Evidence for Extending Anomalous Miocene Volcanism at the Edge of the East Antarctic Craton.

Using field observations followed by petrological, geochemical, geochronological, and geophysical data we infer the presence of a previously unknown Miocene subglacial volcanic center ~230 km from the South Pole. Evidence of volcanism is from boulders of olivine-bearing amygdaloidal/vesicular basalt and hyaloclastite deposited in a moraine in the southern Transantarctic Mountains. 40Ar/39Ar ages from five specimens plus U-Pb ages of detrital zircon from glacial till indicate igneous activity 25-17 Ma. The likely source of the volcanism is a circular -735 nT magnetic anomaly 60 km upflow from the sampling site. Subaqueous textures of the volcanics indicate eruption beneath ice or into water at the margin of an ice mass during the early Miocene. These rocks record the southernmost Cenozoic volcanism in Antarctica and expand the known extent of the oldest lavas associated with West Antarctic rift system. They may be an expression of lithospheric foundering beneath the southern Transantarctic Mountains.

Photic maculopathy after pterygium excision.

PURPOSE: To report a patient who developed photic maculopathy after pterygium removal. METHODS: A 27-year-old woman underwent pterygium removal with a conjunctival autograft after administration of retrobulbar anesthesia. A coaxial operating microscope was used, with an estimated retinal exposure of approximately 40 minutes. RESULTS: On the first postoperative day, the patient noted a paracentral scotoma. A fluorescein angiogram on the fourth postoperative day documented a phototoxic lesion in the macula. CONCLUSIONS: Phototoxic injury to the macula may occur after pterygium removal. Ophthalmologists should take precautions to minimize prolonged intense coaxial illumination of the retina while performing any ocular microsurgery.

Pneumatic retinopexy. A two-year follow-up study of the multicenter clinical trial comparing pneumatic retinopexy with scleral buckling.

The authors report 2-year follow-up information on 179 of 198 eyes (90%) enrolled in a previously published multicenter, randomized, controlled clinical trial comparing pneumatic retinopexy (PR) with scleral buckling (SB) for the management of selected retinal detachments. Scleral buckling was compared with PR with regard to redetachment after the initial 6-month follow-up period (1% versus 1%), overall attachment (98% versus 99%), subsequent cataract surgery (18% versus 4%; P less than 0.05), preoperative visual acuity (no significant difference), and final visual acuity of 20/50 or better in eyes with macular detachment for a period of 14 days or less (67% versus 89%; P less than or equal to 0.05). Reoperations after a failed PR attempt did not adversely affect visual outcome. After 2 years, PR continues to compare favorably with SB.

The complication of pneumatic retinopexy.

There have been 26 published series with a total of 1274 detachments operated with pneumatic retinopexy. Eighty percent were reattached with a single procedure and 98% with reoperations. New breaks occurred in 13% and PVR in 4%. The complications published in 101 papers on pneumatic retinopexy in the last 5 years are analyzed as to frequency, prevention, management, and results.

The use of fundus photographs and fluorescein angiograms in the identification and treatment of choroidal neovascularization in the Macular Photocoagulation Study. The Macular Photocoagulation Study Group.

The Macular Photocoagulation Study (MPS) Fundus Photograph Reading Center has developed a standard set of methods for assessing color photographs and fluorescein angiograms on study patients. For pretreatment angiograms, these methods are used to determine the location and extent of the choroidal neovascularization. For posttreatment color fundus photographs, these methods are used to assess the extent and intensity of treatment. Although these methods were developed to judge eligibility and treatment of patients enrolled in the MPS, they provide an excellent way for all treating ophthalmologists to evaluate their patients' angiograms and to assess immediately the intensity and extent of laser photocoagulation. The technique requires a microfilm reader or slide projection device to determine the completeness of treatment. The authors superimpose independent drawings made from pre- and posttreatment photographs. The techniques described can be applied readily in clinical practice. Since persistent neovascularization is highly correlated with incomplete and/or inadequate photocoagulation treatment, clinicians may adopt these Reading Center techniques to minimize the frequency of persistent neovascularization and, possibly, to reduce the frequency of visual loss in treated eyes.

Iatrogenic choroidal neovascularization after krypton red laser photocoagulation.

A major cause for failure of krypton red laser photocoagulation in patients with exudative age-related macular degeneration has been the development of recurrent choroidal neovascularization adjacent to the previously treated areas. After reviewing the possible causes of recurrences, it is apparent that a certain number are iatrogenic, ie, induced by krypton red laser causing disruption and damage to the pigment epithelium-Bruch's membrane-choroidal complex. We describe three separate episodes in two patients of iatrogenic recurrent choroidal neovascularization after krypton red laser photocoagulation.

Foveal neovascularization in diabetic retinopathy.

Retinal neovascularization in diabetes mellitus almost always occurs at the optic disc and/or near the major nasal and temporal vascular arcades, sparing the foveal area. We examined seven eyes of seven patients with long-standing insulin-dependent diabetes mellitus who had unilateral foveal retinal neovascularization. The neovascularization originated from the perifoveal capillaries and demonstrated typical leakage on fluorescein angiography.

Macular hamartomas of the retinal pigment epithelium and retina.

Four patients with macular hamartomas of the retinal pigment epithelium and retina are described. Associated choroidal neovascularization was noted in one patient. The clinical, fluorescein angiographic, and histopathologic findings of this entity are reviewed.

Computed tomography in the management of orbital infections associated with dental disease.

Two patients developed orbital infection secondary to dental infections. In one patient the infection spread from maxillary premolar and molar teeth to the infratemporal and pterygopalatine fossa and then through the inferior orbital fissure to the subperiosteal space. A subperiosteal abscess in the posterior orbital wall developed, which subsequently spread within the muscle cone. In the second patient infection of an anterior maxillary tooth caused a pansinusitis and unilateral orbital cellulitis. In both patients computed tomographic scanning of the orbit proved valuable in localising the infection and, in one case, planning a surgical approach to the orbit. The infection in both patients responded to treatment, with no permanent visual impairment. Appropriate antibiotics and prompt identification and surgical drainage of orbital abscesses are essential for the preservation of vision in cases of orbital infection.

Management of breakthrough vitreous hemorrhage from presumed extramacular subretinal neovascularization.

Three patients developed vitreous hemorrhage secondary to breakthrough bleeding from presumed extramacular subretinal neovascularization. In one patient, the vitreous hemorrhage cleared spontaneously. In two other patients, trans-pars plana vitrectomy was performed. All patients regained 20/30 vision or better. Residual peripheral retinal pigment epithelial atrophy, organized subretinal hemorrhage, and/or subretinal fibrous membranes were present in all patients. A definite extramacular subretinal neovascular membrane was identified in one patient. Ocular diseases associated with subretinal neovascularization are tabulated. Indications for trans-pars plana vitrectomy in patients with breakthrough vitreous hemorrhage secondary to presumed extramacular subretinal neovascularization are proposed.

Adult Haemophilus influenzae type B vertebral osteomyelitis: a case report and review of the literature.

Osteomyelitis in adults due to Haemophilus influenzae is exceedingly rare. We report a case of H. influenzae type b vertebral osteomyelitis in an adult. Review of the English literature reveals one other adult patient with H. influenzae osteomyelitis, and sporadic pediatric cases. Although a variety of predisposing host resistance factors have been postulated to account for this infection, the deficiency responsible for adult infection remains undelineated. Bone biopsy is mandatory for diagnosis when blood cultures are negative. The isolation and identification of H. influenzae may be delayed because of its fastidious growth requirements. Treatment with ampicillin or chloramphenicol appear to be most efficacious considering the antibiotic sensitivities of the organism.

The clinical significance of retinitis pigmentosa without pigment: a computer assisted analysis.

Sixty-eight consecutive patients with retinitis pigmentosa were studied to determine the frequency of the non-pigmented form of the disease. There was an overall incidence of 22%. Fifty percent of all cases had no characteristic pigmentation, if the duration of night vision difficulty was three years or less. The study lends statistical support to the concept that the non-pigmented form of retinitis pigmentosa is frequently an early stage of the disease and not an unusual or atypical variant. Patient without the pigmentary changes characteristic of the disorder also showed less functional impairment: the ERG b-wave was more apt to be recordable, although impaired; and the rod threshold, as determined by dark adaptation measurement, was less elevated. The clinician should suspect retinitis pigmentosa, even in the absence of pigmentary changes, if there is a family history of the disorder, night blindness, peripheral field loss, and an impaired or non-recordable electroretinographic response.

Retinitis pigmentosa without pigment.

Sixty-eight consecutive patients with retinitis pigmentosa were studied to determine the frequency of the nonpigmented form of the disease. There was an overall incidence of 22%. Fifty percent of all cases had no characteristic pigmentation, if the duration of night vision difficulty was three years or less. The nonpigmented form of retinitis pigmentosa was frequently an early stage of the disease and not an unusual or atypical variant. Patients without the pigmentary changes characteristic of the disorder also showed less functional impairment: the electroretinographic b wave was more apt to be recordable, although impaired, and the rod threshold, as determined by dark adaptation measurement, was less elevated. The clinician should suspect retinitis pigmentosa, even in the absence of pigmentary changes, if there is a family history of the disorder, night blindness, peripheral field loss, and an impaired or nonrecordable electroretinographic response.