Postoperative drift and dose-response of strabismus surgery in thyroid eye disease: predicting desired outcomes with intraoperative adjustable sutures.

OBJECTIVE: To report outcomes of strabismus surgery in thyroid eye disease using intraoperative bow-knot adjustable sutures under topical anaesthesia and calculate prediction models for surgical correction and postoperative drift depending on surgical dose-response. METHODS: We retrospectively reviewed patients operated on from 2016 to 2021. A satisfactory outcome was defined as no diplopia with maintenance of vertical (<5 PD) and horizontal (<10 PD) stable alignment at primary gaze. Subjective diplopia corrected with prisms within successful motor alignment was defined as a fair result. Otherwise, the result was considered to be poor. RESULTS: A total of 73 patients were included (60 females, 82%). Mean preoperative horizontal and vertical deviations were 26.9 PD (19.1 SD), and 11.8 PD (7.6 SD), respectively. Mean horizontal drift was -3.2 PD (5.2 SD), whereas mean vertical drift was -3.4 PD (3.3 SD). A linear regression established a dose-response of 2.37 PD/mm for each medial rectus recession (p < 0.0001; r2 = 0.777) and 3.75 PD/mm for unilateral inferior rectus recession (p < 0.0001; r2 = 0.922). Final success rate was satisfactory in 62 patients (85%), fair in 7 patients (10%), and poor in 4 patients (5%). CONCLUSIONS: Muscle recession with intraoperative adjustable sutures is effective for the treatment of thyroid eye disease strabismus. Predictable dose-responses could be achieved with a drift toward overcorrection. Undercorrection proportional to the planned surgical dose should be the immediate postoperative target of choice. Other variables such as orbital decompression and concurrent vertical and horizontal surgery do not correlate with dose-response and postoperative drift. However, further studies are necessary to validate our findings.

Keratometric, Pachymetric, and Surface Elevation Characterization of Corneas With Fuchs Endothelial Corneal Dystrophy Treated With DMEK.

PURPOSE: To characterize pachymetric, keratometric, and surface elevation parameters in pseudophakic eyes with Fuchs dystrophy that underwent Descemet membrane endothelial keratoplasty (DMEK) and to compare these characteristics with those in normal pseudophakic eyes. METHODS: Postoperative corneal tomography with a median follow-up of 20 months was evaluated using the Pentacam tomographer on 46 DMEK eyes. Results were compared with data from an age-matched cohort of 46 normal eyes. Parameters included curvature analysis, keratometry values, corneal thickness (CT), pachymetric progression index, Ambrósio relational thickness, posterior elevation, and D-index values. Bonferroni correction was used for multiple comparisons. RESULTS: CT at the apex (mean difference 41 µm; 95% confidence interval 28-54) and CT at the thinnest point (46 µm; 33-60) were statistically significantly lower in the DMEK group (P < 0.001), whereas pachymetric progression index average (0.47; 0.32-0.62), Ambrósio relational thickness maximum (172; 126-228), IHD (0.096; 0.005-0.014), and the global D-index (1.03; 0.51-1.56) were significantly higher in eyes with DMEK (P < 0.001). The mean CT along the vertical and horizontal meridians was significantly lower in the DMEK group within the central 5 mm. A quarter and one half of the DMEK eyes had a CT of less than 500 µm at the apex or at the thinnest point, respectively. CONCLUSIONS: Resolution of corneal edema after DMEK was associated with a thinner-than-normal central cornea, steeper pachymetric progression from the thinnest point to the periphery, and some high-end outliers for posterior elevation values. Caution should be exerted in planning corneal refractive surgery for residual refractive errors.