Page 9 - BOAF Journal 1 2012:2707

Behavioral Optometry
BOAF
Volume1 Number1 2012
Very often these inefficient head movements are accompa- nied by head tilts and further investigation has revealed sco- liosis in many cases.
Checking functional visual fields in these cases will often show substantial restrictions and occasionally dural torque 5 (misplacement or tilting of the physiological blindspot)
4) Incommittent Hetero- phorias / Tropias
When phorias or tropias vary in different angles of gaze, variable compensatory head tilts / turns can result with resul- tant adaptations through the body’s structures. This can lead to an increase in wear and tear on the skeletal and muscular system. This effect will be ag- gravated if the individual also suffers from arthritic problems.
5) Strabismus, amblyopia or blind eye
When an individual is effec- tively “one eyed” either due to amblyopia, suppression or blindness, it is visually efficient to rotate the head to give a larger available field for the “good” eye to compensate for field loss by obstruction of the nose. This acquired cyclic cer- vical rotation can lead to shoul- der and pelvic girdle twists. Neck, back, hip and leg prob- lems can result. The individual may present with walking, gait and balance anomalies.
6) Poorly fitting specta- cles
One of the worst cases one sees of spectacles causing structure problems are seen in
the wearing of self prescribed Ready Reader 1⁄2 eyes. When people wear these 1⁄2 eyes, the top of the lens is several mm above the bridge of the nose. When looking over these to see in the distance, a marked drop in chin position is needed.
Badly fitting bifocals and varifocal lenses, particularly oc- curring when dispensed with “heavy” lenses will slip down the nose positioning the reading area too low for comfortable reading posture. The effect of this is to read with the chin lifted causing strain in the neck and shoulders.
It is also obvious when you look at these postural consid- erations that high powered and aspheric lenses need to be cen- tered vertically as well as hori- zontally, as recommended by the designers and manufactur- ers of these lenses.
7) Working on Visual Dis- play Units
If the screen is set too high, postural problems relating to a raised neck will occur with vari- focal. This situation will be in- creased when an individual is wearing a bifocal where the reading add, designed for a reading focus, is too close a range for VDU, hence the indi- vidual will lean forward and raise the chin and increase that chin rise in order to look through the segment. Excessive strain on the shoulders and neck will make the individual tired, inefficient and a likely RSI sufferer.6 Patients suffering from depression, stress, mild trau-
matic brain injury, Parkinson's
and Alzheimer's diseases 7,8,9,10 as well as children with learning difficulties 12 may experience a restricted range of clear, near vision, associated with a re- duced functional field of vision. These patients will lean in to- wards the screen leading to RSI (repetitive strain injury) in lower back, neck, shoulders, elbows and wrists, and yet the origin of their problem is visual.
8) Dural Torque and Cra-
nial's 5
Dural torque is a condition where the plotted physiological blind spot is shifted from the normal expected position. It can be displaced nasally, tempo- rally, superiorly or inferiorly and rotated.
The outer covering of the spinal column, brain stem, brain and optic nerve is referred the dura mater. Dural torque is normally associated with a “pulling” of the dura mater. This change is represented by an actual shift of the physical posi- tion of the blind spot (where the optic nerve enters the eye). This position should be ana- tomically stable in the eye.
Under the circumstances of trauma, there is often a mis- alignment of the bones of the skull, atlas and axis junctions and misalignment of the cranial bones’ junctions which may also be associated with mall position of the spine, which in
-9-