Consecutive exotropia refers to a manifest exodeviation following surgery to correct esotropia. Surgery is common for early onset esotropia, particularly congenital/infantile esotropia. Congenital/infantile esotropia is usually accompanied by several ocular phenomena, including: latent nystagmus, dissociated vertical deviation (DVD) and overaction of the extraocular muscles, especially the inferior obliques. Additionally, since there is a disturbance in normal binocular vision, anomalous correspondence (AC) is often present. Despite this poor or limited binocularity, interventions to increase fusional ability are possible and should be considered.
Nystagmus is a relatively common clinical condition that remains a therapeutic enigma. We present a case in which soft contact lenses were prescribed in a young adult with congenital jerk nystagmus. Immediate and large improvements in both motor and sensory function, as well as cosmesis, were found, with enhancement one week later following constant lens wear. Use of soft contact lenses in these cases represents a simple, effective and inexpensive therapeutic option.
The purpose of this study was to determine if external oculomotor visual feedback can be conceptualized and used by young children (5-10 years of age) to improve their eye movement control. Horizontal eye movements of the right eye were monitored objectively in five visually-normal children and one nystagmat under binocular viewing conditions; in addition, two visually-normal adults and one adult nystagmat were tested as controls. All subjects were instructed to reduce their horizontal fixational eye movements within preset but variable criterion ranges (+/-1.75 and +/-3.5 degrees) while attempting to fixate accurately on the video image of a storyteller (7degrees H x 11degrees V) displayed at the bottom of a television screen placed at near (33cm) along the midline. If successful, the video portion of the image remained visible; if not, the video portion was extinguished, and only the audio portion remained until accurate fixation was re-established. A similar paradigm was followed for saccadic eye movements. All children and adult subjects understood the instructions and were successful in controlling their eye movements within the specified criterion level 90% of the time by the end of one training session. Moreover, the young child with nystagmus was able to reduce his nystagmus in both frequency and amplitude by the end of the first session, and in the subsequent three sessions. Our findings indicate that oculomotor-based visual feedback training appears to be a viable alternative to oculomotor auditory feedback and other more conceptually complicated procedures in young children, as well as in other diagnostic groups, to improve oculomotor control.
Several training programs have been attempted with varying degrees of success in patients with congenital nystagmus. A new comprehensive, multi-sensory, scientifically-based, integrated approach to training oculomotor control in these patients is discussed. Training involves the use of auditory, visual, and tactile feedback in conjunction with higher-level control aspects including visual attention, visual imagery, and relaxation paradigms.