Change of retinal nerve fiber layer thickness in various retinal diseases treated with multiple intravitreal antivascular endothelial growth factor

Effect of intravitreal injections due to neovascular age-related macular degeneration on retinal nerve fiber layer thickness and minimum rim width: a cross sectional study

PURPOSE

The present study tested the hypothesis that repeated anti-VEGF injections are associated with reduced retinal nerve fiber layer (RNFL) and minimum rim width (MRW) of the optic nerve head.

PATIENTS AND METHODS

Sixty-six patients with a history of intravitreal injections due to neovascular age-related macular degeneration were included. RNFL and MRW were measured using optical coherence tomography (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany).

RESULTS

Mean global RNFL was 90.62 μm and both RNFL as well as MRW significantly decreased with advanced age (p = 0.005 and p = 0.019, respectively). Correlating for the number of injections, no significant impact on RNFL was found globally (p = 0.642) or in any of the sectors. In contrast, however, global MRW was significantly reduced with increasing numbers of intravitreal injections (p = 0.012). The same holds true when adjusted for the confounding factor age (RNFL p = 0.566 and MRW p = 0.023).

CONCLUSION

Our study shows that repeated intravitreal injections due to choroidal neovascularization seem to have a deleterious effect on MRW but not on RNFL. This suggests that MRW is a more sensitive marker than RNFL for evaluating the effect of frequent intravitreal injections on the optic nerve head since it seems to be the first structure affected.

Effect of Repeated Intravitreal Injections in Glaucoma Spectrum Diseases

Purpose

To evaluate whether repeated intravitreal injections (IVI) with an anti-vascular endothelial growth factor (anti-VEGF) agent are associated with glaucomatous progression in eyes with glaucoma spectrum diseases (GSD).

Methods

Single-center, retrospective, longitudinal study of patients with bilateral and similar GSD who: (1) received ≥8 IVI in only one eye during the study period; (2) had ≥2 retinal nerve fiber layer thickness (RNFL) measurements obtained by spectral-domain optical coherence tomography (SD-OCT) at least 12 months apart. The primary outcome was the absolute RNFL thickness change, comparing injected and fellow uninjected eyes. Linear mixed effects models were constructed, including a multivariable model.

Results

Sixty-eight eyes from 34 patients were included, 34 injected and 34 fellow uninjected eyes. Average baseline age was 67.68±21.77 years with a follow-up of 3.66±1.89 years and 25.12±14.49 IVI. RNFL thickness decreased significantly from 80.92±15.78 to 77.20±17.35 μm (p<0.001; -1.18±1.93 μm/year) in injected eyes and from 79.95±17.91 to 76.61±17.97 μm (p<0.001; -1.07±0.98 μm/year) in uninjected eyes. In a multivariable linear mixed model of injected eyes, only higher baseline RNFL thickness (p < 0.001) significantly predicted higher absolute RNFL thickness loss. Neither absolute RNFL thickness variation (p=0.716) nor RNFL rate (p=0.779) was significantly different between paired injected and uninjected eyes. Absolute IOP variation was not significantly different between groups (16.62±4.77 to 15.09±4.34 mmHg in injected eyes and 17.68±5.01 to 14.50±3.39 mmHg in fellow uninjected eyes; p=0.248). The proportion of eyes receiving glaucoma medical treatment increased significantly in both groups (55.9% to 76.5% in injected eyes; p=0.039; 58.8% to 76.5% in uninjected eyes; p = 0.031). The number of glaucoma medications also increased significantly in both groups (1.03±1.11 to 1.59±1.18 glaucoma medications in injected eyes; p=0.003; 1.09±1.11 to 1.56±1.19 glaucoma medications in uninjected eyes; p=0.003).

Conclusion

Repeated IVI do not seem to accelerate glaucomatous progression. Future studies with a longer follow-up are needed.

Short-term Effect of Macular Edema on the Peripapillary Retinal Nerve Fiber Layer in Patients with Wet Age-Related Macular Degeneration and Diabetic Macular Edema: A Comparative Study

BACKGROUND

The combined presence of glaucoma and age-related macular degeneration (ARMD), or glaucoma and diabetes mellitus (DM), occur fairly frequently, especially in elderly patients. This study was intended to compare the effect of resolving macular edema due to DM and wet ARMD on peripapillary retinal nerve fiber layer (RNFL) thickness.

METHODS

This cross-sectional study included 76 patients with macular edema secondary to DM (n = 40, 52.6%) or wet ARMD (n = 36, 47.4%). The control group was comprised of 34 age and sex-matched healthy subjects. All study participants underwent evaluation of central macular thickness (CMT) and the peripapillary RNFL using spectral domain-optical coherence tomography (SD-OCT). Data from eyes that received an anti-VEGF injection were obtained one month after the procedure and were compared with pre-injection data.

RESULTS

The average initial thickness of the global peripapillary RNFL was 98.9 ±16.7 (61-163) µm in the macular edema group and 92.0±16.0 (84-115) µm in the control group (p = 0.045). The post-injection global peripapillary RNFL thickness was 97.3 ±19.0 (61-163) µm in the macular edema group and 92.2±18.0 (81-126) µm in the control group (p = 0.187). In the DM group, the changes in global RNFL thickness, as well as central and temporal quadrant thicknesses, were found to correlate significantly with the change in CMT (r = 0.356, p = 0.024; r = 0.545, p < 0.001, respectively).

CONCLUSIONS

Macular edema in wet ARMD appeared not to affect RNFL thickness. Differences in the etiology of macular edema can have varied effects on peripapillary RNFL. It is recommended that peripapillary RNFL thickness be evaluated cautiously in DM patients receiving intravitreal anti-VEGF therapy.

Short-term effect of intravitreal brolucizumab injections in patients with neovascular age-related macular degeneration on retinal nerve fiber layer thickness

This study reported the short-term effects of intravitreal brolucizumab (IVB) on peripapillary retinal nerve fiber layer (RNFL) thickness in patients with neovascular age-related macular degeneration (nAMD). This retrospective observational case series included patients with nAMD treated with other anti-vascular endothelial growth factor (anti-VEGF) agents and subsequently switched to IVB because of poor response to those other agents on spectral domain optical coherence tomography (SD-OCT). Best-corrected visual acuity (BCVA), intraocular pressure, funduscopy, and SD-OCT were assessed at baseline, 2 weeks, 1 month, and 3 months after injection. Twenty-two patients were included in the study. In the IVB group, BCVA significantly improved 3 months after injection compared with baseline (0.45 ± 0.25 vs. 0.38 ± 0.25, p = 0.012). During the 3-month follow-up, compared with baseline, RNFL thicknesses of the global, superior temporal, inferior temporal, inferior nasal, nasal, and superior nasal sectors did not change substantially in the IVB group. However, temporal RNFL thickness significantly decreased at 1 month (p = 0.045), and the significance was lost at 3 months (p = 0.378). The central macular thickness of treated eyes significantly decreased compared with the baseline at every follow-up visit. IVB in patients with nAMD had morphological and functional visual gain effects without RNFL thinning during the short-term follow-up.

Analysis of ganglion cell-inner plexiform layer thickness in retinal vein occlusion with resolved macular edema

PURPOSE

To analyze the retinal ganglion cell-inner plexiform layer (GCIPL) changes in retinal vein occlusion (RVO) eyes with resolved macular edema using optical coherence tomography.

METHODS

We compared the average and minimum GCIPL thickness in RVO eyes with fellow eyes and healthy controls including 40 unilateral RVO patients and 48 healthy subjects. The average GCIPL thickness in BRVO eyes was segmented into the affected and opposite area according to the site of lesion, comparing them with corresponding areas in fellow eyes. Furthermore, maximum central macular thickness (CMT), visual acuity (VA), and intravitreal injection times were recorded to investigate their relationship with the GCIPL thickness.

RESULTS

Despite no significant difference in CMT (P = 0.96), the average (P = 0.02 and P < 0.001, respectively) and minimum (both P < 0.001) GCIPL thicknesses were decreased in RVO eyes with resolved macular edema after treatment in comparison to fellow eyes and healthy eyes. Maximum CMT thickness was negatively correlated with the minimum GCIPL thickness (r = - 0.47, P = 0.003). VA and average GCIPL thickness were associated (r_s = - 0.49, P = 0.002). In a subgroup analysis that only included BRVO patients, the opposite area revealed no significant difference between two eyes (P = 0.91) although the affected area in BRVO eyes was decreased (P < 0.001).

CONCLUSIONS

A decrease of GCIPL thickness in RVO was observed even after anatomic restoration and associated with VA prognosis. These GCIPL defects could be attributable to systemic risks and RVO itself, not anti-VEGF effects.

Influence of Multiple Anti-VEGF Injections on Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Thickness in Patients with Exudative Age-Related Macular Degeneration

Backgrounds and Objectives: To analyze the influence of multiple anti-VEGF intravitreal injections for exudative age-related macular degeneration on the thickness of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GC + IPL) using spectral domain optical coherence tomography (SD-OCT). Materials and Methods: A prospective interventional study of consecutive patients treated with intravitreal bevacizumab (IVB) was performed. Average and sectorial values of RNFL and GC + IPL thickness were recorded using Cirrus SD-OCT at 0, 6, 12, and 24 months. Patients suffering from any ocular disease that could affect RNFL or GC + IPL thickness were excluded. Results: A total of 135 patients (70 women and 65 men, aged 65 ± 15 years) were included. The average number of injections per patient was 12.4 ± 2.4. Average RNFL and GC + IPL thickness prior to the first injection (87.6 ± 12.2 and 47.2 ± 15.5 respectively), and after 24-month follow-up (86.2 ± 12.6 and 46.7 ± 11.9 respectively) did not differ significantly (p > 0.05). There was a significant decrease in GC2, GC5 segments, and minimum GC + IPL thickness. Conclusion: Repeated anti-VEGF treatment did not cause significant changes in the thickness of RNFL and GC + IPL layers over a period of 24 months. The detected decrease in GC2 and GC5 sectors, as well as in minimum GC + IPL thickness, could be a sign of ganglion cell damage induced by the treatment or could occur during the natural course of the disease.

Prophylactic intraocular pressure lowering measures in anti-vascular endothelial growth factor therapy: A systematic review and meta-analysis

Acute intraocular pressure (IOP) elevation following repeat intravitreal anti-vascular endothelial growth factor (VEGF) injections (IVI) may pose a risk to the integrity of the retinal nerve fiber (RNFL). This meta-analysis investigates the role of IOP-lowering interventions such as an anterior chamber paracentesis (ACP) and IOP-lowering medications on the IOP in patients undergoing IVIs. MEDLINE, EMBASE, and the Cochrane Library were searched up to February, 2021. Studies investigating IOP-lowering interventions in patients undergoing IVI versus controls were included. The primary outcome was the IOP in the short- and long-term post-IVI. Secondary outcomes were changes in the RNFL thickness and best corrected visual acuity (BCVA). ACP at time of anti-VEGF injection significantly lowered IOP immediately post anti-VEGF (WMD: -27.98 mm Hg, P < 0.001). Patients in the ACP group also had significantly thicker RNFL compared to control (WMD: 2.07 um, P < 0.00001) at median follow-up of 16.5 months. IOP-lowering medications (on the day of injection or in the long-term) significantly reduced IOP up to 30 minutes after injection (WMD: -3.31 mm Hg, P = 0.003). This effect was statistically significant between the 2 arms up to 1 month follow-up. There was no difference in BCVA in intervention versus controls. ACP reduces immediate IOP spikes post-IVI and preserves the RNFL in the short- and longterms IOP-lowering medications also reduce IOP spike, with limited data on RNFL thickness.

Risk, Prevalence, and Progression of Glaucoma in Eyes With Age-Related Macular Degeneration Treated With Intravitreal Anti-Vascular Endothelial Growth Factor Injections

PURPOSE

To examine the risk, prevalence, and progression of glaucoma development in age-related macular degeneration (AMD) eyes receiving intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections compared to controls.

DESIGN

Retrospective clinical cohort study.

METHODS

Retrospective review of eyes receiving intravitreal anti-VEGF injections from January 1, 2004, to December 31, 2013, for exudative AMD. Age- and sex-matched control groups of eyes included eyes with nonexudative AMD (NEAMD) and no AMD. Eyes with a diagnosis of glaucoma or glaucoma suspect were reviewed for injection details, type and date of glaucoma diagnosis, glaucoma treatments, standard automated perimetry (SAP), and spectral domain optical coherence tomography (SD-OCT). Qualitative progression was determined by indication of glaucoma progression in provider notes. Quantitative progression was assessed based on change in mean deviation (MD) on SAP, retinal nerve fiber layer thickness on SD-OCT, and intraocular pressure (IOP).

RESULTS

There were 707 eyes of 504 patients treated with anti-VEGF injections and 1008 eyes in the NEAMD and no-AMD cohorts. There was no difference in glaucoma or suspect prevalence at initial presentation between eyes treated with injections and NEAMD (6.9% vs 9.7%, P = .22) or no-AMD controls (vs 8.5%, P = .55). There was no difference in cumulative 5-year probability of new glaucoma diagnosis after anti-VEGF injections compared to NEAMD (1.9% vs 1.0%, P = .69) or no-AMD controls (vs 1.6%, P = .88). There was no difference in qualitative progression of glaucoma in the injection cohort vs NEAMD (P = .19) or no-AMD controls (P = .61). The rate of MD change in injection eyes was similar to NEAMD eyes (P = .74) but greater than no-AMD eyes (P = .02). Eyes receiving injections required more topical glaucoma medications compared with NEAMD (P = .03) and more glaucoma laser treatments compared with no-AMD controls (P = .009). Eyes receiving injections did not require more frequent incisional glaucoma surgery compared with NEAMD (21.0% vs 15.0%, P = .95) or no-AMD controls (vs 10.0%, P = .10).

CONCLUSION

Eyes treated with intravitreal anti-VEGF injections for exudative AMD did not have increased risk of developing glaucoma compared with controls. Of those with a glaucoma diagnosis, exudative AMD eyes receiving injections required a greater number of topical glaucoma medications compared with NEAMD eyes and had a greater rate of MD loss than no-AMD controls.

VEGF-mediated angiogenesis in retinopathy of prematurity is co-regulated by miR-17-5p and miR-20a-5p

The microRNAs miR-17-5p and miR-20a-5p play important roles on angiogenesis; however, it is arguable whether they regulate the formation of retinal blood vessels in retinopathy of prematurity (ROP). We used a mouse model of oxygen-induced retinopathy (OIR) to simulate the development of retinas in mice suffering from ROP, and the expression levels of miR-20a-5p, miR-17-5p, hypoxia-inducible factor 1-alpha (HIF-1α), and vascular endothelial growth factor (VEGF) were measured by RT-qPCR and Western blotting. Cell proliferation, apoptosis, and angiogenesis in the OIR model mice were measured using MTT assays, flow cytometry, and Matrigel assays, respectively. The interaction between HIF-1α/VEGF and miR-20a-5p/miR-17-5p were further validated using dual-luciferase reporter assays, biotin-labeled RNA-pulldown, and RNA immunoprecipitation (RIP) assays. In our OIR model, retinal angiogenesis in the mice was associated with down-regulation of miR-20a-5p and miR-17-5p, as well as up-regulation of HIF-1α and VEGF. In addition, the miR-20a-5p and miR-17-5p inhibited cell proliferation and angiogenesis through regulating HIF-1α and VEGF in the retinal cells of the OIR model mice. Moreover, it was found that miR-20a-5p and miR-17-5p bind to HIF-1α and VEGF at the 3'UTR, and there was a combined effect between miR-20a-5p and miR-17-5p on the regulation of HIF-1α and VEGF. It is worth noting that miR-17-5p and miR-20a-5p can preferentially regulate HIF-1α, then act on VEGF, thereby affecting the angiogenesis associated with ROP.

The Effect of Acute Rises in Intraocular Pressure after Intravitreal Bevacizumab Injection on the Peripapillary Retinal Nerve Fiber Layer Thickness and the Role of Anterior Chamber Paracentesis

Purpose:

To evaluate acute changes in intraocular pressure (IOP) and their short-term effects on the peripapillary retinal nerve fiber layer (RNFL) thickness after intravitreal bevacizumab (IVB) injection.

Methods:

Fifty-eight eyes of 37 patients with treatment-naïve diabetic macular edema or exudative age-related macular degeneration were included in the study. Patients were divided into two groups, and the participants of each group received 3 monthly injections of IVB. IOP was measured right before the injection, immediately after the injection, and 5 min and 20 min after each injection. Peripapillary, RNFL thickness was measured before the injection and 1 month after the third injection. In the second group, anterior chamber (AC) paracentesis was performed before IVB injection.

Results:

IOP values after injection in all sessions were significantly higher in the first group (P < 0.001). The peripapillary RNFL thickness changes 1 month after the third injection was not statistically significantly different in each group (P = 0.816 and 0.773 for the first and second groups, respectively).

Conclusion:

AC paracentesis is an effective modality to reduce the acute rise in IOP. The effect of acute IOP elevation on the peripapillary RNFL thickness was not statistically significant.

Rates of RNFL Thinning in Patients with Suspected or Confirmed Glaucoma Receiving Unilateral Intravitreal Injections for Exudative AMD

PURPOSE

This study evaluated whether the rate of retinal nerve fiber layer (RNFL) thinning is faster in eyes receiving intravitreal injections than in fellow uninjected eyes among patients suspected of having or confirmed to have glaucoma and exudative age-related macular degeneration (AMD).

DESIGN

Retrospective comparative cohort study.

METHODS

Patients with a diagnosis of unilateral exudative AMD and confirmed to have or suspected of having glaucoma in both eyes receiving unilateral intravitreal injections were identified. Those with ≥3 RNFL optical coherence tomography scans and ≥6 injections were included in the study. Rates of RNFL thinning in the injected eye versus the uninjected eye were estimated using linear mixed models. The main outcome measurement was the differences in rates of RNFL thinning in the injected versus the fellow uninjected eye. The effects of postinjection elevation of intraocular pressure (IOP), injection frequency, and number of injections were also evaluated.

RESULTS

A total of 53 patients met the inclusion criteria, receiving 26.4 ± 15.9 intravitreal injections. The average rate of RNFL thinning in uninjected eyes was -0.620 μm/year (P = .029). Injected eyes had an additional incremental loss of -0.385 μm/year, but this value was not statistically significant (95% confidence interval [CI]: -1.147 to 0.379 μm/year; P = .324). Subgroup analysis with only glaucoma patients (n = 33) also demonstrated a nonsignificant effect of injections (-0.568 μm/year; 95% CI: -1.454 to 0.319 μm/year; P = .212). Postinjection IOP elevation, injection frequency, and total number of injections were not associated with faster RNFL loss.

CONCLUSIONS

Among exudative AMD patients with glaucoma or suspected of having glaucoma, the rate of RNFL thinning in eyes receiving intravitreal injections did not significantly differ from that of fellow uninjected eyes.

Changes in the Ganglion Cell-inner Plexiform Layer after Consecutive Intravitreal Injections of Anti-vascular Endothelial Growth Factor in Age-related Macular Degeneration Patients

Purpose

To investigate the effect of intravitreal anti-vascular endothelial growth factor (VEGF) injections on ganglion cell-inner plexiform layer (GCIPL) thickness in patients with age-related macular degeneration (AMD).

Methods

This retrospective study included patients with continuous anti-VEGF treatment who were administered at least three consecutive injections for unilateral neovascular AMD. The GCIPL thickness of the study eyes was compared before and after treatment and with healthy fellow eyes using spectral-domain optical coherence tomography. We also evaluated best-corrected visual acuity, age, and intraocular pressure.

Results

In total, 96 eyes of 48 patients (14 females and 34 males; mean ± standard deviation [SD] age, 70.10 ± 8.89 years) with mean number of 6.29 (SD ± 3.76) anti-VEGF injections and a mean follow-up period of 24.93 months (SD ± 19.86) were included in the study. After three consecutive intravitreal injections of anti-VEGF, the mean GCIPL thickness was significantly reduced from 70.50 (SD ± 14.06) to 65.97 (SD ± 13.91) µm. Borderline or nonsignificant decrease was also observed in GCIPL thickness for each sector. At the end of the study, the mean GCIPL thickness was further reduced to 62.56 (SD ± 16.30) µm, and significant decreases were also observed in all other sectors compared with baseline.

Conclusions

It has been observed that GCIPL thickness can decrease with only three consecutive anti-VEGF injections as well as with long-term treatment in AMD patients.

Effect of intravitreal ranibizumab and aflibercept injections on retinal nerve fiber layer thickness

The purpose is to evaluate the effects of multiple intravitreal ranibizumab (IVR) and aflibercept (IVA) injections on peripapillary retinal nerve fiber layer (RNFL) thickness in patients with exudative age-related macular degeneration (AMD). This retrospective, observational, consecutive case series study enrolled patients newly diagnosed with monocular exudative AMD from January 2014 to October 2019 who were administered IVR or IVA injections. Normal fellow eyes were included as controls. Medical records and spectral domain optical coherence tomography results were reviewed at baseline and at 3, 6, and 12 months after injection. No statistically significant differences in peripapillary RNFL thickness and intraocular pressure were observed between the treated and fellow eyes in the two groups. The global RNFL thicknesses for the treated eyes decreased significantly after 12 months compared with baseline, but no significant difference was observed in any of the six examined sectors (temporal, superior temporal, superior nasal, nasal, inferior nasal, and inferior temporal). At 12 months, the central macular thickness of the treated eyes decreased significantly. Multiple IVR and IVA injections are apparently safe considering peripapillary RNFL damage in patients with exudative AMD. The decreased RNFL thickness of the global sector was presumably due to anatomical improvement of macular lesions.

Birth Weight Is a Significant Predictor of Retinal Nerve Fiber Layer Thickness at 36 Weeks Postmenstrual Age in Preterm Infants

PURPOSE

To assess retinal nerve fiber layer (RNFL) thickness in preterm infants.

DESIGN

Prospective observational study.

METHODS

We imaged 83 awake infants (159 eyes) at 36 ± 1 weeks postmenstrual age (defined as the time elapsed between the first day of the last maternal menstrual period and the time at imaging) using a handheld optical coherence tomography (OCT) system at the bedside. Blinded graders semi-automatically segmented RNFL in the papillomacular bundle (-15 to +15° relative to the fovea-optic nerve axis). We correlated RNFL thickness and 7 characteristics of interest (sex, race, ethnicity, gestational age, birth weight, stage of retinopathy at prematurity, and presence of pre-plus or plus disease) via univariable and multivariable regressions.

RESULTS

RNFL was 3.4 μm thicker in the right eyes than in the left eyes (P < .001). Among 7 characteristics, birth weight was the only independent predictor of RNFL thickness (P < .001). A 250-g increase in birth weight was associated with 5.2 μm (95% confidence interval: 3.3-7.0) increase in RNFL thickness. Compared with very preterm infants, extremely preterm infants had thinner RNFL (58.0 ± 10.7 μm vs 63.4 ± 10.7 μm, P = .03), but the statistical significance disappeared after adjustment for birth weight (P = .25). RNFL thickness was 11.2 μm thinner in extremely low birth weight infants than in very low birth weight infants (55.5 ± 8.3 μm vs. 66.7 ± 10.2 μm; P < .001). The difference remained statistically significant after adjustment for gestational age.

CONCLUSION

Birth weight is a significant independent predictor of RNFL thickness near birth, implying that the retinal ganglion cells reserve is affected by intrauterine processes that affect birth weight.

Segmenting OCT for detecting drug efficacy in CRAO

PURPOSE

Thinning of the inner layers of the retina occurs in patients with central retinal artery occlusion (CRAO). The mechanism for such thinning may be partially due to proteolysis by a calcium-activated protease called calpain. Calpain inhibitor SNJ-1945 ameliorated the proteolysis in a past series of model experiments. The purposes of the present retrospective study were to: 1) use segmentation analysis of optical coherence tomography (OCT) images to mathematically model the loss of specific retinal layers in CRAO patients, and 2) predict the number of patients and days of observation needed for clinical trials of inhibitors against CRAO.

METHODS

A retrospective case control study was conducted by computer-aided search for CRAO (ICD10 H43.1) with at least one OCT procedure (CPT: 92134) in the OHSU Epic patient data base.

RESULTS

After initial swelling, thinning of the inner retinal layers, especially the ganglion cell (GCL) layer followed exponential decay curves. Using sample size statistics and GCL thickness as a marker in a 30-day clinical trial, 19 eyes/group could theoretically detect a 20% beneficial effect of an inhibitor against CRAO. Other markers, such as the whole retinal thickness and combined inner layers could also be used as less-specific markers.

CONCLUSIONS

Using thickness changes in the GCL layer to monitor the efficacy of potential inhibitors against CRAO is practical in human trials requiring a reasonable number of patients and relatively short trial period.

TRANSLATIONAL RELEVANCE

Measurement of GCL thickness would be a useful indicator of CRAO progression in a clinical trial of putative inhibitors.

Comparison of intravitreal anti-vascular endothelial growth factor agents and treatment results in Irvine-Gass syndrome

AIM

To compare the efficacy of bevacizumab, ranibizumab, and aflibercept in pseudophakic cystoid macular edema (CME) patients with Irvine-Gass syndrome (IGS).

METHODS

This study is designed as retrospective consecutive case series. Those who developed postoperative pseudophakic CME that refractory to topical treatment and were treated with anti-vascular endothelial growth factor (VEGF) agents included in the study. Optical coherence tomography (OCT) examination including central macular thickness (CMT), total macular volume (TMV), retinal nerve fiber layer (RNFL), ganglion cell layer (GCL) and choroidal thickness (ChT) measurements at the baseline, 1^st, 3^rd and 6^th month controls were performed.

RESULTS

Fifty-nine eyes of 59 patients with CME and other healthy eyes of the patients (Control group) were evaluated. There were 22 eyes of 22 patients in the bevacizumab group (group 1), 19 eyes of 19 patients in the ranibizumab group (group 2), and 18 eyes of 18 patients in the aflibercept group (group 3). There was no difference in terms of age, gender, axial length, IOP, and spherical equivalent values. The baseline subfoveal and mean ChT were higher in the IGS group. The difference between the baseline and sixth month values of subfoveal and mean ChT were compared in the CME groups, thinning was observed in all three groups. GCL was thinner in the patient group at the 6th month of treatment. The resolution time of CME was observed faster in group 1.

CONCLUSION

All three anti-VEGF agents seem to be effective in CME but bevacizumab appears to be slightly more cost-effective than the other two alternatives.

Relief of Cystoid Macular Edema-Induced Focal Axonal Compression with Anti-Vascular Endothelial Growth Factor Treatment

Purpose

To evaluate the mechanical compression of retinal nerve fiber layer (RNFL) by intraretinal cysts in macular edema and its relief with anti-vascular endothelial growth factor (anti-VEGF) treatment.

Methods

Optical coherence tomography scans were used to measure RNFL thickness and reflectance at seven preselected points at and around the peak of the edema before and after anti-VEGF treatment in 10 patients (11 eyes) with branch retina vein occlusion (BRVO) and diabetic macular edema (DME). Scans through nonedematous retina and from the fellow eyes were taken as controls. Correlations were sought between the changes in retinal and RNFL thickness, RNFL reflectance, and the size of the intraretinal cysts.

Results

Postinjection RNFL thickness decreased significantly only at peak point of the edema (18.1 ± 2.7 vs. 13.8 ± 1.2 µm; P = 0.038), at its nasal edge (20.1 ± 2.7 vs. 15.5 ± 1.4 µm; P = 0.026), and 500 µm away from its nasal border (35.7 ± 6.0 vs. 20.1 ± 2.7 µm; P = 0.006) suggesting focal stagnation of the axoplasmic flow owing to compression at its peak point. Significant postinjection decreases in RNFL reflectivity were also noted at peak point of the cyst (164.9 ± 10.3 vs. 141.5 ± 12.6 arbitrary units [AU]; P = 0.037), at its nasal edge (166.8 ± 7.8 vs. 135.1 ± 10.2 AU; P = 0.02), and 1500 µm away from temporal edge (160.2 ± 6.2 vs. 141.1 ± 6.4 AU; P = 0.022). Cyst proximity to RNFL (D₅₀ = 50 µm) was the only determinant significantly affecting the magnitude of the RNFL thickness change after anti-VEGF treatment (P = 0.001).

Conclusions

Intraretinal cysts due to BRVO and DME locally compress overlying axons and induce anatomic changes suggestive of axoplasmic stagnation. This compression can be relieved with anti-VEGF treatment.

Translational Relevance

Focal compression of RFNL by retinal cysts may indicate a need for early treatment of macular edema to prevent axonal loss, especially in patients with low axonal reserve

The effects of intravitreal injections on intraocular pressure and retinal nerve fiber layer: a systematic review and meta-analysis

The number of eye diseases treated with intravitreal injections is increasing. Obviously, an injection of fluid into the eye results in an increase of intraocular pressure (IOP), the main risk factor for glaucoma. However, the effect of these repeated IOP increases on the eye is unclear. Therefore, we performed a systematic review with meta-analyses. PubMed, Embase and Clinical Trials Registries were searched for articles investigating the relationship between intravitreal injections (anti-vascular endothelial growth factor [anti-VEGF] or steroids) and either IOP, retinal nerve fiber layer (RNFL)-thickness and glaucoma. Multiple meta-analyses were performed, combining data on intravitreal injection of anti-VEGF medication and dexamethasone implants. A total of 74 articles were eligible for meta-analyses. The short-term effect of an intravitreal injection of anti-VEGF showed a statistically significant increase in IOP. One day after injection of anti-VEGF, however, IOP was significantly lower than baseline. The long-term time-intervals showed no significant difference in IOP. After intravitreal injection of a dexamethasone implant, IOP was significantly higher than baseline 1 month post-injection. RNFL-thickness was significantly reduced 6 and 12 months post-injection of anti-VEGF, as well as at end of follow up. Caution is advised when using intravitreal medication, especially when treating patients with advanced glaucoma; in these cases, prophylactic IOP-lowering medication may be considered.

Effect of Intravitreal Injections on Retinal Imaging Metrics in Glaucomatous and Non-Glaucomatous Eyes

Purpose of Review

To summarize the available literature on retinal imaging metrics in the context of intravitreal injections in glaucomatous and non-glaucomatous eyes.

Recent Findings

The retinal nerve fiber layer (RNFL) in injected non-glaucomatous eyes appears to thin at a similar rate to uninjected fellow eyes. A total of four studies evaluating RNFL thinning in injected glaucomatous eyes yielded mixed results, with more recent longitudinal investigations suggesting a potential association. The ganglion cell-inner plexiform layer is also being studied as a potential endpoint in both glaucomatous and non-glaucomatous eyes following intravitreal injections.

Astragalus root extract inhibits retinal cell apoptosis and repairs damaged retinal neovascularization in retinopathy of prematurity

Since the functions of Astragalus root extract in retinopathy remain to be unraveled, this study is performed to elucidate whether Astragalus root extract functions in retinal cell apoptosis and angiogenesis in retinopathy of prematurity (ROP). Newborn mice were selected for establishing mice models of oxygen-induced retinopathy (OIR), which were treated with high-, medium- or low-Astragalus root extract. Evans Blue (EB) was perfused to detect the blood retinal barrier. Additionally, the vascular morphology, number of endothelial cell nuclei of neovascularization, proliferation of blood vessels, ultrastructural changes were determined via a series of assays. Moreover, levels of reactive oxygen species (ROS), expression of other factors such as VEGF, PEDF, IGF-1, HIF-1α, Bax, Bcl-2, eNOS, nNOS, and iNOS were detected. Astragalus root extract was found to protect blood-retinal barrier in the OIR model mice through repairing the structure and morphology of retina, inhibiting ROS production, retinal cell apoptosis, as well as improving retinal vascular angiogenesis. Astragalus root extract was also found to decrease VEGF and HIF-1α expression, but enhance PEDF and IGF-1 expression in the OIR model mice, thereby protecting retinas in ROP. This study highlights that Astragalus root extract is able to suppress retinal cell apoptosis and repair damaged retinal neovascularization in ROP, which provides basis for ROP therapy.

Evaluation of lamina cribrosa thickness in patients diagnosed with central retinal vein occlusion

PURPOSE

To evaluate the thickness of lamina cribrosa (LC) in both eyes of patients with unilateral central retinal vein occlusion (CRVO) and to compare with eyes of age-matched healthy control subjects.

METHODS

This prospective case-control study included a total of 38 patients with unilateral CRVO and 42 healthy control subjects. The LC thickness was measured at the center of the optic disc using an enhanced depth imaging with the spectral domain optical coherence tomography in both eyes of patients with unilateral CRVO and eyes of healthy control subjects. The LC thickness of CRVO patients was evaluated one month after dexamethasone intravitreal implant (Ozurdex) injection.

RESULTS

The mean LC thickness in affected eyes of patients with CRVO was significantly thinner than that of the healthy eyes (204.4 ± 8.8 and 228.0 ± 7.1 μm, p < 0.001, respectively). Also, the unaffected fellow eyes had significantly thinner LC compared with eyes of healthy subjects (205.3 ± 9.3 and 228.0 ± 7.1 μm, p < 0.001, respectively). There was no statistically significant difference in the thickness of LC between the affected and unaffected fellow eyes (p = 0.669).

CONCLUSIONS

The LC thickness in both eyes of CRVO patients was thinner than that of the healthy eyes. This finding suggests that thin LC may contribute to the development of CRVO as an ocular risk factor in addition to systemic factors.

Aqueous semaphorin 3A level correlates with retinal macular oedema and ganglion cell degeneration in patients with retinal vein occlusion

PURPOSE

To investigate the semophorin 3A (SEMA3A) level in aqueous humor of patients with retinal vein occlusion (RVO) and explore the correlation of SEMA3A with macular oedema and ganglion cell degeneration in RVO.

METHODS

This comparative study prospectively included 41 consecutive patients (41 eyes) with RVO who had intravitreal anti-VEGF injections from March 2014 to March 2015 for cystoid macular oedema (CME) or neovascular glaucoma (NVG). The patients were divided into three groups according to the fluorescein angiograghy (FFA): central retinal vein occlusion (CRVO) group (n = 15), branch retinal vein occlusion (BRVO) group (n = 15) and NVG group (secondary to CRVO, n = 11). The patients who had undergone cataract surgery (n = 16) during the same period served as controls. The SEMA3A concentration in aqueous humor collected before the initial anti-VEGF injection was determined by enzyme-linked immunosorbent assay (ELISA). Central retinal thickness (CRT), cube volume (CV) and ganglion cell-inner plexiform layer (GC-IPL) thickness was analysed by spectral-domain optical coherence tomography (SD-OCT).

RESULTS

Semaphorin 3A level in CRVO group (1.52 ± 1.23 ng/ml) and NVG group (1.67 ± 0.98 ng/ml) were significantly higher than the control group (0.66 ± 0.58 ng/ml; both p < 0.05). Moreover, SEMA3A level in CRVO group was higher than BRVO group (1.52 ± 1.23 ng/ml versus 0.53 ± 0.37 ng/ml; p < 0.05). SEMA3A level was positively correlated with CRT and CV in both BRVO group (CRTr = 0.6535, p = 0.0082; CVr = 0.5190, p = 0.0474) and CRVO group (CRTr = 0.6270, p = 0.0124; CVr = 0.6898, p = 0.0044). In RVO patients, the GC-IPL thickness of affected eyes were significantly reduced compared with the normal follow eyes (CRVOt = 4.55, p = 0.006; BRVOt = 4.54, p = 0.004). Meanwhile, negative correlation of SEMA3A level with GC-IPL thickness was found in both BRVO group (r = -0.5906, p = 0.0205) and CRVO group (r = -0.6100, p = 0.0157).

CONCLUSION

Semaphorin 3A level is increased in aqueous humor of RVO patients. Positive correlation of CRT as well as negative correlation of GC-IPL thickness with SEMA3A may suggest a pathological role of SEMA3A in macular oedema and ganglion cell degeneration during RVO.

Intravitreal Injection of Anti-vascular Endothelial Growth Factor Agents for Ocular Vascular Diseases: Clinical Practice Guideline

PURPOSE

To provide the clinical recommendations for the administration of intravitreal anti-vascular endothelial growth factor (VEGF) drugs especially bavacizumab for ocular vascular diseases including diabetic macular edema, neovascular age-related macular degeneration, myopic choroidal neovascularization, retinal vein occlusion and central serous chorioretinopathy.

METHODS

Twenty clinical questions were developed by the guideline technical committee. Relevant websites and databases were searched to find out the pertinent clinical practice guidelines to answer the questions. The technical committee provided possible answers (scenarios) according to the available evidences for each question. All scenarios along with their levels of evidence and the supported articles were sent to the experts for external review. If the experts did not agree on any of the scenarios for one particular clinical question, the technical committee reviewed all scenarios and their pertinent evidences and made the necessary decision. After that, the experts were asked to score them again. All confirmed scenarios were gathered as the final recommendations.

RESULTS

All the experts agreed on at least one of the scenarios. The technical committee extracted the agreed scenario for each clinical question as the final recommendation. Finally, 56 recommendations were developed for the procedure of intravitreal anti-VEGF injection and their applications in the management of ocular vascular diseases.

CONCLUSION

The implementation of this guideline can standardize the management of the common ocular vascular diseases by intravitreal injection of anti-VEGF agents. It can lead to better policy-making and evidence-based clinical decision by ophthalmologists and optimal evidence based eye care for patients.

Correlation between macular ganglion cell-inner plexiform layer thickness and visual acuity after resolution of the macular edema secondary to central retinal vein occlusion

AIM

To examine the thickness of the ganglion cell-inner plexiform layer (GCIPL) in eyes with resolved macular edema (ME) in non-ischemic central retinal vein occlusion (CRVO), applying spectral-domain optical coherence tomography (SD-OCT), and its relationship with visual acuity.

METHODS

The retrospective observational case-control study included 30 eyes of non-ischemic CRVO patients with resolved ME (ME eyes) after treatment, and 30 eyes of non-ischemic CRVO patients without ME (non-ME eyes). The macular GCIPL thickness, peripapillary retinal nerve fiber layer (pRNFL) thickness and central macular thickness (CMT) were measured on a SD-OCT scan. Linear regression analyses were performed to determine the correlation between the thickness of each and the visual acuity (VA).

RESULTS

No significant difference in average GCIPL thickness, mean pRNFL thickness and CMT were observed between ME group and non-ME group (P=0.296, 0.183, 0.846). But, minimum GCIPL thickness was reduced in ME eyes compared with non-ME eyes (P=0.022). Final VA significantly correlated with the minimum GCIPL thickness in ME eyes (r=-0.482, P=0.007), whereas no correlation was found with average GCIPL thickness, average pRNFL thickness and mean CMT.

CONCLUSION

Minimum GCIPL thickness is reduced in ME eyes compared with non-ME eyes, and correlated with the VA in non-ischemic CRVO. These results propose that inner retinal damage occurring in patients with ME secondary to non-ischemic CRVO may lead to permanent visual defect after treatment.

Quantitative analysis of neural tissues around the optic disc after panretinal photocoagulation in patients with diabetic retinopathy

In this retrospective cross-sectional study, we quantitatively analyzed the tomographic features in the neural tissues around the optic disc in patients with diabetic retinopathy with and without panretinal photocoagulation. We analyzed 206 eyes, comprising 33 normal eyes in subjects without diabetes (group I), 30 eyes without diabetic retinopathy (group II), 66 eyes with non-proliferative diabetic retinopathy (group III), 45 eyes with panretinal photocoagulation (group IV), and 32 eyes with normal tension glaucoma (group V). Sequential images acquired using swept-source optical coherence tomography in three-dimensional mode were used to measure peripapillary retinal nerve fiber layer thickness, neuro-retinal rim thickness, anterior lamina cribrosa depth, prelaminar thickness, and thickness of the lamina cribrosa. The peripapillary retinal nerve fiber layer thickness and lamina cribrosa thickness were significantly thinner in group IV than in group III (p = 0.019 and p < 0.001). However, there was no significant difference in rim thickness, anterior lamina cribrosa depth, or prelaminar thickness between groups III and IV (p = 0.307, p = 0.877, and p = 0.212). Multivariate analysis revealed that time since panretinal photocoagulation and thickness of the lamina cribrosa had a significant effect on peripapillary retinal nerve fiber layer thickness (p < 0.001 and p = 0.014). In group IV, there was a negative correlation between time elapsed since panretinal photocoagulation and peripapillary retinal nerve fiber layer thickness, rim thickness, and thickness of the lamina cribrosa (r = -0.765, r = -0.490, and r = -0.419), but no correlation with prelaminar thickness or anterior lamina cribrosa depth (r = 0.104 and r = -0.171). Panretinal photocoagulation may be related to thinning of the peripapillary retinal nerve fiber layer, rim thickness, and lamina cribrosa, but not prelaminar thickness or anterior lamina cribrosa depth. These features are different from the peripapillary features of eyes with typical normal tension glaucoma.

Changes in Peripapillary Nerve Fiber Layer Thickness after Adjuvant Stereotactic Radiotherapy in Patients with Neovascular Age-Related Macular Degeneration

PURPOSE

To evaluate the effect of stereotactic radiotherapy (SRT) in conjunction with intravitreal injections (IVI) of anti-vascular endothelial growth factor (anti-VEGF) drugs on peripapillary retinal nerve fiber layer (pRNFL) thickness in patients with neovascular age-related macular degeneration (nAMD).

METHODS

This was a retrospective, observational case series of patients with nAMD, who underwent SRT and subsequently had at least 12 months of complete follow-up. After SRT and one mandatory IVI, patients were examined monthly and received further treatment on a pro re nata basis. Examination included spectral-domain optical coherence tomography of the optic disc to measure pRNFL thickness. Patients' data were retrieved from medical records including demographics, disease duration, best-corrected visual acuity, previous number of intravitreal injections, and the type of drug applied.

RESULTS

A total of 35 eyes of 35 patients (76.23 ± 7.05 years) were included. The mean duration of nAMD at time of irradiation was 34.57 ± 16.96 months. During that time, patients received a mean total number of 15.83 ± 6.29 intravitreal injections, 6.86 ± 1.57 within the last 12 months before SRT. After SRT, on average 3.46 ± 2.09 injections were administered over 12 months, resulting in a mean total number of 19.29 ± 6.92 injections at final follow-up. The mean global pRNFL thickness was 97.23 ± 12.55 µm at time of irradiation, 95.54 ± 11.07 µm at 6 month (P = 0.299), and 95.29 ± 12.07 µm at 12 month (P = 0.373) follow-up.

CONCLUSION

SRT in conjunction with anti-VEGF injections did not lead to any significant change in pRNFL thickness over 12 months in patients with nAMD. However, long-term results are not yet available. Therefore, prospective studies with longer follow-up are needed to corroborate these findings.

COMPARISON OF THE LAMINA CRIBROSA THICKNESS OF PATIENTS WITH UNILATERAL BRANCH RETINAL VEIN OCCLUSION AND HEALTHY SUBJECTS

PURPOSE

To compare the lamina cribrosa (LC) thickness of healthy subjects and patients with unilateral branch retinal vein occlusion (BRVO), and to determine possible correlations between the LC thickness and the BRVO subtypes.

METHODS

This prospective, cross-sectional study included a total of 46 patients with naive, untreated, unilateral BRVO and 31 healthy control subjects. The occlusion site was divided into two BRVO types: arteriovenous crossing BRVO (AV-BRVO) and optic nerve BRVO (ON-BRVO). The optic nerve head was scanned using enhanced-depth imaging with the Spectralis optical coherence tomography system.

RESULTS

The mean LC thickness of both eyes in patients with BRVO was thinner than that of eyes (274.0 μm) of the healthy subjects (both, P < 0.001). Although the LC thickness of the BRVO-affected eyes was slightly thinner than that of the fellow eyes (237.0 μm vs. 241.4 μm, respectively), there was no statistically significant difference. In addition, there were no significant differences in the LC thicknesses of both eyes according to the site of occlusion.

CONCLUSION

A thinner LC was observed in both eyes of unilateral BRVO patients compared with those of healthy subjects. This finding suggests that thin LC may contribute to the pathogenesis of BRVO as a local mechanical factor in addition to systemic factors.

The acute and chronic effects of intravitreal anti-vascular endothelial growth factor injections on intraocular pressure: A review

The acute and chronic effects of repeated intravitreal antivascular endothelial growth factor (VEGF) injections on intraocular pressure have not been fully characterized, and the development of sustained ocular hypertension could adversely affect patients who are at risk of glaucomatous optic neuropathy. As expected, volume-driven, acute ocular hypertension immediately follows intravitreal injection, but this pressure elevation is generally transient and well tolerated. Several medications have been investigated to limit acute ocular hypertension following anti-VEGF therapy, but the benefits of pretreatment are not conclusive. Chronic, sustained ocular hypertension, distinct from the short-term acute ocular hypertension after each injection, has also been associated with repeated intravitreal anti-VEGF injections. Risk factors for chronic ocular hypertension include the total number of injections, a greater frequency of injection, and preexisting glaucoma. Proposed mechanisms for chronic ocular hypertension include microparticle obstruction, toxic or inflammatory effects on trabecular meshwork, as well as alterations in outflow facility by anti-VEGF agents. Although limiting anti-VEGF therapy could minimize the risk of both acute and chronic ocular hypertension, foregoing anti-VEGF therapy risks progression of various macular diseases with resulting permanent central vision loss. While definitive evidence of damage to the retinal nerve fiber layer is lacking, patients receiving repeated injections should be monitored for ocular hypertension and patients in whom sustained ocular hypertension subsequently developed should be periodically monitored for glaucomatous changes with optic nerve optical coherence tomography and static visual fields.

Inner retinal layer change in glaucoma patients receiving anti-VEGF for neovascular age related macular degeneration

PURPOSE

The purpose was to evaluate the effects of long-term anti-VEGF treatment on the retinal nerve fiber layer (RNFL) and retinal ganglion cell layer (RGCL) thickness for patients with neovascular AMD and glaucoma.

METHODS

Medical records of respective patients who had received more than 15 anti-VEGF injections were reviewed. Initial and latest SD-OCT macular scans were segmented and changes of the RNFL and RGCL thickness at the four outer ETDRS quadrants were evaluated. Secondary outcome measures included changes of visual field parameters seen in automated perimetry.

RESULTS

Sixteen patients were included (mean age 78 ± 6 years). The mean total number of anti-VEGF injections was 39 ± 16. The mean treatment duration was 6.1 ± 2.1 years. The mean IOP decreased from 18 ± 5 mmHg at baseline to 15 ± 5 mmHg at the last visit (p = 0.026). The mean RNFL thickness volume of the outer ETDRS quadrants (0.98 ± 0.18 mm³ to 0.97 ± 0.18 mm³ p = 0.61) and its average thickness (37.9 ± 7.3 μm to 37.2 ± 7.4 μm, p = 0.6) did not significantly change. However, the average RGCL thickness decreased significantly from 0.86 ± 0.12 mm³ to 0.79 ± 0.11 mm³ (p = 0.01), and from 27.7 ± 4.2 to 25.9 ± 3.7 μm (p = 0.01). Number of injections correlated with the RGCL change (r2 = 0.36, p = 0.01). The mean sensitivity, mean defect and absolute scotomata did not significantly change with p-values of 0.28, 0.21 and 0.07, respectively.

CONCLUSION

Patients under long term treatment with anti-VEGF and concurrent glaucoma show significant decrease in macular RGLC volume. However, this decrease is comparable to reported RGCL decrease in patients under anti-VEGF treatment without underlying glaucoma and suggests that glaucoma patients may not be at a higher risk for losing macular RNFL and RGCL, at least if adequate control of intraocular pressure is maintained.

Co-Evaluation of Peripapillary RNFL Thickness and Retinal Thickness in Patients with Diabetic Macular Edema: RNFL Misinterpretation and Its Adjustment

We investigated the relationship between the peripapillary retinal nerve fiber layer and peripapillary retinal thickness in patients with diabetic macular edema. Fifty eyes (group I) with non-proliferative diabetic retinopathy and diabetic macular edema receiving intravitreal anti-VEGF injection, and 90 eyes (group II) without diabetic macular edema were included in this case-control study. The peripapillary retinal nerve fiber layer thickness, peripapillary retinal thickness, and a new retinal nerve fiber layer index using a modeled relationship between the two parameters were evaluated with spectral-domain optical coherence tomography, at baseline and at the 6-month follow-up. In group I, the peripapillary retinal nerve fiber layer thickness decreased from 126.4 μm at baseline to 117.6 μm at 6 months (p < 0.001), while the peripapillary retinal thickness decreased from 376.0 μm at baseline to 359.6 μm at 6 months (p < 0.001) after intravitreal anti-VEGF injection. In group II, however, both the parameters remained stable at the 6-month follow-up (100.7 to 102.1 μm and 311.1 to 316.2 μm, respectively, and all p > 0.01). Analysis with the new index to adjust for retinal edema showed no significant change from baseline to 6 months in both groups (p = 0.593 and p = 0.101, respectively). The peripapillary retinal nerve fiber layer thickness is strongly affected by the peripapillary retinal thickness. Therefore, the measured changes in peripapillary retinal nerve fiber layer thickness may not represent the real gain or loss of the retinal nerve fiber layer. Therefore, the new retinal nerve fiber layer index, which corrects for the component of macula edema, could be a better means of assessing the changes of peripapillary retinal nerve fiber layer thickness in patients with diabetic macular edema.

Effects of Panretinal Laser Photocoagulation on the Corneal Nerve Plexus and Retinal Nerve Fiber Layer in Retinal Vein Occlusion

Purpose

To determine the effects of panretinal photocoagulation (PRP) on corneal sub-basal nerve plexus (SBNP) and peripapillary retinal nerve fiber layer (RNFL) thickness in patients with unilateral central retinal vein occlusion (CRVO) who had previously undergone PRP treatment.

Methods

Sixty-four eyes of 32 patients (19 male, 13 female) with unilateral ischemic type CRVO who had undergone PRP treatment at least 6 months previously were included in this cross-sectional study. The laser scanning in vivo corneal confocal microscope was used to determine corneal SBNP parameters. The peripapillary RNFL thickness was assessed with spectral-domain optical coherence tomography. Data obtained from the PRP-treated eyes were compared with those of the fellow unaffected eyes.

Results

The mean age of patients was 63.5 ± 10.7 years (range 45-85 years). The mean nerve fiber density (NFD), nerve branch density, and nerve fiber length (NFL) were significantly lower in PRP-treated eyes compared with fellow eyes (p<0.001 for all). Average peripapillary RNFL thickness was significantly lower in PRP-treated eyes than in fellow eyes (p = 0.007). The NFD and NFL showed a modest but significant positive correlation with average peripapillary RNFL thickness (r = 0.310, p = 0.013 and r = 0.272, p = 0.030, respectively).

Conclusions

Significant reductions in corneal SBNP parameters and average peripapillary RNFL thickness were observed in the eyes of patients receiving PRP for the treatment of ischemic CRVO.

Assessment of Corneal Sensation, Innervation and Retinal Nerve Fiber Layer in Patients Treated with Multiple Intravitreal Ranibizumab Injections

PURPOSE

To evaluate the effects of repeated intravitreal ranibizumab injections on corneal sensitivity, corneal sub-basal nerve plexus (SBNP) and peripapillary retinal nerve fiber layer (RNFL) thickness in patients with neovascular age-related macular degeneration (AMD).

METHODS

Sixty-six eyes of 33 patients who had received unilateral repeated intravitreal ranibizumab injections (0.5 mg/0.05 ml) for the treatment of AMD and 25 eyes of 25 healthy subjects were included in the study. Central corneal sensation was measured using the contact Cochet-Bonnet esthesiometer. The laser scanning in vivo corneal confocal microscope was used to determine corneal SBNP parameters. The peripapillary RNFL thickness was assessed with spectral-domain optical coherence tomography. Data obtained from the ranibizumab-injected eyes were compared with those of the fellow non-treated eyes and the eyes of the healthy control subjects.

RESULTS

The mean number of ranibizumab injections per eye was 8.9±5.0 (range 3-20). There were no statistically significant differences in the central corneal sensitivity threshold and corneal SBNP parameters between the ranibizumab-injected eyes and the fellow untreated eyes or between those with neovascular AMD and the healthy control group (P>0.05 for all). The average peripapillary RNFL thickness of the treated eyes did not differ significantly to the fellow eyes (P = 0.237), and the eyes of healthy control subjects (P = 0.918). There were no significant correlations between the number of ranibizumab injections and any of the study parameters.

CONCLUSIONS

Multiple intravitreal injections of ranibizumab seem to have no harmful effects on corneal sensitivity, innervation and peripapillary RNFL thickness in patients with AMD.

Changes in Retinal Nerve Fiber Layer Thickness after Multiple Injections of Novel VEGF Decoy Receptor Conbercept for Various Retinal Diseases

Conbercept is a recombinant fusion protein with high affinity for all vascular endothelial growth factor isoforms and placental growth factor. The repeated intravitreal injection of conbercept may cause intraocular pressure (IOP) fluctuations and long-term suppression of neurotrophic cytokines, which could lead to retinal nerve fiber layer (RNFL) damage. This retrospective fellow-eye controlled study included 98 eyes of 49 patients. The changes in IOP and RNFL thickness as well as the correlation between RNFL changes and associated factors were evaluated. The IOP value between the baseline and the last follow-up visit in the injection group and the IOP value of the last follow-up visit between the injection and non-injection groups were not significantly different (p = 0.452 and 0.476, respectively). The global average thickness of the RNFL (μm) in the injection group decreased from 108.9 to 106.1; however, the change was not statistically significant (p = 0.118). No significant difference in the average RNFL thickness was observed at the last follow-up visit between the injection and non-injection groups (p = 0.821). The type of disease was the only factor associated with RNFL thickness changes. In conclusion, repeated intravitreal injections with 0.05 mL conbercept revealed an excellent safety profile for RNFL thickness, although short-term IOP changes were observed.

Retinal Ganglion Cell Layer Change in Patients Treated With Anti-Vascular Endothelial Growth Factor for Neovascular Age-related Macular Degeneration

PURPOSE

To evaluate macular retinal ganglion cell thickness in patients with neovascular age-related macular degeneration (AMD) and intravitreal anti-vascular endothelial growth factor (VEGF) therapy.

DESIGN

Retrospective case series with fellow-eye comparison.

METHODS

Patients with continuous unilateral anti-VEGF treatment for subfoveal and juxtafoveal neovascular AMD and a minimum follow-up of 24 months were included. The retinal nerve fiber (RNFL) and retinal ganglion cell layer (RGCL) in the macula were segmented using an ETDRS grid. RNFL and RGCL thickness of the outer ring of the ETDRS grid were quantified at baseline and after repeated anti-VEGF injections, and compared to the patients' untreated fellow eye. Furthermore, best-corrected visual acuity (BCVA), age, and retinal pigment epithelium (RPE) atrophy were recorded and correlated with RNFL and RGCL.

RESULTS

Sixty eight eyes of 34 patients (23 female and 11 male; mean age 76.7 (SD ± 8.2) with a mean number of 31.5 (SD ± 9.8) anti-VEGF injections and a mean follow-up period of 45.3 months (SD ± 10.5) were included. Whereas the RGCL thickness decreased significantly compared to the noninjected fellow eye (P = .01), the decrease of the RNFL was not significant. Visual acuity gain was significantly correlated with RGCL thickness (r = 0.52, P < .05) at follow-up and negatively correlated (r = -0.41, P < .05) with age. Presence of RPE atrophy correlated negatively with the RGCL thickness at follow-up (r = -0.37, P = .03).

CONCLUSION

During the course of long-term anti-VEGF therapy there is a significant decrease of the RGCL in patients with neovascular AMD compared to the fellow (untreated) eye.

Changes in intraocular pressure in study and fellow eyes in the IVAN trial

PURPOSE

To describe changes in intraocular pressure (IOP) in the 'alternative treatments to Inhibit VEGF in Age-related choroidal Neovascularisation (IVAN)' trial (registered as ISRCTN92166560).

DESIGN

Randomised controlled clinical trial with factorial design.

PARTICIPANTS

Patients (n=610) with treatment naïve neovascular age-related macular degeneration were enrolled and randomly assigned to receive either ranibizumab or bevacizumab and to two regimens, namely monthly (continuous) or as needed (discontinuous) treatment.

METHODS

At monthly visits, IOP was measured preinjection in both eyes, and postinjection in the study eye.

OUTCOME MEASURES

The effects of 10 prespecified covariates on preinjection IOP, change in IOP (postinjection minus preinjection) and the difference in preinjection IOP between the two eyes were examined.

RESULTS

For every month in trial, there was a statistically significant rise in both the preinjection IOP and the change in IOP postinjection during the time in the trial (estimate 0.02 mm Hg, 95% CI 0.01 to 0.03, p<0.001 and 0.03 mm Hg, 95% CI 0.01 to 0.04, p=0.002, respectively). There was also a small but significant increase during the time in trial in the difference in IOP between the two eyes (estimate 0.01 mm Hg, 95% CI 0.005 to 0.02, p<0.001). There were no differences between bevacizumab and ranibizumab for any of the three outcomes (p=0.93, p=0.22 and p=0.87, respectively).

CONCLUSIONS

Anti-vascular endothelial growth factor agents induce increases in IOP of small and uncertain clinical significance.

TRIAL REGISTRATION NUMBER

ISRCTN92166560.

Macular ganglion cell complex and retinal nerve fiber layer comparison in different stages of age-related macular degeneration

PURPOSE

To employ optical coherence tomography (OCT) to analyze the morphologic changes in the inner retina in different categories of age-related macular degeneration (AMD).

DESIGN

Observational cross-sectional study.

METHODS

Single-center study. Inclusion criteria were age over 50, diagnosis of Age-Related Eye Disease Study (AREDS) category 2 and 3, naïve neovascular AMD, and atrophic AMD. Healthy patients of similar age acted as a control group. Primary outcome measures were the changes in ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL). Secondary outcomes included modifications of rim area and cup-to-disc ratio.

RESULTS

One hundred and thirty eyes of 130 patients were recruited: 26 eyes for AREDS category 2, 26 for AREDS category 3, 26 for neovascular AMD, 26 with atrophic AMD, and 26 controls. Mean peripapillary RNFL thickness was significantly lower in neovascular AMD, compared to controls (P = .004); peripapillary RNFL did not significantly vary among AREDS category 2 and 3 and atrophic AMD groups, compared to controls. Mean GCC thickness was higher in the control group, becoming progressively thinner up to neovascular and atrophic AMD groups (P < .0001). Rim area was significantly thinner in the neovascular AMD group compared with controls (P = .047); cup-to-disc ratio was higher in the neovascular AMD group compared with the control group (P = .047).

CONCLUSIONS

This study demonstrates that eyes with neovascular AMD display reduced RNFL and GCC thickness. RNFL is partially spared in atrophic advanced AMD. The identification of alteration in RNFL and GCC thickness may reveal useful for future therapeutic implications.

Pathogenesis, prevention, diagnosis and management of retinal vein occlusion

Retinal vein occlusion (RVO) is the second vascular retinal cause of visual loss and defined by the occlusion of a retinal vein. It is divided into branch retinal vein occlusion or central retinal vein occlusion, depending on the location of occlusion. RVO has severe medical, financial and social implications on the patients. The diagnosis of the disease is easier nowadays with the use of spectral domain optical coherence tomography and fluorescein angiography. The treatment options for RVO have changed dramatically over the past few years with the introduction of the intravitreal injections of dexamethasone (Ozurdex), bevacizumab (Avastin), ranibizumab (Lucentis) and aflibercept (EYLEA), along with the panretinal laser photocoagulation, abandoning former treatment modalities and surgical solution. This manuscript is a review of current literature about RVO with emphasize on the pathophysiology, risk factors and prevention, diagnosis and sub-group categorization and treatments including medical and surgical. Since no official guidelines are available for the treatment of RVO patients, and considering the latest developments in the treatment options, and the variety of follow-up and treatment modalities, this manuscript aims to provide tools and knowledge to guide the physician in treating RVO patients, based on the latest publications from the literature and on several of the patients characteristics.