When we operate our patients of myopia, ; farsightedness; astigmatism or presbyopia (eyestrain) to eliminate the use of prescription glasses, we use Multifocal intraocular lenses. We are currently implanting Trifocal lenses, that is, lenses with a focus for far vision, another for intermediate vision and another for near vision.
This optical system means that patient does not have to depend on wearing glasses for most of the daily visual activities, and basically, depending on the size of the pupil that the patient has throughout the day, patient will use one or the other focus.
Esto ha supuesto gran cantidad de pacientes contentos en las consultas de oftalmología, pudiendo ofrecer una serie de prestaciones que hace años eran impensables.
However, these lenses are still a complex optical system, so an optimal candidate is required.
When the patient attends the consultation for the preoperative examination, a complete rigorous study is performed with ocular parameters and with very sophisticated technology such as OCT ( optical Coherence Tomography)and optical biometry.
These tests allow us to know that there are no associated retinal problems and that the eye meets the ideal characteristics for the implantation of these lenses.
In this examination, the Axial length, the thickness of the lens, the anterior and posterior surface of the cornea, the distance in the anterior chamber of the patient, the total corneal astigmatism, the pupillary diameter in low light conditions (mesopic) are measured. The quality of the tear film is also valued, which greatly affects the visual quality after surgery, and we also observe the decentration of the visual axis with respect to the pupillary center (Kappa angle).
Todo ello , nos lleva a concluir que un paciente es candidato ideal o no a las actuales lentes difractivas multifocales.
Clásicamente, tenemos problemas en pacientes con pupilas muy grandes y con ángulos Kappa muy altos, disminuyendo la calidad visual, a pesar de ver en todas las distancias.
A new refractive lens is now available. With this lens, implants can be performed in all these patients who are doubtful to implant the classic lenses. This new concept is known as Continuous Transitional Focus (CTF), from OPHTEC. It is the Precizon Presbyopic lens, which has different segments in its optics, and with each of them, there is near and far vision, presenting a very smooth transition zone between both.
Advantages of these lenses are:
1.-The halos around the headlights of the cars are not seen, therefore there is no difficulty for night driving.
2.-It is a more independent pupil lens, which can be implanted in people with large pupils and the visual quality does not diminish.
3. It is suitable for people who have decentration of the pupillary axis (Kappa angle greater than 0.5), due to a diameter of the central zone greater (1.4 mm) than other lenses have. It also has an area perpendicular to this of 2.6 mm, which is made to coincide with the visual axis, simply by rotating the lens inside the eye once it has been implanted.
4.-Patients with dry eye have a good tolerance to this lens, and visual quality is less affected.
5.-If the lens decenters into the eye, it would not be a problem, because it is a lens with near and far vision in any of its segments.
We must understand that all intraocular lenses are prostheses, and it is not comparable to the vision we had when we were twenty years old. We are currently advancing by leaps and bounds in technology and this has an impact on better benefits for our patients improving their lives having more activity enjoying a senior life one hundred percent.
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