Optical Coherence Tomography Angiography: Are There Any Changes in Measurements After Strabismus Surgery?

Investigation of the effects of single and two-muscle horizontal rectus surgeries on macular microvasculature

PURPOSE

To investigate the changes in posterior segment hemodynamics caused by horizontal rectus muscle surgeries using the optic coherence tomography angiography (OCTA).

METHODS

Patients who underwent at least one horizontal rectus recession, resection, or combination surgery were included. The patients were evaluated with an OCTA preoperatively and 30 days postoperatively. Postoperative changes in superficial capillary plexus (SCP)-vessel density (VD), deep capillary plexus (DCP)-VD, foveal avascular zone (FAZ) area and choriocapillaris (CC)-flow area parameters were examined. The mean differences (Δ) for the parameters in which significant changes were detected in the whole operated eyes group were compared between the single- and two-muscle surgery groups.

RESULTS

Twenty-five eyes of 24 patients with an average age of 16.40 ± 6.75 years (5-29) were included. Of the eyes, 10 underwent single muscle recession surgery. Two-muscle surgeries were performed in 15 eyes. SCP-VD in the superior parafoveal region increased significantly postoperatively (53.23 ± 4.11% vs. 54.54 ± 3.67%, p = 0.032). For DCP-VD, there was a statistically significant increase in all zones, except the superior hemisphere and fovea regions (p < 0.05 for all). FAZ area did not change significantly (p = 0.207). There was a significant increase in the CC-flow area (2.171 ± 0.146 mm2 vs. 2.232 ± 0.115 mm2, p = 0.013). There was a significant difference between the two groups only for the Δ SCP-VD/parafovea superior value (-0.62 ± 0.98 vs. 1.57 ± 3.07, p = 0.019).

CONCLUSIONS

Conventional horizontal rectus muscle surgeries may cause alterations in posterior segment hemodynamics. The number of muscles incised does not seem to greatly affect the magnitude of changes that occur.

KEY MESSAGES

What is known • After conventional horizontal rectus muscle surgeries, the anterior ciliary arteries are not recanalized, instead, anterior segment blood flow is maintained by increasing the flow in the long posterior ciliary arteries. • Previous studies using Doppler ultrasonography have shown increased flow in the ophthalmic artery, central retinal artery and long posterior ciliary arteries. What is new • In this study, significant increases were observed in superficial and deep capillary plexus-vessel density and choriocapillaris-flow area parameters in the first postoperative month with optic coherence tomography angiography device. • Hemodynamic increases in both retinal and choroidal vasculature were detected in the early period after conventional horizontal rectus muscle surgeries. • The number of muscles incised does not seem to greatly affect the magnitude of changes that occur.

Evaluation of Macular Neurovasculature and Choroidal Blood Flow Following Inferior Oblique Myectomy Using Optical Coherence Tomography Angiography

PURPOSE

To evaluate the short-term effects of inferior oblique myectomy on the retinal neurovasculature, choroidal thickness, and choroidal vascularity index at the macula.

METHODS

Patients older than 5 years who were candidates for inferior oblique muscle myectomy surgery participated in the study. Patients with any systemic or ocular disease that could affect the macular neurovasculature were not included in the study. After recording demographic data, including age and gender, and conducting a complete ophthalmic examination, macular optical coherence tomography (OCT), enhanced depth imaging OCT, and OCT angiography imaging (AngioVue software (V.2017.1.0.151; Optovue, Inc) were performed before (1 day to 1 week) and in the specific time intervals (1 week, 1 month, and 3 months) after the surgery for all participants.

RESULTS

Eighteen patients (13 male and 5 female) who underwent inferior oblique muscle myectomy, with a mean ± standard deviation age of 24.22 ± 18.14 years, were included in this study. The baseline mean ± standard deviation of subfoveal choroidal luminal area and subfoveal total choroidal area were 0.390 ± 0.03 and 0.539 ± 0.04 mm2, respectively. The changing pattern of the subfoveal choroidal vascularity index and subfoveal choroidal luminal area was statistically significant (P = .013 and .035, respectively).

CONCLUSIONS

Inferior oblique myectomy can lead to changes in choroid hemodynamics in the short term. However, these changes seem to be temporary. [J Pediatr Ophthalmol Strabismus. 2024;61(4):235-244.].

Optical Coherence Tomography Angiography Evaluation of Retinal and Choroidal Microvascular Morphological Changes Following Strabismus Surgery

PURPOSE

To evaluate the structural and microvascular changes in the retina and choroid after strabismus surgery.

METHODS

The study included 44 eyes from 44 patients who underwent strabismus surgery between August 2020 and December 2021. Among these patients, 9 (20%) underwent horizontal one-muscle surgery, 27 (61%) underwent horizontal two-muscle surgery, and 8 (18%) underwent inferior oblique muscle anteriorization surgery. Optical coherence tomography angiography scans were conducted preoperatively and at 1 day, 1 week, 1 month, and 3 months postoperatively.

RESULTS

The outer retinal blood flow showed a significant increase at 1 day postoperatively in horizontal two-muscle and inferior oblique muscle anteriorization surgery, whereas no significant difference was observed between periods in horizontal one-muscle surgery (P = .007). Choriocapillaris blood flow exhibited a significant increase at 1 day and 1 month postoperatively compared to the preoperative period (P < .001). Whole image superficial capillary plexus vascular density was significantly lower at 1 day postoperatively than preoperatively and 1 and 3 months postoperatively (P < .001). Whole image deep capillary plexus vascular density was significantly lower at 1 day than at 1 month postoperatively (P = .002).

CONCLUSIONS

Following strabismus surgery, temporary changes in the hemodynamic microcirculation in the retina and choroid are observed. A transient decrease in retinal artery blood supply may be noticed, possibly attributed to the reduced anterior segment blood supply. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].

Assessment of retinal and choroidal microcirculation after unilateral recession-resection surgery for horizontal strabismus by swept-source optical coherence tomography angiography

This study explored the possible hemodynamic changes of the retina and choroid after horizontal strabismus surgery using swept-source optical coherence tomography angiography (SS-OCTA). 32 eyes of 32 patients who underwent unilateral horizontal rectus muscle recession-resection surgery were included. SS-OCTA examinations were performed preoperatively and one week postoperatively. Several OCTA measurements were used, including vessel density (VD) of the superficial vascular complex (SVC), VD of the deep vascular complex (DVC), VD of the choriocapillaris (CC), choroidal vascular index (CVI) and choroidal thickness (CT). No significant change in VD of SVC, DVC, and CC was observed whereas CT increased significantly with CVI unchanged. Recession-resection surgery for horizontal strabismus seemed not to significantly influence the microcirculation of the retina and CC in the early postoperative period. However, choroidal thickening happened with a constant CVI probably due to the postoperative inflammation. Further studies are needed to investigate the long-term effects of unilateral recession-resection surgery for horizontal strabismus on the microcirculation of the retina and choroid.

Changes in retinal and choroidal blood flow after one or two horizontal rectus muscle surgeries by optical coherence tomography angiography

PURPOSE

To evaluate the retinal and choroidal microvasculature after one or two horizontal rectus muscle surgeries in strabismus patients using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

30 eyes of 26 patients who underwent horizontal rectus muscle surgery were included in this study. Group A, A' and Group B , B' respectively consisted preoperative and postoperative measurements of patients who underwent one or two horizontal rectus muscle surgeries. We analyzed the vessel density (VD) of the superficial vascular complex (SVC), the deep vascular complex (DVC), the choriocapillary layer (CC), choroidal vascular index (CVI), choroidal thickness (T-Ch) and retinal nerve fiber layer thickness (T-RNFL) preoperatively, and one week postoperatively.

RESULTS

Only in the nasal sector of the perifoveal zone, the VD in SVC demonstrated a significant increase in Group A' (p = 0.027). There was a statistically significant difference in the VD changes of SVC between Group A and Group B (p = 0.043). The VD in DVC did not change significantly in the whole macular compared with the preoperative. Moreover, in both Group A' and Group B', the VD in CC showed a reduction in a single sector of the parafoveal area (p < 0.05). Group A' have increased CVI in the nasal sector of the perifoveal region (p = 0.008). In addition, the T-Ch increase in the perifoveal region was more significant in Group B' than in Group A' (p < 0.05). Group A' showed statistically significant decreases in T-RNFL in the foveal and parafoveal regions (p < 0.05).

CONCLUSION

This study revealed that the increase in choroidal thickness was more significant after two rectus muscle surgery. In addition, there were microvascular changes in sectional macular regions after strabismus surgery. OCTA is an excellent way to study the impact of strabismus surgery on the macular structure and blood flow.

Evaluation of retinal microvasculature in exotropia with abnormal binocular vision by optical coherence tomography angiography

BACKGROUND

To explore the retinal microvasculature in large-angle concomitant exotropia patients with abnormal binocular vision using optical coherence tomography angiography (OCTA) analysis.

METHODS

OCTA images of 52 healthy and 100 strabismic eyes were analyzed to quantify the retinal thickness (RT), superficial capillary plexus (SCP), deep capillary plexus (DCP), and foveal avascular zone (FAZ). Paired t-tests were performed to compare differences between the two groups, the dominant eye and the deviated eye in the exotropia group, respectively. A p-value < 0.01 was considered significant.

RESULTS

The mean angle of deviation was 79.38 [± 25.64] (prism diopters, PD). There were significant differences in the DCP in deviated eyes between the exotropia group and the control group (fovea: p = 0.007; temporal: p = 0.014; nasal: p = 0.028; inferior: p = 0.013). The temporal SCP in the exotropia group was significantly higher than in the control group in deviated eyes (p = 0.020). No significant difference was found between dominant eyes and strabismic eyes (p > 0.01).

CONCLUSIONS

The study showed that OCTA revealed subnormal DCP in patients with large-angle exotropia and abnormal binocularity which may be related to retinal suppression. Changes in the macular microvasculature may provide valuable insights into the development of strabismus. Further studies are needed to determine the clinical relevance of this finding.

TRIAL REGISTRATION

This trial is registered as ChiCTR2100052577 at www.Chictr.org.cn .

Retinal and choroidal microvasculature is altered after strabismus surgery

PURPOSE

To evaluate the retinal and choroidal microvasculature after strabismus surgery using swept-source optical coherence tomography angiography (OCTA).

METHODS

Thirty-three eyes of 33 patients who underwent horizontal rectus surgery for strabismus were included in this retrospective study. The unoperated fellow eyes were used as the control group. The macular microvasculature was assessed using a 3 × 3 scan pattern centred on the fovea preoperatively, and one week and one month postoperatively. The vessel density (VD) of superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) were automatically analyzed. The foveal avascular zone (FAZ) was calculated manually using the tool of the device.

RESULTS

The VD in SCP demonstrated a significant difference between operated and fellow eyes at one week (p = 0.017). Moreover, a significant increase was observed in the mean VD values in SCP of operated eyes after surgery (p = 0.037). The VD in DCP exhibited no significant differences between operated and fellow eyes before and after strabismus surgery. However, there was a significant difference in VD was observed between operated and fellow eyes one week after surgery (p = 0.001). The mean VD in CC was significantly increased in the operated eyes one week after surgery compared to preoperative values (p = 0.006).

CONCLUSION

This study revealed that strabismus surgery may cause transient alterations both in retinal and choroidal microcirculation in the early postoperative period.

Evaluation of macular vessel density changes after strabismus surgery using optical coherence tomography angiography

PURPOSE

To compare retinal vessel density before and after strabismus surgery using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

In this longitudinal, single-arm pilot study, vascular density in the deep capillary plexus (DCP), superficial retinal capillary plexus (SCP) and choriocapillaris layer (CCL) in consecutive subjects undergoing strabismus surgery was assessed using SS-OCTA preoperatively (T0), on the first day postoperatively (POD1), and 30 days postoperatively (POD30).

RESULTS

A total of 92 eyes of 56 patients (54% males) were included. Mean patient age was 41.1 ± 22.7. OCT vascular density of the DCP was 50.20 ± 5.57 at T0, 52.74 ± 4.77 at POD1, and 50.92 ± 4.58 at POD30. The differences were statistically significant for T0 versus POD1 (P < 0.05). Vascular density of the CCL was 50.72 ± 4.80 at T0, 53.59 ± 3.65 at POD1, and 51.39 ± 4.64 at POD30. The differences were statistically significant for T0 versus POD1 (P < 0.05). No significant differences were found in SCP (P > 0.05).

CONCLUSIONS

Transitory hemodynamic changes can occur in the DCP and in the CCL following muscle recession procedures.

Comparison of quantitative measurement of macular vessel density before and after inferior oblique muscle-weakening surgery: An optical coherence tomography angiography study

PURPOSE

To investigate hemodynamic changes in retinal and choroidal vasculature after surgical inferior oblique (IO) weakening through optical coherence tomography angiography (OCTA).

METHODS

The medical records of patients who underwent unilateral IO-weakening surgery at a single institution were retrospectively reviewed. Patients who had OCTA measurements before surgery and on postoperative days 7 and 30 were included. Vessel density was determined for the superficial capillary plexus (SCP), deep capillary plexus (DCP), the choriocapillaris (CCP) and the foveal avascular zone (FAZ).

RESULTS

The study included 72 eyes of 36 patients. Fellow eyes were used as a control group. The preoperative and postoperative week 1 and month 1 mean central vessel densities of the SCP were 20.48% ± 3.52%, 20.68% ± 3.83%, and 23.56% ± 5.65%, respectively, in the operated eye; those of the DCP were 16.72% ± 3.33%, 16.08% ± 4.65%, and 20.85% ± 7.09%, respectively. The mean FAZ areas were 341.29 ± 88.04 μm², 341.30 ± 98.25 μm², and 316.02 ± 74.61 μm², respectively. We detected no significant changes in SCP, DCP, and FAZ in the postoperative period. The mean central vessel density of the CCP increased significantly from the preoperative level of 54.06% ± 2.86% to 55.55% ± 2.63% at postoperative week 1, but there was no significant difference between baseline and postoperative month 1 (P = 0.001 and P = 0.515, resp.).

CONCLUSIONS

IO muscle surgery does not seem to cause alterations in retinal hemodynamics, although it can transiently increase the central vessel density of the CCP during the early postoperative period.

Macular perfusion density evaluation in constant and intermittent exotropia by means of optical coherence tomography angiography

Background

To quantify and compare retinal microvascular features using optical coherence tomography angiography (OCTA) in constant (XT) and intermittent exotropia (IXT).

Methods

An observational cross-sectional study was conducted from September 2020 to November 2020 at the Affiliated Eye Hospital of Wenzhou Medical University. OCTA examination was performed to evaluate the macular perfusion density of the deep capillary plexus (DCP), superficial capillary plexus (SCP), and foveal avascular zone (FAZ) parameters in XT and IXT patients, and in age-matched controls. The study parameters were analyzed.

Results

A total of 76 participants, including 16 (21%) XT patients, 24 (32%) IXT patients, and 36 (47%) controls, were recruited. The exodeviation angle was 39.06 ± 10.38 prism degrees (PD) at near and 43.00 ± 9.74 PD at distance in the XT group, and 27.13 ± 18.28 PD at near and 31.04 ± 18.82 PD at distance in the IXT group. The macular perfusion density of the DCP in 6 × 6-mm scans and the SCP in 3 × 3-mm scans were lower in the deviating eyes than in the fixating eyes of XT patients (p < 0.001, p = 0.032, respectively). The macular perfusion density of the DCP in the deviating eyes of XT and IXT patients was significantly lower than that of the controls. There was no significant difference in the FAZ parameters among the groups.

Conclusions

In XT patients, OCTA revealed lower macular perfusion density in deviating eyes than in fixating eyes and control eyes. IXT patients showed no difference between the two eyes, but the macular perfusion density of the DCP was lower than that of the controls.

Comparison of Pre-Treatment vs. Post-Treatment Retinal Vessel Density in Children with Amblyopia

BACKGROUND

Prior studies have reported a lower retinal vessel density (RVD) in amblyopic vs. non-amblyopic eyes. No studies have shown if amblyopic eye RVD changes following patching therapy. We assessed for RVD differences between pre-treatment vs. post-treatment amblyopic eyes.

METHODS

Participants were included if they were <10 years old with unilateral amblyopia. All subjects were required to visit the pediatric eye clinic for examination. Exclusion criteria included: deprivation amblyopia, bilateral amblyopia, nystagmus, media opacity, intraocular inflammation, or any retinal disease. All participants underwent optical coherence tomography angiography (OCTA) before and after refraction and patching treatment. Outcomes included superficial (SCP) and deep (DCP) capillary plexus RVD.

RESULTS

12 patients (12 amblyopic eyes) were included. Mean (SD) age, gestational age (GA), birth weight (BW), and follow-up time were: 6.5 (1.7) years, 39.4 weeks (1.4 w), 3271 g (262 g), and 114 days (46d), respectively. There was a significant increase in the RVD of the DCP in 3 × 3-mm scans after treatment, specifically in the whole image (52.6 ± 5.75 vs 56.5 ± 2.48%, p = .046) and superior hemisphere regions (52.47 ± 6.17 vs 56.73 ± 2.27%, p = .048).

CONCLUSIONS

Amblyopic eye RVD potentially increases after amblyopia treatment in specific regions of the retina. Further research is required to refine this clinical parameter.