Focal loss of laminar beams could cause lamina cribosa deformation

Lamina cribosa (LC) deformation in glaucoma can be caused by focal loss of laminar beams, claims a study in the Archives of Ophthalmology.

Dr Saman Kiumehr et al., Einhorn Clinical Research Center, New York Eye and Ear Infirmary, New York, USA, included 92 eyes of 31 patients. Of the patients studied, 46 were healthy control subjects and 45 were glaucomatous.

Optical coherence tomography images of the optic nerve head were obtained from both groups of patients. Focal LC defects were defined as anterior laminar surface irregularities, sptial consistency, neuroretinal rim thinning/notching and visual field defects.

There were 98 focal LC defects found in 34 glaucomatous eyes and seven of the 11 glaucomatous eyes had a deeply excavated optic disc. Focal LC defects mostly occurred in the inferior or inferotemporal far periphery of the LC.

It was found that focal LC defects limited to the inferior half of the optic disc typically have greater sensitivity loss in the superior visual hemfield. Focal LC defects tend to occur in correlation with neuroretinal rim and visual field loss.