaluated by DNA laddering assays.
RESULTS: The loading efficiencies of the Dy-based NPs onto the contact lens were in the range of 30.6-36.1% with respect to their initial concentration (0.5 mg ml-1 ). The Dy NPs were released with the flux approximately 5.5-11 μg cm-2 hr-1 , and the release was completed within 10 hr. The emission of the NPs consistently showed a peak at 575 nm due to Dy3+ ion, offering the possible monitoring and tracking of the NPs. The SEM images indicated the NPs are aggregated on the surface of the contact lenses. The DNA ladder assay suggested that the cells underwent DNA fragmentation, and the cell death was due most probably to necrosis, rather than apoptosis. The cytotoxicity assay of Acanthamoeba sp. suggested that Fe3 O4 -PEG, Fe3 O4 -PEG-Dy2 O3 , Dy(NO3 )3 .6H2 O and Dy(OH)3 NPs have an antiamoebic activity with the IC50 value being 4.5, 5.0, 9.5 and 22.5 μg ml-1 , respectively.
CONCLUSIONS: Overall findings in this study suggested that the Dy-based NPs can be considered as active antiamoebic agents and possess the potential as drugs against Acanthamoeba sp. The NPs could be loaded onto the contact lenses; thus, they can be potentially utilized to treat Acanthamoeba keratitis (AK).