Eye exams

Because good vision is such an important part of life, it just makes sense to get regular checks of vision and general eye health. Vision problems often start with few signs of their existence and may only be detected by the time they become severe. Regular doctor visits not only help to show early indications of problems, but also allow a better relationship between the doctor and their patient.

Frequently people say they had a vision test which revealed they need glasses. They often don't understand the vision problem the glasses fix, they just know they have better vision again. This is sad. It is hard to know what questions to ask, but a person should really try to know what is going on with their own body. If one doctor doesn't explain the condition to you, keep trying others.

Here we will take a quick look at the kinds of eye doctors which are available and then a brief trip through a basic examination session.

Who treats your vision:

There are three main classes of people who specialize in vision care; opticians, optometrists, and ophthalmologists. These classifications are subdivided into specialty fields, such as an ophthalmologist becoming just a cataract surgeon. It is not uncommon for a patient to visit more than one person to treat a vision (or other medical) problem.

It is important to note that any one doctor will not know everything relating to a patients care. You may need one appointment for regular vision exams, another to further diagnose changes or problems, and yet another to help you obtain the best visual aid for correction. While referrals are commonplace, it is almost always up to the patient to research assistance aside from the basic follow-up as instructed.

Optician:

An optician manufactures and/or dispenses eyeglasses, contact lenses or visual aids. They are not qualified to perform real vision testing, but work with the prescription needed provided by a vision exam. They can note your vision with the visual aids to insure they work properly.

Optometrist:

An optometrist is a Doctor of Optometry (DO) trained in all areas of optics and vision science. They are qualified to give a complete vision exam and diagnose all types of vision problems. They can treat vision problems with the use of glasses, contacts, or other visual aids and (if licensed to do so) may also prescribe drug treatments. They may also refer patients to an ophthalmologist or another type of medical doctor for further diagnoses or treatment.

Ophthalmologist:

An ophthalmologist is a Medical Doctor (MD) qualified to perform complete vision tests and diagnoses. They can treat vision problems either physically (visual aids), medically (drugs), or surgically. They are qualified to also detect other possible medical problems revealed during a vision exam and refer the patient to other medical specialists.

Low Vision Specialists:

Within the optician class is a less widely known group of people called Low Vision Specialists. These are people trained to help match more powerful visual aids with those who suffer from severe vision loss. A low vision specialist knows many types of visual aids and how they work. They may perform their own style of vision testing on patients as well as get to know a patients daily needs and lifestyle. There is a wide range of devices that can assist in improving vision, but sadly most doctors who diagnose vision problems do not refer patients to obtain the visual aids which could benefit them greatly.

Just as important as picking the right type of doctor is picking the right doctor for your personal care. Doctors are people too, meaning they have different personalities, styles, and levels of training. The patient should not only trust and respect the doctor, but should feel very comfortable with the office visit. If the patient is uncomfortable or feels the doctor is not serving them well, the patient has every right to seek another doctor. Both the patient and the doctor benefit from a good relationship during the visits.

Basic eye exam:

Examinations provide two important functions for the patient and the doctor. The immediate return is a determination of current conditions and abilities of the patient. The long range benefit is that a doctor can use prior history information to determine how a known condition is progressing or to recognize gradual diminished capacity, often before a patient notices anything. Yearly exams are very strongly recommended for both children and adults, but are essential for people over 40 years old.

There are many aspects of examinations, but they are designed to check on three situations; the quality of vision, the health of the eye, and the possible presence of other health concerns. Not all vision problems are caused by eye problems and not all eye problems inhibit normal vision.

It is also interesting to note that a doctor can inspect the blood stream of the body by looking at the blood vessels in the retina. By using high powered magnification and bright light, a retinal artery examination is the only place a doctor can view the blood stream without cutting open the body. This portion of the exam may help a trained doctor to recognize the presence of some existing health problems that have not been detected previously. An eye examination is not just for the benefit of vision information.

What actually occurs at each examination depends upon many different factors. The presence of vision or eye conditions will likely increase the number or types of tests performed on a patient. If this is the first visit to a doctor, they will probably do a more complete exam (opposed to a quicker routine exam by a regular doctor) so that they may get an understanding of personal situations. An examination will also be extended if the doctor notices any change in vision or eye health from previous exams.

We will discuss some of the common aspects of an examination to give a better understanding of why each part is performed. Most doctors will explain the steps as they go along, but you should ask any questions you might have (however trivial you think they are) at the time you think about them. As the patient, you do have the right to know. Some patients also write down questions or symptoms prior to an appointment so they don't forget anything. Some even take notes during an exam for later reference.

Discussion:

Usually you will be visited first by the doctors' assistant. Often the first order of business is a causal style discussion about why the patient is there. Is it a routine visit, any new problems, any other change in overall health aside from vision, changes in lifestyle or work, etc. Patients are asked to describe (in detail) any changes and their symptoms or problems so that the doctor can deal with them.

Beyond the scope of information gathering, these interactive sessions are also used to put a patient at ease or to establish a common trust. A patient is easier to examine if they are calm and comfortable with the staff and surroundings.

The eye chart:

The first real test for the patient is the session of reading letters from the eye chart. The chart can be a physical chart mounted on the wall or some doctors use a chart projected onto a wall or mirror. If the examining room is small, the system of mirrors can help to increase the distance of the chart from the patient. Some doctors also use handheld charts with bigger type for patients with low vision. Whatever the chart consists of, the goal is still to get an idea of the visual acuity. Some doctors also use charts that have colored letters to test for colorblindness or have different backgrounds to check contrast recognition.

Normally a doctor will have you read the chart three times; once with both eyes, once with only the left eye, and once with the right eye only. Sometimes the doctor will change the chart for each test to help prevent 'cheating'. The visual acuity is recorded for each eye so that future tests may be compared to them for both eyes individually.

External exam:

Once the level of vision for each eye has been established, a doctor will perform a series of tests (in any order they choose) to determine the working condition of each eye. Results from these tests will give the doctor an insight into possible eye problems. The tests include (but are not limited to); eye positioning, visual field, pupil reaction, and outer eye health.

Eye positioning is usually checked by having the patient face forward and following an object (pen, pencil, or whatever) without moving their head. The doctor will notice if both eyes are tracking the object equally or if one eye is out of alignment. Even an eye with greatly diminished vision will track the object as long as it is able to perceive it. This test may be performed at varying distances if the patient has either nearsighted or farsighted conditions.

Visual field is tested by having the patient face forward and stare at an object directly in front of them. The doctor then slowly moves another object into view from the sides, top, and bottom. The patient tells the doctor when the object can be identified. This test is done for both eyes individually and sometimes again using both eyes. The doctor may repeat the tests several times to insure accurate results.

Pupil reaction is tested by shining a bright light into the eyes to see if the pupil quickly restricts (close) to limit the amount of light entering the eye. Each pupil should have a similar reactive time and should also open quickly again once the light has been removed.

Outer eye health tests simply consist of checking normal blinking ability, the appearance of the eyelids (if they close tightly or leave a gap), and external abnormalities such as redness or swelling. Many problems of this type will get you a referral to a medical doctor for treatment of problems not associated with the inner eye.

The biomicroscope:

With the vision and performance tests out of the way, the doctor will look at the inside of the eye. In order to do this, a device called the biomicroscope is used. The biomicroscope is a high powered magnification unit which enables the doctor to see detail of the inner eye. A vertical beam of light inside of this device can be moved around to allow the doctor to inspect any area of the inner eye which is visible from the front. Because the exam is done with this vertical beam of light, it is often referred to as the slit lamp examination.

The patient places their chin on the chin rest of the biomicroscope and the doctor looks through eyepieces on the other side of the unit. The doctor will ask the patient to look in different directions at times to obtain a view of different parts of the eye.

Sometimes a doctor will also use a ophthalmoscope, which is similar in function to the biomicroscope but is a hand held unit rather than a big machine. It uses a less intense light and offers more flexible movement options for the doctors viewpoint.

The pressure test:

Abnormally high intraocular pressure (called Glaucoma) is a very serious condition which can eventually lead to total blindness if it is not treated in a timely manner. The doctor uses a device called a tonometer to test the pressure inside of the eye. This device is usually mounted on the biomicroscope unit and the test will normally be performed right after the inspection of the inner eye.

The patient is given anesthetic eye drops (which remove pain sensitivity) and then fluorescein (a dye) is applied to the eyes. This dye coats the front of the conjunctiva during blinking. Once the patient is back into the biomicroscope chin rest, the white light is changed to a blue light and the tonometer is slowly brought forward until it touches the front of the eye. The doctor will see a pattern as the pressure of the tonometer matches the intraocular pressure.

Pressure readings can change during the day and accordingly from exam to exam. This is one good reason for having regular exams. Once a normal range is established on a patients record, a doctor can more easily determine if a notable change is occurring. If the pressure is abnormally low or high, the doctor might schedule a follow up exam to recheck the reading.

Other tests:

There may be other tests that a doctor performs due to other conditions which may be present or likely to occur. The history of the patient or family tree might encourage more in depth testing. Modern technology is producing more advanced testing devices as well as treatment options.