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Combined gaze-angle and vergence variation in infantile nystagmus: two therapies that improve the high-visual-acuity field and methods to measure it.
Invest Ophthalmol Vis Sci. 2006 Jun; 47(6):2451-60.IO

Abstract

PURPOSE

To investigate the convergence-induced waveform and high-acuity-field improvements resulting from different therapies in two subjects with infantile nystagmus (IN) that was damped by convergence and to report a new finding in one of the subjects.

METHODS

Infrared reflection was used to measure eye movements during fixation of targets at different gaze and convergence angles and the expanded nystagmus acuity function (NAFX) to evaluate the IN waveform's foveation quality at all fixation points.

RESULTS

Recordings demonstrated that, at far, both subjects exhibited classic nulls (high NAFX values) with NAFX reduction at gaze angles lateral to the null. S1 was treated with prisms and S2 with surgery. When converged at near or at far with base-out prisms (S1) or after bimedial recession and bilateral tenotomy surgery (S2), NAFX was higher at both the null and lateral gaze angles; the null region was broadened. The longest foveation domain (gaze angles where the NAFX is within 10% of its peak) at near was three times wider than at far for S1 and two times wider after than before surgery for S2. The therapeutic improvement domain (gaze angles where the posttherapy NAFX is higher than pretherapy) was even broader. At fixed gaze angles in the central 20 degrees of gaze, S1's NAFX variation with vergence exhibited hysteresis, higher during divergence than convergence; S2 exhibited no hysteresis after surgery.

CONCLUSIONS

Damping IN by means of convergence, induced either surgically or with prisms, broadened the range of gaze angles with higher foveation quality, mimicking the null-broadening effects of tenotomy. The discovery of vergence hysteresis may reflect pulley movement and might allow higher acuity, if a near point is transiently fixated just before a far target. The acuity domains provide new and more comprehensive evaluations of both pre- and posttherapy visual function than do primary-position acuity measurements, suggesting that high-visual-acuity fields should be included in clinical measures of visual function in nystagmus.

Authors+Show Affiliations

Daroff-Dell'Osso Ocular Motility Laboratory, Louis Stokes Cleveland Veterans Affairs Medical Center, and Department of Neurology, Case Western University and University Hospitals of Cleveland, OH 44106, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

16723456

Citation

Serra, Alessandro, et al. "Combined Gaze-angle and Vergence Variation in Infantile Nystagmus: Two Therapies That Improve the High-visual-acuity Field and Methods to Measure It." Investigative Ophthalmology & Visual Science, vol. 47, no. 6, 2006, pp. 2451-60.
Serra A, Dell'Osso LF, Jacobs JB, et al. Combined gaze-angle and vergence variation in infantile nystagmus: two therapies that improve the high-visual-acuity field and methods to measure it. Invest Ophthalmol Vis Sci. 2006;47(6):2451-60.
Serra, A., Dell'Osso, L. F., Jacobs, J. B., & Burnstine, R. A. (2006). Combined gaze-angle and vergence variation in infantile nystagmus: two therapies that improve the high-visual-acuity field and methods to measure it. Investigative Ophthalmology & Visual Science, 47(6), 2451-60.
Serra A, et al. Combined Gaze-angle and Vergence Variation in Infantile Nystagmus: Two Therapies That Improve the High-visual-acuity Field and Methods to Measure It. Invest Ophthalmol Vis Sci. 2006;47(6):2451-60. PubMed PMID: 16723456.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Combined gaze-angle and vergence variation in infantile nystagmus: two therapies that improve the high-visual-acuity field and methods to measure it. AU - Serra,Alessandro, AU - Dell'Osso,Louis F, AU - Jacobs,Jonathan B, AU - Burnstine,Robert A, PY - 2006/5/26/pubmed PY - 2006/7/4/medline PY - 2006/5/26/entrez SP - 2451 EP - 60 JF - Investigative ophthalmology & visual science JO - Invest Ophthalmol Vis Sci VL - 47 IS - 6 N2 - PURPOSE: To investigate the convergence-induced waveform and high-acuity-field improvements resulting from different therapies in two subjects with infantile nystagmus (IN) that was damped by convergence and to report a new finding in one of the subjects. METHODS: Infrared reflection was used to measure eye movements during fixation of targets at different gaze and convergence angles and the expanded nystagmus acuity function (NAFX) to evaluate the IN waveform's foveation quality at all fixation points. RESULTS: Recordings demonstrated that, at far, both subjects exhibited classic nulls (high NAFX values) with NAFX reduction at gaze angles lateral to the null. S1 was treated with prisms and S2 with surgery. When converged at near or at far with base-out prisms (S1) or after bimedial recession and bilateral tenotomy surgery (S2), NAFX was higher at both the null and lateral gaze angles; the null region was broadened. The longest foveation domain (gaze angles where the NAFX is within 10% of its peak) at near was three times wider than at far for S1 and two times wider after than before surgery for S2. The therapeutic improvement domain (gaze angles where the posttherapy NAFX is higher than pretherapy) was even broader. At fixed gaze angles in the central 20 degrees of gaze, S1's NAFX variation with vergence exhibited hysteresis, higher during divergence than convergence; S2 exhibited no hysteresis after surgery. CONCLUSIONS: Damping IN by means of convergence, induced either surgically or with prisms, broadened the range of gaze angles with higher foveation quality, mimicking the null-broadening effects of tenotomy. The discovery of vergence hysteresis may reflect pulley movement and might allow higher acuity, if a near point is transiently fixated just before a far target. The acuity domains provide new and more comprehensive evaluations of both pre- and posttherapy visual function than do primary-position acuity measurements, suggesting that high-visual-acuity fields should be included in clinical measures of visual function in nystagmus. SN - 0146-0404 UR - https://www.unboundmedicine.com/medline/citation/16723456/Combined_gaze_angle_and_vergence_variation_in_infantile_nystagmus:_two_therapies_that_improve_the_high_visual_acuity_field_and_methods_to_measure_it_ L2 - https://iovs.arvojournals.org/article.aspx?doi=10.1167/iovs.05-1320 DB - PRIME DP - Unbound Medicine ER -