Refractive changes after strabismus surgery

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.].

Postoperative outcome and influencing factors of strabismus surgery in infants aged 1-6 years

PURPOSE

To evaluate the postoperative outcome of strabismus surgery performed in children aged 1-6 years by investigating the change of the preoperative angle of deviation (AOD), elevation in adduction, best-corrected visual acuity (BCVA) and refractive error.

METHODS

Retrospective chart review of 62 children who received strabismus surgery between January 2018 and December 2021 at the Department of Ophthalmology and Optometry of the Medical University of Vienna. Age, sex, type of strabismus, AOD, BCVA, refractive error and visual acuity were evaluated with respect to the postoperative outcome.

RESULTS

Mean follow-up was 13.55 ± 11.38 months with a mean age of 3.94 ± 1.97 years (range: 1.0-6.0) at time of surgery. 74.19% of patients (n = 46) had isolated or combined esotropia, 12.90% (n = 8) had isolated or combined exotropia and 12.90% (n = 8) had isolated strabismus sursoadductorius. Mean preoperative AOD of 15.69 ± 16.91°/15.02 ± 14.88° (near/distance) decreased to 4.00 ± 9.18°/4.83 ± 7.32° (near/distance) at final follow-up (p < 0.001). BCVA improved from 0.26 ± 0.26/0.25 ± 0.23 (left/right) to 0.21 ± 0.25/0.20 ± 0.23 (left/right) (p = 0.038). There was no significant change regarding refractive error (p = 0.109) or elevation in adduction (p = 0.212). Success rate which was defined as a residual AOD of less than 10° was 74.19% (n = 46). In 3.23% (n = 2) retreatment was necessary.

CONCLUSION

Strabismus surgery in infants was shown to have a satisfactory outcome with a low retreatment rate. Surgical success rate was not linked to age, sex, type of strabismus or the preoperative parameters AOD, refractive error and visual acuity in this study.

Refractive changes after strabismus surgery in patients with intermittent exotropia

OBJECTIVES

To evaluate the long-term refractive changes after horizontal muscle surgery in patients with intermittent exotropia and investigate the correlation between changes in the postoperative refractive error and clinical factors.

METHODS

We retrospectively reviewed the clinical data of patients aged < 15 years who underwent unilateral strabismus surgery (lateral rectus recession and medial rectus resection [RR, n = 47], lateral rectus recession and medial rectus plication [RP, n = 81], or lateral rectus recession [LRc, n = 68]). Preoperative and postoperative refractive errors up to four years after surgery were recorded. A mixed model was applied to compare the refractive error between the operated and fellow eyes and identify the factors associated with postoperative refractive changes.

RESULTS

The mean age at surgery was 7.5±2.4years, and girls accounted for 56.1% of the study population. There was no significant difference in the change in the spherical equivalent of refractive error between both eyes throughout the postoperative period. In contrast, the operated eyes consistently and significantly showed higher cylindrical power in with-the-rule astigmatism by 0.25D than in fellow eyes. Age, sex, and preoperative refractive error were not correlated with changes in postoperative astigmatism. Meanwhile, the type of surgery showed a significant interaction with the astigmatism changes. RP had less effect on the changes in astigmatism than RR and LRc (p = 0.001 and p = 0.022, respectively).

CONCLUSIONS

Horizontal muscle surgery has no long-term effect on the change in the spherical equivalent. However, mild with-the-rule astigmatism is induced and sustained after surgery, and the type of surgery affects the postoperative change of astigmatism.

Unilateral transient high myopization after pediatric strabismus surgery: Observation by anterior segment optical coherence tomography

PURPOSE

To describe an unusual case of unilateral transient high myopization after pediatric strabismus surgery.

OBSERVATIONS

A 6-year-old girl with intermittent exotropia had undergone strabismus surgery and experienced a transient decrease in best-corrected visual acuity (BCVA, from 20/20 to 20/33) with high myopization (from +0.25 D to -9.00 D). Slit-lamp microscopy showed anterior chamber inflammation and a narrow angle only in the affected eye. Anterior segment optical coherence tomography (AS-OCT) revealed ciliary body detachment, a narrow angle, a shallow anterior chamber, and an anteroposterior elongation of the crystalline lens in the affected eye. Her symptoms of blurry vision and high myopization improved 8 weeks postoperatively. AS-OCT revealed the resolution of the ciliary body detachment, an open angle, and a deep anterior chamber, with normalization of the anteroposterior length of the crystalline lens. Her BCVA recovered to 20/20 with spherical equivalence of 0 D.

CONCLUSIONS AND IMPORTANCE

We reported on an extremely rare case of unilateral transient high myopization following strabismus surgery, which was resolved without additional surgery. This myopization was probably caused due to ciliary body inflammation.

Changes in refractive status of amblyopic patients with partially refractive esotropia

PURPOSE

To investigate the changes in refractive status of amblyopic patients with partially refractive esotropia (PAET).

MATERIALS AND METHODS

Amblyopic patients with PAET were enrolled. Non-amblyopic patients with full refractive accommodative esotropia (RAET) were included in the study as a control group. Preoperative and postoperative best-corrected visual acuity (BCVA), spherical equivalent (SE), astigmatism, stereoacuity, and deviations at near and distance were evaluated and statistically compared within the study group. Mean BCVA, SE, astigmatism were compared between the two groups.

RESULTS

The patient and the control groups were composed of 58 eyes of 29 patients per group. There were statistically significant differences between pre- and postoperative mean astigmatism and SE between the patient and control groups. The mean astigmatism was higher in amblyopic eyes when compared with the eyes in the control group (P:0.009). During the follow-up period, changes in SE and astigmatism were not different between groups.

CONCLUSION

The mean SE and astigmatism were changed in both amblyopic patients with PAET and non-amblyopic patients with RAET during the follow-up period. This suggested that neither amblyopia nor strabismus surgery has an effect on refractive status in patients with PAET.

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.

Effect of strabismus surgery on ocular axial length, anterior chamber depth, and intraocular pressure

We evaluated changes in ocular axial length (AL), anterior chamber depth (ACD), and intraocular pressure (IOP) after strabismus surgery by comparing the operated and fellow eyes in patients undergoing unilateral strabismus surgery.This was a prospective study including patients who underwent unilateral strabismus surgery for exotropia alone or exotropia with unilateral superior oblique palsy. The AL and ACD using IOLMaster biometer and the IOP using non-contact tonometry were measured 1 day prior to surgery and 1 week, 1 month, and 3 months postoperatively.Fourteen female and 22 male patients (mean age: 8.2 years) were included in the study. In the operated eye, the mean AL increased significantly from 23.99 mm preoperatively to 24.08 mm 1 week postoperatively (P < .001), and although the mean ACD decreased in this time, the decrease was not statistically significant. The mean IOP of the operated eye increased from 17.08 mmHg preoperatively to 20.31 mmHg at 1 week postoperatively (P = .01), as did the IOP of the fellow eye (P = .03). However, the AL and IOP of the operated eyes decreased by 1 month postoperatively. There were no significant differences in the AL, ACD, and IOP between operated and fellow eyes by 3 months postoperatively.Strabismus surgery caused significant AL elongation in the operated eye and IOP elevation in both the operated and fellow eyes immediately after surgery. However, both ocular changes were transient. The AL, ACD, and IOP did not exhibit any significant differences between operated and fellow eyes 3 months postoperatively.

The Effect of Strabismus Muscle Surgery on Corneal Biomechanics

Purpose

Studying the early effect of different extraocular muscle (EOM) surgeries on corneal biomechanics.

Subjects and methods

This is a prospective, nonrandomized, interventional study, in which 42 eyes of 29 candidates for EOM surgery for strabismus correction at Cairo university hospitals, aged 14–37 years, were recruited. All participants had measuring of the visual acuity, refraction (spherical equivalent (SE)), assessment of the EOM motility and muscle balance, sensory evaluation, fundus examination, and assessing the ocular biomechanics using the Ocular response analyzer (ORA, Reichert, INC., Depew, NY) noting the corneal hysteresis (CH) and corneal resistance factor (CRF) preoperatively. Same patients were reassessed using ORA 4 weeks postoperatively following a different standard EOM surgery (recti weakening/strengthening and inferior oblique weakening either (graded recession) according to the surgical indication, and ∆CH and ∆CRF were calculated, each is the preoperative − the postoperative value.

Results

∆CH and ∆CRF = −0.78 ± 1.56 and −0.72 ± 2.15, respectively, and a highly significant difference was found between each of the pre- and postoperative CH and CRF (p < 0.001). 18 eyes had single EOM surgery, while 24 had multiple (2 or 3) EOM surgery; ∆CH in the single group = −1.28 ± 1.5, and ∆CH in the multiple group = 0.4 ± 1.49 (p=0.07). 23 eyes had EOM weakening surgery, while 18 had combined weakening and strengthening EOM surgery: ∆CH in the weakening group = −1.24 ± 1.77 and ∆CH in combined group = −0.26 ± 1.07 (p=0.04). A nonsignificant difference was found for ∆CRF (p=0.53).

Conclusion

A different EOM surgery has an early tendency for increase of the postoperative CH specially for muscle weakening procedures (recti recession/inferior oblique muscle weakening).