J Korean Ophthalmol Soc.  2016 Jun;57(6):957-962. 10.3341/jkos.2016.57.6.957.

Diagnostic Availability of Blind Spot Mapping for Ocular Torsion

• Lee JH
• Yum HR
• Lee SY
• Lee YC

• KMID: 2290499
• DOI: http://doi.org/10.3341/jkos.2016.57.6.957

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.

Keyword

Blind spot mapping; Fundus photograph; Ocular torsion

MeSH Terms

Humans
Optic Disk*
Strabismus
Visual Field Tests

Figure

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  Figure 1. 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.

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  Figure 2. 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).

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  Figure 3. 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.

Reference

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