COUCHING

• Earliest form of cataract removal 

• Instead of replacing the cataractous lens, it is moved inferiorly to the vitreous cavity, away from the optic axis

 

INTRACAPSULAR EXTRACTION

• Introduced in the 19th century 

• Lens was removed, keeping the capsule intact

• Risk of ocular inflammation and visual loss

 

EXTRACAPSULAR EXTRACTION

• Currently used

• Posterior portion of lens capsule is kept in place

• IOL replaces the crystalline lens

• Carried out without phacoemulsification 

• Whole lens nucleus is delivered through an 11mm incision between the cornea and sclera

 

1967: PHACOEMULSIFICATION 

• Process developed by Charles Kelman

• Method that degrades the lens using ultrasound waves

• It is a commonly preferred procedure of cataract extraction

 

LENS REMOVAL & IOL IMPLANTATION TECHNIQUE:

 

1). PARACENTESIS 

• ​A paracentesis is made in the peripheral cornea, distanced away from the main surgical incision, using a 15 degree angle blade

• The main incision measures around 2.75mm

 

 

 

 

 

 

 

 

 

 

 

 

 

2). CCC

• Continuous curvilinear capsulorhexis (CCC) process - using forceps to create a tear in part of the anterior lens capsule 

• A flap is created with anterior capsule, and is grasped via forceps to maintain control on the degree of the tear

• If the flap opening becomes too large, it may allow the IOL to become displaced

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.) PHACOEMULSIFICATION

• The next step is to emulsify the lens using a high frequency ultrasonic hand-piece with a titanium or stainless steel tip, known as a ‘phaco probe’

• The fragments produced as a result of the high energy is aspirated via a pump through the hollow probe tip.

• The next step is to disassemble the nucleus via a ‘chop’ technique and is aspirated via a vacuum, along with the soft outer lens cortex

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4). IOL INSERTION

• After the removal of the cataractous lens (or to correct a refractive error/ presbyopia), a new intraocular lens is inserted.

• Typically, a posterior-chamber lens is used, and placed either inside the pre-existing capsular bag, or sometimes in the ciliary sulcus.

• It is fixed in place via tiny projections known as haptics 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Mostly, all cataract surgery patients are administered with a local anaesthetic, allowing them to return home the same day.

• The eye will be considerably recovered in a week, completely recovered in a month

 

 

 

 

COMPLICATIONS

• Months/years later some patients posterior capsular opacification (PCO)

• Here, the capsule becomes opacified behind the IOL and is treated via a YAG laser                                   (Nd: YAG laser capsulotomy), creating a hole in the capsule.

• This allows for vision to be restored 

 

 

 

 

FURTHER DEVELOPMENTS

• A femtosecond laser has been introduced, where the patient,                                                           under anaesthetic, undergoes a similar procedure where an                                                                           incision is made in the cornea, capsulotomy is carried out and the                                                     cataract is broken up, thus allowing for an IOL to be transplanted

 

• This laser technology uses the process of photodissection,                                                               where its ultrashort pulses are focused so any collateral and heat-                                                 induced damage to surrounding tissues is eliminated