Evaluation of intracameral injection of ranibizumab and bevacizumab on the corneal endothelium by scanning electron microscopy

Long-term dynamic changes and influencing factors of corneal morphology after multiple intravitreal injections of anti-VEGF drugs

To observe alterations in corneal morphology caused by repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF). Prospective cohort study. Seventy-seven eyes were treated with intravitreal injection of anti-VEGF from June 2021 to March 2023. There were 25 eyes of neovascular age-related macular degeneration (nAMD), 24 eyes of diabetic macular edema (DME), and 28 eyes of retinal vein occlusion (RVO). Aflibercept was used in 37 eyes and Ranibizumab was used in 40 eyes. 3 + PRN was used. Corneal endothelium and corneal thickness were measured using a corneal endothelial microscope. The data related to central corneal thickness, corneal endothelial cell density (ECD), average cell size, coefficient of variation (CV), proportion of hexagonal cells (Hex%) was collected. A comparison was also made between baseline and the dynamic changes of all indexes 1 year following the last injection. It was observed that in comparison to baseline, ECD and Hex% decreased significantly after the 3rd injection of Aflibercept and Ranibizumab. However, ECD did not decrease further and remained at the same level as after the last injection. Hex% and average cell size increased to a certain extent in comparison to the last injection. All the changes were found to be statistically significant (P < .01). After 3 injections, ECD in DME group was markedly lower than that in nAMD and RVO group, but the CV in DME group was higher than that in nAMD as well as RVO groups, and all the differences were statistically significant (P < .05). Following intravitreal anti-VEGF therapy, DME is more likely than other disorders to result in a decrease in ECD. Repeated intravitreal injections of anti-VEGF drugs can reduce the Hex% and ECD to a certain extent. After the last injection, Hex% can progressively recover, and ECD can remain stable without further declining. After injections, ECD in DME group was found to be significantly lower than that in nAMD and RVO groups, but CV in DME group was significantly higher in comparison to the other 2 groups. In patients with macular edema, repeated intravitreal injections of anti-VEGF may have certain effects on corneal morphology. Patients with diabetes mellitus in particular should pay special attention to corneal safety following repeated intravitreal injections if they have significantly reduced ECD at baseline.

Effect of Intravitreal Aflibercept on Corneal Endothelial Cells

AIM

To determine the effect of repeated intravitreal injections of aflibercept on the corneal endothelium in patients with diabetic macular edema (DME) and macular edema due to retinal vein occlusion (RVO).

METHODS

In a prospective study conducted between January 2021 and November 2023, a total of 87 treatment-naive eyes with DME and RVO were evaluated. The exclusion criteria were surgery or laser intervention during the follow-up period, contact lens wear, cataract surgery in the last 6 months, dystrophy, or other corneal condition that may cause endothelial damage. In addition to routine examinations on the day of application, we also measured the corneal endothelium using specular microscopy on the 1st, 4th and 8th day of injection. We evaluated 4 parameters: endothelial cell density (CD), hexagonality (HEX), coefficient of variability (CV) and central corneal thickness (CCT). First of all, we evaluated the entire cohort of eyes, and then divided it according to 2 criteria; the diagnosis into DME/RVO and according to the lens status into phakic/pseudophakic eyes.

RESULTS

A total of 87 eyes of 68 patients were evaluated. The average age of the patients at the time of diagnosis was 66.8 ±9.3 years. Within the cohort 51 (59%) eyes were phakic and 36 (41%) pseudophakic. A total of 61 (70%) eyes with a diagnosis of DME were treated, and 26 (30%) with RVO. During the follow-up, there were no significant changes in the average values of CD, HEX, CV, CCT due to aflibercept treatment, either in the whole group or in subgroups according to diagnosis or lens condition.

CONCLUSIONS

The results of this study suggest that intravitreal administration of aflibercept in patients with DME and RVO did not have an impact on corneal endothelial parameters, including CCT, HEX, CD and CV. These parameters were measured using endothelial microscopy during an 8-injection observation period.

Effect of Repeated Intravitreal Ranibizumab and Aflibercept Injections on the Cornea in Patients with Age-Related Macular Degeneration

Purpose

To assess the effect of repeated intravitreal ranibizumab injections (RI) and aflibercept injections (AI) on the corneal endothelium and central corneal thickness (CCT) in patients with age-related macular degeneration (AMD).

Materials and Methods

In the retrospective study, 110 eyes of 106 patients, aged 52 to 93 years, were analyzed. Fifty eyes were treated only with RI (I group), and 60 eyes were treated only with AI (II group). Every patient received one intravitreal injection of 0.5 mg of ranibizumab once a month or 2 mg of aflibercept for 3 subsequent months. Each patient received only 3 injections during the whole observation period. Corneal analysis was obtained with the specular microscope. Examinations were performed before initial treatment, after each injection, and 6 months after the first injection. Analysis included corneal endothelial cell density (ECD), hexagonal cell percentage (% Hex), coefficient of variation (CoV), and CCT.

Results

There was a statistically significant ECD loss, regardless of the type of the anti-VEGF agent. The mean ECD value in the I group was 2397 ± 459 cells/mm² before RI, 2389 ± 459 cells/mm² after the first RI, 2386 ± 467 cells/mm² after the second RI, 2378 ± 475 cells/mm² after the third RI, and 2357 ± 460 cells/mm² 6 months after the first RI. The mean ECD value in the II group was 2448 ± 493 cells/mm² before treatment, 2456 ± 498 cells/mm² after the first AI, 2426 ± 496 cells/mm² after the second AI, 2402 ± 488 cells/mm² after the third AI, and 2348 ± 473 cells/mm² 6 months after the first AI. In comparison with the group treated with RI, the group treated with AI presented a greater ECD loss at each measuring point. The percentage of hexagonal cells was decreased in both groups. There was a slight increase in polymegathism in both treated groups. Ranibizumab proved to cause a small increase in CCT, while CCT remained unchanged in the aflibercept group.

Conclusions

Repeated intravitreal injections of 0.5 mg of ranibizumab or 2 mg of aflibercept can influence the morphology of the corneal endothelium but not CCT.

Effect of intravitreal aflibercept on corneal endothelial cells: a 6-month follow-up study

Purpose

To determine the effect of intravitreal aflibercept injection on the corneal endothelium in patients with diabetic or cystoid macular edema caused by retinal vein occlusion.

Material and methods

Forty-six eyes of 44 consecutive patients (27 men, 17 women; age range: 55-88 years) were evaluated. All participants initially received a single intravitreal injection of aflibercept (2 mg in 0.05 mL), followed by pro re nata use and underwent central corneal specular microscopy before the injection and at 1, 3 and 6 months after the first injection during a 6-month follow-up period. The endothelial cell density (ECD), average cell size (AVG), standard deviation of cell size (SD), coefficient of variation of cell size (CoV), maximum of cell size (MAX), minimum of cell size (MIN) and percentage of hexagonal cells (Hex%) were analyzed and the central corneal thickness (CCT) was measured.

Results

No significant differences in the ECD, AVG, SD, CoV, MIN, Hex% and CCT were observed between measurements obtained before and 1, 3 and 6 months after the first injection. However, the MAX measured before injection differed significantly from the values measured at 1, 3 and 6 months after the first injection (P=0.033). An average of 1.43±0.58 intravitreal aflibercept injections were administered per patient.

Conclusion

These study findings indicate that the intravitreal administration of aflibercept (2 mg) might very slightly alter the corneal endothelium within 6 months of the first injection.