Cell surface-associated keratan sulfate on normal and migrating corneal endothelium.

PURPOSE: To investigate cell surface-associated keratan sulfate on the corneal endothelium. METHODS: Immunolabeling techniques were used at the light, scanning, and transmission electron microscopic level to localize keratan sulfate on the corneal endothelium. The investigation included human, bovine, and rabbit corneal endothelia. A quantitative study of the relationship between cell size and keratan sulfate levels was conducted on normal bovine corneal endothelium. Changes in the distribution of keratan sulfate and chondroitin sulfate on endothelial cell surfaces were investigated on organ cultured bovine corneas during endothelial wound healing. Changes in the levels of keratan sulfate during endothelial wound healing were investigated in organ cultured human corneas and in vivo in rabbit corneas. Inhibition-enzyme-linked immunosorbent assay also was used to detect keratan sulfate in the aqueous humor. RESULTS: A variegated distribution of keratan sulfate was revealed on normal human, bovine, and rabbit corneal endothelia. Some cells had high levels of keratan sulfate on their surfaces whereas others, sometimes immediately adjacent, had little or none. Wound healing experiments resulted in changes of keratan sulfate levels on the migrating endothelial cells in bovine, human, and rabbit. In wounded organ cultured bovine corneas, there was a decrease in keratan sulfate levels and an increase in chondroitin sulfate levels on migrating endothelial cells. Keratan sulfate was detected in bovine aqueous humor. CONCLUSIONS: The pattern of occurrence of keratan sulfate and chondroitin sulfate on the corneal endothelial cells in normal and wounded cornea suggests that these glycosaminoglycans have differing roles in endothelial adhesion and migration.

Synchrotron x-ray diffraction studies of keratoconus corneal stroma.

The aim of this study was to determine any differences in the collagen molecular and fibrillar packing, or the arrangement of the proteoglycans along the fibril axis, in the stroma of keratoconus and control corneas. High and low-angle x-ray diffraction patterns from the fibrillar and molecular packing of collagen in keratoconus and control corneas were obtained using a synchrotron radiation source. The results indicate no difference in interfibrillar spacing between keratoconus and control corneas at normal physiological hydration, or over a range of hydrations (H = 1-11). This unambiguously demonstrates that the thinning of the stroma that occurs in keratoconus is not a result of closer packing of the collagen fibrils in the stroma. Intermolecular spacings were shown to be significantly (P less than 0.001) lower in keratoconus corneas at normal physiological hydration and over a range of hydrations (H = 1-11). Meridional patterns from the axial distribution of electron density along the collagen fibrils were obtained from untreated control and keratoconus corneas and from the corneas after their proteoglycans were stained with cupromeronic blue. Analysis of the integrated intensities of the first nine orders of these reflections show there is a difference in the staining behavior of collagen-associated proteoglycans in control and keratoconus corneas. Determination of the electron density vectors along the collagen fibrils of cupromeronic blue-stained corneas by the use of Patterson functions indicates that the keratoconus corneal stroma has a specific, ordered proteoglycan that is present in lower numbers along the collagen fibrils, and that it stains less with cupromeronic blue or is in a more disordered arrangement than in the controls.

Ultrastructural and molecular analysis of Bowman's layer corneal dystrophies: an epithelial origin?

PURPOSE: Two mutations (R555Q and R124L) in the BIGH3 gene have been described in anterior or Bowman's layer dystrophies (CDB). The clinical, molecular, and ultrastructural findings of five families with CDB was reviewed to determine whether there is a consistent genotype:phenotype correlation. METHODS: Keratoplasty tissue from each patient was examined by light and electron microscopy (LM and EM). DNA was obtained, and exons 4 and 12 of BIGH3 were analyzed by polymerase chain reaction and single-stranded conformation polymorphism/heteroduplex analysis. Abnormally migrating products were analyzed by direct sequencing. RESULTS: In two families with type I CDB (CDBI), the R124L mutation was defined. There were light and ultrastructural features of superficial granular dystrophy and atypical banding of the "rod-shaped bodies" ultrastructurally. Patients from three families with "honeycomb" dystrophy were found to carry the R555Q mutation and had characteristic features of Bowman's dystrophy type II (CDBII). CONCLUSIONS: There is a strong genotype:phenotype correlation among CBDI (R124L) and CDBII (R555Q). LM and EM findings suggest that epithelial abnormalities may underlie the pathology of both conditions. The findings clarify the confusion over classification of the Bowman's layer dystrophies.

Deposits and proteoglycan changes in primary and recurrent granular dystrophy of the cornea.

OBJECTIVE: To investigate the origin and distribution of granular deposits in the corneas of 3 patients with granular dystrophy, 1 of whom had previously received a lamellar keratoplasty in which the granular dystrophy had recurred. METHOD: Corneal tissue from 2 patients with primary granular dystrophy (patients 1 and 2) and from a patient with recurrent granular dystrophy (patient 3) was examined. Corneal graft tissue was fixed in (1) 3% glutaraldehyde in sodium cacodylate buffer, (2) 2.5.% glutaraldehyde in sodium acetate buffer containing cuprolinic blue, and (3) 4% paraformaldehyde in phosphate-buffered saline. RESULTS: In patient 1 (aged 48 years), electron-dense granular structures were observed in epithelium, Bowman layer, and throughout the stroma. Bowman layer was absent in several places. Patient 2 (aged 78 years) showed similar features except with more deposits in the stroma. In patient 3 (aged 48 years), granular structures were heavily deposited in the epithelium; there were also some deposits in the posterior (host) stroma, some of which were associated with partially degenerated keratocytes. Bowman layer appeared normal. In all 3 patients, the intracellular or extracellular granular structures were surrounded by fine fibrillar material and abnormal proteoglycans. Electron-lucent spaces within the corneal stroma contained large quantities of abnormal proteoglycan filaments that were attached in part to collagen fibrils. CONCLUSIONS: Results from patient 3 support an epithelial origin for the deposits, presumably from keratoepithelin, aggregated with other proteins. The role of keratocytes is less clear, although the presence of deposits in the stroma of all 3 patients, some associated with keratocytes, suggests that these cells might produce granular material in addition to abnormal proteoglycans.

A double blind comparison of guanethidine-and-adrenaline drops with 1% adrenaline alone in chronic simple glaucoma.

We present the results of a double-blind trial comparing the efficacy of a single dose combination of guanethidine 3% and adrenaline 0.5% with that of adrenaline 1% alone in reducing the intraocular pressure of eyes suffering from chronic open-angle glaucoma. The mean fall in ocular tension with the combined therapy was 10.67 mmHg, and with adrenaline 1% 6.31 mmHg, 24 hours after the commencement of phasing. The combined drop produced satisfactory control of ocular tension in all cases. These results indicate that a combined drop of guanethidine 3% and adrenaline 0.5% is a promising topical therapy for the control of chronic open-angle glaucoma.

Syndrome of ischaemic ocular inflammation: six cases and a review.

Patients with carotid occlusive disease may develop a variety of symptoms and signs secondary to chronic ocular ischaemia. We report six cases affecting nine eyes and review the findings of teichopsia, anterior segment ischaemia, venous stasis retinopathy, and ocular neovascularisation. The assessment and surgical management of carotid obstruction are discussed. Some comments on the relevance of coexisting diabetes are made.

Role of sphincterotomy in extracapsular cataract surgery.

Forty patients subjected to extracapsular cataract extraction with posterior chamber intraocular lens implantation in whom a sphincterotomy was required are reported on. This method was used to counter the problems created by a small pupil during surgery. The technique is described and results evaluated.

Endophthalmitis due to caterpillar setae: surgical removal and electron microscopic appearances of the setae.

A case of endophthalmitis due to caterpillar setae was, for the first time, successfully treated by surgical removal of the setae. The procedure was facilitated by the use of sodium hyaluronidate. Scanning and transmission electron microscopy of the setae showed evidence of enzymatic degradation of the shaft and burial of the spines in exudate.

Lectin binding sites in normal, scarred, and lattice dystrophy corneas.

Normal, scarred, and dystrophic corneas were histochemically probed with a panel of 16 lectins by means of an avidin-biotin revealing system. Normal corneal epithelial cells, keratocytes, and endothelial cells expressed at least two distinct N-linked oligosaccharide subsets, of the non-bisected, biantennary and bisected, bi-/triantennary types. Corneal scars stained variably with the lectin subsets described above, and with Maclura pomifera agglutinin. Lattice dystrophy corneas showed a loss of the oligosaccharide expression observed on the plasma membranes of normal epithelial cells, and there was concurrent deposition of extracellular glycoprotein within the corneal stroma, which was of the same oligosaccharide subsets as were lost from the epithelial cell plasma membranes. This extracellular stromal glycoprotein was far more widely deposited than the amyloid and extended well beyond the stromal scarring. We propose that these observations are related and that in lattice corneal dystrophy a glycoprotein(s) is shed from the plasma membranes of epithelial cells and sequestrated within the corneal stroma, where it subsequently stimulates amyloid deposition.

Graft failure in human donor corneas due to transmission of herpes simplex virus.

AIM: To report the clinical consequences of contamination of human donor corneas by herpes simplex virus (HSV) in organ culture. METHODS: Two patients without previous history of ocular HSV infection underwent penetrating keratoplasty (PK), one for keratoconus and the other for Fuchs' endothelial dystrophy. One patient suffered primary graft failure while the other developed a persistent epithelial defect, ultimately resulting in graft failure. Viral culture of swabs taken from both corneas during the early postoperative period was undertaken. The failed donor corneas were examined histopathologically by immunohistochemistry (IHC) for HSV-1 antigens, transmission electron microscopy (TEM), and by polymerase chain reaction (PCR) for HSV DNA. Both failed corneas were replaced within 6 weeks of the initial surgery. The records of the fellow donor corneas were also examined for evidence of infection. RESULTS: HSV was cultured from both corneas during the early postoperative period. Histology of both donor corneas demonstrated a thickened corneal stroma with widespread necrosis of keratocytes and loss of endothelial cells. IHC showed keratocytes positive with antibodies to HSV-1 antigens. TEM demonstrated HSV-like viral particles within degenerating keratocytes. PCR performed on the failed corneal grafts was positive for HSV-1 DNA, whereas PCR performed on the excised host corneal buttons was negative in both patients. Records of the fellow donor corneas showed that one cornea was successfully transplanted into another recipient after 18 days in organ culture, whilst the other was discarded because of extensive endothelial cell necrosis noted after 15 days in organ culture. CONCLUSION: HSV within a donor cornea may cause endothelial destruction in organ culture and both primary graft failure and ulcerative keratitis after transplantation. Endothelial necrosis of a donor cornea in culture also raises the possibility of HSV infection within the fellow cornea.

Late onset lattice corneal dystrophy with systemic familial amyloidosis, amyloidosis V, in an English family.

AIMS: To establish a clinical and molecular diagnosis in a family with late onset lattice corneal dystrophy. METHODS: Linkage analysis, single strand conformation polymorphism (SSCP) analysis, and direct sequencing of genomic DNA were performed. A review of the patients' clinical symptoms and signs was undertaken. RESULTS: Linkage to chromosome 9q34 was established and a mutation in the gelsolin gene was found in affected individuals. Numerous symptoms experienced by the patients were attributable to this mutation. CONCLUSION: A diagnosis of amyloidosis type V (familial amyloidosis, Finnish type, FAF/Meretoja syndrome/gelsolin related amyloidosis) was made. This is the first case of amyloidosis type V described in the UK. This emphasises the importance of recognition of the extraocular manifestations of eye disease both in the diagnosis and management of the patient. In addition, these findings can help molecular geneticists in their search for disease-causing mutations.

Penetrating keratoplasty for pseudophakic corneal oedema.

AIMS: The study was designed to investigate the results of penetrating keratoplasty (PK) for pseudophakic corneal oedema (PCO). METHODS: Retrospective analysis of 80 consecutive patients (82 eyes) who underwent PK for PCO between the years 1980-1992 with a minimum follow up of 12 months. RESULTS: PKs for PCO have accounted for as many as 20% of all grafts performed in the hospital in recent years. The interval between cataract extraction and PK ranged from 6 to 161 months (mean 51 months). The intraocular lens was removed in 45 (55%), left in situ in 30 (37%), and exchanged in seven (8%) of cases respectively. Of the intraocular lenses involved 62% were iris supported, 31% angle supported, and 7% were posterior chamber lenses. Actuarial analysis shows graft survival to be 91% at 1 year and 86% at 2 years after surgery. The likelihood of graft survival was significantly enhanced by removal of the intraocular lens (p < 0.01). A corrected Snellen visual acuity worse than 6/60 was present in 36% of patients with a clear corneal graft. Ocular comfort was achieved in all patients with a clear corneal graft. CONCLUSION: PK for PCO resulted in a disappointing visual result in a large proportion of patients. PK was, however, successful in relieving pain and corneal ulceration when present.

Long term results of diode laser cycloablation in complex glaucoma using the Zeiss Visulas II system.

AIM: To investigate the safety and efficacy of the Zeiss Visulas II diode laser system in the reduction of intraocular pressure (IOP) in patients with complex glaucoma. METHODS: The authors analysed the medical records of patients who underwent trans-scleral diode laser cycloablation (TDC) at the Manchester Royal Eye Hospital during a 34 month period. 55 eyes of 53 patients with complex glaucoma were followed up for a period of 12-52 months (mean 23.1 months) after initial treatment with the Zeiss Visulas II diode laser system. RESULTS: Mean pretreatment IOP was 35.8 mm Hg (range 22-64 mm Hg). At the last examination, mean IOP was 17.3 mm Hg (range 0-40 mm Hg). After treatment, 45 eyes (82%) had an IOP between 5 and 22 mm Hg; in 46 eyes (84%) the preoperative IOP had been reduced by 30% or more. The mean number of treatment sessions was 1.7 (range 1-6). At the last follow up appointment, the mean number of glaucoma medications was reduced from 2.1 to 1.6 (p<0.05). In 10 eyes (18%), post-treatment visual acuity (VA) was worse than pretreatment VA by 2 or more lines. CONCLUSIONS: Treatment with the Zeiss Visulas II diode laser system can be safely repeated in order to achieve the target IOP. Treatment outcomes in this study were similar to those from previously published work using the Iris Medical Oculight SLx laser.

Diurnal variations in human corneal thickness.

AIM: To elucidate the diurnal variation in human corneal thickness over a 48 hour period. METHOD: Changes in central corneal thickness were monitored in eight healthy subjects (four male, four female) aged between 10 and 63 years using an ultrasonic pachymeter. Measurements were made over a 48 hour period-immediately before sleep, immediately upon waking and at 15, 30, 45 minutes, 1, 1.5, 2, 2.5, 3 hours, and at 2 hour intervals thereafter throughout the remainder of each day. RESULTS: The mean corneal thickness for the group (SD) was 546 (14) microns, with a mean overnight increase of 5.5% (2.9%) (range 1.9-12.6%) and a maximum diurnal increase of 7.2% (2.8%) (range 2.1-14.3%). Individual differences in the extent of diurnal and overnight variation occurred within the group. For three subjects, the first reading taken on waking was not the highest and corneal thickness continued to increase. CONCLUSION: These data confirm an increase of corneal thickness during sleep, but also reveal considerable variation during waking hours. Thus, the overnight changes in corneal thickness are not truly representative of diurnal variations in human corneal thickness and, in fact, much greater diurnal variation occurs than the 3.0-4.4% previously reported.

Anterior segment dysgenesis in mosaic Turner syndrome.

AIMS/BACKGROUND: Females with Turner syndrome commonly exhibit ophthalmological abnormalities, although there is little information in the literature documenting findings specific to Turner syndrome mosaics. Ophthalmic findings are described in four patients with mosaic Turner syndrome. All had anterior chamber abnormalities and all four had karyotypic abnormalities with a 45, X cell line. The possible relation between the karyotypic and the phenotypic findings in these patients is discussed. METHODS: Four girls with mosaic Turner syndrome underwent a full ophthalmological assessment, including examination under anaesthesia where indicated. RESULTS: Three of the four patients presented with congenital glaucoma. Two had the karyotype 45, X/46, X, idic(Y) and one a 45, X/47, XXX karyotype. The remaining child had a Rieger malformation of the iris and the karyotype 45, X/46, X, r(X). CONCLUSIONS: These findings suggest that Turner syndrome mosaicism (where there are two abnormal cell lines) is associated with anterior segment dysgenesis. The findings in these four patients are compared with those seen in other mosaic phenotypes and it is postulated that the presence of two or more genetically different cell lines may have an adverse effect on anterior segment development.

Endothelial cell loss due to repeated traumatic wound dehiscence after penetrating keratoplasty.

A patient with keratoconus suffered two traumatic ruptures of her corneal graft wound, both of which were successfully repaired with restoration of graft clarity. There were also two apparently unrelated episodes of rejection. The endothelium was monitored by specular microscopy during this period. Our findings suggest that the insult to a transplanted cornea from an episode of rejection may be greater than that from traumatic wound rupture.

Prediction of refractive outcome in penetrating keratoplasty for keratoconus.

We carried out a retrospective study to evaluate the relationship between vitreous cavity length, graft size, and final spherical equivalent refraction after penetrating keratoplasty (PK) for keratoconus. We found a straight-line relationship between vitreous cavity length and spherical equivalent for a one-surgeon series using the same technique throughout. The use of 0.25-mm undersized grafts shifted the results an average of 2.2 Dioptres in a more hypermetropic direction (p = 0.07 for the whole group, p < 0.01 for paired eyes). Hence the final spherical equivalent following PK for keratoconus can be predicted. Also, by altering the size of the donor graft button, the final refraction can be manipulated to some extent towards acceptable ametropia or to match the refraction of the fellow eye.

Disposable soft contact lens ulcers: a study of 43 cases seen at Manchester Royal Eye Hospital.

We report an outbreak of 43 episodes of presumed microbial keratitis in 42 disposable soft contact lens wearers seen in the Accident Room of Manchester Royal Eye Hospital during a period of 20 months, and compare this with the general incidence of contact lens-related corneal infection found in a retrospective survey of 6 months' Accident Room attendances during the same period. Thirty-seven patients had worn Acuvue lenses, three had worn Nuvue, and there was no record in two cases. Corneal scrapes were taken for microbiological examination in 27 patients, and 6 of these were culture positive. Conjunctival swabs were taken from eight eyes and one was culture positive. The contact lenses of 11 patients were sent for culture and all grew pathogenic organisms. Pseudomonas spp. were the most common organisms grown, having been found in three of six corneal scrapes and six of 11 contact lens cultures. All affected eyes responded promptly to cessation of contact lens wear and topical antibiotic therapy, with none sustaining severe or permanent visual loss. Reasons for the associated high risk of microbial keratitis are discussed. Thirty-three of the 42 patients responded to a questionnaire regarding lens wear and care and their responses are reported. In consequence, we consider disposable soft contact lenses to be relatively high-risk devices for the cosmetic management of simple myopia, and their continued use must be called into question.

An ultrastructural investigation into proteoglycan distribution in human corneas.

PURPOSE: We report an investigation into the distribution of proteoglycans (PGs) in normal, organ-cultured and dextran-treated human corneas. METHODS: Immunogold labeling was carried out at the electron microscope level to localize keratan sulphate (KS), chondroitin sulphate (CS), and heparan sulphate (HS) PGs. RESULTS: High levels of labeling for CS was found in the epithelium, endothelium, and keratocytes, with light labelling present in the basement membranes and the corneal stroma. Labeling for HS was present in the epithelium, endothelium, and keratocytes, with intense labeling present at the endothelium/Descemet's membrane interface and the epithelium/Bowman's layer interface. Large filaments were also observed in these regions in cuprolinic blue-stained specimens. Keratan sulphate was present at high levels in the stroma and the basement membranes with low levels present within the keratocytes, epithelium, and endothelium. The pattern of KS labeling along the collagen fibrils in the stroma sometimes showed evidence of periodicity. Organ-cultured corneas had extensive collagen-free "lakes," the interior of which immunolabeled positively for KS and showed staining with cuprolinic blue. The lakes were greatly reduced in the dextran-treated samples. CONCLUSION: This investigation determined the ultrastructural distribution of KS, CS, and HS PGs in human cornea and showed that organ culture is associated with a change in distribution of stromal PGs.

The effect of topical 0.5% triamterene suspension on the intraocular pressure of open angle glaucoma patients. A single dose study.

The effect of a topical 0.5% triamterene suspension on the intra-ocular pressure of 15 open angle glaucoma patients was investigated. On the first day measurements were made at 09.00, 12.00 and 16.30 hours without treatment. On the second day measurements were made at 09.00 hours and 1, 2, 4 and 6 hours following instillation of the suspension into the eye. Without treatment there were no significant changes in intra-ocular pressure. After topical triamterene the maximum group mean pressure reduction was -4.7 mm Hg at 6 hours and mean intra-ocular pressures were less than 22 mm Hg at both 4 and 6 hours. There was also a notable decrease in intra-ocular pressure in two thirds of the contralateral untreated eyes which was not attributable to diurnal variation. No local or systemic side effects were observed.