Stromal Dystrophy Research Articles

Recent Advances in Corneal Stromal Dystrophies

Newer biochemical, immunohistochemical, and cell culture techniques have been used to investigate metabolic abnormalities in corneal stromal dystrophies. Organ cultures of macular corneal dystrophy (MCD) have shown a defect in the synthesis of keratan sulphate proteoglycan. Alterations in corneal stromal glycoconjugates have also been detected using biotinylated lectins. An absence of normal keratan sulphate proteoglycan has been shown in the blood of patients with MCD. Granular corneal dystrophy (GCD) is associated with increased phospholipid, as shown by biochemical analysis and staining with Luxol-fast blue. Immunohistochemical stains revealed reactivity with antibodies against microfibrillar protein at the edges of the deposits. Clinically, recently described early features of lattice corneal dystrophy (LCD) include discrete ovoid subepithelial opacities, a diffuse central anterior stromal haze, and anterior stromal dots and filamentary lines. Early clinical recognition of these corneal genetic disorders, with appropriate studies to define their nature and possible pathogenetic mechanisms, are important in expanding our knowledge of this disease spectrum.

Long-term Changes in Corneal Endothelium Following Penetrating Keratoplasty: A Specular Microscopic Study

One hundred clear corneal grafts with a minimum follow-up of 10 years and average follow-up of 17.4 years were studied with specular microscopy. Central and peripheral graft endothelial cell counts as well as central corneal thickness measurements were done and these were correlated with the following parameters: diagnostic subgroups; donor age; graft age (follow-up time); and the postoperative clinical course. The average central endothelial cell counts for the entire series was 684 cells/mm2. Peripheral cell counts were performed in 78 eyes and averaged 749 cells/mm2. Central corneal thickness was measured in 80 eyes and averaged 0.49 mm. There were no statistically significant differences in central or peripheral cell counts when analyzing donor age, graft age, or postoperative course. When cell counts were examined among the diagnostic subgroups, those in the hereditary stromal dystrophy subgroup had a significantly lower cell density when compared to those in the keratoconus subgroup.

CORNEAL TRANSPLANTATION AND HLA HISTOCOMPATIBILITY

A series of 222 cases of 7 mm penetrating corneal grafts were analysed with respect to the influence of HLA compatibility. The degree of compatibility was random as no matching was done (HLA types unknown at time of operation). Consequently, most of the cases showed 3 or 4 incompatibilities. The series was divided into seven diagnostic groups (keratoconus, herpetic keratitis, non-herpetic keratitis, stromal dystrophy, endothelial dystrophy, mechanical lesion and corrosion). In all groups there was a tendency towards better results among the compatible transplantation, but only when considering the entire series could statistical significance be demonstrated. The groups of 0--2 incompatibilities showed fewer rejection episodes or opaque grafts than the groups of 3 or 4 incompatibilities (chi 2 = 9.20, P less than 0.005). Comparing only the frequency of opaque grafts among the two groups the correlation was less significant (chi 2 = 3.66, P similar to 0.05).

EARLY POSTOPERATIVE CHANGES IN GRAFT THICKNESS AFTER PENETRATING KERATOPLASTY: Influence of Host Corneal Disorder on Time Course

In 172 patients the thickness of the corneal graft was followed with frequent measurements during the first 14 days after operation. Three different graft thickness time courses were observed. Patients with keratitis, stromal dystrophy and corrosion or mechanical lesion showed a secondary rise in graft thickness on the 6th postoperative day, while patients with keratoconus and those treated with tranexamic acid showed no rise on the 6th day. Patients with Fuchs' dystrophy differed from the other groups in not reaching the maximal thickness until the 3rd postoperative day. The possible correlation of these three time courses with changes in the fibrinolytic system is discussed.

Results of Penetrating Keratoplasty Over a Four-Year Period

<h2>Summary</h2> A simple random sample of corneal recipients (330) of tissue from a large eye bank was reviewed. The method of review involved the use of hospital surgical reports and patient charts. Reasonably complete information was gathered on 261 cases. The sample covered a four-year time period. Of the total, 59% had a clear cornea one year postoperatively while 41% had less than excellent grafts. Thirty-eight percent of the total enjoyed postoperative visual acuity of better than 20/50 in the eye operated on while 17% had visual acuity of 20/50 or better than 20/200. The remaining 45% had 20/200 or worse. The principal difference between favorable or nonfavorable results was the disease entity. Phakic eyes with keratoconus, stromal dystrophies, and bullous keratopathy had both excellent grafts and excellent vision postoperatively. Reoperated on eyes and poor-prognosis categories had much less favorable results in terms of clarity and vision. Aphakic eyes with bullous keratopathy had clear grafts in 47% of the cases but good vision in only 20% of the sample. No significant relationship was seen between the surgeon and the results—indicating, perhaps, that the surgeons in general are performing surgery within the same range of their capacities as determined by their case selection. There was no significant relationship between the age of the donor tissue and the resultant visual acuity or corneal transparency. The patients in the first sample did not differ significantly according to age, but the more recent sample did show the younger patients achieving better corneal transparency and visual acuity. The longer follow-up of the first sample would not seem to account for that difference.

Congenital Hereditary Stromal Dystrophy of the Cornea

Cornea from patients in two separate pedigrees showing dominant inheritance of a congenital nonprogressvie corneal clouding were examined by light and electron microscopy. The characteristic changes of abnormal corneal lamellae were widely and rather uniformly distributed throughout the stroma. The remaining corneal layers were normal. The findings are consistent with a diagnosis of congenital hereditary stromal dystrophy of the cornea, which differs greatly on both histologic and clinical grounds from the entity known as congenital hereditary endothelial dystrophy of the cornea.

Hereditary crystalline stromal dystrophy of Schnyder. I. Clinical features of a family with hyperlipoproteinaemia.

Hereditary crystalline stromal dystrophy of Schnyder. I. Clinical features of a family with hyperlipoproteinaemia.