Changes in ocular surface after withdrawal of anti-glaucoma medications following non-penetrating deep sclerectomy.

Purpose: : To analyze the ocular surface changes in eyes after the withdrawal of anti-glaucomatous drugs when non-penetrating deep sclerectomy (NPDS) is performed. Methods: Thirty-one patients (33 eyes) diagnosed with glaucoma that underwent NPDS were included in this prospective study. The control group included 33 eyes. Four variables were studied using Keratograph 5M (K5M): ocular hyperemia (OH), non-invasive tear film break-up time (NI-BUT), lower tear meniscus height (LTMH), and meibography. LTMH was also measured using the anterior segment module of a Spectralis Fourier-domain optical coherence tomography (FD-OCT) instrument. Moreover, an evaluation of corneal and conjunctival staining was performed. In the glaucoma group, five visits were carried out: pre-surgery, 1 week after surgery, and 1 month, 3 months, and 6 months after surgery. In control groups, examinations were performed in only one visit. In addition, patients were asked to answer two questionnaires: Ocular Surface Disease Index (OSDI) and National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) before and 6 months after surgery. Results: Before NPDS, eyes showed worse objective data than healthy control subjects (P ≤ 0.049). In this group, a significant improvement was observed in questionnaire responses (P < 0.001), LTMH-FD-OCT (P = 0.037), LTMH-K5M (P = 0.025), K5M-OH (P = 0.003), NI-BUT (P = 0.022), and conjunctival and corneal staining (P < 0.001). No significant differences were observed between groups in FD-OCT and K5M LTMH, NI-BUT, corneal-conjunctival staining, nor in the most OH sector values at 6 months (P ≥ 0.62). Conclusion: A significant improvement in the ocular surface was observed 6 months after NPDS, suggesting that the withdrawal of the topical anti-glaucomatous treatment had a beneficial effect on the subjects.

Bruch's membrane opening changes and lamina cribrosa displacement in non-arteritic anterior ischaemic optic neuropathy.

PURPOSE: To describe the morphological changes in the lamina cribrosa (LC) and prelaminar tissue (PT) from eyes with non-arteritic anterior ischaemic optic neuropathy (NAION) using enhanced depth imaging (EDI) optical coherence tomography (OCT), and to evaluate whether these changes correlate with retinal nerve fibre layer (RNFL) thickness and visual acuity (VA). DESIGN/METHODS: A prospective case-control study was performed, including 17 study eyes with NAION and 17 control, uninvolved eyes from 17 patients. Eyes underwent scanning with Spectralis-OCT at onset, 2 and 6 months after NAION. Bruch's membrane opening (BMO), anterior LC surface depth (LCD), LC thickness and PT thickness (PTT) were compared between study and control eyes. Correlation analysis was performed to evaluate the association between these parameters, RNFL thickness and VA. RESULTS: At presentation, average PT was 58.6% thicker in NAION eyes compared with healthy control eyes (p=0.001), followed by a significant thinning at 2 and 6 months (p=0.001). A significant LC forward displacement was observed at 2 and 6 months (p=0.001). BMO progressively shrunk at 2 and at 6 months (p<0.05). A significant correlation was found between PTT and RNFL thickness (ρSpearman=0.544, p=0.024) at onset, as well as between PTT and RNFL changes at 6 months (ρSpearman=0.545, p=0.036). BMO and RNFL changes were also correlated at 6 months (ρSpearman=0.750, p=0.001). CONCLUSIONS: At onset, a significant PT thickening, backward LC movement and BMO enlargement occurred in NAION eyes compared with unaffected eyes, and these changes significantly reversed during follow-up. PTT and RNFL changes were significantly correlated.

Ganglion cell analysis at acute episode of nonarteritic anterior ischemic optic neuropathy to predict irreversible damage. A prospective study.

PURPOSE: To assess the capability of ganglion cell-inner plexiform layer (GCIPL) thickness analysis by optical coherence tomography (OCT) to detect early neuronal loss in nonarteritic anterior ischemic optic neuropathy (NAION). METHODS: Sixteen patients with unilateral NAION participated in this prospective study. Complete ophthalmologic evaluation including visual acuity, visual field (VF) test, and spectral domain optical coherence tomography (SD-OCT) of peripapillary retinal nerve fiber layer (pRNFL) and GCIPL thickness were performed in the acute phase (within 1 week: 2.7 ± 2.1 days) and at 2 weeks, 1 month, 3 and 6 months after diagnosis. The mean time elapsed from acute episode to irreversible damage detection by GCIPL and pRNFL analysis was registered. Correlations between the GCIPL thinning and functional parameters such as best-corrected visual acuity (BCVA) and visual field indices [mean deviation (MD) and visual field index (VFI)] in acute and chronic phase were also analyzed. RESULTS: NAION eyes showed a significant thinning of the mean GCIPLminimum (min) compared to the unaffected eyes as early as 2.2 days after symptoms onset (p = 0.017) and at each follow-up visit. (p ≤ 0.003). The mean GCIPL average (av) was also thinner in NAION eyes compared to uninvolved eyes at 1 (p = 0.003), 3 (p = 0.002) and 6 months (p < 0.001). At the acute phase, 100 % of NAION eyes showed significant pRNFL thickening, while abnormal thinning was evident in GCIPLav, GCIPLmin, and GCIPL deviation map analysis in 31.3, 56.3, and 62.5 % of NAION eyes. The abnormal thinning rates increased to 43.8, 75, and 81.3 % at 2 weeks and to 62.5, 100, and 100 % at 1 month, respectively. At 2 weeks, GCIPLmin thickness significantly correlated with both acute and chronic BCVA, MD, and VFI. Furthermore, the mean superior and inferior GCIPL thicknesses at 2 weeks associated with corresponding mean inferior and superior hemifield MD at 6 months. CONCLUSIONS: GCIPL analysis by SD-OCT can be considered as a useful biomarker to establish ganglion cell damage. GCIPL min and GCIPL deviation map are abnormally thinner in 56.3 % and 62.5 % of eyes at presentation, respectively. Therefore, both parameters are abnormally thinned in more than 50 % of eyes at presentation. At 2 weeks, GCIPL min thickness significantly correlated with chronic BCVA, MD and VFI; therefore, GCIPL min thickness can predict final visual dysfunction.

OCT: New perspectives in neuro-ophthalmology.

Optical coherence tomography (OCT) has become essential to evaluate axonal/neuronal integrity, to assess disease progression in the afferent visual pathway and to predict visual recovery after surgery in compressive optic neuropathies. Besides that OCT testing is considered a powerful biomarker of neurodegeneration and a promising outcome measure for neuroprotective trials in multiple sclerosis (MS). Currently, spectral-domain OCT (SD-OCT) technology allows quantification of retinal individual layers. The Ganglion Cell layer (GCL) investigation has become one of the most useful tools from a neuro-ophthalmic perspective. It has a high correlation with perimetry, is predictive of future progression and is a highly sensitive, specific of several neuro-ophthalmic pathologies. Moreover the superior correlation with clinical measures compared to peripapillary retinal nerve fiber layer (pRNFL) suggests that GCL analysis might be a better approach to examine MS neurodegeneration. In disorders with optic disk edema, such as ischemic optic neuropathy, papillitis and papilledema, reduction in RNFL thickness caused by axonal atrophy is difficult to distinguish from a swelling resolution. In this setting, and in buried optic nerve head drusen (ONHD), GCL analysis may provide more accurate information than RNFL analysis and it might be an early structural indicator of irreversible neuronal loss. Enhanced depth imaging OCT (EDI-OCT) provides in vivo detail of ONHD, allowing to evaluate and quantify the drusen dimensions. OCT is improving our knowledge in hereditary optic neuropathies. Furthermore, there is growing evidence about the role of OCT as an adjunctive biomarker of disorders such as Alzheimer and Parkinson's disease.

Ganglion cell layer analysis unmasks axonal loss in anterior optic neuritis.

Optical coherence tomography is a valuable tool for evaluating patients with neuro-ophthalmic disorders. In the acute phase of anterior optic neuritis (ON), peripapillary retinal nerve fiber layer (pRNFL) measurements can underestimate the amount of damage as axonal swelling could mask the true degree of RNFL loss. Contrary to pRNFL evaluation, we hypothesize that macular ganglion cell layer analysis could detect true neuronal loss before swelling resolution in anterior ON. We describe 4 patients with anterior ON in whom ganglion cell layer and inner plexiform layer (GCIPL) thinning was detected earlier than pRNFL loss. GCIPL analysis may provide more accurate information than pRNFL thickness and serve as an early structural indicator of irreversible neuronal loss.