Dosimetry for a study of low-dose radiation cataracts among Chernobyl clean-up workers.

A cohort of 8,607 Ukrainian Chernobyl clean-up workers during 1986-1987 was formed to study cataract formation after ionizing radiation exposure. Study eligibility required the availability of sufficient exposure information to permit the reconstruction of doses to the lens of the eye. Eligible groups included civilian workers, such as those who built the "sarcophagus" over the reactor, Chernobyl Nuclear Power Plant Workers, and military reservists who were conscripted for clean-up work. Many of the official doses for workers were estimates, because only a minority wore radiation badges. For 106 military workers, electron paramagnetic resonance (EPR) measurements of extracted teeth were compared with the recorded doses as the basis to adjust the recorded gamma-ray doses and provide estimates of uncertainties. Beta-particle doses to the lens were estimated with an algorithm devised to take into account the nature and location of Chernobyl work, time since the accident, and protective measures taken. A Monte Carlo routine generated 500 random estimates for each individual from the uncertainty distributions of the gamma-ray dose and of the ratio of beta-particle to gamma-ray doses. The geometric mean of the 500 combined beta-particle and gamma-ray dose estimates for each individual was used in the data analyses. The median estimated lens dose for the cohort was 123 mGy, while 4.4% received >500 mGy.

Cataracts among Chernobyl clean-up workers: implications regarding permissible eye exposures.

The eyes of a prospective cohort of 8,607 Chernobyl clean-up workers (liquidators) were assessed for cataract at 12 and 14 years after exposure. The prevalence of strictly age-related cataracts was low, as expected (only 3.9% had nuclear cataracts at either examination), since 90% of the cohort was younger than 55 years of age at first examination. However, posterior subcapsular or cortical cataracts characteristic of radiation exposure were present in 25% of the subjects. The data for Stage 1 cataracts, and specifically for posterior subcapsular cataracts, revealed a significant dose response. When various cataract end points were analyzed for dose thresholds, the confidence intervals all excluded values greater than 700 mGy. Linear-quadratic dose-response models yielded mostly linear associations, with weak evidence of upward curvature. The findings do not support the ICRP 60 risk guideline assumption of a 5-Gy threshold for "detectable opacities" from protracted exposures but rather point to a dose-effect threshold of under 1 Gy. Thus, given that cataract is the dose-limiting ocular pathology in current eye risk guidelines, revision of the allowable exposure of the human visual system to ionizing radiation should be considered.

Bilateral anterior lenticonus: Scheimpflug imaging system documentation and ultrastructural confirmation of Alport syndrome in the lens capsule.

BACKGROUND: Alport syndrome is a combination of proteinuria, hematuria, and neurosensory high-frequency deafness. Bilateral anterior lenticonus may be a late sign. Diagnosis relies on characteristic electron microscopy changes of glomerular basement membranes in renal biopsy specimens. PATIENT: A 38-year-old man was seen for progressive visual acuity loss (20/400 OU; best-corrected visual acuity, 20/60 OD and 20/50 OS). Findings from slitlamp examination included bilateral anterior lenticonus and central posterior subcapsular cataract, documented using a modified Scheimpflug imaging system. Retinal pathology was not present. On detailed questioning, a history of microhematuria and proteinuria since childhood and progressive high-frequency deafness for years were discovered. The family history was negative for nephropathies, deafness, or eye diseases. Cataract extraction rehabilitated the patient's vision. RESULTS: Electron microscopy of a fragile capsulorhexis specimen showed typical thinned basal lamina with basement membrane disruptions. CONCLUSIONS: Anterior lenticonus is a rare bilateral progressive developmental anomaly. More than 90% of cases are associated with Alport syndrome. For diagnosis of Alport syndrome, the presence of 3 of 4 criteria is required: family history positive for Alport syndrome, progressive intra-auricular deafness, characteristic eye anomalies, and positive findings from glomerular ultrastructural examination. We believe that ultrastructural proof of anterior lenticonus may also be provided in the lens capsule. Arch Ophthalmol. 2000;118:895-897

[Topical administration of metronidazole gel as an effective therapy alternative in chronic Demodex blepharitis--a case report]. / Lokale Anwendung von Metronidazol-Gel als wirksame Therapiealternative in der Behandlung der chronischen Demodex-Blepharitis--ein Fallbericht.

BACKGROUND: Blepharoconjunctivitis is the commonest manifestation of ocular rosacea. Cilia epilation proves Demodex folliculorum, considered an etiologic factor in rosacea. Complications and differential diagnosis include dry eyes, seborrheic, bacterial and allergic blepharoconjunctivitis. Treatment involves lid scrubs and mercury ointment, its duration is limited to 6 weeks under frequent control due to corneal toxicity of mercury. HISTORY AND SIGNS: 30-year-old female with complaint of red, irritated eyes for 21 years, resistant to antibiotics and antiallergics. General medical history unremarkable, mercury allergy. Acuity: R/L 20/20. Biomicroscopy: red, thickened eyelid margins, crusty debris on rarefied, partially broken lashes, conjunctival telangiectasia, low tear meniscus, further ophthalmologic examination unremarkable. DIAGNOSIS: chronic Demodex blepharoconjunctivitis. THERAPY AND OUTCOME: Conventional treatment was contraindicated due to mercury allergy. Alternative oral minocycline 100 mg daily brought no subjective nor objective relief. Combination of lid scrubs and 2% Metronidazole gel relieved symptoms and halved number of mites after 1 month, lashes grew again after 2 months. Treatment was discontinued after 6 months as Demodex folliculorum proof remained negative. No relapse occurred during 1 year. CONCLUSIONS: Topical Metronidazole 2% proved to be an effective treatment of chronic Demodex blepharoconjunctivitis in our case and thus may offer a new and save alternative to existing therapies. Neither ocular nor systemic side effects occurred. Controversial theories on the aetiology of blepharitis are discussed.

[Lisch nodules. Markers of neurofibromatosis 1 and immunohistochemical references for neuroectodermal differentiation]. / Lisch-Knötchen. Marker der Neurofibromatose I und immunhistochemische Hinweise für eine neuroektodermale Differenzierung.

Iris nodules in neurofibromatosis I have become an important tool in the differential diagnosis of phakomatoses. The clinical appearance and importance of these nodules first recognized by Karl Lisch in Munich in 1937. The diagnosis and differential diagnosis of Lisch nodules are illustrated. The importance of iris nodules in genetic counselling of patients and their relatives is discussed, with emphasis on monosymptomatic cases. Histologically Lisch nodules are formed by aggregations of oval to round cells that form dome-shaped papules on the anterior layer of the iris. Immunohistochemically these cells are characterized by positive staining with antibodies against vimentin and S-100 protein. This proves their ectodermal differentiation. Thus Lisch nodules can be seen as a direct manifestation of neuroectodermal disturbances in neurofibromatosis I.

[Long-term radiation damage to the skin and eye after combined beta- and gamma- radiation exposure during the reactor accident in Chernobyl]. / Langzeitstrahlenschäden an Haut und Auge nach kombinierter beta- und gamma-Strahlenexposition während des Reaktorunfalls in Tschernobyl.

BACKGROUND: In April 1986, numerous reactor workers and firemen were exposed to high doses of ionizing radiation during the Chernobyl nuclear power plant accident. Apart from high ambient gamma-ray exposures they received inhomogeneous contamination with beta-rays from fission products, resulting in severe skin exposure. PATIENTS AND METHODS: Sixteen of these so called Liquidators were repeatedly examined between 1991 and 1996. Their doses ranged from 0.35 to 9 Gy, partly confirmed by determination of chromosomal aberrations. Ophthalmologic examination included non-subjective assessment of lenticular radiation damage with an electronic Scheimpflug camera system. Digital image analysis allowed the comparison of opacification units to previous and normal findings. RESULTS: Four Liquidators had posterior subcapsular opacifications in different degrees, one presented only after cataract extraction. One patient had dense corticonuclear cataracts and pseudoexfoliation-like changes. Three men had severe dry eye syndrome. Eight men had no ocular complications. Retinal radiation damages were absent. 15 Liquidators suffered from severe chronic cutaneous radiation damage, which led to amputations in 3 cases. CONCLUSIONS: A relation between ocular and dermatological findings was not expected and could, in fact, not be seen. The comparison of posterior subcapsular opacification and doses revealed no distinct relation, although it indicates a correlation that is here not quantified. The doses represent organ doses for the bone marrow which is primarily exposed to deeper penetrating gamma-radiation. Thus they need not be correlated with combined beta- and gamma-doses in organs such as skin and eye because the superficial exposure due to beta-radiation may differ greatly form the whole body exposure as reflected in bone marrow doses.