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Зміст© Pavlyuchenko K.P.
Specific objectives of teaching
Visual acuity tests (Landolt’s chart, Polyak’s optotypes)
Visual field testing (Ferster perimeter)
Visual field testing (confrontation test)
Investigation of Binocular vision
Examination of eyelids
Lagophthalmos (hare's eye)
Prolapse of the upper eyelid
Measuring intraocular pressure by palpation.
Clinical refraction measuring
Objective refraction assessment
Lacrimal apparatus examination
MINISTRY OF HEALTH OF UKRAINE
DONETSK M.GORKY NATIONAL MEDICAL UNIVERSITY
METHODICAL INSTRUCTIONS FOR STUDENTS OF MEDICAL
AND STOMATOLOGYCAL FACULTIES FOR MASTERING OF
PRAKTICAL SKILLS ON OPHTHALMOLOGY
Donetsk - 2012
Methodical instructions for students’ medical and stomatological faculties for mastering of practical skills on ophthalmology: methodical instructions / Pavlyuchenko K.P. et al. – Donetsk, 2012. - 18 p.
According to Higher Education Law of Ukraine, the priority of the state policy is to facilitate integration of Ukrainian higher school into the world educational system still preserving and developing national academic achievements and traditions. Decision of 24.04.2003 issued by the Ministry Board of the Ministry of Education and Science runs: “Introducing ECTS into the system of higher education of Ukraine is a key requirement under Bologna Declaration of 1999 and one of the prerequisites for entering Ukraine into Europe”.
The program to implement Bologna Declaration requirements has been approved by the Ministry of Education and Science resolution No 49 of 23.01.2004. The Methodical instructions have been made according to ECTS conversion plan for medical and stomatological faculties’ students for mastering of practical skills on ophthalmology. It is an instructive textbook on practical skills for students of III-IV accreditation level medical universities.
The Methodical instructions were approved for publishing by the Academic Board of Donetsk M. Gorky National Medical University on 22.03.2012, the report No3.
1. Sukhina L.A., MD, Professor, Head of ocular diseases department, post-qualifying education medical faculty Donetsk M. Gorky National Medical University.
2. Basiy R.V., PHD, Associate Professor of human anatomy department, the Coordinator of the educational and methodical department Donetsk M. Gorky National Medical University.
Donetsk M. Gorky National Medical University 2012
These methodical instructions for students’ medical and stomatological faculties for mastering of practical skills on ophthalmology studies on the module «Ophthalmology». Purpose of study of ophthalmology - ultimate goals is determined on the basis of educational professional program, teaching of student on specialist. Thus the question is not only about theoretical knowledges but also practical skills. As, for example: to use ethics principles for an examination and treatment of patients; to determine the etiologic factors of development of eye diseases; to identify, in objective examination the symptoms of central and peripheral vision disorders; to interpret the findings obtained in visual function examination with the purpose of determining the damage pattern of the eye, basic visual pathways and cortex centers; to determine a preliminary diagnosis. It is also necessary to be able to conduct a differential diagnosis with similar diseases and determine tactic of treatment of patient. Control of mastering of practical skills is conducted on every topic. The list of skills corresponds a necessity, at the 1st stages of module control. Mastering of practical skills is checked up by a teacher in an educational room in presence the students of all group. Skills are demonstrated students of one another or on thematic patients. There is necessary equipment (Landolt chart, Polyak optotypes, biomicroscope, Ferster perimeter, pseudoisochromatic Rabkin table, lamp, Maklakov tonometer, mirror ophthalmoscope, spherical lens 13D, filter paper strips, a box contains test frames and spherical test lenses, sciascopy device, Worth’s four-dot device)
and materials in an educational room (bandages, cotton wool, Furacillin, 2% Collargol, 1% Tropikamid).
Creation of these methodical instructions is caused the necessity of upgrading of mastering of practical skills students that is one of important sections of ultimate goal of teaching of discipline.
1. Color vision test by the E.B. Rabkin’s tables…………………… .... 7
2. Visual acuity tests (Landolt’s chart, Polyak’s optotypes)……… … 8
3. Visual field testing (Ferster perimeter)…………………………… ...9
4. Visual field testing (confrontation test)…………………………… 10
5. Investigation of Binocular vision (Worth’s four dot test)……… ….10
6. Focal illumination………………………………………………….……11
7. Transmitted light examination……………………………………….. 11
8. Examination of eyelid…………………………………………………..12
9. Measuring intraocular pressure by palpation……………………….14
10. Clinical refraction measuring ………………………………………..14
11. Hirschberg test………………………………………………………….15
12. Lacrimal apparatus examination…………………………………….16
13. Principles for prescribing spectacles……………………………….17
The presented practical skills are actual for a future doctor. So, violations of visual functions, which come to light during their research, help in diagnostics of row of internal illnesses, knowledge of reasons of pathology of visual functions, in a number of cases can help to warn development of disease. Ability to inspect the organ of sight is needed in diagnostics of nervous diseases, pathology of liver, avitaminosises, of infectious diseases, parasitoids’.
Ability to examine eyelids, it is necessary in diagnostics of infectious, neurological, parasitogenic diseases. Research of reaction of pupil on light, determination of mobility of eyeballs very important at diagnostics of neurological and neurosurgical diseases.
Picture of retinal image needs the doctors for understanding of picture of eye fundus, described during consultation of ophthalmologist. The doctor of domestic medicine must be not only used ophthalmoscopy but also distinguish pathology from a norm.
Very important are skills, necessary for diagnostics of glaucoma, urgent pathologies of eye and cataract, in connection with their prevalence and possibility of development of irreversible blindness, included in the list of addition the «Urgent states» of Educationally qualifying description
Ocular trauma is one of the actual problem of the modern ophthalmology in connection with its prevalence in industry, agriculture, domestic, among adults and children, and very actual as the urgent state, requiring the special attention. Authors hope that the methodical instructions will help students in mastering of ophthalmology practical skills and to use them in future practical activity.
to be able:
to choose from complaints, anamnesis information, reflecting pathology of organ of sight; to make the individual chart of diagnostic search; to conduct necessary researches of functions and state of structures of eye and appendages; to interpret the got results; to put a preliminary diagnosis and conduct differential diagnostics with similar pathology; to define tactic of treatment of patient.
to be able:
Choose the data reflecting visual function disorders from a set of complaints, medical history.
Identify, in objective examination the symptoms of central and peripheral vision disorders.
Identify the signs of color perception in objective examination. Interpret the findings obtained in visual function examination with the purpose of determining the damage pattern of the eye, basic visual pathways and cortex centers.
Examine conjunctiva, cornea, anterior eye chamber and iris with focal illumination.
Examine the lens and vitreous body with transmitted light. Examine tear secretion and tear drainage process.
Identify the most informative signs of abnormalities obtained in the patient objective examination.
Estimate of intraocular pressure by palpating the eyeball. Investigate binocular vision, refraction and strabismus angle and interpret the examination.
Make a preliminary and differential diagnosis, and treatment plan.
Color vision test by the E.B. Rabkin’s tables
The pseudoisochromatic plates include a mosaic of colored elements in which numbers or other figures are printed in critical colors. The examinee is allowed to watch the plate for a moment. Duration of display of every table - 3-5 seconds, but no more than 10 seconds. The examinee sits the back to the illumination. They have to describe the figure they see from 1m distance. A person with color vision defect reeds a wrong figure or cannot see any figure at all. To interpret color perception disorders it is essential to know that dyschromasia (a congenital color vision disorder) is characterized by various intensity and behavior. A person perceiving all three colors is called trichromatic, he who is able to perceive two colors is called dichromatic and a perceiver of one color is called monochromatic. The highest degree of defected color perception is monochromatism that features the absence of components differentiating light wavelengths. In this visual defect, objects of various colors appear as variations of a gray color (white to black). With monochromatism the vision is always very bad as retina cones are affected.
Dichromatism is of three types: protanopia, when the red component is lost; deuteranopia, when the green component is lost, tritanopia, when the violet component is lost. Dichromatism prevails in males.
There are people with weak color perception. This phenomenon is called anomalous trichromatic.
Visual acuity evaluation is needed for central vision quantitative estimation. It is performed 5m away from a patient in a dark room with a visual acuity Landolt’s chart. The eyes are examined separately; the other eye is covered with a non-transparent shield. The patient is shown lines of rings in succession from bigger to smaller ones. A patient must determine direction of cuts in rings. Patient’s visual acuity is determined by the smallest perceptible ring’s cut. Knowing the distance from the chart and the distance of normal visual acuity for the line perceived, one can easily determine the patient’s visual acuity by Snellen equation , where V - Visus – visual acuity, d – testing distance and D – the distance on which the optotypes fulfills the demand of 1’ visual angle. Normal visual acuity is identified with 1,0 and corresponds to the 10th line at a 5m distance.
Patients with low visual acuity unable to recognize even the ring’s cut from first line are shown the Polyak’s optotypes or offered to recognize the number of the tester fingers shown against a dark background. In this case, visual acuity is calculated accordingly. Patient’s visual acuity is evaluated as 0,02 if he can count fingers only from 1m distance or 0,01 if he can see its from a 0.5m distance and V = count fingers if distance less then 0.5m (it’s minimum uniform sight).
Polyak’s optotypes is a collection of figures corresponding to different visual acuities (from 0.09 to 0.01). The visual acuity is determined within 0,01.
When formal vision is absent, the light perception and projection ability are evaluated. In a dark room, a source of light is located behind and to the left of the patient. Ophthalmoscope mirror directs the light beam into the patient’s eye from different points. The patient has to say if he can see the light and where from. Such vision is identified as proectio lucis certa, i.e. light perception with right light projection. Light perception with wrong light projection is identified as proectio lucis incerta. If the patient is not able to discriminate between light and dark, his visual acuity equals 0.
To evaluate peripheral vision it is essential to quantify the visual field embraced, with the eyes, head and a certain point fixed.
Each of the eyes has its own limits of visual field. The limits correspond to the limits of optically active retina and are bounded by protruding parts of the face: Nose Bridge, eye socket upper edge, cheeks. Normal visual field borders from the central point of fixation are: 90 outwards, 70 up and outwards, 50-55 upwards, 60 up and inwards, 55 inwards, 50 down inwards, 65-70downwards, 90 down outwards. Individual deviations within 5-10 are possible. Accurate evaluation of visual field can be done by projecting field limits on a spherical surface. Visual field examination performed on a desk perimeter or all-purpose projection perimeter is called perimetry. For Ferster perimeter examination, the patient seated in front of the instrument looks at the white fixation point in the centre of perimeter arc. The examiner stands at the perimeter side and moves a white object along the arc (periphery to centre). The patient has to catch the moment when the moving object appears. Tests are repeated every 15 at the meridians.
During testing, marks results on a chart. The object dimensions are chosen within 3-10mm according to the patient vision acuity.
Visual field deviations appear as missing areas (scotoma). Campimetric techniques are advisable for accurate examinations. The patient is seated 1m away from a 2x2m black board (campimeter). A white symbol in the centre of the board is a fixation point. For testing, a white-color object (1-3mm circle) is used. The circle is moved along horizontal line intersecting the fixation point in the outside half of the visual field from periphery to the centre or vice versa. The moment when the object disappears is recorded. Then visual field limits are evaluated vertically. Eyes are tested separately.
There is a finger technique, the simplest but not very accurate, only efficient for gross lesions of visual field. Patient and physician are seated 5m away facing each other so that the light is behind the patient. The patient closes his right eye while the physician closes his left eye, and vise versa when the right eye is examined. It is important that the examiner should have normal limits of visual field. The examiner does some minor movements with his fingers or hand along the center line between him and the patient gradually nearing the visual filed center. The patient has to spot the moment when the doctor’s hand appears in his visual field. If he catches the moment simultaneously with the doctor, it means that his visual filed has normal borders in this direction. Similarly it is repeated at 4-8 meridians. Thus it is possible to evaluate the limits of visual field.
(Worth’s four dot test)
Binocular vision can be tested by colored lights or figures, which the patient is looking at through spectacles which filter away the corresponding wavelength. In Worth’s four dot test a red lens is in front of the right eye and a green lens is in front of the left eye. There are four dots on the screen: the upper one is red, the two at the sides are green and the one at the bottom is white. The patient sees the red light and the white light through the red lens and the three green lights through the green lens. A person with normal binocular vision is able to combine the stimuli from the right and the left eye and thus the four lights are perceived simultaneously. A patient with monocular vision sees three green lights or two red one.
The method of focal illumination is examination of the conjunctiva of eyelids and eyeball, sclera, cornea, anterior chamber, iris, pupil and anterior lens surface Examination is performed in a dark room with an electric lamp. The patient sits on the left of the table; the lamp is 40-60cm away on his left and a little in front of him at his eye level. The patient’s face is illuminated from the side and the front. Ophthalmologic kit is available for examinations. It includes two magnifying glasses (lenses) of 13 and 20 diopters and a mirror ophthalmoscope. A bundle of light beams is directed from the lamp with the help of one of the lenses, which is held with the right-hand thumb and index finger. To obtain the brightest illumination the lens should be at a distance of its principal focus from the eye, i.e. 8cm and 5cm respectively. The examination should be performed at the largest possible angle to the beams directed into the eyes. Illuminated area is well seen against the shadowed areas.
^ In this examination, the ophthalmologist holds the second lens of the kit in his left hand sets it at the focal distance from the patient’s eye and examines a magnified image of the anterior eye part.
Transmitted light examination
Transmitted light examination is performed in a dark room. The source of light (60-100W matted electric bulb) is placed a little behind the patient on his left. The examiner sitting in front of the patient sets the mirror ophthalmoscope against the patient’s right eye moves it 20-30cm to the patient and directs the reflected light into the pupil to investigate the eye through the ophthalmoscope aperture. If the light beam meets no obstruction in the passage to the eye fundus, the pupil shines red. The light reflected from the choroid vessels explains the red color. Focal opacities in the eye optical medium retain the light beam and are visible as dark spots against the red background of the pupil. Cornea opacity is easily detected in external examination and focal illumination.
Lens opacities shift with the eye movement and they are compact. Motility is common with the vitreous body opacity. In the eye fixed still after some voluntary movements the vitreous body opacity keeps moving while the lens opacity comes to a stop. Opacity located in the pupil plane shifts in the direction of the eye movement. Opacity moves in the opposite direction to the eye movement if located behind the pupil plane. When lens opacity is complete and vitreous body is filled with blood or exudate, the pupil does not shine in transmitted light.
Less red reflex is visible with a small pupil, limiting the usefulness of this test.
Before studying eyelids under magnification, a general external examination and focal illumination is performed.
The general appearance, position and motility of the eyelids and the position of lid margins in relation to the eye are noted. The palpebral fissure is normally symmetrical and varies from 9 to 13 mm in height. The normal upper lid margin covers the limbus by 1 to 2 mm.
^ is a complete or incomplete opening of the eyelids when the anterior section of the eye globe remains open and unprotected by the eyelids. It can be caused by mechanical factor - a sudden exophthalmos. Other causes include peripheral nucleus basalis or radicular paralysis of the facial nerve branches innervating the orbicular muscle of eye. Such paralyses occur with otitis, mastoiditis and systemic infections. Peripheral lagophthalmos is complicated with excessive tear production, conjunctivitis, pains in the ear or eye region, hearing impairment, cornea dryness and keratitis.
Primary task in lagophthalmos treatment is to eliminate the cause. Ointment dressings should be used to protect the cornea from drying. With irreducible paralysis and keratitis the eyelid suturing is necessary.
^ (ptosis) can be congenital or acquired. The causes are various: inflammatory infiltration of the conjunctiva anterior fornix, cartilage and muscles raising the upper lid as in trachoma; a traumatic inflammatory process in the Muller’s muscle and left upper lid levator palpebrae superiors muscle; an infectious inflammatory process leading to paralysis of the oculomotor nerve (diphtheria, rheumatism, meningitis).
Ptosis may be cortical, subcortical, nucleus, fascicular and brainstem. Treatment should be aimed at the basic underlying disease. When the drooping lid covers pupillary area of the cornea, surgical treatment is administered.
^ is a reflectory tonic spasm of the orbicular muscle of eyelids. It is commonly related to trigeminal nerve irritation in traumas or inflammatory diseases of eyelids, conjunctiva, and cornea.
Eyelid entropion is a condition in which the lid turns inward to the eyeball and lashes cause much irritation by rubbing on the cornea like a brush and damaging it.
Entropion may be spasmodic due to contraction in the palpebral part of the eye orbicular muscle or scary due to cartilage deviation or shortening of posterior conjunctival surface of the eyelid, commonly after severe burns. Spasmodic lower lid entropion occurs in elderly people with slack skin in keratitis or conjunctivitis. It can also develop in younger people suffering severe blepharospasm caused by cornea diseases. Light entropion can be corrected with a plaster applied to the retracted eyelid. In severe cases, surgical treatment is necessary.
Eyelid ectropion is a condition in which the lower lid falls away from the globe. In severe cases, posterior conjunctival surface is exposed and turned outwards. Conjunctiva is badly hypertrophied and hardens due to constant conjunctiva irritation, which is often followed by excessive tearing due to drainage failure. Spasmodic ectropion develops in chronic blepharoconjunctivitis. Paralytic ectropion is found with facial nerve paralysis. Atonic ectropion is common in elderly people. Ectropion requires surgical treatment as a rule.
Intraocular pressure may be normal, elevated (with glaucoma and ocular hypertension) or reduced (ocular hypotension). Palpation is an approximate evaluation of intraocular pressure. A patient is asked to look down while the examiner gently presses the eye over the upper lid cartilage with the both index fingers by turns. The fingertips feel rigidity of the eyeball. The higher the pressure, the more rigid the eye is. With low pressure, the ball is soft and flexible. Normal pressure is marked with Tn. There are 3 degrees of elevated intraocular pressure in palpation: Т+1 – moderate elevation of the eye tone; Т+2 – marked elevation, Т+3 –severe elevation; and 3 degrees of reduction, respectively Т-1, Т-2 and Т-3. Palpation method is useful for determining intraocular pressure when tonometry is contraindicated (corneal ulcer, keratitis). In this procedure, the tone of one eye is compared with the other.
Accurate intraocular pressure can be determined by using Maklakov tonometer.
All the methods used for refraction assessing can be divided into objective and subjective.
Subjective method involves adjustment of corrective glasses with visual acuity monitoring (vision without glass correction is called relative; with glass correction is called absolute).
At first, visual acuity is assessed. Then convex or concave glasses (+0,5 D or –0,5 D) are tried at each eye separately. In emmetropic patients, convex glasses cause deterioration, and concave glasses do not improve vision. In myopic patients, visual acuity improves with concave glasses; in hypermetropic patients, it improves with convex glasses. Then, gradually increasing the glass power it is possible to choose a glass that enables to fully improve the visual acuity and is comfortable for the wearer. This glass determines clinical refraction.
Quite often, a patient is able to name letters of subsequent line but unable to name the previous line of letters, or he tries to change the position of his head. Then astigmatism is suspected. The best absolute visual acuity can not be achieved only with spherical lens; correction with cylindrical glass is required.
^ includes sciascopy and refractometry.
Refractometry, which is increasingly used for assessing clinical refraction, is another objective procedure. The patient is sitting in front of refractometer; special refractometer-installed markers are projected in his eye. While moving the markers, the best marker image is achieved and the clinical refraction ant its degree is determined on a special scale or automatically (in automatic refractometer). Objective assessing of astigmatism meridians and degrees is also available.
Ophthalmometry determines refracting power and the curvature radius of the cornea.
Strabismus may be unilateral and bilateral (alternating), in which eyes decline alternately. According to declining direction, strabismus may be inward and outward as well as upward and downward.
The amount of declination (strabismus angle) is expressed in degrees and determined with various procedures. The simplest one is Hirschberg method. In this test the symmetry and size of deviation of the reflected light spots on the cornea is observed. The patient is asked to fix his gaze on the ophthalmoscope. Light beam from ophthalmoscope coincides with the pupil center on the cornea in the unaffected eye. Corneal reflection in the other eye is displaced. Strabismus angle is 15º, if, with an average pupil width (3-3.5mm), the corneal reflection of light is located at the pupil edge; 25-30º, if it is between the pupil edge and the limb; 45º, if it is at the limb; 60º and over, if it is behind the limb.
It is necessary to distinguish real strabismus from imaginary one. At the last, light reflex also will not correspond the center of pupil. The simplest method of diagnosis is determination of binocular vision on four dot device. At a real strabismus binocular vision always absents.
Includes assessing the lacrimal openings size and relative position against the lacrimal lake. Pressing the lacrimal sac region enables to detect discharge of abnormal contents from lacrimal ducts and sac through the openings. Palpebral part of the lacrimal gland can be examined when the upper eyelid is lifted up and outwards and the patient is asked to look at his nose tip.
^ is the assessment criterion for tear production. A filter paper strip of 1x5cm is placed behind the lower eyelid. The free end of the strip lies outside on the lid skin. With normal tear production the paper will get soaked in 5 min as far as 15-18mm from the lid edge. Less than 15mm soaking indicates reduced tear production.
^ is used to examine the functioning of lacrimal canaliculi. After placing 1-2 drops of 2% collargol solution behind the lower lid the patient is required to do several frequent winks. Originally collargol paints the scleral conjunctiva in a brown color. If lacrimal punctum openings and duct function normally, collargol disappears from conjunctival sac in 0.5-2 min, which can be recognized by whitening of the eyeball. Then the test is positive. With negative test the eyeball is colored brown for a long time.
^ helps detect any obstructions of the nasolacrimal duct. Emergence of collargol in the nose (a light blow from the nose on a small piece of cotton wad) 5 minutes after 1-2 drops of the 2% solution have been placed in the conjunctival sac indicates that the passage is not blocked. If it takes more than 10 minutes for collargol to appear in the nose, there is some obstruction in the passage. If collargol does not emerge even 30 minutes later, the obstruction is complete.
Irrigation of lacrimal drainage system enables to determine passive anatomic obstruction. For irrigation a 2-ml syringe with a blunt and not very thin needle is used. Sterile solution is used. At first, a lacrimal opening is dilated with a cone-shaped probe, and then the syringe needle is inserted 5-6mm deep into the lacrimal duct. Saline is injected slowly. With no obstruction in the duct solution trickles out through the nose.
Nasolacrimal duct obstruction is the most common obstructive lacrimal disorder. Patients are typically infants (congenital nasolacrimal duct stenosis) or elderly with involutional degeneration of ductal tissues and stenosis.
Glass correction for distant vision usually corresponds with ametropia degrees. For instance, the myopic sufferer with -3,0D in both eyes wears distant spectacles with -3,0D spherical diverging glasses. Hypermetropic eyes with +3,0D need converging +3,0D glasses. If ametropia glass correction is subjectively intolerable (dizziness, nausea, discomfort), more tolerable (lighter) adjustment should be made. When refraction between the right and left eyes differs significantly, unequal corrective glasses should be prescribed. As a rule, difference of the optic power of the glasses should be under 2,0D-3,0D. For instance, ОD – sph –1,0 D; OS – sph - +2,0 D; ОD – sph +3,0 D; OS – sph - +5,0 D. Bigger difference causes discomfort and deterioration of binocular vision. Adjustment for reading glasses involves distant correction, if any.
Age-related changes in accommodation are called presbyopia, or senile vision. Presbyopia appears when the shift of the near point of clear vision is more than 30-33 cm and the ability to read or work with close-up objects is lost, which usually happens in the 40s age group. Actually, accommodation weakens slightly (about 0.001D) every day. The treatment includes corrective eyeglasses for close-up viewing tasks. The power of eyeglasses to be prescribed depends on the patient’s refraction, age, and the task distance.
Close viewing glass according to the patient’s age is added: at 40 - converging glass +1,0 D; at 45 +1,5 D; at 50 +2,0 D; at 55 +2,5 D; at 60 +3,0 D, that is adding +0,5D every 5 years. For instance, the patient uses - 0,5 D for distant correction. At the age of 40, he needs for close viewing tasks +0,5 D (-0,5 D + +1,0 D = +0,5 D), while a 60-year-old myopic patient with 3,0 D needs no reading spectacles as –3,0 D + +3,0 D=0.
Accommodation spasm manifests itself with deterioration of the visual acuity that improves with diverging glasses. Besides, the pupil narrows, the near point of clear vision approaches the eye, temporary accommodation spasm occurs after instillation of contracting agents (i.e. pilocarpine) with long-term accommodation in people with different refraction, particularly in hypermetropic under unfavorable conditions and general weakness. A so-called false myopia develops.
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