Laser iridotomy
A laser iridotomy ( Laser Peripheral Iridotomy , LPI) is an operation in ophthalmology that uses a laser to create tiny holes in the iris . These serve as additional flow opening for the aqueous humor circulation between front and rear chamber of the eye . It is used for eye diseases such as narrow-angle glaucoma . The principle is similar to iridectomy , but without resection and is therefore non-invasive.
indication
The intraocular pressure is determined by the generation and outflow of aqueous humor. If the drainage is disturbed, the pressure increases. Persistent or excessively high intraocular pressure can damage the optic nerve . A glaucoma untreated, it leads to total blindness of the eye . Laser iridotomy creates a direct connection between the anterior and posterior chambers of the eye so that aqueous humor can easily drain from the posterior to the anterior chamber. This enables the eye to better regulate internal pressure.
The laser iridotomy is a precautionary measure for patients with attack-like increased intraocular pressure, caused for example by a flat anterior chamber with a pronounced overview . Other applications are extremely flat eyes or gluing the iris. It is also used as therapy for glaucoma that has already been diagnosed.
In many cases, this method has replaced iridectomy because it is much gentler. The latter is still used in exceptional cases, for example with a severely clouded cornea . The iridotomy requires a clear cornea.
surgery
This is usually carried out on an outpatient basis and under local anesthesia. It is painless with few risks and side effects. There is no provision for opening the eyeball.
Before the operation, eye drops numb the eye and narrow the pupil . Then a contact glass is placed on the cornea to protect it. The laser fires a tiny hole through this lens on the upper side of the iris (11 to 1 o'clock position). The Nd: YAG laser is the first choice for surgery , followed by a combination of argon and Nd: YAG lasers.
The operation is over after a few minutes. With the preparations, the procedure takes about half an hour. The patient will not feel the holes and they will not cause any discomfort.
Complications
Immediately after the operation, pigments can leak from the iris and prevent the aqueous humor from flowing out, causing the intraocular pressure to temporarily rise. Likewise, the cornea may be irritated or your vision blurred, caused by a gel used to attach the contact lens. The eye drops to constrict the pupil can also lead to blurred vision or headaches. Inflammation can also occur. However, these symptoms can be treated quickly and often go away on their own within a short time. Occasionally there is bleeding in the anterior chamber of the eye, but this usually does not require medical treatment.
In extremely rare cases, damage to the lens or cornea occurs. These can be treated with ointments and eye drops and usually do not cause any deterioration in vision.
A possible, longer-lasting side effect is the creation of glare or halos, caused by scattered light that reaches the retina through the additional opening . If the rare effect occurs, the brain adapts and fades out the artifacts on its own after a while. To prevent this phenomenon, surgeons can place the hole on the side of the iris (3 or 9 o'clock position). However, since the risk is low, the hole is often made in a traditional location; especially if it is covered by the eyelid .
Since the very fine holes can close again, the operation may have to be repeated several times. Patients of African or Asian descent tend to have thicker irises so they may need more laser energy or two different lasers. In about 25% of the cases, the operation is unsuccessful.
Individual evidence
- ↑ a b c d Laser iridotomy. In: oculus guide. Retrieved August 23, 2019 .
- ↑ Basal iridectomy. In: oculus guide. Retrieved August 23, 2019 .
- ↑ Anselm Kampik, Franz Grehn (ed.): Ophthalmic therapy . 2002, ISBN 978-3-13-128411-2 .
- ↑ Shalini Mohan, Vinay Gupta, Ramanjit Sihota: Laser Peripheral Iridotomy . In: DOS Times . Vol. 10, No. 7 , January 2005, p. 250–253 ( PDF [accessed September 3, 2019]).
- ↑ a b c Yvonne Ou: Side Effects of Laser Iridotomy. In: BrightFocus Foundation. October 15, 2018, accessed August 23, 2019 .
- ↑ Laser Iridotomy: 10 Commonly Asked Questions. In: Glaucoma Research Foundation. July 15, 2019, accessed August 23, 2019 .
