Cataract-Causes, Symptoms, its Types and Operations


 Contents
  • Overview.
  • Etiology and risk factors of cataract.
  • Grading.
  • Symptoms of cataract.
  • Complications of cataract.
  • Management consideration.
  • Types of surgery.
  • Listing for Cataract Surgery: practically what you do when you list a patient for cataract surgery.
  • Post-operative monitoring. 


Overview

Cataract

Cataract refers to an opacification of the natural crystalline lens. It is the commonest cause, of vision impairment worldwide.

Almost everyone gets a cataract as you grow older. For patients about 60, studies estimate probably to be in the range of 50% or so. In fact, According to WHO, the 38 million people who are blind, half of them are blind due to cataracts. It's really a lot of reversible, or treatable vision impairment.

In Singapore, studies have shown that about 34% over the age of 40 have cataracts that are visually significant and 0.5% of them, in fact, is blind from the contract, or have poor vision because of cataracts from the (Tanjong Pagar Eye Study).

The commonest cataract we see is a senile version, not a cataract due to old age.



Cataract in eye , Cataract eye, white eyelens, Intumescent cataract
Cataract
Image Source-Wikipedia | Image By- Imrankabirhossain


Etiology or Causes of Cataract

Acquired Causes includes:
1. Senile.

2. Traumatic.

3. Associated with systemic diseases:
  •   DM.
  •   Myotonic dystrophic.
  •   Uveitis.

4. Drug Use:
  •   Steroid+TCM.
  •   Chlorpromazine.


Congenital Causes includes:

  • Idiopathic.
  • Hereditary and developmental.
  • Metabolic.
  • Infective(TORCHES).
  • Tumor(e.g. retinoblastoma).


Risk factors

  • UV radiation—history of exposure to UV radiation.
  • Diabetes Mellitus.
  • Use of steroid medicines.
  • Previous eye injury.
  • Alcohol consumption.
  • High myopia tend to have cataracts according to some studies, course a family history.


Types of Cataract

The commonest types of cataracts we see are:
  • Cortical.
  • Nuclear sclerotic cataract.
  • Posterior subcapsular cataract (PSC).

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Types of Cataract

Cortical, that is basically in a peripheral, sort of thing like a smoke-like appearance.
You can see this patient has a bit of a C3, 4 plus grade cortical cataract.

Nuclear sclerotic cataract It's like the dense nuclear core getting browner with time, getting yellow over time.

Posterior subcapsular cataract (PSC).

This is typically, even a little bit of posterior subcapsular cataract can tend to be quite visually bothersome for the patient. So this repeated right, as the name suggests, in the posterior subcapsular area.
So the lens is held in the capsule, and this right in the center, in the posterior aspect of the lens, adjacent to the capsule.

Rarely patients have a posterior polar cataract. That's a different sort of cataract, which you need to be a bit more worry about, wherein the capsule is involved. wherein the cataract sort of extends, or is very adherent to the posterior capsule. And they may have an onion ring, and in some cases it's bilateral. That is different from the posterior subcapsular, and that needs to be approached a bit more carefully.


Symptoms and Complications

  • Most patients as they grow older will get cataract, but many of them tend to be asymptomatic.
  • Some patients complain of gradual onset blurring of vision.
  • Some patients also complain of index myopia: Basically, they will find that the degree is changing with time. They seemed to get progressively worsening myopia. And this tends to happen to patients with nuclear sclerotic cataracts. 
  • Some patients may complain of glare, and this also typically happens in patients with cortical or posterior subcapsular cataracts.


Complications

Cataracts can also cause complications, for example,
significant—Cataract can result in secondary angle-closure glaucoma. For example, phacomorphic glaucoma is glaucoma wherein it's an intumescent cataract or very thick cataract, resulting in angle closure.
  • Phacolytic.
  • Phaco-anaphylactic.
  • Pacolytic cataract.
Pacolytic cataract, for example, occurs when-- it happens in a mature cataract, where a lens particle is able to diffuse through an abnormal capsule into the anterior chamber, inciting inflammation resulting in sort of a uveitic picture, along with the cataract. And the only treatment for this is to control inflammation and subsequently remove the cataract.

Phaco-anaphylactic, wherein there's a breach in the capsule due to trauma or due to surgery, resulting in inflammation and sometimes glaucoma.

Management

How do you manage patients?
  • Conservative if patient coping well with vision.
  • Patients complaining of index myopia, as a temporizing measure, we could just suggest glasses to change the degree.

But however, if the degree changed quite rapidly and the patient is quite uncomfortable with this a new vision or the patient complains of anisometropia or a change in degree-- because of both eyes and that's causing him significant problems in his day to day life, or quality of life--then a cataract surgery might be mandated.

So basically when would you consider surgery?

  • If the patient's quality of life is affected by his visual symptoms.
  • If there are, of course, complications, like lens-induced glaucoma, or if there's a cataract obscuring the view of the fundus. For example, many patients with diabetic retinopathy or with diabetes require DR are screening. So if the cataract's significance to obscure the view of the fundus for us to do a proper screening, it might be a good idea to consider cataract surgery.
Of course, congenital cataract is a whole new ball game, a different sort of ball game. You need to do early surgery. This needs to be managed well by the pediatric ophthalmologist to maximize vision potential of the eye, and do early surgery to maximize-- to try to correct the error, the problem.

Different Cataract Surgeries:-

Surgical options include
  • Phacoemulsification.
  • Extracapsular Cataract Extraction(ECCE).
  • SICS.
  • Historical options


1. Phacoemulsification, which is the commonest performed surgery in the developed world for cataracts.
It typically uses a 1.8 or 2.75 mm corneal incision and we inject a foldable intraocular lens implant into the bag, subsequent after removing the cataract and that enables quick visual rehabilitation for the patient.

The good part about phacoemulsification is that the wound is very small, the capsule is intact. How we do this is by emulsifying the lens, by breaking the lens into multiple fragments, and using a probe to be able to suck out the lens fragments.

2. ECCE is basically Extracapsular Cataract Extraction, wherein we manually extract cataract from the back, and we replace the lens through an incision that we create on the cornea, on the cornea limbus. And subsequently, stitch up the incision.
For ECCE, we remove the entire nucleus in one block, basically by creating a capsulotomy through a corneal incision.

3. SICS is another type of surgery did they do in the developing world, which is like ECCE in the sense that it's a mechanical extraction of the cataract, by creating a scleral incision with a self-healing tunnel, accessing the anterior chamber and then removing the lens, removing the cataract from the capsule and inserting a lens back into the capsule.
And the only unique point about SICS, as opposed to ECCE, is that it does not require suturing, because the wound created as a self-sealing wound, a scleral tunnel.

4. Historical options include couching, which we don't practice at all, and ICCE.
The difference between ICCE and ECCE are that in ICCE they remove the entire bag capsule, entire capsule lens complex. In ECCE, we just make a capsulotomy, anterior capsulotomy access the lens through that, remove it, and replace the lens within the intact capsule. Of course. this results in better visual recovery and prognosis because you can physiologically place-- you can place pseudo--the intraocular lens implant in its physiological location.


Listing for Cataract Surgery

  • When you list a patient for cataract surgery and after discussing the patient, you need to be able to tell the patient that of course, It is for his eyes. So he needs to be medically fit. 
  • Because any surgery can induce physiological stressors. Typically we tend to wait for about six months, prior to considering surgery for the eye.
  • For patients with multiple medical co-morbidities, you might want to check in with the cardiologist or the treating physician, as a medical fitness operation.