Eye examination involves a series of tests that can be performed with standard equipment,
including a standard ophthalmoscope or special equipment, and an evaluation by an ophthalmologist.
The ophthalmologist can use a variety of tools and exams, and each test during an eye exam evaluates a different aspect of vision or eye health. An eye examination helps detect eye problems at their earliest stage – when they are most treatable.
The history of the disease can provide information about the location, speed of installation, duration, and previous history of ocular symptoms: the presence and nature of pain, secretion or redness, and changes in visual acuity. Severe symptoms, in addition to vision loss and eye pain, are the presence of bright spots, an abundance of floating objects, diplopia, and loss of peripheral vision.
When is it recommended to go for an eye examination?
Several factors can determine how often you need an eye examination, including age, health, and the risk of developing eye problems. The general guidelines are as follows:
For children under 3 years of age, the pediatrician will probably look for the most common eye conditions in children – lazy eyes, crossed eyes, or misaligned eyes. If there are eye diseases or symptoms, an examination is appropriate at that time, regardless of age.
- every five to 10 years between 20 and 30 years;
- every two to four years, from 40 to 54 years;
- once every three years, from 55 to 64 years;
- once every two years after age 65;
The frequency of an ophthalmological clinical examination increases when the patient:
- wear glasses or contact lenses;
- has a family history of eye disease or vision loss;
- has a chronic disease that imposes a higher risk of eye diseases, such as diabetes.
Visual acuity
The first step is to determine visual acuity. Patients who require corrective lenses will wear
them during the test, and patients who do not require corrective lenses are asked to look through
a device with pinholes, which will focus the light rays and compensate for the refractive error.
The visual acuity of each eye will be tested while the other eye will be covered. The patient looks at the table from 6 m away. Refractive errors can be estimated approximately with a portable
ophthalmoscope noting the lenses needed by the examiner to focus on the retina,
this procedure requires the examiner to use his own corrective lenses and never
substitutes a more comprehensive assessment of refraction. Most often, refractive
They also measure astigmatism.
Examination of the eyelid and conjunctivitis
The eyelid and subcutaneous tissue are examined using a magnifying glass,a slit lamp,
or an ophthalmoscope at a working distance from the examiner. The lacrimal sacsare palpated
and an attempt is made to express any contents through the canaliculi
After the eversion of the eyelid, the eyelid and bulbar conjunctiva
and the fornix can be inspected for foreign bodies, signs of inflammation:
follicular hypertrophy, exudate, hyperemia, edema, or other abnormalities.
Examination of the pupil
by the rapid movement of a pen with light behind and in front of each eye
(the test of intense oscillating light). The normal response to light is bilateral, pupillary constriction, a large pupil without consensual constriction is a sign of afferent pupillary defect indicating optic nerve damage or extensive retinal disease.
Extraocular muscles
The examiner directs the patient to look in 8 different directions with the help of a moving finger, observing fixed deviations, limited movement, and/or unconjugated fixed deviations corresponding to cranial nerve palsy, orbital diseases, or other abnormalities that impede movement.
Corneal examination
The indistinct or blurred edges of the light corneal reflex suggest that the corneal surface
is not intact, excoriations or keratitis appearing on it. Fluorescein staining highlights excoriations and ulcers. Prior to staining, a drop of topical anesthetic may help to examine whether the patient is in pain or if corneal or conjunctival damage is required. A sterile, individually wrapped fluorescein strip is moistened with a drop
of sterile saline or topical anesthetic and, with the patient’s eye turned up, touched for a moment inside
the lower eyelid. The patient blinks a few times to spread the color in the tear film and then the eye
is examined with amplified blue light. Areas where the corneal or conjunctival epithelium is absent
Slit-lamp examination
The slit lamp focuses the height and width of a ray of light for an accurate stereoscopic view of the eyelid, conjunctiva, cornea, anterior chamber, lens, iris, and vitreous. It is used to identify foreign bodies,
excoriations and to measure depth, and identify inflammation or cells present in the anterior chamber.
At the same time, the ciliary current can be identified,
the inflammation located in the region
of the tongue above the ciliary body, which leads to uveitis and scleral edema, which appears
the conjunctiva and is usuallya sign of sclera.
which measure the iridocorneal
angle and require special lenses.
Visual field testing
- By direct testing, the patient must keep his gaze fixed on the examiner’s eye or nose. The examiner uses a target from the peripheral visual field, which he brings in the four visual quadrants and asks the patient to indicate when he first sees the target.
with more accurate tools. - Exact methods include using a “tangent screen” or computerized automatic perimeter.
Examination of colored vision
called pseudoisochromatic plaques. The patient is asked to look
for numbers among the different colored dots. People with normal color vision see a number, while those with disabilities do not see it. On some plates, a person with normal color vision sees a number, while a person with a disability sees a different number.
Pseudoisochromatic testing of plaques can determine if there is visual impairment and the type of deficiency.
and degree of color deficiency.
A person may have poor eyesight and may not be able to recognize it. Quite often, people with red-green deficiencies are not aware of their problem because they have learned to see the “right” color. For example, the leaves of the trees are green, so I call the color I see green.
Also, parents cannot suspect that their children have the condition until a situation causes confusion or misunderstanding. Early detection of color deficiency is vital, as many learning materials rely heavily on color perception or color-coding.
Ophthalmoscopy
fixed ophthalmoscope with portable lenses.
Direct ophthalmoscopy.
The healthcare provider performs this examination using a light beam through the pupil using an instrument called an ophthalmoscope. An ophthalmoscope is the size of a flashlight. It has lenses of different sizes, which allow the supplier to see the back of the eyeball.
Indirect ophthalmoscopy.
The patient will lie down or sit in a semi-inclined position. The examiner keeps the eye open while introducing light into the eye using a tool worn on the head. (The instrument looks like a miner’s flashlight.) The examiner sees the back of the eye through a lens held close to the eye.
using a small, blunt probe.
Slit-lamp ophthalmoscopy.
The examiner will use the microscope side of the slit lamp and a tiny lens located close to the front of the eye. Thus, he can see as much with this technique as in the case of indirect ophthalmoscopy, but with greater magnification and precision.
Ophthalmoscopy can detect crystalline or vitreous opacities, determine the optical-disc ratio and identify retinal and vascular changes. The optic cup is a central depression, and the optic disc is the area of the entire optic nerve, the increase in the proportion between the cup and the disc represents the loss of ganglion cells, a situation encountered in glaucoma.
- viral inflammation of the retina;
- diabetes ;
- glaucoma;
- high blood pressure;
- loss of acute vision due to age-related macular degeneration;
- eye melanoma ;
- optic nerve disorders.
It can detect the early stages and effects of many serious diseases. For conditions that cannot be detected by ophthalmoscopy, there are other techniques and devices that may be helpful.
Risks of ophthalmoscopy
The test itself does not involve any risk. In rare cases, dilated eyes cause:
- a narrow-angle glaucoma attack;
- dizziness;
- dry mouth;
- nausea and vomiting;
Tonometry
Tonometry measures the pressure of the fluid inside the eye ( intraocular pressure ). This is a test that helps the ophthalmologist detect glaucoma, a disease that damages the optic nerve.
Applicable tonometry
This test measures the amount of force required to temporarily flatten a part of the cornea. Using the slit lamp, the doctor moves the tonometer to touch the cornea and determine the eye pressure. Because the eye is numb, the test does not cause any pain.
If the eye pressure is higher than average or the optic nerve seems unusual, your doctor may use a different instrument. It uses sound waves to measure the thickness of the cornea. The most common way to measure the thickness of the cornea is to put an anesthetic drop in the eye, then use a small probe in contact with the front surface of the eye. The measurement takes a few seconds.
The usual results of an ophthalmological examination include:
- good peripheral vision;
- ability to distinguish various colors;
- structures with normal appearance of the external eye;
- absence of cataracts, glaucoma, or retinal disorders such as macular degeneration.
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