[Unilateral or asymmetric PEX syndrome? An electron microscopy study]

Area of Science:

• Ophthalmology
• Pathology
• Extracellular Matrix Biology

Background:

• Pseudoexfoliation (PEX) syndrome involves abnormal extracellular material accumulation in ocular tissues.
• Clinically, PEX syndrome can manifest unilaterally or bilaterally, but the generalized nature of the matrix process challenges unilateral presentation.
• This study investigates the histopathology of fellow eyes in clinically unilateral PEX syndrome.

Purpose of the Study:

• To perform a detailed histopathological analysis of apparently unaffected fellow eyes in cases of
• unilateral
• PEX syndrome.

Main Methods:

• Transmission electron microscopy and immunohistochemistry were used.
• Five pairs of donor eyes with unilateral PEX syndrome and six normal control eyes were analyzed.
• Antibodies against LTBP-1 and HNK-1, known PEX deposit markers, were employed for light and electron microscopic immunolabeling.

Main Results:

• All contralateral eyes exhibited ultrastructural changes in the iris, ciliary body, and trabecular meshwork.
• PEX fibrils, microfibrillar precursors, and extracellular matrix accumulation were observed in various ocular tissues.
• LTBP-1 and HNK-1 positive deposits were identified in iris vessels and the dilator muscle of contralateral and PEX eyes, but not in controls.

Conclusions:

• The findings support PEX syndrome as a generalized, fundamentally bilateral disease.
• Clinically asymmetric manifestations of PEX syndrome are common.
• These subclinical findings necessitate consideration in the clinical management of PEX patients.