ABSTRACT
Fovea plana is a congenital condition characterized by anatomic absence of the foveal pit. It may be isolated or associated with congenital ocular anomalies. In this report, we present a case of fovea plana associated with situs inversus of the optic disc, optic disc hypoplasia, tilted optic disc, and prepapillary vascular loop and with best corrected visual acuity of 20/32. The aim of this report is to demonstrate the coexistence of very rare multiple optic disc anomalies and fovea plana, and also to emphasize that the use of multimodal imaging methods facilitates the identification of rare anomalies.
Introduction
Fovea plana, previously called foveal hypoplasia, is a condition characterized by the anatomic absence of the foveal pit. It may be isolated or associated with diseases such as albinism, microphthalmia, and achromatopsia. Fovea plana is usually bilateral, and visual acuity varies depending on accompanying pathologies.1 It has been reported that fovea plana may affect 3% of children, even those with normal visual acuity.2
Situs inversus of the optic disc is a rare congenital anomaly characterized by the abnormal course of vessels emerging from the optic disc.3,4 It may be associated with tilted optic disc and optic disc hypoplasia.5 In this report, we present a case of fovea plana associated with multiple optic disc anomalies consisting of situs inversus of the optic disc, optic disc hypoplasia, tilted optic disc, and prepapillary vascular loop, with multimodal imaging findings.
Discussion
Situs inversus of the optic disc is a congenital embryonic anomaly characterized by blood vessels initially emerging nasally from the optic disc before turning sharply temporally. It is believed to occur as a result of anomalous insertion of the optic stalk into the optic vesicle and dysversion of the optic disc. It can be associated with other optic disc pathologies, primarily tilted optic disc.3,4,5 It is reported to affect 5% of the normal population.6
As the use of OCT became common in daily practice, we gained a better understanding of the anatomic changes that take place in patients with fovea plana. Continuation of the inner retinal layers through the fovea result in increased central foveal thickness and absence of the foveal pit is in OCT cross-sections.7 In OCTA studies of fovea plana patients, it has been reported that no foveal avascular zone is evident in the superficial or deep capillary plexus.8 Fovea plana may be associated with conditions such as albinism, aniridia, retinopathy of prematurity, achromatopsia, microphthalmia, myopia, and incontinentia pigmenti.1 There are reports in the literature that patients with optic disc hypoplasia have shallower foveal pit and increased central retinal thickness compared to normal eyes.9 Small optic disc can also be observed in patients with fovea plana associated with albinism and achromatopsy.10 Although these findings suggest a correlation between fovea and optic disc development, the etiopathogenesis of this association is not clear. In our case, fovea plana was observed with optic disc hypoplasia as well as findings of situs inversus, tilted disc, and prepapillary vascular loop. With this report, we aimed to draw attention to a very rare case of fovea plana with largely preserved visual acuity despite the coexistence of multiple optic disc anomalies. We also aimed to emphasize that the use of multimodal imaging methods facilitates the identification of rare anomalies.
