What is Phacoemulsification Surgery
What is phacoemulsification surgery?
Cataract is an opacification of the natural crystalline lens inside the eye. This opacification can cause gradual blurring of vision for both far and near distances. Cataract is removed from the eye and replaced with artificial intraocular lens that can correct far or near distance and it is called monofocal or monovision intraocular lens or it can correct far, near and intermediate distances and it is called multifocal intraocular lens.
Before the surgery the pupil should be completely dilated to facilitate the extraction of the cataract from the eye because the cataract lies behind the pupil and if the pupil is small or can't be dilated, the removal of cataract will be difficult.
Most of the time, cataract surgery is preferred to be done under topical anaesthesia with intracameral anaesthesia. Other options of anaesthesia are subtenon and retrobulbar anaesthesia. In certain cases such as in children or uncooperative patients, cataract surgery can be done under general anaesthesia.
In order to reduce the incidence of post cataract surgery endophthalmitis, 10% povidone iodine is used to sterilize the skin around the eye and also to sterilize the conjunctiva.
The natural crystalline lens is surrounded completely by elastic membrane like structure called the capsule and in order to remove the opacified lens or cataract, this capsule should be opened anteriorly or from the front part with a special forceps by a technique called capsulorhexis.
According to the stage of cataract. Cataract can be classified to soft, moderate, hard and mature cataract.
The old cataract surgery called extracapsular cataract extraction. A large corneal incision is created near the limbus (Between the cornea and the sclera). The length of corneal incision is 8-12 mm which depends mainly on the size and density of the cataract.
An opening the front part of the capsule or capsulorhexis is created and then the cataract is removed as a whole in one piece and the corneal incision is closed with nylon sutures that can be removed after 2-4 months.
Post operation Astigmatism is high in this kind of surgery because of the stitches and also visual rehabilitation is later comparing to Phaco-emulsification
The new cataract surgery is called phaco emulsification. It is a sutureless eye surgery in which small corneal incision (2-3mm) is created with small sharp knife and the hole is made in the anterior face of the capsule with special forceps .The cataract is removed by ultrasound probe that divides the cataract into small pieces that can be easily removed by aspiration.
Continuous fluid irrigation inside the eye is very important to prevent any damage to the cornea and other parts of the eye from the heat that is generated by the ultrasound. It is very important during the surgery for the iris to keep dilated and this can be done by adding Omidria injection to the irrigation bottle.
Visual rehabilitation is earlier than the old fashion extracapsular cataract surgery because it is sutureless and there is less to no astigmatism induced by the surgery.
A new technique can be used to assist in pahcoemulsification by using femtosecond laser. This laser can be used to create the corneal incision and to create the hole of the anterior face of the capsule. It can be used also to divide the cataract into many small pieces that can be easily removed by the Phaco aspiration probe with less ultrasound. After removal of the cataract, an intraocular lens is implanted inside the eye.