Michael F. Lewandowski

Pseudophakia for traumatic cataracts in children.

Purpose: The purpose of this prospective study is to evaluate the postoperative visual acuity, refractive error, intraocular pressure, and status of the posterior capsule in children with traumatic cataracts who undergo extracapsular cataract extraction and insertion of a posterior chamber lens. Methods: Extracapsular cataract extraction and primary endocapsular fixation of a posterior chamber lens implant were performed in eight children (age range, 4–17 years) with unilateral traumatic cataracts. Results: There were no intraoperative complications, and seven of eight eyes achieved 20/40 or greater spectacle visual acuity during an average follow-up interval of 10 months (range, 5–20 months). The average postoperative spherical equivalent refractive error was +0.33 diopter (D) (range, −2.25 to +2.12 D); the average postoperative anisometropia was approximately 1 D (range, 0–2.25 D). In one patient, a coagulase-negative staphylococcal endophthalmitis developed 10 days after surgery. In three eyes that had opacified posterior capsules, YAG laser capsulotomy was performed. Conclusions: These preliminary results suggest that intraocular lens (IOL) implantation may be a safe and effective method of optical correction for children with traumatic cataracts.

Treatment of Experimental Intravitreal Fibrin With Tissue Plasminogen Activator

We produced experimental intravitreal fibrin clots in rabbits that had previous gas compression of the vitreous or intact vitreous. Twenty-four hours after production of fibrin, the eyes were injected with 25 micrograms of tissue plasminogen activator or physiologic irrigation solution. In the gas compression group (n = 11), all tissue plasminogen activator-treated eyes cleared within six hours of injection; complete clearing was not seen until six days in the physiologic irrigation solution-treated eyes (n = 9). A similar response was seen in the intact vitreous group. No evidence of toxicity was observed as measured by slit-lamp biomicroscopy, intraocular pressure, corneal thickness, electroretinography, or histopathologic examination.

Affected females in X-linked congenital stationary night blindness.

Most heterozygous (carrier) females in families with X-linked congenital stationary night blindness are asymptomatic. Several anecdotal cases of manifesting females in X-linked congenital stationary night blindness have been reported, but few clinical details are available. The authors report clinical, electroretinographic, and dark adaptation studies of four affected females from a five-generation family with X-linked congenital stationary night blindness. Each of the manifesting females was the daughter of a different, asymptomatic, carrier mother. None of the 14 daughters of the 9 affected males showed signs or symptoms of congenital stationary night blindness. Uneven X-chromosomal lyonization is the most likely reason for these females manifesting this X-linked disorder.

RESOLUTION OF AN APPARENT CHOROIDAL MELANOMA

A 67-year-old white woman had a lesion that clinically, echographically, and angiographically appeared to be consistent with choroidal melanoma. At follow-up examination 2 months later, the lesion had clinically completely resolved. A limited choroidal hemorrhage simulating a choroidal melanoma is postulated.

Echographic pseudoextension of uveal melanomas

Abstract• Background: Standardized echography is routinely utilized to assess uveal melanomas. Echographic pseudoextension is defined as normal structures mimicking intrascleral or extrascleral extension of tumor on echography. • Methods: The records of 151 consecutive uveal melanoma patients evaluated with standardized echography over a 6-year period (1986–1991) were reviewed to identify those in which pseudoextension or true extension was diagnosed. • Results: Fourteen (9%) cases of pseudoextension were noted, with causes including juxtapapillary tumor location (seven cases), extraocular muscle insertion (five cases), vortex ampullae (one case), and post-brachytherapy changes (one case). Clinical, echographic, and/or histopathologic follow-up confirmed absence of true extension. Six (4%) cases of true extrascleral extension were identified and confirmed histopathologically. • Conclusion: Differentiating extraocular tumor extension from pseudoextension is critical, and use of standardized A-scan and contact B-scan echography is integral in this assessment.

Development and Characterization of a Nonprimate Animal Model of Methanol-Induced Neurotoxicity

Humans and nonhuman primates are uniquely sensitive to the toxic effects of methanol. The toxic syndrome in these species is characterized by formic acidemia, metabolic acidosis and blindness or serious visual impairment. Nonprimate species are normally resistant to the accumulation of formate and associated metabolic and visual toxicity. The authors have developed a nonprimate model of methanol toxicity using rates in which formate oxidation has been selectively inhibited. Methanol-intoxicated rats developed formic acidemia, metabolic acidosis and visual toxicity analogous to the human methanol poisoning syndrome. Visual dysfunction was manifested as reductions in the flash evoked cortical potential and electroretinogram which occurred coincident with blood formate accumulation. Histopathologic studies revealed mitochondrial disruption and vacuolation in the retinal pigment epithelium, photoreceptor inner segments and optic nerve. The establishment of this nonprimate animal model of methanol intoxication will facilitate research into the mechanistic aspects of methanol toxicity as well as the development and testing of treatments for human methanol poisoning.

Pseudophakia for Traumatic Cataracts in Children

PURPOSE The purpose of this prospective study is to evaluate the postoperative visual acuity, refractive error, intraocular pressure, and status of the posterior capsule in children with traumatic cataracts who undergo extracapsular cataract extraction and insertion of a posterior chamber lens. METHODS Extracapsular cataract extraction and primary endocapsular fixation of a posterior chamber lens implant were performed in eight children (age range, 4-17 years) with unilateral traumatic cataracts. RESULTS There were no intraoperative complications, and seven of eight eyes achieved 20/40 or greater spectacle visual acuity during an average follow-up interval of 10 months (range, 5-20 months). The average postoperative spherical equivalent refractive error was +0.33 diopter (D) (range, -2.25 to +2.12 D); the average postoperative anisometropia was approximately 1 D (range, 0-2.25 D). In one patient, a coagulase-negative staphylococcal endophthalmitis developed 10 days after surgery. In three eyes that had opacified posterior capsules, YAG laser capsulotomy was performed. CONCLUSIONS These preliminary results suggest that intraocular lens (IOL) implantation may be a safe and effective method of optical correction for children with traumatic cataracts.