Simultaneous evaluation of the lamina cribosa position and choroidal thickness changes following deep sclerectomy

Non-arteritic anterior ischemic and glaucomatous optic neuropathy: Implications for neuroretinal rim remodeling with disease severity

PURPOSE

Post-acute non-arteritic ischemic optic neuropathy (NAION) and glaucomatous optic neuropathy (GON) can be difficult to differentiate clinically. Our objective was to identify optical coherence tomography (OCT) parameters to help differentiate these optic neuropathies.

METHODS

We compared 12 eyes of 8 patients with NAION and 12 eyes of 12 patients with GON, matched for age and visual field mean deviation (MD). All patients underwent clinical assessment, automated perimetry (Humphrey Field Analyzer II; Carl Zeiss Meditec, Dublin, CA, USA), and OCT imaging (Spectralis OCT2; Heidelberg Engineering, Heidelberg, Germany) of the optic nerve head and macula. We derived the neuroretinal minimum rim width (MRW), peripapillary retinal nerve fibre layer (RNFL) thickness, central anterior lamina cribrosa depth, and macular retinal thickness.

RESULTS

MRW was markedly thicker, both globally and in all sectors, in the NAION group compared to the GON group. There was no significant group difference in RFNL thickness, globally or in any sector, with the exception of the temporal sector that was thinner in the NAION group. The group difference in MRW increased with increasing visual field loss. Other differences observed included lamina cribrosa depth significantly greater in the GON group and significantly thinner central macular retinal layers in the NAION group. The ganglion cell layer was not significantly different between the groups.

CONCLUSIONS

The neuroretinal rim is altered in a dissimilar manner in NAION and GON and MRW is a clinically useful index for differentiating these two neuropathies. The fact that the difference in MRW between the two groups increased with disease severity suggests distinct remodelling patterns in response to differing insults with NAION and GON.

Early evaluation of optic nerve head morphology and choroidal thickness after PreserFlo MicroShunt implantation

PURPOSE

The aim of this study is to investigate changes in choroidal and optic nerve morphological parameters following MicroShunt PreserFlo implantation. The secondary aim is to investigate how the structural changes relate to the decrease in intraocular pressure (IOP).

METHODS

Prospective observational study on 15 eyes with glaucoma requiring MicroShunt implantation. Optical coherence tomography was used to measure macular choroidal thickness (MCT), peripapillary choroidal thickness (PCT), lamina cribrosa depth (LCD), cup depth and prelaminar tissue thickness (PLT), before and one day after surgery. Results were expressed in median and interquartile range (IQR) and correlated with IOP results.

RESULTS

The IOP decreased from a median of 25 (IQR = 11) mmHg to 8 (IQR = 2) mmHg the day after surgery. Median MCT increased after MicroShunt implantation from 252.1 (IQR = 156.4) µm to a postoperative value of 318.1 (IQR = 166.6) µm (p < 0.001), with a median increase of + 87.7 µm (+ 26.4%). PCT increased from 157.2 (IQR = 109.1) µm before surgery to 206.0 (IQR = 136.1) µm after surgery (p < 0.001). Moreover, we found a significant post-operative decrease in cup depth (median reduction of - 29.3 µm, p < 0.001) and an increase in PLT (median increase of 27.3 µm, p = 0.028). On the other side, LCD reduction 24 h after surgery didn't reach any statistical significance.

CONCLUSION

PreserFlo implantation determines retinal structural changes which appear similar to those caused by traditional filtering surgery, confirming the effectiveness of this device, meantime carrying a much smaller complications rate when compared to trabeculectomy.

EDI-OCT choroidal thickness in Posner-Schlossman syndrome

PURPOSE

To compare the choroidal thickness (CT) of the affected eyes with the contralateral eyes in the active period and in the remission period in Posner-Schlossman syndrome (PSS) using EDI-OCT.

PATIENTS AND METHODS

This prospective longitudinal study included 15 patients with PSS and 15 age- and sex-matched healthy subjects. All subjects underwent complete ophthalmologic examinations, and EDI-OCT was conducted to measure macular CT (mCT) at the subfoveal locations and at 0.5, 1.0 and 2.0 mm superior, inferior, nasal and temporal to the fovea. The mean measurements at each location were used for analysis. Linear regression analysis was performed to analyse the correlation between the choroidal thickness and IOP, and the correlation between the choroidal thickness and episode time.

RESULTS

The mean mCT was significantly thinner in affected eyes than in contralateral eyes in the acute phase (p = 0.010) but were not different in the remission phase (p = 0.404). The mean mCT was significantly increased in the remission phase compared to that in the acute phase in the affected eyes (p = 0.000). The mCT of healthy subjects was significantly thicker than in the affected eyes (p = 0.020) and similar to the fellow eyes of PSS patients (p = 0.357) in the acute phase. Linear regression analyses show negative correlations between the mCT changes and IOP changes in the affected eyes compared to those in the fellow eyes in the acute period (R² = 0.396, p = 0.033) and between the mCT changes and IOP changes from the acute period to the remission period in the affected eyes (R² = 0.372, p = 0.027). Linear regression analyses show positive correlations (age- and sex-matched) between the CT changes and episode time from the affected eyes to the fellow eyes in the acute period (R² = 0.492, p = 0.012).

CONCLUSIONS

The mCT values of the PSS-affected eyes were significantly thinner than those of the fellow eyes in the acute phase and in the remission phase, and this change was correlated with IOP reduction and episode time.

Intereye Comparison of Lamina Cribrosa Curvature in Normal Tension Glaucoma Patients With Unilateral Damage

Purpose

To investigate intereye differences in lamina cribrosa (LC) morphology in normal tension glaucoma (NTG) patients with unilateral damage.

Methods

A total of 152 eyes of 76 treatment-naive NTG patients with unilateral damage from the ongoing Investigating Glaucoma Progression Study were included. Optic nerve heads were scanned using enhanced-depth spectral-domain optical coherence tomography. The magnitude of the LC curve and LC position were assessed by measuring the LC curve index (LCCI) and LC depth (LCD), respectively, at seven locations spaced equidistantly across the vertical optic disc diameter. LCCI and LCD were compared between glaucomatous and fellow healthy eyes.

Results

Eyes with NTG had larger average LCCI and LCD than contralateral healthy eyes (for both P < 0.002). The LCCI was greater in the glaucomatous eyes at all seven locations (P < 0.001). Univariate conditional logistic regression analysis showed that higher baseline intraocular pressure (P = 0.010), deeper LCD (P = 0.007), and larger LCCI (P < 0.001) were significantly associated with the presence of glaucoma. In multivariate analysis, only larger LCCI was significantly associated with the presence of glaucoma (P < 0.001).

Conclusions

Glaucomatous eyes have more steeply curved LC than fellow healthy eyes. This finding suggests that LC undergoes significant remodeling in NTG eyes.