Foveal structure and visual function in nanophthalmos and posterior microphthalmos

Area of Science:

• Ophthalmology
• Retinal Imaging
• Human Physiology

Background:

• Nanophthalmos and posterior microphthalmos cause visual impairment, but the underlying reasons are not fully understood.
• Foveal structure alterations are observed in these conditions, impacting visual acuity.

Purpose of the Study:

• To investigate foveal structure in nanophthalmos and posterior microphthalmos.
• To determine the impact of demographic, clinical, and imaging parameters on best-corrected visual acuity (BCVA).

Main Methods:

• Cross-sectional case-control study including 33 patients and 114 healthy controls.
• High-resolution retinal imaging (OCT) and foveal retinal layer thickness measurements.
• Mixed-effect model for structure-function correlations and BCVA prediction.

Main Results:

• Most patients (28/33) exhibited altered foveal structure with loss of the foveal avascular zone and impaired BCVA.
• Consistent findings included outer nuclear layer widening, elongated photoreceptor outer segments, and normal macular pigment distribution.
• Choroidal effusion significantly impacted BCVA; age, refractive error, axial length, and foveal retinal thickness explained 61.7% of BCVA variability.

Conclusions:

• Choroidal effusion, age, refractive error, axial length, and retinal layer thickness are key determinants of BCVA variability and foveal heterogeneity in nanophthalmos and posterior microphthalmos.
• Findings offer insights into foveal development and emmetropization.
• Results aid clinicians in assessing these conditions.