Pre-, Intra-, and Post-Operative Evaluation of Extraocular Muscle Insertions Using Optical Coherence Tomography: A Comparison of Four Devices

OCT (optical coherence tomography) is widely used in ophthalmology and pediatric ophthalmology, but limited research has been done on the use of OCT in strabismus. This study investigates the use of different OCT machines to image rectus muscle insertions pre-, intra-, and post-operatively in pediatric strabismus patients. The OCT machines used in the study were a Bioptigen (Leica Microsystems Inc., Buffalo Grove, IL, USA), Spectralis HRA+OCT with Anterior Segment Module (Heidelberg Engineering, Heidelberg, Germany), Visante (Carl Zeiss, Oberkochen, Germany), and Zeiss Rescan 700 (Carl Zeiss, Oberkochen, Germany). Measurements from the machines were compared with the caliper distance measured during the strabismus surgery before disinsertion or after reattachment. The OCT machines had moderate (Bioptigen: 0.62) to good intraclass correlation coefficients (Rescan: 0.83, Spectralis: 0.85, Visante: 0.88) with intra-operative measurements. To our knowledge, this is the first study to use an operating microscope with integrated intra-operative OCT to image rectus muscle insertions. OCT is a useful tool in strabismus surgical patients in the pre-, intra-, and post-operative settings, particularly in patients who have had previous surgery, when the muscle insertion is unknown. The ability to accurately image rectus muscle insertions has significant implications for the management of strabismus patients

Rectus muscle plication using an adjustable suture technique

PURPOSE: Rectus muscle plication is an alternative muscle-strengthening procedure to rectus muscle resection. Possible advantages of rectus muscle plication include a lower risk of lost muscles and anterior segment ischemia. METHODS: This was a retrospective case series describing a surgical procedure for rectus muscle plication using an adjustable suture technique that can be used on any of the four rectus muscles. RESULTS: A total of 5 adult patients underwent adjustable suture plication procedures. Of these, 2 patients required suture adjustment postoperatively. At the final follow-up visit, all the patients maintained satisfactory ocular alignment within 6(Δ) of orthotropia for horizontal deviations and 2(Δ) of orthotropia for vertical deviations. Diplopia was eliminated in all cases with preoperative diplopia. There were no postoperative complications or unexpected shifts in ocular alignment. CONCLUSIONS: Rectus muscle plication using this adjustable suture technique may serve as an alternative to rectus muscle resection and may be particularly useful in patients who are at risk for anterior segment ischemia or those in whom a shorter anesthesia time is recommended

Hypertropia in unilateral isolated abducens palsy

PURPOSE: To evaluate the incidence and features of hypertropia in abducens nerve palsy. METHODS: The records of consecutive patients with unilateral, isolated, previously unoperated abducens nerve palsy were reviewed for binocular alignment on cover testing, Krimsky measurement, or Hess screen testing. Patients with associated cranial nerve palsy (including bilateral abducens palsies), orbital disease, myasthenia gravis, Horner syndrome, hemiplegia, cerebellar signs, arteritis, or previous strabismus surgery were excluded. Control subjects underwent complete examination to confirm normality. RESULTS: A total of 79 patients were included (40 males; mean age 49.2 years). Hypertropia in lateral or central gazes was present in 15 of 79 cases (19%) on alternate cover or Krimsky testing, in 32 of 56 cases (57%) on Hess screen testing, and absent in all 30 normal controls. Of cases with hypertropia, the mean of the greatest hypertropia in lateral or central gaze on was 5.0(Δ) ± 2.3(Δ) (standard deviation; range, 1(Δ)–8(Δ)) routine clinical examination, and 5.8(Δ) ± 4.2(Δ) (range, 2(Δ)–24(Δ)) on Hess screen testing. Of 39 cases with partial abducens palsy evaluated by Hess screen testing, the ipsilesional eye was hypertropic in 24 (61%) and hypotropic in 15 cases (39%). CONCLUSIONS: Small-angle hypertropia is common in isolated, unilateral abducens and does not necessarily imply existence of multiple cranial neuropathies or skew deviation