Abstract
Purpose
Lens shape, variations in function-related parameters, and contamination of soft contact lenses past their expiry date were investigated.
Methods
Two types of soft contact lenses made of different materials were examined. The lenses that were left an expiry date over one year, almost expired, and past their expiry date according to the criteria on usage period specified by manufacturer were investigated. Their total diameter, radius of curvature, central thickness, refractive power, water content, oxygen permeability, visible light and UV transmittance were measured, and the presence of bacteria was further measured according to the criteria about stability and safety of contact lenses proposed by the Ministry of Food and Drug Safety.
Results
There was a statistically significant change in almost expiring narafilcon A lens as well as the narafilcon A lens past its expiry date. That is, total diameter and refractive power of the lenses increased, and central thickness and oxygen permeability of the lenses statistically decreased. In nelfilcon A lens past the expiry date, the decrease in total diameter, radius of curvature, visible light transmittance, and the increase in water content were statistically significant. However, bacterial contamination was not found in all lenses.
Conclusions
In this study, it was revealed that the parameters of soft contact lenses that were nearly expired or past the expiry date changed, and their degree of change varied depending on the lens material. Therefore, it is suggested that the usage period of the soft contact lens should be appropriately determined depending on the material.
Lens shape, variations in function-related parameters, and contamination of soft contact lenses past their expiry date were investigated.
Methods
Two types of soft contact lenses made of different materials were examined. The lenses that were left an expiry date over one year, almost expired, and past their expiry date according to the criteria on usage period specified by manufacturer were investigated. Their total diameter, radius of curvature, central thickness, refractive power, water content, oxygen permeability, visible light and UV transmittance were measured, and the presence of bacteria was further measured according to the criteria about stability and safety of contact lenses proposed by the Ministry of Food and Drug Safety.
Results
There was a statistically significant change in almost expiring narafilcon A lens as well as the narafilcon A lens past its expiry date. That is, total diameter and refractive power of the lenses increased, and central thickness and oxygen permeability of the lenses statistically decreased. In nelfilcon A lens past the expiry date, the decrease in total diameter, radius of curvature, visible light transmittance, and the increase in water content were statistically significant. However, bacterial contamination was not found in all lenses.
Conclusions
In this study, it was revealed that the parameters of soft contact lenses that were nearly expired or past the expiry date changed, and their degree of change varied depending on the lens material. Therefore, it is suggested that the usage period of the soft contact lens should be appropriately determined depending on the material.
| Translated title of the contribution | The Stability and Safety Evaluations of Soft Contact Lenses past their Expiry Date |
|---|---|
| Original language | Korean |
| Pages (from-to) | 33-40 |
| Number of pages | 8 |
| Journal | 한국안광학회지 |
| Volume | 22 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 2017 |