Optic disc progression and rates of visual field change in treated glaucoma.

PURPOSE: To investigate the relationship between optic disc progression and rates of visual field (VF) change in patients with treated glaucoma. METHODS: Glaucoma patients with repeatable VF loss, ≥8 SITA-Standard 24-2 VF tests and good quality optic disc stereophotographs evaluated over a 10-year period were included. Optic disc photographs were reviewed for signs of glaucoma progression (neuroretinal rim change, widening of retinal nerve fibre layer defect, disc haemorrhage and enlargement of beta-zone parapapillary atrophy) by two glaucoma specialists masked to their temporal sequence. Disagreements were adjudicated by a third grader. VF progression was evaluated using automated pointwise linear regression (PLR) and defined as at least two adjacent test points progressing >1.0 dB/year at p < 0.01. VF progression outcomes were compared with photograph review results. RESULTS: Three-hundred and eighty nine eyes (389 patients; mean age 64.9 ± 13.0 years; mean baseline MD, -7.1 ± 5.1 dB) were included. Most patients had primary open angle glaucoma (54%). Eighty-two eyes (21%) had confirmed optic disc progression and 115 eyes (29%) met the VF PLR criteria. Eyes with documented optic disc progression had more rapid rates of VF change (-0.66 ± 0.7 versus -0.36 ± 0.7 dB/year, p < 0.01) and met the VF PLR endpoint more often (univariate OR = 1.85, p = 0.02; multivariate OR = 1.78, p = 0.03) than eyes without optic disc progression. There was moderate spatial consistency between the location of the optic disc progression and the hemifield with more rapid progression (81%, kappa = 0.40). CONCLUSIONS: Treated glaucomatous eyes with documented optic disc progression are at increased risk of diminished visual function over time and may require more aggressive therapy to prevent future vision loss. Among the indicators of structural progression, disc haemorrhage was the single most significant predictor for VF deterioration.

High resolution in vivo imaging of the lamina cribrosa.

The lamina cribrosa (LC) is considered to be the principal site of retinal ganglion cell axon injury in glaucoma. Imaging technology has steadily improved in recent years, allowing greater resolution of fine details of laminar structure. Histological studies have elucidated the details of LC structure, both in normal and glaucomatous eyes, but such studies are limited by smaller sample size, greater difficulty of conducting prospective studies, and possibility of altered tissue architecture during histologic processing. We reviewed the literature describing the LC in primate and human eyes using in vivo imaging devices and provided a brief explanation of the imaging technology and main results of the articles. We also discuss the advantages and limitations of each imaging modality described, including optic disk photography, confocal scanning laser ophthalmoscopy (CSLO) and optical coherence tomography (OCT). These modalities provide en face and/or cross-sectional images of the LC in vivo. Enhanced depth imaging OCT has recently led to important advances in imaging deeper structures of the posterior segment, including the LC. Adaptive optics has been adopted in CSLO and OCT imaging to correct for ocular aberration and has improved resolution and contrast of the LC images. Post-image processing techniques to compensate for light attenuation and enhance contrast in OCT images enabled better visualization of the LC beneath the neuroretinal rim, vascular structures, and scleral rim. Long-wavelength probe OCT has shown good visualization of the LC with improved penetration when combined with swept-source OCT. Contrast agents for enhanced visualization of selective target structures in OCT have been developed. All these technologies hold great promise for improved in vivo imaging of the LC and require further investigation.