Field-dependent aniseikonia associated with an epiretinal membrane a case study
Gerard C de Wit1, Cecilia S Muraki
1Optical Diagnostics, Culemborg, The Netherlands.
Ophthalmology
|December 14, 2005
Summary
Field-dependent aniseikonia, caused by retinal conditions like epiretinal membranes, can vary with visual field angle. This contrasts with optically induced aniseikonia and presents challenges for conventional optical correction.
Area of Science:
- Ophthalmology
- Neuroscience
- Vision Science
Background:
- Aniseikonia, a disparity in perceived image size/shape between eyes, is typically assumed constant with visual field angle (VFA).
- This assumption holds for optically induced aniseikonia, often linked to anisometropia or pseudophakia.
Observation:
- A case report details a patient with a unilateral epiretinal membrane experiencing aniseikonia.
- Aniseikonia measurements varied significantly with VFA, decreasing as VFA increased from 0.36 to 5.7 degrees.
Findings:
- Retinal-origin aniseikonia, such as that caused by an epiretinal membrane, can be field-dependent, unlike optically induced aniseikonia.
- The patient's aniseikonia ranged from 23% to 2.5% across different VFAs, a pattern not observed in a control subject.
Implications:
- Field-dependent aniseikonia poses challenges for correction with conventional optics, which assume constant magnification.
- Partial correction of field-dependent aniseikonia improved visual comfort, particularly for reading tasks.
