What Happens in a Contact Lens Exam?


Contact lenses are a great option for many people who need prescription lenses to see clearly, but who dislike the look of glasses or find them inconvenient to wear. When you choose to use glasses, you may find that you are unable to wear them when participating in certain activities, such as swimming or playing contact sports. You may also become frustrated with having to remember to take them with you if you go out anywhere. Meanwhile, contact lenses offer patients much more flexibility with their vision since they can be placed in and left it all day long, they don’t interfere with your appearance, and patients can enjoy a wider range of activities while wearing them. 


What you may not be aware of is that if you decide that you want to wear contact lenses, you will need an additional set of assessments that are combined into an appointment called a contact lens exam. 


Why is a Contact Lens Exam Needed?


Unlike glasses, contact lenses sit on the surface of the eyes rather than a short distance in front of them. This is important because it means that the prescription that is needed for patients to see clearly is different in contact lenses to what it would be in glasses. However, this isn’t the only thing to consider. Contact lenses also need to be comfortable to wear. Since every patient has a slightly different cornea, your eye doctor will need to work with you to find the right type, size, and material of contact lens so that you can wear and handle them easily. In order to find the perfect contacts, additional tests are needed. 


Elements of a Contact Lens Exam


There are various different elements involved in a contact lens exam. These include the following and your eye doctor will explain each to you in more detail during your appointment.


Corneal curve measurements


There are two techniques for performing this test – a manual process using a tool called a keratometer, or a scan of your eyes which produces a 3d image of the surface called a corneal topography scan. Both of these can provide your eye doctor with invaluable information about the size of your cornea and how regular the dome shape it. If the surface of your eyes is found to be very irregular, you will be diagnosed with a condition called astigmatism. This means that you will need a special type of contact lens to correct the shape so that you can see clearly. Most patients with astigmatism are recommended to try a type of contact lens known as a toric lens.


Iris and pupil measurements


In addition, to measuring the curve of your cornea and assessing its regularity, your eye doctor will also need to measure your iris and pupils. Your iris is the colored part of your eye, while the pupil is the small, dark-colored dot in the middle. The measurements of these and their position on the eye are carried out manually using either a handheld rule or using an instrument using a slit lamp. Again, they help to ensure that your eye doctor recommends the right size and style of contact lens to suit your eyes. 


Tear film evaluation


Your contact lenses will sit on a layer of the tear film on the front of your eye. This keeps them comfortable and makes it possible for you to take them in and out. If you don’t have enough tear film, you may need a special type of contact lens, called a scleral lens, which helps to keep sufficient tear film on the surface of the eyes and your lenses comfortable. Your tear film evaluation will be extremely simple and will involve tiny strips of paper being placed onto your lower eyelid to see how quickly it becomes moistened. 



Once your eye doctor has completed these tests, it will be possible for them to determine which contact lenses will best fit your needs. You will then move onto a fitting, which involves trying on generic prescription lenses of different types and styles until you and your eye doctor are happy with a specific variety. They can then order your lenses with your prescription, which you will be able to collect a number of days later. At this final appointment, you’ll be given all of the information that you need to take care of your contact lenses and keep your eyes healthy. 


For more information about what happens in a contact lens exam, please speak to our expert team by calling our clinic in  Seymour, IN.