A New Clinical Method for Visual Function Evaluation Including Estimation and Measurement of Therapeutic Effectiveness: Lessons From Infantile Nystagmus Research.

Purpose: To translate infantile nystagmus system (INS) research into easily understood, clinically relevant terminology and suggest modifications to research and clinical testing, data and clinical interpretation, and therapeutic choices and evaluation.

Methods: A clinical method is presented using only three best-corrected visual acuity measurements of patients with INS, whereby (1) a measure of the quality of visual acuity across the visual field is possible; (2) pre-therapy estimates of post-therapy improvements in peak acuity and the high-acuity range of gaze angles are possible; and (3) more realistic visual function outcome measures of therapy are available to the practitioner.

Results: The application of the high-acuity field quality spreadsheet to the analyses of patients with INS (before and after therapy) results in a quantitative measure of visual function based on three visual acuity measurements.

Two Electrical Engineers, One Problem, and Evolution Produced the Same Solution: A Historical Note.

This note adds historical context into solving the problem of improving the speed of the step response of a low-order plant in two different types of control systems, a chemical mixing system and the human saccadic system. Two electrical engineers studied the above problem: one to understand and model how nature and evolution solved it and the other to design a control system to solve it in a man-made commercial system. David A.

Topical lambda-cyhalothrin in reducing eye oscillations in a canine model of infantile nystagmus syndrome.

Purpose: To determine the ocular and systemic safety of using topical Lambda-Cyhalothrin (LCL) in a canine model of infantile nystagmus syndrome (INS). The rationale for this proposal is based on a case study of a patient whose INS improved after inadvertent ocular exposure to a pyrethroid pesticide containing LCL.

Methods: After in-vitro safety testing and IUCAC approval, we studied increasing concentrations of topical LCL drops (0.

Foveation dynamics in congenital nystagmus IV: vergence.

Purpose: To evaluate foveation dynamics and characteristics of vergence eye movements during fixation of static targets at different distances and while tracking a target moving in depth in a subject with congenital nystagmus (CN).

Method: Eye movements of a well-studied subject with CN were recorded using the magnetic search coil technique and analyzed using the OMtools software, including the eXpanded Nystagmus Acuity Function (NAFX).

Results: Both the phase planes and NAFX values during fixation of targets at various near distances were equivalent to those during fixation of a far target.

Ocular Motor System Control Models and the Cerebellum: Hypothetical Mechanisms.

To review our studies and "top-down" models of saccadic intrusions and infantile nystagmus syndrome with the aim of hypothesizing areas of cerebellar connections controlling parts of the ocular motor subsystems involved in both types of function and dysfunction. The methods of eye-movement recording and modeling are described in detail in the cited references. Saccadic intrusions, such as square-wave jerks and square-wave oscillations, can be simulated by a single malfunction, whereas staircase saccadic intrusions required two independent malfunctions.

Longitudinal Studies and Eye-Movement-Based Treatments of Infantile Nystagmus Syndrome: Estimated and Measured Therapeutic Improvements in Three Complex Cases.

Introduction And Purpose: To demonstrate the utility of using eye-movement data to reveal the diagnostic characteristics of infantile nystagmus syndrome (INS), determine treatment, and both estimate and document therapeutic improvements in three patients with well-developed foveation periods, fairly broad, lateral gaze "nulls," head turns, strabismus, and complex, multiplanar nystagmus.

Patients And Methods: Infrared reflection, magnetic search coil, and high-speed digital video systems were used to record the eye movements of INS patients, pre- and post-Kestenbaum null-point correction surgery (horizontal or vertical). Data were analyzed and estimations made, using the eXpanded Nystagmus Acuity Function (NAFX) that is part of the OMtools toolbox for MATLAB.

Clinical and ocular motor complications of extraocular muscle extirpation for infantile nystagmus syndrome.

Purpose: To describe the effects of extraocular muscle extirpation performed after previous eye muscle surgery in a 20-year-old woman with infantile nystagmus syndrome (INS) for whom we have 19 years of follow-up data.

Methods: Clinical examinations were performed. Eye movement data analysis was carried out using the eXpanded Nystagmus Acuity Function (NAFX) and longest foveation domain (LFD).

Development and surgical removal of an epiretinal membrane in infantile nystagmus syndrome: a new type of oscillopsia.

Purpose: To report and discuss a focal oscillopsia in a small area of the visual field produced by, and after the removal of, an epiretinal membrane (ERM) in an individual with infantile nystagmus syndrome (INS) since birth with no associated afferent visual deficits.

Study Design: A retrospective case report.

Methods: A chart review, including clinical and electrophysiological data.

Effects of augmented tenotomy and reattachment in the infantile nystagmus syndrome.

Purpose: To test the hypothesis that augmented tenotomy and reattachment surgery (AT-R), which involves placing an additional suture in each distal tendon during the 4-muscle tenotomy and reattachment (T-R) or other infantile nystagmus syndrome (INS) procedures, could increase the beneficial effects of many types of extraocular muscle (EOM) surgery to treat INS.

Methods: Both infrared reflection and high-speed digital video systems were used to record the eye movements in 4 patients with INS before and after AT-R surgery. Data were analyzed using the eXpanded Nystagmus Acuity Function (NAFX) that is part of the OMtools software.

Fusion maldevelopment (latent/manifest latent) nystagmus syndrome: effects of four-muscle tenotomy and reattachment.

Purpose: To examine the waveform and clinical effects of the four-muscle tenotomy and reattachment procedure in fusion maldevelopment nystagmus syndrome (FMNS) and to compare them to those documented in infantile nystagmus syndrome (INS) and acquired nystagmus.

Methods: Both infrared reflection and high-speed digital video systems were used to record the eye movements in a patient with FMNS (before and after tenotomy and reattachment). Data were analyzed using the eXpanded Nystagmus Acuity Function (NAFX) that is part of the OMtools software.

A unifying neurologic mechanism for infantile nystagmus.

Lateral-eyed afoveate animals use the subcortical accessory optic system to generate accurate responses to full-field optokinetic input. When humans rotate their eyes to pursue a moving target, the visual world sweeps across their retinas, creating a contraversive optokinetic stimulus. Humans have developed a cortical foveal pursuit system that suppresses the perception of this full-field optokinetic motion during active pursuit.

Smooth-pursuit changes after the tenotomy and reattachment procedure for infantile nystagmus syndrome: model predictions and patient data.

Purpose: Patients with infantile nystagmus syndrome (INS) often cannot quickly locate new visual targets or track moving objects. Dynamic demands on visual function are not measured by static measures (eg, visual acuity); they require time-sensitive measures. The authors investigated how dynamic properties of INS (pursuit-target acquisition times) were affected by the tenotomy and reattachment (T&R) procedure in both patients with INS and behavioral ocular motor system model predictions.

Effects of topical brinzolamide on infantile nystagmus syndrome waveforms: eyedrops for nystagmus.

Background: Recent advances in infantile nystagmus syndrome (INS) surgery have uncovered the therapeutic importance of proprioception. In this report, we test the hypothesis that the topical carbonic anhydrase inhibitor (CAI) brinzolamide (Azopt) has beneficial effects on measures of nystagmus foveation quality in a subject with INS.

Methods: Eye movement data were taken, using a high-speed digital video recording system, before and after 3 days of the application of topical brinzolamide 3 times daily in each eye.

Two hypothetical nystagmus procedures: augmented tenotomy and reattachment and augmented tendon suture (Sans tenotomy).

Purpose: To review the hypothetical mechanism and therapeutic benefits of the four-muscle tenotomy and reattachment (T&R) procedure using knowledge accrued over the 10 years since its proposal; to describe an augmented tendon suture (ATS) technique to improve the procedure based on one of the originally suggested alternative methods (mechanical); and to hypothesize a new ATS procedure to achieve the same therapeutic benefits without extraocular muscle tenotomy or reattachment to the globe.

Methods: Standard surgical methods were used.

Results: The T&R procedure damps and improves infantile nystagmus syndrome (INS) waveforms, improves eXtended Nystagmus Acuity Function (NAFX) values, broadens the NAFX peak versus gaze angle, and damps slow eye movements but not saccades.

Infantile nystagmus syndrome: Broadening the high-foveation-quality field with contact lenses.

We investigated the effects of contact lenses in broadening and improving the high-foveation-quality field in a subject with infantile nystagmus syndrome (INS). A high-speed, digitized video system was used for the eye-movement recording. The subject was asked to fixate a far target at different horizontal gaze angles with contact lenses inserted.

Eye-movement-based assessment of visual function in patients with infantile nystagmus syndrome.

Purpose: Infantile Nystagmus Syndrome (INS) is an ocular motor system dysfunction characterized by the rhythmic to-and-fro oscillations of the eyes. Traditionally, the assessment of INS visual function solely focused on null- or primary-position visual acuity. Our purpose is to use the past four decades of INS research to introduce a more complete assessment of visual function in patients with INS.

Using the NAFX to measure the effectiveness over time of gene therapy in canine LCA.

Purpose: To use ocular motility recordings to determine the changes over time of infantile nystagmus syndrome (INS) in RPE65-deficient canines with Leber Congenital Amaurosis (LCA) and assess the time course of the recalibration of the ocular motor system (OMS).

Methods: Nine dogs were treated bilaterally with AAV-RPE65. A second cohort of four dogs was treated with AAV2.

Wavelet analysis in infantile nystagmus syndrome: limitations and abilities.

Purpose: To investigate the proper usage of wavelet analysis in infantile nystagmus syndrome (INS) and determine its limitations and abilities.

Methods: Data were analyzed from accurate eye-movement recordings of INS patients. Wavelet analysis was performed to examine the foveation characteristics, morphologic characteristics and time variation in different INS waveforms.