JKOS Journal of the Korean Ophthalmological Society J Korean Ophthalmol Soc 0378-6471 2092-9374 Korean Ophthalmological Society 10.3341/jkos.2016.57.6.957 jkos-57-957 Original Article Diagnostic Availability of Blind Spot Mapping for Ocular Torsion LeeJae Hoon MD 1 YumHae Ri MD 2 LeeSe Youp MD, PhD 3 LeeYoung Chun MD, PhD 1 Department of Ophthalmology and Visual Science, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea Department of Ophthalmology, Konyang University College of Medicine, Daejeon, Korea Department of Ophthalmology, Keimyung University School of Medicine, Daegu, Korea Address reprint requests to Young Chun Lee, MD, PhD Department of Ophthalmology, The Catholic University of Korea Uijeongbu St. Mary's Hospital, #271 Cheonbo-ro, Uijeongbu 11765, Korea Tel: 82-31-820-3022, Fax: 82-31-847-3418 E-mail: yclee@cmcnu.or.kr 09 2016 25 09 2016 576 957 962 23072015 31012016 14042016 Copyright © 2016 Korean Ophthalmological Society 2016 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Purpose

To evaluate diagnostic the usefulness of blind spot mapping in measuring ocular torsion changes and to investigate the correlations of inferior oblique muscle overaction (IOOA) and excyclotorsion measurements using fundus photographs and blind spot mapping in patients with secondary IOOA.

 Methods

Eleven patients (12 eyes; IOOA group) diagnosed with secondary IOOA were evaluated for ocular movement, fundus photograph and Humphrey standard automated perimetry, and 10 patients (20 eyes; control group) were subjected to the same tests. An ocular movement examination was performed to evaluate IOOA, and fundus photograph and Humphrey standard automated perimetry were used to measure the ocular torsion. Inferior oblique myectomy or recession was performed along with horizontal strabismus surgery, and preoperative and postoperative IOOA and ocular torsion measurements were compared between the groups.

 Results

In the IOOA group after surgery, the IOOA decreased from +2.42 ± 0.63 to +0.50 ± 0.52, the ocular torsion decreased from +14.15 ± 3.60° to +7.47 ± 1.65° (p < 0.001) on fundus photographs, and from +12.19 ± 1.62° to +9.69 ± 1.75° (p = 0.061) in Humphrey standard automated perimetry. The control group showed a mean ocular torsion of 7.44 ± 1.62° on fundus photographs and +7.24 ± 1.28° on Humphrey standard automated perimetry.

 Conclusions

The usefulness of blind spot mapping when the ocular torsion was measured in IOOA patients was considered low, due to the weak correlation between IOOA and extorsion; preoperative and postoperative ocular torsion amount values were not significantly different.

 Blind spot mapping Fundus photograph Ocular torsion References Knapp P Vertically incomitant horizontal strabismus: the so-called “A” and “V” syndromes Trans Am Ophthalmol Soc 1959 5766699 Bixenman WW von Noorden GK Apparent foveal displacement in normal subjects and in cyclotropia Ophthalmology 1982 895862 Locke JC Heterotopia of the blind spot in ocular vertical muscle imbalance Am J Ophthalmol 1968 6536274 Morton GV Lucchese N Kushner BJ The role of funduscopy and fundus photography in strabismus diagnosis Ophthalmology 1983 90118691 Lee HJ Lim KH The range of ocular torsion in mass screening J Korean Ophthalmol Soc 2005 4616849 Versino M Newman-Toker DE Blind spot heterotopia by abdominal static perimetry to assess static ocular torsion: centro-cecal axis rotation in normals J Neurol 2010 2572913 Von Noorden GK Campos EC Binocular Vision and Ocular Motility: Theory and Management of Strabismus 6th ed. St Louis St Louis 2002 556 Rosenbaum AL Santiago AP Clinical Strabismus Management 1st ed. Philadelphia Philadelphia 1999 559 Kim EH Lee SJ Choi HY Ocular torsion according to fixation in fundus photograph J Korean Ophthalmol Soc 2006 4744954 Guyton DL Clinical assessment of ocular torsion Am Orthopt J 1983 3385 Eustis HS Nussdorf JD Inferior oblique overaction in infantile esotropia: fundus extorsion as a predictive sign J Pediatr Ophthalmol Strabismus 1996 33858 Cho HH Sohn MA The ocular cyclotorsion induced by the abdominalal change J Korean Ophthalmol Soc 1999 4029117 Yim JH Min BM Xu YG Surgical results of classic Harada-Ito procedure with intraoperative adjustment for excyclotorsion J Korean Ophthalmol Soc 2002 43222733 Sim JH Lee SY The effect of inferior oblique weakening abdominal on the correction of ocular torsion J Korean Ophthalmol Soc 2005 4610206 Lee DH Lee SJ Park SH Ocular torsion in normal Korean population J Korean Ophthalmol Soc 2004 45797802 Park SW The torsional status of normal Koreans J Korean Ophthalmol Soc 2004 45190611 Ramat S Nesti A Versino M A new device to assess static ocular torsion Ann N Y Acad Sci 2011 123322630 Figures and Tables

Determination of the optic disc center. We drew two horizontal lines at the superior and inferior borders of the optic disc and two vertical lines at the temporal and nasal borders. Next, we drew the central lines that pass through the middle of the horizontal and vertical lines. We set the optic disc center at the point where the two center lines cross each other. θ = tan−1(b/a); a = horizontal optic disc center-foveal distance; b = vertical optic disc center-foveal distance.

A construction example of the centro-cecal axis for the purpose of centro-cecal axis rotation (CCAR) torsion measurement from the visual field chart. A straight line was drawn connecting the center of the blind spot to the fixation point. Next, we measured the CCAR manually (using a mag-nifying lens and protractor).

The correlation between the inferior oblique overaction and extorsion by the fundus photograph and blind spot mapping. (A) Based on fundus photograph, a statistically significant positive correlation was found between the inferior oblique overaction and extorsion. (B) Based on blind spot mapping, a weak positive correlation was observed between the inferior oblique overaction and extorsion, but without statistical significance.

Demographic data of patients

  Patient group Control group
Number of patients 11 10
Number of eyes 12 20
Average age (years) 21.4 ± 3.60 24.4 ± 2.87
Sex (n, %)    
 Male 6 (54.5) 6 (60)
 Female 5 (45.5) 4 (40)
Unilateral IOOA (n, %) 11 (100) 0 (0)
Associated strabismus (n, %)    
 Exotropia 4 (36.4) 0 (0)
 IOOA only 7 (63.6) 0 (0)

Values are presented as number (%) or mean ± SD.

IOOA = inferior oblique overaction.

Comparison of preoperative and postoperative IOOA and extorsion

  IOOA
 Fundus photography
 Blind spot mapping
  Preop Postop p-value Preop Postop p-value Preop Postop p-value
Patient                  
 OP eye + 2.42 ± 0.63 +0.50 ± 0.52 p<0.001 +14.15 ± 3.60° +7.47 ± 1.65° p<0.001 +12.19 ± 1.62° +9.69 ± 1.75° p=0.061
 TOE <1 <1   +7.07 ± 1.21° +6.16 ± 2.31° p=0.193 +8.01 ± 1.32° +7.72 ± 1.44° p=0.723
Control <1 <1   +7.44 ± 1.62°   p<0.001 +7.24 ± 0.32°   p=0.048

Values are presented as mean ± SD unless otherwise indicated.

IOOA = inferior oblique overaction; Preop = preoperative state; Postop = postoperative state; OP = operation; TOE = the other eye.