ISTENT - MIGS PROCEDURE COMBINED WITH CATARACT SURGERY
What is iStent (Trabecular Micro-Bypass Stent)?
iStent is an elegant way to help reduce intraocular pressure for patients with open angle glaucoma. It is the world’s tiniest medical device – it is 20,000 times smaller than the intraocular lens (IOL) that you will receive as part of your cataract surgery. It works by increasing your eye’s ability to drain fluid, thereby safely lowers your eye pressure towards a level that will prevent damage to the optic nerve.
iStent procedure is performed at the end of a cataract operation. The procedure adds approximately 5 minutes to the cataract operation. During the operation, your surgeon will insert two small iStents into the parts of your eye that drains fluid called trabecular meshwork. The procedure is painless. The post-operative recovery from a combined cataract + iStent operation is almost identical to having cataract surgery alone.
Successful cataract surgery will improve the vision in the eye. Major advances have been made in the way cataract surgery is performed over the last 10 years. Your surgeon will use the most modern techniques: the cataract is broken up (using ultrasound energy) and removed from the eye through a very small incision (cut) and a new flexible lens is inserted. This results in rapid visual recovery with minimal discomfort following the procedure.
While cataract surgery by itself has been shown to have a small short-lived effect on lowering intraocular pressure, the addition of iStent will allow better intraocular lowering for longer period of time. In US clinical study 68% of patients who received iStent remained medication free at 12 months, while sustaining a target pressure of ≤ 21 mmHg compared to 50% of patients who underwent cataract surgery alone.
What does the surgery involve?
iStent + Cataract surgery is usually performed as an out-patient basis under local anaesthetic. Since you will be unable to drive after your surgery, it is important that you arrange your own transport on the day of the surgery.
The surgery involves removing the cataract (cloudy lens) through a small incision (cut) and replacing it with a clear acrylic lens implant. The lens implant stays in place throughout your life and does not require replacement. The operation takes 20-30 minutes. Usually the incision is so small that it does not even require stitches.
Cataract surgery under local anaesthetic is not painful although you may feel a sensation of pressure in the eye at some stages during the operation. A sterile cover will be placed over your face and the other eye to keep the area clean, but it will be kept clear from your nose and mouth by a stand with circulates fresh air. Your eye will be kept open using a special instrument, so you don’t have to worry about keeping the eye open yourself. It is important that you don’t move suddenly during the operation. The bright microscope light prevents you from seeing what is going on and many patients see whorls of blue or purple light during the operation. The surgeon will discuss the way to communicate with him/her: you may choose to hold a nurse’s hand which you can squeeze if you need to communicate with the surgeon. If you feel you need to cough or sneeze you can tell us this, but take care not to move your head until the surgeon says it is safe to do so.
After the cataract surgery procedure is complete, your surgeon will tilt your head approximately 30 degrees from the center. This is done so as to improve visualization of the trabecular meshwork required to perform iStent insertion. This will only last approximately 5 minutes.
Things to look out for after operation
Do not rub or put pressure on the eye.
To clean your eye lids, clean gently with a clean moist face washer while keeping your eyes closed.
Do not get soap or water into your eye.
Do not shampoo your hair for one week.
Wear sun glasses outside, preferably with side shields.
Avoid dusty areas.
Sleep with the plastic shield taped in place for one week. Try not to sleep on the operated side.
Do not drive for one week.
Do not vacuum the house for 2 weeks after the surgery.
No swimming or hydrotherapy for 4 weeks after surgery.
Avoid strenuous activity and heavy lifting for 4 weeks.
Please bring your eye drops with you to all your post operative appointments.
Possible complications after surgery
Minor post operative complications or problems, including:
an increase of pressure within the eye, occur infrequently in the first week or so following surgery. These are usually temporary, easily treatable and do not affect the long-term visual outcome after surgery.
Small amount of bleeding in the front part of your eye (anterior chamber) which rarely can occur following iStent surgery. This blood will not affect long-term visual outcome after surgery and generally clear by itself in one to two weeks.
Prolong inflammation following operation which can cause fluid development in the retina at the center of vision (cystoid macular oedema). These are usually resolves with treatment with steroid medication and do not affect long-term visual outcomes of surgery.
Major complications: the most serious complication that can occur is an infection within the eye (endophthalmitis). This usually occurs within the first week after surgery and affects less than 1 in 1000 patients. It can lead to an irreversible loss of sight in the operated eye. The risk of infection is reduced by the use of antibiotics during and after the operation, by treating any lid inflammation prior to surgery and keeping the eye clean following the operation.
You will be advised regarding any measures you can take to reduce your risk of infection after surgery at the pre-assessment appointment.