Ocular Examination Flashcards
(22 cards)
External Examination
Adnexa
- Gross examination with naked eye.
- Use slit lamp or magnifying loupe if abnormalities detected.
External Ocular Surface Examination
Examination includes:
Conjunctiva and sclera.
Preferably using slit lamp.
Pen torch and magnifying loupe can be alternatives.
Direct ophthalmoscope at highest + lens for magnification.
Cornea Examination
Best done using slit lamp.
Examine corneal structures:
Endothelium, limbal structure, anterior angle.
Anterior Chamber
Fluid-filled space.
Should be optically clear.
Iris Examination
Evaluate color and pigmentation.
Crystalline Lens
Best examined under slit lamp.
Look for clarity and layered structure.
Vitreous Humor
Optically clear jelly-like substance.
Anterior vitreous examined with slit lamp.
Posterior vitreous examined with direct ophthalmoscopy or slit lamp with auxiliary lens.
Important Note
Avoid examining macular area first in undilated patients.
Causes pupillary light reaction and meiosis.
Wait for pupil to dilate again to view peripheral structures.
Optic Nerve Head
Key feature of fundus examination.
Exit point for ganglion cell fibers carrying visual signals.
Used as an anchor during examination.
Optic Disc
Oval-shaped structure with the optic cup in the center. Key features include cup-to-disc ratio, neuroretinal rim, and disc edge.
Cup-to-Disc Ratio
This is the ratio of size of the dimension of the optic cup to the optic disc. It is often difficult to detect the transmission from the optic cup to the neuroretinal rim, colour transmission is not always reliable, so we should look at other examples like the bending of the blood vessels when exiting the optic cup
Vessel Crossing
The retinal vessels have a tendency to cross each other as they spread across the retina. The variation in the anatomical pattern of these crossing are often important diagnostic signs of systemic disease although, they can also happened with arteriosclerosis with normal aging
Venous nipping
This occurs when an artery crossing over a vein and as a complication of arteriosclerosis or systemic hypertension the artery compresses the vein making it narrowed
Salus sign
This is when during the AV crossing the effect of the artery is deviate the vein to cross almost in a right angle triangle to the arterial vessel
Blood vessel tortuosity
Blood vessel tortuosity is important to evaluate with abnormal tortuosity and it can be indicative of systemic hypertension
Colour of blood vessels
The appearance of variation of colour across the lumen should always be notes. This is also known as copper or silver wiring
Calibre variations
The variations in the calibre of blood vessels should always be noted, sometimes knows as venous bleeding and focal arteriole narrowing
Retina and periphery
It is also important to note down the characteristics of peripheral retina. The presence, degree and distribution of the retina should also be noted as it determines the overall appearance of the fundus
Macula and fovea
Macula should be examined last to avoid pupil miosis in undialeted patients. The macula is an avascular structure with the fovea representing the centre point. The fovea is the part of the retina that gives us maximum visual acuity so any abnormalities should be detected
Disc Edge
The edge of the disc where it joins the retina represents a key attachment points of the retina with the underlying structure. The other key point of attachment of the retina is with the orra serrata around the equator, which can only be adequately seen with mydriasis and indirect ophthalmoscopy. The edge of the disc is sometimes well defined, particularly if there is a pigment ring around the edge however, if there is no pigment and the patient has a pale retina the disc edge can be poorly defined
Blood vessels
The retinal blood supply is important to examine because of its importance to supply blood to the inner layer of the retina and also for signs of any systemic disease which can be observed if there is changes to the retinal blood vessels. Diabetic retinopathy is one of the earliest signs of diabetes which can be noticed in patient and can be seen very easily by the presence of small dots, blot haemorrhages and hard exudates on the fundus. Generally the arterial vessels appear brighter and narrower whilst the veins appear darker red and thicker
A/V ratio
The A/V ratio expresses the diameter of the corresponding retinal arteries and veins as a ratio. When comparing the blood vessels should be same in terms of how many branches are coming out of the main vessel when exiting the optic disc. Generally a healthy eye has an A/V ratio of 2/3.
