Laterality Targeting in Graded Inferior Rectus Tenotomy Corrects Lateral Incomitance of Hypertropia in Sagging Eye Syndrome.

Purpose: To determine if laterally selective graded vertical rectus tenotomy (GVRT) of the inferior rectus (IR) can correct the lateral incomitance of hypertropia (HT) commonly encountered in sagging eye syndrome (SES), comparing it with inferior oblique (IO) recession.

Design: Retrospective comparative interventional clinical study.

Methods: We reviewed 73 consecutive patients undergoing GVRT of the IR for correction of horizontally incomitant HT due to SES from July 2012 to October 2023. Confounding diagnoses were excluded. Using topical anesthesia, GVRT was initiated from the nasal versus temporal side corresponding to greater HT, with dosing adjusted intraoperatively until cover testing in central gaze indicated orthotropia. We compared 8 cases of IO recession to 4 mm posterior and 3 mm lateral to the IR insertion.

Results: Nasal GVRT was performed in 41 patients, and temporal GVRT on 32 patients. Mean nasal GVRT was 69 ± 15% (standard deviation) and mean temporal GVRT was 62 ± 17%. Mean HT in central gaze was reduced by nasal GVRT from 3.9 ± 1.7Δ to 0.3 ± 1.4Δ, and from 4.0 ± 1.6Δ to 0.2 ± 1.1Δ by temporal GVRT. Nasal GVRT corresponding to the side of the tenotomy had greater effect in contralateral gaze at 3.2 ± 2.2Δ than ipsilateral gaze at 2.1 ± 2.0Δ (P = .025), whereas temporal GVRT had greater effect in ipsilateral gaze at 4.9 ± 2.7D than contralateral gaze at 2.9 ± 2.9D (P = .0002). Inferior oblique recession in 8 patients reduced lateral incomitance from 13 ± 5.0Δ to 0.5 ± 1.4Δ (P < .0001).

Conclusion: Nasal GVRT corrects about 1Δ and temporal GVRT 2Δ horizontal incomitance of HT, while IO recession corrects about 12.5Δ. Selection of GVRT laterality improves outcomes without additional risk or operating time.