Clinical and pathological correlation of cotton wool spots in secondary angle closure glaucoma.

Purpose: Cotton Wool Spots (CWS) are a commonly described retinal finding in the posterior segment associated with an extensive number of systemic diseases. The appearance of a CWS in the setting of glaucoma has rarely been reported and has not been correlated with pathology to localized loss of the nerve fiber layer previously. In this case report, we augment a previous report of an 18 year old female with a diagnosis of low grade ciliary body melanoma. This patient experienced eventual mechanical angle closure with a CWS appearing in the posterior pole in the setting of acute elevation of intraocular pressure (IOP). This eye underwent enucleation and pathology evaluation.

Observations: Fundus photography documented a CWS in the posterior segment during a period of acute elevation in IOP. Subsequently the eye was enucleated due to pain from refractory angle closure glaucoma secondary to low grade iris-ciliary body ring melanoma. The specific site of the prior CWS was studied with 1μ Epon retinal step sections stained with a novel AgNO3 solution. Light microscopy demonstrated a retinal nerve fiber layer scar and inner nuclear layer collapse in the prior location of the CWS. Light microscopy and transmission electron microscopy shortly after enucleation had demonstrated temporal quadrant laminar optic nerve (ON) retrograde axonal transport block.

Conclusions and Importance: Although not commonly associated with glaucoma, CWS can present in the setting of acute elevations of IOP and may be associated with loss of nerve fiber layer. This loss of nerve fiber layer can confound the ability to judge glaucoma progression based on nerve fiber layer thickness via optical coherence tomography and changes in disc contours. Patient care may benefit from care provider's awareness of this possible phenomenon in the setting of angle closure.