Introduction: In the Philippines, essential eye care services are not easily accessible especially for those in lower income groups, putting public elementary school students at risk for underdiagnosis of problems in visual acuity. The objective of this investigation was to determine prevalence of undetected refractive errors among public elementary students using the Welch Allyn Spot™ Vision Screener. Methods : A cross-sectional design was used in this investigation to estimate the prevalence of uncorrected refractive errors in the first grade students in San Perfecto Elementary School using Welch Allyn Spot™ Vision Screener (Photoscreener). Eligible students who gave informed consent and assent answered a questionnaire and underwent an eye examination. The prevalence of undetected errors of refraction were computed for the sample population and for selected demographic variables. Results : Approximately one out of four students (24.53%) had errors of refraction, with the most common type being astigmatism (22.64%), followed by myopia (3.77%) and hyperopia (2.83%). Conclusion This study revealed a high prevalence of undetected refractive errors among school-age children, higher than current published data (5%) in the Philippines.
Cross-Sectional Studies ; Refractive Errors

Background: Pomacea canaliculata (Lamarck, 1819) is an invasive freshwater snail in the Philippines that damages crops but is consumed as food. It is known to harbor parasites, some of which are pathogenic to humans. Objectives: The objective of this study is to examine P. canaliculata individuals present in Metro Manila for parasite infection and identify the parasites and other organisms associated with the snail using molecular identification. Methodology: P. canaliculata were collected from rivers and marketplaces in Metro Manila. Individuals were crushed and digested in Ash's digestive fluid and observed under a microscope. Collected parasites were subjected to DNA barcoding of the COI gene for putative identification. Results: A total of 462 snails were gathered from 15 sites, eight of which were market areas that sourced the snails from outside Metro Manila. No known parasites were found. Two snails were found to contain insect larvae in the mantle (0.43% infection). The closest BLAST matches for the two insect larvae were the chironomid fly Nilodorum tainanus (91.0% identity) from a snail in Sucat, Muntinlupa, and another chironomid Parachironomus sp. (92.8% identity) found in a snail originally from Cavite and brought to Calumpang, Marikina. Conclusion This study is the first report of the presence of chironomids in Philippine P. canaliculata. This could have an impact on the allergenic status of these mollusks if consumed while containing these chironomids. The absence of infection of other medically important parasites is possibly due to the patchy distribution of the snails and few interactions with the definitive hosts of known parasites.
Chironomidae ; Diptera