자기공명영상을 이용한 안와각과 안운동각의 측정

Abstract

[한글]

사시수술 방법중 가장 많이 시행되는 방법의 하나인 외안근 후전술을 시행할 때, 안운동적도 뒤쪽으로 외안근을 후전할 경우 그 근육의 작용방향으로 안구운동의 제한을 일으킬 수 있다. 안구운동의 제한을 일으키지 않는 ‘안전한 후전의 한계’인 안운동적도의

위치는 안구의 크기와 안운동각의 크기에 의해서 결정되며, 안운동각은 안와의 크기 또는 안와각에 따라 영향을 받을 것으로 생각하여 본 저자는 안전한 후전의 한계를 알아보고자 자기공명영상을 이용하여 정상 150안에서 안구와 안와의 여러 계측치를 측정, 비교하

여 다음과 같은 결론을 얻었다.

1. 안와각은 평균 42.4도였고 남자 41.9도, 여자 43.0도로 여자에서 컸으며 연령에 따른 유의한 차이는 없었다.

2. 안운동각은 평균 12.1도였고 성별이나 연령에 따른 유의한 차이는 없었다.

3. 안와각은 안운동각, 그리고 해부학적 적도로부터 안운동적도까지의 거리와 통계적으로 유의한 상관관계가 있었다. 즉 안와각이 커질수록 안운동각이 커졌고, 안운동적도는 해부학적 적도로부터 멀어졌다.

4. 안운동적도는 해부학적 적도로부터 내직근쪽은 전방으로, 외직근쪽은 후방으로 평균 2.53 mm 전위되어 있었으며 성별이나 연령에 따른 유의한 차이는 없었다.

5. 평균의 안구직경에서 안전한 후전량은 내직근 4.8 mm, 외직근 8.7mm였다.

이상의 결과를 종합해 볼 때 사시수술을 함에 있어 외안근 후전의 안전한 한계를 정하는 요인의 하나인 안운동각은 연령, 성별에 따른 차이가 없으며, 후전의 한계는 안구의 직경을 고려하여 정할 수 있을 것으로 생각된다.

Determination of oculomotor and orbital angles using the magnetic resonance imaging

Hye Young Kim

Department of medical science The Graduate School, Yonsei University

(Directed by Associate Professor Jong Bok Lee)

In the course of the recession of extraocular muscles, one of the most commonly

employed methods in squint surgery, the eyeball movements could be restricted if

the muscles are recessed behind the oculomotor equator. The position of oculomotor

equator, which is the 'safe limit' of the recession, is determined by both the

diameter of eyeball and the size of the oculomotor angle, and the latter, in turn,

appears to be influenced by the size of orbit or orbital angle. In the present

study, several measurements were made concerning eyeball and orbit in 150 normal

eyes using the magnetic resonance imaging. The results are as follows :

1. The average of orbital angles was 42.4 , those of females(43.0 ) being

significantly larger than those of males(41.9 ). There was no significant

difference in orbital angle among different age groups.

2. The average of oculomotor angles was 12.1 , and there was no significant

difference among different sex or age groups.

3. As the increment of orbital angle, the oculomotor angle and the distance

between the oculomotor and the anatomical equator were significantly increased.

4. The average distance between the oculomotor and the anatomical equators was

2.53 mm. There was no significant difference among different sex or age groups.

5. The safe limits of the recession were 4.8 mm for the medial rectus muscle and

8.7 mm for the lateral rectus muscle to the eyeball of average diameter.

These results suggest that the safe limit of the recession could be determined by

a single factor, the diameter of eyeball, since the oculomotor angles do not show

significant difference among different sex or age groups.

[영문]

In the course of the recession of extraocular muscles, one of the most commonly employed methods in squint surgery, the eyeball movements could be restricted if the muscles are recessed behind the oculomotor equator. The position of oculomotor equator, which is the 'safe limit' of the recession, is determined by both the

diameter of eyeball and the size of the oculomotor angle, and the latter, in turn, appears to be influenced by the size of orbit or orbital angle. In the present study, several measurements were made concerning eyeball and orbit in 150 normal eyes using the magnetic resonance imaging. The results are as follows :

1. The average of orbital angles was 42.4 , those of females(43.0 ) being significantly larger than those of males(41.9 ). There was no significant difference in orbital angle among different age groups.

2. The average of oculomotor angles was 12.1 , and there was no significant difference among different sex or age groups.

3. As the increment of orbital angle, the oculomotor angle and the distance between the oculomotor and the anatomical equator were significantly increased.

4. The average distance between the oculomotor and the anatomical equators was 2.53 mm. There was no significant difference among different sex or age groups.

5. The safe limits of the recession were 4.8 mm for the medial rectus muscle and 8.7 mm for the lateral rectus muscle to the eyeball of average diameter.

These results suggest that the safe limit of the recession could be determined by a single factor, the diameter of eyeball, since the oculomotor angles do not show significant difference among different sex or age groups.