Examination of Eye

Examination of Anterior Segment Examination of Posterior Segment

Examination of Anterior Segment of Eye Examination of Vision Assessment of visual function Forms of visual perception are form sense , the field of vision, the light sense and the colour sense, these senses are checked with

Examination of Eye Visual Acuity Visual field examination with confrontation test, perimetry (kinetic and static) Dark adaptation – measurement of least luminance required to produce a visual sensation Contrast sensitivity – is measurement of the smallest distinguishable contrast ,it is assessment of quality of vision Colour vision –with lantern test (Edridge green lantern) and Isochromatic charts

Visual Acuity Definition- It is defined as the measure of the smallest retinal image which can be appreciated with reference to its shape and size .it is actually measure of form sense. Subjective examination of the function of eye Central or direct vision Distance vision with Snellen test type Near vision with Snellen test type or Jaeger’s test type

Visual Acuity The principal of assessment is measurement of spatial resolution of the eye i.e. an estimation of ability of eye to discriminate between two points. DISTANCE VISION Two distance point can be visible as separate only when they subtend an angle of 1 minute at the nodal point of eye.

Snellen chart Principle Each individual letter subtends an angle of 5 minutes and each component of letter subtends an angle of 1 minute at the nodal point of eye from the distance in meters written as numerical. Snellen chart is having different number of letters in different rows and the letter at top line should be read clearly at distance of 60 m. similarly the letters at subsequent lines as are read at 36, 24,18,12,9,6,5mts respectively

Snellen Chart

Snellen Chart

Trial Frame

Occluder and Pin Hole

Snellen chart Numerical convention is used for recording visual acuity. In fraction, the numerator is the distance at which the patient is sitting from chart and the denominator is the distance at which person (with normal vision) should be able to read the last line that person is able to read.

Procedure of testing Patient is seated at the distance of 6 meters from Snellen’s chart (distance of 6 mts is taken as at this distance it is assumed that the rays are almost parallel and patient exert minimum accommodation) The chart should be properly illuminated at minimum of 20 feet candles. Patient made to wear trial frame. It is adjusted according to patient inter pupillary distance.

Procedure of testing Ask the patient to read with one eye from the top letter while the contra lateral eye is closed gently with the patient arm or with occulder in the trial frame. Now patient is asked to reads the Snellen’s chart and depending upon the smallest line which the patient can read from distance of 6mts his vision is recorded as 6/6, 6/9 ,6/12,6/18, 6/24, 6/36, 6/60. But if patient is not able to see the top line from 6mts he is asked to come towards Snellen’s charts step by step and vision recorded at 5,4, 3, 2, 1 mts and noted as 5/60,4/60,3/60,2/60,1/60 respectively

Occluder

Procedure of testing If patient is not able to read top line even at the distance of 1 mts he is asked to count fingers of examiner and his vision is recorded as CF3FT, CF 2FT, CF1FT OR CF close to face . If patient not able to count examiner finger close to face then examiner waves or moves his hand and asks patient whether he is able to see hand movement or not. Visual acuity then recorded as HM+

Procedure of testing When patient cannot distinguish hand movements the examiner notes whether the patient can perceive light (PL) or not. If he perceive light it is noted as PL +ve otherwise as PL-ve. Also examiner then throw the light from four directions (nasal, superior, temporal, inferior) and record accordingly. if present patient perceive light from all directions it is marked as PR (Projection of rays ) present or else mark as absent or defective. The test is repeated for the other eye in similar fashion

Procedure of testing English chart Landolt ring chart This is the chart containing a series of broken rings, with each gap subtending an angle of 1 minute at nodal point at a given distance. It is used in illiterate patients. E-chart – used in illiterate patients Simple picture charts for children.

Procedure of testing Method Pin hole test Method After noting vision unaided patient is asked to read Snellen’s chart while holding a pin hole (hole size is 1mm) exactly in centre of pupil in front of eye. Now patient’s vision is noted and similar pin hole vision is recorded for other eye also

Pin Hole

Pin Hole Test Interpretation If patient vision is improved with pin hole it means the poor acuity is due to refractive error. If static acuity means may be due to structural or organic cause. If reduced the poor visual acuity may be due to corneal opacity or lenticular opacity occupying papillary area or macular pathology.  

Near vision Charts for testing near vision are 1) Snellen near vision chart - 2) Jaeger chart 3) Roman test type

Method of recording Near vision Ask the patient to sit with his back to the light If the patient is using glasses for distance the same number will be put on the trial frame. Occlude one eye with an occulder Ask the patient to hold the near vision by his right hand at a distance of 25 to 33 cms. Note the near vision as per the letter read Repeat the test for the other eye.

Examination of head posture Position of head, face and chin should be noted. Note for elevation/depression of chin Note for any elevation or depression of head Face turn to right or left In complete Ptosis (chin is elevated to uncover the papillary area in a bid to see clearly) In paralytic squint (head is turned in direction of action of paralyzed muscle to avoid diplopia).

Blepharophimosis Syndromen note chin elevation

Examination of forehead Look for increased wrinkling (due to over action of frontalis muscle) in patient with Ptosis. Complete loss of wrinkling in one half of the forehead is observed in patient with lower motor neuron type of facial palsy (seventh nerve palsy). Facial asymmetry may be noted in patient with bell’s palsy, musculo-facial anomalies and facial hemiatrophy.

Examination of eye brows Level of the two eyebrows may be changed in a patient with Ptosis (due to over action of frontalis) Madarosis -Cilia of lateral one third of eyebrows may be absent in patient with leprosy and Myxoedema. Scarring in and area around eyebrow should be noted

Examination of the eyeball Observe the following points Position – normally the two eyeball are symmetrically placed in the orbit in such a way that a line joining the center point of superior and inferior orbital margins just touches the cornea

Examination of the eyeball a) Abnormality of the position eyeball can be – Proptosis /exophthalmos – buldge of the eyeballs –note whether proptosis is –axial or eccentric Reducible or non reducible Pulsatile or non pulsatile Enophthalmos – (sunken eyeball) Absence of eye ball (clinical) is called Anophthalmos.

Proptosis

Shrunken (small) eye ball

Sunken Eye Ball

Examination of the eyeball b) Visual axis of eyeball Normally the visual axis of the eyeball is simultaneously directed at same object which is maintained in all the directions of gaze. Deviation is the visual axis of one eye is called squint.

Examination of the eyeball c) Size of eyeball Measurement of eye is made by ultrasonography (A-scan) Size of eyeball is increased in conditions like buphthalmos and unilateral high myopia.  Size of small sizes eyeball are-congenital Microphthalmos, phthisis bulbi and atrophic bulbi

Examination of the eyeball d) Movement of eye ball The movement are tested uniocular (duction)as well as binocularly (versions) in all the six cardinal directions of gaze. Uniocular – Adduction, abduction, depression, elevation, depression and elevation in adduction and abduction Binocular

Examination of the eyeball Binocular Ocular Movements 3 3 4 5 4 5 1 2 1 2 6 7 8 6 7 8 Right side Left side 1 = Dextroversion; 2 = Levoversion; 3 = Elevation; 4 = Dextroelevation ; 5= Levoelevation; 6= Dextrodepression; 7= Depression; 8 = Levodepression