Three separate investigations are reported, covering a total of 795 patients from different parts of Finland, two of them consisting of inmates of old people's homes in two towns (N=205 and 262) and one a randomly selected population from Q rural commune (N = 328). They show the mean prevalence of exfoliation syndrome (PS) to be 14.2 Vo in age group 60 <69 years, 21.9 Vo in age group 70-79 and 34.7 Yo in age group 2 80. The prevalence increases statistically significantly with age. The mean prevalence of PS in all three groups was 22.4 Vo. No isolate-like accumulation of PS could be demonstrated. The figures seem representative of the hole country.

Multipoint linkage analysis of choroideremia (TCD) and seven X chromosomal restriction fragment length polymorphisms (RFLPs) was carried out in 18 Finnish TCD families. The data place TCD distal to PGK and DXS72, very close to DXYS1 and DXYS5 (Zmax = 24 at theta = 0) and proximal to DXYS4 and DXYS12. This agrees with the data obtained from other linkage studies and from physical mapping. All the TCD males and carrier females studied have the same DXYS1 allele in coupling with TCD. In Northeastern Finland, 66/69 chromosomes carrying TCD had the same haplotype at loci DXS72, DXYS1, DXYS4, and DXYS12. The same haplotype is seen in only 15/99 chromosomes not carrying TCD. Moreover, in 71/104 non-TCD chromosomes, the haplotype at six marker loci is different from those seen in any of the 76 TCD chromosomes. This supports the previously described hypothesis that the large Northern Finnish choroideremia pedigrees, comprising a total of over 80 living patients representing more than a fifth of all TCD patients described worldwide, carry the same mutation. These linkage and haplotype data provide improved opportunities for prenatal diagnosis based on RFLP studies.

Ninety-two cases of granular corneal dystrophy, most of them belonging to 5 pedigrees are described. The age of manifestation in this Finnish type of granular dystrophy is first in the end of the second decade, and visual acuity is in mean normal through the whole life. An autopsy study showed no changes outside cornea elsewhere in the eyeball. In one family with granular dystrophy, another type of dystrophy, hereditary fleck dystrophy of the cornea, was accidentally found.

The purpose of the paper is to describe results of combined use of argon laser photocoagulation and cryotherapy in the treatment of stage 3+ retinopathy of prematurity in a non-controlled clinical series of 6 premature children with a birth weight of 545-1610 g (mean 914 g) and a gestational age of 24-31 weeks. Both treatment modalities were performed in the same session, and in 5 cases both eyes were treated. Inactivation of the proliferative process was obtained with one treatment session in 3 cases, with two treatment sessions in 3 cases. No serious late sequelae of retinopathy of prematurity developed in any of the eyes, one eye has an ectopic macula and esotropia, and one child has high myopia (-8.0 D) and exotropia. Laser treatment is less irritating and the scars are less pronounced compared with cryocoagulation, but in some cases treatment of the most anterior retina with laser is difficult. Combination of the two treatment modalities may in these cases give the best result.

Linkage studies using restriction fragment length polymorphisms were conducted in the X‐linked disorder, choroideremia, designated TCD for Progressive Tapeto‐Choroidal Dystrophy. Previously demonstrated close linkage with locus DXYS1 was confirmed (lod 11.44 at 0 recombination distance). In addition, locus DXYS12 was found to be closely linked with TCD (lod 3.31 at 0 recombination distance). The disease mainly occurs in three large kindreds in remote Northern Finland. While formal genealogical proof is lacking, all presently living (more than 80 affected males and 120 carrier females) probably originate from a common founder couple born in 1644 and 1646, twelve generations ago. All 36 patients and 48 carriers tested from the three kindreds had the same haplotype (TCD/DXYS1, llkb/DXYS12,1.6kb). Given that at least 105 female meioses transmitting TCD have occurred since 1650 in these kindreds, extremely close linkage between TCD, DXYS1 and DXYS12 is suggested. The above haplotype is a very useful diagnostic tool in these TCD families. We suggest that our historical‐genealogical approach to linkage analysis may be possible elsewhere in similar isolated populations.