| Identification of a Horizontal Invasion Length Threshold Predicting Posterior Corneal Flattening after Pterygium Excision |
|
Junga Oh1, Seung Hyeun Lee2, Kyoung Woo Kim1 |
1Department of Ophthalmology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
2Department of Ophthalmology, Chung-Ang University Gwangmyeong Hospital, Chung-Ang University College of Medicine, Gwangmyeong, Korea |
Correspondence:
Kyoung Woo Kim, Tel: 82-2-6299-1689, Fax: 82-2-825-1666,
Email: kkanssa@cau.ac.kr
|
|
Received: 11 December 2025 • Revised: 8 January 2026 • Accepted: 25 January 2026 |
| Abstract |
Purpose
To characterize perioperative changes in posterior corneal curvature (PCC) following pterygium excision using anterior segment swept-source optical coherence tomography (AS SS-OCT), and to identify the critical threshold of horizontal invasion length (HIL) predicting significant PCC alterations.
Methods
This retrospective cohort study included 85 eyes of 77 patients with primary nasal pterygium. PCC parameters, including posterior K average, posterior steep K, posterior flat K and posterior corneal astigmatism, were measured preoperatively and postoperatively using AS SS-OCT (Anterion®, Heidelberg Engineering, Heidelberg, Germany). Perioperative PCC changes were analyzed in relation to HIL and postoperative duration. Subgroup analyses were performed to identify the HIL cutoff value associated with statistically significant changes in posterior K average.
Results
Significant postoperative flattening was observed in both posterior K average (from -6.27 ± 0.24 D to -6.23 ± 0.23 D, P < 0.001) and posterior flat K (from -6.14 ± 0.23 D to -6.09 ± 0.23 D, P < 0.001), accompanied by a significant increase in posterior corneal astigmatism (from -0.25 ± 0.12 D to -0.29 ± 0.17 D, P = 0.003). The magnitude of posterior flattening showed a significant positive correlation with HIL (r = 0.384, P < 0.001) but was not correlated with postoperative duration (P = 0.428). In subgroup analysis, eyes with HIL ≥ 3.5 mm exhibited a significant change in posterior K average (P < 0.001), whereas those with HIL < 3.0 mm and HIL < 3.5 mm showed no significant change (P = 0.065 and P = 0.443, respectively).
Conclusion
Pterygium excision leads to significant posterior corneal flattening proportional to HIL, with 3.5 mm identified as a clinically relevant cutoff. Although the refractive impact may be subtle, surgeons should be aware of these posterior corneal changes as a consistent morphological response, especially in eyes with HIL ≥ 3.5 mm. |
| Key Words:
Anterion; Anterior swept-source OCT; Horizontal Invasion Length; Posterior Corneal Curvature; Pterygium |
|
PDF Links
Full text via DOI
Download Citation
