Abstract
Purpose:
To describe the relationship between the retinal pigment epithelium (RPE) and ocular development in the bestrophinopathies. The bestrophinopathies are a group of three diseases in which the pathogenic defect is located at the level of the RPE: Best vitelliform macular dystrophy (BVMD), autosomal dominant vitreoretinochoroidopathy (ADVIRC) and autosomal recessive bestrophinopathy (ARB).
Methods:
Thirty patients with BVMD, 15 patients with ADVIRC and 8 patients with ARB, with proven BEST1 mutations, underwent a detailed ophthalmological examination, including measurement of axial length and corneal diameter. In addition, psychophysical and electrophysiological testing (ISCEV-standard ERG, PERG and EOG) was performed in the majority of cases.
Results:
With a mean value of 21.8mm, the axial length is significantly shorter in both BVMD and ARB, than the normal mean value of 23.6mm. In ADVIRC patients, ocular length showed a mean value of 23.4mm, a difference that was not statistically significant. In ADVIRC, the corneal diameter is reduced with a mean value of 9.7mm. In BVMD and ARB with a mean value of respectively 10.7mm and 11.2mm, microcornea is less pronounced. Visual field defects were limited to (peri)central defects in addition to enlarged blind spots in all ADVIRC patients, and (peri)central sensitivity loss in ARB patients. Full-field flash ERGs were normal in 10/10 eyes with BVMD, abnormal in 24/30 eyes in ADVIRC and 12/16 eyes in ARB. A Lp/Dt-ratio < 150% on EOG was seen in 48/60 eyes with BVMD, and all patients with ADVIRC and ARB.
Conclusions:
These results show that ocular development is abnormal in the bestrophinopathies and thus suggest that either the presence of an abnormal bestrophin protein, or the complete absence of it in the RPE, influences ocular development. The normal axial length in ADVIRC is rather unexpected since the disease has been associated with ocular developmental problems. In BVMD and ARB, the axial length is significantly shortened. Microcornea is seen in all three conditions, but is more pronounced in ADVIRC.
Keywords: 539 genetics •
497 development •
701 retinal pigment epithelium