Surgical Treatment of IXT: Comparison of Eight-Year Outcomes

Journal Highlights

Ophthalmology, January 2024

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The best surgical approach to intermittent exotropia (IXT) has not been determined. On behalf of the Pediatric Eye Disease Investigator Group, Donahue et al. compared long-term outcomes for two techniques: bilateral lateral rectus recessions (BLRc) and unilateral lateral rectus recession with medial rectus resection (R&R). In a previous randomized controlled trial (RCT), the same research team observed no difference in three-year outcomes for these treatments. However, IXT can recur beyond year 3, so longer investigations are needed. In their eight-year study, the authors found no significant difference in the incidence of suboptimal outcomes for BLRc and R&R when the usual aftercare was followed.

The long-term RCT included partic­ipants of the original trial who agreed to continue annual follow-up through eight years postoperatively, with treat­ment (if needed) provided at the discretion of the investigator. The main outcome measure was suboptimal surgical outcome within eight years of randomization, defined as reoperation or any of the following noted at any visit: exotropia ≥10Δ by simultaneous prism cover test (SPCT) at distance or near range, constant esotropia ≥6Δ by SPCT at distance or near range, or loss of near-range stereoacuity of ≥0.6 log arcsec from baseline. Secondary outcomes included complete or near-complete resolution by eight years (exodeviation <10Δ by SPCT and prism alternate cover text [PACT] at distance and near and ≥10Δ reduction from baseline PACT at distance and near) and no need for reoperation or nonsurgical treatment for IXT.

According to Kaplan-Meier analysis, the cumulative probability of a suboptimal outcome by the eight-year mark was 68% (55 events among 101 at risk) after BLRc and 53% (42 events among 96 at risk) after R&R (95% CI: –2% to 32%; p = .08). The proportion of patients with complete or near-complete resolution by year 8 was 14% (six of 42) in the BLRc group and 37% (16 of 43) in the R&R group (95% CI, –44% to –0.1%; p = .049). The cumulative probability of reoperation was 30% following BLRc and 11% following R&R (95% CI, 2% to 36%; p = .049).

Although the primary outcome did not differ significantly by type of surgery, the 95% CI did not exclude the possibility of a modest benefit for R&R (but did exclude it for BLRc). This finding, coupled with the secondary outcomes, suggests that when followed by usual care, unilateral R&R may produce better long-term results than BLRc. The authors acknowledged that the overall outcomes were disappointing and emphasized the need to explore other surgical and nonsurgical treatments for IXT.

The original article can be found here.