====== Foveal Hypoplasia ======

  * Lack of formation of the foveal depression
    * Foveal plana = absent foveal pit
  * associated with poor vision and nystagmus

==== Ocular Associations ====
  * Aniridia (PAX6)
  * Achromatopsia
  * Congenital retinal macrovessel
  * Coloboma 
  * Optic Nerve Hypoplasia
  * Retinopathy of Prematurity

==== Isolated Foveal Hypoplasia ====
  * Autosomal Dominant from PAX 6 gene variants
  * Autosomal Recessive from SLC38A8 gene variants
    * SLC38A8 codes for a glutamine transporter in photoreceptors, mutations in the 6th transmembrane domain cause underdevelopment of the retina
  * X-linked from FRMD7 gene variants
    * FRMD7 regulates neuronal outgrowth 
    * also associated with familial infantile nystagmus 

==== Systemic Associations ====
  * [[albinism|Albinism]]
  * [[fevr|Familial Exudative Vitreoretinopathy]]
  * [[incontientia_pigmenti|Incontientia pigmenti]]
  * Prematurity
  * Stickler Syndrome

==== Diagnostic Procedures ====
  * Visual acuity
    * VA is variable but can range from 20/40 to 20/200
  * Oculomotor
    * Nystagmus and strabismus
  * Ophthalmoscopy
    * absence of foveal reflex and foveal avascular zone and typical macular pigment
  * [[optical_coherence_tomography|OCT]]
    * Absence of foveal pit, persistent inner retinal layers through fovea 
    * Example of an OCT report of a child with foveal hypoplasia
{{::foveal_hypoplasia.png}}

  * OCT-A
    * absence of superficial capillary plexus and variable decrease in deep capillary plexus in the fovea

==== References ====
  * [[https://www.sciencedirect.com/science/article/pii/S0161642019322122?via%3Dihub|Study of the Leicester Grading system, Rufai et al 2020]]
    * Rufai SR, Thomas MG, Purohit R, Bunce C, Lee H, Proudlock FA, Gottlob I. Can Structural Grading of Foveal Hypoplasia Predict Future Vision in Infantile Nystagmus?: A Longitudinal Study. Ophthalmology. 2020 Apr;127(4):492-500. doi: 10.1016/j.ophtha.2019.10.037. Epub 2019 Nov 4. PMID: 31937464; PMCID: PMC7105819
  * {{ :histologic_development_of_the_human_fovea_from_midgestation_to_maturity.pdf |Hendrickson A, Possin D, Vajzovic L, Toth CA. Histological development of the human fovea from midgestation to maturity. Am J Ophthalmol 2012;154:767-778.e2.}}