Buphthalmos

Abstract: Glaucoma is a leading cause of blindness, afflicting more than 60 million people worldwide. Increased intraocular pressure (IOP) due to impaired aqueous humor drainage is a major risk factor for the development of glaucoma. Here, we demonstrated that genetic disruption of the angiopoietin/TIE2 (ANGPT/TIE2) signaling pathway results in high IOP, buphthalmos, and classic features of glaucoma, including retinal ganglion degeneration and vision loss. Eyes from mice with induced deletion of Angpt1 and Angpt2 (A1A2FloxWB mice) lacked drainage pathways in the corneal limbus, including Schlemm’s canal and lymphatic capillaries, which share expression of the PROX1, VEGFR3, and FOXC family of transcription factors. VEGFR3 and FOXCs have been linked to lymphatic disorders in patients, and FOXC1 has been linked to glaucoma. In contrast to blood endothelium, in which ANGPT2 is an antagonist of ANGPT1, we have shown that both ligands cooperate to regulate TIE2 in the lymphatic network of the eye. While A1A2FloxWB mice developed high IOP and glaucoma, expression of ANGPT1 or ANGPT2 alone was sufficient for ocular drainage. Furthermore, we demonstrated that loss of FOXC2 from lymphatics results in TIE2 downregulation, suggesting a mechanism for ocular defects in patients with FOXC mutations. These data reveal a pathogenetic and molecular basis for glaucoma and demonstrate the importance of angiopoietin ligand cooperation in the lymphatic endothelium.

Abstract: Importance The ocular manifestations and sequelae of Zika virus infection are not well known. Recently, the World Health Organization changed the declaration of Zika as a public health emergency and designated the viral outbreak and related microcephaly clusters as a long-term program of work. This change indicates the urgent need to evaluate and document ophthalmic manifestations in patients for timely management of this disease. In addition, confirmation whether the public health problem in Brazil extends to other regions in South America is needed. Objective To report the ocular manifestations of congenital Zika syndrome with microcephaly in Colombia and Venezuela. Design, Setting, and Participants This prospective case series included 43 patients from 2 ophthalmic centers in Colombia and Venezuela who underwent evaluation from October 1, 2015, through June 30, 2016, and were clinically diagnosed with congenital Zika syndrome. Twenty patients were Hispanic; 13, African; 8, white; and 2, Native American. Interventions Ophthalmic and systemic evaluations and serologic testing were performed on all infants. Patients underwent external ocular examination and dilated ophthalmoscopy. Serologic testing ruled out toxoplasmosis, rubella, cytomegalovirus, syphilis, and human immunodeficiency virus. Main Outcomes and Measures Ophthalmic manifestations of congenital Zika syndrome. Results Of the 43 patients included in this series (28 female and 15 male), the mean (SD) age at examination was 2.1 (1.5) months. The mothers of all the children had no ophthalmic findings and did not report ocular symptoms during pregnancy. All patients had bilateral ophthalmic manifestations. Optic nerve findings included hypoplasia with the double-ring sign, pallor, and increased cup-disc ratio in 5 patients (11.6%). Macular abnormalities included mild to severe pigment mottling in 27 patients (63%) and lacunar maculopathy in 3 (6.9%). Chorioretinal scarring was present in 3 patients (7%). Eleven patients (26%) had a combination of lesions in the posterior pole. Five patients (12%) were diagnosed with congenital glaucoma, characterized by the clinical triad of epiphora, photophobia, and blepharospasm; increased intraocular pressure; corneal clouding at birth; and buphthalmos. These data reveal that 12% (95% CI, 5%-24%) of cases of congenital Zika with microcephaly had anterior segment abnormalities and 88% (95% CI, 76%-94%) had important macular and optic nerve abnormalities. The visual sequelae of these ophthalmic manifestations remain unknown. Conclusions and Relevance Congenital Zika syndrome in the current study had severe ocular abnormalities, and all patients had bilateral involvement. Ocular findings were focal macular pigment mottling, chorioretinal atrophy with a predilection for the macular area, congenital glaucoma and optical nerve hypoplasia, and optic disc abnormalities. Ophthalmic examination is recommended in patients with congenital Zika syndrome.