Under-correction or full correction of myopia? A meta-analysis

PURPOSE: To compare the effect of full-correction versus under-correction on myopia progression. METHODS: A literature search was performed in PubMed, Scopus, Science Direct, Ovid, Web of Science and Cochrane library. Methodological quality assessment of the literature was evaluated according to the Critical Appraisal Skills Program. Statistical analysis was performed using Comprehensive Meta-Analysis (version 2, Biostat Inc., USA). RESULTS: The present meta-analysis included six studies (two randomized controlled trials [RCTs] and four non-RCTs) with 695 subjects (full-correction group, n = 371; under-correction group, n = 324) aged 6 to 33 years. Using cycloplegic refraction, the pooled difference in mean of myopia progression was - 0.179 D [lower and higher limits: -0.383, 0.025], which was higher but not in full correction group as compared to under correction group (p = 0.085). Regarding studies using non-cycloplegic subjective refraction according to maximum plus for maximum visual acuity, the pooled difference in myopia progression was 0.128 D [lower and higher limits: -0.057, 0.312] higher in under-correction group compared with full-correction group (p = 0.175). Although, difference in myopia progression did not reach significant level in either cycloplegic or non-cycloplegic refraction. CONCLUSIONS: Our findings suggest that, myopic eyes which are fully corrected with non-cycloplegic refraction with maximum plus sphere, are less prone to myopia progression, in comparison to those which were under corrected. However, regarding cycloplegic refraction, further studies are needed to better understand these trends

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Under-correction or full correction of myopia? A meta-analysis.

PURPOSE: To compare the effect of full-correction versus under-correction on myopia progression. METHODS: A literature search was performed in PubMed, Scopus, Science Direct, Ovid, Web of Science and Cochrane library. Methodological quality assessment of the literature was evaluated according to the Critical Appraisal Skills Program. Statistical analysis was performed using Comprehensive Meta-Analysis (version 2, Biostat Inc., USA). RESULTS: The present meta-analysis included six studies (two randomized controlled trials [RCTs] and four non-RCTs) with 695 subjects (full-correction group, n=371; under-correction group, n=324) aged 6 to 33 years. Using cycloplegic refraction, the pooled difference in mean of myopia progression was - 0.179 D [lower and higher limits: -0.383, 0.025], which was higher but not in full correction group as compared to under correction group (p=0.085). Regarding studies using non-cycloplegic subjective refraction according to maximum plus for maximum visual acuity, the pooled difference in myopia progression was 0.128 D [lower and higher limits: -0.057, 0.312] higher in under-correction group compared with full-correction group (p=0.175). Although, difference in myopia progression did not reach significant level in either cycloplegic or non-cycloplegic refraction. CONCLUSIONS: Our findings suggest that, myopic eyes which are fully corrected with non-cycloplegic refraction with maximum plus sphere, are less prone to myopia progression, in comparison to those which were under corrected. However, regarding cycloplegic refraction, further studies are needed to better understand these trends.

Anti-melanogenesis and anti-tyrosinase properties of Pistacia atlantica subsp. mutica extracts on B16F10 murine melanoma cells.

Pistacia atlantica (P. atlantica) subsp. mutica has been used in traditional medicine and is famous for its medicinal properties. The aim of this study was to evaluate the effect of methanol (MeOH), n-hexane, dichloromethane (CH2Cl2), n-butanol (BuOH), ethyl acetate (EtOAc), water extracts and essential oil of P. atlantica subsp. mutica on melanin synthesis and oxidative stress in B16F10 melanoma cell line. The B16F10 cells viability after treatment with increasing concentrations of different extracts of the plant (0.2-200 µg/mL) was measured using resazurin. Essential oil composition was identified by gas-chromatography-mass spectrometry (GC-MS) analysis and inhibitory effect on synthesis of melanin, mushroom tyrosinase activity, cellular tyrosinase, and oxidative stress were evaluated by the colorimetric and fluorometric methods. The data showed extracts at concentrations 0.2-200 µg/mL, did not show significant toxicity on melanoma cells but concentrations of 200 µg/mL of essential oil had cytotoxic effect. Pistacia atlantica subsp. mutica could inhibit the mushroom tyrosinase activity. Also the amount of melanin in B16F10 cells declined. In addition, the ability of P. atlantica subsp. mutica extracts in decreasing the amount of reactive oxygen species in melanoma cells revealed remarkable antioxidant activity. In addition, all concentrations of essential oil had no significant effect in this study. The melanogenesis inhibitory and antioxidant effects of P. atlantica subsp. mutica on B16F10 cells may suggest the potential whitening activity of the plant for using in dermatological skin care products and for prevention of skin aging in cosmetic industry.