Assessing the risk of retinitis pigmentosa with age-of-onset data.

Early characteristic electrophysiologic and ophthalmoscopic changes may help predict the development of retinitis pigmentosa. Until recently, if these were absent or equivocal, the ophthalmologist had to rely on the family pattern of transmission and simple Mendelian genetic methods to calculate the patient's risk of manifesting the disease. We used data on age of onset of subjective night blindness in 229 patients with retinitis pigmentosa (189 with autosomal recessive disease, 27 with autosomal dominant disease, and 13 with X-chromosome-linked disease) with Bayesian methods of probability calculation to predict the risk of retinitis pigmentosa development in a given patient more accurately than is possible with simple Mendelian methods. The risk for one subject used as an example was reduced from 50% to 12.9%.

Possible assignment of a dominant retinitis pigmentosa gene to chromosome 1.

A genetic linkage study, performed on a large family with autosomal dominant retinitis pigmentosa (RP), demonstrated that the RP gene may be linked to the Rh locus, known to be on the short arm of human chromosome 1. Linkage studies on RP along with other studies, can help to more accurately classify these disease entities. Localizing the RP gene locus has the potential for allowing the early diagnosis of individuals at risk.

HLA typing in retinitis pigmentosa.

HLA serological typing was performed on 173 patients with retinitis pigmentosa (RP) of all hereditary types. No significant difference was found in the frequency of any HLA (A, B, C) antigen, when comparing autosomal dominant and recessive RP patients with a control population.

Progressive nature of pigmented paravenous retinochoroidal atrophy.

A 30-year-old man with pigmented paravenous chorioretinal atrophy showed, within a relatively short time, changes that documented the progressive nature of this disease. These changes included: further constriction of peripheral visual fields; more extensive and frequently confluent areas of retinochoroidal atrophy; a scalloped appearance of lesions resembling posterior gyrate atrophy; peripheral pigment clumping; and the presence of localized atrophic areas with crystal deposition in the peripheral retina.

Anticipatory guidance in elective ophthalmic surgery.

With respect to the preoperative ophthalmic patient, anticipatory guidance is a technique of informing the patient in a detailed way about all aspects of the upcoming intervention, including the need for surgery, the degree of pain and disability to be expected, type of anesthesia to be used, some information about the postoperative course, and the expected disability following surgery on either a temporary or a permanent basis. The purpose of anticipatory guidance is to permit the patient to make a better psychologic adaptation to a crisis situation and to relieve preoperative anxiety through information, resulting in easier postoperative recovery. In addition, anticipatory guidance and improved understanding between physician and patient may go far to reduce those misunderstandings that lead to malpractice actions subsequent to surgical procedures.

Probable genetic linkage between autosomal dominant retinitis pigmentosa (RP) and amylase (AMY2): evidence of an RP locus on chromosome 1.

A linkage analysis is reported for three branches of a single family segregating for autosomal dominant retinitis pigmentosa. A statistically significant lod score of 3.9 is obtained for the RP locus and AMY2 at a recombination frequency of 1%. This linkage indicates that the RP locus is on the no. 1 chromosome since the AMY2 locus has been placed on the short arm of 1. Lod scores are reported for four other loci on chromosome 1; none of these achieve statistical significance. Analyses are reported for 23 additional autosomal markers and close linkage with RP can be excluded for a number of these.

The clinical significance of retinitis pigmentosa without pigment: a computer assisted analysis.

Sixty-eight consecutive patients with retinitis pigmentosa were studied to determine the frequency of the non-pigmented form of the disease. There was an overall incidence of 22%. Fifty percent of all cases had no characteristic pigmentation, if the duration of night vision difficulty was three years or less. The study lends statistical support to the concept that the non-pigmented form of retinitis pigmentosa is frequently an early stage of the disease and not an unusual or atypical variant. Patient without the pigmentary changes characteristic of the disorder also showed less functional impairment: the ERG b-wave was more apt to be recordable, although impaired; and the rod threshold, as determined by dark adaptation measurement, was less elevated. The clinician should suspect retinitis pigmentosa, even in the absence of pigmentary changes, if there is a family history of the disorder, night blindness, peripheral field loss, and an impaired or non-recordable electroretinographic response.

Retinitis pigmentosa: accelerated course of visual loss secondary to exogenous thyroid administration.

A 30 year old white female with known retinitis pigmentosa of autosomal dominant transmission was placed on thyroid medication for weight control purposes for nearly one year. The unusually rapid progression of visual field changes and the increased severity of night vision problems are documented by serial functional studies.

Unilateral retinitis pigmentosa sine pigmento.

A patient presented with unilateral findings of night blindness shown by impaired rod function and dark adaptation, constricted visual fields with good central acuity, a barely recordable electro-retinographic b-wave, and a unilaterally impaired electro-oculogram. There were none of the pigmentary changes usually associated with retinitis pigmentosa. The unaffected right eye was normal in all respects. Therefore the case is most probably one of unilateral retinitis pigmentosa sine pigmento.

Retinitis pigmentosa without pigment.

Sixty-eight consecutive patients with retinitis pigmentosa were studied to determine the frequency of the nonpigmented form of the disease. There was an overall incidence of 22%. Fifty percent of all cases had no characteristic pigmentation, if the duration of night vision difficulty was three years or less. The nonpigmented form of retinitis pigmentosa was frequently an early stage of the disease and not an unusual or atypical variant. Patients without the pigmentary changes characteristic of the disorder also showed less functional impairment: the electroretinographic b wave was more apt to be recordable, although impaired, and the rod threshold, as determined by dark adaptation measurement, was less elevated. The clinician should suspect retinitis pigmentosa, even in the absence of pigmentary changes, if there is a family history of the disorder, night blindness, peripheral field loss, and an impaired or nonrecordable electroretinographic response.

Pigmented paravenous retinochorodial atrophy.

Three male patients had paravenous pigmented retinochoroidal atrophy. Extensive retinal function tests showed characteristic retinal pigment epithelial abnormalities on fluorescein angiography, loss of peripheral visual field, diminution of the electroretinographic b-wave, and elevated rod threshold on dark adaptometry. The disease appears to be more progressive than previously indicated, and in late stages, may cause legal blindness through involvement of the posterior pole. No treatment is known.