Findings from a recent study published in JAMA Ophthalmology compared the clinical outcomes of femtosecond laser arcuate keratotomy (FSAK) and toric intraocular lens (TIOL) implantation for astigmatism correction in patients undergoing femtosecond laser-assisted cataract surgery (FLACS).
Give me some background.
Due to decades of advancements and innovations in ophthalmology, cataract surgery has undergone a paradigm shift to refractive surgery in the modern era.
However: Residual astigmatism remains a key factor that influences patients’ visual quality and satisfaction.
Tell me more about FSAK.
In recent years, FSAK has emerged as a superior alternative to manual arcuate keratotomy as it offers improved precision and consistency.
- Even further: The procedure has proven to be an effective approach for astigmatism correction.
Previous studies have demonstrated that TIOL implantation and FSAK are also effective approaches for addressing astigmatism, with comparable results between the two.
- Note: These studies were limited by nonrandomized designs and relatively small sample sizes.
As such: A research team sought to compare the efficacy of these two approaches in treating residual astigmatism with a randomized clinical trial.
Now talk about the study.
In this study, investigators included 196 patients (mean age: 68.4 years; 63% female) who were randomly assigned in a 1:1 ratio to receive FSAK or TIOL implantation.
Important to note: Of the included patients, 92 (94%) and 95 (97%) finished the 3-month follow-up in the FSAK and TIOL groups, respectively.
Main outcome measure: The subjective manifest refraction assessed at 3 months postoperatively.
Findings?
At 3 months postoperatively, there was no difference in refractive astigmatism between the two groups (mean 0.64D vs. 0.54D, difference: 0.11D, 95% confidence interval [CI] -0.06-0.27D, P=0.21).
The mean uncorrected distance visual acuity (VA) was 20/28 for the FSAK group and 20/28 for the TIOL group (difference: 0.01D, 95% CI -0.04-0.06, P=0.71).
Subgroup analyses demonstrated that TIOL implantation achieved lower residual astigmatism compared with FSAK when treating astigmatism exceeding 1.5D or against-the-rule (ATR) astigmatism.
Expert opinion?
“Vector analysis of the refractive astigmatism showed that the TIOL group exhibited larger surgically induced astigmatism (SIA) and correction index than the FSAK group, suggesting greater effectiveness in astigmatism correction,” the study authors highlighted.
Limitations?
These included:
- Absence of masking among patients and surgeons may introduce a source of bias
- Follow-up period limited to 3 months, preventing an assessment of long-term stability and efficacy of both procedures
- As the primary outcome did not reveal a difference between the groups, secondary outcomes and subgroup analyses should be interpreted as exploratory and require validation
- All surgical procedures were performed by a single surgeon, limiting the generalizability of results
- VA was not measured using the Early Treatment Diabetic Retinopathy Study (ETDRS) approach
- Only one eye of the patient was included, which precluded analysis of patient satisfaction, spectacle independence, binocular VA, etc.
- The corneal biomechanical parameters could be further analyzed to enhance researchers’ understanding of the mechanisms underlying FSAK and improve the efficacy of current nomograms
Take home.
These findings suggest that FSAK was not superior to TIOL implantation for astigmatism correction in patients with mild to moderate astigmatism undergoing FLACS.
However: For astigmatism exceeding 1.5D or ATR astigmatism, TIOL implantation showed greater efficacy over FSAK.
Next steps?
Future trials with extended follow-up periods are required to determine if there is greater efficacy in TIOL implantation over FSAK, as suggested by the findings from the subgroup analyses.