What does this mean?

In particularly complex cases — such as severe dry eye, chemical burns, congenital aniridia, or autoimmune diseases — oral mucosa can be used as an additional covering. This helps improve treatment outcomes and reduce the risk of complications, such as implant extrusion.

Why is this important?

• A more accessible alternative compared to other methods (e.g., osteo-odonto-keratoprosthesis).
• Less steep learning curve for surgeons.
• Provides better cosmetic results.
• Preserves the possibility of future retinal or glaucoma surgeries.

Conclusion

The combination of the Boston keratoprosthesis with oral mucosa represents a simpler, safer, and more aesthetically favorable option for patients who previously had very limited alternatives.

An example of how surgical innovations continue to transform ophthalmology and improve patients’ quality of life.

What determines our eye color?

Our eye color depends on the amount and distribution of a pigment called melanin in the iris — a fibromuscular tissue that forms the pupil diaphragm. There are two types of melanin: eumelanin (dark brown) and pheomelanin (reddish-brown). Depending on how much melanin is present in the iris epithelium and stroma, and the density of these tissues, the eye acquires a specific color.

What are the most common eye colors and why?

Globally, brown is the most common eye color, except in Europe, where a variety of colors such as hazel, green, blue, and gray appear. Initially, it was believed this was linked to genes that control skin pigmentation, but there’s no clear connection in most cases.

Some theories attributed this to genetic mixing with Neanderthals, but the limited gene flow doesn’t explain the high incidence of non-brown eyes in Europe. Other geneticists suggest it’s due to sexual selection: when one sex outnumbers the other, individuals compete for mates using traits like bright or unusual eye colors to attract attention.

Can we change our eye color?

Many people have a cosmetic desire to change their eye color, but achieving it is not simple. There are both reversible and irreversible techniques.

The simplest and most reversible method is cosmetic contact lenses, available in many colors. They provide excellent cosmetic results but must be used carefully to avoid complications such as conjunctivitis or serious corneal infections.

Among permanent solutions, there are surgical methods like keratopigmentation, or corneal tattooing. This involves creating a small circular pocket inside the cornea with a femtosecond laser and filling it with colored pigments, producing a convincing cosmetic effect.

Keratopigmentation is also used therapeutically in pathological eyes to correct iris defects.

Another technique involves iris depigmentation using a special laser that removes melanin and lightens the iris color. Artificial irises were also designed and implanted in front of the natural iris, but most cases had disastrous outcomes.

Are these techniques safe? What are the risks?

Laser depigmentation carries the highest risk. The laser releases pigment into the eye’s aqueous humor, which can clog the drainage meshwork and raise intraocular pressure, potentially causing glaucoma. If uncontrolled, this can lead to irreversible optic nerve damage and vision loss.

Keratopigmentation, being performed on the cornea, may cause minor changes in vision, affect night or peripheral vision, and complicate future intraocular surgeries. Long-term pigment tolerance and degradation are also important concerns. Though less aggressive, it still carries potential risks.

What is the ophthalmology community’s opinion?

Most ophthalmologists oppose elective eye color change surgery on healthy eyes due to the unacceptable risks. Laser depigmentation and artificial iris implants have been largely abandoned due to their serious complications.

In contrast, cosmetic keratopigmentation is being performed in a few international centers. However, the lack of long-term, peer-reviewed studies in prestigious ophthalmology journals — despite some positive conclusions — prevents widespread acceptance.

On the other hand, keratopigmentation for pathological cases is considered fully justified when it solves issues that impair a patient’s visual quality, such as partial or total loss of the iris.

As for cosmetic keratopigmentation, since it remains rare and controversial, caution is advised. Long-term results are needed to determine whether the procedure is truly safe and what complication rates exist, so that patients can be properly informed.

Medical article by Dr. Juan Álvarez de Toledo

It involves complete resection of a tumoral lesion located in the intraocular space. The advantage is that it completely removes the tumour and, in addition, it allows us to analyse its cell pattern in the laboratory, unlike other destructive techniques such as radiotherapy. These surgical procedures are highly specialised.

WHAT ARE ITS INDICATIONS?

Currently, due to the use of other treatment techniques like episcleral barchytherapy, the surgical procedure has been limited to the treatment of different types of very specific tumours located in the iris or the ciliary body.

Surgical techniques are also used for ab externo or ab interno removal of tumours of the back part of the eyeball.

HOW IS IT PERFORMED?

The ab externo surgical approach is performed on the white layer of the eye (the sclera) and the tumour is removed in one single piece with very specialist microsurgery techniques.

In the ab interno technique, the tumour is destroyed and aspirated inside the eyeball itself. It is a technique that basically uses certain melanomas of the posterior uvea and it is always combined with an episcleral brachytherapy to irradiate possible cellular remains at the base of the tumour.

RESULTS

The results are good in the sense that this technique eliminates the tumour completely and the eye still has a varying degree of vision.

The postoperative period is usually tedious due to the inflammation caused by the surgery and, in general, the patient will reach their final level of vision after a few months.

POSSIBLE RISKS

Depending on the location of the lesion and the technique used, an induced astigmatism, displacement of the pupil, cataracts, postoperative haemorrhaging, hypotonia or ocular hypertension or visual sequelae may occur. In these cases, you must undergo a very close clinical follow-up to identify and treat any complications.

PROFESSIONALS WHO PERFORM THIS TREATMENT

Dr. Javier Elizalde

A macular hole is the name for the formation of a break in the centre of the retina, the area which call the macula. It usually occurs in people over the age of 50 and it is more common among women. It can be bilateral in 15% of individuals.

Its diagnosis is clinical, i.e., viewing the back of the eye after dilating the pupils and using magnifying lenses. However, in all cases, we will perform a scan of the macula (OCT or optical coherence tomography) to measure the size and thickness of the macular hole, upon which will depend the prognosis and potential treatment.

SYMPTOMS

The clinical signs of a macular hole can vary: from patients who are completely asymptomatic at the start to a severe loss of vision and the appearance of a blind spot in the centre of the eye (scotoma).

Metamorphopsia (perception of distorted images and straight lines with undulations) is also very common as is macropsia and/or micropsia (seeing objects as larger or smaller than they are in reality).

A very characteristic symptom of this condition is seeing broken lines, known as the “Watzke-Allen sign”.

CAUSES AND RISK FACTORS

It is believed that its cause lies in the traction that the vitreous humour (transparent gelatinous liquid filling the eyeball) exercises over the macula when it contracts, because of a physiological ageing process. Under normal conditions, when we get older, the vitreous detaches, i.e., the intraocular gel recedes and moves away from the macula without causing any damage thereto or having any consequences on the eyesight. However, in some people, the vitreous cortex has strong adherence to the macula and a sharp focal contraction thereof leads to a break in the macular tissue and the formation of a macular hole.

We can also experience a macular hole after a blunt eye trauma, in the context of a high degree of myopia or a chronic macular oedema complication.

TYPES

Macular holes can be classified in different ways:

— According to their cause: Idiopathic or senile (associated with ageing), myopic (those that occur to patients with a high degree of myopia) and traumatic (the consequence of previous trauma).

— According to the thickness of the damaged retina: Full-thickness (when the hole affects the full thickness of the retina) and lamellar (when they partially affect the thickness of the retina) associated, in general, with the epiretinal membrane.

— According to the OCT findings: A complex classification that we do not mention herein.

PREVENTION

There is no way of preventing a macular hole from forming. What is important, however, is diagnosing it at a very early stage when surgery is very effective. Therefore, regular eye check-ups, above all in patients who have had the same condition in the contralateral eye, are advised.

TREATMENT

Macular hole treatment is eminently surgical.

The surgery is called a vitrectomy . It is an outpatients procedure and performed under local anaesthesia. It’s a microincision technique, i.e., it uses microscopic incisions that do not require stitches. It involves removing all the structures that cause traction on the macula, be it the vitreous humour, the epiretinal membrane or the internal limiting membrane of the retina (the outermost layer of the retina).

At the end of surgery, a gas bubble is injected into the vitreous cavity (intraocular tamponade), which helps the macular hole to close. For the days following surgery, patients will have to stay in quite a strict position (generally seated or with the mouth facing downwards), depending on the type of duration of the gas.

The surgical outcomes are more promising the less the disease has evolved and the smaller the size of the hole. In early cases, there is a high percentage of anatomical closure and a considerable improvement in visual acuity compared to more advanced cases or macular holes in myopic eyes.

PROFESSIONALS WHO TREAT THIS PATHOLOGY

• Dr. Santiago Abengoechea
• Dr. Mª José Capella Elizalde
• Dr. Javier Elizalde
• Dr. Jeroni Nadal
• Dr. Sònia Viver

The word brachytherapy comes from the Greek (“brachys”) which means “near”, and it is a type of local radiotherapy which allows the tumour to be treated with radiation from a source that is in contact with or even inside the affected organ. The most commonly used radioactive isotope is Iodine-125. In ophthalmology, the radioactive source is placed above the sclera (episcleral), which is the white part of the eye.

WHAT ARE ITS INDICATIONS?

The first indication of episcleral brachytherapy is uveal melanoma, although it can also be used to treat intraocular tumours (retinoblastoma, metastasis and vascular tumours of the retina and choroid).

• Choroidal hemangioma
• Uveal melanoma
• Vascular tumours of the retina

HOW IS IT PERFORMED?

It is a surgical procedure that involves attaching a gold plaque charged with radioactive isotopes to the eyeball in the location of the tumour. The size of the plaque and dose is determined on an individual basis, depending on the type of tumour and its size.

A well-coordinated team including an expert ophthalmologist and radiation oncologist who decides how long the plaque should be in situ is essential. After this period (usually 3 to 5 days) the plate is removed.

RESULTS

In a high percentage of cases, healing of the tumour is acheived, but not immediately. The patient should have clinical checks and regular ultrasound scans to check that the tumour has not returned. The final resolution of the tumour usually occurs after a few months.

POSSIBLE RISKS

The radiation emitted by the episcleral brachytherapy does not affect other organs or people in the vicinity, since it is very localised radiotherapy. In general, it’s a treatment with very few undesired effects.

When the tumour is located on the inner part of the eye there is a risk of developing a radiogenic cataract and in cases where a lesion close to the central retina or optic nerve is being treated with radiation, radiation retinopathy or radiation neuropathy may appear along with reduced vision.

PROFESSIONALS WHO PERFORM THIS TREATMENT

Dr. Javier Elizalde

The retina is a sensitive tissue of the eye containing a multitude of blood vessels. These vessels may grow and proliferate anomalously, be it from birth or acquired, leading to different vascular tumours of the retina.

TYPES

There are four types:

1. Capillary hemangioblastoma (which is occasionally associated with Von Hippel-Lindau syndrome).
2. Cavernous hemangioma.
3. Vasoproliferative proliferal tumours.
4. Racemose hemangioma (congenital arteriovenous communications of the retina).

SYMPTOMS

The symptoms depend on the type of tumour and its location. Hemangioblastoma of the retina and vasoproliferative tumours can exudate (lose liquid), leading to exudative retinal detachment or it may generate proliferations that exert pressure on the retina.

In these cases, the patient show signs of gradually worsening vision. Cavernous and racemose hemangioma are congenital and if they are located near the centre of the retina, they can lead to underdeveloped eyesight (amblyopia).

TREATMENT

There are multiple treatment alternatives depending on the type of tumour, its location and the associated complications. The most used treatments are intravitreal drug injections that can reduce vascular permeability, laser, cryotherpay and vitreous surgery to treat tractional complications or retinal detachment, episcleral brachytherapy and external radiotherapy. In many cases, combined treatments are required. It is a complex pathology that should be treated in a centre of reference.

• Episcleral brachytherapy
• External radiotherapy
• Laser photocoagulation

PROFESSIONALS WHO TREAT THIS PATHOLOGY

Dr. Javier Elizalde

This certification guarantees that Barraquer works on clinical and experimental projects with the highest quality standards and following the European and international directives for clinical research. Currently, the Centre’s research department promotes more than 20 clinical trials, with the participation of around 80 patients, focused on pathologies such as AMD, dry eye, glaucoma or diabetic macular oedema.

It’s a surgical procedure for the treatment of glaucoma that involves inserting a tube to connect the intraocular tube with a device (that may or may not have a valve) located below the conjunctiva to drain the aqueous humour from the eye.

WHEN IS THIS TREATMENT INDICATED?

Generally, it is used for glaucoma where other types of filtration surgery have failed, for types of glaucoma where the result is better than other techniques like for neovascular glaucoma, or when the state of the conjunctiva would prevent the use of surgical techniques.

HOW IS IT PERFORMED?

It is perfomed under local anaesthetic and sedation, so that the patient is completely calm. The majority of the device is placed on the outside of the eye, below the conjunctiva.

A small tube is place in the anterior chamber of the eye. The liquid drains through the tube to the posterior part of the implant where it builds up and is reabsorbed.

RESULTS

The results of drainage devices may vary depending on the type of glaucoma, the age of the patient, the state of the conjunctiva and the number of previous surgeries. They normally control the intraocular pressure in the majority of cases, although over time topical treatment should be added to control it.

POSSIBLE RISKS

There is the possibility that the pressure is too low. This is known as “hypotony”. The implant may also interfere with the external muscles that move the eye causing double vision.

If there is excessive scarring around the device, it may block the fluid from being reasborbed, which, once again, leads to an increase in the pressure. To treat this, hypotensive eyedrops or new procedures may be required.

Other complications may include corneal lesions, which may be due to the mechanical contact between the tube on the inside of the eye and the inner part of the cornea.

PROFESSIONALS WHO PERFORM THIS TREATMENT

Dr. Maria Isabel Canut
Dr. Francisco Ruiz Tolosa
Dr. Federico Trejos

Within the scope of glaucoma, we should be aware that the thickness of the cornea is related to the measurement of intraocular pressure, in that corneas that are thicker or less thick than average may give flawed readings on pressure measurement devices which should be corrected.

Concerning refractive surgery, a pachymetry is one of the most important examinations for determining whether a person should undergo laser treatment for their myopia, hypermetropia or astigmatism, since the surgery modifies the shape of the cornea, extracting a certain amount of tissue which will directly affect the thickness of the cornea. Therefore, the cornea should be thick enough to correct a given number of dioptres.

It is also a diagnostic tool for some pathologies that cause a thinning of the cornea as per the case with keratoconus or even those that cause thickness as per the case with corneal oedema.