Thank you for the opportunity to respond to the concerns raised by Dr. J.C.L. Schuh’s letter
1 and to clarify aspects of our manuscript. Dr. Schuh refers to the possibility that the observed lesions might represent a conjunctiva-associated lymphoid tissue (CALT) reaction rather than an inflammatory response linked to pterygium-like lesion induction. This is important to consider. CALT is assumed to play a key role in the protection of the ocular surface by initiating and regulating immune responses in the conjunctiva.
2 Questions remain regarding the cellular changes in CALT during ocular surface injury, particularly in the context of pterygium development in both human and animal models. Further work is necessary regarding the potential involvement of CALT in this process.
In our article, we discussed the challenges of establishing an animal model for pterygium, particularly due to the complexity of replicating ultraviolet irradiation–induced mechanisms. Although we were unable to reproduce elastosis and the typical triangular shape of the pterygium in our recent
3 and past study,
4 we were able to induce a chronic response after conjunctival injury. This emphasizes the limitations of existing models and highlights the originality of our approach. Specifically, we propose the rabbit as a viable model for inducing a pterygium-like lesion, which could also serve as a model for future studies on the potential role of CALT in ocular surface damage.
Concerning the natural history of CALT in rabbits, it is well documented that CALT is present from as early as 11 days postnatally, stabilizes in adolescence (2–4 months), and then declines in older rabbits.
5 In our study, rabbits were 3 months of age, a period when CALT is stable. Also, it is important to note that CALT presence is less common in the superior bulbar conjunctiva.
5 In our histological findings in normal conjunctiva (Fig. 3A), CALT changes were not observed in the superotemporal quadrant of each eye, the selected site for the injection of murine fibroblasts and Matrigel extracellular matrix.
The examination of the role of CALT in the pathophysiology of conjunctival lesions such as pterygium will be important future work. Our study provides a valuable platform for advancing this field of research, and we are optimistic that further exploration of CALT in our rabbit model will yield meaningful insights.
For the histopathological analysis, because only subconjunctival tissue samples from the site of injection were taken, the suggestion of sections of a whole-eye analysis with attached conjunctiva (en bloc) is not possible at this time.