Purpose: To report a case of pseudo-unilateral occult macular dystrophy (OMD) with an Arg45Trp mutation in the RP1L1 gene and had unilateral functional changes for about 9 years.
Case report: A 64-year-old woman with a decimal visual acuity of 1.0 in both eyes complained about difficulties with visual tasks because of presbyopia. At the age of 65 years, her visual acuity in the left eye decreased to 0.2, while that in the right eye was 0.7. The fundus of both eyes was normal except for drusen. After 10 years and at the age of 75 years, her visual acuity in the right eye decreased to 0.3. Focal macular electroretinograms (ERGs) at this time were severely attenuated in both eyes, while the full-field ERGs were within normal limits. Ophthalmoscopy showed that the fundus of both eyes was still normal. Genetic analysis revealed a heterozygous mutation, Arg45Trp, in the RP1L1 gene.
Conclusions: These findings indicate that the phenotype in some cases of OMD with an Arg45Trp mutation in the RP1L1 gene can be unilateral for a considerable period.