HISTORY ELICITATION
As with other disciplines, examination of an eye patient starts with the details of name, age and gender. Patient's religion is not so important. Trachoma is common amongst Muslims especially if they pursue purdah habit. Family history must be gone into when the case has a hereditary basis or is a contagious one.
Patient's domicile must be elicited to find out whether the patient is from an endemic area for diseases such as trachoma and leprosy. Nature of patient's occupation is equally important. Industrial workers and those working with metals and glass are prone to injuries.
The socioeconomic status has some bearing on conditions such as vitamin A deficiency, phlycten and trachoma. So, patient's socioeconomic status must be elicited.
In undergraduate clinical examination, much of the above details are not mentioned to examiner except when specifically required. So much so many a time, after ‘name, age and gender’, the candidate jumps to patient's complaints.
The patient's complaints are recorded in chronological order and that too in patient's own words. The complaints alone are recorded first. Later, under “Present history”, the complaints are elaborated – again in chronological order. In clinical examination for under graduates, the “Past history” is usually not mentioned separately. It is clubbed with “Present history”.
The candidate must be careful in mentioning which side eye he is talking about – right, left or both eyes— while presenting “Complaints” and “Present history”. 3(The same concept must be applied when presenting findings of ocular examination and when mentioning diagnosis and treatment).
EXAMINATION
The clinical examination of an eye case starts with general study of the patient. Attention must be directed towards any congenital defects the patient has such as six fingers, hypogenitalism, abnormal facial features and such other abnormalities as preauricular skin tags. In general examination signs of congenital and acquired syphilis, of leprosy and tuberculosis must be looked for. One should not miss examining nasal cavity, ear and sinuses.
The examination of eye begins with the face, eyebrows, palpebral fissure and the eyeballs. Obvious squint should not be missed. So also VII nerve paralysis. Quick examination of eye can be done by three maneuvers: (a) Pulling down the lower lid and pressing over the lacrymal sac area (b) Everting upper lid (c) Keeping both lids wide open. The last step facilitates study of anterior segment, pupil, lens and checking of ocular movements (Figs 1.1A to C). The illumination can be with torch light. But better details are seen if examination of eyes is carried out by oblique illumination along with loupe (Fig. 1.2) or with slit-lamp (Fig.1.3).
In the anterior segment, the three essential points to be looked for are (a) state of cornea, (b) pupil and (c) depth of anterior chamber (A/C). It is not possible for a beginner to assess anterior chamber depth accurately. The eclipse test is useful— if light is shone from one side into anterior chamber, if the chamber is shallow, the other side half of the iris will be in shadow due to convexity of iris.
Figs 1.1A to C: The three maneuvers for a quick examination of eye. In the first step, the lower lid is pulled down to examine the inferior palpebral conjunctiva and at the same time lacrymal sac area is pressed to check for any regurgitation (Fig. 1.1A). In the next step, the upper lid is everted to examine the upper palpebral conjunctiva (double eversion can be done at this stage, if needed) (Fig. 1.1B). In the final step, the lids are kept apart to examine the anterior segment of eye including pupil and lens (Fig. 1.1C)
Pupil is studied for its size, shape, situation and reaction to light – both for direct and consensual.
Patient's vision should be recorded. The distance vision is recorded with the help of Snellen's chart (Fig. 1.4). The illumination at chart should be at least 20 foot candles. The patient is seated 20 feet from chart. The top letter of the chart is read by a person with normal vision at a distance of 60 meters, the next line at a distance of 36 meters and so on (3rd line at 24 meters 4th line at 18 meters, 5th line at 12 meters, 6th line at 9 meters and 7th line at 6 meters distance from chart).
Fig. 1.4: Snellen's chart for testing acuity of distance vision. Usually there are seven lines (rows). The seventh line is 6/6 (The eighth line in the chart is for 5 meter distance)
If a person reads the 7th line at a distance of 6 meters, then it is stated that he has a vision of 6/6, which is normal vision. If one can read maximum, for instance, only the 4th line at the same 6 meters distance then he is said to be having a vision of 6/18. If at 6 meters if a person is unable to read even the top line, then the student shows his fingers from 5 meters to one meter 8distance from the patient. If, for example, the patient sees the finger at a distance of 3 meters, then he is said to be having a vision of 3/60. If a patient is not able to see the finger even at a distance of one meter, then he is asked to count the fingers at 50 cm (written as CF 50 cm). Even if this vision is not present, observer's hand is moved across the eyes. If this is appreciated then it is HM +. Finally, if even HM is not present, the patient is asked if he can perceive a light thrown into his eyes. If he can see light then projection of light is checked by shining the light from all four quadrants. While checking this, patient should be asked to look straight ahead and not at the source of light.
Near vision is tested either with Roman test type (notation used is N6, N8, N12, N18, etc.) or with Jaeger chart (expressed as J7, J6, J5, etc) (Fig. 1.5).
Fig. 1.5: Near vision chart which is a hand held illuminated one. But it is ideal that near vision is checked under usual room illumination
The refractive state of patient's eye is tested objectively by the procedure known as retinoscopy using retinoscopy mirror and trial set. Instead of retinoscopy mirror, many use streak retinoscope, which is easier and has its own source of light.
Digital study of ocular pressure must be done. This is carried out by keeping one index finger on the closed upper lid of patient and with the other index finger gently depressing the eye through the closed lid. The fluctuation of globe under the lid is felt by the first index finger (Fig. 1.6). This is very difficult to be appreciated by a beginner. But with experience any change in ocular pressure is appreciated. Tonometer such as Schiotz tonometer (Fig. 1.7) or applanation tonometer (Fig. 1.8) gives the correct value of intraocular pressure (Fig. 1.9).
Fig. 1.6: Assessing ocular pressure with fingers. One finger is stationary and a gentle short pressure is applied to eye over the lid with the other finger “to feel the pressure of the eye”
Fig. 1.7: Schiotz tonometer which is used for measuring the intraocular pressure (IOP). It is one type of indentation tonometer
Checking the color vision may not be needed for the undergraduates in the university examinations. But to know it is essential for later life, especially if the student takes up administrative post later on. Usually color vision is checked with Ishihara chart (Figs 1.10A to F).
There are four sets of lettering in the chart:
- In one set of charts the number in the chart can be read by all.
- In another set of charts the number is read differently by persons with red-green blindness.
- In certain other set of charts red-green blind cannot read the numbers, which can be read by normal persons.
- In another series of charts the normal does not see any number while the red green blind reads a number.
Usually color blindness can be for red (protanopes and protanomalous) or for green (deuteranopes and deuteranomalous). If blindness for blue exists it is known as tritanopes. The last condition is very rare (The other methods of testing color vision are lantern test using Edridge green lantern, Fransworth Munsell 100 hue test, Hologram's wool test and Nagel's anomaloscope).
Slit-lamp (biomicroscopy) study, fundus examination (with indirect and direct ophthalmoscope or with 90 diopter lens) (Fig. 1.11), field analysis and other specialized tests such as tonometry and gonioscopy to study angle of anterior chamber are not usually required for undergraduates.
Method of detailed examination of each part of the eye and its adnexa, if needed, is dealt with in the chapters dealing with them.
