Ophthalmological examination – how does it work? Do I need a referral for an ophthalmological examination?

An ophthalmological examination consists of a series of tests that allow you to assess your eyesight. Most often it is performed as part of a routine visit (in people over 50 years of age it should be performed once a year) or as part of tests ordered by an occupational medicine doctor (depending on the profession). They are always performed by an ophthalmologist. A visit to this specialist does not require a referral.

Ophthalmological examination – how is the examination performed?

During your first visit to an ophthalmology office, your doctor will ask you about your general health, chronic diseases (e.g. diabetes, hypertension, heart disease), operations and medications you are currently taking, as well as about the presence of eye diseases in your family.

Ophthalmological examination – assessment of visual acuity

One of the most important ophthalmological examinations is visual acuity test. To do this, the doctor will ask you to read successive letters from the board (the so-called Snellen table), located at an appropriate distance from the place where you are sitting. There are rows of letters of various sizes on the board, and the font size decreases towards the bottom of the board. Your doctor will ask you to read the smallest visible row of letters without corrective lenses. On this basis, the ophthalmologist will assess your visual acuity (taking into account the size of the letters, the distance from which they were read and comparing your result with that of a person with normal vision).

This type of eye examination is often performed in schools or workplaces. Before starting an ophthalmological examination, remove glasses or remove contact lenses. Then you should cover one eye, e.g. with your hand (left eye with your left hand, right eye with your right hand) or a piece of paper. Both the covered and uncovered eye should remain open at all times. It is not necessary to prepare in advance for an ophthalmological examination.

Visual acuity testing is part of a routine eye examination, especially in situations where your vision has deteriorated or has any other vision problem. In children, this test is performed routinely to check for possible visual disturbances. Drawings of objects familiar to the toddler are used instead of letters. In young children, vision problems can often be corrected. If left untreated, however, they can result in irreversible visual disturbances.

Ophthalmological examination – correct results

The visual acuity test result is expressed as the ratio of two values. The first is distance, from which the letters on the board are read – usually it is 5 m. The second value determines the distance from which the smallest row of letters that you have managed to read can be read by a person with correct eyesight. Thus, a score of 5/5 determines the best possible result, which is correct eyesight. In turn 3/5 shows that a row of letters that you can read from a distance of 3 meters, a person with correct eyesight can read from a distance of 5 meters.

What does an abnormal eye test result mean? Based on the abnormal test result, your doctor may recommend that you wear corrective glasses or contact lenses, or refer you to more detailed examinations.

Ophthalmological examination and visual field examination

The visual field examination during an ophthalmological examination can be performed in several ways:

1. The confrontation test is one of the most commonly used basic tests of this type. During the examination, one eye is covered (e.g. with a hand, a piece of paper). Then the doctor sitting in front of you will show you the fingers located in the so-called peripheral field of view (i.e. fingers of an extended arm extended to the side). He will ask you to look ahead (it is best to choose one point that you will be staring at throughout the research). The doctor will ask you how many fingers you can see at the moment.
2. The Goldman method of visual field examination has a slightly different course. While you are staring at one point in front of you, the physician moves the selected object out of the peripheral field of vision closer and closer to the point you are looking at. Based on the obtained results, the ophthalmologist prepares your map of peripheral vision. No prior preparation is necessary for the examination. This method allows you to observe only large changes in the patient’s field of view. Perimeters and campimeters are used to conduct more detailed research.

Ophthalmological examination and determination of the type of vision defect

When choosing glasses for people with visual impairments using Snellen Chart, the ophthalmologist uses a number of trial lenses and special spectacle frames. Thanks to this, he can make the appropriate correction – so that you can see clearly during the examination. This can be quite difficult with complex vision defects. Therefore, the doctor uses additional methods of examination, the so-called skiascopy or computer refractometry.

Ophthalmological examination and skiascopy

The ophthalmologist uses a flat mirror with a hole in the center and test lenses for the sciascopy. During the examination, looking through the hole in the center of the mirror, the ophthalmologist projects the reflection reflected from the light source towards the examined eye and observes the red glare from the fundus. The analysis of the displacement of these reflections in relation to the mirror allows to determine the type of visual defect, i.e. whether the eye is nearsighted, hyperopic, or whether there is astigmatism.

Setting the correct, correcting eye defect correcting glass in front of the examined eye results in an even reflection from the fundus of the eye that does not shift when the mirror is moved. The optical value of the glass objectively determines the size of the visual defect.

Sciascopy is a test that complements the visual acuity test. It is usually used in children and people with whom contact is difficult.

Refraction test

Refraction it is the ability to adapt the eye to look at objects near and far. A quick and objective assessment of the refraction of the eye is possible thanks to the use of computer refractometer. Automatic refractometry, i.e. computer eye examination can be performed on the patient without prior preparation. The test takes a very short time (several seconds), and the result, in the form of a printout, is ready to be transferred to the prescription. However, the physician can verify the refractometric result based on additional information such as the patient’s age, occupation, and other underlying eye conditions.

The refractometer, although equipped with a microprocessor, is not a computer. It is not used to analyze or assess the organ of vision, nor does it detect eye diseases – it only shows the size of the defect and its type: hyperopia, myopia or astigmatism.

In addition to skiascopy or computer refractometry, your doctor must also check your visual acuity using Snellen charts and test glasses. You should always confront the result of a skiascopy or refraction measurement on a computer apparatus with your individual feelings and the tolerance of the selected corrective lenses.

Ophthalmological examination – viewing the front part of the eye

First, the doctor performs a macroscopic examination of your eye, i.e. the eyelids, conjunctiva and the anterior segment of the eyeball look like. No devices are used for this purpose. The next stage is the so-called slit lamp. To do this, the doctor will ask you to rest your chin and forehead on a special support and look for a few seconds at one point in front of you.

A slit-lamp examination can detect eye diseases such as:

1. cataract
2. corneal damage
3. dry eye symptom
4. degenerative changes in the eye macula
5. detachment of the retina.

Ophthalmological examination and fundus examination

The examination of the fundus during the ophthalmological consultation is extremely important because it allows you to recognize the majority of eye diseases, especially:

1. retina (detachment of the retina, diseases of the macula, retinal haemorrhage),
2. uveal membrane (inflammation, cancer),
3. the optic nerve (inflammation, glaucoma) and the vitreous body (cloudiness).

The use of fundus examination is not limited to the diagnosis of eye diseases. It is also used to assess the severity of many common diseases, such as hypertension, diabetes, and atherosclerosis. It is performed with an ophthalmoscope (a magnifying glass equipped with a light source). It is one of the most commonly used “bloodless” methods for assessing the tiny blood vessels of the eyes.

Before the examination, the doctor may recommend that you put atropine drops into one or both eyes, which will dilate the pupils and make it easier to see the fundus. In healthy people, atropine may, for some time, make it difficult to read or look freely, but it does not impair vision. Since the effect of atropine does not diminish immediately after the end of the test, it is worth asking your doctor about the possibility of driving vehicles before starting the test.

Ophthalmological examination – measuring eye pressure (tonometry)

The simplest, but at the same time the most subjective, method of assessing intraocular pressure is to assess the tension of the eyeball by pressing the fingers. However, only a physician with extensive experience can tell whether the blood pressure is elevated or within the normal range in this way. Therefore, today, special instruments are used to measure intraocular pressure – tonometry.

The only disadvantage of this test is the need to touch tonometrem Your eyeball. Just before the examination, your eye will be numbered with drops or a suitable spray. Nevertheless, some defensive reflexes (escape of the eyeball from an approaching object) may be preserved. The anesthetic effect persists for some time after the test. It does not impair vision – however, be careful not to accidentally damage a less sensitive eye during this time (e.g. by hitting the eyeball with your finger).

In some offices, non-contact tonometers are already available. Examination with their use is painless and does not require the use of anesthesia of the eyeball.

Normal intraocular pressure should not exceed 21-22 mm Hg. However, there are people whose blood pressure is higher than 22 mm Hg and those who have it well below the normal level, i.e. 12-15 mm Hg.

Years ago, finding high blood pressure equated to diagnosis of glaucoma. Currently, views on this have changed. Intraocular pressure is still a very important risk factor for glaucoma. Therefore, the values ​​remain at the above levelj 28-30 mm Hg usually indicate this disease. However, it should be remembered that glaucoma can also be diagnosed when the intraocular pressure is within the so-called normal (15-20 mm Hg)and even when it is low. Glaucoma is an insidious and complex disease, and its diagnosis requires other specialist ophthalmological examinations.