Page 25 - BOAF Journal 1 2012:2707

Behavioral Optometry
BOAF
Volume1 Number1 2012
The horizontal and vertical measurements of the plotted physiological blind-spot are taken in millimeters and the percentage of restriction ob- tained by consulting the com- putation table furnished with the Caecanometer. To use this ta- ble, the doctor finds the number of millimeters equal to the verti- cal measure in the first column on the left margin and follows this row over until he reaches the column headed by the measurement found for the horizontal meridian. The number found where the appropriate row and column intersect is the percent by which the nerve- head is smaller than the ex- pected plotted size.
Example: 13 x 23 = -30%
It is possible with certain patients and dependent upon a certain set of conditions to plot a smaller than normal physio- logical blind-spot using the charting technique of moving the test object from within the scotoma our until the patient sees it - which is the procedure for pathology detection. How- ever, it has been established as the best procedure in field stud- ies to use the technique that gives the most obvious signs with the least effort for the pa- tient and the doctor. For this
reason and because patient reactions are far more reliable and repeatable, Davidsen con- siders it imperative to use the technique of charting from the seeing paracaecal area to the blind-spot. Davidson further found the correlation between
the blind-spot plotted size and foci of infections were more di- rectly related when plotting in this manner. the percentage chart and all literature on the technique of caecanometry are based on the physiological blind-spot plotted in this matter.
Differential Diagnosis
With regard to the differen- tial diagnosis of the cae- canometric charting, determin- ing the presence of a focus of draining infection above the clavicles is a relatively simple matter. Whenever the plotted size of the nerve-head is less than 17x25 millimeters, a drain- ing infection is significantly pre- sent. There is a temptation to say that the greater the per- centage of constriction, the greater is the infection but this would be overlooking another variable which is the anatomical structure of the individual. There is a close relationship between the paranasal sinuses and the orbital cavities and between the teeth and the maxillary sinus.
The active individual who is a deep breather and whose power of recuperation and de- fense is quite high may have a rather severe infection without a correspondingly great constric- tion. However, if this type of individual should become ill and spend some time in bed, they can succumb to the infection and the plotted nerve-heads will show a correspondingly in- creased constriction. The inac- tive individual of the desk worker type who is a hypo-
ventilator whose reparation and defense power is low may show a great constriction while host to a much less severe infection.
It would appear in cae- canometry that one is determin- ing not the the degree or sever- ity of the infection but the effect of the infection on the organism. There is further a variation in the potency of bacteria and their toxins. The early work of David- sen indicated that the bacterium may vary from tooth to tooth or right or left sinus in the same individual. Bacteria differ in their circulation rate from day to day and during the day. All of these will create different degrees of constriction of the plotted physiological blind-spot.
For a differential diagnosis, three basic prerequisites should be kept in mind:
1. Constricted nerve-head chartings to give positive evidence of the presence of infection and changes in the plotted nerve-head size which occur in comparing basal, non-basal and/or pro- vocative chartings.
2. Symptoms or patient com- plaints.
3. Careful observation of the patient.
Exact location of the nerve- head is unimportant to the di- agnosis of focal infection. Dis- placement from the expected location is probably indicative of anatomical differences, anoma-
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