Changes in choroidal thickness, axial length, and ocular perfusion pressure accompanying successful glaucoma filtration surgery

Retinal Pigment Epithelial Tears after Ex-PRESS Filtration Surgery in a Glaucoma Patient with a History of Ischemic Optic Neuropathy

Background

To describe a case of retinal pigment epithelial tears (RPE tears) and serous retinal detachment (SRD) after Ex-PRESS filtration surgery for primary open-angle glaucoma (POAG) combined with ischemic optic neuropathy. Case Presentation. This case report involved a 69-year-old woman who underwent Ex-PRESS filtration surgery for right POAG. She had a history of systemic arteriosclerotic disease and subacute progressive visual field loss due to suspected ischemic optic neuropathy in her right eye. The right preoperative visual acuity was 0.7, and intraocular pressure (IOP) was 19 mmHg with maximum glaucoma eye drops. RPE detachment was not observed in the fundus. On day 9 after surgery, the IOP was 6 mmHg, and mild choroidal detachment was observed. On day 13, although IOP remained almost unchanged at 7 mmHg, bullous SRD was observed in the inferior retina, including the macula, and RPE tears were observed along the superior arcade vessel. While subretinal fluid gradually decreased with increasing IOP, tractional retinal folds persisted along the superior arcade, accompanied by macular degeneration.

Conclusion

We experienced a case of RPE tears after Ex-PRESS filtration surgery. In addition to choroidal detachment in the setting of hypotony, a pathologic condition causing structural fragility of the RPE layer may contribute to the development of RPE tears.

Early post-operative anterior segment parameters modifications induced by PreserFlo MicroShunt in primary open-angle glaucoma

PURPOSE

The aim this study is to determine anterior chamber parameters variations induced by PreserFlo MicroShunt implantation, in the early post-operative days.

METHODS

This is a prospective observational study on 48 eyes undergoing PreserFlo MicroShunt implantation alone (n = 30) or combined with phacoemulsification (n = 18). Anterior chamber depth (ACD) and volume (ACV), central corneal thickness (CCT) and total corneal astigmatism (TCA) were evaluated pre-operatively, post-operatively at day-1 and at 1 week with the Pentacam tomography.

RESULTS

Intraocular pressure decreased significantly from 20.9 ± 4.0 to 8.0 ± 2.8 mmHg (p < 0.0001) and to 10.8 ± 3.7 mmHg (p = 0.0001) at day-1 and week-1, respectively. TCA varied significantly from baseline (1.5 ± 1.2 D) to both day 1 follow up (2.7 ± 1.9 D, p = 0.0003) and week 1 follow up (2.2 ± 1.6 D, p = 0.02). Nevertheless, only K1 showed a transient flattening at day 1, while K2 value didn't show any statistical variation in the early post-operative period. CCT value rose significantly at day 1 (547 ± 49 vs. 529 ± 32 µm at baseline, p = 0.04), but then returned toward pre-operative values at week 1 (537 ± 39 µm, p = 0.57). In contrast, ACD values changed insignificantly from 3.3 ± 0.9 to 3.7 ± 1.0 mm at day 1 (p = 0.21), and then stabilized at 3.4 ± 0.9 mm (p = 0.82) at week 1 follow up. ACV changed from 150.0 ± 36.2 to 159.5 ± 42.1 mm³ at day 1 (p = 0.58), and successively to 153.9 ± 37.9 mm³ at week 1 follow up (p = 0.96). The subgroup analysis in eyes undergoing standalone PreserFlo implantation didn't show significant changes in both ACD and ACV.

CONCLUSION

PreserFlo implantation minimizes the anterior chamber modifications generated by traditional filtering surgery, inducing low and transient corneal and biometric changes only in the very early postoperative period and insignificant changes to ACD and ACV, label of its safety and minimal invasiveness.

Pressure-Dependent Elevation of Vasoactive Intestinal Peptide Level in Chicken Choroid

PURPOSE

Autonomic control is important in maintaining ocular integrity. As recent data suggested that intrinsic choroidal neurons (ICN), an intrinsic choroidal autonomic control, may regulate choroidal thickening via release of the vasodilative vasoactive intestinal peptide (VIP), it was the aim of the study to investigate the level of choroidal VIP (VIP_chor) in the presence of an increased atmospheric pressure in a chicken model.

METHODS

Chicken choroidal whole mounts were exposed to ambient pressure (n = 20) and 40 mm Hg (n = 20) in a PC-controlled, open chamber system for 24 and 72 h, respectively. The VIP concentration was analyzed by ELISA, and the total protein concentration was measured by the BCA assay. Statistical analysis was done using an unpaired two-tailed t-test.

RESULTS

The pressurization systems enabled choroidal whole mount pressurization (40 mm Hg) with humidifying, pressure, temperature, and gas exchange. Overall, the VIP_chor level concentration was significantly increased at 40 mmHg compared to the ambient pressure (30.09 ± 7.18 pg vs. 20.69 ± 3.24 pg; p < 0.0001). Subgroup analysis yielded a significantly increased VIP_chor level at 40 mmHg compared to the ambient pressure after 24 h (28.42 ± 6.03 pg vs. 20.76 ± 4.06 pg; p = 0.005) and 72 h (31.77 ± 7.82 pg vs. 20.61 ± 2.12 pg; p = 0.002), respectively. The VIP_chor elevation at 40 mm Hg ranged between 1.37- (24 h) and 1.54-fold (72 h) compared to the ambient pressure. No difference was observed between the VIP_chor level at 24 h and 72 h (p > 0.05).

CONCLUSIONS

The increase of the total choroidal VIP level, representing the intracellular VIP content, in the presence of an increased ambient pressure argues for a retention of VIP within the neurons, decreasing both vasodilatation and, consequently, choroid thickness. This finding might be a passive or even active function of ICN in the regulation of choroidal thickness, ocular integrity and IOP.

The Effect of the Water Drinking Test on Ocular Parameters and Choroidal Thickness in Glaucoma Suspects

Background and objectives: We aimed to evaluate the effects of the water drinking test (WDT) on several systemic and ocular parameters, including choroidal thickness, which was assessed through optical coherence tomography angiography (OCTA), in glaucoma suspects. Materials and Methods: A total of 40 eyes from 20 glaucoma suspects without any systemic or ocular diseases were included in this prospective observational study. All the participants undertook the WDT, which required the drinking of 1 L of table water in 5 min. The outcome measures included IOP, systolic and diastolic blood pressure (SBP and DBP), mean arterial pressure (MAP), mean ocular perfusion pressure (MOPP), ocular pulse amplitude (OPA), and subfoveal and peripapillary choroidal thickness, which were assessed at baseline and at four 15 min intervals after the WDT. Generalized least squares models and mixed model analyses that take into account repeated measurements were used to assess the changes over time of these parameters. Results: All the ocular and systemic parameters showed statistically significant changes at all time points compared to baseline apart from choroidal thickness. The peak changes were an IOP of 20.1 mmHg versus 17.3 mmHg at 45 min, an SBP of 137.6 mmHg versus 125 mmHg at 30 min, a DBP of 95.9 mmHg versus 85.7 mmHg at 15 min, and an MOP of 53.51 mmHg versus 48.89 mmHg at 15 min. Conclusions: Despite elevations in IOP and significant changes in all the assessed systemic parameters, the WDT was not associated with changes in choroidal thickness in glaucoma suspects.

Changes in intra-ocular pressure, ocular pulse amplitude and choroidal thickness after trabeculectomy

CLINICAL RELEVANCE

Glaucoma is one of the most common causes of blindness. Although high intra-ocular pressure (IOP) is the most important risk factor, ocular blood flow also has an effect on prognosis.

BACKGROUND

The aim of this study was to investigate the IOP, ocular pulse amplitude (OPA) and choroidal thickness (CT) changes after trabeculectomy and to determine whether trabeculectomy has an effect on ocular blood flow.

METHODS

This retrospective, comparative case series was conducted with 33 eyes of 33 patients who underwent trabeculectomy due to uncontrolled glaucoma. The fellow eyes of 20 patients who were followed up with medical therapy were included as a control group. IOP and OPA were evaluated using a dynamic contour tonometer. Subfoveal choroidal thickness (SFCT) was obtained with enhanced depth imaging (EDI) mode of Spectralis-OCT.

RESULTS

The mean IOP was 21.6 ± 6.3 mmHg at baseline and 13.8 ± 0.9 mmHg after trabeculectomy (p ˂ 0.001), and the mean OPA was 4.1 ± 1.5 at baseline and 2.6 ± 1.6 mmHg after trabeculectomy (p ˂ 0.001). The mean SFCT was 292.2 ± 63.2 µm at baseline and 303.8 ± 70.4 µm after trabeculectomy (p = 0.024). The change in OPA was strongly positively correlated with the change in IOP (r = 0.597, p ˂ 0.001) and SFCT change was positively correlated with OPA change (r = 0.34, p = 0.05). There was no difference between the two groups in terms of IOP, OPA and SFCT values measured after trabeculectomy (respectively, p = 0.264, p = 0.627 and p = 0.949).

CONCLUSION

The large IOP decrease following trabeculectomy causes a decrease in OPA and choroidal thickening. On the other hand, trabeculectomy has no effect on OPA change.

Predictive Modeling of Long-Term Glaucoma Progression Based on Initial Ophthalmic Data and Optic Nerve Head Characteristics

Purpose

The purpose of this study was to develop a model, based on initial optic nerve head (ONH) characteristics, predictive of long-term rapid retinal nerve fiber layer (RNFL) thinning in patients with open-angle glaucoma (OAG).

Methods

This study evaluated 712 eyes with OAG that had been followed up for >5 years with annual evaluation of RNFL thickness. Baseline ophthalmic features were incorporated into the machine learning models for prediction of faster RNFL thinning. The model was trained and tested using a random forest (RF) method, and was interpreted using Shapley additive explanations. Factors associated with faster rate of RNFL thinning were statistically evaluated using a decision tree.

Results

The RF model showed that greater lamina cribrosa (LC) curvature, higher intraocular pressure (IOP), visual field mean deviation converging towards −5 dB, and thinner peripapillary choroid at baseline were the four most significant features predicting faster RNFL thinning. Partial interaction between the features showed that larger LC curvature was a strong factor for faster RNFL thinning when it exceeded approximately 12.0. When the LC curvature was ≤12, higher initial IOP and thinner peripapillary choroid played a role in the rapid RNFL thinning. Based on the decision tree, higher IOP (>26.5 mm Hg), greater laminar curvature (>13.95), and thinner peripapillary choroid (≤117.5 µm) were the 3 most important determinants affecting the rate of RNFL thinning.

Conclusions

Baseline ophthalmic data and ONH characteristics of patients with OAG were predictive of eyes at risk of faster progression. Combinations of important characteristics, such as IOP, LC curvature, and choroidal thickness, could stratify eyes into groups with different rates of RNFL thinning.

Translational Relevance

This work lays the foundations for developing prediction models to estimate glaucoma prognosis based on initial ONH characteristics.

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.

Choroidal Thickness Increase after Subliminal Transscleral Cyclophotocoagulation

Background: The purpose of this study is to estimate the success rate of subliminal transscleral cyclophotocoagulation for refractory glaucoma and to determine the correlation between the decrease in intraocular pressure and the variation in choroidal thickness. Methods: A pre−post study was conducted over a period of 3 years, including 81 eyes from 67 patients with different types of drug-refractory glaucoma who underwent subliminal transscleral cyclophotocoagulation. The variables included best-corrected visual acuity, intraocular pressure and choroidal thickness. Results: We observed the following success rates (defined as IOP < 21 mmHg): 80% at 1 month (65 patients), 74% at 3 months (60 patients), 64% at 6 months (52 patients) and 50.6% at 1 year (41 patients). A strong correlation was noted between the decrease in intraocular pressure and the increase in the average choroidal thickness at 1 year (318.42 µm) compared to the average preoperative thickness (291.78 µm). A correlation of increased choroidal thickness at 1-month with the success rate of the procedure was also observed. Conclusions: We observed a statistically significant correlation between the success rate, decrease in intraocular pressure and choroidal thickness. The correlation of increased choroidal thickness at 1-month with the success rate of the procedure could be used clinically as a predictive factor for the final outcome of patients. Further experimental research is warranted to determine whether the increase in choroidal thickness after subliminal transscleral cyclophotocoagulation is indeed evidence of increased uveoscleral drainage.

Changes in optic nerve head and macula optical coherence tomography angiography parameters before and after trabeculectomy

Purpose

To evaluate the effects of lowering intraocular pressure (IOP) on foveal avascular zone (FAZ), peripapillary and macular vessel density (VD) by optical coherence tomography angiography (OCTA) in patients with open angle glaucoma after trabeculectomy.

Study design

Prospective study

Methods

Twenty eyes of 20 patients with primary open angle glaucoma (POAG) or exfoliation glaucoma (EG) who were followed up to six months and underwent trabeculectomy were included in our study. OCTA, AngioVue (Optovue Inc.) software was used to analyse the FAZ, peripapillary VD, macular superficial capillary plexus (SCP) and deep capillary plexus (DCP) VD. The parameters of the preoperative and postoperative controls were compared statistically.

Results

Twelve of the patients (60%) had POAG and eight (40%) had EG. Mean IOP measured was 22.4±2.4 mmHg preoperatively and 14.9±2.4 mmHg in the postoperative sixth month (p <0.001). There were no significant changes in OCTA optic disc and macular SCP VD values at the end of the sixth month. In macular DCP parameters; whole image VD (WI-VD), foveal VD (F-VD), parafoveal VD (PAF-VD) and perifoveal VD (PEF-VD) values increased statistically (p=0.003; p=0.026; p=0.006; p=0.004). There was a statistically significant decrease in FAZ area (FAZ-A) and FAZ perimeter (FAZ-P); and a significant increase was found in foveal density values (FD) (p=0.026; p=0.049; p=0.005).

Conclusions

We found that reducing IOP by trabeculectomy did not affect the microcirculation of the peripapillary region and macular SCP, while there was a significant increase in the DCP parameters of the macular region.

Effect of SCUBA Diving on Ophthalmic Parameters

Background and Objective: Several cases of central serous chorioretinopathy (CSC) in divers have been reported in our medical retina center over the past few years. This study was designed to evaluate possible changes induced by SCUBA diving in ophthalmic parameters and especially subfoveal choroidal thickness (SFCT), since the choroid seems to play a crucial role in physiopathology of CSC. Materials and Methods: Intraocular pressure (IOP), SFCT, pachymetry, flow-mediated dilation (FMD), blood pressure, and heart rate were measured in 15 healthy volunteer divers before diving, 30 and 60 min after a standard deep dive of 25 m depth for 25 min in a dedicated diving pool (NEMO 33). Results: SFCT reduces significantly to 96.63 ± 13.89% of pre-dive values (p = 0.016) 30 min after diving. It recovers after 60 min reaching control values. IOP decreases to 88.05 ± 10.04% of pre-dive value at 30 min, then increases to 91.42 ± 10.35% of its pre-dive value (both p < 0.0001). Pachymetry shows a slight variation, but is significantly increased to 101.63 ± 1.01% (p = 0.0159) of the pre-dive value, and returns to control level after 60 min. FMD pre-dive was 107 ± 6.7% (p < 0.0001), but post-dive showed a diminished increase to 103 ± 6.5% (p = 0.0132). The pre-post difference was significant (p = 0.03). Conclusion: Endothelial dysfunction leading to arterial stiffness after diving may explain the reduced SFCT observed, but SCUBA diving seems to have miscellaneous consequences on eye parameters. Despite this clear influence on SFCT, no clear relationship between CSC and SCUBA diving can be drawn.

Choroidal Thickness and Primary Open-Angle Glaucoma-A Narrative Review

The choroid provides the majority of blood flow to the ocular tissues and structures that facilitate the processes of retinal metabolism responsible for vision. Specifically, the choriocapillaris provides a structural network of small blood vessels that supplies the retinal ganglion cells and deep ocular tissues. Similar to retinal nerve fiber layer thickness, choroidal thickness (CT) has been suggested to represent a quantifiable health biomarker for choroidal tissues. Glaucoma is a disease with vascular contributions in its onset and progression. Despite its importance in maintaining ocular structure and vascular functionality, clinical assessments of choroidal tissues have been historically challenged by the inaccessibility of CT biomarker targets. The development of optical coherence tomography angiography and enhanced depth imaging created a framework for assessing CT and investigating its relationship to glaucomatous optic neuropathy onset and progression. Pilot studies on CT in glaucoma are conflicting-with those both in support of, and against, its clinical utility. Complicating the data are highly customized analysis methods, small sample sizes, heterogeneous patient groups, and a lack of properly designed controlled studies with CT as a primary outcome. Herein, we review the available data on CT and critically discuss its potential relevance and limitations in glaucoma disease management.

Risk Factors for Corneal Striae in Eyes After Glaucoma Surgery

PRCIS

Eyes with corneal striae had steeper cornea, induced astigmatism, and higher corneal hysteresis (CH), which implies a relationship between striae, corneal shape, and the cornea's resistance to deformation at low intraocular pressures (IOPs).

BACKGROUND

Anterior corneal striae (ACS) are associated with low IOP. However, the clinical significance of ACS is unclear. Here, we aim to evaluate differences in eyes with striae compared with eyes without striae.

METHODS

Adults with ACS (cases) and without ACS (controls) ≥8 weeks after glaucoma surgery with an IOP ≤10 mm Hg were enrolled. Optical coherence tomography and optical biometry were performed. CH, defined as the difference in pressure between corneal indentation and reformation in response to an air jet, was obtained by the ocular response analyzer. Hypotony maculopathy (HM) was defined as optic disc swelling, vascular tortuosity attributed to hypotony, or clinical presence of chorioretinal folds confirmed on OCT.

RESULTS

One hundred sixteen eyes (76 cases, 40 controls) were included. Cases had a lower IOP compared with controls (6.5±2.3 vs. 8.5±1, P<0.0001). A 1 mm Hg increase in CH increased ACS odds [odds ratio (OR)=1.51, P=0.01]. A 1 D increase in the flattest presurgical and postsurgical corneal power increased ACS odds by 1.83 (P=0.01) and 1.41 (P=0.02), respectively. Astigmatism increased in eyes with ACS by 1.11 D (P<0.001). ACS odds were increased with every 1 minute increase in mitomycin-C duration (OR=1.58, P=0.047) and decreased with the use of topical glaucoma medication (OR=0.62, P=0.03). Visual acuity decreased from logarithm of the minimal angle of resolution 0.22 (20/33 Snellen) presurgery to 0.28 (20/38) postsurgery (P=0.008), independent of ACS. HM occurred in 19% of cases (P=0.05). A higher postsurgical CH increased HM odds (OR=1.8, P=0.003). HM predicted a 0.41 mm decrease in axial length (P<0.0001), independent of IOP.

CONCLUSION

ACS were associated with a steeper cornea, induced astigmatism, and higher CH, suggesting a relationship between striae, corneal shape, and the cornea's ability to resist deformations at lower IOP. CH, HM, and axial length shortening were associated independently of IOP.

[On refraction shift after trabeculectomy]

PURPOSE

To determine the factors affecting the shift of refraction after trabeculectomy.

MATERIAL AND METHODS

The study included 42 patients who were examined prior to trabeculectomy and at the following timepoints: 1 week, 1 month and 3 months after surgery. Examination included tonometry with assessment of corneal biomechanical properties, keratorefractometry with vector analysis, and biometry. The obtained data was processed for regression analysis and to find the possible correlations.

RESULTS

All significant correlations between the measured parameters only occur on week 1. Postoperative spherical component of refraction (sphere) correlates negatively both with preoperative axial length (AL) and anterior chamber depth (ACD) (r=-0.699 and r=-0.458, p<0.05) and postoperative AL and ACD (r= -0.767 and r= -0.415, p<0.011). Dependence of sphere on AL is also expressed as a regression model. The magnitude of AL change depends on the magnitude of intraocular pressure (IOP) change (r=0.729, p<0.0001) and correlates negatively with postoperative IOP (r=-0.454, p=0.009) and baseline corneal hysteresis (CH; r= -0.482, p=0.009). Dependence of AL on IOP is also expressed as a regression model. The magnitudes of sphere and cylinder shifts correlate negatively with each other (r=-0.416, p=0.038). Keratometry reveals that the overall cylinder value correlates with the corneal cylinder, and so do the magnitudes of their shifts (r=0.589 and r=0.574, p<0.0001). Dependence of corneal hysteresis on IOP is expressed as a regression model; however, neither tonometric nor biomechanical corneal properties correlate with refraction.

CONCLUSIONS

Sphere correlates negatively with AL and ACD. In turn, AL is related to the reduction in IOP. This dependence is likely the most important one for the refraction shift after trabeculectomy. No correlations were found for the change of astigmatism.

[Calculation of intraocular lens power after trabeculectomy]

PURPOSE

To assess biometric changes in eyes after trabeculectomy (TE) and its impact on refractive outcomes of phacoemulsification (PE) in order to determine the corrections for calculation of intraocular lens (IOL) power.

MATERIAL AND METHODS

The study included two groups of patients: the 1^st group consisted of 116 patients who were assessed by optical biometry (IOL-Master 500) for mean biometric values before and after TE; the 2^nd group included 31 patients with history of TE (study subgroup) and 47 individuals without glaucoma (control subgroup) who underwent PE with subsequent comparison of IOL calculation accuracy.

RESULTS

There was significant axial length (AL) shortening in the 1^st group from 23.28±0.97 to 23.19±0.97 mm (p<0.001) 6 months after TE, which positively correlated (r=0.296, p=0.001) with intraocular pressure (IOP) decrease (from 25.4±5.34 to 17.2±4.42 mm Hg, p<0.001). Mean keratometry and anterior chamber depth values did not significantly change after TE. Mean IOL power calculation error after PE in the 2^nd group was -0.05±0.47 D and 0.003±0.62 D for the control and study subgroups, respectively (p=0.697). However, significant impact of preoperative IOP on IOL power calculation error was discovered in the study subgroup (R²=0.526, p<0.001), but not in the control subgroup (R²=0.061, p=0.052). Based on linear regression, the expected IOL power calculation errors depending on the preoperative IOP were determined for patients with history of TE.

CONCLUSION

AL shortening due to decrease in IOP in patients with history of TE leads to IOL power calculation errors. Expected IOL calculation error related to preoperative IOP level was determined, which could help improve refractive outcomes of PE in patients with history of TE.

Correlation between choroidal thickness and intraocular pressure control in primary angle-closure glaucoma

Purpose:

To study the correlation between choroidal thickness (CT) and IOP control in primary angle-closure glaucoma (PACG).

Methods:

In total, 61 patients (102 eyes) with PACG underwent subfoveal CT (SFCT) scanning using enhanced depth imaging–optical coherence tomography. The subjects with PACG were further grouped as controlled IOP (≤21 mm Hg on maximal medical therapy) and uncontrolled IOP (>21 mm Hg on maximal medical therapy). The average CT of the PACG eyes was calculated and compared between both groups. A correlation analysis was done between CT and intereye difference in CT with the disease parameters.

Results:

The mean CT was 274.38 ± 42.10 μm in 102 PACG eyes. SFCT was significantly increased in the uncontrolled IOP group as compared with the controlled IOP group. The mean SFCT was 245.57 ± 62.10 μm in the controlled group and 294.46 ± 51.05 μm in the uncontrolled group (P < 0.01). Factors associated with a thicker choroid were younger age, high IOP, and higher optic nerve head cupping (P < 0.001). Neither the visual field-mean deviation (VF-MD) nor pattern standard deviation (PSD) was found to be associated with overall CT. The intereye asymmetry between CT was significantly associated with poor VF-MD and PSD.

Conclusion:

PACG eyes with thicker choroid may be a risk factor for poor IOP control on medical anti-glaucoma therapy. Thicker choroid as compared to the fellow eye is a poor prognostic sign and these eyes should be monitored closely.

A Review of Potential Novel Glaucoma Therapeutic Options Independent of Intraocular Pressure

Glaucoma, a progressive optic neuropathy characterized by retinal ganglion cell degeneration and visual field loss, is the leading cause of irreversible blindness worldwide. Intraocular pressure (IOP) is presently the only modifiable risk factor demonstrated to slow or halt disease progression; however, glaucomatous damage persists in almost 50% of patients despite significant IOP reduction. Many studies have investigated the non-IOP-related risk factors that contribute to glaucoma progression as well as interventions that can prevent or delay glaucomatous neurodegeneration and preserve vision throughout life, independently of IOP. A vast number of experimental studies have reported effective neuroprotection in glaucoma, and clinical studies are ongoing attempting to provide strong evidence of effectiveness of these interventions. In this review, we look into the current understanding of the pathophysiology of glaucoma and explore the recent advances in non-IOP related strategies for neuroprotection and neuroregeneration in glaucoma.

Relationship Between Changes in the Choroidal Structure and Blood Flow of the Macula After Trabeculectomy

Purpose

To elucidate the relationship between changes in the choroidal structure and blood flow of the macula after trabeculectomy.

Methods

A prospective study of 30 eyes of 30 patients with glaucoma who underwent trabeculectomy. Enhanced depth imaging optical coherence tomography with choroidal image binarization and laser speckle flowgraphy of the macula were performed at baseline and 1, 3, and 6 months postoperatively. Mixed-effects models with adjustment for confounders were used to analyze longitudinal changes in the mean choroidal thickness (mCT), mean choroidal vascular thickness (mCVT), mean choroidal interstitial thickness (mCIT), and mean blur rate (MBR).

Results

The decrease in the intraocular pressure (IOP; 45%–51%) and axial length (0.5%–0.8%) and the increase in ocular perfusion pressure (OPP; 34%–38%), mCT (16%–19%), mCVT (16%–20%), mCIT (17%–20%), and MBR (22%–25%) were significant at each postoperative time point (all P < 0.001). In the multivariate analysis, the mCVT changes were positively correlated with the OPP and MBR changes (P = 0.04 and P < 0.001, respectively), whereas the mCIT changes were negatively correlated with IOP changes (P = 0.005). The MBR changes correlated significantly with changes in mCVT but not mCIT (P < 0.001 and P = 0.39, respectively).

Conclusions

Thickness changes in the intraluminal and extraluminal parts of the choroid were closely associated with changes in blood flow and IOP, respectively, although both parts thickened comparably after IOP reduction by trabeculectomy.

Translational Relevance

The choroid reacts to IOP reduction differently between the intraluminal and extraluminal areas, blood flow dependence in the vascular area, and IOP dependence in the stromal area.

Choroidal thickness after phacoemulsification: nonrandomized comparison of postoperative topical ketorolac vs dexamethasone vs combination of ketorolac-dexamethasone eyedrops

PURPOSE

To compare the effect of topical dexamethasone vs ketorolac vs combined dexamethasone-ketorolac after phacoemulsification on choroidal thickness (CT).

SETTING

Tertiary university-based hospital.

DESIGN

Prospective nonrandomized comparative case series.

METHODS

Ninety-two eyes of 92 patients were assigned to the 3 groups after uneventful phacoemulsification: Group 1, dexamethasone; Group 2, ketorolac; Group 3, combined dexamethasone-ketorolac applied topically. CT at subfoveal (SFCT), nasal, and temporal as primary and central retinal thickness (CRT) as secondary outcomes were measured preoperatively and at 1 month, 3 months, and 6 months postoperatively using enhanced depth-imaging optical coherence tomography.

RESULTS

Preoperative CT was similar between the groups (all P > .05). The groups differed in pattern of changes in nasal and temporal CT (both P < .001) although their changes of CRT (P = .13) and SFCT (P = .55) over time were similar. The mean of SFCT at 1 month, 3 months, and 6 months was significantly higher than baseline in dexamethasone (P < .001 for all follow-ups) and combined (P < .001 for both 1 month and 3 months and P = .03 for 6 months) groups, whereas it was not statistically significant in the ketorolac group (P = .07). There was an increase in the nasal and temporal CT in 3 groups, persisted at 6 months in dexamethasone (both P < .001) and ketorolac (both P < .001) groups, whereas the change was not statistically significant at 6 months in the combined group. Choroidal thickness measurements were performed in 31 eyes of 31 patients in group 1, 29 eyes of 29 patients in group 2, and 32 eyes of 32 patients in group 3.

CONCLUSIONS

Dexamethasone and combined groups had statistically significant changes of SFCT after phacoemulsification; however, the ketorolac group did not. The pattern of SFCT changes was similar between 3 groups.

Detecting Progression in Advanced Glaucoma: Are Optical Coherence Tomography Global Metrics Viable Measures?

SIGNIFICANCE

Optical coherence tomography (OCT) summary measures have been suggested as a way to detect progression in eyes with advanced glaucoma. Here, we show that these measures have serious flaws largely due to segmentation errors. However, inspection of the images and thickness maps can be clinically useful.

PURPOSE

This study aimed to test the hypothesis that recently suggested global OCT measures for detecting progression in eyes with advanced progression are seriously affected by segmentation mistakes and other errors that limit their clinical utility.

METHODS

Forty-five eyes of 38 patients with a 24-2 mean deviation worse than -12 dB had at least two spectral domain OCT sessions (0.8 to 4.4 years apart) with 3.5-mm circle scans of the disc and cube scans centered on the fovea. Average (global) circumpapillary retinal nerve fiber layer thickness, GcRNFL, and ganglion cell plus inner plexiform layer thickness, GGCLP, were obtained from the circle and cube scan, respectively. To evaluate progression, ΔGcRNFL was calculated for each eye as the GcRNFL value at time 2 minus the value at time 1, and ΔGGCLP was calculated in a similar manner. The b-scans of the six eyes with the highest and lowest ΔGcRNFL and ΔGGCLP values were examined for progression as well as segmentation, alignment, and centering errors.

RESULTS

Progression was a major factor in only 7 of the 12 eyes with the most negative values of either ΔGcRNFL or ΔGGCLP, whereas segmentation played a role in 8 eyes and was the major factor in all 12 eyes with the largest positive values. In addition, alignment (one eye) and other (three eyes) errors played a secondary role in four of the six eyes with the most negative ΔGcRNFL values.

CONCLUSIONS

For detecting the progression of advanced glaucoma, common summary metrics have serious flaws largely due to segmentation errors, which limit their utility in clinical and research settings.

Immediate Choroidal Expansion after Bleb Needling

The purpose was to report a case of immediate choroidal expansion after a needling procedure. This is a retrospective case report of an 80-year-old male with pseudoexfoliative glaucoma who underwent Xen 45 Gel stent implantation and then trabeculectomy in the right eye. During follow-up, several bleb needling procedures were required to treat bleb fibrosis. Before and after the last bleb needling, spectral-domain optical coherence tomography (SD-OCT) was performed to investigate choroidal changes. SD-OCT was also repeated 1 week later. SD-OCT showed instant choroidal expansion (both in the macular and peripapillary area) that was quite sustained throughout the 1 week-follow-up and after 5 months. Bleb needling can cause immediate choroidal expansion that can be quite sustained throughout several months of follow-up. SD-OCT is essential for detecting choroidal changes.

The Association of Acute Cerebrospinal Fluid Pressure Reduction with Choroidal Thickness

PURPOSE

To investigate the changes in choroidal thickness (CT) after acute cerebrospinal fluid pressure (CSFP) reduction in human subjects.

METHODS

Before and 15 minutes after diagnostic lumbar puncture (LP), 44 patients underwent measurement of CT by swept-source optical coherence tomography. Thirty-two healthy volunteers imitated the body posture of LP procedure and underwent the same measurement before and 15 minutes after body posture change.

RESULTS

After CSFP reduction from 10.9 ± 2.1 mmHg at baseline to 8.1 ± 1.5 mmHg (p < 0.001), CT decreased in subfoveal region (p = 0.005), small to medium vessel layer (SMVL, p < 0.001), peripapillary regions in temporal (p = 0.001), nasal (p < 0.001), superior (p < 0.001) and inferior (p < 0.001), respectively. However, no significant change in CT in the control group after body posture change (all p > 0.05). A significant association between CSFP and the ratio of small to medium vessel layer to total choroidal thickness was found (p = 0.009). The CSFP reduction rate was associated with the change rate of SMVL to total CT portion, for each percent decrease in CSFP was associated with a decrease by 0.22% in the rate of SMVL to total CT portion (R² = 0.125, p = 0.018).

CONCLUSIONS

A significant decrease in subfoveal CT, small to medium vessel layer and peripapillary region were observed following acute CSFP reduction. The CSFP reduction rate was associated with the change rate of small to medium vessel layer to total CT portion.

Reasons why OCT Global Circumpapillary Retinal Nerve Fiber Layer Thickness is a Poor Measure of Glaucomatous Progression

Purpose

To assess the effects of local defects, segmentation errors, and improper image alignment on the performance of the commonly used optical coherence tomography (OCT) measure of progression, that is the change in global (average) circumpapillary retinal nerve fiber layer (cpRNFL) thickness (ΔG).

Methods

One hundred fifty eyes suspected of, or with, early glaucoma had OCT circle and cube scans obtained using eye tracking on two occasions at least 1 year apart. Statistical progression was defined by fixed values of ΔG (3-8 um) and quantile regression. For a reference standard, four authors identified 30 eyes as "likely progressed," and 61 eyes that "likely had not progressed" based on OCT reports from both baseline and follow-up tests.

Results

A ΔG criterion of 4 um had the best accuracy: 77%, with 5 false positive (8.2%) and 16 false negative (53%). A post hoc analysis of circular b-scans and OCT probability maps of these eyes indicated that segmentation errors and local progression accounted for most of these mistakes. Segmentation errors, although less common, were also present in true positives and true negatives.

Conclusions

Local defects and segmentation errors are the primary reasons for the poor performance of cpRNFL thickness G metric. Because these problems are difficult, if not impossible, to eliminate, the G metric should not be relied on in isolation for detecting glaucomatous progression.

Translational Relevance

Local defects and segmentation errors are easily identified by viewing OCT circumpapillary images, which should be part of the standard protocol for detecting glaucomatous progression.

Neuroretinal rim response to transient changes in intraocular pressure in healthy non-human primate eyes

Optic nerve head (ONH) neuroretinal rim thickness, quantified as minimum rim width (BMO-MRW), is a sensitive measure for assessing early glaucomatous disease. The BMO-MRW is sensitive to transient fluctuations in intraocular pressure (IOP), but the time course over which BMO-MRW decreases and recovers with changes in IOP remains unknown. The goal of this study was to investigate the dynamics of BMO-MRW changes over 2-h periods of mild or moderate IOP elevation, and subsequent recovery, in healthy non-human primate eyes. Eight non-human primates were included in the study. For each animal, in two different sessions separated by at least 2 weeks, the anterior chamber IOP of one eye was maintained at either 25 mmHg or 40 mmHg for 2 h and, subsequently, at 10 mmHg for 2 h. For the duration of anterior chamber cannulation, optical coherence tomography (OCT) radial scans centered on the ONH were acquired every 5 min and used to quantify BMO-MRW. An exponential decay or rise to maximum function was used to determine the extent and rate of structural change. Additionally, Bruch's membrane opening (BMO) area, BMO height/displacement, and BMO-referenced anterior lamina cribrosa surface depth (BMO-ALCSD) were computed from radial scans. A circular scan was used to quantify retinal nerve fiber layer thickness (RNFLT) and circumpapillary choroid thickness. The primary results demonstrated that the BMO-MRW changed over an extended duration, while BMO displacement was rapid and remained stable with sustained IOP. The mean maximum predicted BMO-MRW thinning following 2 h of IOP elevation was significantly related to pressure (34.2 ± 13.8 μm for an IOP of 25 mmHg vs 40.5 ± 12.6 μm for 40 mmHg, p = 0.03). The half-life for BMO-MRW thinning was 21.9 ± 9.2 min for 25 mmHg and 20.9 ± 4.2 min for 40 mmHg, not significantly different between IOP levels (p = 0.76). Subsequently, after 2 h of IOP at 10 mmHg, all animals exhibited partial recovery of BMO-MRW with similar degrees of persistent residual thinning for the two IOP levels (21.5 ± 13.7 vs 21.0 ± 12.3 μm, p = 0.88). Similar to BMO-MRW, choroid thickness exhibited gradual thinning with IOP elevation and residual thinning following IOP reduction. However, there was no significant change in BMO area or BMO-ALCSD in either experimental session. The RNFLT gradually decreased over the duration of IOP elevation, with continued decreases following IOP reduction for the 40 mmHg session, resulting in total changes from baseline of -2.24 ± 0.81 and -2.45 ± 1.21 μm for 25 and 40 mmHg, respectively (p < 0.001). The sum of the results demonstrate that the ONH neural tissue is sensitive to changes in IOP, the effects of which are gradual over an extended time course and different for increased vs. decreased pressure. Understanding the duration over which IOP influences BMO-MRW has important implications for studies investigating the effects of IOP on the ONH. Additionally, individual variability in ONH response to IOP may improve our understanding of the risk and progression of disease.

Pulse Waveform Analysis of the Ocular Blood Flow Using Laser Speckle Flowgraphy before and after Glaucoma Treatment

Although reduction in intraocular pressure (IOP) is the principle of glaucoma treatment, impaired ocular blood flow is believed to play a role in the progression of glaucoma. This study evaluated the effect of glaucoma treatment on pulse waveforms for optic nerve head (ONH) microcirculation in patients with glaucoma. Fifty-one subjects were included on the basis of the glaucoma treatment administered, which involved instillation of prostaglandin (PG) analogs (PG group; n = 28) or trabeculectomy (trabeculectomy group; n = 23). ONH blood flow, represented by the mean blur rate (MBR_T) and pulse waveforms, was measured using laser speckle flowgraphy before and 1 and 3 months after treatment. Three months after treatment, IOP exhibited a significant decrease (p < 0.05). Although there was no significant change in MBR_T after treatment, the acceleration time index (ATI) significantly decreased (p=0.034) in the PG group. In the trabeculectomy group, there was no significant change in the MBR_T after treatment, while fluctuation (p=0.019) and blowout score (BOS) (p=0.036) exhibited significant decrease and increase, respectively. Multiple regression analysis showed that mean deviation was significantly associated with the rate of change in the BOS (p=0.013), age was a significant contributing factor for the rate of change in fluctuation in the trabeculectomy group, reflection was significantly associated with the ATI (p=0.037) in the in the PG group. Both glaucoma treatments can change the pulse waveforms, with MBR_T remaining unchanged, and IOP reduction owing to the treatment may contribute to stable blood flow in the tissue area of the ONH. As impaired ocular blood flow plays a role in the progression of glaucomatous damage, it would be beneficial if glaucoma treatment could improve the stability of ONH microcirculation.

Choroidal thickness and intraocular pressure after 25-gauge and 23-gauge vitrectomy for idiopathic epiretinal membrane

PURPOSE

To determine the relationship between the subfoveal choroidal thickness (SCT) and intraocular pressure (IOP) following 25-gauge (25G) and 23-gauge (23G) vitrectomy for idiopathic epiretinal membrane (ERM).

STUDY DESIGN

Retrospective, consecutive, interventional case series.

METHODS

Sixty-two patients undergoing 25G vitrectomy and 56 patients undergoing 23G vitrectomy for ERM participated. SCT was measured using enhanced depth imaging optical coherence tomography and IOP were measured both at baseline and postoperatively.

RESULTS

In both groups, the IOPs on day one and one week after surgery were significantly lower than at baseline (P < 0.001 for both). The rates of changes of IOP were significantly greater in 23G compared to 25G on day one (P = 0.026). In 23G the SCTs on day one and one week after surgery were significantly thicker (P < 0.001) than baseline. The rates of changes in SCT between baseline and day one negatively correlated with those of IOP in 23G (r = -0.559, P < 0.001) but no correlation was observed with 25G (r = -0.129, P = 0.316).

CONCLUSION

Choroidal thickness increases soon after 23G vitrectomy for ERM which is probably due to the transient hypotony, however, early SCT change does not appear in 25G vitrectomy. Twenty-five-gauge vitrectomy may have an advantage in minimizing postoperative choroidal changes.

The clinical features of posterior scleritis with serous retinal detachment: a retrospective clinical analysis

AIM

To summarize the clinical features, systemic associations, risk factors and choroidal thickness (CT) changing in posterior scleritis (PS) with serous retinal detachment.

METHODS

This retrospective study included 23 patients diagnosed PS with retinal detachment from August 2012 to July 2017. All patients' medical history and clinical features were recorded. The examinations included best corrected visual acuity (BCVA), intraocular pressure (IOP), fundus examination, and routine eye examinations. Posterior coats thickness (PCT) was determined by B-scan ultrasound, the CT was measured by enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) and clinical data were compiled and analyzed.

RESULTS

After application of extensive exclusion criteria, 23 patients with PS remained (13 females, 10 males). The average age at presentation was 29.5±9.24 years old. Ocular pain and blurred vision were the two most common complained symptoms by patients. Anterior scleritis occurred in 12 patients, which was confirmed by ultrasound biomicroscopy (UBM) examination. Despite all patients displaying serous retinal detachment in their macula, no fluorescein leakage was observed in the macular area. Optic disc swelling was documented in 10 of the 23 eyes. From B-scan ultrasound examination, the PCT increased with fluid in Tenon's capsule demonstrated as a typical T-sign. The average PCT was 2.51±0.81 mm in the PS-affected eyes and only 1.09±0.29 mm in the unaffected eye (P<0.0001). The subfoveal CT was 442.61±55.61 µm, which correlated with axis length (r=-0.65, P=0.001) and PCT (r=0.783, P<0.001). The BCVA and IOP did not correlate with either CT or PCT.

CONCLUSION

PS with serous retinal detachment presented a variety of symptoms, such as pain, visual loss, and physical indicators. Typical T-sign detected by B-scan ultrasound is a useful confirmatory sign for PS diagnosis. Pathological increases in CT might be a potential predictive factor for inflammation.

Does using topical latanoprost affect subfoveal choroidal thickness?

Purpose: The aim of our prospective study was to investigate the effect of using latanoprost eye drops on subfoveal choroidal thickness in the macular area, as measured by using enhanced depth imaging optical coherence tomography (EDI-OCT). Materials and methods: A total of 39 eyes from 39 patients with bilateral glaucoma or ocular hypertension who had never received hypotensive therapy (study group) and 39 eyes from 39 age- and gender-matched healthy individuals (control group) were included in this study. The EDI-OCT measurements of subfoveal choroidal thickness were obtained during an initial visit before latanoprost therapy and at visits after 1 and 3 months of latanoprost therapy. Results: The mean subfoveal choroidal thickness was 309.5 ± 38.5 µm before latanoprost therapy in the study group and 307.3 ± 31.8 µm in the control group (p = .794). During latanorprost therapy in the study group, mean values of subfoveal choroidal thickness at the initial visit and at intervals of 1 and 3 months were 309.5 ± 38.5 µm, 314.2 ± 39.7 µm, and 318.3 ± 33.4 µm, respectively, which indicated a statistically significant difference between the initial and third visits only (p=.002). Conclusion: Subfoveal choroidal thickness increased after 3 months of topical latanoprost therapy.

Changes in choroidal area following trabeculectomy: Long-term effect of intraocular pressure reduction

Purpose

To evaluate changes in the macula and peripapillary choroidal area at one year after trabeculectomy in order to determine the effect of intraocular pressure (IOP) changes.

Methods

This prospective longitudinal study examined 30 eyes of 30 patients with glaucoma that was uncontrolled by medical therapy. At 1 day before and at 1 year after the trabeculectomy surgery, macular and peripapillary choroidal images were recorded by enhanced depth imaging optical coherence tomography (EDI-OCT). Luminal and interstitial areas were converted to binary images using the Niblack method. Factors influencing the macular choroidal and peripapillary area were examined by multivariate analysis.

Results

After trabeculectomy, the mean IOP was 10.8±3.2 mmHg compared to 17.8±7.2 mmHg at baseline (P < 0.001). The total macular choroidal area after the surgery increased from 317,735±77,380 to 338,120±90,700 μm², while the interstitial area increased from 108,598±24,502 to 119,172±31,495 μm² (all P < 0.05). The total peripapillary choroidal area after the surgery also increased from 1,557,487±431,798 to 1,650,253±466,672 μm², while the interstitial area increased from 689,891±149,476 to 751,816±162,457 μm² (all P < 0.05). However, there were no significant differences observed in the luminal area before and after the surgery. A decrease in the IOP was among the factors associated with the changes in the peripapillary choroidal area.

Conclusions

IOP reductions after trabeculectomy led to increases in the macular and peripapillary choroidal areas for at least 1 year postoperative. Increases in the interstitial areas were the primary reason for observed changes in the choroidal area after trabeculectomy.

Changes in choroidal thickness and optic nerve head morphology after filtering surgery: nonpenetrating deep sclerectomy versus trabeculectomy

Background

The purpose of this study was to evaluate the changes in choroidal thickness and lamina cribrosa position after nonpenetrating deep sclerectomy (NPDS) and trabeculectomy.

Methods

Twenty-three eyes with glaucoma that required filtering surgery were included (12 NDPS and 11 trabeculectomies) in this prospective observational study. OCT-enhanced depth imaging (OCT-EDI) was used to measure choroidal thickness, prelaminar tissue thickness and lamina cribrosa position before and 7 days and 1 month after surgery. All results are shown as median (interquartile range values).

Results

Intraocular pressure (IOP) was significantly lower 1 week after surgery than at baseline (7 (6/10) mmHg vs. 21 (18/26) mmHg; p < 0.001) with a mean 64% decrease. IOP remained significantly lower at 1 month with a 55% mean decrease as compared to baseline (10 (8/12) mmHg; p < 0.001). One week after surgery, the subfoveolar choroidal thickness (SFCT) significantly increased (372 (306/523) μm vs. 317 (227/413) μm; p = 0.04) and the prelaminar tissue (PLT) was significantly thicker (269 (162/360) μm vs. 138 (87/268) μm; p = 0.02) as compared to preoperative measurements. These changes were not statistically significant at one month. There were no differences concerning these parameters between the NPDS and trabeculectomy groups. During the first week, the SFCT increase was correlated with IOP reduction (r = − 0.41; p = 0.04).

Conclusions

OCT-EDI allowed the visualization of structural changes at the level of the optic nerve and choroidal vascularization during acute IOP changes. No difference was observed between NPDS and trabeculectomy concerning these structural modifications.

The association between prelaminar tissue thickness and peripapillary choroidal thickness in untreated normal-tension glaucoma patients

To evaluate the association between prelaminar tissue thickness (PLT) and peripapillary choroidal thickness (PCT) in untreated normal-tension glaucoma (NTG) patients.A cross-sectional study was conducted in 65 untreated NTG patients. All of the subjects were imaged with swept-source optical coherence tomography (SS-OCT, DRI OCT; Topcon, Tokyo, Japan) to obtain the horizontal scan crossing the optic nerve head center. The PLT was calculated by subtracting the anterior prelaminar depth (APLD) from the anterior lamina cribrosa depth (ALCD). The retinal nerve fiber layer thickness and PCT were measured automatically using the in-built automated software of the OCT device. Spearman correlation analysis was conducted to investigate the ocular factors that were associated with PLT.The average PLT, APLD, ALCD, and PCT values were 134.05 ± 55.54, 314.59 ± 113.59, 448.64 ± 125.69, and 121.23 ± 59.56 μm, respectively. PLT was correlated with the axial length, visual field index (VFI), ALCD, and PCT. When the subjects were divided into 2 groups according to their PLT values (median value, 125.114 μm), the thin PLT group showed worse mean deviation, VFI values, and thinner PCT when compared to the thick PLT group.The PLT was significantly associated with the PCT, and the thinner PLT showed the greater glaucomatous damage in untreated NTG. The thickness of the prelaminar tissue may be related with the choroidal blood flow in untreated NTG patients.

Correlation between choroidal thickness and intraocular pressure after 23-gauge vitrectomy for idiopathic epiretinal membrane

AIM

To determine the relationship between the subfoveal choroidal thickness (CT) and intraocular pressure (IOP) following idiopathic epiretinal membrane (ERM) surgery.

METHODS

Retrospective observational case series of patients who had undergone 23-gauge vitrectomy for an ERM. The measurements of CT and IOP were done at the baseline and 1d, 1wk, 1, 3, 6, and 12mo after the surgery.

RESULTS

Forty-four eyes of 43 patients with a mean age of 69.8±9.5y were studied. The CT was 200.8±86.3 µm at the baseline, 210.1±83.5 µm at 1d, 213.2±85.4 µm at 1wk, 203.1±84.0 µm at 1mo, 197.5±85.5 µm at 3mo, 197.7±84.0 µm at 6mo, and 191.2±86.8 µm at 12mo after surgery. The CT on day 1 and week 1 after the surgery was significantly thicker than that at the baseline CT (P=0.0023 and P<0.0001). The CT at 12mo after surgery was significantly thinner than the baseline (P=0.0062). The IOP on day 1 and week 1 were significantly lower than the baseline (P<0.0001 and P=0.0042). The IOP at 1, 3, 6, and 12mo after surgery were significantly higher than the baseline IOP (P=0.0087, P=0.0023, P<0.00051, and P<0.0001). The rates of changes in the CT between baseline and day 1 and week 1 were significantly and negatively correlated with the rates of change in the IOP (P<0.0001 and P=0.046). In the group with the IOP change rate of -30% or less at 1d postoperatively, the change rate of CT was -21.1% to 31.2% (9.8%±12.4%) and in the group of -29% or more, it was -8.9% to 28.0% (2.6%±8.9%). The change rate of CT in the group with the IOP change rate of -30% or less was significantly higher than the group of -29% or more (P=0.016).

CONCLUSION

CT increases soon after the ERM surgery which is probably due to the transient hypotony, showing that IOP may be a significant confounding factor for CT.

Significant hyperopic shift in a patient with extreme myopia following severe hypotonia caused by glaucoma filtering surgery

INTRODUCTION:

To report the case of a high hyperopic refractive shift associated with significant shortening of the ocular axial length following glaucoma filtering surgery.

METHODS:

Case report. Patient's records were consulted retrospectively.

RESULTS:

A 57-year-old woman, highly myopic, with a history of bilateral intraocular refractive surgery in 1998 (phakic lens ZB5M) and bilensectomy in 2011 (phakic intraocular lens extraction plus cataract surgery with pseudophakic intraocular lens implantation), presented with consistently high intraocular pressure. Despite the treatment with different topical antiglaucomatous medications and good compliance, her intraocular pressure values remained consistently above 20 mmHg. In 2016, the patient was submitted for glaucoma filtering surgery and the mini shunt Ex-Press was implanted in both the eyes (3 months between surgeries). On the first postoperative day, the eyes were hypotonic (intraocular pressure of 5 mmHg) and bilateral macular edema was observed. Three days later, the intraocular pressure in both the eyes reached values higher than 6 mmHg (between 6 and 14 mmHg). Five months after the surgery the macular edema resolved and a significant shortening of the axial length and an important hyperopic refractive shift was observed. When comparing the preoperative and postoperative (18 months) measurements, the variation of the axial length was 2.49 mm in the right eye and 2.19 mm in the left eye; the patient refraction (spherical equivalent) shifted 2.50 diopters in the right eye and 1.75 diopters in the left eye.

CONCLUSION:

To the best of our knowledge, we report herein the first documented case of an axial length change of this magnitude after glaucoma filtering surgery.

Changes in choroidal area after intraocular pressure reduction following trabeculectomy

Purpose

To investigate changes of the macular and peripapillary choroidal areas after trabeculectomy.

Methods

This prospective and interventional study examined 74 eyes of 74 patients with glaucoma uncontrolled by medical therapy. Enhanced depth imaging optical coherence tomography (EDI-OCT) recorded macular and peripapillary choroidal images at 1 day before trabeculectomy and at 2 weeks after surgery. The Niblack method was used to covert luminal and interstitial areas to binary images.

Results

At baseline, the mean intraocular pressure (IOP) was 17.6±6.3 mmHg, while it was 6.5±2.9 mmHg after trabeculectomy (P < 0.001). Increases were observed for the macular choroidal area after the surgery, with the total area increasing from 317,853±95,728 μm² to 368,597±104,393 μm², while the luminal area increased from 210,355±73,650 μm² to 249,464±77,195 μm², and the interstitial area increased from 107,498±27,613 μm² to 119,133±31,811 μm² (all P < 0.001). Increases were also observed after the surgery for the peripapillary choroidal area, with the total area increasing from 1,629,440±460,429 μm² to 1,974,289±500,496 μm², while the luminal area increased from 920,141±328,690 μm² to 1,179,843±357,601 μm², and the interstitial area increased from 709,299±153,179 μm² to 794,446±169,029 μm² (all P < 0.001). There was a significant increase in the ratio of the luminal to choroidal area in the macular area (67.2%) and in the peripapillary area (59.1%). Factors associated with the changes in the peripapillary choroidal area included decreases in the diastolic blood pressure and IOP.

Conclusions

A reduction in the IOP after trabeculectomy led to increases in the macular and peripapillary choroidal areas. Observed changes in the choroidal area after trabeculectomy are primarily due to increases in the luminal areas.

Stabilization Time of Anterior Segment Parameters After Trabeculectomy Surgery

OBJECTIVES

To investigate the postoperative changes in the anterior segment parameters by Scheimpflug imaging method in patients undergoing trabeculectomy surgery.

METHODS

This prospective study included 38 phakic eyes of 38 patients with primary open-angle glaucoma who underwent trabeculectomy. Anterior chamber angle (ACA), anterior chamber depth (ACD), anterior chamber volume (ACV), and central corneal thickness (CCT) of the eyes were measured by performing Scheimpflug imaging in preoperative (baseline) and postoperative periods (1st week and 1st, 3rd, and 6th months after the surgery).

RESULTS

Significant differences were observed in all the anterior segment parameters during the postoperative period (P<0.001 for ACA, ACD, and CCT; P=0.001 for ACV). Compared with preoperative values, ACA, ACD, and ACV values decreased and CCT value increased in the 1st postoperative week (P<0.001 for all the parameters). Compared with the 1st postoperative-week values, ACA, ACD, and ACV values significantly increased and CCT value significantly decreased in the 1st postoperative month (P=0.002 for ACV; P<0.001 for ACA, ACD, and CCT). However, no significant differences were observed between the baseline and 1st postoperative-month values (P>0.05 for all the parameters). Moreover, the changes in the anterior segment parameters were not statistically significant after the 1st postoperative month.

CONCLUSIONS

Our results showed that the changes in the anterior segment parameters observed in the early postoperative period after trabeculectomy returned to their baseline values after approximately 1 month after the surgery and remained stable thereafter.

Peripapillary choroidal thickness in untreated normal-tension glaucoma eyes with a single-hemifield retinal nerve fiber layer defect

The aim of this study was to evaluate the regional variations of peripapillary choroidal thickness (PCT) in normal-tension glaucoma (NTG) patients with a retinal nerve fiber layer (RNFL) defect localized to a single superior or inferior hemifield. This is a retrospective, cross-sectional study.Ninety-five NTG patients and 53 normal subjects were divided into 3 groups: 34 eyes with a superior RNFL defect (group A), 61 eyes with an inferior RNFL defect (group B), and 53 normal eyes (group C). The average, quadrant, and clock-hour RNFL thickness (RNFLT) and PCT were measured using spectral-domain optical coherence tomography. Choroidal thickness ratio (CTR) was defined as the ratio of the measured PCT at a quadrant or a clock-hour position to the average PCT of an individual. The PCT, CTR, and RNFLT were compared among 3 groups.The average PCT of NTG patients was thinner compared to that of healthy subjects (154.17 vs. 180.65 μm, P < .001). Although the average, quadrant, and clock-hour PCTs were not different between groups A and B, the CTR at 11 o'clock was significantly lower in group A compared to that of group B. The 11 o'clock CTR was an independent factor for the initial location of a RNFL defect (P = .03).Eyes with NTG showed regional differences in CTR according to the hemisphere location of their initial RNFL damage. Therefore, CTR may be more useful than the absolute PCT value to assess regional PCT differences in eyes with NTG.

Changes in choroidal thickness following trabeculectomy and its correlation with the decline in intraocular pressure

PURPOSE

Evaluate whether there are significant changes in choroidal thickness following trabeculectomy, and how they relate do the decline in intraocular pressure.

METHODS

This was a prospective evaluation of 28 eyes who underwent Moorfields modified trabeculectomy. The choroidal thickness was measured via OCT with enhanced depth imaging, before surgery and 1 day, 1 week and 1 month after surgery. Measurements were taken at the fovea, 1000 µm temporal to the fovea and 1000 µm nasal to the fovea. The relationship between choroidal thickness and intraocular pressure was statistically evaluated.

RESULTS

The mean intraocular pressure before surgery was 25.07 ± 4.64 mmHg; 8.57 ± 3.62 mmHg after 1 day; 10.36 ± 4.39 mmHg after 1 week and 13.71 ± 5.13 mmHg after 1 month. Mean choroidal thickness increased after trabeculectomy with maximal values at 1 week. The largest increase was found at the fovea, with an average before surgery of 253.54 ± 62.01 µm; 286.75 ± 64.20 µm at 1 day, 286.36 ± 63.14 µm at 1 week and 271.00 ± 60.31 µm at 1 month. Increase in choroidal thickness was significant 1 day and 1 week after surgery in the foveal (p = 0.012, p = 0.007) and temporal (p = 0.040, p = 0.000) locations and 1 week postoperatively on the nasal location (p = 0.016). None of them were significant at 1 month after surgery. Preoperative IOP and choroidal thickness were correlated at all macular locations (ρ = 0.449-0.525, p = 0.004-0.016) yet no correlation was found between increase in choroidal thickness and decline in intraocular pressure in the postoperative period.

CONCLUSION

Choroidal thickness appears to increase temporarily after trabeculectomy and these changes were not correlated with the decline in intraocular pressure. Further research is required to fully understand this phenomenon.

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

PURPOSE:

To assess the changes in peripapillary and macular choroidal thickness, and in the lamina cribrosa position following deep sclerectomy.

METHODS:

Prospective study, including 39 eyes with open-angle glaucoma following deep sclerectomy. Choroidal thickness was automatically measured using swept-source optical coherence tomography at four peripapillary locations (superior, temporal, inferior, and nasal) and at the macular area in nine fields plotted with Early Treatment Diabetic Retinopathy Study grid. Optic nerve head was evaluated by Spectralis optical coherence tomography with enhanced depth imaging technology. All measurements were performed preoperatively and at 1 week and 2 months after surgery.

RESULTS:

The mean intraocular pressure significantly decreased 1 week and 2 months after surgery ( p < 0.001). A significant peripapillary choroidal thickening was observed at all locations 1 week postoperatively ( p ≤ 0.002) and in the temporal quadrant 2 months after surgery ( p = 0.027). There was a significant thickening in all macular choroidal thickness measurements at 1 week ( p < 0.001) and 2 months ( p < 0.05), except at subfoveal and inner nasal locations. The mean peripapillary and macular choroid thickness was 22.8% and 19.7% at 1 week and 6.2% and 7.8% at 2 months, respectively. A significant forward lamina cribrosa displacement occurred at every postoperative stage ( p < 0.001). Multivariate analysis showed a significant correlation between the magnitude of intraocular pressure reduction and the anterior lamina cribrosa movement (0.623, p = 0.000) and a negative correlation between the intraocular pressure change and the mean peripapillary and macular choroidal thickening (-0.527, p = 0.002; -0.568, p = 0.002, respectively).

CONCLUSION:

There was a significant reversal lamina cribrosa displacement measured from Bruch's membrane opening reference despite a significant peripapillary choroidal thickening following deep sclerectomy. Both findings were significantly correlated with the change in intraocular pressure.

Extensive Submacular Hemorrhage After Trabeculectomy With Mitomycin C

PURPOSE

We report the occurrence of an extensive submacular hemorrhage after trabeculectomy with mitomycin C in a patient with an occult choroidal neovascular membrane (CNVM).

PATIENTS AND METHODS

A 66-year-old man had a 3-year history of primary open-angle glaucoma in the left eye, which had been treated with topical antiglaucoma medication. The patient had age-related macular degeneration with an occult CNVM, for which he had received 5 intravitreal injections of ranibizumab and 5 intravitreal injections of bevacizumab in the left eye over a 3-year period. As intraocular pressure was not under control in the left eye over a 2-month period, trabeculectomy with mitomycin C was performed.

RESULTS

On the first postoperative day, intraocular pressure was 8 mm Hg with a well-formed bleb in the left eye. However, extensive subretinal hemorrhage was observed, and the patient underwent pneumatic displacement and pars plana vitrectomy to remove the hemorrhage. After 7 months, extensive subretinal fibrosis was observed and visual acuity was low (hand movement only).

CONCLUSIONS

To our knowledge, this is the first report of an extensive submacular hemorrhage after trabeculectomy with mitomycin C in a patient with an occult CNVM.

Excessive scleral shrinkage, rather than choroidal thickening, is a major contributor to the development of hypotony maculopathy after trabeculectomy

Purpose

We previously reported that eyes with hypotony maculopathy (HM) after trabeculectomy (TLE) exhibited more reduction of axial length (AL) than those without HM, suggesting that inward collapse of the scleral wall may contribute to the development of HM after TLE. However, we did not evaluate change in choroidal thickness (CT), which could influence AL measures. We compared the magnitude and rate of AL and CT changes in eyes with and without HM by simultaneously measuring these parameters before and after TLE.

Methods

We enrolled 77 eyes of 77consecutive patients with glaucoma, who underwent TLE between March 2014 and March 2016. Intraocular pressure (IOP), central corneal thickness, keratometry, AL, and CT were measured pre- and postoperatively, up to 6 months. These biometrics were compared in eyes with and without HM.

Results

The 14 patients who developed HM were significantly younger than those who did not. The eyes with HM exhibited significantly reduced AL (2.8%) compared to those without HM (0.7%). There was no significant difference in CT change between the two groups. The rate of AL reduction was significantly correlated with age, postoperative IOP, and preoperative AL. Post-adjustment logistic regression analysis revealed that eyes with AL reduction rate ≥ 2% had 11.67 higher risk for developing HM (95% confidence interval, 1.28–106.6; P = 0.03).

Conclusions

AL reduction rates ≥ 2% were significantly associated with HM. Excessive reduction in AL, which was seen in eyes with HM, was not an artificial measure resulting from choroidal thickening but rather reflected reductions in the anterior-posterior diameter of the eyeball. Inward collapse of the scleral wall leads to redundancy of the chorioretinal tissue, contributing to the development of HM after TLE.

Choroidal thickness changes following cataract surgery using swept source optical coherence tomography

OBJECTIVE

The aim of this study was to assess changes in subfoveal choroidal thickness (SFCT), measured using swept-source optical coherence tomography (SS-OCT), after routine phacoemulsification cataract surgery.

DESIGN

This is a prospective, interventional, controlled study that took place at Shahzad Eye Hospital, Karachi, Pakistan, between February 2015 and January 2016.

PARTICIPANTS

One hundred and one patients who were undergoing routine cataract surgery were recruited. One eye per patient was included. The unoperated fellow eyes acted as controls.

METHODS

Swept-source optical coherence tomography scans were performed preoperatively, 1 week postoperatively, and 1 month postoperatively. Two independent graders evaluated the scans to measure the SFCT. The SFCT was measured and recorded for OCT scans from each visit. The general linear model repeated analysis technique was used to assess data from the 3 different time intervals, and paired t tests were used to assess a statistically significant difference between mean preoperative and postoperative SFCT. Probability values of less than 0.05 were considered to be statistically significant.

RESULTS

The mean preoperative SFCT in the study eye was 272.9 ± 96.2; SFCT was 278.9 ± 101.4 (p = 0.051) and 281.5 ± 105.2 (p = 0.01) at week 1 and month 1, respectively. In the control eyes, the mean measurement of preoperative SFCT was 274.2 ± 98.5; measurements were 273.8 ± 100.7 (p = 0.875) and 277.9 ± 103.1 (p = 0.063) at week 1 and month 1, respectively.

CONCLUSIONS

There was a gradual increase in SFCT at 1 month after cataract removal in the study eyes. The effect was more pronounced in younger individuals and nondiabetic individuals.

Avoiding Complications From Patient Positioning for Intraocular Surgery

Collaboration of the surgical and anesthesia teams for patient positioning is essential to assure patient comfort and safety, preventing systemic and ophthalmic complications. The goals and rationales of positioning for intraocular surgery are discussed including placing the head above the heart, elevating the chin, using a head rest that is sufficiently firm, maximizing anesthesia care team access and minimizing fire risk, and taping the patient's head to the operating table to reduce unexpected movement with intraocular injury.

Changes in macular thickness after trabeculectomy with or without adjunctive 5-fluorouracil

Conflict of interest.

None of the authors have any conflict of interest to declare, financial or otherwise. No financial or other support was received for the study.

Background.

The aim of the study was to assess changes in macular thickness after trabeculectomy in respect to the use of 5-fluorouracil (5-FU) as well as to analyse possible associations between the postoperative changes in macular thickness and intraocular pressure (IOP).

Materials and methods.

The prospective observational study included 106 eyes (100 patients) with glaucoma who underwent trabeculectomy with or without 5-FU. Subsequently 5-FU needling was performed if failure of the filtrating bleb occurred. Macular thickness and the IOP were evaluated before, one week, and six months after the surgery. The mean and sectoral macular thickness was assessed using spectral domain optical coherence tomography.

Results.

The mean (±SD) IOP reduced from 27.71 (±6.88) mmHg at baseline to 18.3 (±8.1) mmHg one week (p < 0.001) and 15.1 (±7.6) mmHg six months (p < 0.001) after trabeculectomy. One week postoperatively, the mean macular thickness increased from 285.19 (±15.98) μm to 288.9 (±16.31) μm (p < 0.001); macular thickening was significant in all subfields (p < 0.001) and correlated positively with IOP reduction (rho = 0.312, p = 0.001 for central subfield). After six months, macula remained thicker only at the central and inner nasal subfields (p < 0.05). The changes in macular thickness were not affected by the use of 5-fluorouracil.

Conclusions.

Trabeculectomy may induce a slight macular thickening which is more pronounced in the early postoperative period. The IOP reduction plays an important role in this process and is associated with thicker postoperative macula. However, the use of adjunctive 5-FU has no influence on macular thickness after glaucoma surgery despite its potential hypotonic, inflammatory and cytotoxic effects.

Intraocular Pressure, Axial Length, and Refractive Changes after Phacoemulsification and Trabeculectomy for Open-Angle Glaucoma

PURPOSE

To compare changes in intraocular pressure (IOP), axial eye length (AEL), and refractive outcome in primary open-angle glaucoma patients undergoing cataract surgery and trabeculectomy in dependence of the sequence of surgeries.

MATERIALS AND METHODS

We retrospectively analysed 48 eyes. The changes in refraction, intraocular pressure, and axial eye length were analysed after surgery. In group A (21 subjects), phacoemulsification was performed before trabeculectomy, and in group B (27 subjects), trabeculectomy was performed before phacoemulsification with a minimum time span between interventions of 6 months.

RESULTS

The reduction in IOP and the decrease in AEL after trabeculectomy were significant after 6 and 12 months postsurgery (p < 0.001 each). The decrease in AEL was 0.42 ± 0.11% at 6 months after surgery and 0.40 ± 0.13% after 12 months from surgery; this decrease in AEL was comparable between the groups. The refractive outcome was significantly different between the groups (group A: 0.35 ± 0.75 dpt, group B: -0.05 ± 0.36 dpt, p = 0.018); in group A, trabeculectomy caused a hyperopic shift of 0.34 ± 0.44 dpt (p = 0.002) at 12 months postsurgery.

CONCLUSION

IOP reduction after trabeculectomy causes AEL shortening. The effect on refractive outcome depends on the sequence of surgeries. Better refractive outcome is achieved if phacoemulsification is performed after trabeculectomy.