Publicação
Defocus curves with different multifocal contact lenses in presbyopes
| Resumo: | Presbyopia is the most common age related dysfunction in humans, affecting about 50% of the population at the 45 years of age. One of the current techniques to correct presbyopia with multifocal soft contact lenses (MFSCL) is based on simultaneous vision. Considering that different MFSCLs have different optical designs, they could interfere differently in the vision of patients. Despite the progress that has been made in recent years, subjects rarely report perfect vision at all distances with multifocal lenses and CL correction of presbyopia has long been a major challenge, due to the difficulty of producing complex lens designs capable of providing sharp vision for every visual task at all distances. The evaluation of the defocus curves can provide a useful method to compare different presbyopia correcting strategies, overcoming many of the issues of only measuring distance and near VA. However, the duration of the through-focus exam to obtain the defocus curves is one of the main problems of the method. Stating this, one of the main goals of the current study was to mount an automated Badal optometer to induce different levels of defocus, and once it was validated and proved to be an easy and rapid way of measuring defocus curves (reducing about 30% of the examination time), to use it and test the through-focus performance of presbyopic patients wearing multifocal contact lenses. The performance of a new combination of lenses with different multifocal designs in both eyes (Mix&Match) was evaluated and it was compared to a typical and normal fitting (Purevision 2 Multifocal) in presbyopic subjects. After a week of each lenses wear, both fitting approaches proved to provide the achievement of very satisfactory results when comparing with the patient’s best correction in spectacles. Both lenses provide acceptable visual acuity for all distances, and it was shown by the defocus curves measured with each lenses as by the visual acuity measured in different contrast conditions for distance and near vision. After a week of lens wear, and despite some asymmetry between both eyes in the Mix&Match method, both fitting approaches proved to be a suitable option to consider for presbyopia correction. |
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| Autores principais: | Neves, Helena |
| Ano: | 2013 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Presbyopia is the most common age related dysfunction in humans, affecting about 50% of the population at the 45 years of age. One of the current techniques to correct presbyopia with multifocal soft contact lenses (MFSCL) is based on simultaneous vision. Considering that different MFSCLs have different optical designs, they could interfere differently in the vision of patients. Despite the progress that has been made in recent years, subjects rarely report perfect vision at all distances with multifocal lenses and CL correction of presbyopia has long been a major challenge, due to the difficulty of producing complex lens designs capable of providing sharp vision for every visual task at all distances. The evaluation of the defocus curves can provide a useful method to compare different presbyopia correcting strategies, overcoming many of the issues of only measuring distance and near VA. However, the duration of the through-focus exam to obtain the defocus curves is one of the main problems of the method. Stating this, one of the main goals of the current study was to mount an automated Badal optometer to induce different levels of defocus, and once it was validated and proved to be an easy and rapid way of measuring defocus curves (reducing about 30% of the examination time), to use it and test the through-focus performance of presbyopic patients wearing multifocal contact lenses. The performance of a new combination of lenses with different multifocal designs in both eyes (Mix&Match) was evaluated and it was compared to a typical and normal fitting (Purevision 2 Multifocal) in presbyopic subjects. After a week of each lenses wear, both fitting approaches proved to provide the achievement of very satisfactory results when comparing with the patient’s best correction in spectacles. Both lenses provide acceptable visual acuity for all distances, and it was shown by the defocus curves measured with each lenses as by the visual acuity measured in different contrast conditions for distance and near vision. After a week of lens wear, and despite some asymmetry between both eyes in the Mix&Match method, both fitting approaches proved to be a suitable option to consider for presbyopia correction. |
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