Multifocal contact lenses are used to correct the age-related vision problem known as presbyopia. Despite these contact lenses being readily available to order online or buy from high street opticians, they are still underrepresented in terms of how much information there is on them and understanding how they work. This article will help you to understand multifocal contact lenses and getting them to work in more detail.
What factors contribute to success with multifocal contact lenses?
Both eye factors and lens factors as well as fitting and patient can influence the success of multifocal contact lenses. The following factors need to be considered in order to achieve success with multifocal contact lenses:
Dropout is a major factor with multifocal contact lenses and research shows that many people decide to give up on their multifocal lenses after just one year. This is often due to being dissatisfied with their vision but can also include issues relating to the aging eye such as tear film changes and discomfort.
Eye factors influencing the success of multifocal contact lenses include pupil size and lens clarity.
Pupil size gets smaller with age as well as when viewing near objects and when subjected to bright light. Therefore, if the centre near vision in a multifocal contact lens design is not optimised for all reading additions or distance vision, clarity can be lost as one's ages and their pupil size decreases. Luckily, most multifocal contact lens designs are adapted to these changes.
The clarity of the natural lens (crystalline lens) can also influence how well multifocal contact lenses work. Multifocal intraocular lenses are artificial lenses which are implanted into your eye. In removing the crystalline lens, these have advantages over regular multifocal contact lenses in that they provide clearer optics. It is important to check that clarity of a patient's crystalline lens before fitting them with multifocal contact lenses.
Lens factors influencing the effectiveness of multifocal contact lenses include centre near/centre distance designs and on eye affect.
Centre near/ centre distance designs
Different manufacturers have produced various multifocal contact lens designs to cater for centre near and centre distance vision. It is important to be aware of the differences with these variations of lens designs and to try more than one type of lens design in order to meet your visual needs.
On eye -affect
The optic of the eye should also be considered when fitting multifocal contact lenses. Everybody's eyes are different, therefore, the same multifocal lens with the exact same power and optical prescription fitted to eyes with the same pupil size will not necessarily produce the same results in terms of clarity of vision.
It is essential to get the right fitting with the right power selection, centration and lens material for one to experience success with their multifocal contact lenses.
Even the smallest changes in power can have a huge impact on one's experience with multifocal contact lenses. An extensive distance and reading power range, with small increments throughout is ideal.
Centration is ever so important when it comes to fitting multifocal contact lenses. If the lenses decentre then vision may be reduced.
Lens material is almost as important as lens design especially for those with presbyopia as the tear film stability reduces as one ages. It's best to choose a lens material which maintain tear film stability and minimises dry eye and discomfort.
The patient's lifestyle and expectations are important to consider when fitting multifocal contact lenses.
The patient and their lifestyle is an incredibly important factor when prescribing multifocal contact lenses. Daily contact lenses may be a great choice for presbyopes who don't wish to wear their multifocal contact lenses all the time. Those with low myopia (short-sightedness) may also find themselves in situations where they are capable of functioning well without correction. However, there will be certain situations where they will benefit from having multifocal contact lenses.
Communication between the patient and optician is essential when prescribing multifocal contact lenses and expectations need to be managed. Patients should be given positive but realistic expectations in terms of correcting their presbyopia.