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

The progress of assessment methods and treatments of neovascular glaucoma secondary to central retinal vein occlusion

Neovascular glaucoma is a condition that results from central retinal vein occlusion and often leads to blindness. Accurate evaluation and appropriate treatment are crucial for patients. However, there is currently no uniform and clear standard to differentiate between ischemic and non-ischemic central retinal vein occlusion. Also, the assessment of neovascular glaucoma progression is uncertain. Meanwhile, although pan-retinal photocoagulation is a standard treatment to prevent the onset of neovascular glaucoma, its actual efficacy and the timing of intervention remain highly controversial. It is still challenging to balance the risks of side effects in the visual field against the uncertain effectiveness of the treatment. This paper delves into the pathogenesis of neovascular glaucoma to understand the development of therapeutic approaches. By taking into account various assessment criteria of central retinal vein occlusion and neovascular glaucoma over the years, combining functional tests and morphological tests provides the most accurate and rigorous solution. The age of patients, the extent, location, and duration of retinal ischemia are the primary factors that affect the severity and extent of ischemic central retinal vein occlusion and induce serious complications. From the perspective of prevention and treatment, the ischemic index is closely related to the development of neovascularization. The paper provides essential insights into the mechanism, efficacy, complications, and optimal timing of pan-retinal photocoagulation. Comparing the treatment effects of pan-retinal photocoagulation and intravitreal anti-VEGF injections, we suggest a combination of both treatments to explore effective treatment with fewer side effects in the long term. This article details the debate on the above issues and explores ideas for the clinical diagnosis and preventive treatment of neovascular glaucoma that results from ischemic central retinal vein occlusion.

Clinical Features Associated with Acute Elevated Intraocular Pressure After Intravitreal Anti-VEGF Injections

Purpose

To study the effects of intravitreal injection (IVI) of anti-VEGF (vascular endothelial growth factor) agents on intraocular pressure (IOP) and find associations with acute pressure spikes.

Methods

This was a three-month, prospective study of patients receiving outpatient IVI of anti-VEGF agents for diabetic retinopathy (DR), age-related macular degeneration (AMD), and retinal vein occlusion (RVO) at the Acuity Eye Group Medical Centers. IOP was measured pre- and post-injection at 10-minute intervals up to 50 minutes after injection with a handheld tonometer. Patients with an IOP greater than 35 mmHg at 30 minutes received an anterior chamber paracentesis (ACP), while patients below 35 mmHg were monitored without intervention.

Results

A total of 617 patients (51% female, 49% male) received IVI for DR (n = 199), AMD (n = 355), and RVO (n = 63). ACP was performed in 17 patients. Average pre-injection IOP was 16 ± 4 compared to 24 ± 7 mmHg for the non-ACP vs ACP group, respectively (mean ± standard deviation), p < 0.0001. IOP returned to baseline in 98% of patients at 50 minutes. A diagnosis of glaucoma and glaucoma suspect was more prevalent in the ACP group compared to the non-ACP group, 82.3% vs 14.2% and 17.6% vs 9.0%, respectively, p < 0.0001 and p > 0.05. Patients with a pre-injection IOP >25 mmHg and a history of glaucoma had a 58.3% rate of ACP. A 31-gauge needle had a higher mean increase in IOP from baseline compared to 30-gauge needle, p < 0.0001.

Conclusion

IOP spikes are most significant in the first 10 minutes after IVI but typically resolve within the first hour. However, utilizing a smaller 31-gauge IVI in patients with a glaucoma history and pre-injection IOP >25 mmHg may be associated with significant IOP spikes lasting longer than 30 minutes.

Risk of Intraocular Pressure Increase With Intravitreal Injections of Vascular Endothelial Growth Factor Inhibitors: A Cohort Study

PURPOSE

Intraocular pressure increase (IOPi) after intravitreal injections of vascular endothelial growth factor inhibitors (VEGFis) might be different among different VEGFis (bevacizumab, aflibercept, ranibizumab). The purpose of this study was to evaluate the risk of IOPi among new users of bevacizumab, ranibizumab, and aflibercept in nondiabetic patients in Tuscany, Italy.

DESIGN

Retrospective cohort study.

METHODS

Tuscan regional administrative database was used to identify subjects with a first VEGFi intravitreal injection between 2011 and 2020, followed to first incidence of IOPi. Diabetic subjects, those with pre-existing IOPi, or previous use of dexamethasone implants were excluded. Multivariable Cox regression analyses (intention-to-treat and as treated) were conducted to evaluate risk of IOPi among aflibercept, bevacizumab, and ranibizumab, adjusting for potential confounding variables. IOPi was defined as the first record of International Classification of Diseases, Ninth Revision (ICD-9-CM) code 365 or use of 2 glaucoma drugs dispensations within 180 days of each other.

RESULTS

We identified 6585 new users of VEGFis: 1749 aflibercept, 1112 bevacizumab, and 3724 ranibizumab. Women made up 60% of the cohort, with a mean age of 73.6 years. In the intention-to-treat analysis, the adjusted hazard ratio (HR) for incident IOPi, compared with aflibercept, was higher for bevacizumab (HR = 2.20, 95% CI = 1.64-2.95) and ranibizumab users (HR = 1.88, 95% CI = 1.46-2.42), respectively. The HRs remained robust after exclusion of patients with proxy of retinal vascular occlusion. As treated analysis confirmed such results (bevacizumab: HR = 3.76, 95% CI = 2.30-6.17; ranibizumab: HR = 2.49, 95% CI = 1.62-3.82).

CONCLUSIONS

This study found an increased risk of IOPi among nondiabetic patients with ranibizumab and bevacizumab compared with aflibercept. Future studies are needed to validate these findings.

Incidence of ocular hypertension after anti-VEGF injections: examining the effect of drug filtration and silicone-free syringes

OBJECTIVE

To examine the difference in incidence of ocular hypertension (OHT) following the introduction of filtered anti-vascular endothelial growth factor (anti-VEGF) medication in silicone-free syringes.

DESIGN

Retrospective cohort study.

METHODS

A retrospective review of consecutive treatment-naive patients receiving intravitreal anti-VEGF injections in a group practice was performed. Data from the cohort receiving nonfiltered anti-VEGF in insulin syringes (IS group) was collected from June 2015. Data from the cohort receiving filtered anti-VEGF in silicone-free syringes (SFS group) was collected from June 2019. Follow up data were collected at 1 year. Exclusion criteria included prior anti-VEGF treatment, known glaucoma or diagnosis of glaucoma suspect before anti-VEGF treatment, neovascular glaucoma, steroid use, or vitrectomy during follow-up. Primary outcome was the cumulative incidence of intraocular pressure (IOP) > 21 mmHg and IOP ≥ 30 mm Hg at any follow-up visit. The use of IOP lowering therapy was also recorded.

RESULTS

The mean age (71 ± 13 years), mean number of injections (9.6 ± 2.7), and median follow-up time (392 ± 57 days) were similar between groups. The incidence of IOP ≥ 21 mm Hg was 34% (34/100) in the IS group and 15% (15/100) in the SFS group (p = 0.025). The incidence of IOP ≥ 30 mm Hg was 8% (8/100) in the IS group and 0% (0/100) in the SFS group (p =0.004). The incidence of IOP-lowering therapy was 13% in the IS group and 0% in the SFS group (p =0.0002).

CONCLUSION

The incidence of OHT and treatment with IOP-lowering therapy significantly decreased after the introduction of filtered anti-VEGF medication and silicone-free syringes.

Intraocular pressure decreases in eyes with glaucoma-related diagnoses after conversion to aflibercept for treatment-resistant age-related macular degeneration

OBJECTIVE

To understand intraocular pressure (IOP) response after switching from intravitreal bevacizumab (IVB) and/or ranibizumab (IVR) to intravitreal aflibercept (IVA) for treatment-resistant neovascular age-related macular degeneration (nAMD) in patients with and without coexisting glaucoma-related diagnoses.

METHODS

Retrospective, cross-sectional comparative case series of 62 eyes of 58 patients treated with intravitreal injection for nAMD from March 2010 to April 2018. Patients with glaucoma-related diagnoses, defined here as open-angle glaucoma or suspicion of open-angle glaucoma, ocular hypertension, and/or narrow-angle glaucoma, were compared to those without glaucoma. IOP data were collected at baseline, at the three visits where patients received loading doses of IVB/IVR, and at all of the visits following the switch to IVA through the end of follow-up.

RESULTS

19 eyes with pre-existing glaucoma-related diagnoses were compared to 43 eyes without such diagnoses. Baseline IOP was similar for glaucoma and non-glaucoma patients. The loading doses of IVB/IVR did not impact IOP; however, a small, sustained rise in IOP was noted among patients with glaucoma-related diagnoses by the final IVB/IVR injections before the switch to IVA (∆IOP 1.61 ± 0.52 mmHg, P < 0.002). After conversion to IVA, pre-injection IOP declined in eyes both with (-1.59 ± 0.54 mmHg, P < 0.001) and without (-0.99 ± 0.28 mmHg, P < 0.001) glaucoma-related diagnoses.

CONCLUSIONS

IOP in patients with glaucoma-related diagnoses appears to be more sensitive to intravitreal injections than it is in patients without glaucoma-related diagnoses. It rises with IVB/IVR and declines after the switch to IVA. Switching patients with nAMD to IVA may present an opportunity to lower IOP in patients with glaucoma.

Mid-Term Impact of Anti-Vascular Endothelial Growth Factor Agents on Intraocular Pressure

The effect of intraocular injections of anti-vascular endothelial growth factor (VEGF) on intraocular pressure (IOP) has not been clearly stated. We extracted data from the electronic health records at Dijon University Hospital of 750 patients who were unilaterally injected with anti-VEGF agents between March 2012 and March 2020. These were treatment-naïve patients who had received at least three injections of the same treatment (aflibercept, bevacizumab, or ranibizumab) in one eye only, and had IOP measurements before and after the injections. Fellow untreated eyes were used as comparators. A clinically significant IOP rise was determined as an IOP above 21 mmHg and an increase of at least 6 mmHg compared to baseline, or the need for IOP-lowering agents. We found an overall slight increase in IOP between treated and untreated eyes at 6 months (+0.67 ± 3.33 mmHg, 95% confidence interval 0.33–1.02, p < 0.001). Ranibizumab had a higher final IOP at 1 and 3 months. Age, sex, and the number of injections were not associated with IOP variation. Ranibizumab was associated with a higher rate of increase in clinically significant IOP at 6 months (p = 0.03). Our study confirms that anti-VEGF injections constitute a relatively safe treatment regarding their impact on IOP.

[Ocular hypertension after intravitreal injections]

Intravitreal injections (IVI) of anti-vascular endothelial growth factor (anti-VEGF) for the treatment of age-related macular degeneration with choroidal neovascularization have become much more popular nowadays. Anti-VEGF therapy is generally well-tolerated; however, one of its possible side effects is ocular hypertension - elevation of intraocular pressure (IOP) above the accepted norm, but without structural and functional changes in the retina and optic nerve common for glaucoma. The average duration of IOP elevation is 30 to 60 minutes, but it can increase when the patient has primary open-angle glaucoma (POAG). There is currently no uniform understanding of the pathogenesis of elevated IOP after IVI, as well as the effect of IOP fluctuations on the functional prognosis and the condition of the ocular tunics. This review considers the main causes and mechanisms of IOP elevation after IVI, analyzes recent publications on the consequences of ocular hypertension for the neurosensory part of the retina and the optic nerve, and examines the conditions for transition of IOP fluctuations into clinically significant ocular hypertension or POAG.

Intraocular Pressure Elevation Following Intravitreal Anti-VEGF Injections: Short- and Long-term Considerations

Published studies agree that transient intraocular pressure (IOP) spikes are common after intravitreal injections of anti-vascular endothelial growth factor agents. Currently, there is no standard of care guiding if and when to prevent these IOP spikes. Furthermore, there are challenges in determining the impact of postinjection IOP elevation on the health of the retinal ganglion cells, particularly given the often-existing comorbidities of retinal and glaucoma pathology. This review highlights the current literature regarding both acute and chronic postinjection IOP elevations and discusses management of postinjection IOP elevation, especially in patients at high risk for glaucomatous damage.

Underdiagnosis of glaucoma in patients with exudative age-related macular degeneration

OBJECTIVE

To compare the rate of glaucoma-related diagnoses in patients with exudative or non-exudative age-related macular degeneration (AMD).

METHODS

Patients above the age of 55 with a diagnosis of AMD were identified from billing records from 2015 to 2018. Out of the 3991 patients with AMD, two cohorts with 990 patients in each were formed by randomly age-matching patients with exudative AMD with those with non-exudative AMD; patients within each group were further classified by subtype and severity of glaucoma. Charts of AMD patients without glaucoma-related diagnoses were reviewed to determine potential underdiagnosis. We applied a set of broad clinical criteria that comprised an intraocular pressure ≥22 mmHg, a cup-to-disc ratio (CDR) ≥ 0.6, and/or CDR difference between eyes of ≥0.2.

RESULTS

The rate of diagnosed, open-angle glaucoma was significantly lower in patients with exudative AMD (6.06%) compared to patients with non-exudative AMD (8.99%, P = 0.04). Similarly, the rate of suspected glaucoma was significantly lower in the first group compared to the second (12.12% versus 18.48%, respectively, P < 0.001). A greater number of patients with exudative AMD (13.94%, n = 138) met clinical risk criteria compared with those having non-exudative AMD (6.97%, n = 69, P < 0.001). When these at-risk patients were added to their respective groups, the rate of glaucoma, or its suspicion, became similar (χ² = 1.24, P = 0.539).

CONCLUSIONS

A significantly lower rate of diagnosed glaucoma, or its suspicion, was identified in patients with exudative compared to non-exudative AMD. This apparent underdiagnosis was resolved by the retrospective application of clinical criteria that may represent a risk of glaucoma.

Low-dose Bevacizumab Decreases Ocular Hypotensive Effect of Angiotensin II in Sprague Dawley Rats

PURPOSE

Although the effectiveness of anti-VEGF agents in ophthalmology has been thoroughly documented, we do not fully comprehend the epidemiology and mechanistic background of their side effects, including intraocular and systemic hypertension. Here, we investigate the interference of a low-dose bevacizumab with key neuronal and humoral mechanisms maintaining blood and intraocular pressure homeostasis.

MATERIALS AND METHODS

Intraocular pressure (IOP), blood pressure (BP), and heart rate (HR) were measured in SPRD rats pretreated with bevacizumab or 0.9% NaCl at baseline and after infusion of angiotensin II, a humoral mediator involved in BP and IOP regulation. Superior cervical gangliectomy was performed to assess the effect of sympathetic nervous system on the analyzed parameters. Additionally, we studied the expression of a subset of genes related to renin-angiotensin system in the anterior segment of the eye.

RESULTS

At baseline, there was no significant difference in IOP, BP, and HR between rats pretreated with 0.9% NaCl and bevacizumab. Infusion of angiotensin II lowered IOP in rats pretreated with 0.9% NaCl, but not in rats pretreated with bevacizumab (30 min: ∆4.22 ± 1.2 vs. baseline, p > .05; ∆0.83 ± 0.66 vs. baseline, p < .05) This effect was paralleled by an increased expression of angiotensin II type 1b and type 2 receptors in the anterior segment of the eye (AT1b: 1 ± 0.65 vs 7.35 ± 2.84, p < .05; AT2: 1 ± 0.05 vs. 12.8 ± 0.1, p < .05). Angiotensin II infusion increased BP in both groups (10 min: bevacizumab ∆44.6 ± 3.2, p < .05; 0.9%NaCl ∆37.1 ± 5.1, p < .05), whereas did not have any effect on HR. Sympathetic ocular denervation did not affect any of the analyzed parameters.

CONCLUSIONS

We found that low-dose bevacizumab interferes with IOP-lowering properties of angiotensin II. This effect might be related to increased expression of angiotensin II receptors in the anterior segment of the eye.

Treatment regimens for administration of anti-vascular endothelial growth factor agents for neovascular age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is one of the leading causes of permanent blindness worldwide. The current mainstay of treatment for neovascular AMD (nAMD) is intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents: aflibercept, ranibizumab, and off-label bevacizumab. Injections can be given monthly, every two or three months ('extended-fixed'), or as needed (pro re nata (PRN)). A variant of PRN is 'treat-and-extend' whereby injections are resumed if recurrence is detected and then delivered with increasing intervals. Currently, injection frequency varies among practitioners, which underscores the need to characterize an optimized approach to nAMD management.

OBJECTIVES

To investigate the effects of monthly versus non-monthly intravitreous injection of an anti-VEGF agent in people with newly diagnosed nAMD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, and three trials registers from 2004 to October 2019; checked references; handsearched conference abstracts; and contacted pharmaceutical companies to identify additional studies.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared different treatment regimens for anti-VEGF agents in people with newly diagnosed nAMD. We considered standard doses only (ranibizumab 0.5 mg, bevacizumab 1.25 mg, aflibercept 2.0 mg, or a combination of these).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for trial selection, data extraction, and analysis.

MAIN RESULTS

We included 15 RCTs. The total number of participants was 7732, ranging from 37 to 2457 in each trial. The trials were conducted worldwide. Of these, six trials exclusively took place in the US, and three included centers from more than one country. Eight trials were at high risk of bias for at least one domain and all trials had at least one domain at unclear risk of bias. Seven trials (3525 participants) compared a PRN regimen with a monthly injection regimen, of which five trials delivered four to eight injections using standard PRN and three delivered nine or 10 injections using a treat-and-extend regimen in the first year. The overall mean change in best-corrected visual acuity (BCVA) at one year was +8.8 letters in the monthly injection group. Compared to the monthly injection, there was moderate-certainty evidence that the mean difference (MD) in BCVA change at one year for the standard PRN subgroup was -1.7 letters (95% confidence interval (CI) -2.8 to -0.6; 4 trials, 2299 participants), favoring monthly injections. There was low-certainty evidence of a similar BCVA change with the treat-and-extend subgroup (0.5 letters, 95% CI -3.1 to 4.2; 3 trials, 1226 participants). Compared to monthly injection, there was low-certainty evidence that fewer participants gained 15 or more lines of vision with standard PRN treatment at one year (risk ratio (RR) 0.87, 95% CI 0.76 to 0.99; 4 trials, 2299 participants) and low-certainty evidence of a similar gain with treat-and-extend versus monthly regimens (RR 1.11, 95% CI 0.91 to 1.36; 3 trials, 1169 participants). The mean change in central retinal thickness was a decrease of -166 μm in the monthly injection group; the MD compared with standard PRN was 21 μm (95% CI 6 to 32; 4 trials, 2215 participants; moderate-certainty evidence) and with treat-and extend was 22 μm (95% CI 37 to -81 μm; 2 trials, 635 participants; low-certainty evidence), in favor of monthly injection. Only one trial (498 participants) measured quality of life and reported no evidence of a difference between regimens, but data could not be extracted (low-certainty evidence). Both PRN regimens (standard and 'treat-and-extend') used fewer injections than monthly regimens (standard PRN: MD -4.6 injections, 95% CI -5.4 to -3.8; 4 trials, 2336 participants; treat-and-extend: -2.4 injections, 95% CI -2.7 to -2.1 injections; moderate-certainty evidence for both comparisons). Two trials provided cost data (1105 participants, trials conducted in the US and the UK). They found that cost differences between regimens were reduced if bevacizumab rather than aflibercept or ranibizumab were used, since bevacizumab was less costly (low-certainty evidence). PRN regimens were associated with a reduced risk of endophthalmitis compared with monthly injections (Peto odds ratio (OR) 0.13, 95% CI 0.04 to 0.46; 6 RCTs, 3175 participants; moderate-certainty evidence). Using data from all trials included in this review, we estimated the risk of endophthalmitis with monthly injections to be 8 in every 1000 people per year. The corresponding risk for people receiving PRN regimens was 1 in every 1000 people per year (95% CI 0 to 4). Three trials (1439 participants) compared an extended-fixed regimen (number of injections reported in only one large trial: 7.5 in one year) with monthly injections. There was moderate-certainty evidence that BCVA at one year was similar for extended-fixed and monthly injections (MD in BCVA change compared to extended-fixed group: -1.3 letters, 95% CI -3.9 to 1.3; RR of gaining 15 letters or more: 0.94, 95% CI 0.80 to 1.10). The change in central retinal thickness was a decrease of 137 μm in the monthly group; the MD with the extended-fixed group was 8 μm (95% CI -11 to 27; low-certainty evidence). The frequency of endophthalmitis was lower in the extended-fixed regimen compared to the monthly group, but this estimate was imprecise (RR 0.19, 95% CI 0.03 to 1.11; low-certainty evidence). If we assumed a risk of 8 cases of endophthalmitis in 1000 people receiving monthly injections over one year, then the corresponding risk with extended-fixed regimen was 2 in 1000 people (95% CI 0 to 9). Other evidence comparing different extended-fixed or PRN regimens yielded inconclusive results.

AUTHORS' CONCLUSIONS

We found that, at one year, monthly regimens are probably more effective than PRN regimens using seven or eight injections in the first year, but the difference is small and clinically insignificant. Endophthalmitis is probably more common with monthly injections and differences in costs between regimens are higher if aflibercept or ranibizumab are used compared to bevacizumab. This evidence only applies to settings in which regimens are implemented as described in the trials, whereas undertreatment is likely to be common in real-world settings. There are no data from RCTs on long-term effects of different treatment regimens.

Acute emotional stress as a trigger for intraocular pressure elevation in Glaucoma

Background

Stress-induced activation of the sympathetic nervous system leads to a cascade of metabolic reactions. Emotional stress is a more specific form of stress in which the stressor is a psychological response to a situation subjectively perceived as traumatic. Stress hormones can have a wide range of effects on the body, however, it is still unclear if and how it can affect ophthalmic physiology. This report presents a case of severe ocular hypertension in which emotional stress was the only cause elicited, and explores potential aggravating factors.

Case presentation

A 78-year-old, personality type A, lady with a history of pseudo-exfoliative glaucoma presented with an acute asymmetrical raise in intraocular pressure (IOP) immediately following a family breakdown. Her IOP had previously remained stable following a deep sclerectomy in the right eye and an Ex-PRESS shunt in the left eye. Her examination was entirely normal otherwise, with a patent filtration and diffuse bleb as confirmed with anterior segment OCT imaging. Near-normalisation of her IOP was observed within 24 h, concomitantly with the reduction of her stress levels. No other cause for the transient acute hypertensive episode were found.

Conclusions

This case report suggests that acute emotional stress could severely affect IOP in patients suffering from glaucoma. This could be important when looking after glaucoma patients. It would also suggest that the personnality types, and the emotional and social context are more factors to take into account in glaucoma studies. These observations are based on a single case report and would need to be verified on a larger scale.

Anti-vascular endothelial growth factor for neovascular age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is the most common cause of uncorrectable severe vision loss in people aged 55 years and older in the developed world. Choroidal neovascularization (CNV) secondary to AMD accounts for most cases of AMD-related severe vision loss. Intravitreous injection of anti-vascular endothelial growth factor (anti-VEGF) agents aims to block the growth of abnormal blood vessels in the eye to prevent vision loss and, in some instances, to improve vision.

OBJECTIVES

• To investigate ocular and systemic effects of, and quality of life associated with, intravitreous injection of three anti-VEGF agents (pegaptanib, ranibizumab, and bevacizumab) versus no anti-VEGF treatment for patients with neovascular AMD• To compare the relative effects of one of these anti-VEGF agents versus another when administered in comparable dosages and regimens SEARCH METHODS: To identify eligible studies for this review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Trials Register (searched January 31, 2018); MEDLINE Ovid (1946 to January 31, 2018); Embase Ovid (1947 to January 31, 2018); the Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to January 31, 2018); the International Standard Randomized Controlled Trials Number (ISRCTN) Registry (www.isrctn.com/editAdvancedSearch - searched January 31, 2018); ClinicalTrials.gov (www.clinicaltrials.gov - searched November 28, 2018); and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en - searched January 31, 2018). We did not impose any date or language restrictions in electronic searches for trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that evaluated pegaptanib, ranibizumab, or bevacizumab versus each other or versus a control treatment (e.g. sham treatment, photodynamic therapy), in which participants were followed for at least one year.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened records, extracted data, and assessed risks of bias. We contacted trial authors for additional data. We compared outcomes using risk ratios (RRs) or mean differences (MDs). We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 16 RCTs that had enrolled a total of 6347 participants with neovascular AMD (the number of participants per trial ranged from 23 to 1208) and identified one potentially relevant ongoing trial. Six trials compared anti-VEGF treatment (pegaptanib, ranibizumab, or bevacizumab) versus control, and 10 trials compared bevacizumab versus ranibizumab. Pharmaceutical companies conducted or sponsored four trials but funded none of the studies that evaluated bevacizumab. Researchers conducted these trials at various centers across five continents (North and South America, Europe, Asia, and Australia). The overall certainty of the evidence was moderate to high, and most trials had an overall low risk of bias. All but one trial had been registered prospectively.When compared with those who received control treatment, more participants who received intravitreous injection of any of the three anti-VEGF agents had gained 15 letters or more of visual acuity (risk ratio [RR] 4.19, 95% confidence interval [CI] 2.32 to 7.55; moderate-certainty evidence), had lost fewer than 15 letters of visual acuity (RR 1.40, 95% CI 1.27 to 1.55; high-certainty evidence), and showed mean improvement in visual acuity (mean difference 6.7 letters, 95% CI 4.4 to 9.0 in one pegaptanib trial; mean difference 17.8 letters, 95% CI 16.0 to 19.7 in three ranibizumab trials; moderate-certainty evidence) after one year of follow-up. Participants treated with anti-VEGF agents showed improvement in morphologic outcomes (e.g. size of CNV, central retinal thickness) compared with participants not treated with anti-VEGF agents (moderate-certainty evidence). No trial directly compared pegaptanib versus another anti-VEGF agent and followed participants for one year; however, when compared with control treatments, ranibizumab and bevacizumab each yielded larger improvements in visual acuity outcomes than pegaptanib.Visual acuity outcomes after bevacizumab and ranibizumab were similar when the same RCTs compared the same regimens with respect to gain of 15 or more letters of visual acuity (RR 0.95, 95% CI 0.81 to 1.12; high-certainty evidence) and loss of fewer than 15 letters of visual acuity (RR 1.00, 95% CI 0.98 to 1.02; high-certainty evidence); results showed similar mean improvement in visual acuity (mean difference [MD] -0.5 letters, 95% CI -1.5 to 0.5; high-certainty evidence) after one year of follow-up, despite the substantially lower cost of bevacizumab compared with ranibizumab. Reduction in central retinal thickness was less among bevacizumab-treated participants than among ranibizumab-treated participants after one year (MD -11.6 μm, 95% CI -21.6 to -1.7; high-certainty evidence); however, this difference is within the range of measurement error, and we did not interpret it to be clinically meaningful.Ocular inflammation and increased intraocular pressure (IOP) after intravitreal injection were the most frequently reported serious ocular adverse events. Researchers reported endophthalmitis in less than 1% of anti-VEGF-treated participants and in no cases among control groups. The occurrence of serious systemic adverse events was comparable across anti-VEGF-treated groups and control groups; however, the numbers of events and trial participants may have been insufficient to show a meaningful difference between groups (evidence of low- to moderate-certainty). Investigators rarely measured and reported data on visual function, quality of life, or economic outcomes.

AUTHORS' CONCLUSIONS

Results of this review show the effectiveness of anti-VEGF agents (pegaptanib, ranibizumab, and bevacizumab) in terms of maintaining visual acuity; studies show that ranibizumab and bevacizumab improved visual acuity in some eyes that received these agents and were equally effective. Available information on the adverse effects of each medication does not suggest a higher incidence of potentially vision-threatening complications with intravitreous injection of anti-VEGF agents compared with control interventions; however, clinical trial sample sizes were not sufficient to estimate differences in rare safety outcomes. Future Cochrane Reviews should incorporate research evaluating variable dosing regimens of anti-VEGF agents, effects of long-term use, use of combination therapies (e.g. anti-VEGF treatment plus photodynamic therapy), and other methods of delivering these agents.

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.

Induced pluripotent stem cell-based therapy for age-related macular degeneration

INTRODUCTION

In age-related macular degeneration (AMD), stem cells could possibly replace or regenerate disrupted pathologic retinal pigment epithelium (RPE), and produce supportive growth factors and cytokines such as brain-derived neurotrophic factor.  Induced pluripotent stem cells (iPSCs)-derived RPE was first subretinally transplanted in a neovascular AMD patient in 2014. Areas covered: Induced PSCs are derived from the introduction of transcription factors to adult cells under specific cell culture conditions, followed by differentiation into RPE cells. Induced PSC-derived RPE cells exhibit ion transport, membrane potential, polarized VEGF secretion and gene expression that is similar to native RPE. Despite having similar in vitro function, morphology, immunostaining and microscopic analysis, it remains to be seen if iPSC-derived RPE can replicate the myriad of in vivo functions, including immunomodulatory effects, of native RPE cells.  Historically, adjuvant RPE transplantation during CNV resections were technically difficult and complicated by immune rejection. Autologous iPSCs are hypothesized to reduce the risk of immune rejection, but their production is time-consuming and expensive.  Alternatively, allogenic transplantation using human leukocyte antigen (HLA)-matched iPSCs, similar to HLA-matched organ transplantation, is currently being investigated. Expert opinion: Challenges to successful transplantation with iPSCs include surgical technique, a pathologic subretinal microenvironment, possible immune rejection, and complications of immunosuppression.