Case of Unilateral Peripheral Cone Dysfunction

Abstract

Purpose: Peripheral cone dystrophy is a subgroup of cone dystrophy, and only 4 cases have been reported. We present a patient with unilateral peripheral cone dysfunction and report the functional changes determined by electrophysiological tests and ultrastructural changes determined by spectral domain optical coherence tomography (SD-OCT). Case: A 34-year-old woman complained of blurred vision in both eyes. Our examination showed that her visual acuity was 0.05 OD and 0.2 OS. A relative afferent pupillary defect was present in her right eye. The results of slit-lamp examination, ophthalmoscopy, and fluorescein angiography were normal except for pallor of the right optic disc. SD-OCT showed a diffuse thinning of the retina in the posterior pole of the right eye. A severe constriction of the visual fields was found in both eyes but more in the right eye. The photopic full-field electroretinograms (ERGs) were reduced in the right eye but normal in the left eye. The multifocal ERGs were severely reduced throughout the visual field except in the central area of the right eye. The multifocal ERGs from the left eye were normal. The pattern visual evoked responses were within the normal range in both eyes. She had a 5-year history of sniffing paint thinner. Results: Although the visual dysfunction was initially suspected to be due to psychological problems from the results of subjective tests, objective tests indicated a peripheral cone dysfunction in the right eye. The pathophysiological mechanism and the relationship with thinner sniffing were not determined. Conclusions: Our findings indicate that peripheral cone dysfunction can occur unilaterally. Electrophysiology and SD-OCT are valuable tests to perform to determine the pathogenesis of unusual ocular findings objectively.

Optical Coherence Tomography Findings in Unilateral Peripheral Cone Dysfunction Syndrome: A Case Report

“…Five cases of unilateral cone dystrophy have been reported [12][13][14][15], but the current case is not in the same category because of the residual foveal bulge. Previous studies have reported the electrophysiologic and clinicopathological findings in peripheral cone dystrophy [1][2][3][4][5][6][7]. The ff-ERG of peripheral cone 6 dystrophy shows attenuation or disappearance of the cone response similar to typical cone dystrophy [1,[4][5][6][7].…”

“…Kondo et al first determined the pathogenesis of peripheral cone dystrophy using electrophysiology [1]. Thereafter, some cases of peripheral cone dysfunction syndrome and peripheral cone dystrophy have been reported that were analyzed by electroretinography (ERG) and optical coherence tomography (OCT) [2][3][4][5][6][7]. However, in those reports the pathological analyses had been performed using spectral-domain OCT (SD-OCT).…”

Optical Coherence Tomography Findings in Unilateral Peripheral Cone Dysfunction Syndrome: A Case Report

“…Previous studies have reported the electrophysiologic and clinicopathological findings in peripheral cone dystrophy [1][2][3][4][5][6][7]. The ff-ERG of peripheral cone dystrophy shows attenuation or disappearance of the cone response similar to typical cone dystrophy [1,[4][5][6][7].…”

Multimodal imaging of a case of peripheral cone dystrophy

“…They concluded that the signs and symptoms of these patients were not manifested at an early stage in the more common type of PCD [ 4 ]. Mochizuki et al [ 5 ] presented a 34-year-old patient with unilateral peripheral cone dysfunction.…”