Relationship between mandibular deviation and ocular convergence.

Recent studies have confirmed the relationship between head posture, mandibular position and visual focusing. A case-controlled study was conducted to assess the occurrence of ocular convergence defects between subjects with functional mandibular latero-deviation and healthy subjects in pediatric age. Sixty subjects (the study group) presented mandibular latero-deviation classified as functional according to the use of a clinical examination and frontal and basal tele-radiography. Sixty subjects without functional mandibular laterodeviation (control group) were selected randomly from all subjects seeking pediatric dental care and matched by gender and age to study group. All one hundred and twenty subjects were submitted to orthoptic tests performed by the same operator. These results seemed to confirm that in mandibular latero-deviation subjects ocular convergence defects occurred in greater frequency than in controls underlining the importance of role of pediatric dentistry among interdisciplinary cooperation.

Eventual error caused by dehydration with pachometry.

Among the possible variables responsible for systemic errors in the acquisition of pachometric measurements, the corneal hydration condition plays a determinant role. In the present study, the authors have investigated the importance of this condition with two different pachometers (Storz Corneoscan II and Allergan Humphrey), reproducing an experimental dehydrated condition. The main datum arising from the comparison of the measurements obtained is represented by the different time course of the value of the measurement in the two groups. In fact, confronting the medium initial superimposed thickness value in the two tables (521 vs. 520 microm) there is a substantial difference in the final examination. For the first group of 60 corneas, the thickness values appear almost identical in the different intervals of time (medium initial thickness 521 vs. 512 microm final thickness). For the group examined with the solid-point machine, a decreasing thickness equal to 7% was evidenced (520 vs. 482 microm) with a significant decrease in the corneal thickness after only 45 s.

The use of ultrasound biomicroscopy in pre-operative evaluation of orbital-blepharal neoformations: report of a case.

In our study we have taken into consideration the use of ultrasound biomicroscopy (UBM) in a case of orbital-blepharal lymphoma. The advantages of this methodology, which is considered a refinement of B scan ultrasonography, compared with other instruments at present available on the market, have been described. We have tried to show how the instrument for biomicroscopic ultrasonography makes it possible to obtain images of the anterior segment of the eye in every detail; it is, therefore, capable of giving us information once only available by means of examining histopathological sections. Apart from the advantages, in this work we have also described the limits of this methodology, which in order to allow an accurate diagnosis must always be accompanied by the traditional ocular echography.

Biometric pre-operative evaluation of ocular axial length in patients subjected to corneal transplantation.

In cases of keratoconus and consequent penetrating keratoplasty, the refractive requirements of the patient determine the dimensions of the donor button and the receiving wound size. The pre-operative biometric evaluation of the axial parameters may induce the surgeon to choose an oversized button to obtain the right curvature of the cornea and avoid hypermetropia. In this study we present 20 patients transplanted between 1993 and 1995, 13 female, 7 male, aged between 23 and 45 years. These cases demonstrate the utility of this easy and economic technique.

Echographic follow-up in patients who have undergone sclero-uveotumorectomy.

A-B scan echography provides accurate information on the location, the nature, the extension of a neoplasm and the involvement of neighbouring tissues as well as on the postsurgical evolution. In this study, we intend to give accurate and useful indications to the surgeon concerning conservative surgery and the follow-up after sclero-uveotumorectomy in cases of uveal neoformations. Between January 1988 and June 1996, we examined 46 patients by means of echography before and after sclero-uveotumorectomy.

Evaluation of the echographic contribution to the parasurgical treatment of melanomas of small dimensions.

In this work we underlined the contribution of echography in the parasurgical treatment (photocoagulative) of melanomas of small dimensions. Fourteen patients were examined; some of them were treated with argon laser, others with krypton laser. The echographic examination was performed with the A-B scan technique, naturally accompanied by fluorangiography before and after the operation. An accurate echographic and fluorangiographic follow-up makes it posible to control the evolution of the lesions efficaciously. From this work it is clear how echography gives highly reliable results which allow us, therefore, both to make an adequate therapeutic decision and to evaluate the efficaciousness of the treatment itself.

Neoplasia-like echographic evidence in retinopathies of several aetiologies: a case report.

In ocular retinal pathology, several aetiological entities showing various clinical and ophthalmoscopic pictures can simulate a tumour. The contribution of echography to the diagnostic research in ophthalmology is really important and the good knowledge of the difficulties and echographic limits is essential. We specifically report a tubercular granuloma clinically and echographically simulating a ciliary-body melanoma.

Alterations of the internal reflectivity of extra-ocular muscles associated with several clinical stages of Graves' ophthalmopathy.

In the period between February 1992 and June 1996, the authors performed extra-ocular muscle echobiometry on 163 patients with Graves' disease. The aim of this study is the evaluation of changes occurring in several clinical stages. The authors noted an increase in internal muscular reflectivity in the advanced phases and an irregular structure in the early stages. Controversial results in the literature warrant mastery of the method and further research.

Measurement of corneal thickness by ultrasound after photorefractive keratectomy in high myopia.

BACKGROUND: Photorefractive keratectomy (PRK) has been used to treat myopia in human eyes since 1988. METHODS: We evaluated corneal ablation depth after excimer laser myopic photorefractive keratectomy with the Summit Technology ExciMed UV200LA laser. Preoperative refraction was: mean 9.58 diopters (D) +/- 2.01, (range 6 to 17). We used ultrasound pachometry (1640 m/sec) in 40 eyes of 33 patients. Mean follow-up was of 49.5 weeks (range 16 to 76). RESULTS: The measurement of the corneal thickness showed a reduction of the initial thickness followed by an inconsistent increase caused by wound healing and tissue proliferation. CONCLUSION: The data showed no direct correlation between diopters of refractive correction and the change in corneal thickness.

Effect of centering excimer laser PRK on refractive results: a corneal topography study.

Computer-assisted analysis of corneal topography, using an EyeSys Corneal Analysis System instrument, was performed on 20 normally sighted human eyes that underwent excimer laser photorefractive keratectomy (PRK) to correct high myopia from 6.00 to 17.00 D (mean 10.90 +/- .SD 2.90 D). Ablations utilized one or two zones, at a single time, with an ExciMed UV200 193-nanometer excimer laser (Summit Technology, Inc, Waltham, Mass). Mean follow up was 28.9 weeks (+/- 13). Decentered treatment caused an average error of 1.06 D in the attempted refractive result.

Prenatal screening for hepatitis B surface antigen. Is universal screening necessary?

Prenatal screening for hepatitis B is now recommended as a universal practice in Canada. This study questions whether that policy should apply outside large urban centres. We studied women delivering babies at the Royal Victoria Hospital in Barrie, Ont. Of 1216 women, results of HBsAg screening were available for 716; only two women, both from a high-risk group, were HBsAg positive. If selective screening is used, physicians must question patients carefully to ensure that women at risk are identified and tested.