Evaluating the impact of quadrant switch onintraocular pressure changes in intraviteral aflibercept and ranibizumabinjections

Diabetic retinopathy (DR) is one of the most common causes of preventable vision loss that can occur between the ages of 20-65. One of the leading causes of vision loss in DR is diabetic macular edema (DME). Increased vascular permeability is the cause of DME. This is known to be associated with increased vascular endothelial growth factor (VEGF) level. In developed countries, age-related macular degeneration (AMD) is the most common cause of irreversible visual loss at advanced age. AMD can be divided into two types: wet and dry type. Although the wet type is less common, it is considered to be more aggressive compared to the dry type. Choroidal neovascularization (CNV) formation is characteristic lesion of the wet type AMD. The formation of CNV is mainly due to an increased VEGF load. Intravitreal injections of intravitreal aflibercept and ranibizumab might cause complications like elevation of intraocular pressure (IOP), endophthalmitis, retinal tear, retinal detachment and vitreous hemorrhage. In the literature, much attention has been paid for the sudden increase on IOP following intravitreal injection. However, less is known about the impact of quadrant change on IOP in recurrent intaviteral anti-VEGF injections patients. In the current study, 123 eyes, who were under DR and AMD treatment, were evaluated. IOP and VR levels were measured in patients, who were injected from the superotemporal quadrant, at least ten times. For the next injection of the same eye, instead of using the same quadrant, IOP and vitreus reflux (VR) were measured after an injection was performed from an inferotemporal quadrant that was never used before. The results suggested a significant association between VR and IOP change (p<0,001). viii The amount of VR following an injection from the inferotemporal quadrant was higher compared to the superotemporal quadrant. Correspondingly, IOP was also significantly different between the two quadrants. In conclusion, the traumatic effects of recurrent injections at the same quadrant caused structural changes in conjunctiva and sclera. As a result, the VR became restricted and this might lead to an increased IOP. Key Words: Aflibercept, Diabetic retinopathy, Intraocular pressure, Ranibizumab, Recurrent intraviteral injection, Vitreus reflux, Wet type ageassociated macular degeneration.