All you ever wanted to know about eye examination before eye surgery in Iran from A to Z
Periodic eye exams are essential for everyone, regardless of a person’s age or physical health. Exams are necessary for adults to determine prescriptions for eyeglasses and help with an early diagnosis. A comprehensive eye examination should be performed every two years for people aged 40 and older. Eye exams are necessary to evaluate the development of a child’s vision in their childhoods. The periodic vision testing for children is more important due to its close connection to learning.
Eye examination in Iran includes:
- accurate determination of visual acuity and refraction of the patient
- measurement of intraocular pressure
- analysis of the eye under a microscope (biomicroscopy)
- pachymetry (size of the thickness of the cornea)
- echobiometry (determination of the length of the eye),
- ultrasound examination of the eye (B-scan)
- computed keratotopography and a thorough examination of the retina (fundus of the eye) with a wide pupil,
- determination of the level of tear production
- detailed analysis of the patient’s field of view
If necessary, the scope of the survey can be expanded.
What is the process of eye examination in Iran?
Basic Eye Examination:
The examination begins by obtaining information about your state of health and family diseases. The doctor will most likely ask you to name the letters or numbers, shown in a table of letters and numbers arranged in rows and gradually decreasing in size. It allows your doctor to determine your central vision.
If you wear contact lenses, your eyesight will be tested at this point, the examination is done using a unique tool called a lensometer, and the doctor will check your glasses to confirm if the prescription was correct.
If the chart test shows that you need a prescription or contact lenses, the doctor measures the refractive error or focusing of the eyes with instruments that contain a set of contact lenses of varying strengths. To confirm your readings and find out which lenses provide the best vision, you will be given lenses of different strengths to test. The data gathered from studying natural and corrected visual acuity using a slit lamp should be evaluated according to the symbols of the Snellen chart. If the patient cannot distinguish capital letters, vision is assessed by determining the number of fingers. Then the patient’s perception of finger movements are evaluated and, finally, the ability to distinguish light from the darkness.
Determination of visual fields is carried out using a contrasting examination, with which the doctor can estimate the approximate degree of loss of visual fields.
Pupil Function Examination:
The study of the pupil’s reaction to light (indirect and involuntary) allows your doctor to assess the state of the optic tract. The absence of a direct light reflex is connected to unilateral damage to the optic nerve and occlusion of the central retinal artery.
A patient with glaucoma has an arcuate scotoma (an isolated area in which vision is weakened or absent along the nerve fibers and the optic disc edges). Central scotoma can be observed with optic neuritis. Bitemporal hemianopia / homonymous hemianopia (loss of the right or left halves of the visual fields) and quadrant hemianopia (loss of one quadrant of the visual field of one or both eyes) is observed in patients with neurological pathology.
Intraocular pressure is usually measured using a non-contact tonometer. If necessary, intraocular pressure measurement is carried out with Ocular tonometry. It is possible to conduct computer perimetry to exclude glaucoma in studying visual fields.
Before any surgical intervention and eye surgery in Iran, a refractive examination is performed, which includes:
The determination of visual acuity both without correction and optimal correction, biomicroscopy, ophthalmoscopy, tonometry, refractometry (using an auto refractometer), computer tomography of the cornea on a computer topograph, ultrasound biometry, and ultrasound pachymetry. The surgeon uses the data obtained during diagnostics when performing excimer laser correction.
Before refractive surgery in Iran, patients undergo pachymetry with a device for measuring the thickness of the cornea, which allows your doctor to calculate the maximum allowable depth of laser exposure, which in cases of a very high degree of myopia determines how much it is possible to precisely to carry out the correction.
A complete comprehensive computer diagnostic vision examination precedes any microsurgical or laser interventions. The analysis reveals the range of existing problems and determines the treatment tactics.
Any disease of the organs of the visual system requires a unique treatment approach, including at the diagnosis stage. Many ophthalmic diseases have similar symptoms, so even experienced professionals may not be able to make a diagnosis and even more so determine the degree of the disease without a thorough examination using specialized equipment. It is desirable to carry out diagnostics in a planned manner early. Below is a summary of the primary methods for diagnosing eye diseases.
Eye examination in Iran can be done with standard equipment such as an ophthalmoscope, but a more thorough examination requires special equipment and consulting with a qualified ophthalmologist.
Different Types of Eye Examinations in Iran for Different Eye Diseases:
Children and adults undergo different eye examinations depending on the kind of eye disorder they have, in order to determine which eye care they need. Eye Problems can be diagnosed during the following tests:
Anamnesis
Your medical history includes location, onset, rate of development, duration of current symptoms, the presence and nature of pain, discharge, redness of the eye, and change in visual acuity. In addition to vision loss and pain, warning signs may include flashes and floaters (both of which may indicate retinal detachment), double vision, and loss of peripheral vision.
Visual acuity
The first step in an ophthalmic examination of a patient is determining visual acuity. Allocating a sufficient time interval for the study and verbal encouragement of patients, as a rule, gives more accurate examination results. It is necessary to measure the patient’s visual acuity with and without glasses. A diaphragm with a hole can be used for the examination. In the absence of factory diaphragms for checking vision, one can easily be made by making several holes of varying diameters in a piece of cardboard using an 18-gauge needle. The patient needs to choose a spot that maximizes visual performance. The problem is a refractive error if visual acuity improves significantly when using a diaphragm. Using a diaphragm is a quick and effective way to diagnose refractive issues, the most common cause of blurred vision. The maximum correction achieved with a diaphragm is usually 20/30 (0.66 according to the Sivtsev-Golovin table), not 20/20.
To test visual acuity, it is necessary to cover the other eye with a dense object (it is better not to cover the eye with fingers, the density of which may change during testing). When examining vision, patients try to read a table at a distance of 6 m. If this study is not possible, it is possible to check the patient’s vision using printed text or a specialized table located 36 cm from the patient’s eyes. Normal vision or vision with deviations is calculated according to the conventional signs of Snellen. The Snellen index of 20/40 (6/12) indicates that the smallest letters that a person can read with normal vision at a distance of 12 m must be transferred to 6 m to be recognized by the patient. Visual acuity is determined by the tiniest lines in which the patient can read half of the letters, even if they seem blurry or have to be guessed from the outlines. If the patient cannot read the most extensive line in the table from a distance of 6 m, the test must be repeated at 3 m. If the patient cannot read the lines on the table even from the closest distance, the following test must be performed: the doctor holds a different number of fingers in front of the patient to see if he can accurately count them. If not, it is necessary to check whether the patient can perceive the movement of the hand. If not, then the light is sent to the eye to determine if the patient perceives the light.
Near visual acuity is tested using a standard table or newspaper at a distance of 36 cm. Patients > 40 years of age wearing glasses or contact lenses should wear them to try near visual acuity.
Refractive error can be roughly estimated using a handheld ophthalmoscope, choosing the lens necessary to focus the retinal image; to do this, you must use your lenses to test your vision. This procedure is not a substitute for a comprehensive refraction assessment. Most often, refractive errors are assessed using a standard phoropter or an automated refractometer (a device that measures changes in the reflection of light projected onto a patient’s retina). The same instruments help assess the degree of astigmatism.
Examination of the eyelids and conjunctiva
The rims of the eyelids and the tissues surrounding the orbit are examined under focused light under magnification (For example, with a loop, slit lamp, or ophthalmoscope). If dacryocystitis or canaliculitis is suspected, the lacrimal sac is palpated, and an attempt is made to squeeze out its contents through the lacrimal ducts and points. Eyelid eversion can examine the conjunctiva of the eyelids, globe, and conjunctival fornix for foreign body, signs of inflammation (e.g., follicular hypertrophy, exudate, hyperemia, edema), or other abnormalities.
Cornea examination
Fuzzy edges or blurring of the light reflex (reflections of light from the cornea) are a sign of a violation of the integrity or compaction of the cornea’s surface, for example, with corneal erosion or keratitis. Erosions and ulcers of the cornea can be detected using fluorescein staining. If the patient is in pain or if there is a need to touch the cornea or conjunctiva (for example, to remove a foreign body or measure IOP), local anesthesia with a solution of procaine 0.5% or tetracaine 0.5 may be used to facilitate the examination procedure for the patient. A sterile fluorescein test strip is moistened with a drop of sterile saline or local anesthetic and applied to the inside of the lower eyelid while the patient is looking up. The patient then blinks several times to spread the color over the tear film as the examination is performed under magnification in cobalt blue light. Areas lacking epithelium on the cornea or conjunctiva (in case of erosion or ulceration) are fluorescent red.
Viscometry
It is a type of eye examination through unique tables and trial lenses. Currently, they are being replaced by more modern projectors and phoropters. This study is subjective since it largely depends on the state of the examined organs of vision and the body. One of the varieties of viscometry is the selection of spectacle lenses.
Autorefractometry
It is the study of refraction and force of curvature of the eye’s cornea using an automatic refractokeratometer. This device allows the doctor to automate the process entirely. All that is required of the patient is to look at a unique mark, thereby keeping the head static.
Keratometry
It is the measurement of the curvature of the anterior surface of the cornea. This study calculates the optical power of an artificial lens and allows the doctor to detect and measure astigmatism. Previously, keratometry was performed manually using a ruler, but today a keratometer is used to conduct this study.
Tonometry
It is the measurement of intraocular pressure. It is used to diagnose glaucoma and optic nerve disorders. The tonometry technique is simple: first, drops are introduced into the patient’s eye to reduce the cornea’s sensitivity, and then an ophthalmic tonometer is applied to its surface. The device exerts a slight pressure on the cornea, and the result of the study is a reversed amount of resistance.
Pachymetry
It is the measurement of the thickness of the cornea at various points. The study is carried out using ultrasound. It serves to diagnose corneal dystrophy and is actively used before laser correction and to assess the condition of the eyes after corneal transplantation.
Biomicroscopy
It is the visual examination of the cornea, lens, iris, and other eye parts. This imaging method contrasts illuminated and unlit areas and allows the doctor to assess the state of the optical media, blood vessels, and optic nerves.
Ophthalmoscopy
It is the most common slit-lamp examination that examines the eyeball and adnexa of the eye. It is carried out to diagnose cornea, iris, lens, and vitreous body diseases.
What is the recommended frequency of eye examinations in Iran?
Generally, ophthalmologists recommend that people undergo a complete eye examination every one to three years, depending on their risk factors and physical health, for better eye care in Iran.
A comprehensive eye examination should be performed every two years for people aged 40 and older. Presbyopia, cataracts, and macular degeneration are age-related eye conditions that are more likely to occur as we get older. Eye examination in Iran is done through the newest technology with highly experienced doctors. To consult with the best doctors in high-quality clinics, don’t hesitate to contact CarefulTrip.
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