Glaucoma is a painless eye disease that can lead to complete loss of vision if left untreated. It is possible to slow down its development by regularly monitoring its eye pressure. Eye drops, laser intervention, other drugs, new therapeutic avenue … Focus on treatments to overcome glaucoma.
In glaucoma, the eye pressure can be high. Indeed, it is regulated by aqueous humor, a liquid evacuated by the trabeculum. Due to the disease, this flow no longer occurs and the intraocular pressure increases. How to cure it ?
Eye drops to stabilize eye pressure
In most cases, local treatment with eye drops, or eye drops,is sufficient to effectively slow the progression of glaucoma by lowering eye pressure. It is necessary to deposit the drops in the eyes daily. This treatment is to take for life. There are four different families:
- Prostaglandins These drugs (bimatoprost, latanoprost and travoprost) facilitate the elimination of aqueous humor. They are usually prescribed as a first-line treatment and lower eye pressure by an average of 30% with just one drop in the evening. Two drawbacks, however: prostaglandins change the pigmentation of green eyes (which turn brown) and do grow eyelashes, make them fuller, an undesirable effect … which can be appreciable! On the other hand, the tolerance is very good: the product does not sting, does not cause allergy, just sometimes a redness, transient. To further reduce the risk of intolerance, latanoprost is available without preservative, in a single dose (Monoprost).
- Beta blockers As effective as prostaglandins, they decrease the synthesis of aqueous humor. One drop per day is sufficient with the prolonged-release forms, if not one morning and evening for the classic forms. Their prescription must obtain the endorsement of a cardiologistbecause they slow down the heart. Théa Geltim gel, which stays in contact with the conjunctiva longer, has 5 times less active ingredients and is just as effective, with fewer side effects. Second option, eye drops without preservative (Ophtim, Timabak, Carteol LP…). Contraindicated in asthma.
- Carbonic anhydrase inhibitors These eye drops (brinzolamide or dorzolamide) reduce the production of aqueous humor. They complete a first treatment and lower eye pressure by 15 to 20%, at the rate of one drop morning and evening. Forms without preservative (DualKopt or Cosidime) are associated with a beta blocker. Alternatively, a prostaglandin in the evening and a carbonic anhydrase inhibitor in the morning and evening. Of tingling and allergies are possible.
- Alpha-2-agonists This treatment (apraclonidine and brimonidine) decreases the production of aqueous humor. One drop morning and evening, associated with another eye drops, again because of its effectiveness limited to 15-20%. It is found in combination with a beta blocker or with a carbonic anhydrase inhibitor. Cons: “It contains a preservative and the may be poorly tolerated, accompanied by an risk of drowsiness », Warns Professor Giraud, head of the ophthalmology service of the Bégin army instruction hospital, Saint-Mandé.
Vitamin B3, a new avenue of treatment?
In May 2021, researchers from Karolinska Institutet and St. Erik Eye Hospital studied the effects of nicotinamide, a vitamin B3 compound, in animal and cellular models of glaucoma. These findings were published in Redox Biology. First results which could point to a future neuroprotective therapy. A clinical trial will begin in the fall of 2021.
Administration of nicotinamide
In previous studies, researchers had already identified that the NAD molecule declines in the retina in an age-dependent manner and makes retinal ganglion cells susceptible to neurodegeneration. Thus, the administration of nicotinamide would succeed in preventing the depletion of the molecule. Scientists have also found that elevation of NAD levels by administration of nicotinamide can improve visual function in patients with existing glaucoma.
“We have confirmed the nicotinamide neuroprotection in cell models and additional animals which recapitulate isolated features of glaucoma, but which are also common neurodegenerative features. We have also developed sensitive tools to study the metabolism of NAD, and the metabolism of other essential metabolites, in the visual system, ”explained study lead author James Tribble, a postdoctoral researcher in the Department of Clinical Neuroscience. the latter reports limited molecular side effects.
Glaucoma: laser can be offered straight away
Painless, and now minimally invasive, the trabeculoplasty is used more and more. Thanks to selective laser (SLT), this operation can now be offered as a first-line treatment, in particular to young people, whose optic nerve condition is worrying. For a time, it was offered as a last resort before surgery, if the treatment with eye drops was not effective enough. The difficulties of adhering to the treatment of glaucoma, and its possible hazards, are now scanned with the laser. Two sessions for each eye improve the permeability of the trabeculum for better better evacuation of aqueous humor. An effective intervention for 2-3 years, after which the treatment can be repeated once.
Medicines, in case of intolerance to eye drops
If we cannot stand any type of eye drops, we can resort to a medicine to swallow (carbonic anhydrase inhibitor, Diamox). This type of medicine can also be useful when eye pressure remains very high despite treatment with eye drops. It will allow the surface of the eye to rest and preserve the chances of success of a laser or surgical intervention.
Finally, if the eye drops or laser treatment are intolerable or ineffective over time, a surgery may be necessary. The surgeon may choose to perform a trabeculectomy or a sclerectomy. Each of these techniques aims to permanently lower eye pressure to stop the progression of the disease.