On the heels of rediscovering Daniel Woolf comes another optometric giant who springs to life within the pages of his work, The Modern Treatment of Binocular Imbalances (MTBI).
My 1928 copy of Ray Morse Peckham’s MTBI is the second edition, the first having been published in 1926. The first nugget in the second edition actually comes in the Foreword by E. LeRoy Ryer, who writes: “When Peckham’s early work let the first ray of hope fall through a rift in the appalling darkness of my chaotic muscle work I was no mere beginner attracted by the first bright object that presented itself but a hardened skeptic who, like you, had found prisms ‘poison’ so often that I had acquire the habit of blaming the prisms and ignoring the faulty method of employing them. But the principles he presented were so transparently simple that it seemed not a question of adopting something new but a mere brushing of the dust off the old gold we know to be there all the while.”
Peckham was a strong proponent of the Kratometer, an ingenious device that worked on integrating the effects of lenses together with sliding round horizontal and vertical prisms (vertical bar for one eye and horizontal for the other eye) in a foray away from the phoropter into free space. What you see pictured here is the Kratometer from the patient’s view, followed by the Kratometer from the doctor’s view and a closeup of the stereoscope apparatus in place for training.
In his preface, Peckham writes of the significance of lenses, prisms, and active therapy in countering visual fatigue and the maintenance of visual equilibrium. Among other things, he elaborates on the significance of :
- “The establishment of well-traveled neuromuscular reflex paths when, for any cause, their development has been incomplete.”
- “The development of the sense of ocular orientation which includes speed of binocular fixation and the maintenance of equilibrium.”
- “Education of the sense of stereoscopic vision, when this is lacking.”
- “The release of conditioning tensions in the ocular muscles that prevent synchronized response to allied vestibular and visual sensations, as in many cases of dizziness, car-sickness and sea-sickness.”
- “The effects of artificial posture on the head which might tend to cramp the neck and bring pressure on the cervical bones on the cervical section of the spinal cord, for such pressure will interrupt the flow of neural energy to the intrinsic muscles of the eyes.”
Peckham was also a proponent of the temporary prescription of low amounts of base-in prism, and in particular its salient effects of reading. He suggested as well that patients with functionally progressive myopia or latent hypereopia might also benefit from an appropriate amount of base-in prism in their prescription. You may have heard his name through the optometric vision therapy procedure of “Modified Peckham Rock”, in which base-in prism is utilized as a way of inducing divergence, and wedging plus lens acceptance through vergence-accommodation inter-relationships.
As you read through the book you’ll find principles and insights that are often attributed to other sources but actually originated with Ray Morse Peckham, a type of Morse Code, if you will. Keep in mind again, that he wrote this book in 1928. Here are some examples:
a) When measuring fusional ranges, at both distance and near, it is a very unfavorable sign if recovery occurs beyond the range of a few prism diopters of the break point. “It is better to find a rather low total abduction with quick recovery than to make a high abduction with poor recovery.”
b) To obtain their maximum value, divergence measures should precede convergence measures because of induced tension and hysteresis, which Peckham called hyper-tonicity of the medial recti as occurs in esophoria.
c) Multiple measures with prism are advised to probe evidence of tension, stress, and susceptibility to fatigue. Compare speed tests involving prism jumps to smooth prism measures. “It is the quality of responsiveness that is essential, irrespective of the quantity of prism power overcome.”
d) “If there is freedom from stress, ductions are high. If there is tension, if there is obstruction to the delivery of the commands of the central nervous system, ductions are low.”
e) “It is the lack of attention in the secondary visual centers in the cortex of the brain that is the cause of intermittency of vision, or intermittent suppression.”
You’ve no doubt heard occupational therapists refer to “low tone”, and Peckham was very mindful of the significance of low tone on the development and breakdown of binocular vision. Consider his holistic approach, in which he noted that low tonicity found on ocular tests may be indicative of general bodily fatigue. He advised that in addition to consideration of prism and therapy procedures, “the patient should also be advised to take plenty of outdoor exercise and should watch the diet and intestinal action.”
Speed of stereopsis and neuronal plasticity appear to be new concepts, but Peckham laid the groundwork for these in his book in 1928. Here is one of the geometric slides he used for testing through the Kratometer with the stereo slide holder in place.
Peckham observed: “The old tradition that stereoscopic vision cannot be trained if it is not developed within the first few years of one’s life is found without foundation now that the Kratometer has made possible the development of vision in highly amblyopic eyes that did not respond to the less direct and forcible methods previously employed. For we find that we we train the faculties of attention, quick perception, and immediate muscular reflexes, that stereoscopic vision can be developed therewith.”
Perhaps most striking of all is the revelation that Peckham wrote about the significance of MFBF (Monocular Fixation in a Binocular Field) and the binocular treatment of amblyopia as early as 1924. It is worth reminding ourselves that the importance of a binocular approach to amblyopia was employed by Claud Worth in his creation of the Amblyoscope, forerunner of the Clement Clarke Synoptophore. Regarding amblyopia, Peckham introduced slides such as the one below for principles of MFBF and the push/pull methods of treatment, having a central black figure with a red border that cancels through a red lens.
Peckham writes: “Put one or two smoke color lenses in front of the good eye to reduce the luminosity to that eye. In this way, with illumination reduced to the good eye but kept at full strength to the amblyopic eye, the latter will receive stimuli equal to the stimuli entering the good eye … Daily improvement in acuity and fusional habit will be noticed. Check correcting lenses frequently and change as necessary. The amblyopic eyes, as acuity increases, will doubtless need several lens changes before the final correction is established … This method of simultaneous development of vision and binocular functioning, using the stimulus of bright red for the amblyopic eye, and reducing the stimulus to the better eye by filtering out the red from its image, originated with the writer in 1924, while experimenting with the Kratometer in comparison with older methods of visual development.“