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PURPOSE Patients with beta-thalassemia (beta-tha) represent a group with lifelong transfusion-dependent anemias. This study aimed to describe the conjunctival changes and tear film parameters in these patients. METHODS A total of 52 patients (104 eyes) with beta-tha major and 22 normal control subjects (44 eyes) were studied during 1999 through 2000. Tear film break-up time (BUT), Schirmer test, rose Bengal staining, and cytologic evaluation of the conjunctival epithelium were performed in all subjects. The Papanicolaou and May-Grumwald-Giemsa staining procedures were performed on all smears. Patients and control subjects were compared for tear function parameters and conjunctival changes. RESULTS The BUT, Schirmer test, and rose Bengal staining values were significantly lower (P < 0.001) in beta-tha patients than in control subjects. Keratinized cells were observed in conjunctival samples in 41% of patients, with a decrease in the number of goblet cells per slide in 64% of patients. In 9% of beta-tha patients, there were a slightly greater number of inflammatory cells than in control eyes. CONCLUSION Ocular surface disorder of these patients was characterized by goblet cell loss and conjunctival squamous metaplasia. Our findings were correlated positively with the variable age. Epithelial damage by toxic reaction and disorder of tear quality and quantity are implicated as important factors in the pathogenesis of the ocular surface disease in beta-tha patients.

We obtain maximum likelihood estimates of the parameters when the observations on the response variable in a repeated measures design are truncated above a cutpoint. The maximum likelihood equations are solved iteratively using an EM-like procedure. It is observed that these estimates have smaller mean squared error than recently proposed iterative weighted least-squares estimates. The results are applied to data arising from a study of dioxin elimination in Air Force veterans. Published in 2000 by John WileySons, Ltd.

We summarize the distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) in 1,302 Air Force veterans who serve as controls in a 20-year prospective epidemiologic study of health and exposure to herbicides and their dioxin contaminant in Air Force veterans of Operation Ranch Hand, the unit responsible for aerial spraying of Agent Orange and other herbicides in Vietnam. We present statistics summarizing the dioxin distribution overall and by stratum of age and body mass index of these veterans. The average dioxin measurement was 4.23 and the standard deviation was 2.53 parts per trillion. With 95% confidence, 99% of the distribution is less than or equal to 10.4 parts per trillion.

To evaluate the efficacy of intracameral recombinant tissue plasminogen activator (r-TPA) in prevention of fibrinous effusion after lensectomy, anterior vitrectomy, and posterior chamber intraocular lens (PCIOL) implantation in patients with congenital cataract.The study was done as a double masked randomised clinical trial between April 2002 and November 2003 in Farabi Eye Hospital. 34 eyes of 26 patients with congenital cataract were included in the study and randomised into two groups (18 cases and 16 controls). Mean age was 8.1 years (3--14 years). Each eye underwent lensectomy and anterior vitrectomy with PCIOL implantation. At the end of surgery 20 microg r-TPA was injected intra-camerally in the case group. The control group received only balanced salt solution. All patients received periocular, systemic, and topical steroids after surgery. Patients underwent follow up examinations for 3 months.The incidence of intraocular fibrin membrane formation was significantly lower in the case group on days 1, 3, 7, 14 (p=0.02, p=0.01, p=0.01, and p=0.01, respectively, chi(2) test), but there was no significant difference on days 30 and 90. The frequency of pigmented intraocular lens precipitates was significantly lower in the case group at the end of the third month (p0.001, chi(2) test). No gross ocular side effects were noted after r-TPA injection.It seems that prophylactic intracameral r-TPA is effective in prevention of fibrinous effusion at least in the first 2 weeks after cataract extraction in the paediatric age group and decreases the incidence of pigmented IOL precipitates.

A study was conducted on the reliability of the serum dioxin measurement of enlisted Ranch Hands veterans participating in the Air Force Health Study using paired serum dioxin measurements. The 46 veterans were not randomly selected, but their demographic characteristics, health, and dioxin levels were similar to those of 404 other enlisted Ranch Hand veterans who had a single dioxin measurement made in 1987. The average time between the measurements was 0.61 years, the first measurement made from blood drawn on 10 April 1987 and the second from blood collected at a subsequent physical examination. In original unit, the coefficient of reliability was 0.87 (95% confidence interval: 0.76, 0.94) when the first measurement was at or below 50 parts per trillion. The measurement had no reliability in original units when the first measurement was greater than 50 parts per trillion. After a logarithmic transformation, the coefficient of reliability was 0.96 (95% confidence interval: 0.93 to 0.98). These results suggest that the serum dioxin measurement should not be used in original units for any purpose when the value exceeds 50 parts per trillion. The measurement is, however, highly reliable after a logarithmic transformation over the entire range of concentrations. Other studies using the same analytical method to measure dioxin in serum could similarly benefit if the measurement used is on the natural logarithm scale.

We conducted complete eye examinations and retinal function tests on nine patients who had undergone jejunoileal bypass (JIB) surgery and subsequently had low serum vitamin A levels. All patients had manifested clinically demonstrable keratoconjunctival xerosis; in addition, two had abnormally high dark-adaptation final thresholds, and two had concomitant implicit prolongation in the electroretinogram. The age-matched control groups that consisted of 14 patients with various gastrointestinal disorders and four asymptomatic volunteers showed fewer or no ocular abnormalities. Our findings suggest that, even though patients who underwent JIB surgery may manifest keratoconjunctival xerosis and have low serum vitamin A levels for several months to years, retinal function will remain normal until the tissue stores of vitamin A are depleted. A long-term ophthalmologic follow-up of JIB patients, therefore, is recommended.

We performed ocular examinations on 58 corticosteroid-treated pediatric patients with inflammatory bowel disease (IBD) and on 58 age-matched controls. Posterior subcapsular cataracts (PSC) were detected in 12 of the 58 treated patients (20.7%) and in none of the controls. The difference in mean intraocular pressure (IOP) between the treated patients (15.89 +/- 4.11 mm Hg) and control subjects (13.63 +/- 2.35 mm Hg) was significant statistically (P0.001). Twenty-one patients (36.2%) were characterized as "IOP responders" (IOPor = 20 mm Hg, change in IOPor = 6 mm Hg between visits, or a difference in IOPor = 6 mm Hg between the two eyes). Formation of PSC was not correlated significantly (P0.05) with the total dose of prednisone, duration of treatment, average daily dose, or number of days on high doses (or = 25 mg). Raised IOP was correlated (P = 0.005) only with average daily dose (12.4 +/- 10.9 mg/day; range, 0-47 mg/day) 30 days before examination. When the dose of corticosteroid was reduced to10 mg/day, 2 patients manifested regression of PSC, and 12 IOP responders showed a decrease in IOP to within 2 SD of the mean control IOP. Only 3 of the 58 treated patients (5.2%) manifested both PSC and raised IOP. A significant inverse correlation (P = 0.02) was established between IOP at first examination and formation of PSC. We propose that the mechanisms for steroid-induced lens opacities and raised IOP do not share the same genetic basis. Because 52% of these children developed either PSC or raised IOP with prednisone therapy, we advocate careful ophthalmologic monitoring of pediatric patients receiving corticosteroids for IBD or any other condition.

We report the case of a patient with pseudophakic cystoid macular edema whose visual acuity improved promptly with oral administration of 500 mg of acetazolamide extended-release capsules BID for two weeks. However, vision worsened again within two weeks of discontinuation of the treatment. On resumption of acetazolamide therapy for three weeks, and its slow withdrawal during the following three weeks, the macular edema eventually resolved, and vision returned to normal. Our observation provides a direct correlation of the resolution of pseudophakic cystoid macular edema with acetazolamide therapy and shows the importance of tapering the doses of this regimen.

A series of 75 spoilt soft lenses with opacities (mostly manifesting as discrete spots or as large areas of cloudiness, chalk-white in appearance) were subjected to histochemical, electron microscopical, electron probe x-ray microanalytical, x-ray diffraction, atomic absorption spectro-photometric, and biochemical analyses. The results showed that in many cases calcium was implicated in the deposit formation and that a broad correlation existed between the amount of calcium present and the degree of opacification. The possible mode of calcium deposition and resulting implications in lens intolerance are discussed. It is advocated that a search should be made for a modified or new soft lens material which does not permit calcium deposition, and that the medical practitioner should strive towards improved assessment of the systemic and ocular conditions which may help in identifying patients at risk of early lens failure.

The clinical features of pigmented lens striae were studied biomicroscopically in seven patients. The lenses of three of these, obtained by cataract surgery, were examined by electron microscopy to determine the structure of the striae. We concluded that the striae are not formed by remnants of tunica vasculosa lentis, as earlier workers believed, but consist of fine fibrils of zonular bundles entrapping pigment granules of uveal origin.

We encountered two clinically similar but genetically unrelated cases of a disorder characterized by an unusual white pupillary-iris-lens membrane with extension to a prominent Schwalbe's line, the membranes were vascularized and their appearance changed over time. In both cases the abnormality was unilateral. Anomalous chamber angles were seen on gonioscopy. The clinical appearance is similar to a combination of iridogoniodysgenesis and pupillary membrane. However, our two cases are unique and fit into neither category. We postulate that this is a new entity consisting of an anomalous chamber angle and iris-lens membrane resulting from a localized iris (pupillary membrane), infarct with secondary neovascularization, during formation of the chamber angle.

Three patients who initially presented to the ophthalmologist with a history of gradual deterioration of visual acuity showed, on biomicroscopic examination, a linear meshwork of opacities in the vitreous attached to the posterior surface of the lens in the form of pseudopodia lentis. Amyloidosis of the vitreous associated with systemic amyloid disease was diagnosed because of the characteristic nature of the opacities. This was confirmed initially in two of the cases by light and electron microscopical examination of a biopsy of the clinically normal conjunctiva, subsequently by systemic investigations, and finally, by direct histochemical and elecron microscopical examination of the vitreous which became available after vitrectomy in all three cases. It was not possible to examine other members of the families. The relevant literature on vitreous amyloidosis is reviewed in relation to our own findings and the importance of a diagnostic conjunctival biopsy is emphasized. This paper is the first British report on primary vitreous amyloidosis. The pathogenesis of vitreous amyloid opacities is discussed in the light of current concepts of amyloidosis. Since the vitreous opacities due to amyloid deposits appear to be one of the manifestations of systemic amyloid disease, surgical removal of the opacities by vitrectomy may not produce longlasting results. Moveover, in contemplating surgical treatment the ophthalmologist should bear in mind the poor prognosis of systemic amyloidosis.

We report the histopathologic findings in a human eye enucleated after insertion of three nonmagnetic, metallic alloy tacks for treatment of a giant retinal detachment. Five months after surgery one of the tacks was detected in the anterior chamber. Two tacks remained in situ and induced a localized glial reaction, breaks in Bruch's membrane, disappearance of the retinal pigment epithelium and choriocapillaris immediately around the tack, and a variable extent of chorioretinal adhesion. The penetration of the tacks in the choroid and sclera was associated with a localized scar and only a mild inflammatory reaction, but all tacks themselves were free of inflammatory cells and degradation. The two tacks remaining in place were tolerated by the posterior segment. After comparing and contrasting our findings with those documented in the rabbit model, we conclude that overcoming dislodgement problems will require improved insertion techniques and tack design.

Band-like structures, clinically similar to Haab's striae, occur in posterior polymorphous dystrophy (PPMD) and are often confused with them. The difference in clinical appearance based on difference in histopathology allows a clear differentiation. The edge of Haab's striae are thickened, curled, and secondarily proliferate Descemet's membrane, while the area between the edge is thin and smooth. Posterior polymorphous dystrophy bands are the exact opposite. The band is a thickening of Descemet's membrane between the edges with thinner, more normal Descemet's membrane outside of them. PPMD bands may be associated with typical vesicles or appear as the only sign of dystrophy, even in the eyes of patients with a known family history.

The histopathological manifestations in four eyes from two male patients with the oculo-cerebro-renal syndrome of Lowe included a small, discoid, cataractous lens, peculiar capsular and epithelial changes with aberrant formation of collagenous fibrous tissue, polar lenticular changes with anterior vitreous condensation, embryonic anterior chamber angle with anterior displacement of rudimentary ciliary processes, segmental hypoplasia of iris dilator muscle, and Lange's folds with peripheral retinal cystoid changes. Additional findings in one of the cases included bilateral corneal keloids, vitreous organization, hyalinized retinal vessels, and mild gliosis. We suggest that the congenital ocular abnormalities in Lowe's syndrome are related to an as yet unidentified, inherited enzymatic and/or biochemical defect, and that they progress further because of an abnormal aqueous humour environment. The role of aminoaciduria and mucopolysaccharidosis in the pathogenesis of systemic and ocular defects is discussed in the light of recent investigations.

A firm, round tissue mass, measuring approximately 12 mm in diameter, was excised from a 5-month-old boy who had a history of a gradually enlarging swelling in the left lower nasal eyelid since birth. Histologically and ultrastructurally, the lesion appeared benign and was composed of a dense connective tissue stroma in which nests, lobules, tubules, cords, and sheets of large, pale-staining cuboidal and elongated epithelial cells were surrounded by an irregular, thick PAS-positive basement membrane having focal excrescences. The interior of the epithelial islands contained "bladder" cells, cellular debris, granuloamorphous material, and foci of dystrophic calcification; an unusual feature of the lesion was the formation of numerous psammoma bodies. Tumors of lenticular anlage are rare and probably result due to displacement of migration of the inferior lens placode cells; alternatively, it may originate from an additional locus of lens vesicle in the primitive surface ectoderm of the lower lid. The lesion enlarges because of the differentiation of the ectopic lenticular cells in an abortive attempt to form a lens within the extraocular and mesodermal environment of the lid.