RESUMO
Purpose: To investigate the physical properties of commercially available multipurpose soft contact lens solutions in Ghana. Methods: pH (Kelilong ICL-099 pH meter, China), osmolality (OSMOMAT 3000, GONOTEC, Germany), surface tension (Sigma 700 Tensiometer, Sweden), and viscosity (CFOC-200 Viscometer, Cannon Company, USA) of various soft contact lens multipurpose solutions (MPS) were measured in triplicates at room temperature. Viscosity measurements were also taken at 34 °C ocular surface temperature. The solutions examined were Opti-Free Replenish (OFR), Trufresh (TF), Avizor (AV), Freshlook (FL), and Refresh (RF). Results: Several solutions were largely hypo-osmotic in the range of 108-231 mOsm/kg, the exception being Avizor, which had osmolality values that were closer to human tears (301 ± 0.58 mOsm/kg). The range of pH values of the solutions (6.33-8.24, mean (SD) = 7.53 ± 0.18) fell within the reported tolerable range for the ocular surface (6.20-9.00). Surface tension values ranged from 35.86 to 42.27 mNm with a mean of 38.49 ± 2.32 mNm. The average viscosity of most solutions at room temperature (25 °C) was 1.44 ± 0.49 cP with a range of 1.04-2.15 cP. Significantly lower values ranging from 0.79 to 1.58 cP were obtained at ocular surface temperature (34 °C), p = 0.0001). Conclusions: The physical properties of many of the solutions used as MPS in Ghana are markedly variable. Nevertheless, pH, surface tension, and viscosity fall within the acceptable limits of ocular physiological tolerance; except for osmolality, which majority were outside the reported tolerable range for the ocular surface. This information may partly explain the reason some patients exhibit strong preferences for certain care systems and should aid clinical decision-making when prescribing eye care systems to patients.
RESUMO
OBJECTIVE: To assess the differential association of myopia with major non-communicable ocular diseases in an African clinical cohort. METHODS: A five-year hospital-based retrospective study of myopia cases. Patients' folders, Optical Coherence Tomography scans, and fundus photographs were reviewed for the abstraction of relevant data. Only records that employed recognized standards and classification systems for diagnosing and staging the various ocular conditions were included. Demographic characteristics, non-cycloplegic objective refractive findings, and non-communicable eye diseases were retrieved from the records. Myopia-associated risk factors were then determined using logistic regression and correlation. RESULTS: Some 16018 patients (32027 eyes) met the inclusion criteria for at least one eye comprising 50.8% males (n = 8137) and 49.2% females (n = 7881). The mean age of the patients was 43.14 ± 17.88 years (range: 2-98 years). The mean spherical equivalent± Standard deviation for myopia was -2.30±3.23 DS (range: -0.50 to -25DS). Binary logistic regression analysis showed that myopic eyes had a higher odd of AC (OR, 0.53; 95% CI, 0.50-0.57), POAG (OR, 6.0; 95% CI, 5.26-6.82), DR (OR, 10.70; 95% CI, 3.91-29.27) and cataracts (OR, 20; 95% CI, 15.32-26.20) but not dry eye (OR, 0.74, 95% CI, 0.68-0.81), macular degeneration and pterygium (OR, 0.36; 95% CI, 0.32-0.40). CONCLUSION: Africans with myopia are more at risk of developing allergic conjunctivitis, cataracts, POAG, and DR but not for dry eye, macular degeneration, and pterygium.