Early adaptive Syndrome is a syndrome of observations characteristically seen during early stages of visual reorganization to meet (adapt to) adverse visual stress. The observed visual behavior changes are related to another syndrome, the Non-malingering Syndrome. The significant differences are that in the Early Adaptive Syndrome distance acuity may still be within the normal limits and there is not the restriction that the refractive measure be from emmetropia to low hyperopia. The Early Adaptive syndrome is recognizable as early changes when no refractive deviation has been previously seen, and when the individual has apparently refractively stabilized.
Quite common among practitioners who are engaged in programmed visual care practices, is the feeling or impression that a particular individual warrants closer observation. This is sensed in spite of the fact that refractive measurements are in accordance with previous visits. We too have experienced this phenomenon. The question is how can this be observed? What in common is there about several of such individuals to cause this concern? What are the red flags? Is it just a feeling or are there some measurable observations (in quality and quantity)? Is there any sequential order to such observations, and is there a sequence in the observation pattern from this stage to the later stages when refractive changes can be measured?
This syndrome has resulted from an effort to evaluate and understand this early "change which is so nebulous as almost not to appear as a change. The name has been chosen to indicate that this is an early phase of a change. While the picture is by no means complete in all details at this time, it has proven of sufficient clinical value to warrant presentation.
Some individuals who manifest the Early Adaptive Syndrome will later manifest the Non-malingering Syndrome. The Non- malingering Syndrome seems to be a special case of intensified Early Adaptive Syndrome.
Syndrome Description:
Four observations have been consistent in the observed clinical picture. These are:
1. Reading and writing is habitually done inside of the measured Harmon distance.
2. Visual acuity at near (reduced Snellen at 16 inches) is lower than distance Snellen acuity. (Improved when test card is moved closer.)
3. Bell retinoscopy registers a delayed shift into against motion (closer to the patient than the expected).
4. Book retinoscopy measures in low with motion (at the appropriate reading levels).
Other observations frequently noted are a slight drop in the Wirt stereopsis score and difficulty in the Keystone progress of fusion series (usually first at near, and later at far). Pupils many times are dilated more than expected.
An interesting side observation is that children will often show difficulty with the Psuedo-isochromatic Color plates. This is of interest for the problem seems more one of difficulty in organizing the pattern rather than differentiating the colors.
Discussion:
While all of the observations of the Early Adaptive Syndrome are contained within Non-malingering Syndrome, there are considerable differences. Some of these differences can be more readily understood when the differentiation is made within the two syndromes.
A. Acuity
1. Distance visual acuity in the EAS (Early Adaptive Syndrome) is at the expected level in accordance to the refractive state and age. As the individual moves in time and adaptation, first there is a qualitative loss, and later there may be a measurable visual acuity loss.
2. Near visual acuity is lower than distance visual acuity. This is true in both syndromes. However, because the NMS (Non-malingering Syndrome) has a lowered distance acuity the near acuity is usually reduced more than in the EAS.
B. Refractive measurement
1. In the NMS the refractive status is from Plano to low amounts of hyperopia. In the EAS it may be in this range, but the similar pattern is often seen with change into more myopia, astigmatism or adverse hyperopia. The EAS can also be seen with the presbyope who is at an early stage of needing plus or more plus at near.
C. Subjective symptoms
1. The person showing the EAS may or may not be aware of any difficulty. It is not uncommon to see the syndrome without any awareness of specific symptoms. A definite pattern of symptomology is noted with the NMS.
D. Incidental
1. The EAS is seen much more frequently than the NMS. This should be expected since the latter is but a specific type of intensification of the first.
Some Questions:
It seems necessary to ask some questions at this point. How does reading closer it easier for the individual? The most common answer to this question is that it in effect gives magnification. Magnification yes, but at what cost? A basic rule in the developmental philosophy is that an organism always seeks what to him is optimal behavior. How can magnification, unless it is very valuable under the circumstances, be worth the considerable greater energy demand to perform at this restricted range.
Secondly, how is it possible to measure a difference in acuity at 16 inches than it is at 20 feet when the ability to spatially shift visual focusing is not restricted? The near acuity chart and the distance acuity chart subtend the same visual angle. How then can a child have 20/20 acuity at 20 feet only 20/40 acuity at 16 inches?
Thirdly, how can book retinoscopy measure in with motion? We have found this measurement as high as to require a +2.50 diopter lens to neutralize the motion. How is it possible to read when the eye is "out of focus" to this degree? Further, how does the organism find it advantageous to perform with such a pattern?
While we have some opinions concerning the answers to these questions, the fact that they are opinions rather than descriptions born out of research dictate that it would be best to await further study before we present them. It is apparent, that traditional theory, while it can "justify" some of the observations, does not explain them satisfactorily. The mere number of instances of observation rule out the possibility that they are exceptions to the theory as well as the possibility that the observations are in error.
It would be very easy to say that "accommodation" was lacking in function, but does this really describe what we are seeking or is it a symptom. Is it a cause or is it an effect? If this were really the problem, and when we accept the developmental principal of an organism attempting to seek optimal behavior, how does reading in a posture demanding more "accommodation" answer the difficulty? The immediate answer will be to get more convergence to aid accommodation. How then, can an individual accept a situation where the accommodation measures 2.50 diopters out of focus?
Another interesting observation helps complicate the picture of a simple accommodative-convergence theory. A hypothetical basis for such a theory is a comparatively fixed center of rotation of the eye. This has proven not to be the case. Further, if one accurately measures the inter-pupillary distance when fixating at 20 feet and again when fixating at 16 inches, the difference should be equivalent to a calculable difference. Yet when this is done, a very significant number of people vary from the calculable difference and to a significant degree. Thus it becomes apparent that there are ways for an individual to keep a macular match in alignment other than by convergence.
We have asked many questions and given few answers. We have found the questions to be of value because they have allowed us to find a direction in searching for answers. When the right questions can be asked, a direction should follow. The direction may not be the same for all individuals, and this is as it should be. The more people who will search for answers to the questions, the better the opportunity for a broader explanation at a more reliable level.
The Early Adaptive Syndrome in Clinical Application:
The first clinical value of the EAS has been to allow us another method of viewing the sequence of observations in time. It allows another measure of where in the process of adaptation the individual is. This is of particular value since it is not restricted to the primary adaptation, but is again seen when a secondary or when the earlier adaptation has not continued to serve the individual as an adequate means of organization. As an example helps us to observe and understand the youngster who has seemingly stabilized in myopia begins to make a further adaptation. It also allows us to observe when the older youngster approaching presbyopia commences to make adaptive changes even though he can still read "satisfactorily". In fact, we have seen the Non-malingering Syndrome make its appearance at this age level. For some reason, optometrists are not as disturbed when they do not see the Non-malingering Syndrome at the time of presbyopia. They accept much easier the fact that the distance acuity loss and all else that is seen, is a result of the near problem. As such, when the near visual problem is taken care of, the distance difficulty will not be measurable later. Why should there be this difference in thinking?
The greatest clinical implication of either the EAS or the NMS to us is that when present, one has much more liberty in directing the future with lenses. More emphasis can be placed on alleviating the near problem, and less credence can be given to the absolute optical compensation of the refractive measurement. As an example, let us look at the following two hypothetical cases:
Individual I Acuity: Far 20/40
Near 20/60
Bell Retinoscopy: 12/14
With +.50: 15/17
Book Retinoscopy: +0. 75
Done with +. 50 on: Plano Lenses
Static Retinoscopy (#4): -. 50 0. U.
Individual II Acuity: Far 20/40
Near 20/20
Bell Retinoscopy: 20+/20+
With +50: 20+/20+
Book Retinoscopy: Plano to -.25
Done with +. 50: -. 25 to -. 50
Static Retinoscopy (#4): -. 50 O. U.
From these findings alone a great deal of difference can be seen. Not only can a great deal of difference be seen, but the application of lenses will no doubt be quite different and the predictions will be very much different. The predictions would be that Individual 1 has a better than equal chance of regaining normal acuity when the proper amount of plus (in piano-plus add form) is used constantly at least for a period of time. At the same time, the prediction would be that Individual II given the same lens would not only fail to move towards standard acuity, but more than likely progress into myopia at a more rapid rate. We do not mean to imply by the abbreviated set of findings that this is all the tests we would do, or all that we would base our lens formula upon, for it is not. The abbreviated findings above are used to show only the findings directly related to the observations of the EAS.
When the Early Adaptive Syndrome is observable, youngsters usually will accept single vision plus even when it does reduce distance acuity somewhat. In fact, they usually will insist that the lenses do not cause a blur. However, when the near acuity begins to show better resolution, the bell retinoscopy measure begins to show better resolution, the bell retinoscopy measure begins to move outward, and book retinoscopy moves towards piano (when tested without the lenses) then there is usually an awareness of a distance blur. Even when the distance blur is not subjectively recognizable at this stage, we do not chance single vision plus beyond this point. We have followed youngsters where we thought it might be safe go along with the single vision after this reorganization, only to find a move into myopia from 6 months to one year later. When a Plano-plus add is used, the same is not true.
Summary
The Early Adaptive Syndrome is a syndrome composed of four visual measurements which are observable during the early stages of visual adaptation. The adaptation appears to be a reorganization in an effort to resolve an adverse near-point visual problem. The Non-malingering syndrome described earlier in the literature is a specific intensification of the Early Adaptive Syndrome.
The Early Adaptive Syndrome is valuable in two ways: 1. Allowing the optometrist to understand the patterning of adaptation. 2. An aid in determining the freedom the optometrist has in directing the future visual reorganization with lenses. The pattern is seen at all levels of refractive measurements and ages. An individual may show the pattern more than one time.