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Idiopathic infantile nystagmus (IIN) consists of involuntary oscillations of the eyes. The familial form is most commonly X-linked. We recently found mutations in a novel gene FRMD7 (Xq26.2), which provided an opportunity to investigate a genetically defined and homogeneous group of patients with nystagmus. We compared clinical features and eye movement recordings of 90 subjects with mutation in the gene ( FRMD7 group) to 48 subjects without mutations but with clinical IIN (non- FRMD7 group). Fifty-eight female obligate carriers of the mutation were also investigated. The median visual acuity (VA) was 0.2 logMAR (Snellen equivalent 6/9) in both groups and most patients had good stereopsis. The prevalence of strabismus was also similar ( FRMD7 : 7.8%, non- FRMD7 : 10%). The presence of anomalous head posture (AHP) was significantly higher in the non- FRMD7 group ( P < 0.0001). The amplitude of nystagmus was more strongly dependant on the direction of gaze in the FRMD7 group being lower at primary position ( P < 0.0001), compared to non- FRMD7 group ( P = 0.83). Pendular nystagmus waveforms were also more frequent in the FRMD7 group ( P = 0.003). Fifty-three percent of the obligate female carriers of an FRMD7 mutation were clinically affected. The VA's in affected females were slightly better compared to affected males ( P = 0.014). Subnormal optokinetic responses were found in a subgroup of obligate unaffected carriers, which may be interpreted as a sub-clinical manifestation. FRMD7 is a major cause of X-linked IIN. Most clinical and eye movement characteristics were similar in the FRMD7 group and non- FRMD7 group with most patients having good VA and stereopsis and low incidence of strabismus. Fewer patients in the FRMD7 group had AHPs, their amplitude of nystagmus being lower in primary position. Our findings are helpful in the clinical identification of IIN and genetic counselling of nystagmus patients.

The study investigates the utility of a newly designed mobility test for repeated testing of visual function in patients with severe visual impairment and future application in evaluating functional progress in patients with artificial vision. Ten subjects divided into three groups based on visual acuity (VA) ranging from light perception to 20/200 and reduced visual field (VF) were included in the study. The mobility test consisted of using a set of four different but structurally similar and relatively short mazes having a constant number of obstacles of various sizes. The subjects, divided into three groups by acuity, passed through each course several times. In general, the patients with better VA had a larger extent of VF. Average speed and number of contacts were recorded as measures of performance. The average passing times of the groups through the courses were significantly different (p = 0.03), which was influenced by VA and VF. There was no significant difference in average number of contacts between the groups (p = 0.15). The mobility test proved to be appropriate for gaining statistically relevant results in repeated individual testing of patients with severe vision impairment. Results show promise for use this mobility test as a tool for assessing visual function of patients undergoing implantation of a visual prosthesis for artificial vision.

Background Ocular myasthenia is a localised form of myasthenia clinically involving the extraocular muscles, the m. levator palpebrae superioris and the m. orbicularis oculi. Various symptoms can masquerade peripheral and supranuclear eye muscle palsies and ptosis. Materials and method This literature review of recent years focuses on the diagnostic tests that may be helpful to confirm myasthenia especially in patients without acetylcholine receptor antibodies. Conclusions Ocular dysfunction accounts for 50-80% of the initial manifestation of myasthenia gravis. Clinical manifestations, diagnostic tests and treatment assessment are reviewed. Early recognition of the disease is important for better prognosis.

Diese 1994 an der John-Hopkins-Universitat in Baltimore (USA) in Zusammenarbeit mit der NASA entwickelte tragbare optoelektronische Sehhilfe (Low vision enhancement system = LVES) erweitert bei bis zu lOfacher Vergroserung, gleichzeitiger Kontrastverstarkung und einem 60 mal 40° Gesichtsfeld das Angebot an vergrosernden Sehhilfen. Es wird in 3 Ausfuhrungen (LVES, Gemini und Aurora) angeboten. Wir haben bei 17 jugendlichen Patienten mit unterschiedlicher Sehbehinderung die zentrale Sehscharfe (Ferne und Nahe), das Kontrastsehen (LH) und die Blendempfindlichkeit gepruft und die Ergebnisse mit Brille, bisheriger vergrosernder Sehhilfe und dem LVES miteinander verglichen. Gleichzeitig erfolgte eine ausfuhrliche Befragung uber das subjektive Empfinden. Die Verbesserung der zentralen Sehscharfe betrug im Vergleich zur bestmoglichen Korrektur mit Brille durchschnittlich 7 Visustufen, im Vergleich zum Fernrohrsystem durchschnittlich 2 Visusstufen. Diese Verbesserung wurde den Patienten subjektiv nicht in diesem Ausmas bewust. Auffallend war die Verbesserung des Kontrastsehens und vor allem die verminderte Blendempfindlichkeit durch das allseits abschliesende System. Trotz der objektiv und in unterschiedlichem Ausmas auch subjektiv nachweisbaren Verbesserungen und Vorteile durch das LVES sind die Anwendungsmoglichkeiten begrenzt. Die fehlende Farbdarstellung, das stigmatisierende Ausere, das noch immer hohe Gewicht des Systems und die bei Bewegung deutlichen Scheinbewegungen werden als groste Nachteile angesehen. Nach ausfuhrlicher, zeitintensiver Anpassung wird es aber sicher fur ausgewahlte Patienten, die mit bisherigen Vergroserungssystemen nicht ausreichend versorgt waren, von Nutzen sein. The LVIS (Low vision imaging system), a portable optoelectronic visual aid developed at the John Hopkins University in Baltimore (USA) together with NASA in 1994, broadens the spectrum of available low vision aids. It can enlarge up to a tenfold and simultaneously increase contrast vision and allow for a visual field increase of 60 times 40°. It is available in 3 models (LVES, Gemini, and Aurora). We examined 17 adolescent patients with different degrees of visual impairment for central vision (near and far), contrast acuity (LH), and photosensitivity and compared the results obtained with their eye-glasses, other previous low vision aids and with LVES. At the same time, the patients were extensively asked about their subjective impressions (of the system). The improvement of central visual acuity compared to the best possible correction of eyeglasses was an average of 7 Snellen lines and an average of 2 Snellen lines when compared to a telescopic system. The patients subjectively did not notice the improvement of visual acuity to this extent. The patients did notice an improvement in contrast vision and especially a decrease in photosensitivity due to the closed system. Despite objective and in varying degrees also subjective improvements and advantages of LVES, the usage of this system is limited. The lack of color vision, the stigmatic appearance, the heavy weight, and the appearance of imaginary movements when moving are considered to be the main disadvantages. After an extensive time-consuming adaptation, it will definitely be beneficial for certain patients who have not had satisfactory results with previous enhancement system.

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. Nat Genet

We retrospectively analyzed the ocular findings after polychemotherapy including intrathecal methotrexate, systemic corticosteroids, and prophylactic cranial irradiation in children with acute lymphoblastic leukemia (n = 16) and non-Hodgkin's lymphoma (n = 2). After a median surveillance time of 4.1 years, asymptomatic ocular abnormalities were observed in 83% of the patients: 7/18 had a decreased tear formation, 5/17 had an opacity of the vitreous body, and 13/18 had an opacity of the lens. It was not possible to determine retrospectively which therapy caused a particular effect. A comparison of the 2 irradiation techniques (with and without blocking of the lacrimal glands) showed that in 5/7 children who developed a reduced eye secretion, the lacrimal glands are within the treatment volume. Therefore, the reduced eye secretion is most likely radiation-induced. Whereas the opacities of the vitreous body were caused by thrombopenia and bleeding during the course of disease, corticoid therapy might have contributed to the lens opacities. © 1994 Wiley-Liss, Inc.

Periodic alternating nystagmus consists of involuntary oscillations of the eyes with cyclical changes of nystagmus direction. It can occur during infancy (e.g. idiopathic infantile periodic alternating nystagmus) or later in life. Acquired forms are often associated with cerebellar dysfunction arising due to instability of the optokinetic-vestibular systems. Idiopathic infantile periodic alternating nystagmus can be familial or occur in isolation; however, very little is known about the clinical characteristics, genetic aetiology and neural substrates involved. Five loci (NYS1-5) have been identified for idiopathic infantile nystagmus; three are autosomal (NYS2, NYS3 and NYS4) and two are X-chromosomal (NYS1 and NYS5). We previously identified the FRMD7 gene on chromosome Xq26 (NYS1 locus); mutations of FRMD7 are causative of idiopathic infantile nystagmus influencing neuronal outgrowth and development. It is unclear whether the periodic alternating nystagmus phenotype is linked to NYS1, NYS5 (Xp11.4-p11.3) or a separate locus. From a cohort of 31 X-linked families and 14 singletons (70 patients) with idiopathic infantile nystagmus we identified 10 families and one singleton (21 patients) with periodic alternating nystagmus of which we describe clinical phenotype, genetic aetiology and neural substrates involved. Periodic alternating nystagmus was not detected clinically but only on eye movement recordings. The cycle duration varied from 90 to 280 s. Optokinetic reflex was not detectable horizontally. Mutations of the FRMD7 gene were found in all 10 families and the singleton (including three novel mutations). Periodic alternating nystagmus was predominantly associated with missense mutations within the FERM domain. There was significant sibship clustering of the phenotype although in some families not all affected members had periodic alternating nystagmus. In situ hybridization studies during mid-late human embryonic stages in normal tissue showed restricted FRMD7 expression in neuronal tissue with strong hybridization signals within the afferent arms of the vestibulo-ocular reflex consisting of the otic vesicle, cranial nerve VIII and vestibular ganglia. Similarly within the afferent arm of the optokinetic reflex we showed expression in the developing neural retina and ventricular zone of the optic stalk. Strong FRMD7 expression was seen in rhombomeres 1 to 4, which give rise to the cerebellum and the common integrator site for both these reflexes (vestibular nuclei). Based on the expression and phenotypic data, we hypothesize that periodic alternating nystagmus arises from instability of the optokinetic-vestibular systems. This study shows for the first time that mutations in FRMD7 can cause idiopathic infantile periodic alternating nystagmus and may affect neuronal circuits that have been implicated in acquired forms.

Purpose The Modified Grating Test is a newly designed test for visual acuity (VA) measurement in patients with retinitis pigmentosa (RP) with low vision. Freiburg Visual Acuity Test (FrACT) is a validated test for low vision, but no patients with RP were tested. In our study we tested RP patients investigating the consistency of the Modified Grating Test by comparing the results with those of the FrACT and the ETDRS charts. Methods 16 eyes of 8 patients were tested and divided into 3 groups depending on their VA. Group 1 had a VA of hand motion (HM, n= 6), group 2 counting fingers (CF, n=6) and group 3 better than CF (n=4). The Modified Grating Test consists of a circle with black and white bars of the same width in a decreasing logarithmic order covering the range from 2.7 to 0.3 logMAR. The FrACT is a computerized test with Landoldt C in different directions and in decreasing order. ETDRS charts were used at a distance of 0.5m. Each test was performed 4-5 times. The data were normally distributed. To compare the values we used the paired samples t-test. Results The mean VA in group 1 as measured by the Modified Grating Test was 1.3 logMAR and by FrACT 1.21 logMAR (p=0.21). In the group 2 the patients reached a mean VA of 0.7 logMAR with the Modified Grating Test and 0.6 logMAR with FrACT. 0.68 logMAR was measured with ETDRS charts (p=0.13). Conclusion Our preliminary data suggest that the Modified Grating Test is a suitable test for the low vision range and might be beneficial for the follow up in patients undergoing a retinal prosthesis implantation.