Effect of mydriasis on visual field area in retinitis pigmentosa.

PURPOSE: The effect of mydriasis on Goldmann visual field area in patients with retinitis pigmentosa has not been suitably defined. The aim of this study is to determine whether visual field area in these patients varies with pharmacologic mydriasis. METHODS: Fifteen adult patients with retinitis pigmentosa were studied prospectively. Goldmann visual fields with II4e and V4e isopters were obtained in both eyes before and after full pharmacologic mydriasis of the right eye. The isopter areas were quantified and analyzed to determine the effect of mydriasis on visual field area. RESULTS: The difference in the right eye isopter areas was compared with the difference in the left eye isopter areas using paired t tests, where the differences were computed from areas obtained before and after dilation of the right eye. Mydriasis had no significant effect on the visual field in terms of isopter area difference (II4e, P = 0.87; V4e, P = 0.45) and percent change in isopter area (II4e, P = 0.81; V4e, P = 0.24). CONCLUSION: Pharmacologic mydriasis had no appreciable effect on the Goldmann visual field area in a selected group of patients with retinitis pigmentosa. These findings suggest that visual fields of such patients obtained in the dilated or undilated state can be meaningfully compared.     

Normal isopter position in the peripheral visual field in goldmann kinetic perimetry

PURPOSE: Often in young patients the question arises if a disease state has contracted their peripheral boundary of the visual field. Since the 'hill of vision' is steeper in the periphery, kinetic perimetry is more sensitive in detecting peripheral visual field abnormalities than static perimetry. In order to be able with kinetic perimetry to detect mild peripheral visual field constrictions, we determined the normal position of 4 isopters in the peripheral visual field. SUBJECTS AND METHODS: Intraindividual sensitivity variations of the isopters in the peripheral visual field were determined in 3 normal subjects by one perimetrist. Then, in 22 subjects (19-42 years old) the position of the isopters V4e, III4e, I4e and I3e has been determined by one perimetrist. Visual fields were registered using a Goldmann kinetic perimeter. RESULTS: The intraindividual sensitivity variations (measured as 1 standard deviation) for the isopter V4e was 0.98 degrees and for the isopter I4e 1.13 degrees. To visualize the normal isopter positions in the peripheral visual field, the average positions +/- 2 standard deviations were plotted for the isopters V4e, III4e, I4e and I3e. CONCLUSION: In this study, we determined the normal position of 4 isopters frequently used to plot the peripheral visual field. The plots have been printed in a scale of 1:4 in order to facilitate its use. Photocopying the figures on transparencies by scaling them with a factor 4 will allow to superpose the transparencies on individual Goldmann kinetic visual fields in order to easily determine whether the individual isopters are inside or outside the normal range.     

Comparison of central and peripheral visual field properties in the optic neuritis treatment trial

PURPOSE: To compare the results of peripheral kinetic visual field testing and central static perimetry for patients enrolled in the Optic Neuritis Treatment Trial to determine (1) whether loss and recovery of visual field sensitivity in the far periphery was different from that observed in the central visual field and (2) whether the far peripheral visual field provided additional useful information that was not available in the central visual field results. METHODS: Both affected and fellow eyes of 448 patients with optic neuritis in the Optic Neuritis Treatment Trial were evaluated according to the trial protocol during the patients' first 3 years in the study. Central static visual field tests were performed with program 30-2 on the Humphrey Field Analyzer, and peripheral kinetic testing consisted of plotting the I3e and II4e isopters on the Goldmann perimeter. Both test procedures were conducted according to the trial protocols, and quality control assessments and clinical evaluations were performed on all the visual fields. RESULTS: For both affected and fellow eyes at all 11 visits, there was a greater number of abnormal visual fields in the central static perimetry results than in the peripheral kinetic data. Only 2.9% of affected eyes had an abnormal peripheral visual field with a normal Humphrey mean deviation during year 1. At baseline, 97.1% of affected eyes had an abnormal Humphrey mean deviation on central static testing, whereas only 69.9% had abnormal peripheral kinetic visual fields. Approximately 80% of the I3e and II4e isopters for affected eyes that were abnormal at baseline were within normal limits at 30 days, but it took until week 19 for even 70% of the Humphrey mean deviations to return to normal. In addition, the II4e isopters (more peripheral than the I3e isopters) that were abnormal at baseline showed a somewhat greater percentage of improvement from baseline through day 30 than the abnormal I3e isopters. Although this difference is statistically significant, it is probably not clinically significant. For visits after week 19, approximately 25% to 30% of affected eyes had an abnormal Humphrey mean deviation, whereas only 10% to 15% of peripheral kinetic fields were abnormal. CONCLUSIONS: For the affected eye in optic neuritis, the central visual field shows greater abnormalities than the far peripheral visual field. When the results obtained through Humphrey automated central static visual fields and Goldmann peripheral kinetic isopters are compared, the far periphery appears to recover more rapidly and more completely than the central field, at least in more severe cases of optic neuritis. In most cases, recovery in optic neuritis can probably be monitored effectively with automated perimetry of the central visual field alone. However, in cases of severe loss of the central visual field, a peripheral kinetic visual field obtained with a Goldmann perimeter may provide additional information about the patient's vision in the far periphery.     

Visual field assessment and the Austroads driving standard

Purpose: To compare the conventional (Humphrey 24‐2) automated visual field testing with the Goldmann standard visual field test for driving, and to predict how many patients with glaucoma may not meet the Australian driving standard with respect to visual fields. Methods: Four patients (retinitis pigmentosa, glaucoma or vigabatrin treatment) with marked visual field defects as determined by uniocular static computerized perimetry (conventional testing) were re‐evaluated with binocular kinetic Goldmann IV4e target field test (Australian driving standard). A series of 48 consecutive patients seen by the Glaucoma Inheritance Study in Tasmania were assessed with both static computerized perimetry and the Goldmann IV4e target test. Results: The four patients with severe visual field defects (on computerized perimetry) were found to meet the driving standard on the binocular Goldmann IV4e target test. On computerized perimetry, 15 of 48 patients from the Glaucoma Inheritance Study in Tasmania were found to have visual field defects of sufficient severity that they may not meet the driving standard. However, only five of these patients failed the driving standard for visual fields, two of whom were still driving. Conclusions: Patients with severe field defects on conventional uniocular automated perimetry may still meet the Goldmann standard visual field test for driving. Approximately 30% of glaucoma patients would have visual field loss shown on Humphrey 24‐2 test of a severity that requires further testing to determine if they meet the driving standard. Ten per cent of glaucoma patients tested did not meet the driving standard for visual fields.     

A longitudinal study of visual function in carriers of X-linked recessive retinitis pigmentosa

OBJECTIVE: This study was carried out to evaluate the progression of visual function impairment in carriers of X-linked recessive retinitis pigmentosa. We also assessed the relationship between the retinal findings at presentation and the extent of deterioration. DESIGN: Observational, retrospective, case series. PARTICIPANTS: Twenty-seven carriers of X-linked recessive retinitis pigmentosa. METHODS: Each carrier was clinically categorized into one of four grades (grades 0 through 3) depending on the presence or absence of a tapetal-like retinal reflex and the extent of peripheral pigmentary degeneration. A complete ophthalmologic examination was performed and data for visual acuity, visual field area, and electroretinographic measurements were collected on the most recent visit in both eyes. These were then compared with similar data obtained on their initial visits. MAIN OUTCOME MEASURES: A comparison of visual function was carried out between the initial visit and the most recent visit on each carrier. The visual acuity was measured with Snellen's acuity charts. The visual fields to targets V-4-e and II-4-e were planimeterized and used for the analysis. The electroretinographic (ERG) measures used were light-adapted single-flash b-wave amplitudes and 30-Hz red flicker for cone function, dark-adapted maximal b-wave amplitudes, and response to a low intensity blue-flash for rod function. RESULTS: None of the 11 carriers with a tapetal-like reflex only (grade 1) showed any significant change in visual acuity or fields as compared with 3 of 7 (43%) carriers with diffuse peripheral pigmentary findings (grade 3) who showed significant deterioration in visual acuity in at least one eye, and 6 of 7 (86%) who showed a significant decrease in visual field area with at least one target size in at least one eye. By comparison, only 1 of 10 carriers with a grade 1 fundus finding demonstrated a significant decrease in maximal dark-adapted ERG function as compared with 5 of 6 (83%) carriers with grade 3 in response to a single-flash stimulus and with 4 of 5 (80%) carriers in response to a single-flash blue stimulus. For the single-flash photopic response, none of the 10 carriers with grade 1 showed any significant deterioration, whereas 2 of 4 (50%) with grade 3 did show such deterioration. The ERG responses for carriers with grade 2 were in between the extent of decrease in ERG amplitudes of those in carriers with grades 1 and 3. CONCLUSIONS: In our cohort of X-linked retinitis pigmentosa carriers, those with only a tapetal-like retinal reflex at presentation had a better prognosis to retain visual function than those with peripheral retinal pigmentation. These data are useful in counseling such carriers as to their visual prognosis.     

A clinical, psychophysical, and electroretinographic survey of patients with autosomal dominant retinitis pigmentosa.

We have surveyed 104 patients (44 families) with autosomal dominant retinitis pigmentosa. The range of the survey includes clinical history, ocular examination, documentation of genetic history, Goldmann kinetic perimetry with IV/4 and I/4 white targets, two-colour static perimetry, and scotopic and photopic electroretinography. Comparison of interfamilial and intrafamilial patterns in the static perimetry data strongly suggests there may be at least two genetic subgroups within the disease characterised by the pattern of loss of rod function: in subgroup D (13 patients, 4 families) this is diffuse and severe, while in subgroup R (28 patients, 13 families) it is regional. In both D and R loss of cone function is regional, and in R it coincides with loss of rod function. In D patients the rod electroretinogram is absent; in all but two R cases it is present and usually substantial. All D patients were aware of night blindness before the age of 10, but most R patients not until after the age of 20. Many of the patients could not be classified because their disease was so advanced. The effect of disease duration on visual acuity and visual field area is described for all patients.     

A dissociation of thresholds between Goldmann kinetic perimetry and high-pass resolution perimetry in retinitis pigmentosa]

The authors studied the differences between the automated static perimetry of high-pass resolution perimeter (HRP) and the kinetic perimetry of the Goldmann perimeter in 12 patients with retinitis pigmentosa. In a total of 10 eyes of 6 patients, we found 19 quadrants in which the patients were not able to recognize the largest ring target even when the target was within the isopter of the Goldmann perimetry. Also, there were 10 quadrants in which the largest target was not recognized in a total of 6 eyes of 4 patients even though their visual field showed symmetrical isopter in upper and lower or right and left quadrants in the Goldmann perimetry. As a result, it was suggested that the causes of the dissocation were a greater decrease in sensitivity for the low spatial frequency target than the high spatial frequency target and/or a greater decrease in resolution sensitivity than light sensitivity in retinitis pigmentosa.     

Unexplained visual loss

Dominant optic atrophy is the most common heredodegenerative optic neuropathy. Typically, patients present with slowly progressive, bilaterally decreased central visual acuity. Subtle central or cecocentral visual field defect and normal peripheral isopters are demonstrated with perimetry. A defect in blue-yellow discrimination (tritan error axis) is the most common type of dyschromatopsia, however protan and deutan axes may be superimposed. A characteristic optic disk appearance includes temporal disk pallor with excavation. An autosomal dominant inheritance pattern can often be elicited from the family history.     

A comparison of semiautomated versus manual Goldmann kinetic perimetry in patients with visually significant glaucoma

PURPOSE: To determine if semiautomated kinetic perimetry (SKP) is reproducible and comparable to Goldmann manual kinetic perimetry (GVF). METHODS: Glaucoma patients were recruited to perform visual field testing using GVF and SKP. Specific isopters were tested, quantified, and compared. Visual field patterns were analyzed for shape and defect. RESULTS: Ten patients (16 eyes) underwent visual field studies using SKP and GVF, and 8 patients completed a second SKP on a different day. Individual isopter areas were similar between GVF and SKP, although 60% of isopters were larger on SKP by an average of 15%. This was statistically significant for the smaller isopters, I4e (P=0.02) and I2e (P=0.05). Retesting with SKP on a separate day, showed similar isopter areas (P values=0.3 to 1.0), however, the exact location of isopters in degrees from central fixation tended to vary with the smaller test object sizes. Isopter position in degrees from the central axis agreed in at least 3 quadrants in approximately 65% of fields compared. SKP visual field defects and patterns were similar between test strategies. CONCLUSIONS: SKP and GVF testing produce similar visual field results in glaucoma patients, and SKP testing seems to be reliable and reproducible in this population. However, overlapping isopters, typically associated with nonorganic vision loss, and jagged isopters were sometimes observed in SKP visual fields. Further study of SKP is needed to explore these findings.     

Early-onset autosomal dominant retinitis pigmentosa with severe hyperopia

We studied a four-generation family with early-onset autosomal dominant retinitis pigmentosa, severe hyperopia, and axial eye lengths of less than 20 mm. The affected members had decreased vision, night blindness, typical peripheral retinal pigmentary changes, and electroretinographic abnormalities characteristic of retinitis pigmentosa. This pedigree suggests there is another variant of retinitis pigmentosa associated with hyperopia besides Leber's congenital amaurosis and preserved para-arteriole retinal pigment epithelium.     

The application of chromatic dark-adapted kinetic perimetry to retinal diseases

PURPOSE: To demonstrate the value of a 2-color perimetric procedure for determining cone and rod system contributions to the dark-adapted kinetic visual field (VF). DESIGN: Prospective evaluation of perimetric testing procedure. PARTICIPANTS: Five patients with retinal diseases and 6 visually normal individuals. METHODS: Long- and short-wavelength stimuli were presented under dark-adapted conditions in a Goldmann perimeter. Visual fields were measured for the II and V test target sizes with a long-wavelength filter (cut-on at 600 nm) and a short-wavelength filter (cutoff at 510 nm). Light intensities through these filters were matched scotopically for the rod system by producing equal peripheral boundaries on 6 visually normal individuals. To validate the application of this procedure, we tested a patient with congenital achromatopsia and another patient with congenital stationary night blindness (CSNB). We then tested 2 patients with retinitis pigmentosa (RP) and 1 patient with Usher's syndrome to determine the cone and rod contributions to their VF isopters. MAIN OUTCOME MEASURES: Isopters for long- and short-wavelength test stimuli, and the appearance of the test stimuli, whether reported as chromatic or achromatic. RESULTS: The patient with congenital achromatopsia showed superimposed isopters for the 2 stimuli, which were reported as achromatic, demonstrating that the peripheral field boundaries were rod mediated. The patient with CSNB showed an isopter in response to the long-wavelength stimulus that was considerably larger than that in response to the short-wavelength stimulus, both stimuli reported as chromatic, showing that the cone system determined peripheral thresholds for both stimuli. In 2 patients with RP, we observed a mixed pattern of cone or rod system detection of the chromatic stimuli. The peripheral isopters were rod mediated, whereas the cone system determined the central field isopters. In an Usher's syndrome patient, cones mediated both the peripheral and the central field isopters. CONCLUSIONS: A 2-color dark-adapted Goldmann perimetric procedure was able to determine whether the VF isopters were rod or cone mediated in 5 patients with various forms of retinal disease.     

The visual field of pseudophakic patients. Perimetric and statistical study

One hundred and twenty two visual fields were studied in 98 pseudophakic subjects, using cinetic perimetry according to Goldmann, in order to plot the internal (I1), medium (I2) and peripheral (I4) isopters. Computerized processing of data provided average results, allowing the following conclusions: In general, 20% of the total surface is lost in pseudophakia. This loss, as a consequence of prismatic effects of lenses, involves the internal isopters (26%) rather than the peripheral isopters (15%). Individually, these data can be modified by the location of the lens or by the diameter of its optical part: the more anterior or the smaller is the optical part, the narrower does the visual field become. Additional correction, particularly if exceeding 2 diopters is a supplementary factor of reduction. The perimetric consequences of pseudophakia are functionally latent. Nevertheless, the prismatic effects of intraocular lenses could account for the difficulties met in examination of peripheral fundus.     

Retinitis pigmentosa in a man's right eye and corneal opacity, corneoiridal adhesion, and normal retina in the left eye

A 45-year-old-man, the product of a first-cousin relationship, complained of night blindness. His right eye has signs of early-stage retinitis pigmentosa. His left eye, which had suffered a corneal infection in childhood, had poor visual acuity, corneal opacity, corneoiridal adhesion, normal retina, and a normal electroretinographic response. The retinitis pigmentosa is likely an autosomal recessive trait, and the retinal lesion in the left eye may have been delayed by light deprivation produced by the corneal abnormalities.     

视网膜色素变性的实验研究进展

视网膜色素变性是一种遗传性眼病,遗传方式包括常染色体显性遗传、常染色体隐性遗传及性连锁隐性遗传等,目前已知的突变位点超过3 000个,造成本病临床治疗困难。眼科学者致力于探索视网膜色素变性的治疗方式,进行了大量实验研究,主要有药物治疗、细胞移植、基因治疗等治疗方式。药物治疗包括中药、抗氧化剂、抗凋亡剂、神经营养因子等,与其它治疗方式相比,无侵入性,且方便价廉,但其作用机制尚需更深入的研究。细胞移植被认为是治疗视网膜色素变性的有效方法,但有可能引起视网膜前膜及黄斑皱褶。基因治疗虽然存在一定的局限性,但随着基因编辑技术和新型基因递送载体的发展,未来会成为视网膜色素变性最有希望的治疗方式之一。本文对近年来视网膜色素变性的实验研究进行了综述与展望。     

Disease course of patients with X-linked retinitis pigmentosa due to RPGR gene mutations

PURPOSE: To measure the rates of visual acuity, visual field, and ERG loss in patients with X-linked retinitis pigmentosa due to RPGR mutations and to determine whether these rates differ from those of patients with dominant retinitis pigmentosa due to RHO mutations. METHODS: Snellen visual acuities, Goldmann visual field areas (V4e white test light), and 30 Hz (cone) full-field ERG amplitudes were recorded for an average of 9.8 years in 113 patients with RPGR mutations. After censoring data to eliminate ceiling and floor effects, we used longitudinal regression to estimate mean rates of change and to compare these rates with those of a previously studied cohort of 134 patients with dominant retinitis pigmentosa due to RHO mutations, who were followed for an average of 8.9 years. Survival analysis was used to compare the age distribution of legal blindness in these two groups. To explain group differences in visual acuity, optical coherence tomograms were recorded in some patients to visualize central retinal structure. RESULTS: Mean annual exponential rates of decline for the patients with RPGR mutations were 4.0% for visual acuity, 4.7% for visual field area, and 7.1% for ERG amplitude. Each of these rates was significantly different from zero (P < 0.001). The rates of visual acuity and visual field loss were significantly faster than the corresponding rates in the RHO patients (1.6%, P < 0.001 and 2.9%, P = 0.002, respectively), whereas the rate of ERG amplitude loss was comparable to that in the RHO patients (7.7%, P = 0.39). The median age of legal blindness was 32 years younger in the RPGR patients than in the RHO patients, due primarily to loss of visual acuity rather than to loss of visual field. Loss of acuity in RPGR patients appeared to be associated with foveal thinning. CONCLUSIONS: Patients with X-linked retinitis pigmentosa due to RPGR mutations lose visual acuity and visual field more rapidly than do patients with dominant retinitis pigmentosa due to RHO mutations.     

A survey of hereditary aspects of pigmentary retinal dystrophies

A study of 707 cases of retinitis pigmentosa and choroideraemia presenting over 12 years were classified according to their modes of inheritance-439 autosomal recessive (62%), 193 autosomal dominant (27%), 75 X-linked (10.7%). The patients with autosomal recessive transmission included 58 Usher syndrome, 12 Laurence-Moon-Bardet-Biedl syndrome and 33 Leber's congenital amaurosis. Another 37 had an early onset with macular degeneration and 31 were of late onset with pericentral dystrophy. Forty two were offspring of consanguineous parents. Of 193 individuals (78 families) with autosomal dominant inheritance, 20% had night blindness from early childhood. With X-linked transmission, 33 males and 31 female carriers comprised the retinitis pigmentosa group and eight males and three carrier females, choroideraemia. Almost all this X-linked group were of British ancestry. Of patients originating from the Mediterranean area, 94% had autosomal recessive disease.     

A survey of hereditary aspects of pigmentary retinal dystrophies

A study of 707 cases of retinitis pigmentosa and choroideraemia presenting over 12 years were classified according to their modes of inheritance--439 autosomal recessive (62%), 193 autosomal dominant (27%), 75 X-linked (10.7%). The patients with autosomal recessive transmission included 58 Usher syndrome, 12 Laurence-Moon-Bardet-Biedl syndrome and 33 Leber's congenital amaurosis. Another 37 had an early onset with macular degeneration and 31 were of late onset with pericentral dystrophy. Forty two were offspring of consanguineous parents. Of 193 individuals (78 families) with autosomal dominant inheritance, 20% had night blindness from early childhood. With X-linked transmission, 33 males and 31 female carriers comprised the retinitis pigmentosa group and eight males and three carrier females, choroideraemia. Almost all this X-linked group were of British ancestry. Of patients originating from the Mediterranean area, 94% had autosomal recessive disease.     

Autosomal recessive retinitis pigmentosa is associated with mutations in RP1 in three consanguineous Pakistani families

PURPOSE: To localize and identify the gene and mutations causing autosomal recessive retinitis pigmentosa in three consanguineous Pakistani families. METHODS: Blood samples were collected and DNA was extracted. A genome-wide scan was performed by using 382 polymorphic microsatellite markers on genomic DNA from affected and unaffected family members, and lod scores were calculated. RESULTS: A genome-wide scan of 25 families gave an hlod = 4.53 with D8S260. Retinitis pigmentosa in all three families mapped to a 14.21-cM (21.19-Mb) region on chromosome 8 at q11, flanked by D8S532 and D8S260. This region harbors RP1, which is known to cause autosomal dominant retinitis pigmentosa. Sequencing of the coding exons of RP1 showed mutations in all three families: two single-base deletions, c.4703delA and c.5400delA, resulting in a frame shift, and a 4-bp insertion, c.1606insTGAA, all causing premature termination of the protein. All affected individuals in these families are homozygous for the mutations. Parents and siblings heterozygous for the mutant allele did not show any signs or symptoms of RP. CONCLUSIONS: These results provide strong evidence that mutations in RP1 can result in recessive as well as dominant retinitis pigmentosa. The findings suggest that truncation of RP1 before the BIF motif or within the terminal portion results in a simple loss of RP1 function, producing a recessive inheritance pattern. In contrast, disruption of RP1 within or immediately after the BIF domain may result in a protein with a deleterious effect and hence a dominant inheritance pattern.     

Different amino acid substitutions at the same position in rhodopsin lead to distinct phenotypes

PURPOSE: Identification of a novel rhodopsin mutation in a family with retinitis pigmentosa and comparison of the clinical phenotype to a known mutation at the same amino acid position. METHODS: Screening for mutations in rhodopsin was performed in 78 patients with retinitis pigmentosa. All exons and flanking intronic regions were amplified by PCR, sequenced, and compared to the reference sequence derived from the National Center for Biotechnology Information (NCBI, Bethesda, MD) database. Patients were characterized clinically according to the results of best corrected visual acuity testing (BCVA), slit lamp examination (SLE), funduscopy, Goldmann perimetry (GP), dark adaptometry (DA), and electroretinography (ERG). Structural analyses of the rhodopsin protein were performed with the Swiss-Pdb Viewer program available on-line (http://www.expasy.org.spdvbv/ provided in the public domain by Swiss Institute of Bioinformatics, Geneva, Switzerland). RESULTS: A novel rhodopsin mutation (Gly90Val) was identified in a Swiss family of three generations. The pedigree indicated autosomal dominant inheritance. No additional mutation was found in this family in other autosomal dominant genes. The BCVA of affected family members ranged from 20/25 to 20/20. Fundus examination showed fine pigment mottling in patients of the third generation and well-defined bone spicules in patients of the second generation. GP showed concentric constriction. DA demonstrated monophasic cone adaptation only. ERG revealed severely reduced rod and cone signals. The clinical picture is compatible with retinitis pigmentosa. A previously reported amino acid substitution at the same position in rhodopsin leads to a phenotype resembling night blindness in mutation carriers, whereas patients reported in the current study showed the classic retinitis pigmentosa phenotype. The effect of different amino acid substitutions on the three-dimensional structure of rhodopsin was analyzed by homology modeling. Distinct distortions of position 90 (shifts in amino acids 112 and 113) and additional hydrogen bonds were found. CONCLUSIONS: Different amino acid substitutions at position 90 of rhodopsin can lead to night blindness or retinitis pigmentosa. The data suggest that the property of the substituted amino acid distinguishes between the phenotypes.     

Multicenter genetic study of retinitis pigmentosa in Japan: I. Genetic heterogeneity in typical retinitis pigmentosa

A nationwide, multicenter study of typical retinitis pigmentosa (RP) was carried out in collaboration with 18 hospitals throughout Japan to obtain current information for genetic counseling. We analyzed the genetic heterogeneity of RP based on the parental consanguinity of 434 probands registered during a 6-month period in 1990. A gradual decline in the frequency of consanguineous marriage was recognized among the normal parents of RP patients. The relative frequencies of inheritance patterns were estimated as: autosomal recessive, 25.2%; autosomal dominant, 16.9%; X-linked, 1.6%; and simplex, 56.3%. A comparison of these results with previous reports in Japan revealed a decline in the relative frequency of autosomal recessive cases and an increase in simplex cases. This suggests a decrease in the incidence of autosomal recessive retinitis pigmentosa in Japan, as well as the necessity for exhaustive investigations aimed at identifying inheritance patterns for RP patients seeking genetic counseling.