Treatment of Glaucoma
The goal of glaucoma treatment is to decrease the pressure in the eyes. This is achieved using special eye-drops or medications. Surgery is recommended if medications don’t yield the desired result, or with an aim to prevent further vision loss or blindness. Depending on your particular situation, surgical options include:
- YAG Laser: A YAG targets specific cells in the trabecular meshwork by using a powerful beam of light directed into your eye. This treatment eases the outflow of fluid from the eye, thereby reducing the pressure inside the eye.
- Peripheral Iridotomy: This procedure is used for a relatively less common type of glaucoma called closed angle glaucoma that causes a sudden build-up of pressure in the eyes, which can lead to an irreversible loss of side and central vision. During iridotomy, the laser creates a small hole in the outer region of the iris (coloured part of the eye). This allows free circulation of fluid in the eye, thereby lowering the eye pressure.
- SLT (Selective Laser Trabeculoplasty): SLT is employed in the most common type of glaucoma called open-angle glaucoma that develops slowly over time. During SLT, the frequency of the laser beam is varied to target specific cells of the trabecular meshwork. This procedure opens up the clogged areas in the mesh work, making it easier for the fluid to flow out of the eye.
- Trabeculectomy with or without antibiotics with releasable sutures: Trabeculectomy is a commonly employed surgical procedure that relieves pressure in the eye caused due to glaucoma. It involves creation of a new drainage channel that allows the fluid to drain out of the eye leading to the formation of a bleb covered by a white outer covering (conjunctiva) of the eye. The drainage site may scar over time leading to its closure. This scar formation can be prevented with the help of antimetabolites, which act by inhibiting the multiplication of cells forming the scar tissue.
- Express Shunt: This is a simplified version of trabeculectomy. This procedure uses an extremely small tube to divert the fluid to outside of the eye. As only controlled and precise amounts of fluid are let out, the internal pressure of the eye stands maintained at a healthy level.
Glaucoma surgery involves either laser treatment or conventional surgery in which a cut is made in the eye to reduce intraocular pressure (IOP) for preventing further vision loss or blindness.
Glaucoma is an eye disease that results in progressive vision loss due to the increased intraocular pressure and subsequent optic nerve damage. Optic nerve is a bundle of nerve fibres that carries visual images or signals from the eyes to the brain. In general, a clear fluid called aqueous humour circulates through the eye and then drains out through a mesh-like channel (trabecular meshwork). Whereas, in glaucoma this channel becomes blocked and fluid does not drain properly thus increasing pressure inside the eye (intraocular pressure). This increased intraocular pressure causes damage to the ocular nerves and blood vessels resulting in loss of vision.
Types of glaucomaThe different types of glaucoma include:
Open Angle Glaucoma: This is the most common form of glaucoma, also called primary or chronic glaucoma. This type of glaucoma occurs when the eye's drainage system becomes clogged and gradually increases the pressure inside the eye. The angle between the iris and cornea is wide and open.
Closed Angle Glaucoma: This type of glaucoma is less common and can cause a sudden build-up of pressure in the eye. The angle between the iris and the cornea is narrow or closed.
Normal tension (pressure) glaucoma or low tension glaucoma: In this type of glaucoma the optic nerve is damaged despite normal intraocular pressure.
Congenital Glaucoma: This type of glaucoma is seen in babies and often runs in families. It is caused by improper development of eye's drainage canals before birth.
Other types of Glaucoma are pigmentary, secondary glaucoma, pseudoexfoliative glaucoma, traumatic glaucoma, neovascular glaucoma and irido corneal endothelial syndrome (ICE).
The aim of the treatment is to reduce the pressure in your eyes, which involves using special eye drops or medications. In certain cases, laser treatment or surgery is performed to prevent further damage.
Laser treatment is usually recommended if the use of eye drops does not improve your symptoms. Laser treatment involves using powerful beams of light to improve the flow of fluid out of your eye and reduce the pressure inside the eye.
During the laser surgery, your eye is numbed with anaesthetic eye drops. Then, your doctor will place a special lens in front of your eye. Afterwards, a laser beam is aimed into your eye and you can see flashes of coloured light.
Types of laser surgery for glaucoma include:
Laser trabeculoplasty: Laser trabeculoplasty is often used to treat open-angle glaucoma. The laser is aimed at trabecular meshwork, where fluid drains from the eye. This surgery opens the clogged areas and makes it easier for fluid to flow out of the eye.
There are two types of laser trabeculoplasty surgery:
- Argon laser trabeculoplasty (ALT): During ALT surgery, a laser creates burns in the trabecular meshwork.
- Selective laser trabeculoplasty (SLT): During SLT, a laser is used at different frequencies to treat specific cells in the meshwork.
Laser Iridotomy: Laser iridotomy is normally performed to treat people with closed angle glaucoma. During iridiotomy, the laser creates a small hole through the iris to improve the flow of fluid from the back of the eye to the trabecular meshwork. This opening drains out the fluid and helps lower eye pressure.
Cyclophotocoagulation or laser cyclo-ablation: Laser cyclo-ablation may be helpful in treating people with severe glaucoma, which has not been manageable with medications or surgeries. In cyclophotocoagulation a laser is used to destroy the parts of the ciliary body, a part of the eye that produces eye fluid. This therapy decreases the production of fluid thus reducing the eye pressure.
Risks and complications
You may have a slight burning sensation in the eye during laser surgery. Your eyes may feel irritated and have slightly blurred vision. Rarely a short term increase or an excessive drop of intraocular pressure can also occur after laser surgery. Both of these complications can be manageable with medications. You may also have a slight risk of cataract formation after some type of laser surgeries for glaucoma.
Vitrectomy for Retinal Detachment
Vitrectomy is the surgical procedure that is widely used in the treatment of retinal detachment with large tears.
The surgery may require an overnight stay or sometimes it is done as an outpatient procedure that lasts for 2-3 hours. Vitrectomy is performed under local anaesthesia with an operating microscope. Three small incisions are made in the sclera (white outer wall of the eye) to infuse fluid in order to maintain the shape of the eye, for a fibre optic light and to insert the surgical instruments. The procedure involves the removal and replacement of the vitreous (clear gel that fills the back of the eye) with special saline solution which resembles the natural vitreous in the eye. Once the vitreous is removed, the retina can be accessed to treat the detachment by removing the scar tissue that is pulling the retina away from the underlying layers of tissue.
After the removal of vitreous gel, the fluid that has collected underneath the retina is removed to flatten the retina into normal position. Laser therapy (intense laser beam) or cryotherapy (freezing temperatures) is then used to scar and seal the retinal tear aiding to keep the retina permanently attached. A gas bubble or silicone oil is injected into the vitreous cavity (the cavity located behind the lens of the eye and in front of the retina containing the vitreous) to hold the retina in place while the scars from the laser and/or cryotherapy heal.
With newer surgical techniques and instrumentation, the surgery can be performed through tiny “self-sealing” incisions without the need for sutures. Surgical recovery generally takes about 6 weeks and vision recovery a little longer.
Treatment for Cataract
Surgery is the only treatment for cataracts and is recommended based on the severity of the disease and the impact it has on the daily activities of the patient. It is performed one eye at a time with a few weeks gap in between the two operations. The different types of cataract surgery are performed on an outpatient basis, under local anaesthesia.
Phacoemulsification uses ultrasound vibrations to break up the eye’s damaged lens. Your surgeon will make a small incision of about 3-5 mm on the side of the cornea, and insert a device to break up and suction out the lens. The lens will be replaced by a manmade lens. The incision heals on its own and does not require any eye patch or stitches. This surgery takes less than 30 minutes.
Microinscision Cataract Surgery (MICS)
Microincision cataract surgery (MICS) is a minimal invasive cataract surgery, performed by making an incision of less than 1.8 mm. The lens is removed by the phacoemulsification procedure and is implanted with a MICS intraocular lens. MICS is associated with decreased post-operative complications such as corneal aberrations (scratch on the corneal surface) and corneal astigmatism (irregular curvature of the cornea).
Secondary Lens Implantation
A complex cataract surgery or injury can sometimes make it difficult for the surgeon to immediately replace the damaged lens with a plastic lens in your eye. You may have to wear prescription lenses until your eye heals. Following this, your doctor will suggest a second surgery for lens implantation. This is called secondary lens implantation. Your surgeon will make a small incision in the white part of your eye (sclera) and insert a lens implant. The implant is stitched to the sclera and the incisions are closed with small stitches.
Small-incision Cataract Surgery (SICS)
Small-incision cataract surgery (SICS) involves an incision of around 6-7 mm made in the form of a tunnel through the sclera and cornea. The lens is removed and replaced with a rigid lens implant through this tunnel. No sutures are needed as the tiny incision will heal naturally by itself. It is a low-cost procedure compared to phacoemulsification and ensures good post-operative outcomes.