Initial Eye Exam for Laser Eye Surgery

After either deciding to have laser eye surgery, or even if you just want to weigh up your options, the first step in the process is to have an initial eye exam. This first exam is purely to test how suitable laser eye surgery will be for you and what type of outcome you can expect. It is also important for the doctor that they find out whether you or any of your family have any existing health or eye related problems. It is important that you answer all the questions you are asked truthfully as this can affect both your suitability and the final outcome. Below you will find the general outline of the initial eye exam.

Prior to your initial exam, the laser eye surgery clinic you have chosen will tell you to stop wearing any form of contact lenses. The time limit you have to stop wearing them for is generally:

  • Soft Contact Lenses – Don’t wear from 2 weeks before exam
  • Rigid Gas Permeable or Toric lenses (astigmatism correction) – Don’t wear for 3 weeks prior to exam
  • Hard Lenses – Must not be worn for a month prior to exam

This information is given as a purely precautionary measure. Wearing contact lenses can sometimes misshape the front of the cornea, especially when wearing rigid or hard ones. Laser eye surgery relies on reshaping the cornea to correct any vision problems. If the cornea is misshapen in any way, the initial readings of how much corneal tissue to remove during surgery can be wrong. This can lead to problems following surgery, when the adequate level of correction isn’t reached.

When you meet your surgeon, it is likely that he will be the one who is performing the operation, so it is important that you trust him and feel comfortable with his skills and experience. He will want to know a number of things about your health, which is known as taking a ‘medical history’. This is done to allow the doctor to find out if there are any reasons as to why you shouldn’t have the surgery. He will ask about:

  • Your Current general and eye health
  • Any conditions you may have – such as glaucoma or diabetes
  • Any past medical problems
  • Any types of eye procedures or surgery you may have had
  • Any family history of eye or general health problems
  • Any prescription or over the counter medicines you are taking
  • Whether you are allergic to anything

These are just a general list of questions, it is likely that the doctor will have a few more specific ones to check your overall health. Following this, sometimes the doctor may wish to take your blood pressure or BP. This is to check your overall health, as a high blood pressure can sometimes lead to eye problems.

It is natural to feel worried when you are having the initial eye exam however it really is nothing to worry about. The doctor just wants to make sure you are fit and healthy before the treatment can start.

The most vital part of the initial consultation is a thorough eye exam. To let you know what to expect please read the following bullet points. Initially the doctor will do a visual inspection of your eyes and eyelids, to check they are normal and functioning ok. He will usually then:

Test visual acuity

Visual Acuity is measured using a Snellen eye chart. It is likely that you will have seen these before at the opticians. It is a board made up of letters, starting with the largest at the top and the smallest at the bottom. The doctor will get you to read down the list as far as possible until you can no longer read the writing. This will give you are score which tells the doctor how well you can see compared to normal vision which is measured as 6/6.

Measure current spectacle prescription

This is done using a procedure called lensometry. It involves a machine called a lensometer which after positioning your head correctly, will get you to look at either letters or colours through a wide number of corrective lenses. This allows the doctor to determine the refractive power of your spectacles and how much your vision needs to be changed to get it back to normal.

Test your pupil function

It is likely that the doctor will want to check how well your eyes function in light and dark. Using a pen light, they will shine it in your eyes whilst getting you to look straight ahead. Normally both your pupils will contract when you look at bright light.

Map the cornea using wavefront technology.

If available, many doctors will get you to place your head into a machine known as a wavefront abberrometer. This is a very sophisticated machine, allowing surgeons to find any imperfections on the surface or within the cornea. With this information and the corneal topography map mentioned below, the surgeons can plan your treatment very precisely.

Measure the curve of the cornea

This is a process known as corneal topography and uses a piece of machinery that produces a picture of the front of your eye. Just like a map, it has different colours for different areas depending upon how steep the area is and any imperfections it may have. This allows the surgeons to determine how much of the cornea needs to be removed in certain areas to produce a smooth cornea, which will correct your vision.

Measure the corneal thickness

Again it is important that the surgeon has as much information about the cornea as possible. By measuring its thickness, the surgeons will then know how much tissue can be removed in various areas. This is done with a pachymeter.

Measure the Intraocular Pressure

A raised intraocular pressure can damage the eye and negatively affect your vision. Before the surgeon agrees to perform the procedure, they must make sure the vision problem isn’t due to pressure damage.

From the information of these specific tests, the surgeon will decide how suitable you are for laser eye surgery. If everything is fine and you wish to proceed with the treatment the surgeon will explain some of the possible complications of the surgery and will want to know that you understand the procedure and what it entails.

Prior to the procedure there are still a number of more accurate tests that will need to be done. These usually comprise a number of tests including:

  • Strength of the muscles of your eye
  • Check your ocular dominance
  • Check the pupils are ok
  • Checking refractive powers
  • Perform a slit lamp and tear test

This is not an exhaustive list, more a selection of what is likely to be done. If you would like more information into the eye exam please contact your local laser eye surgery clinic.

Remember however that this initial consultation is as much for you to find out about the surgeon and the procedure as it is for them to find out about you. Ask as many questions as you like, it is often best to think about these a few weeks in advance and write them down to take to the consultation with you. Your surgeon will be happy to answer your questions and explain the best procedure for you. And lastly if there is anything you or your family want or forget to ask, most laser eye surgery clinics will be happy for you to telephone them.

The following articles will begin to outline how you should prepare for laser eye surgery and what you can expect, before, during and after the procedure.

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