Pre-surgery Testing - Know The Importance!

Any patient who needs to undergo cataract surgery must be evaluated in a thorough manner so as to establish the requirement, appropriateness, expected surgical problems, expected benefits and co-morbid conditions having an influence on cataract surgery.

The preoperative assessment consists of--

A test for your existing glasses prescription:

It is useful for your cataract surgeon to know your existing glasses prescription in cases where there is a high refractive error (people who are very short or long sighted), in order to plan to correct this error after cataract surgery.

A full ocular examination: This includes looking at-

• The eyelid anatomy and inflammation.
• The state of the tear film, dry eye changes could make surgery difficult
• The presence of abnormalities in the cornea that could make visualisation of the cataract difficult during surgery.
• The amount of dilation the iris undergoes with dilating drops.

The type of cataract. Soft cataracts can be aspirated. Hard cataracts need more ultra-sound energy and surgical time to break up and remove. White cataracts may need trypan blue staining to visualize the capsule.

The measurement of intra-ocular pressure. With this test, we aim to exclude glaucoma and ensure optimal control of immediate pre-operative and intra-operative eye pressures often with extra eye drops that temporarily lower eye pressure.

Biometry Tests

This is a simple pre-operative measurement. It calculates the correct power of artificial intra-ocular lens. They will be implanted into your eye once your cataract is removed.

Corneal Topography

This is a test to map out the corneal curvature in greater detail. It is used prior to premium IOL Implantation like Toric IOLS either monofocal or multifocal , to ensure avoid postoperative refractive errors. This extra test is only required if the biometry readings show larger than normal differences in keratometry readings.

Optical Coherence Tomography (OCT)

This test allows detailed visualisation of the macula (the central sensitive part of the retina used for fine vision). If the ophthalmologist suspects any macula changes that may prevent a patient from visual improvement after cataract surgery, he always suggest optical coherence tomography.

Blood Pressure Measurements

It is very important to know your blood pressure measurements before your cataract operation. The risk of having a bleed at the back of your eye during cataract surgery (supra-choroidal haemorrhage) is very small (1 in 10000). But is higher if you have uncontrolled blood pressure.

Blood Sugar Measurements in Diabetic Patients

Cataract surgery itself does not affect your blood sugar measurements if you are diabetic. A routine checkup of blood sugars in diabetics before cataract surgery is done and the surgery if often delayed if the levels were greater than 20mmol/L as the risk of post-operative infection is higher. In case you have a concern or query you can always consult an expert & get answers to your questions!