Laser technology brought significant transformation in the medical industry especially in the branch of ophthalmology. Laser beam is used to cut, shrink, remove, photocoagulate and extend the ocular tissues. And as new laser technology and its application continue to develop, we’ll discuss the YAG laser and its role in treating ophthalmic anomalies.
A brief intro
YAG laser is a solid-state beam which uses neodymium-doped yttrium-aluminium-garnet crystal as the primary lasing medium. It’s optically directed through a lamp or diode, emitting infrared light at approximately 1064-nanometres that can be used either in continuous or pulsed mode. Of the both, pulsed YAG lasers are Q0switched which gives them the high-intensity pulses that can be doubled in frequency to emit light at around 532-nanometres.
In the branch of ophthalmology, there’re many different applications for the YAG laser used mostly for treating posterior capsular opacification post cataract surgery which creates a marginal iridotomy among the patients with an angle-closure or thin slant glaucoma. YAG laser is also used to dissect the anterior capsule for capsular phimosis and capsular block surgery alongside cutting the vitreous chains in the anterior cavity.
In a more severe or malignant forms of glaucoma, the lasers are also used for cyclophotoablation of the ciliary body. These have proven beneficial for draining the pre-macular subhyaloid haemorrhages among the patients of Valsalva retinopathy. Doubling frequency of the YAG lasers would make it apt for performing pan retinal photocoagulation whereas other common applications include treatment of persistent vitreous floaters and corneal abrasion.
Detailed description of the procedures
Secondary cataract in typical medical terminology is referred to as “posterior capsular opacity” for which YAG laser treatment centrally opens the subsequent capsule. Patients are then pre-treated with Alphagan-P or iopidine for preventing IOP spike before given topical anaesthesia. Laser treatment is then executed using a slit-lamp delivery system using just the appropriate contact lenses which stabilises the eye as well as focus of the laser beam.
YAG laser can be modified accordingly to cut the capsule in many other conditions. When viscoelastic is retained in the capsular bag behind the IOL, it results in the capsular block syndrome causing a myopic shift, evident on the slit-lamp examination as apparent space between posterior capsule and the IOL surface.
The laser beam punctures the frontal capsule to the exterior IOL which drains the trapped material. Then again, subsequent capsulotomy can be created to achieve likewise results. When radial anterior capsulotomy is created with a YAG laser, it effectively treats the condition.
Long gone are the days of surgical iridectomising, now replaced with lasers for the treatment of the angle-closure glaucoma. The non-invasive laser procedure is achieved prophylactically in the eyes through narrow angles. Energy of the laser beam requires a range between 4-and-10mJ depending on pigmentation and thickness of the iris. Though the laser may result in bleeding, it gives for a more easy and efficient iridotomy than the Argon Laser.
Indeed, there’re many different uses and benefits of YAG laser in ophthalmology which sets it apart from many other laser-based eye surgeries.