Retinal toxicity of intravitreal tenecteplase in the rabbit.

AIM: To investigate the retinal toxicity of intravitreal injection of a novel fibrinolytic tenecteplase in rabbit eyes. METHODS: Tenecteplase (25-350 micro g in 0.1 ml BSS) was injected into the vitreous cavity of normal rabbit eyes. Control (fellow) eyes received 0.1 ml of BSS. One day, 1 week, and 2 months post-injection, the eyes were examined by slit lamp biomicroscopy, indirect ophthalmoscopy, and electroretinography, and then harvested for histopathological examination. RESULTS: No evidence of retinal toxicity was seen with tenecteplase doses up to and including 50 micro g. At a dose of 150 micro g ophthalmoscopy was normal, but histology showed mild retinal damage in the inner nuclear layer and electroretinography showed a temporary reduction in B-wave amplitude. At doses of 200 micro g and above, there was evidence of retinal toxicity on electroretinography, ophthalmoscopy, and histology. Ophthalmoscopic findings included vitreal fibrosis, retinal necrosis and tractional retinal detachment and light microscopy revealed necrosis of retinal pigment epithelium and other retinal layers. Damage was centred around the injection site but was more widespread with the higher doses. CONCLUSION: A dose of 50 micro g tenecteplase appears safe for intravitreal injection in the rabbit. Tenecteplase could have potential applications in the treatment of submacular haemorrhage and retinal vein occlusion.

Ophthalmic manifestations of tuberous sclerosis: a population based study.

BACKGROUND/AIMS: Tuberous sclerosis complex (TSC) has retinal and non-retinal ophthalmic manifestations. This study was designed to determine the prevalence of the ophthalmic manifestations and of refractive errors in a population of patients with TSC. METHODS: 179 patients identified were in a prevalence study of TSC in the south of England and 107 of these agreed to full ophthalmic examination which was successful in 100. Ophthalmic examination included examination of the eyelids, cover test, examination of the irides, dilation funduscopy using both direct and indirect ophthalmoscopy, and refraction using retinoscopy. Myopia was defined as a spherical equivalent <-0.5D and hyperopia as a spherical equivalent >+0.5D. RESULTS: Retinal hamartomas were seen in 44 of the 100 patients. The commonest morphological type of hamartoma seen was the flat, translucent lesion in 31 of the 44 patients (70%). The multinodular "mulberry" lesion was seen in 24 of the 44 patients (55%) and the transitional type lesion was seen in four of the 44 patients (9%). Punched out areas of retinal depigmentation were seen in 39 of the 100 patients but only six of 100 controls. 27% of eyes were myopic, 22% were hyperopic, and 27% had astigmatism >0.75D. Of the non-retinal findings, 39 patients had angiofibromas of the eyelids, five had non-paralytic strabismus, and three had colobomas. CONCLUSION: Apart from the higher prevalence of flat retinal hamartomas, the findings of this study compare closely with previous large clinic based series of TSC patients. Refractive findings were similar to previous studies of a similarly aged non-TSC population. This is the first series to document the statistically significant association of punched out chorioretinal depigmentation with TSC and the authors believe that it should be looked for as an aid to diagnosis.

Sub-Tenon's local anaesthesia: the effect of hyaluronidase.

AIMS: A prospective, randomised, double blind study was used to investigate the effect of hyaluronidase on the quality of block achieved with sub-Tenon's local anaesthesia. METHODS: 150 patients scheduled for elective cataract surgery were randomly allocated to either sub-Tenon's block with 3 ml lignocaine 2%/adrenaline 1:200 000 alone or with the addition of 30 IU/ml of hyaluronidase. The blocks were assessed for degree of akinesia and reduction of eyelid movement, and also post-injection and postoperative pain scores. RESULTS: Akinesia and reduction of eyelid movement measured 10 minutes after injection were significantly better in the group with hyaluronidase added to the anaesthetic solution. Postoperative pain scores were not significantly different between the two groups but the post-injection pain score was greater (marginally significant) in the group with hyaluronidase added. CONCLUSION: The addition of hyaluronidase significantly improves the quality of the motor blockade achieved with sub-Tenon's local anaesthesia, but has no effect on the sensory blockade.

Multidimensional model of racial identity: a reconceptualization of African American racial identity.

Research on African American racial identity has utilized 2 distinct approaches. The mainstream approach has focused on universal properties associated with ethnic and racial identities. In contrast, the underground approach has focused on documenting the qualitative meaning of being African American, with an emphasis on the unique cultural and historical experiences of African Americans. The Multidimensional Model of Racial Identity (MMRI) represents a synthesis of the strengths of these two approaches. The underlying assumptions associated with the model are explored. The model proposes 4 dimensions of African American racial identity: salience, centrality, regard, and ideology. A description of these dimensions is provided along with a discussion of how they interact to influence behavior at the level of the event. We argue that the MMRI has the potential to make contributions to traditional research objectives of both approaches, as well as to provide the impetus to explore new questions.