Acute acquired concomitant esotropia (AACE) is gaining attention as it continues to impact vision, particularly among children and adults who have been increasingly reliant on screens. A prospective study conducted at the First Affiliated Hospital of Fujian Medical University has highlighted the efficacy of the prism and Maddox rod test (PMT) for determining surgical targets to address small-angle AACE. Published on March 16, 2025, this study reveals the test's potential as not just reliable, but also practical for guiding surgical interventions.
This retrospective study analyzed the cases of 33 patients diagnosed with small-angle AACE who underwent unilateral medial rectus recession (MRrec) surgery from June 2017 to May 2023. Each patient was subjected to thorough clinical testing, including the Hirschberg test (HT), PMT, and the prism and alternative cover test (PACT) to measure deviation angles at both near and distance viewing distances.
A noticeable trend observed was the alarming rise of AACE cases beginning from 2018, with cases spiking significantly during the COVID-19 pandemic. This rise can be attributed to the increased usage of electronic devices, which can lead to discomfort and visual issues.
Exploiting the advantages of PMT, the researchers found mean deviation angles at near and distance to measure 23.67 ± 5.44 prism diopters (PD) and 24.82 ± 5.49 PD, respectively, significantly higher than the measurements obtained from PACTmin, which were at 15.18 ± 5.12 PD and 15.24 ± 5.06 PD.
Post-surgery evaluations pointed to the success of using PMT for surgical guidance, with mean deviation angles for distance and near viewing reduced dramatically to 0.73 ± 1.69 PD and 0.61 ± 1.35 PD, respectively. All patients demonstrated remarkable surgical outcomes, achieving normal binocular vision and the disappearance of previously experienced double vision.
The approach utilized indicates the reliability of PMT, providing clear and consistent measurement outcomes. The authors noted, "PMT serves as a reliable and practical method for determining surgical targets in patients with small-angle AACE." This not only validates the testing procedure but also emphasizes the need to implement such standards consistently across other surgical practices addressing AACE.
One significant aspect emerged concerning muscle insertion. Fourteen out of the 33 patients experienced anterior displacement of the medial rectus muscle insertion during surgery, indicating relationships between muscle positioning and surgical outcomes. Such observations call for enhanced frameworks around preoperative evaluations to understand the physical anatomy of patients more thoroughly.
The study also revealed broader insights about AACE, without ignoring the impact of prior non-surgical interventions like prismatic corrections and botulinum toxin injections, which provide only temporary relief. The PMT's ability to disrupt fusional vergence allows for precise evaluations, making it more effective than previous methods, which often led to under-correction of surgical targets. This sustained change underlines the importance of utilizing updated methodologies like PMT for individualized and effective surgical planning.
While the research yielded positive changes and highlights the application of PMT, the authors cautioned against generalizing the results across all AACE patients without conducting larger-scale studies. They emphasized the requirement for multicenter research to confirm these findings and thoroughly explore the nuances presented during surgical assessments.
Ongoing studies will address this need to validate the PMT's broader applicability and refine the techniques used to manage AACE. The authors conclude, underscoring the necessity for consistent evidence-based practices to navigate the pathways leading to successful surgical interventions, encouraging continual advancements and improved outcomes for patients suffering from AACE.