What to Expect

Binocular indirect ophthalmoscopy is used to inspect the retina. However, with this technique a large area of the retina can be viewed instead of a only a small portion as seen with direct ophthalmoscopy.

The device consists of a headband, an optical viewing system, and a controllable illumination source. The lens system has eyepieces that are adjusted depending on our distance from you, the patient. A condensing lens held near your eye generates an image of the retina.

With binocular indirect ophthalmoscopy, we have the advantages of a large field of view, bright illumination, a comfortable working distance, and little periphery view distortion. Your pupils are dilated prior to performing this test.

Using special prisms or lenses in the phoropter, we will test the way your eyes aim when relaxed and your ability to point and hold your eyes on a target.

The fundus lens is another noncontact, well-illuminated, retinal evaluation procedure. The fundus lens exam uses a powerful condensing lens to produce a magnified image. For this test, we use a biomicroscope for easy illumination and viewing. Similar to the binocular indirect exam, the condensing lens is held in front of the patient’s eye. The exam produces high-quality, highly magnified, 3D views of the optic disc in addition to a detailed inspection of the posterior portion of the eye.

Eye care patients usually assume that measuring blood pressure is a general physician’s procedure. However, people generally do not visit their family doctor on a regular basis and therefore do not regularly have their blood pressure measured.

A visit to the eye care clinic should, and in most cases does, take place either annually or twice a year. Because these visits are more frequent, it has become common practice for optometrists to measure your blood pressure to detect hypertension.

Signs of hypertension may also be seen when we examine the inside of your eye. Usually, hypertension is associated with heart and kidney complications, but it affects vision as well. Screening for hypertension is an invaluable tool, because it may alert you about a potentially debilitating health or vision problem.

Color vision defects are common, especially for men. The most familiar color vision problem involves confusing reds and greens. Some patients may also have problems with colors in the blue-yellow range. The standard test for assessing color vision defects is the pseudoisochromatic plates test.

The pseudoisochromatic plates test consists of a variety of color plates in a book. The plates have different patterns—numbers, letters, figures, or a winding path within a series of dots—that vary in hue and brightness from the background. For example, one plate may have a background of orange dots and the figure will be in olive green dots. To a person with normal color vision, this is easily distinguishable, but to someone who is dichromatic, two colors appear to be the same, like red and green, and no figure will be noticeable.

We might measure the shape of the front surface of your eye (the cornea) with a keratometer, which allows us to measure the curvature of your eye’s surface. This is useful in helping detect astigmatism, fitting contact lenses, and determining the cause of decreased visual acuity, even with the best prescription glasses.

We may also use a more sophisticated device called a corneal topographer to produce a detailed map of the shape of your eye. This device is often used to diagnose certain corneal diseases, aid in contact lens fitting, and in conjunction with refractive surgery techniques.

The first part of this test is the unilateral cover test. While wearing your corrective eyewear, we will ask you to focus on a letter on the distance eye chart. Normally, with both of your eyes open, both eyes should be aimed at the point of interest. We will then cover your right eye while watching for a movement of the left eye. Upon removing the occluder, we will wait for a few seconds to allow your eyes to return to equilibrium, then proceed by covering the left eye. If the uncovered eye moves to fixate the target, that eye was not being used. This is referred to as a strabismus.

The alternating cover test is very similar to the unilateral cover test, but the occluder is switched from one eye to the next. If the just uncovered eye moves, this is called a phoria: in the resting position, both eyes are not aimed at the target. Consequently, you must use effort to keep both eyes fixated on the target. This can cause eye strain and headaches, and may require prisms in your spectacles or visual training.

We may also test your depth perception, called stereopsis. A common test for this is known as a stereo fly test. The patient wears a pair of polarized spectacles and looks at special photos, one of which is a picture of a fly. If the patient has depth perception, the fly will appear to stand off the page.

This is a very safe, noncontact examination of the inside of the eye and retina, using a small handheld device called an ophthalmoscope.

The head of the opthalmoscope contains many lenses, and it projects light through a variably sized aperture. This is attached to a handle that serves as the power source. The beauty of the ophthalmoscope is that it uses the eye as a simple magnifier producing a magnified image for us to view.

To obtain the best results from this analysis, lights in the exam room are generally dimmed, allowing the pupil to maximally dilate. If the pupil is still too small, a topical mydriatic solution may be used to aid in dilation. The doctor will then ask you to fixate on a target. By varying the lenses, the distance from your eye, and aperature size, the doctor can survey the iris, crystalline lens vitreous, retina, and optic disc.

With a penlight, we inspect the external structures of the eye, including the eye itself and the lids.

Next, we use a slit lamp bimicroscope to externally examine the eye with magnification. You will sit in front of the instrument with your head on a headrest. By adjusting the angle of illumination and magnification, we can view most external aspects of the eye in great detail.

We will ask you to focus on a nearby target and follow it with your eye as it moves. This tests the ability of your eyes to follow the target, and it will indicate any problem with the nerve supply to your eye muscles or problems with the muscles themselves.

The purpose of this test is to inspect your ability to converge your eyes. We will ask you to focus on a near target. There is a normal range at which you should be able to see a single target. As it is brought closer and closer to your nose, you will be asked when you first see two targets.

We will direct a light beam at and away from your eye, to observe if your pupils constrict and dilate as expected.

If your eyes do not focus properly due to myopia (nearsightedness), hyperopia (farsightedness), or astigmatism, we can detect and quantify these problems using various instruments, starting with the autorefractor.

The autorefractor is a device that automatically determines the correction your eyes need. We then fine tune the correction using a phoropter. You might recognize this as the instrument that is placed in front of your eyes that resembles binoculars. This part of the exam usually begins with a handheld instrument called a retinoscope, which shines a light through the phoropter and into your eye. By viewing the reflection from the back of the eye and changing the lenses in the phoropter, we can make a good approximation of the spectral correction, so that the best possible prescriptive lenses can be made for you.

After we have a good approximation of the correction needed for your eyes, you will be asked a series of questions—“Which is better: one or two?”—while we change the phoropter lenses to refine the correction. The ability to focus up close and the correction for reading are also tested. These tests are required, to avoid eyestrain and headaches, and are necessary for determining the bifocal power for spectacles for patients who are over 40 years old and have significantly lost the ability to focus up close.

This is a procedure that measures the pressure of the eye. The importance of this stems from the fact that increased pressure levels in the eye may indicate glaucoma. We can recognize glaucoma by examining the optic nerve head, but this is only after it has begun to cause damage. Monitoring the intraocular (inner eye) pressure can give us a head start on diagnosing and treating glaucoma before it causes irreparable harm to your sight.

One of the first tests that you will encounter is a visual acuity test. This is performed using a chart with rows of letters. You will be asked to read progressively smaller rows of letters until they become indistinguishable. Even if you have to guess, try to make out the smallest letters possible to help give us a good idea of your visual acuity.

If you have, for example, 20/40 vision, this indicates that what you can read at 20 feet can be read by a normal eye at 40 feet. You may take part in both distance and near vision acuity tests.

Visual field tests determine if your peripheral vision is normal. Visual field testing also can detect problems such as glaucoma and other eye diseases.

Typically, this is done with a large white bowl apparatus on which spots of light are projected. You will fixate your eye on a central spot, then indicate when you see a small spot of light off to the side. Visual field also can be tested using a screen on which a white spot is moved and the patient indicates when the spot disappears.

The Amsler Grid also tests the visual field, specifically your central vision capabilities. This test consists of a black grid on a white background with a central fixation point located in the middle. The Amsler Grid provides a fairly good barometer of the health of the macula (region of the retina responsible for our central vision).

To take the test, you will fixate on the dot in the middle of the grid. If your macula is healthy, the lines should appear straight and clear. By contrast, an unhealthy macula will sometimes view the lines as wavering or will see blank spots in some areas. These are all indicators of a compromised macula.