Macular Thickness Following Strabismus Surgery as Determined by Optical Coherence Tomography

Short-Term Morpho-Functional Changes before and after Strabismus Surgery in Children Using Structural Optical Coherence Tomography: A Pilot Study

PURPOSE

To evaluate the immediate alterations in the thickness of the macular ganglion cell-inner plexiform layer (mGCIPL), peripapillary retinal nerve fiber layer (RNFL), inner retinal layer (IRL), and outer retinal layer (ORL) using spectral domain optical coherence tomography (SD-OCT) subsequent to strabismus surgery in pediatric patients diagnosed with horizontal esotropia.

METHODS

Twenty-eight eyes from twenty-one child patients who had undergone uncomplicated horizontal rectus muscle surgery due to strabismus were included. Measurements of RNFL, mGCL-IPL, IRL, and ORL using structural OCT were conducted both before the surgery and one month after the surgical procedure. Importantly, a control group comprising 14 healthy eyes, matched for age and significant refractive error (<3.00 diopters), was included in the current analysis.

RESULTS

Our analysis indicated no significant disparity before and after surgery in terms of best-corrected visual acuity (BCVA), RNFL, IRL, and ORL. Conversely, concerning the macular ganglion cell layer-inner plexiform layer analysis, a substantial increase in mGCL-IPL was observed following the surgical intervention. The mean mGCL-IPL measured 60.8 ± 9.2 μm at baseline and 66.1 ± 13.2 μm one month after the surgery (p = 0.026). Notably, comparison between the strabismus group at baseline and the healthy group revealed a significant reduction in mGCL-IPL in the strabismus group (60.8 ± 9.2) compared to the healthy control group (68.3 ± 7.2; p = 0.014).

CONCLUSIONS

Following strabismus surgery, our observations pointed towards a thickening of the mGCL-IPL layer, which is likely attributable to transient local inflammation. Additionally, we identified a significant differentiation in the mGCL-IPL complex between the pediatric patient group with strabismus and the control group.

Short-term Effect of Strabismus Surgery on Choroidal Vasculature

PURPOSE

To investigate the effect of strabismus surgery on choroidal structure using the binarization method.

METHODS

Forty-two eyes of 27 patients who had surgery for horizontal strabismus were included in the study. Optical coherence tomography (OCT) images of the patients before the operation and at 1 day and 1 week after the operation were binarized. Total choroidal area (TCA), stromal area (SA), luminal area (LA), and choroidal vascularity index (CVI) were calculated and compared.

RESULTS

The mean age of the patients was 16.7 ± 13.5 years; 12 were female, and 15 were male. The mean spherical equivalent was 0.125 ± 0.50 diopters (D). The mean axial length value was 23.3 ± 1.3 mm. Preoperative TCA was 599686 ± 113451, LA was 394259 ± 67259, SA was 209180 ± 47723, and CVI was 0.66 ± 0.02. At 1 day postoperatively, TCA was 615575 ± 103686, LA was 395364 ± 60314, SA was 218418 ± 45620, and CVI was 0.65 ± 0.02. At 1 week postoperatively, TCA was 610997 ± 110578, LA was 394002 ± 65186, SA was 214995 ± 46481, and CVI was 0.66 ± 0.04. A statistically significant decrease in CVI and increase in TCA and SA were observed on the first postoperative day; these changes were observed as returning to preoperative values at 1 week postoperatively.

CONCLUSIONS

Strabismus surgery temporarily decreases the CVI by increasing the SA of the choroidal layer, possibly due to hemodynamic changes and/or inflammatory causes in the early period. [J Pediatr Ophthalmol Strabismus. 2024;61(2):114-119.].

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 .

Effect of inferior oblique muscle myomectomy on choroidal and macular thicknesses in strabismus

BACKGROUND

In this study, we aimed to determine postoperative changes in macular and choroidal thicknesses in patients who underwent inferior oblique myomectomy.

METHODS

The study included 54 eyes of 44 patients who underwent inferior oblique muscle myectomy between January 2018 and April 2022. Visual acuity and macular and choroidal thickness measurements were performed preoperatively and postoperatively (day 1, week 1, month 1, and month 3).

RESULTS

When the choroidal thickness measurements were examined, it was determined that choroidal thicknesses decreased especially in the nasal and subfoveal regions on the first day and at the first week after surgery (p < 0.05) but approached their preoperative values ​​at the first- and third-month evaluations (p > 0.05). The macular thickness measurements revealed an increase in all macular regions on the first day and at the end of the first week (p < 0.05) and approached their preoperative values ​​at the end of the first and third months (p > 0.05).

CONCLUSIONS

In this study, although choroidal thicknesses decreased in the early postoperative period in patients who had undergone inferior oblique myomectomy, there was an increase in macular thicknesses. However, at the third postoperative month, choroid and macular thicknesses were found to be similar to the preoperative values​.

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.

Influence of one or two horizontal muscle surgeries on OCT findings

We investigate the effects of differences between one or two horizontal rectus muscle surgeries (recession ± resection) on the central macular thickness (CMT), subfoveal choroidal thickness (SFCT), and retinal nerve fiber layer (RNFL). Measurements of the CMT, SFCT, and RNFL in patients who underwent horizontal rectus muscle surgery were obtained using optical coherence tomography (OCT). Patients were grouped as those who had undergone rectus muscle recession surgery (Group 1) and those who had undergone rectus muscle recession + resection surgery (Group 2). The CMT, SFCT, and RNFL in patients were measured preoperatively and 1 day, 1 week, 1 month, 3 months, and 6 months postoperatively. A total of 65 eyes of 50 patients were analyzed retrospectively. The average age of the 25 patients in Group 1 was 8.96 ± 7.966 years (min 3, max 38). The average age of the 25 patients in Group 2 was 15.17 ± 6.806 years (min 2, max 34). The comparison of the preoperative and the 1-day and 1-week postoperative values revealed an increase in CMT and SFCT in Group 1 and Group 2. There were no significant differences between the two groups. It was observed that this increase reached the preoperative values after 1-3 months and 6 months in both groups. There was no statistically significant change in the RNFL. Rectus muscle surgery (recession±resection) caused an increase in CMT and SFCT in the early stage, which was possibly caused by the altered choroidal microcirculation resulting from mechanical traction during surgery and by postoperative inflammation. There was no difference between one or two muscle surgeries.

Does exotropia surgery have a long-term effect on choroidal vasculature?

OBJECTIVE

To investigate the long-term effect of exotropia surgery on the choroidal structure.

MATERIAL AND METHOD

The study included 18 patients treated with medial rectus resection and lateral rectus recession for exotropia and 18 healthy patients as a control group. Demographic and clinical characteristics as well as enhanced depth imaging optical coherence tomography (EDI-OCT) scans were collected retrospectively. Images were binarized using ImageJ software; total choroidal area along with luminal and stromal areas (TCA, LA, and SA) were segmented, and CVI was computed as the ratio of LA/TCA. In addition, choroidal thickness (CT) was evaluated.

RESULTS

No significant differences were found between operated eyes, fellow eyes, and control group eyes in terms of CT, TCA, LA, SA, and CVI.

CONCLUSION

Strabismus surgery does not appear to negatively effect the choroidal layer in the long term. We recommend that this surgery be performed without delay as it positively affects the psychological health of the patient and improves quality of life.

Evaluation of Visual Field and Balance Function Alterations in Patients Who Underwent Dermatochalasis Surgery

Purpose

To compare perioperative visual field (VF), balance functions (BF), and changes in the other ocular parameters in patients undergoing upper eyelid dermatochalasis (DC) surgery.

Methods

One hundred and fifty-eight eyes of 79 patients who underwent DC surgery were included in the study. The VF, BF, intraocular pressure (IOP), pachymetry (PM), macular, and optic nerve measurements were recorded. Measurements were repeated at postoperative month 1. The preoperative and postoperative ocular measurements and the balance data were compared.

Results

Nineteen of 79 (24.05%) patients were male and 60 of 79 (75.95%) were female, while the mean age of the patients was 58.65 ± 7.38 years. There were statistically significant differences in terms of VF and macular thickness between the preoperative and postoperative values. The improvements in mean defect, standard loss variance, and mean sensitivity values of global VF parameters in both eyes were statistically significant after surgery. Central macular thickness, mean macular thickness, and macular volume decreased significantly in all eyes after surgery (p < 0.05).

Conclusions

Although a marked improvement was observed in VF and peripheral vision after surgery, no significant change was found in BF parameters including primarily falling risk. The significant change in the macular parameters was only remarkable, and we think that the decrease was due to subtle vasospasm. There is a need for further comprehensive studies including especially patients older than 65 with a view to understanding the effect of DC surgery on BF.