(from L-R) A young Dr Orlando Alves da Silva, Dr Jean-Bernard Baron and Dr Henrique Martins da Cunha (Lisbon, late 1970s)


As part of my ongoing research into the development of the theoretical underpinnings of Dr Orlando Alves da Silva's clinical practice, I would like to share some of my work, and the rare photograph above.

In May 1977, a few days after his 31st birthday, Dr da Silva started in his new role as Director of Strabology and Orthoptics of the largest University Hospital in Portugal. His unique expertise in the complex dynamics of ocular movements and of ocular torticollis, was to prove essential in establishing the Postural Deficiency Syndrome (PDS); in the development of a treatment protocol using Active Prisms; and in identifying the role of the Proprioceptive System in PDS.


On his first day as the Director of Strabology and Orthoptics, Dr da Silva met with Dr Henrique Martins da Cunha, some 20 years his senior, and Director of Physiatry (Physical and Rehabilitation Medicine), a department that seemed to be completely unrelated to his own. Why?


Whilst Dr da Cunha was known for being very knowledgeable and for addressing difficult clinical cases, he was also considered as being somewhat eccentric, with few clinicians understanding or engaging with his work.  Before meeting Dr da Silva, Dr da Cunha had published on the importance of statics in clinical practice [1].  He had further observed that many of his patients with back pain also presented with specific postural characteristics, and with a set of signs and symptoms which he named Postural Deficiency Syndrome (PDS) [2]; when standing, such patients exerted more weight on their left foot (left foot support) and looked preferentially towards their left (gaze towards the left), with a smaller group exhibiting a mirror stance (right foot support and gaze towards the right). This particular stance made some of the patients look sideways when facing others, making them appear as if they were suspicious.


Dr da Cunha needed data to characterise the physical manifestations of these patients; to build a convincing case for wide recognition of PDS as a real and important clinical entity; and to divulge both his trigger point diagnostics protocol and his treatment (predominantly, segment repositioning and adoption of a set of postures).  But Dr da Cunha’s previous efforts to engage the Department of Ophthalmology by repeatedly referring patients with no obvious visual pathologies had created many tensions; Dr da Cunha had even bought a Maddox wing and had concluded incorrectly (not being an ophthalmologist himself) that his patients presented heterophorias!


Dr da Silva had been briefed on these tensions, and so offered to meet Dr da Cunha and one of his patients. At that first meeting, by using the cover test, Dr da Silva clarified immediately that the patient did not present with heterophoria; Dr da Silva was intrigued that the patient’s response to the Maddox wing changed as Dr da Cunha repositioned the patient's segments; Dr da Silva further observed that the patient presented with unusual dynamics of gaze; Dr da Silva quickly adapted the use of the Synoptophore to analyse these dynamics and was intrigued with the pattern presented by the patient.

Curious to investigate the visual presentations of Dr da Cunha’s patients, and within two weeks of starting as Director of Strabology, Dr da Silva set up the first joint clinic of Ophthalmology and Physiatry of its kind in the world, in a Department of Ophthalmology.  Once a week, Dr da Cunha selected 12 patients with rachialgia or myalgia from his Department of Physiatry, to be examined by himself and Dr da Silva in the Department of Strabology and Orthoptics.

In the following months, Dr da Silva fully developed Directional Scotometry, an innovative protocol using the Synoptophore and analysed the gaze of hundreds of patients; with Dr da Silva’s observations using Directional Scotometry, it soon become apparent that Dr da Cunha’s classification of left foot support, gaze towards the left (and right foot support, gaze towards the right) described above were incomplete, and that it was fundamental to analyse both the extent of rotation of each foot and the characteristics of the foot support, in particular, in the antero-posterior plane.

With Dr da Silva’s Directional Scotometry it become possible for the first time, to map a correspondence between gaze and foot support, and to establish a non-expensive, non-invasive well-defined, structured protocol to diagnose patients with PDS, that encompassed five PDS sub-types, named according to the variations in foot support. The fruitful collaboration between Dr da Silva and Dr da Cunha led to Dr da Cunha publishing his ground-breaking paper on PDS in 1979 [3], and many other publications were to follow.

Dr Jean-Bernard Baron’s background was both in ophthalmology and neurology, and throughout his carrier he experimented with many different approaches. Dr Baron had first met Dr da Cunha in 1976, and at Dr da Cunha's invitation he came to Lisbon in the late 1970s.  By then, the PDS diagnostic protocol developed by Dr da Silva and Dr da Cunha was already well established in their joint clinical practice, and Dr Baron visited Dr da Silva’s department.

Dr Baron explained to Dr da Silva how, contrary to what was (and still is) described in the literature, he treated convergence insufficiency with a specific left, base-out, horizontal low powered prism; Dr Baron asked to borrow a prism to demonstrate its effects on one of Dr da Silva 's patients with convergence insufficiency waiting for orthoptic treatment. Where Dr Baron had intended to use a 2-diopter base-out, horizontal prism (still referred to as Baron’s prism), Dr da Silva understood that Dr Baron required a 2-degree prism, which Dr da Silva converted to the closest 3-diopter prism, and it worked in improving the convergence of the patient! The possibility of using a left, base-out, horizontal low powered 3-diopter prism to treat convergence insufficiency was totally new to Dr da Silva and presented huge potential.  


Dr da Silva asked Dr Baron if the prism could also be used on the right side, as he reasoned that in optical terms the effect would be equivalent. Dr Baron explained, however, that the prism only worked on the left side due to the left-pathway being crossed.  Dr da Silva was unsure of the neurological basis of a left-pathway, but he was very keen to try this out. As soon as Dr Baron had left, Dr da Silva tested the 3-diopter, base-out, horizontal prism on the other patients with convergence insufficiency, but was unable to replicate the excellent results achieved earlier. Using Directional Scotometry and the PDS diagnostic protocol, Dr da Silva concluded that all these patients presented with PDS, and that the 3-diopter, base-out, horizontal prism was only effective in patients with the pure left PDS sub-type, one of the five sub-types of PDS that had been identified until then.  It had been a coincidence that the patient Dr Baron had tested happened to need a 3-diopter, base-out, horizontal prism.

In the following months, using the PDS diagnostic protocol and his knowledge of strabology, Dr da Silva was able to develop the use of specific low-powered, base out prisms for the left and/or the right eye, for each subtype of PDS, disproving Dr Baron's left-pathway concept; and to establish a new treatment protocol; and with Dr da Cunha, Dr da Silva continued to research the underlying neural mechanisms involved in this new treatment protocol to establish the fundamental role of the Proprioceptive System in PDS.

Dr da Silva’s collaboration with Dr da Cunha led to a paradigm shift:

- from Dr da Cunha’s interest of statics in clinical practice, to the importance of dynamics in the clinical practice with the introduction of dynamic testing including eye-hand test, and the analysis of the rotation and extension of the head with immediate observable and quantifiable results;


- from a single type of postural classification, based on left foot or right foot support, to a classification using Directional Scotometry that elucidated different types of positioning of both feet and different characteristics of foot support, in particular, in the antero-posterior plane as elucidated by;  


- from the invasive examination and diagnosis of patients using painful trigger points to a non-invasive inexpensive diagnostics protocol using the Synoptophore together with the dynamic analysis of head rotation and head extension;


- from a treatment based mainly on segment repositioning and mechanical means, to a tailored treatment for each sub-type of PDS with the provision of new visual inputs by means of specific active prisms;


- from the treatment of patients with rachialgia or muscular pain as the main symptom, to the treatability of patients who exhibit any of the diverse manifestation of PDS as the main symptom;


- from the belief that base-out, low-power prismatic lenses act mechanically at a local level to compensate micro-traumatisms believed to be at the base of a number of visual symptoms experienced by PDS patients, to the understanding that base-out, low-power prismatic lenses at very specific angles, prescribed following a clear protocol, are *active* and not passive.


Active Prisms provide stimuli that impact higher-order neural processes which are dysfunctional in PDS, and with the aid of Active Prisms these neural processes can regain functionality.

Dr Margarida Dolan, 02/05/2020

[1] Martins da Cunha, H. (1974) Alterações da Estática na Prática Clínica, ACTA REUMA. PORT. II, 2:335-342

[2] Martins da Cunha, H. (1977) The vertebral column and the Postural Deficiency Syndrome, VI Reunion sobre Patologia de la Columna Vertebral. Murcia. Espana

[3] Martins da Cunha, H. (1979) Syndrome de déficience posturale. Actualités en reéducation fonctionnelle et réadaptation, 4e série, L. Simon, Ed. Masson, Paris