On the many faces of Leber hereditary optic neuropathy.

Leber hereditary optic neuropathy (LHON) is a maternally inherited disorder, associated with mutations in the mitochondrial DNA, which is notorious for its aspecific presentations. Two pedigrees are described with cases that are atypical for LHON with respect to sex, age of onset, interval between the eyes becoming affected, course of the disease, concomitant disorders, additional test results, final visual acuity, and/or results of mtDNA analysis. Moreover, the pedigrees themselves did not suggest maternal inheritance. We analysed the diagnostic and clinical genetic difficulties related to the atypical aspects of these pedigrees. We conclude that mtDNA analysis is justified in every case of optic nerve atrophy with no clear cause. Identification of one of the three LHON specifically associated mtDNA mutations is essential to confirm the diagnosis.

Opaque iris claw lens in a phakic eye to correct acquired diplopia.

A 25-year-old man had diplopia caused by abducens nerve paresis on both sides after cranial injury. Because of the patient's reports of persistent diplopia after surgical correction, a specially manufactured, tinted iris claw lens was implanted in the left eye, with the crystalline lens in situ. Fourteen years after surgery, specular microscopy was performed to evaluate the corneal endothelium. The difference in mean endothelial cell density in both eyes was 18.6%. The difference between eyes in polygonality and polymegathism was not significant.

Poly(L-lactide) implants for repair of human orbital floor defects: clinical and magnetic resonance imaging evaluation of long-term results.

PURPOSE: The purpose of this study was to evaluate the long-term outcome of repair of orbital floor defects in patients with resorbable as-polymerized poly(L-lactide) (PLLA) implants and to determine whether these patients showed symptoms that could be indicative of the presence of a late tissue response. PATIENTS AND METHODS: Six patients (four women, two men; mean age, 39 years; range, 18 to 67 years) treated with PLLA implants for orbital floor fractures were recalled for follow-up examination after a period ranging from 3 1/2 to 6 1/2 years. The examination consisted of an interview and a physical examination, including an ophthalmologic and orthoptic consultation. For evaluation of the orbital tissues, coronal spin echo T1- and T2-weighted magnetic resonance images (MRIs) were made through both orbits. RESULTS: None of the patients reported any problems in the years preceding the follow-up examination that might have indicated complications. Clinical examination of the operative sites revealed no abnormalities. At ophthalmologic and orthoptic consultation, normal eye function, without diplopia or restriction of motility, was found in all patients. The MRIs showed no indication of an abnormal or increased soft tissue reaction in the orbital region. CONCLUSIONS: Based on the results of this study, it can be concluded that PLLA orbital floor implants have the potential for successful use in repair of human orbital floor defects.

Chorioretinal dysplasia-microcephaly-mental retardation syndrome: another family with autosomal dominant inheritance.

We describe a boy and his father with the chorioretinal dysplasia-microcephaly-mental retardation syndrome (CDMMS). Our report extends the phenotypic spectrum of autosomal dominant CDMMS by describing microphthalmia for the first time in an autosomal dominant family. The boy was also severely mentally retarded in contrast to the usual mild mental retardation in AD-CDMMS. Furthermore he had hypertonia, dysmorphic features and low body weight, which are uncommon in AD-CDMMS. CDMMS is a rare disorder. We traced 18 reports on CDMMS including 10 families, 6 with horizontal transmission and 4 with vertical transmission. There are 8 reports and observations on isolated cases with CDMMS. This might imply genetic heterogeneity with autosomal recessive and autosomal dominant inheritance, with a more severe clinical picture in the former but with quite variable inter- and intrafamilial expression. A review of the literature is given. The existence of autosomal recessive inheritance in families with so-called horizontal transmission is discussed as variable expression, reduced penetrance and germline mosaicism may also explain this condition. Careful (particularly ophthalmologic) examination of first degree relatives is necessary before genetic counseling is given.

Congenital fibrosis of the extraocular muscles (autosomal dominant congenital external ophthalmoplegia): genetic homogeneity, linkage refinement, and physical mapping on chromosome 12.

Congenital fibrosis of the extraocular muscles (CFEOM) is an autosomal dominant syndrome of congenital external ophthalmoplegia and bilateral ptosis. We previously reported linkage of this disorder in two unrelated families to an 8-cM region near the centromere of human chromosome 12. We now present refinement of linkage in the original two families, linkage analysis of five additional families, and a physical map of the critical region for the CFEOM gene. In each of the seven families the disease gene is linked to the pericentromeric region of chromosome 12. D12S345, D12S59, D12S331, and D12S1048 do not recombine with the disease gene and have combined lod scores of 35.7, 35.6, 16.0, and 31.4, respectively. AFM136xf6 and AFMb320wd9 flank the CFEOM locus, defining a critical region of 3 cM spanning the centromere of chromosome 12. These data support the concept that this may be a genetically homogeneous disorder. We also describe the generation of a YAC contig encompassing the critical region of the CFEOM locus. This interval has been assigned cytogenetically to 12p11.2-q12 and spans the centromere of chromosome 12. These results provide the basis for further molecular analyses of the structure and organization of the CFEOM locus and will help in the identification of candidate genes.

Tapioca melanoma of the iris.

Clinical identification of tapioca melanoma of the iris is important because its medical treatment may differ from that of other malignant iris melanomas. The characteristic iris nodules must be differentiated from granulomatous uveitis, metastases, and Lisch nodules (neurofibromatosis). We will discuss the anterior segment findings, secondary glaucoma, and fluorescein iris angiographic and histopathologic data from two patients, one with a single nodular type and one with a seeding type of tapioca melanoma of the iris.

Late consecutive exodeviations.

A retrospective study was made of the case-histories of 48 patients with late consecutive exodeviations, which had occurred after surgical treatment of a primary convergent squint. An evident predisposition towards the late appearance of the exodeviation could not be demonstrated. In some cases there seemed directly to have been a slight overcorrection, within the limits of operative success. In spite of the attempted overcorrection in a second operation on account of 'exodrift', recurrence of the exodeviation often occurs.

Alternating hyperphoria. Dissociated vertical deviation (DVD) 'occlusion hyperphoria'.

Alternating hyperphoria (synonyms: dissociated vertical deviation (DVD) or occlusion hyperphoria) and variants like 'unilateral patching hyperphoria' ('periodic vertical squint') and monocular vertical nystagmus, which may arise after strabismus operations or loss of the function of one of the eyes, have dynamic properties which differ from those of the vertical vergences or fusional movements in normal binocular vision. Alternating hyperphoria is the result of an early intense disturbance of binocular vision, leading to the absence of vertical fusional vergence or the detection of disparity necessary for this. Vertical disparity vergence is essentially a stabilizing and adaptive system.

Reaction of the rabbit corneal endothelium to nylon sutures. A SEM study.

Nylon and stainless steel sutures separately placed deeply into rabbit corneas by splitting the stroma for a few millimeters, without closing sutures, remained in the cornea for two, four and six weeks respectively. In contrast to the stainless steel sutures an extensive tissue reaction could be observed clinically around the nylon sutures within a few days and was still present after 4-6 weeks. On the endothelial side, covering of the nylon with fibroblast cells took place very slowly, this in contrast with stainless steel. Irritation of the tissue and an oedematous appearance of the endothelium around the nylon suture was the result. At first a kind of collagen network, often mixed with inflammatory cells, was deposited on the nylon material before fibroblast cells could grow in. Covering of the stainless steel started quite soon after implantation, without preliminary deposition of collagen material. The reason for this phenomenon must be sought in the high free surface energy of the stainless steel, which attracts cells, in contrast to nylon which has a very low free surface energy.

Comparison of the reaction of the cornea to nylon and stainless steel sutures: an animal study.

In 11 rabbits a comparison was made between the reactions of the cornea to nylon and to stainless steel sutures, macroscopically and by means of scanning electron-microscopy (SEM). Macroscopically, the wounds sutured with steel thread showed much less reaction than the wounds sutured with nylon. Vascularization was never encountered in the wounds sutured with steel thread. SEM examination also showed clear differences, which became noticeable within a short time. Both on the suture and round the opening in the cornea extensive deposits of material are seen within a short time (1 week) in the case of nylon, in the case of stainless steel this reaction is much less marked. A few weeks later deposits also appear on the steel thread, but these have a different composition and contain no material suggestive of an inflammatory reaction.

Fusional vergence in microstrabismus.

The fusional vergence velocity was studied in microstrabismus and in normal persons. In microstrabismus the system works less precisely in that small changes in disparity produce no response, while it is possible that the difference between the amplitude of the stimulus and the amplitude of the response is greater.

Correlation between NMR scans of extraocular muscles and clinical symptoms in Graves' ophthalmopathy.

In an NMR study of the orbits of patients with Graves' ophthalmopathy a high degree of correlation was found between the severity of the clinical picture and the relative increase in muscular volume in the retrobulbar space.

Congenital absence of conjugate horizontal eye movements.

Loss of conjugate horizontal eye movements is usually due to a lesion in the pons (tumour, vascular, M.S.). However, the condition may also be congenital, either isolated or as part of Moebius's syndrome. Three patients with congenital absence of all conjugate horizontal eye movements are described. In two of them a conjugate pendular nystagmus was observed. Two of the three patients suffered from progressive scoliosis. Congenital absence of all conjugate horizontal eye movements, associated with progressive scoliosis, probably forms a separate clinical entity.

Hereditary congenital external ophthalmoplegia.

Several members of a large pedigree suffering from hereditary congenital external ophthalmoplegia, an autosomal hereditary disorder of ocular movements, were examined and surgically treated. From nystagmographic findings it was concluded that the main cause of this disorder is of supranuclear origin. Specimen of the inferior oblique muscle revealed no abnormalities or showed decrease of type I muscle fibers.

Manifest latent nystagmus of late onset: a case report.

A case of manifest latent nystagmus of late onset in a 13-year-old girl is reported. The nystagmus became manifest during the development of a hypertropia of the left eye. The spontaneous nystagmus was successfully treated by surgical correction of the hypertropia. The observations are discussed with regard to theories on the origin of latent nystagmus.

X-linked incomplete achromatopsia with more than one class of functional cones.

Five affected males in the fifth generation of a large pedigree of X-chromosomal incomplete achromatopsia were tested. All had SWS cone function. A 19-year-old affected man was a classical blue cone monochromat on color matching and spectral sensitivity. A 16-year-old boy showed evidence of a long wavelength sensitive cone active in 8 degrees color matches. With a blue-green background, his cone spectral sensitivity function peaked near 550-560 nm. Three younger boys, aged 7-10 yrs were evaluated only with color matching. All showed evidence of long wavelength cone function with an 8 degree field and one showed long wavelength cones in 2 degree matches. An independent observation concerning the family was the finding that deuteranomaly was introduced in the third generation. The fourth generation women, all obligate carriers of X-linked achromatopsia, had a 0.5 chance to carry deuteranomaly. Neither carrier state per se is usually associated with expression of deuteranomaly. Three of the five tested expressed deuteranomaly. This finding of deuteranomaly in the carrier females might be a consequence of a double carrier state indicating association between the genes for deuteranomaly and X-linked achromatopsia.

Fixation disparity in vertical vergence.

Generally, the vertical vergence response is smaller than the disparity that evokes it, even within the diplopia threshold. However, subjective and objective fixation disparity values obtained with Ogle's device agreed fairly well. The reference lines in themselves appeared to be a stimulus to align the eyes. This finding limits the value of the subjective fixation disparity method when studying the vertical fusional response. Vertical fixation disparity is dependent on time of exposure. Responses of increasing amplitude take longer to reach full amplitude from the position of rest than in the reverse direction.

Fusional movements by peripheral retinal stimulation ('peripheral motor fusion').

Vertical fusional movements elicited by stimulation of the non-foveal retina cannot be distinguished from movements elicited by foveal stimulation, except for a difference in the ratio between the amplitude of the response and the amplitude of the stimulus. This ratio is dependent on target configuration and on the retinal area stimulated. In some circumstances, if the size and richness of contour balances against the object fixated at the fovea, bifoveal fixation can be disrupted. It can be assumed that the stimulus for the motor response is made up of foveal as well as peripheral retinal stimulation. it is plausible that there is a gradient over the retina: the influence of the stimulated retinal area decreases form the fovea towards the periphery.