Comparison between "early" or "late" intravitreal injection of dexamethasone implant in branch (BRVO) or central (CRVO) retinal vein occlusion: six-months follow-up

Risk factors in central retinal vein occlusion: A multi-center case-control study conducted on the Italian population : Demographic, environmental, systemic, and ocular factors that increase the risk for major thrombotic events in the retinal venous system

PURPOSE

To explore the risk factors for central retinal vein occlusion (CRVO) by comparing a large sample of patients with healthy controls.

MATERIALS AND METHODS

Multi-center case-control study. The study group includes patients affected by central retinal vein occlusion, confirmed angiographically, aged 50 years old or above (Group A). The control group includes healthy subjects without an history of retinal vein occlusion (Group B). Outcome measures: age, gender, active smoking, presence of uncontrolled arterial hypertension (uHTN), presence of the following comorbidities: diabetes mellitus type II (DMII), chronic liver disease (CLD), chronic kidney disease (CKD), thyroid disease (TD), systemic lupus erythematosus (SLE), hyperhomocystenemia (HHcy), dyslipidemia (DLip), carotid artery disease (CAD), glaucoma, atrial fibrillation (AF), migraine headache (MH), chronic obstructive pulmonary disease (COPD), obstructive sleep apnea syndrome (OSAS), history of myocardial infarction (MI). Odds-ratios were calculated with logistic regression analysis.

RESULTS

A total of 203 patients (Group A) and 339 controls (Group B). Statistically-significant differences were found for the following variables: age (OR: 1.109 [1.081-1.138], p < .001), active smoking (OR: 2.048 [1.210- 3.466], p < .008), DMII (OR: 4.533 [2.097-9.803], p < .001), HHcy (OR: 4.507 [2.477-10.001 ], p < .001), DLip (OR: 2.255 [1.352-3.762], p  =  .002), CAD (OR: 6.632 [2.944- 14.942], p < .001), glaucoma (OR: 4.656 [2.031-10.673], < .001), OSAS (OR: 1.744 [1.023-2.975], < .041), uHTN (OR: 3.656 [2.247-5.949], < .001). No statistically-significant differences were found for the other variables.

CONCLUSIONS

Older age, active smoking, as well as presence of DMII, HHcy, DLip, CAD, glaucoma, OSAS, and uHTN, all increase the risk for CRVO. A comprehensive assessment of patients with CRVO is paramount. Adequate control of all the aforementioned risk factors is likely of great significance in reducing the incidence of CRVO among the general population, and it likely plays an important role in improving the prognosis following the occlusive event.

Fatty acid-binding protein 4 is an independent factor in the pathogenesis of retinal vein occlusion

The main objective of current study was to identify the fatty acid-binding protein 4 (FABP4) expressed in both adipocytes and macrophages in vitreous fluid from patients with retinal vein occlusion (RVO). Patients with RVO (n = 14, CRVO; central RVO n = 5, BRVO; branch RVO n = 9) and non-RVO (macular hole or epiretinal membrane, n = 18) were surgically treated by a 25 or 27G vitrectomy. Undiluted vitreous fluid samples obtained as the result of surgery were subjected to enzyme-linked immunosorbent assays to measure the levels of FABP4 and vascular endothelial growth factor A (VEGFA).Data including ocular blood flow by laser speckle flow graphy (LSFG), height and weight, systemic blood pressures and several blood biochemistry values were collected. Among the LSFG mean blur rate (MBR) values of the optic nerve head (ONH) at baseline, MA (MBR of all area), MV (MBR of the vascular area), and MV-MT (MBR of the tissue area) were significantly decreased in patients with CRVO. The levels of V-FABP4 and V-VEGFA were relatively or significantly (P< 0.05) higher in the BRVO or CRVO patients compared to the non-RVO patients, respectively. A positive correlation (r = 0.36, P = 0.045) or a negative correlation (r = -0.51, P = 0.006) was observed between Log V-FABP4 and Log V-VEGF, or Log V-FABP4 and MV-MT at post-operative 1-week, respectively. Furthermore, neither of these factors were affected with respect to sex, body mass index and several clinical parameters that were collected, except that a positive correlation was observed for Log V-FABP4 with blood urea nitrogen. Stepwise multivariable regression analyses indicated that MV-MT at post-operative 1week was independently associated with Log V-FABP4 after adjustment for age and gender, and gender and Log V-FABP4 were independently associated with Log V-VEGFA after adjustment for age. The findings reported herein suggest that an independent factor, FABP4 may be synergistically involved in the pathogenesis of RVO with VEGFA.

Effects of Repeated Intravitreal Injections of Dexamethasone Implants on Intraocular Pressure: A 4-Year Study

Purpose

Dexamethasone and other corticosteroids are administered intravitreally to treat a variety of retinal diseases. As a side effect, they can alter intraocular pressure (IOP). The purpose of this study is to describe the incidence, severity, and management of ocular hypertension following the administration of multiple intravitreal injections of dexamethasone implants.

Materials and Methods

A total of 78 eyes of 78 subjects (males 62%; females 38%; mean age 67 ± 13 years SD) received a total of 152 intravitreal injections of 0.7 mg dexamethasone implants over 4 years. Indications included retinal vein occlusion (87%), diabetic macular edema (9%), wet-type age-related macular degeneration (4%). Ocular hypertension was defined as intraocular pressure above 23 mmHg or any pressure increase of 10 mmHg or more from baseline values. IOP was measured by applanation tonometry before the injection (T0), as well as one week (T1), one month (T2), and three months (T3) afterwards.

Results

Five percent (4/78) of subjects developed ocular hypertension after the 1st injection. On the second and third rounds, additional 7.2% (3/42) and 4.2% (1/24) of subjects developed the same side effect. Among the 8 subjects who received a fourth injection, none was found with OHT. Pressure elevations were detected at T2 and T3. In all patients, topical medical therapy was sufficient to lower the IOP below threshold. Mean pressure variations following the first injection as compared to previous recorded values were +0.97 mmHg (T1), +0.92 mmHg (T2), and -0.41 mmHg (T3) (p < 0.05). Mean pressure variations following the second injection were +0.54 mmHg (T1), +0.23 mmHg (T2) and -0.66 mmHg (T3) (p < 0.05).

Conclusion

Ocular hypertension is a recognized side effect of intravitreal dexamethasone. Some patients develop it right after the first injection, while others develop it subsequently, on the 2nd or 3rd round. This side effect becomes most apparent 30-90 days following the implantation procedure and responds well to topical pressure-lowering medications.