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الكلية كلية الطب
القسم الجراحة
المرحلة 5
أستاذ المادة اسعد جعفر عبد السادة الطائي
4/20/2011 8:05:35 PM
9) conjuctiva:
-bulbar conjuctiva: look for congestion, pingaecula, pterygium, naevus, subconjuctival haemorrhage and oedema.
-palpebral conjuctiva: you need to evert the uppr lid, look for evidence of congestion, follicles, papillae, growth, membrane or pseudo-membrane.
examination of the upper fornix is done by double eversion of the upper lid using a lid retractor. the lower fornix is easily inspected by gently pulling the lower lid down.
10) sclera:
look for any localized or generalized coloration, localized or diffuse congestion or oedema, nodule, ectasia (a localized outward protrusion), or staphyloma (an ectasia containing uveal tissue).
11) cornea:
needs high magnification for adequate examination. look for: size, shape, curvature, sensibility (cotton-wool wisp), opacity, oedema, vessels or foreign body. abrasions and epithelial lesions can be detected by the use of a vital stain (e.g: sodium fluorescein or rose bengal).
12) anterior chamber (a.c):
average axial depth is 3mm. it is shallow in (genetically determined normal shallow a.c , primary angle closure glaucoma and lens intumescence). deep a.c is seen in (aphakia, buphthalmos and total posterior synechia). the normal content is the colorless aqueous humor. abnormal contents may be blood (hyphaema), pus (hypopyon), lens matter or a foreign body. reaction in the a.c may be cells seen in the beam of slit-lamp (tyndall phenomenon) or proteins obscuring the view of iris (flare) seen in uveitis.
13) iris:
a muddy colour is seen in iritis. if the pupil is adherent to the lens we call it (posterior synechia) making the pupil irregular and festooned on dilatation . anterior synechia is adhesion of iris to cornea, which if was peripheral we call it (peripheral anterior synechia- pas) it can cause resistant secondary glaucoma due to occulsion of the angle of the ac. iris may show tremulousness (iridodonesis) on movement of the eye e.g : in aphakia it may locally undergo disinsertion causing an almond shaped peripheral opening (iridodialysis). polycoria (multiple pupils), corectopia (ectopic pupil), aniridia and coloboma are congenital in origin.
14) pupil:
check size, site, reactions (direct, consensual and near response) comparing with the other side. abnormally small pupil (miosis) is seen in : iritis, miotic drugs (e.g : pilocarpine eye dropings) and sympathetic palsy (horner s syndrome). abnormally large pupil (mydriasis) is seen in : optic atrophy, mydriatic drugs e.g : atropine and oculomotor nerve palsy.
15) lens:
needs slit-lamp biomicroscope and/or direct ophthalmoscope for its examination. you may find : cataract, subluxation (lens equator is partially visible in the pupil) or dislocation (anterior in : a.c) or posterior (in the vitreous).
16) ocular tension:
there are three main methods for estimation of ocular tension (i.e intra-ocular pressure):
1- digital (bi-finger) tonometry: least accurate.
2- indentation tonometry e.g: by schi?tz tonometer, this is of better accuracy, can be used on diseased cornea or lying down patients.
3- applanation tonometry e.g: by goldmann tonometer, most accurate but needs slit-lamp biomicroscope so the patient must sit on a stool and cooperate.
subjective examinations of the eye:
-visual acuity:
for distant vision: we use snellen s chart placed at a distance of 6 meters. letters are of graduated size and each letter subtends an angle of 5 minutes at the nodal point of the eye when viewed from its specified distance. illetrate (e) chart and landolt (broken c) chart are modifications serving legibility and standardization. the patient should be able to appreciate the shape of letters, that is why visual acuity is a test for (form vision) which is a function of cones concentrated in the foveola. it is obvious therefore that the patient should be conscious, orientated and mentally normal.
for near vision: we use a near vision chart held at the ordinary reading distance (roughly 30cm), or a newspaper.
-colour vision:
again a cone function (visual acuity + colour vision is called day vision because both need high level of background illumination). tested by pseudo-isochromatic plates consisting of multi-coloured dots outlining certain digits e.g: ishihara.
the most common anomalies of colour-vision are various types of red-green colour blindness inherited as x-linked recessive conditions which occur in about 4.5% of males in iraq and arabian peninsula. acquired defects of colour vision occur in macular and optic nerve disease.
-visual field:
it is all the stimuli in the visual environment that can excite retinal elements of an eye in a moment of time. it is limited by retinal extension and margins of the orbit, nose and cheek. the method used to estimate the visual field is called perimetry. there are 4 types of perimetries:
1- confrontation tests: compare the patient s visual field with that of the examiner. here you don t need a perimeter. simplest and can be uniocular or binocular.
2- perimetry using a perimeter:
a perimeter is an instrument to plot the visual field. perimeters are of 2 types:
a) arc perimeters: simple, cheap, useful but old and less precise, consist of a movable arc along which the stimulus may be moved.
b) bowl perimeters: the eye is in the center of a hemispherical illuminated bowl upon which spots of light of various intensities, sizes or colours may be projected or moved in order to detect limits of the field and its sensitivity in various parts. these are of 2 types:
i- goldmann s perimeter: test conditions and the intensity of the target are always the same whenever the patient is tested. this permits greater reproducibility and standardization of the results.
ii- automated perimeters: computerized and the target do not move (static perimetry).
3- campimetry:
tangent screen (bjerrum s screen) a square piece of black cloth 1 or 2 meter sided. it tests the central 30 degrees of visual field only that is why it helps delineate central or paracentral scotomas found by perimetry and magnifies them.
4- amsler s grid: a 10cm sided square grid into 400 (5mm sided) squares chart. when the chart is viewed at 1/3rd of a meter each square subtends an angle of 1ْ.
the patient is asked to look at the centre of the chart and see if any of the squares are missing or if lines appear misshaped. the test is extremely useful for screening as well as the the follow up checking of the clinical course of macular lesions such as age related macular degeneration. it is done by the patient at home on doctor’s instructions.
types of visual field defects:
a- contraction: 1) concetric.
2) local: i- sector hemianopia and quadrantanopia.
ii- irregular.
b- island defect: called scotoma e.g: central, centrocaecal, arcuate.
c- enlarged blind spot.
the visual field defect may be absolute (no perception of light) or relative (only to certain colours), and a scotoma may be positive (a black or coloured shadow infront of vision – due to media opacities) or negative (a patch of transparently absent vision – due to pathway lesions).
instruments used in ophthalmological examination:
for ophthalmological examination we need:
1) illumination. 2) magnification.
illumination could be:
a- diffuse light: not focused on the eye e.g : day-light or diffuse room-light.
b- focal illumination : focused on the eye e.g : torch, projector, etc.
magnification : a high-power biconvex lens is usually used and it is called (loupe). it is of two types:
a- hand held loupe: one lens with a suitable frame.
b- binocular loupe: in spectacles or head-belt, maintains stereoscopy and can be used by surgeons to conduct surgery.
in ophthalmological instruments we combine illumination and magnification together with other desirable capabalities for eye-manouvering allowed by the instrument design.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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