GENERAL OPTHALMOLOGY AND INTRAOCULAR LENS UNIT

 

 

 
 

The FOM's General Ophthalmology and Intraocular Lens Unit undertakes comprehesive eye exams, diagnosis and treatment of all pathologies as well as surgical planning.

Diagnostic tests and treatments

1. General ophthalmological exploration:

In the course of general ophthalmological exploration (known as “the check-up”) patients usually undergo the following tests:

-Visual acuity with or without correction (glasses, contact lenses) measuring visual capabilities with the aid of a series of scales for both near and far vision.  
- Eye pressure test,  sistematically aimed at people over 40 -or even earlier if family history suggests so. Ophthalmologists have several devices to measure it. It's important to discard high pressure within the eye, for it constitutes the main risk factor to develop a disease called glaucoma, which may irreversibly harm the optic nerve.  

Through the slit lamp (providing a chin-rest for the patient to stay motionless as the specialist explores their eyes), observation of ocular inner (cornea, iris, crystalline lens) and outer (optic nerve, macula, peripheral retina) structures.

2. Cataract surgery.

What are cataracts about?

To understand what cataracts are it's necessary to know , first of all, what a crystalline lens is. The shape of a lentil and -in normal conditions- utterly see-through. It's located behind the iris, which is the part that gives color-related features (brown, green, blue,...).

For different reasons, the crystalline lens ceases to be transparent. In practise, it's like we tried to see through a steamed glass (the more steamed, the less we can see), hence the term “non-transparent crystalline” to refer to cataracts themselves.

Why do they appear?

Age is the most common cause. Traumatisms, intake of specific drugs or other diseases (above all metabolic alterations like diabetes) count as possible triggers  too. We talk about about congenital cataracts when lack of transparency can be recognized at birth.

How are they treated?

Surgery is, for the moment, the only possible treatment. There is not a drug capable of restoring crystalline lens's transparency.

What does cataract surgery consist of?

We use surgery to remove the cataract (e.g clouded non-transparent lens) and replace it for an artificial lens to allow optimal vision.
There exist several surgical techniques; the most widespread one being -in our context- phacoemulsification. As such, it involves dissolution and aspiration of the cataract by means of an ultrasound terminal through a small incision. The aim is to preserve the largest part of the crystalline capsule (the size of a lentil peel) to house the artificial lens in it.  The latter can also be laid behind -or in front of- the iris. Incision might or might not require suture.
Nonetheless ultrasounds are, in some cases, ineffective to remove cataract, whereupon more pressure is necessary for exctraction. This technique is equally   effective though it requires a longer recovery period.

What are the results?

In the last few years there have been -and there continue to be- significant advances in the field of techniques to obtain the best results and reduce to a minimum any possible complication.
At the present time overall results are excellent, with a noteworthy shortening of the perioperative period and an infrequent incidence of serious complications; however, this is a tricky piece of surgery that is not risk-free and needs to be carried out by an eye surgeon.
In addition, it must be considered that every case is different and not all the eyes -not even a single person's eyes-  have the same response to the same surgical manoeuvres

What complications might appear?

As in any intervention, cataract surgery may bring some complications. The large majority of them are mild and can be solved with medical treatment. Still, on certain occasions patient may need a new operation. Albeit uncommon, risk of vision loss also exists.
 
How do they evolve if untreated?

As they evolve, patient loses eyesight progressively and, in most cases, slowly. Should they reach an advanced stage, they might -unfrequently, but possibly- increase intraocular tension and cause inflammation. Added to this is the fact that advanced cataracts are more difficult to remove and result in a higher risk of complications.

When is it necessary to undergo surgery?

The right time to have a cataract removed is when benefits overcome intervention-related costs. This will depend on every patient's visual needs. Thus, it's inadvisable to operate unless everyday activities are affected or advanced stage entails evident risk for the eye.  

What are we going to achieve with surgery?

We will be able to restore eyesight as long as we can rule out -and not be impeded by- any other ocular alterations. In the large majority of cases prescription glasses will be needed.

3. Intraocular lenses

Crystalline lens is the natural lens that makes vision possible. With the passage of time, it will lose transparency and give rise to a cataract (crystalline lens opacity). Cataracts have a surgical treatment, which comprises crystalline lens extraction and the unsuing replacement for an artificial one called “intraocular lens”. Long time ago, patients operated on for cataracts were not given a chance to have an intraocular lens implanted (lensless aphakic eye) and they had to wear thick glasses to ensure eyesight. In 1950, Dr. Sir Harold Ridley succeeded in implanting the first intraocular lens; since then, intraocular lenses have eperienced a rapid increase in sophistication. The first few models were rigid and needed wider incisions for implantation. Conversely, the more modern lenses can be folded and introduced through narrower incisions. Intraocular lenses are not only used for cataract surgery but also to treat high refractive errors like myopia, hypermetropia and stigmatism.

Intraocular lenses for aphakia correction

Aphakia is the absence of the lens of the eye; on many occasions, it occurs when the crystalline lens has been surgically extracted, which may trigger serious long-sightedness. This situation can be corrected thanks to an intraocular lens, whose implantation will depend on the presence of the outer capsule (behind the iris if so, in anterior chamber if not). Thus, iridian subjection and angular support are the most common interior chamber lenses to treat aphakia.

Intraocular lenses to correct high myopia and/or hypermetropia

These lenses are specially meant to correct ametropia, which can be high or low in patients whose pachymetry test reveals low corneal thickness. Depending on the model, they are placed in the anterior chamber (angle-supported or iris-fixated lenses) or in the posterior chamber of the eyeball (between the iris and the anterior side of the crystalline lens). When the patient is young, the lens is implanted as their crystalline lens is preserved in order to ensure accommodation.

Intraocular multifocal lenses, correction of presbyopia

They are special intraocular lenses capable of focusing, they afford an optimal near and far vision. The ideal multifocal lens -allowing patients to see from all distances: near, intermediate, far- doesn't exist. As a matter of fact, Intraocular Multifocal lenses work because they divide light into two focuses: near and far. For both distances, vision  will be good; but not for “every single distance” since there is not a focus for each one of them.   


Accommodative Intraocular Lenses

Lenses that move forward and backward inside the eye, whose motion makes it possible to focus on far and near objects. Other tools for long-sightedness treatment are monovision and conductive keratoplasty.

4. Monovision

The dominant 0-diopter eye will assume far vision functions and so give up the near work to the non-dominant short-sighted eye. This technique encompasses use of laser, fakik lens or intraocular lens. Yet, not everyone might be a good candidate and a preoperative study should determine feasibility.

5. Conductive keratoplasty

In this procedure the centre of the cornea is curved by applying radiofrequency energy in a ring pattern. Local anesthesia is used. The process is similar to monovision; in reality, it's commonly known as “blended vision”, which results in good near vision. The patient can see well close-up and set aside prescription glasses in daily activities except small print reading. It hardly affects far vision. This procedure is suitable at the early stages of long-sightedness, when patients have never used glasses or no longer want to wear near vision spectacles. However, this procedure doesn't have lifelong effects and may require some further adjustments (consisting of a few additional sutures around the previous ones).

6. Capsulotomy YAG

In the course of surgical intervention, cataract removal is followed by crystalline lens extraction, whose posterior capsule will be kept. Such a capsule will hold the intraocular lens that has just been introduced.
At times this transparent layer becomes opaque and may cause a patient (who has been able to see perfectly since cataract intervention) to lose vision. The “cleaning” of this opacity demands the action of laser rays on this “outer bag”(capsulotomy), which open a new path for them to sea through the orifice. This technique is used to treat glaucoma; more specifically, to increase aqueous humor flow, facilitate circulation (trabeculoplasties,  iridotomies) as well as enlarge pupils or construct new ones (pupilloplasty).
Unlike argon laser, this a a photodisruptive laser; in other words, light works as a scalpel and is able to cut through body tissues. To use it, pupil dilation won't always be necessary, nor will the utilization of a magnifying contact lens.