The following is a summary of “Histochemical and ultrastructural evaluation of myopic corneal lenticules based on refractive error,” published in the June 2024 issue of Ophthalmology by Oruz et al.

Researchers conducted a retrospective study exploring cellular degeneration, apoptosis, and ultrastructural variations in refractive lenticules (RL) from small incision lenticule extraction (SMILE) relative to spherical equivalent (SE) refraction values.

They enrolled 84 eyes of 42 patients, categorized into 2 groups based on SE values, group 1 (SE < 4 diopters) and group 2 (SE > 4 diopters). Patients outside the SE ranges were excluded. Each patient contributed 1 RL for light microscopy and immunohistochemistry and another for transmission electron microscopy (TEM). The immunohistochemical analysis included evaluating Caspase-3 for apoptosis and alpha-smooth muscle actin (α-SMA) for cell degeneration.

The results showed that group 1 exhibited higher collagen fiber density, greater glycoaminoglycan and glycoprotein staining intensity than group 2. The TEM revealed intact cell and nuclear membranes, peripheral heterochromatin, and larger nuclei in group 1, while group 2 displayed heterochromatin condensation and fragmentation, increased intracellular vacuoles, and cytoplasmic loss. Immunohistochemical analysis indicated significantly elevated levels of α-SMA and caspase-3 in group 2 relative to group 1 (P<0.001 for both).

Investigators concluded that RLs with higher SE values post-SMILE surgery exhibited significantly increased rates of cell degeneration and apoptosis, suggesting a more pronounced tissue response warranting careful consideration for reuse.

Source: onlinelibrary.wiley.com/doi/10.1111/ceo.14412