R. J. McLean

Mutations in FRMD7, a newly identified member of the FERM family, cause X-linked idiopathic congenital nystagmus.

Idiopathic congenital nystagmus is characterized by involuntary, periodic, predominantly horizontal oscillations of both eyes. We identified 22 mutations in FRMD7 in 26 families with X-linked idiopathic congenital nystagmus. Screening of 42 singleton cases of idiopathic congenital nystagmus (28 male, 14 females) yielded three mutations (7%). We found restricted expression of FRMD7 in human embryonic brain and developing neural retina, suggesting a specific role in the control of eye movement and gaze stability.

Early signs of longitudinal progressive cone photoreceptor degeneration in achromatopsia.

Aims To characterise longitudinal progressive retinal changes in achromatopsia. Methods Ultrahigh-resolution spectral optical coherence tomography (Copernicus, 3 μm axial resolution) was used to obtain tomograms of the fovea from five children and three adults with achromatopsia. Each patient was scanned twice with a mean follow-up time of 16 months. Progressive changes in reflectivity at the inner segment/outer segment (IS/OS) junction, the central macular and outer nuclear layer thickness were analysed. Results Younger patients (<10 years; patient 1–5) showed progressive morphological changes at the IS/OS junction between visits 1 and 2. However, older patients (>40 years; patients 6–8) did not have any changes in the retinal morphology between visits 1 and 2. In patients 1 and 2, IS/OS discontinuities (visit 1) developed into a hyper-reflective zone confined to the fovea (visit 2). In patient 3, the hyper-reflective zone (visit 1) progressed to form an IS/OS disruption and early formation of a small hypo-reflective zone (visit 2). Patients 4 and 5 had a hypo-reflective zone (visit 1) which subsequently increased in size (visit 2). There was a decrease in central macular and outer nuclear layer thickness between visits 1 and 2 in children. Conclusions For the first time, we show progressive longitudinal changes in retinal morphology in achromatopsia. Early changes include subtle IS/OS reflectivity alterations. The dynamic retinal changes in younger patients provide evidence that it represents a progressive disorder, and implementation of gene therapy during the early stages of the disease may provide best prognosis.

The pharmacological treatment of nystagmus: a review

Nystagmus is an involuntary, to-and-fro movement of the eyes that can result in a reduction in visual acuity and oscillopsia. Mechanisms that cause nystagmus are better understood in some forms, such as acquired periodic alternating nystagmus, than in others, for example acquired pendular nystagmus, for which there is limited knowledge. Effective pharmacological treatment exists to reduce nystagmus, particularly in acquired nystagmus and, more recently, infantile nystagmus. However, as there are very few randomized controlled trials in the area, most pharmacological treatment options in nystagmus remain empirical.

Vertical optokinetic nystagmus in Parkinson's disease.

Parkinsons disease (PD) is associated with a number of oculomotor deficits; however, little is known about changes in vertical optokinetic nystagmus (OKN) associated with PD. We recorded eye movements in 14 PD patients and 14 age‐matched controls in response to large field OKN stimulation using stimulus velocities of 20°/second and 40°/second. We compared asymmetry of horizontal and vertical responses in the two groups. We found vertical OKN to be strongly asymmetric in PD with reduced gains for downward‐moving stimuli. This asymmetry was significantly greater than that recorded in control volunteers. We postulate that this could result from an abnormal pursuit/early OKN system in PD leading to greater influence of the delayed OKN system.

The pharmacological treatment of nystagmus: a review.

Nystagmus is an involuntary, to-and-fro movement of the eyes that can result in a reduction in visual acuity and oscillopsia. Mechanisms that cause nystagmus are better understood in some forms, such as acquired periodic alternating nystagmus, than in others, for example acquired pendular nystagmus, for which there is limited knowledge. Effective pharmacological treatment exists to reduce nystagmus, particularly in acquired nystagmus and, more recently, infantile nystagmus. However, as there are very few randomized controlled trials in the area, most pharmacological treatment options in nystagmus remain empirical.