April 26, 2011

Comprehensive Eye Exams

A comprehensive eye examination is more than coming in for a pair of prescription eyeglasses. MPO Eyecare stresses the importance of comprehensive eye examinations as this process could save more than your vision. According to studies, 75% of the world’s blindness is preventable! It is because of comprehensive eye examinations that these diseases and infections can be found before any irreversible effects occur.

Dr. Scott Lam is extremely meticulous with your comprehensive eye examination as he focuses on protecting your well being. The time spent with your eye doctor may vary from patient to patient but it is our desire to carefully examine your eyes. From simply looking at them, your eye doctor is able to predict whether you may be at the risk for diabetes, multiple sclerosis, hypertension, stroke and heart disease. Rest assured because Dr. Scott Lam is an experience optometrist that will use an array of tests to examine your eyes such as those listed below.

Visual Acuity Test

Standard visual acuity test at MPO

Visual Acuity Tests
A visual acuity test is performed to measure the ability of your eyes to read a chart. The projected eye charts measure distant reading and the hand-held ones measures your near vision. This is by far the most recognizable test from the comprehensive eye exam.


Color Blindness Test
Another test that is screened early on in the eye examination is for color blindness. This test will detect hereditary color vision deficiencies as well as to alert your eye doctor of possible health problems that may affect your vision.

Cover Test

Performing a simple and effective cover test

Cover Test
To check how your eyes work together, your optometrist will employ a simple cover test. During the cover test, your eye doctor will ask you to focus on a small object across the room while covering one eye. Once you have fixated on a target, the other eye will be covered and the test will be repeated to see if your eyes move to the target. This test will be repeated again for an object that is closer. The cover test is to indicate certain eye problems such as strabismus or amblyopia (aka Lazy Eye).


Part of the comprehensive eye examination, retinoscopy is a test to attain the approximation of your eyeglass prescription. In a retinoscopy test, the eye examination room lights will be dimmed and you will be asked to stare at the big letter E on the chart. As you fixate your eyes on the big letter E, your eye doctor will shine a light at your eye and flip the lenses in a machine in front of your eyes. Based on the way light reflects from your eye, your eye doctor can typically gauge the prescription that is required.

Manual Refraction

Manual Refraction

This is a test that will exactly determine your eyeglass prescription. For the duration of the refraction test, the eye doctor will use an instrument called a phoropter in front of your eyes and will ask you to look at a series of lenses. You will then be asked which one of the two lenses look clearer. Your optometrist will fine tune the power of the lenses until it reaches your optimal eyeglass prescription. Simply put, the refraction determines your level of hyperopia, myopia, astigmatism, and presbyopia.


Autorefractors and aberrometers
Another tool to determine your eyeglass prescription is the autorefractor or aberrometer. With these devices, you will be asked to rest your chin on a chin rest to stabilize your head while you look at an image or a pinpoint of light.

Optometrist Autorefractor

Dr. Scott Lam utilizing an autorefractor

Much like a manual refractor, an autorefractor determines the lens power required to accurately focus light onto your retina. This device is extremely useful for young children who may not sit still, pay attention or interact with your optometrist. It may be more and more likely to see this device used as modern autorefractors are very accurate and saves time during the comprehensive eye examination.


An aberrometer uses advanced wavefront technology to detect obscure vision errors based simply on the way light travels through your eyes. This type of machinery is typically used for custom wavefront LASIK eye correction procedures so it may not be found in all optometry locations.

Slit-lamp examination
A slit lamp, also called a biomicroscope, is used to examine the health of your eyes. It magnifies your eyes in order for the eye doctor to thoroughly evaluate the health of your eyes and to look for any signs of infections or diseases.

Your optometrist, such as Dr. Scott Lam from MPO, will first examine the structures from the front of your eye which include the eye lids, cornea, conjunctiva, iris, and more. Then, with a special high-powered lens, your eye doctor will view the inside of your eye which includes the retina, optic nerve, macula, and other important areas.

This particular test in your comprehensive eye examination may reveal a wide range of eye conditions and diseases such as; cataracts, macular degeneration, corneal ulcers, diabetic retinopathy, etc.

Glaucoma Test (tonometry)
A glaucoma test is often performed with your comprehensive eye examination. This test, as well as others, is important to have done because glaucoma is a type of optical nerve disease that can leave someone blind within a week.

There are two types of glaucoma tests, the non-contact tonometry and applanation tonometry test. You can find more about glaucoma and these two tests by going to our “what is glaucoma”page.

Pupil Dilation

Dr. Lam using drops to dilate your eyes

Pupil Dilation
The pupil dilation test is an important portion of your comprehensive eye examination. It is extremely useful for individuals with risk factors for eye diseases because it allows the most thorough evaluation of the inside of your eyes.


To do this, your eye doctor will utilize dilating drops to enlarge your pupils. It will take approximately 20 to 30 minutes before the drops begin to work. When the effects begin to start, your eyes will be very sensitive to light and you may have trouble focusing on close objects. The effects may last for several hours; therefore, sunglasses are recommended when you come in for your comprehensive eye exam.

Visual Field Test
If need be, you may be tested for the possibility of blind spots in your peripheral or side vision with this visual field test. These blind spots can be caused by diseases such as glaucoma, an optical nerve disease.

More importantly, a deep analysis of blind spots may also help identify specific areas of brain damage caused by a stroke or tumor. A comprehensive eye examination should be done once a year to be on the safe side.