Application of indocyanine green iris angiography in the evaluation of anterior segment blood supply in different strabismus patients

Abstract

Objective: To evaluate the perfusion features of the anterior segment in patients with different types of strabismus. Methods: A cross-sectional study. Sixteen strabismus patients (16 eyes) who received the examination of iris indocyanine green angiography (ICGA) in Tianjin Eye Hospital from November 2016 to December 2021 were enrolled and divided into two groups according to whether they had a history of extraocular muscle injury/rectus muscle surgery. All patients underwent routine ophthalmic examinations. Angiographic images were obtained by the anterior segment camera, and indicators such as arm to iris circulation time, whole iris filling time, regression onset time, and complete regression time were recorded. The independent sample t test or Mann-Whitney U test was used to compare iris perfusion aspects of the two groups, and the Pearson/Spearman correlation tests was used to analyze the correlation of arm to iris circulation time and whole iris filling time with age and course of strabismus. Results: Among the 16 patients, there were 10 males and 6 females. The mean age was (49.2±13.2) years, and the course of strabismus ranged from 2 to 31 months. There were 7 patients in the group of without extraocualr muscle injury and 9 patients in the extraocular muscle injury/surgery group. There was no significant difference in age and course of strabismus between the two groups (both P>0.05). The arm to iris circulation time [M (Q1, Q3)] of the group without extraocular muscle injury and the group with extraocular muscle injury/surgery were 18 (18, 21) and 22 (20, 24) s, respectively. The average whole iris filling time was (13.86±1.95) and (12.22±3.60) s, respectively. There was no statistical significance between the two groups (both P>0.05). Correlation analysis showed that arm to iris circulation time was not correlated with age and course of strabismus (r=-0.033, -0.079; both P>0.05). And the whole iris filling time was not correlated with age and course of disease (r=0.057, -0.119; both P>0.05). The matrix scatter plots showed that in the group of extraocular muscle injury/surgery, there were three patients who were older than the average (49.2 years) and above the median of arm to iris circulation time (20 s) (two cases with the vertical muscle involved), meanwhile, there were three patients (all with the vertical muscle involved) whose course of strabismus was longer than 6 months and above the median of arm to iris circulation time, which were more than those in the group of without extraocular muscle injury (1 case, respectively). Conclusions: ICGA in patients with strabismus show that a history of injury to the extraocular muscle or surgical treatment beyond 2 months had no effect on iris perfusion. Age and course have no correlation with iris reperfusion. The vertical muscle involvement has more effects on the blood supply to the anterior segment.