A dominant Stargardt's macular dystrophy locus maps to chromosome 13q34.

OBJECTIVE: To identify the chromosomal location of a mutated gene that causes an autosomal dominant Stargardt's macular dystrophy. METHODS: Ocular examinations were performed on 67 members of a large kindred to identify those with macular dystrophy. DNA analyses defined the genotype of all family members at 49 polymorphic loci. Linkage between the gene defect responsible for this macular dystrophy and each polymorphic locus was assessed by lodscore calculations. RESULTS: Diminished visual acuity and funduscopic abnormalities were found in 29 family members, which was diagnostic of macular dystrophy. Genetic analyses demonstrated that polymorphic loci from chromosome 13 band q34 were linked to the gene defect in this family. Haplotype analyses localized the disease locus to an 8-centimorgan interval between loci D13S159 and D13S158/D13S174. CONCLUSION: A disease locus responsible for an autosomal dominant Stargardt's macular dystrophy is located on chromosome 13 band q34. Identification of the mutated gene at this locus will lead to a better understanding of macular degeneration.

Determining the convergence demand for a patient who reads at a close working distance.

Low vision practitioners frequently prescribe microscopic spectacles for reading. Although the lens power enables the patient to focus clearly, the convergence demand at the close working distance may make it difficult for the patient to achieve and sustain binocular vision. Base-in prism and lens decentration can reduce the convergence demand but even these methods are not always sufficient to achieve the goal of binocular vision. A means of calculating the convergence demand for a patient who is using microscopic spectacles of known parameters is presented as an aid to understanding the dynamics involved in achieving binocularity.

Dominant inheritance of Stargardt's disease.

Ten members of an extended family have come to the Indiana University (IU) Optometry Clinic in Indianapolis for low vision services. All 10 individuals had lost vision as the result of a juvenile onset hereditary macular degeneration. The funds appearance consisted of an atrophic macular degeneration surrounded by the characteristic yellowish flecks of Stargardt's disease. A study of the family tree revealed a clearly dominant mode of inheritance, whereas Stargardt's disease has traditionally been considered a recessive trait. We are presenting this family study as an unusual instance of dominant inheritance of Stargardt's disease.

Stargardt's disease: a review of the literature.

In 1909, Dr. Stargardt described seven patients who developed a juvenile onset macular degeneration with a striking presentation of yellowish flecks surrounding the macula. The eponym "Stargardt's disease" has since been used to describe this condition. However, there is some ambiguity in the literature concerning the characteristics which differentiate this condition from other hereditary retinal dystrophies. We have undertaken a review of the literature in an attempt to clarify the parameters of Stargardt's disease.

CPF-550 vs. C-Lite: a comparison study.

We conducted a two-part study to evaluate patient satisfaction with the Corning CPF-550 lenses and to determine whether or not the success of these lenses can be attributed to their selective attenuation of the short wave-lengths of light. In the first part of our investigation we asked nine low vision patients who were currently wearing CPF-550 lenses to evaluate the performance of the tint. Their responses were generally very favorable. In the second part of the study, seven of those patients were given identical prescriptions made of C-Lite material with a solid gray tint on the back surface and a photo-gray extra front surface. They were asked to compare the two filters. To our surprise, six of the seven preferred the more neutral density C-Lite lenses over the CPF-550 filter. Although we have been encouraged by the results of the first part of the study to continue prescribing the CPF-550 lenses, the second part of the study has caused us to question the theory behind the success of these lenses and has alerted us to the fact that some individuals may be even more satisfied with a neutral gray photochromic tint.