Intraocular pressure abnormalities associated with central and hemicentral retinal vein occlusion

Influence of Smoking and Controlled Medical Conditions on the Risks of Branch Retinal Vein Occlusion in South Korea: A Population-Based Study

PURPOSE

To evaluate the effect of controlled medical conditions and risk of lifetime smoking history on the prevalence of branch retinal vein occlusion (BRVO) based on the Korea National Health and Nutrition Survey (KNHANES) database from 2017-2021.

METHODS

The study population consisted of individuals aged ≥ 40 years who had completed ophthalmological questionnaires, underwent comprehensive ophthalmological examinations, and had at least one good-quality readable fundus photograph. Age, sex, hypertension status, diabetes status, dyslipidemia status, body mass index status, a history of chronic kidney disease (CKD), a lifetime smoking history of ≥ 100 cigarettes, and glaucoma were subjected to univariate and multivariate logistic regression analyses.

RESULTS

The estimated prevalence (± standard error) of RVO was 0.5% (±0.1%). Significant risk factors were one-year increase in age, female sex, hypertension (stage 1, controlled, uncontrolled, and undiagnosed hypertension), underweight, pre-obesity, history of CKD, lifetime smoking history of ≥ 100 cigarettes, and glaucoma. Controlled diabetes decreased the risk of BRVO by 55% (odds ratio [OR] = 0.45, 95% confidence interval [CI] = 0.22-0.89, p = 0.022) and controlled hyper-high-density-lipoprotein (HDL)-cholesterolemia decreased the risk by 69% (OR = 0.31, 95% CI = 0.13-0.76, p = 0.010).

CONCLUSION

This study, for the first time, reported the association between lifetime smoking history of ≥ 100 cigarettes and BRVO in Korea. The risk of BRVO was lower in participants with controlled diabetes and hypo-HDL-cholesterolemia.

[Retinal Vein Occlusions]

As retinal vein occlusion is such a complex systemic disease, its underlying risk profile should be narrowed down individually. Ophthalmologists should always rule out glaucoma or ocular hypertension while also screening the patient for systemic vascular diseases or risk factors in particular. Intravitreally applied medication (VEGF inhibitors or steroids) and laser coagulation (focal or panretinal) or a combination thereof can be considered to treat such retinal anomalies.

Causal association between glaucoma and risk of retinal vascular occlusion: a Mendelian randomization study

OBJECTIVE

Retinal vein occlusion (RVO) leads to visual impairment, and risk factors may include glaucoma. Although some studies suggest a relationship between glaucoma and RVO, it is unknown whether this association is causal. We performed Mendelian randomization (MR) analyses to evaluate the causal contribution to RVO of five genetically predicted glaucoma conditions.

METHODS

We conducted two-sample univariable MR analysis using inverse variance weighting, weighted median, and MR-Egger methods. We obtained publicly available datasets of genome-wide association studies (GWAS) meta-analyses for glaucoma as the exposure and a GWAS for RVO in the Finn Gen biobank study as the outcome.

RESULTS

Genetically predicted glaucoma was causally associated with RVO risk (beta = 0.267, standard error [SE] = 0.052, odds ratio [OR] = 1.306, 95% confidence interval [CI]: 1.181-1.445). This association was supported by sensitivity analyses using weighted median (beta = 0.211, SE = 0.075, OR = 1.235, 95% CI: 1.067-1.429), weighted mode (beta = 0.491, SE = 0.132, OR = 1.633, 95% CI: 1.261-2.116), and MR-Egger (beta = 0.3900, SE = 0.138, OR = 1.476, 95% CI: 1.128-1.933) methods. MR analyses using the validation dataset obtained consistent results.

CONCLUSION

Our results indicated that glaucoma is likely causally associated with an increased risk of RVO. The current findings may help in determining the underlying mechanisms via which glaucoma affects the risk of RVO.

Optimizing open-angle glaucoma risk assessment in patients with retinal vein occlusions

PURPOSE

To evaluate factors associated with the diagnosis of open-angle glaucoma (OAG) after a retinal vein occlusion (RVO).

DESIGN

Retrospective, cross-sectional study.

METHODS

Patients diagnosed with OAG after RVO were matched 2:1 with RVO patients without prior glaucoma. Logistic regression identified factors linked to OAG diagnosis.

RESULTS

Of 1178 RVO patients without initial OAG, 51 (4.5%) were later diagnosed with OAG after an average of 5.5 ± 6.1 years. Screening tests for OAG were performed at a higher frequency in patients diagnosed with OAG compared with patients who never received this diagnosis (visual field [VF] testing 21.6% versus 10.8% (P = 0.073) and retinal nerve fiber layer [RNFL] imaging 52.9% versus 27.4% (P = 0.002), respectively). At the time of the first VF obtained after RVO, mean deviation averaged -10.3 dB in the affected eyes, compared with -5.0 dB in the fellow eyes (P < 0.001); in contrast, RNFL thickness was similar between eyes at the time of OAG diagnosis (72 µm versus 74 µm, P = 0.290). Predictive factors for OAG diagnosis included higher intraocular pressure (IOP) and cup-to-disc ratio (CDR) in the unaffected eye, and the absence of macular edema in the RVO-affected eye (R2 = 0.375, P < 0.001).

CONCLUSIONS

OAG is a significant risk factor for RVO. Our study reveals a reciprocal relationship between RVO and the development of OAG, highlighting the need for glaucoma risk assessment in all patients with RVOs to avoid delays in diagnosis and vision loss from glaucoma.

IMPLICATIONS OF COMPLETE POSTERIOR VITREOUS DETACHMENT IN EYES WITH CENTRAL RETINAL VEIN OCCLUSION

BACKGROUND/PURPOSE

To evaluate the status of the posterior vitreous hyaloid on presenting optical coherence tomography images of the macula and its relationship to clinical characteristics, treatment patterns, and outcomes in eyes with central retinal vein occlusion.

METHODS

This is a retrospective longitudinal cohort study of consecutive patients with acute, treatment-naive central retinal vein occlusion diagnosed between 2009 and 2021 who had at least 12 months of follow-up. Clinical characteristics, treatment patterns, and outcomes were analyzed between eyes stratified based on the presence or absence of a complete posterior vitreous detachment (PVD) on optical coherence tomography at presentation.

RESULTS

Of 102 acute, treatment-naive central retinal vein occlusions identified, 52 (51%) had complete PVD at presentation and 50 (49%) did not. Central subfield thickness was significantly lower in those with complete PVD (12 months: 284.9 ± 122.9 µ m vs. 426.8 ± 286.4 µ m, P < 0.001; last follow-up: 278 ± 127.9 vs. 372.8 ± 191.0 µ m, P = 0.022). One-year intravitreal injection burden was significantly less for those with a complete PVD than those without (5.1 ± 3.6 injections vs. 6.7 ± 3.3 injections, P = 0.013).

CONCLUSION

Central retinal vein occlusion with complete PVD on presentation had significantly lower central subfield thickness and 1-year injection burden. Assessment of the vitreomacular interface in central retinal vein occlusion may serve as a prognostic imaging biomarker.

Intraocular Pressure in Eyes With Retinal Vein Occlusion Compared With Fellow Eyes: Study of Comparative Treatments for Retinal Vein Occlusion 2 (SCORE2) Report 27

This cohort study investigates intraocular pressure (IOP) in eyes with retinal vein occlusion (RVO) compared with fellow, unaffected eyes.

Highlights on Genetic Polymorphism Associated with Thromboembolic Risk; Implications in Ophthalmic and Autoimmune Disorders—A Review

The present paper explores genetic polymorphism and its association with thromboembolic retinal venous disorders, such as central/hemi-retinal vein occlusion, as well as possible correlations with other ocular findings, such as closed angle glaucoma, but also with autoimmune general disorders. In this review, we are highlighting the importance of establishing a correspondence between all of the above, since they all have complex etiopathogeneses; sometimes, when all coexist together, they could generate effects that may be very difficult to manage. There are studies supporting that genetic polymorphism, such as the variant MTHFR A1298C, may increase the risk for developing glaucoma, especially in the heterozygote model. Being aware of all these aspects may prove to be useful in patients with several associated diseases, as a combined effort between several medical specialties may prove to the benefit of these patients. Our review, completed with an exemplifying clinical case, shows that it is necessary to raise awareness of all aspects of a complex medical situation, including the genetic one, of a patient being at risk for thromboembolic episodes, for preventing them or managing them promptly and properly in the future.

Retinal injury identified by overhead-mounted optical coherence tomography in two young children with infantile-onset glaucoma

PURPOSE

To report and characterize unexpected retinal findings identified by imaging with overhead-mounted optical coherence tomography (OCT) in 2 young children with infantile-onset glaucoma.

METHODS

Children with glaucoma were imaged during clinically indicated examinations under anesthesia using overhead-mounted HRA+OCT Spectralis with Flex module (Flex-OCT, Heidelberg, Germany) from February 2017 through February 2022. Imagers prioritized scans of the peripapillary retinal nerve fiber layer (pRNFL), optic nerve head, and macula. Children imaged before age 2 years with images adequate for evaluation were included. Age at glaucoma diagnosis, glaucoma type, highest intraocular pressure (IOP), corneal diameter (CD), and axial length (AL) were recorded.

RESULTS

A total of 41 children (71 eyes with glaucoma) were imaged before age 2 years. Macular imaging identified both inner and outer retinal thinning in 3 eyes of 2 young children (both eyes of a child with newborn primary congenital glaucoma (PCG) and 1 eye of a child with glaucoma following cataract surgery), which remained stable over time. These findings were present in 2 of 41 children (4.9%) and 3 of 71 eyes (4.2%) imaged with Flex-OCT. Neither highest IOP, CD, nor AL at imaging differentiated the 3 eyes with retinal changes from the larger group.

CONCLUSIONS

Three eyes of 2 young children with refractory glaucoma of different etiologies and highly elevated IOP demonstrated areas of inner and outer retinal thinning, consistent with retinal injury from probable prior macular ischemia. Unexpected retinal pathology identified on Flex-OCT imaging in infantile-onset glaucomas highlights the need for continued study of the pathophysiology of this disease.

Vessel Pulse Amplitude Mapping in Eyes With Central and Hemi Retinal Venous Occlusion

Purpose

The purpose of this study was to describe vessel pulse amplitude characteristics in eyes with central retinal vein occlusion (CRVO), hemiretinal vein occlusion (HVO), normal eyes (N1 N1), and the unaffected contralateral eyes of CRVO and HVO eyes (N1 CRVO and N1 HVO), as well as the unaffected hemivessels of HVO eyes (N2 HVO).

Methods

Ophthalmodynamometry estimates of blood column pulse amplitudes with modified photoplethysmography were timed against cardiac cycles. Harmonic analysis was performed on the vessel reflectance within 0.25 to 1 mm from the disc center to construct pulse amplitude maps. Linear mixed modeling was used to examine variable effects upon the log harmonic pulse amplitude.

Results

One hundred seven eyes were examined. Normal eyes had the highest mean venous pulse amplitude (2.08 ± 0.48 log u). CRVO had the lowest (0.99 ± 0.45 log u, P < 0.0001), followed by HVO (1.23 ± 0.46 log u, P = 0.0002) and N2 HVO (1.30 ± 0.59 log u, P = 0.0005). N1 CRVO (1.76 ± 0.34 log u, P = 0.52) and N1 HVO (1.33 ± 0.37 log u, P = 0.0101) had no significantly different mean amplitudes compared to N1 N1. Arterial amplitudes were lower than venous (P < 0.01) and reduced with venous occlusion (P < 0.01). Pulse amplitude versus amplitude over distance decreased along the N1 N1 vessels, with increasing slopes observed with CRVO (P < 0.01).

Conclusions

Pulse amplitude reduction and attenuation characteristics of arteries and veins in venous occlusion can be measured and are consistent with reduced vessel wall compliance and pulse wave transmission.

Translational Relevance

Retinal vascular pulse amplitudes can be measured, revealing occlusion induced changes, suggesting a role in evaluating the severity and progression of venous occlusion.

Biomechanical homeostasis in ocular diseases: A mini-review

Diabetes mellitus-induced hyperglycemia is responsible for multiple pathological ocular alternations from vasculopathy to biomechanical dyshomeostasis. Biomechanical homeostasis is crucial to maintain the normal physiological condition of the eyes. Biomechanical features vary in eye tissues regarding different anatomical positions, tissue components, and cellular functions. The disturbance in biomechanical homeostasis may result in different ocular diseases. In this review, we provide a preliminary sketch of the latest evidence on the mechano-environment of the eyeball and its possible influencing factors, thereby underscoring the relationship between the dyshomeostasis of ocular biomechanics and common eye diseases (e.g., diabetic retinopathy, keratoconus, glaucoma, spaceflight-associated neuro-ocular syndrome, retinal vein occlusion and myopia, etc.). Together with the reported evidence, we further discuss and postulate the potential role of biomechanical homeostasis in ophthalmic pathology. Some latest strategies to investigate the biomechanical properties in ocular diseases help unveil the pathological changes at multiple scales, offering references for making new diagnostic and treatment strategies targeting mechanobiology.

Central corneal thickness, axial length, anterior chamber and optic disc structure in patients with central and branch retinal vein occlusion

PURPOSE

To compare the central corneal thickness (CCT), the structural properties of the anterior chamber and optic disc in patients with central retinal vein occlusion (CRVO), branch retinal vein occlusion (BRVO), and controls.

MATERIAL AND METHODS

In this prospective study, 31 eyes of 31 CRVO patients (group 1) (mean age: 65.7 ± 10.2 male/female:16/15), 42 eyes of 42 BRVO patients (group 2) (mean age: 61.5 ± 9.9, male/female: 21/21), and 41 controls (mean age: 61.2 ± 15.3, male/female:15/26) were enrolled. Intraocular pressure (IOP), corrected IOP (IOPcorr), central corneal thickness (CCT), anterior chamber depth & volume (ACD & ACV), iridocorneal angle (ICA), axial length (AL), retinal nerve fiber layer (RNFL) thickness, ganglion cell layer (GCL) thickness, cup to disc ratio (C/D), cup & rim volume, the scleral canal diameter (SCD), and mean & pattern deviation in visual field of the eyes with CRVO/BRVO, their fellow eyes and control eyes were evaluated.

RESULTS

There was no significant difference in IOP among groups (p:0.239), while IOPcorr was significantly higher in eyes with CRVO compared with eyes with BRVO (p:0.003). Central corneal thickness was significantly thinner in CRVO than both BRVO and controls (p:0.005, p:0.002 respectively). The difference in the RNFL thickness was significant among groups (p:0.019), and it was detected significant between CRVO eyes and controls (p:0.05). Anterior chamber volume was lower in eyes with BRVO than in normal eyes (p:0.009). There was no significant difference in AL, ACD, rim volume, cup volume, GCL thickness, C/D ratio, ICA, and PSD among groups.

CONCLUSION

The patients with CRVO tend to have thinner corneas, and the evaluation of IOP and CCT can be overlooked during retinal follow-up. Intraocular pressure values corrected with CCT should always be take into account to prevent possible optic nerve damage.

Real-Life Efficacy of Bevacizumab Treatment for Macular Edema Secondary to Central Retinal Vein Occlusion according to Pro Re Nata or Treat-and-Extend Regimen in Eyes with or without Epiretinal Membrane

Purpose. To present real-life data of patients with macular edema (ME) secondary to central retinal vein occlusion (CRVO) treated with bevacizumab (BVZ); determine the possible influence of epiretinal membrane (ERM) on treatment efficacy; and compare treatment outcomes in a treat-and-extend regimen (TER) versus pro re nata (PRN). Methods. We carried out a retrospective analysis of 58 eyes (56 patients) with new-onset CRVO treated only with intravitreal bevacizumab according to TER or PRN. Outcome measures were best-corrected visual acuity (BCVA) and central retinal thickness (CRT) at baseline and 12 months after the first treatment, number of visits and injections, and presence of ERM confirmed by optical coherence tomography in the first 6 months. Results. At 12 months, the mean number of injections was 6.3 across all eyes, with significantly more injections given in TER ( $p<0.001$ ). Mean CRT improved from 627 μm to 359 μm ( $p<0.001$ ) in all eyes, with improvement noted in TER ( $p<0.001$ ), PRN ( $p<0.001$ ), ERM ( $p=0.003$ ), and non-ERM ( $p<0.001$ ) subgroups. The mean BCVA gain was +13.6 letters, and the mean BCVA improved from 0.81 to 0.54 LogMAR ( $p<0.001$ ) in all eyes. BCVA improvement from baseline was significant in TER ( $p<0.001$ ) and non-ERM ( $p<0.001$ ) but not in PRN ( $p=0.08$ ) or ERM ( $p=0.2$ ) subgroups. Seven eyes, all receiving PRN treatment, developed neovascularization. Conclusions. Intravitreal bevacizumab according to either PRN or TER resolved edema and stabilized vision in the first 12 months, with TER yielding significant visual improvement and avoiding neovascular complications. ERM had no influence on bevacizumab efficacy in reducing ME in CRVO during 12 months of treatment.

A narrative review on the association of high intraocular pressure and glaucoma in patients with retinal vein occlusion

BACKGROUND AND OBJECTIVE

Retinal vein occlusion (RVO) is a major cause of vision loss and elevated intraocular pressure (IOP), high ocular perfusion pressure, and glaucoma are known ophthalmic risk factors for RVO. The aim of this paper is to provide the update on the association and management of high IOP/glaucoma and RVO.

METHODS

A literature review was performed in PubMed and Medline until May 2022 utilizing specific keywords and cross-matched reference lists.

KEY CONTENT AND FINDINGS

The association of RVO with high IOP/glaucoma may be attributed to retinal ganglion cell loss due to retinal ischemia in high IOP and glaucoma. As new modalities showed, decreased optic disc perfusion, reduced density of blood vessels in the optic nerve head of glaucoma patients, changes in the peripapillary microvascular parameters, and decreased retinal nerve fiber layer (RNFL) thickness of the optic nerve head of eyes with RVO suggest a common pathway between RVO and glaucoma. Literature suggests the close follow up for glaucoma development among patients with non-arteriovenous (AV) crossing (optic cup or optic nerve sited) RVO in fellow eye and management of elevated IOP among RVO cases treated with anti-vascular endothelial growth factor (VEGF) antibodies/corticosteroids and those with preexisting primary open angle glaucoma (POAG).

CONCLUSIONS

Determining potential patient responses to treatment and considering therapeutic options are challenging among patients with RVO and glaucoma. However, IOP lowering managements in preventing IOP spikes in patients with preexisting glaucoma and early treatment of macular edema in eyes with RVO is recommended.

Association of primary angle-closure disease in patients with retinal vein occlusion in North Indian population

Purpose

To determine the association of primary angle-closure disease (PACD) in patients with retinal vein occlusion (RVO) at a tertiary eye care center in North India.

Methods

It is a cross-sectional, observational study. Sixty consecutive patients with retinal vein occlusion within a period of one year from a single tertiary eye care center were enrolled. Detailed history, slit-lamp examination of the anterior segment, intraocular pressure measurement by applanation tonometry, gonioscopy and fundus examination were done. Anterior chamber depth and axial length were also measured.

Results

Among the 60 patients, 29 were males (48.3%) and 31 females (51.6%). Twenty-seven (45%) of them had central retinal vein occlusion (CRVO) and 33 (55%) had branch retinal vein occlusion (BRVO). Forty percent of patients with RVO had PACD. Relative risk of PACD was 1.71 times in patients with CRVO as compared to BRVO. Risk of glaucoma was 49% more in CRVO than BRVO. Probability of PACD was more in patients of RVO who had diabetes and CAD as comorbidity.

Conclusion

The association between PACD and RVO is less known. PACD can be one of the risk factors for the development of RVO. A comprehensive examination and detailed angle evaluation of both of the eyes should be done in all cases of RVO, in addition to investigating for systemic risk factors. However, larger population-based studies would be required to prove it as an independent risk factor.

ENDOTHELIN-1 AS A RISK FACTOR IN RETINAL VEIN OCCLUSION

PURPOSE

Retinal vein occlusion (RVO) risk factors largely coincide with cardiovascular risk factors. Endothelin-1 (ET-1), the most potent vasoconstrictor with proinflammatory properties, is a known cardiovascular risk factor. In this study, we explore the role of serum ET-1 as a potential risk factor for RVO.

METHODS

Endothelin-1 serum levels were measured in patients with RVO and control subjects. Samples were measured using the sandwich enzyme-linked immunosorbent assay for the quantitative determination of human big endothelin-1 (Biomedica Group, Austria).

RESULTS

The study consisted of 147 RVO patients and 150 control subjects. Median serum ET-1 was significantly higher in RVO patients (0.26 pmol/L; range, 0.19-0.37 pmol/L) compared with control subjects (0.10 pmol/L; range, 0.05-0.22 pmol/L) (P < 0.0001) independent of the occlusion site. The difference remained significant after adjusting for arterial hypertension, diabetes mellitus, history of stroke, history of myocardial infarction, history of venous thromboembolism, glomerular filtration rate, and c-reactive protein.

CONCLUSION

In conclusion, our results suggest that ET-1 is a potential risk factor for all types of RVO.

Treatment of Atypical Clots

The term unusual site thrombosis refers to the occurrence of venous thromboembolism outside of the lower limbs and the pulmonary arteries. Unusual site thrombosis can virtually affect any venous segment, with the most common and/or clinically relevant sites including the upper limbs veins, the retinal veins, the splanchnic veins and the cerebral veins. Clinical features are obviously heterogeneous, while many predisposing factors are common, though with different prevalence among the various disorders. Antithrombotic therapy is prescribed to most patients, but the type, intensity, and duration of treatment vary both within and among patient groups. Increasing evidence is supporting the use of the direct oral anticoagulants in patients with upper limb deep vein thrombosis, cerebral vein thrombosis, and with splanchnic vein thrombosis. This article will review available evidence on the treatment of venous thrombosis occurring in unusual sites.

Reducing omission of eye drops during hospital admission

Background/aims

Chronic ophthalmic conditions, such as glaucoma and dry eye disease, are frequently encountered debilitating eye conditions that can lead to substantial reduction in vision and quality of life. However, there is ongoing evidence to suggest that topical ophthalmic therapy is inappropriately omitted on admission to hospital. The primary aim of this audit was to investigate the trust adherence to the National Institute for Health and Care Excellence guideline on the prescribing standard of eye drops during hospital admission. The secondary aim was to raise awareness and ensure successful compliance with national standards to reduce unintentional omission of eye drops on admission and subsequent complications.

Method

Electronic medical records of all medical and surgical adult inpatients were studied prospectively on two different occasions. The quality of documentation of eye drops in clerking notes, the length of time taken between the admission and prescription of eye drops, and the accuracy of the prescription were examined. Following the initial audit, interventions focusing on clinician education were implemented. This includes highlighting the importance of eye drops in all departmental mandatory introductory sessions and putting up posters on all the wards as prompts. The same data collection method was used in the reaudit.

Results

In the initial audit, 64 (mean age 81.8±8.9 years) patients with regular prescriptions for eye drops were identified; 38 (59.4%) patients had eye drops for dry eye disease only, 20 (31.3%) patients had eye drops for glaucoma only, and six (9.4%) patients had eye drops for both. In the reaudit, 57 (mean age 76.7±15.3 years) patients were identified; 42 (73.7%) patients had eye drops for dry eye disease only, 10 (17.5%) patients had eye drops for glaucoma only, and five (8.8%) patients had eye drops for both. Following the intervention, there was a significant improvement in documentation of ocular diagnosis and eye drops on clerking notes from 41% to 65% (P=0.008), and eye drop reconciliation within 24 hours of admission improved from 45% to 75% (P=0.0008). All patients (100%) received the correct eye drop prescription before and after the intervention.

Conclusions

Education is effective in promoting adherence to national guidelines and reducing the incidence of inappropriate omission of eye drops on admission to hospital.

Peripapillary retinal nerve fiber layer thickness in patients with unilateral retinal vein occlusion

This study evaluated longitudinal changes in peripapillary retinal nerve fiber layer (pRNFL) thickness in eyes affected with branch and central retinal vein occlusion (BRVO and CRVO, respectively) and fellow eyes. This retrospective case-control study included patients with newly diagnosed unilateral BRVO (46 patients) or unilateral CRVO (27 patients). The control group included 48 patients without abnormal findings on the fundus examination. Global and all-sector pRNFL thicknesses were greater in eyes with BRVO and CRVO than in fellow eyes at baseline; however, at 24 months, this difference remained only in the temporal sector of eyes affected with CRVO. Although the global pRNFL thicknesses of the fellow eyes in the BRVO and CRVO groups decreased significantly at 24 months compared to baseline (p = 0.001 and p = 0.011, respectively), there was no significant difference in the normal control group (p = 0.824). The global, inferior temporal, and inferior nasal pRNFL thicknesses at 12 and 24 months were significantly lower in the fellow eyes of the CRVO group than in those of the BRVO and normal control groups. The fellow eyes of patients with BRVO and CRVO suffered a significant reduction in pRNFL thickness compared to normal controls, indicating that they are susceptible to pRNFL damage.

THICKNESSES OF SCLERA AND LAMINA CRIBROSA IN PATIENTS WITH CENTRAL RETINAL VEIN OCCLUSION

PURPOSE

To evaluate thicknesses of sclera and lamina cribrosa (LC) in central retinal vein occlusion (CRVO).

METHOD

Thirty-two patients with CRVO (mean age 62.2 ± 11.6 years, women/men 18/14) and 35 age- and sex-matched healthy volunteers were included into the study. Scleral thickness was measured at scleral spur and at 1 to 3 mm from scleral spur in four quadrants (temporal, nasal, super, and inferior) using anterior segment optical coherence tomography. Lamina cribrosa was measured using optic disk enhanced depth imaging optical coherence tomography.

RESULTS

The sclera was thicker in affected eyes of the CRVO group than healthy subjects at scleral spur in four quadrants (738.7 ± 30.9 µm vs. 702 ± 30.8 µm in temporal, 700.4 ± 19.7 µm vs. 673 ± 13.7 µm in superior, 693 ± 19.3 µm vs. 665.3 ± 24.2 µm in nasal, 810.7 ± 28.9 µm vs. 784.5 ± 23.7 µm in inferior quadrants, respectively; P < 0.05 for all). Lamina cribrosa thickness in affected eyes of the CRVO group was significantly higher than that of healthy subjects (285.2 ± 12.7 µm vs. 266.4 ± 10.7 µm, respectively; P < 0.01). The correlation between scleral thickness and LC thickness was moderate at scleral spur of temporal and superior quadrants of affected eyes (r = 0.510 and r = 0.420, respectively).

CONCLUSION

Thicknesses of sclera and LC are increased in the CRVO, which may play a role in the pathogenesis of the disease.

Cataract Surgery Is Not Associated with Decreased Risk of Retinal Vein Occlusion

Purpose

Design

Participants

Methods

Main Outcome Measure

Results

Conclusions

Changes in peripapillary and subfoveal choroidal thickness in patients with central retinal vein occlusion

PURPOSE

We sought to evaluate changes of mean peripapillary choroidal thickness (PCT) and subfoveal choroidal thickness (SFCT) over 12 months in patients with unilateral central retinal vein occlusion (CRVO).

METHODS

Our retrospective, observational study included 19 patients with treatment-naïve, unilateral CRVO who completed at least 12 months of follow-up period. Mean PCT and mean SFCT in CRVO-affected eyes and unaffected contralateral eyes were measured at each follow-up visit, and then compared. Differences between baseline and 12 months (ΔSFCT and ΔPCT) and percentage changes (ΔSFCT or ΔPCT/baseline×100%) were determined. We also investigated the predictive factors for visual outcome in the CRVO-affected eyes.

RESULTS

In the CRVO-affected eyes, mean PCT was 146.7±41.9 μm at baseline, and 106.5±24.2 μm at 12 months (P < 0.001). Mean PCT of the contralateral eyes was 129.8±42.6 μm at baseline and 124.6±39.7 μm at 12 months (P = 0.089). Mean SFCT of CRVO-affected eyes was 225.8±77.9 μm at baseline, and 199.4±66.6 μm at 12 months (P = 0.009). Mean SFCT of the contralateral eyes was 218.4±83.0 μm at baseline, and 208.4±78.1 μm at 12 months (P = 0.089). Δ PCT was -41.6±25.3 μm in the CRVO-affected eyes, and -5.2±5.8 μm in the contralateral eyes (P<0.001). % PCT was -24.9±14.0% in the CRVO-affected eyes, and -4.0±0.4% in the contralateral eyes (P = 0.001). Δ SFCT was -26.4±24.6 μm in the CRVO-affected eyes, and -9.5±16.7μm in the contralateral eyes (P = 0.016). % SFCT was -10.4±9.8% in the CRVO-affected eyes, and -3.4±6.4% in the contralateral eyes (P = 0.015). Among the various factors, BCVA at baseline (β = 0.797, P = 0.001) and % SFCT (β = 0.712, P = 0.001) were significantly associated with visual outcome at 12 months in the CRVO-affected eyes.

CONCLUSION

Both peripapillary and subfoveal choroidal thickness reduced significantly over 12 months in the CRVO-affected eyes, but not in the contralateral eyes. In addition, the absolute reduction amount and reduction ratio of PCT and SFCT were significantly greater in the CRVO-affected eyes than the contralateral eyes.

Intraocular pressure modifications in patients with acute central/hemicentral retinal vein occlusions

Intraocular pressure (IOP) modifications in patients with acute central/hemicentral retinal vein occlusions (RVOs) consist in IOP reductions and increases. The IOP reduction is due to a transitional hyposecretory phase of the aqueous humor, that increases gradually until 3mo after the venous occlusion onset, and then finally disappears after month 4th. The IOP increases lead to the ocular hypertension and glaucoma. The possible pathogenetic correlations between ocular hypertension/glaucoma and acute central/hemicentral RVOs have been classified into three groups: 1) the venous occlusion precedes the ocular hypertension/glaucoma causing neovascular glaucoma and secondary angle-closure glaucoma without rubeosis; 2) the ocular hypertension and the glaucoma precede the venous occlusion and favor its appearance (ocular hypertension, primary angle-closure, primary angle-closure glaucoma, and open angle glaucomas); and 3) the venous occlusion and the ocular hypertension/glaucoma are mostly age dependent appearances due to common vascular and collagen alterations, lacking a causal connection between the 2 conditions.

Optic Disc Vascular Density in Normal-Tension Glaucoma Eyes with or without Branch Retinal Vessel Occlusion

We analyzed the vascular densities (VDs) of the optic disc areas in eyes with normal-tension glaucoma (NTG) according to their branch retinal vessel occlusion (BRVO) status. The VDs of the optic discs and peripapillary areas of 68 NTG patients with BRVO (BRVO group; BRVO eyes and fellow eyes) and 37 patients with NTG alone (control eyes) were measured on angiographic images obtained via swept-source optical coherence tomography angiography. VDs were compared among groups and correlations were assessed. The VD of the optic disc large vessel was the highest in BRVO eyes, followed by the fellow eyes and controls (all P < 0.05). Conversely, small and medium vessel VD was in the opposite order (all P < 0.05). Large vessel VD was negatively correlated with small and medium vessel VD (r = −0.697, P < 0.001). Peripapillary VD was lower in the BRVO eyes than in the control and fellow eyes (P < 0.001 and P = 0.861, respectively). In conclusion, significant changes in the distribution of VDs for optic disc larger vessel and small and medium vessels were observed in both eyes of NTG patients with BRVO, compared to NTG patients without BRVO.

Glaucoma as a prognostic factor of central retinal vein occlusion: visual and anatomical outcomes and occurrence of ischaemic central retinal vein occlusion

PURPOSE

To compare the functional and anatomical outcomes of central retinal vein occlusion (CRVO) according to the presence of glaucoma before the onset of CRVO, and to assess whether pre-existing glaucoma affects the prognosis of CRVO in terms of development and conversion to ischaemic CRVO.

METHODS

In this retrospective cohort study, patients with treatment-naïve CRVO were enrolled between December 2009 and February 2019. The patients were classified into two groups according to the presence of pre-existing primary open-angle glaucoma at CRVO diagnosis. We reviewed medical records regarding basic demographics, ocular characteristics and treatments. The effects of pre-existing glaucoma on the occurrence of ischaemic CRVO were also investigated using Cox proportional hazard models.

RESULTS

Of 166 eyes from 166 patients, 26 (15.7%) had pre-existing glaucoma. The pre-existing glaucoma group revealed significantly older (69.4 ± 13.3 versus 56.5 ± 15.9) and lower BCVA at baseline (1.06 ± 0.75 versus 0.64 ± 0.58, logMAR) and final visits (1.56 ± 1.35 versus 0.64 ± 0.48, logMAR) (all p < 0.05) than non-glaucomatous group. In terms of perfusion status of CRVO, the glaucoma group showed higher incidence of ischaemic CRVO (30.8% versus 5.3%, p = 0.052) at initial and last visits as well as more disorganization of retinal inner layers (DRIL) at 3 months (76.0% versus 49.6%, p = 0.015). Pre-existing glaucoma (hazard ratio (HR) = 2.141, p = 0.014), lower vision at baseline (HR = 2.071, p = 0.001) and DRIL at 3 months (HR = 2.905, p = 0.011) were significant risk factors for the occurrence of ischaemic CRVO.

CONCLUSION

In patients with CRVO, pre-existing glaucoma was associated with poorer visual and anatomical outcomes, and played as a significant risk factor for the development and conversion to ischaemic CRVO with lower vision and presence of DRIL at early phase of CRVO.

Treatment of retinal vein thrombosis: what about anticoagulants?

Retinal vein occlusion is an important cause of vision loss. The current treatment options are mainly directed to the prevention of neovascular complications and few studies have addressed to potential use of anticoagulant agents and other interventions targeting the coagulation system. Herein we review the general aspects of this condition focusing on the potential benefits of anticoagulant treatment.

Neovascular glaucoma in patients with central retinal vein occlusion: A real-life study in the anti-VEGF era

PURPOSE

To investigate the characteristics and treatment patterns of patients developing a neovascular event (NE) in the anterior chamber secondary to central retinal vein occlusion (CRVO) in an ordinary clinical setting.

METHODS

In this retrospective real-life study, data from 243 eyes presenting with CRVO during 2012-2013 were collected. Maximum follow-up was 5 years. All patients that developed NE were included in the analysis.

RESULTS

Of 243 eligible patients, 72 (30%) either presented with or developed NE during the follow-up. In these 72 patients, 23 (32%) eyes already had evidence of NE at baseline. Twenty-eight eyes (39%) developed NE after discontinuation of intravitreal therapy for macular oedema (ME). In this subgroup, the NE occurred 15.6 ± 13.8 months after the baseline visit and 4.1 ± 2.6 months after the last injection. Final best-corrected visual acuity was 8.6 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in the group of patients presenting with NE compared to 8.1 ETDRS letters in the group that developed NE later on. Of the patients presenting with intraocular pressure (IOP) below 30 mmHg, 3/29 (10%) needed subsequent cyclodiode laser therapy compared to 35/43 (81%) patients with a baseline IOP above 30 mmHg (p < 0.001).

CONCLUSIONS

In a clinical setting, many patients show evidence of NE already at the first visit. A substantial part of patients develops NE a long time after presentation, commonly a few months after discontinuation of intravitreal therapy for ME. The visual prognosis is similar for patients presenting with NE and patients developing NE during follow-up. A high baseline IOP predicts the need for subsequent pressure-lowering procedures.

Venous stasis retinopathy in a ten-year-old boy with ocular hypertension: a case report

Background

Central retinal vein occlusion is a variable disease pattern. Preliminary stages of a complete occlusion of the central vein, wich are subsumed under the term venous stasis retinopathy, may occur as transient blurred vision and with subtle alterations of the fundus. Course and prognosis are benign, visual acuity usually recovers. By now, venous stasis retinopathy in children due to Valsalva maneuver has not been described in literature yet.

Case presentation

We present an impressive case of venous stasis retinopathy in a 10-year-old boy with ocular hypertension and megalocornea due to increased intraocular pressure provoked by Valsalva maneuver. Main symptom was transient blurred vision in the left eye. The intraocular pressure was 28 mmHg, fundus exam revealed tortuous veins and a flame shaped hemorrhage at 7 o’clock. Total recovery under topical antiglaucomatous therapy could be observed after 1 month.

Conclusions

Acute increase in intraocular pressure, provoked by Valsalva maneuver is a risk factor for venous stasis retinopathy. Further general and vascular risk factors should be ruled out by extensive examination. Children with ocular hypertension might be at higher risk for impending vein occlusion as shown in this case.

Central Retinal Vessel Trunk Caliber Changes After Short-term Intraocular Pressure Elevation

PRECIS

After a short-term intraocular pressure (IOP) elevation, the central retinal vein caliber may be widened at lower IOP rise levels, while be compressed at higher IOP rise values.

PURPOSE

The purpose of this study was to investigate changes in the calibers of the central retinal vein trunk (CRVT) and central retinal artery trunk (CRAT) trunk during a short-term elevation of IOP.

METHODS

A prospective observational study. Acute primary angle-closure suspects underwent a dark room prone provocative test (DRPPT) for 2 hours. Before and at the end of the test, tonometry, swept-source optical coherence tomography, and nonmydriatic fundus photography were performed. The calibers of the CRVT and CRAT were measured on the fundus photos taken at baseline and at the end of the DRPPT.

RESULTS

The study included 101 eyes (61 individuals; mean age: 54.8±9.3 y; range: 30 to 70 y) which showed an increase in IOP by 9.6±9.0 mm Hg (range: 2.3 to 46.7 mm Hg). From baseline to the end of the DRPPT, the mean CRVT caliber increased from 101.8±25.9 to 107.7±26.6 μm (P<0.001), while the CRAT caliber did not differ significantly (110.3±24.2 vs. 109.7±21.5 μm; P=0.54) during the test. The CRVT widening was larger in the subgroup with IOP rise of <6 mm Hg than in the subgroup with an IOP rise of 6 to 15 mm Hg, while in the subgroup with an IOP rise of >15 mm Hg the CRVT caliber did not change significantly (P=0.20) during the test.

CONCLUSIONS

A physiological short-term IOP rise at lower levels of IOP elevation led to a widening of the CRVT, while at higher IOP values, the further IOP-rise may have compressed the retinal vein. Because of higher intraluminal pressure values, the retinal artery diameters were not affected by the IOP-rise.

Comparison of lamina cribrosa properties and the peripapillary vessel density between branch retinal vein occlusion and normal-tension glaucoma

PURPOSE

To compare the properties of the lamina cribrosa (LC) and the peripapillary vessel density between branch retinal vein occlusion (BRVO) and normal-tension glaucoma (NTG), using swept-source optical coherence tomography and optical coherence tomography angiography.

METHODS

This retrospective study included 21 eyes of 21 patients with BRVO and 43 eyes of 43 patients with NTG who were treated from June 2016 to September 2017. The anterior LC depth (ALCD) and LC thickness (LCT) at the mid-superior, central, and mid-inferior levels; the mean difference in ALCD; and the peripapillary vessel density in the superficial and deep capillary plexuses and the choriocapillaris were compared between groups.

RESULTS

ALCD at the mid-superior, central, and mid-inferior levels was significantly greater in the NTG group (P < 0.05), while LCT was comparable between the groups. The mean difference in ALCD was significantly greater in the BRVO group (P = 0.03). The peripapillary vessel density in the superotemporal segment of the superficial capillary plexus was significantly lower in the BRVO group, while the density in all segments of the choriocapillaris was significantly lower in the NTG group (P < 0.05 for all).

CONCLUSIONS

Our findings demonstrate that BRVO and NTG have different LC structures and peripapillary vessel densities.

Sequential multiple retinal vein occlusions and transient ischemic attack in MTHFR polymorphism and protein S deficiency

BACKGROUND

The C677T variant of the MTHFR (5,10-Methylenetetrahydrofolate reductase) gene is associated with increased susceptibility to homocystinuria (OMIM#236250), neural tube defects (OMIM#601634), schizophrenia (OMIM#181500), thromboembolism (OMIM#188050), and vascular diseases. Protein S deficiency is also associated with an increased risk of thromboembolism from reduced thrombin generation. In this report, we describe the case of a patient who presented with multiple retinal vein occlusions likely caused by an underlying combination of a homozygous MTHFR C677T variant and protein S deficiency.

METHODS

We performed 8 years of continuous ophthalmic follow-up of one patient diagnosed with central retinal vein occlusion. Peripheral blood was collected for metabolic evaluation and hypercoagulability assessment. Targeted gene sequencing was used for genetic diagnosis. Examination of the retinal vasculature was performed through dilated funduscopic examination, digital color fundus and ultrawide-field color fundus photography, spectral domain optical coherence tomography, and fluorescein angiography.

RESULTS

Sequential retinal vein occlusions and a transient ischemic attack were observed during the follow-up period. Targeted gene sequencing by PCR identified the homozygous MTHFR C677T variant. The metabolic profile indicated low-protein S activity, high levels of vitamin B6, and LDL cholesterol consistent with her hypercoagulable state. Prescription of low-dose aspirin and atorvastatin for hypercholesterolemia resulted in no further neovascularization, leakage, or vein occlusion.

CONCLUSION

Retinal vein occlusions associated with the MTHFR C677T variant and protein S deficiency may signal impending systemic thromboembolic episodes and warrant aggressive preventative measures.

Incidence of Open-angle Glaucoma in Newly Diagnosed Retinal Vein Occlusion: A Nationwide Population-based Study

PURPOSE

The purpose of this study was to compare the incidence of open-angle glaucoma (OAG) in patients with newly diagnosed retinal vein occlusion (RVO) with that in the general population in order to determine the association between OAG and RVO.

METHODS

The Korean Health Insurance Review and Assessment (HIRA) data from 2011 through 2015 was analyzed in order to determine the incidence rates of OAG in the general population and in patients with newly diagnosed RVO based on the diagnostic code. The standardized incidence ratios (SIRs) of OAG in patients with RVO were determined with respect to the age- and sex-matched general population.

RESULTS

The incidence rate of OAG in the general population during the 3 years (2013 to 2015) was 233.98 per 100,000 person-years (95% CI, 233.21-234.76). A total of 31,722 patients with newly diagnosed RVO were identified in 2012 as the population at risk. The incidence rate of OAG in patients with RVO during the 3-year follow-up period was 1829.43 per 100,000 person-years (95% CI, 1745.49-1917.42). The expected incidence of OAG in patients with RVO was 433.69 during the 3-year follow-up period. On the other hand, the observed incidence of OAG was 1,741. The SIR of OAG in patients with RVO with reference to the general population was 4.01 (95% CI, 3.83-4.20).

CONCLUSIONS

The incidence rate of OAG in patients with RVO is significantly higher than that in the general population.

Clinical Features of Combined Central Retinal Artery and Vein Occlusion

PURPOSE

To describe the clinical features of combined central retinal artery and vein occlusion (CCRAVO).

METHODS

This retrospective study included 33 admitted patients (33 eyes) who had CCRAVO. Clinical data, such as age, gender, best-corrected visual acuity (BCVA), intraocular pressure (IOP), findings on fundus color photography and fundus fluorescein angiography (FFA), and information about follow-up, were collected and analyzed.

RESULTS

The age of the patients with CCRAVO ranged from 22 to 78 years, with a mean of 48.8 ± 14.1 years. At presentation, BCVA of the involved eyes ranged from no light perception (NLP) to 20/20. In addition, 45.5% (15/33) of the eyes had BCVA of finger counting (FC) or below, whereas 12.1% (4/33) had BCVA of 20/60 or above. The IOP was lower in the involved eyes than in the fellow eyes (15.0 ± 3.0 mmHg vs. 16.4 ± 2.3 mmHg, p=0.03). Ophthalmoscopic examination showed changes in both central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO), including retinal hemorrhage, retinal ischemic whitening, optic disc hyperemia and/or edema, venous dilation and tortuosity, cotton wool spot (CWS), and Roth's spot. FFA showed prolonged arm-to-retina time (ART) and retinal arteriovenous passage time (RAP) (17.1 ± 4.9 s and 12.1 ± 8.8 s, respectively). Capillary nonperfusion (CNP) was seen in 21 eyes (63.6%), and in 14 (42.2%) of these, CNP was larger than 10 disc areas. At 2 to 3 weeks after presentation, BCVA improved in 23 eyes (71.9%) and further deteriorated in 5 eyes (15.6%). Retinal ischemic whitening improved in more than half of the eyes, whereas retinal hemorrhage increased in nearly half of the eyes. Follow-up ranged from 6 to 56 months. Seven patients were lost to follow-up. At final follow-up, six eyes had a visual acuity of 20/60 or greater, but 6 eyes had FC or worse. Four eyes developed neovascularization on follow-up.

CONCLUSION

CCRAVO is a sight-threatening entity. Manifestations of CRAO and CRVO can be seen simultaneously in the early stage of disease, and CRVO may play a more important role in the development of CCRAVO.

Association of glaucoma with risk of retinal vein occlusion: A meta-analysis

To summarize epidemiological evidences on the association between glaucoma and the risk of retinal vein occlusion (RVO). Relevant studies were identified by searching in PubMed, EMBASE and Cochrane until February 2018. Fifteen eligible observational studies were aggregated in this analysis. All results were analysed and pooled using random effects models with 95% confidence intervals (CI). In all studies, the odds ratio (OR) of glaucoma as a risk factor for RVO was 4.01 (95% CI: 3.28-4.91). In RVO subtype-differentiated subgroup analyses (six studies), the pooled OR showed that glaucoma was associated with central retinal vein occlusion (CRVO) (OR: 6.21; 95% CI: 4.64-8.31), branch retinal vein occlusion (BRVO) (OR: 2.38; 95% CI: 1.77-3.19) and hemiretinal vein occlusion (HRVO) (OR: 4.60; 95% CI: 2.26-9.35). In glaucoma-classified subgroup analyses (five studies), primary open-angle glaucoma (POAG) (OR: 5.03; 95% CI: 3.97-6.37) and chronic open-angle glaucoma (COAG) (OR: 2.36; 95% CI: 1.39-4.02) were significant risk factors for RVO development. There was a plausible relationship between primary angle closure glaucoma (PACG) and RVO risk (OR: 1.85; 95% CI: 0.41-8.35); to be precise, the OR was 5.3 in PACG and CRVO risk (95% CI: 1.04-26.95; p = 0.045), while the OR was 0.65 in PACG and BRVO risk (95% CI: 0.07-6.27; p = 0.707). To sum up, this meta-analysis shows that glaucoma is associated with the risk of RVO. Glaucoma should be kept in mind when investigating patients with RVO in the clinic.

Vitrectomy for macular edema due to retinal vein occlusion

Purpose: To determine the long-term outcomes of vitrectomy for the macular edema associated with a retinal vein occlusion (RVO).

Methods: This was a retrospective, consecutive, interventional case series. The intraoperative procedures included internal limiting membrane peeling, arteriovenous sheathotomy, radial optic neurotomy, and intravitreal triamcinolone acetonide injection at the end of the surgery. The main outcome was the best-corrected visual acuity (BCVA).

Results: Eight hundred and fifty-four eyes of 854 patients were studied. The eyes consisted of 602 with branch RVO (BRVO), 74 with hemi-central RVO (hemi-CRVO), 87 with nonischemic central retinal vein occlusion (CRVO), and 91 with ischemic CRVO. The mean follow-up period was 68.6 months with a range of 12 to 262 months. The mean BCVA was significantly improved at the final visit (P<0.0001 to 0.0016). The final BCVA improved in 74.4% of the BRVO eyes, in 58.1% of the hemi-CRVO eyes, in 57.4% of the nonischemic CRVO eyes, and in 51.6% of the ischemic CRVO eyes. Multiple regression analysis showed there was no significant relationship between the intraoperative combined procedures and the final BCVA.

Conclusions: The results indicate that the type of RVO is significantly associated with the final BCVA, and vitrectomy is a treatment option to improve and maintain BCVA for a long term.

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.

Primary angle closure and primary angle closure glaucoma in retinal vein occlusion

PURPOSE

To investigate the frequency of primary angle closure (PAC) and primary angle closure glaucoma (PACG) in patients with retinal vein occlusion (RVO) based on a hospital population.

METHODS

A total of 375 consecutive cases newly diagnosed with RVO by fluorescein fundus angiography at a single eye centre in Peking were reviewed. Gonioscopy was performed in all patients. Glaucoma was diagnosed according to the criteria of the International Society of Geographical and Epidemiological Ophthalmology. Retinal vein occlusion was classified as central retinal vein occlusion (CRVO), hemicentral retinal vein occlusion (HRVO), or branch retinal vein occlusion (BRVO), and as arteriovenous crossing RVO (AV-RVO), optic cup RVO (OC-RVO), optic nerve RVO without optical nerve head swelling (NONHS-RVO), or RVO with optical nerve head swelling (ONHS-RVO) based on the site of venous occlusion. Percentage of PAC or PACG for each type of RVO were calculated.

RESULTS

PACG had a frequency of 4.1% [95% confidence interval (CI) 2.2-6.9%] in 317 RVO patients [5.3% (95% CI 2.0-11.2%) in CRVO, 8.8% (95% CI 1.9-23.7%) in HRVO, and 1.9% (95% CI 0.4-5.4%) in BRVO]. Primary angle closure (PAC) had a frequency of 2.9% (95% CI 1.4-5.5%) in RVO. PAC/PACG had a frequency of 11.5% (95% CI 6.3-18.9%) in CRVO, 8.8% (95% CI 1.9-23.7%) in HRVO and 3.1% (95% CI 1.0-7.1%) in BRVO. PAC/PACG was significantly more prevalent in NONHS-RVO [18.9% (95% CI 9.4-32.0%)] than in ONHS-RVO [6.5% (95% CI 2.1-14.5%)], AV-RVO [3.1% (95% CI 0.9-7.8%)], and OC-RVO [2.3% (95% CI 0.1-12.3%)].

CONCLUSION

The overall frequency of PAC/PACG was much higher in patients with RVO (especially CRVO) than that in the general population. Eyes with PAC/PACG may undergo mechanical changes in the lamina cribrosa of the optic disc, resulting in RVO. Angle-closure conditions should be borne in mind when investigating Chinese patients with RVO.

Management of the open angle glaucoma in patients with central/hemicentral retinal vein occlusions

AIM

To prospectively assess the cumulative prevalence and management of open angle glaucoma (OAG), including primary open angle glaucoma (POAG) with high and normal-pressure, as well as pseudoexfoliative glaucoma (PEXG), in patients with central/hemicentral retinal vein occlusions (RVOs) over a 3-year follow-up period.

METHODS

The study encompassed 57 patients with unilateral acute central/hemicentral RVOs. A complete ophthalmic examination of both eyes was undertaken for all patients. Patients with OAGs associated with central/hemicentral RVOs were treated with the current ocular hypotensive medications used worldwide and/or surgery and aimed to reduce the intraocular pressure (IOP) by 30% from baseline values for the 3 OAG forms existing in our series. The cumulative prevalence of OAG and the efficacy of treatment were evaluated.

RESULTS

OAG was observed in 3 clinical forms, namely, POAG with increased IOP in 4 patients, POAG with normal IOP in 3 patients, and PEXG in 3 patients. The cumulative prevalence of OAG was 19.6% (95%CI: 8.7-30.5). Using available ocular hypotensive medications (8 patients) and trabeculectomy (2 patients), the IOP decreased significantly from 24.3±4.36 mm Hg to 16.55±2.85 mm Hg, a reduction of 31.89% compared with baseline values. Glaucoma progression was not detected in any of the cases.

CONCLUSION

The high value of the cumulative prevalence of OAG is a risk factor for the development of venous occlusion. The treatment of glaucoma prevented its progression over a follow-up period of 3y.

Central retinal artery occlusion

The pathogeneses, clinical features, and management of central retinal artery occlusion (CRAO) are discussed. CRAO consists of the following four distinct clinical entities: non-arteritic CRAO (NA-CRAO), transient NA-CRAO, NA-CRAO with cilioretinal artery sparing, and arteritic CRAO. Clinical characteristics, visual outcome, and management very much depend upon the type of CRAO. Contrary to the prevalent belief, spontaneous improvement in both visual acuity and visual fields does occur, mainly during the first 7 days. The incidence of spontaneous visual acuity improvement during the first 7 days differs significantly (P < 0.001) among the four types of CRAO; among them, in eyes with initial visual acuity of counting finger or worse, visual acuity improved, remained stable, or deteriorated in NA-CRAO in 22%, 66%, and 12%, respectively; in NA-CRAO with cilioretinal artery sparing in 67%, 33%, and none, respectively; and in transient NA-CRAO in 82%, 18%, and none, respectively. Arteritic CRAO shows no change. Recent studies have shown that administration of local intra-arterial thrombolytic agent not only has no beneficial effect but also can be harmful. Investigations to find the cause and to prevent or reduce the risk of any further visual problems are discussed. Prevalent multiple misconceptions on CRAO are discussed.

Retinal oximetry and systemic arterial oxygen levels

PURPOSE

Continuous peripheral pulse oximetry for monitoring adequacy of oxygenation is probably the most important technological advance for patients' monitoring and safety in the last decades. Pulse oximetry has the disadvantage of measuring the peripheral circulation, and the only mean to measure oxygen content of the central circulation is by invasive technology. Determination of blood oxyhaemoglobin saturation in the retinal vessels of the eye can be achieved noninvasively through spectrophotometric retinal oximetry which provides access to the central nervous system circulation. The aim of the thesis was to determine whether retinal oximetry technique can be applied for estimation of the central nervous system circulation which until now has only been possible invasively. This was achieved by measuring oxyhaemoglobin saturation in three adult subject study groups: in people with central retinal vein occlusion (CRVO) to observe local tissue hypoxia, in patients with severe chronic obstructive pulmonary disease (COPD) on long-term oxygen therapy to observe systemic hypoxaemia and in healthy subjects during hyperoxic breathing to observe systemic hyperoxemia. In addition, the fourth study that is mentioned was performed to test whether retinal oximetry is feasible for neonates.

METHODS

Retinal oximetry in central retinal vein occlusion: Sixteen subjects with central retinal vein occlusion participated in the study. The oxyhaemoglobin saturation of the central retinal vein occlusion affected eye was compared with the fellow unaffected eye. Retinal oximetry in healthy people under hyperoxia: Thirty healthy subjects participated in the study, and the oxyhaemoglobin saturation of retinal arterioles and venules was compared between normoxic and hyperoxic breathing. Retinal oximetry in severe chronic obstructive pulmonary disease: Eleven patients with severe chronic obstructive pulmonary disease participated in the study. Retinal oximetry measurements were made with and without their daily supplemental oxygen therapy. Retinal arteriolar oxyhaemoglobin saturation when inspiring ambient air was compared with blood samples from the radial artery and finger pulse oximetry and healthy controls. The healthy control group was assembled from our database for comparison of oxyhaemoglobin saturation of retinal arterioles and venules during the ambient air breathing. The retinal oximeter is based on a conventional fundus camera and a specialized software. A beam splitter coupled with two high-resolution digital cameras allows for simultaneous acquisition of retinal images at separative wavelengths for calculation of oxyhaemoglobin saturation. In addition, retinal images of 28 full-term healthy neonates were obtained with scanning laser ophthalmoscope combined with modified Oxymap analysis software for calculation of the optical density ratio and vessel diameter RESULTS: Retinal oximetry in central retinal vein occlusion: Mean retinal venous oxyhaemoglobin saturation was 31 ± 12% in CRVO eyes and 52 ± 11% in unaffected fellow eyes (mean ± SD, n = 14, p < 0.0001). The arteriovenous oxygen difference (AV-difference) was 63 ± 11% in CRVO eyes and 43 ± 7% in fellow eyes (p < 0.0001). The variability of retinal venous oxyhaemoglobin saturation was considerable within and between eyes affected by CRVO. There was no difference in oxyhaemoglobin saturation of retinal arterioles between the CRVO eyes and the unaffected eyes (p = 0.49). Retinal oximetry in healthy people under hyperoxia: During hyperoxic breathing, the oxyhaemoglobin saturation in retinal arterioles increased to 94.5 ± 3.8% as compared with 92.0 ± 3.7% at baseline (n = 30, p < 0.0001). In venules, the mean oxyhaemoglobin saturation increased to 76.2 ± 8.0% from 51.3 ± 5.6% (p < 0.0001) at baseline. The AV-difference was markedly lower during hyperoxic breathing as compared with the normoxic breathing (18.3 ± 9.0% versus 40.7 ± 5.7%, p < 0.0001). Retinal oximetry in severe chronic obstructive pulmonary disease: During ambient air breathing, chronic obstructive pulmonary disease subjects had significantly lower oxyhaemoglobin saturation than healthy controls in both retinal arterioles (87.2 ± 4.9% versus 93.4 ± 4.3%, p = 0.02, n = 11) and venules (45.0 ± 10.3% versus 55.2 ± 5.5%, p = 0.01) but the AV-difference was not markedly different (p = 0.17). Administration of their prescribed oxygen therapy significantly increased the oxyhaemoglobin saturation in retinal arterioles (87.2 ± 4.9% to 89.5 ± 6.0%, p = 0.02) but not in venules (45.0 ± 10.3% to 46.7 ± 12.8%, p = 0.3). Retinal oximetry values were slightly lower than finger pulse oximetry (mean percentage points difference = -3.1 ± 5.5) and radial artery blood values (-5.0 ± 5.4). Retinal oximetry study in neonates: The modified version of the retinal oximetry instrument estimated the optical density ratio in retinal arterioles to be 0.256 ± 0.041 that was significantly different from the 0.421 ± 0.089 in venules (n = 28, p < 0.001, paired t-test). The vascular diameter of retinal arterioles was markedly narrower than of venules (14.1 ± 2.7 and 19.7 ± 3.7 pixels, p < 0.001).

CONCLUSION

The results of this thesis indicate that spectrophotometric retinal oximetry is sensitive to both local and systemic changes in oxyhaemoglobin saturation. Retinal oxyhaemoglobin saturation values are slightly lower than radial artery blood sample and finger pulse oximetry values. The discrepancies between the different modalities are expected to derive from countercurrent exchange between central retinal artery and vein within the optic nerve but calibration issues cannot be excluded as contributing to this difference. Despite these differences, the findings indicate the potential of retinal oximetry for noninvasive real-time measurements of oxyhaemoglobin saturation in central nervous system vessels. Following calibration upgrade and technological improvement, verification retinal oximetry may potentially be applied to critically ill and anaesthesia care patients. The study on combined scanning laser ophthalmoscope and retinal oximetry supports the feasibility of the technique for oximetry analysis in newly born babies.

Venous thrombosis in unusual sites: A practical review for the hematologist

Thrombosis of unusual venous sites encompasses a large part of consultative hematology and is encountered routinely by practicing hematologists. Contrary to the more commonly encountered lower extremity venous thrombosis and common cardiovascular disorders, the various thromboses outlined in this review have unique presentations, pathophysiology, workup, and treatments that all hematologists should be aware of. This review attempts to outline the most up to date literature on cerebral, retinal, upper extremity, hepatic, portal, splenic, mesenteric, and renal vein thrombosis, focusing on the incidence, pathophysiology, provoking factors, and current recommended treatments for each type of unusual thrombosis to provide a useful and practical review for the hematologist.

Ocular hypertension in patients with central/hemicentral retinal vein occlusions: cumulative prevalence and management

AIM

To prospectively evaluate the cumulative prevalence and the management of ocular hypertension (OH) in patients with unilateral acute central/hemicentral retinal vein occlusions (C/HCRVOs) over the course of 3y.

METHODS

The study included 57 patients with unilateral acute C/HCRVOs. All patients underwent a comprehensive ophthalmological examination of both eyes. OH associated with C/HCRVO in patients showing a score >5% for the risk of conversion to primary open angle glaucoma (POAG) was treated with OH medication. The treatment aimed for a decrease in intraocular pressure (IOP) to <21 mm Hg with a >22% reduction from the initial values. The cumulative prevalence of OH and the effectiveness of treatment assessed by the cumulative prevalence of conversion from OH to POAG, were estimated.

RESULTS

Fifteen patients had OH associated with C/HCRVOs, the cumulative prevalence of OH was 29.4% (95% confidence interval, 16.9-41.9). The mean value of the risk score of OH conversion to POAG for the 5 subsequent years was 11.7%±5.4%. The IOP significantly decreased from 25.67±2.16 mm Hg to 18.73±2.96 mm Hg. None of the OH patients converted to POAG during the follow-up period.

CONCLUSION

The increased cumulative prevalence of OH in C/HCRVO patients indicates that OH is a risk factor for the appearance of venous occlusion. Patients with OH associated with C/HCRVO must be considered to be at high risk for conversion to POAG. Treatment with OH medications prevented conversion to POAG during the 3-year follow-up.

SIGNIFICANT REDUCTION OF PERIPAPILLARY CHOROIDAL THICKNESS IN PATIENTS WITH UNILATERAL BRANCH RETINAL VEIN OCCLUSION

PURPOSE

To evaluate changes in peripapillary choroidal thickness in patients with branch retinal vein occlusion (BRVO) over 12 months, using spectral-domain optical coherence tomography with enhanced depth imaging.

METHODS

This retrospective, interventional case series included 20 treatment-naive patients with unilateral BRVO with at least 12 months follow-up. The peripapillary choroidal thickness was measured over 12 months.

RESULTS

In BRVO-affected eyes, the mean peripapillary choroidal thickness was 213.5 ± 51.7 μm (126.1[FIGURE DASH]326.9 μm) at baseline and 129.6 ± 39.3 μm (65.9[FIGURE DASH]197.1 μm) at 12 months. In nonaffected contralateral eyes, the mean peripapillary choroidal thickness was 194.1 ± 39.8 μm (158.5[FIGURE DASH]238.3 μm) at baseline and 156.6 ± 56.2 μm (125.9[FIGURE DASH]213.9 μm) at 12 months. The mean peripapillary choroidal thickness decreased significantly over 12 months in both BRVO-affected and nonaffected eyes (P < 0.001, both eyes). Although the mean peripapillary choroidal thickness was not significantly different between groups at baseline (P = 0.472), it was significantly lower in BRVO-affected eyes than in nonaffected eyes at 12 months (P = 0.036).

CONCLUSION

Peripapillary choroidal thickness decreased significantly over 12 months in BRVO-affected eyes and nonaffected eyes in patients with unilateral BRVO.

SAFETY OF INTRAVITREAL DEXAMETHASONE IMPLANT (OZURDEX): The SAFODEX study. Incidence and Risk Factors of Ocular Hypertension

PURPOSE

To analyze the incidence, risk factors, and time course of intraocular pressure elevation after intravitreal dexamethasone implant (Ozurdex).

METHODS

The medical charts of 421 consecutive eyes (361 patients) receiving one or more Ozurdex implant between October 2010 and February 2015 were reviewed retrospectively. Ocular hypertension was defined as intraocular pressure of at least 25 mmHg or an increase of at least 10 mmHg from baseline. The main indications for treatment were retinal vein occlusion (34%), diabetic macular edema (30%), postsurgical macular edema (17%), uveitis (14%), and other etiologies (5%).

RESULTS

Among 1,000 intravitreal injections, ocular hypertension was recorded for 28.5% of injected eyes over a mean follow-up period of 16.8 months (3-55). Intraocular pressure-lowering medication was required for 31% of eyes. Only three eyes with preexisting glaucoma required filtering surgery to manage postinjection intraocular pressure elevation. Early retreatment between the third and fourth month does not increase the risk of intraocular pressure elevation. Younger age, male sex, Type 1 diabetes, preexisting glaucoma treated with dual or triple therapy, and a history of retinal vein occlusion or uveitis were significant risk factors for ocular hypertension after dexamethasone implant injection (P < 0.05 for all the above).

CONCLUSION

Episodes of ocular hypertension after Ozurdex implant were generally transient and successfully managed with topical treatment. An analysis of the risk factors may help to determine the risk-benefit ratio for individual patients treated with dexamethasone implants.

Retinal Vein Occlusion Review

Retinal vein occlusions are a very common condition with great importance in ophthalmology clinical practice. This article reviews the salient epidemiology, risk factors, clinical features, and treatments related to retinal vein occlusions.