The relationship of corneal epithelial defect size to drug penetration.

OBJECTIVE: To determine the relationship between corneal epithelial defect size and corneal penetration of a triazole antifungal drug in an animal model. METHODS: Corneas of adult rabbits were débrided of epithelium 25%, 50%, 75%, or 100% of surface area; the untreated fellow eye served as a control. Tritiated saperconazole was applied to each cornea every 5 minutes for 1 hour. The animals were killed and the cornea and aqueous of each eye were assayed for radiolabel activity. RESULTS: Removal of 25% of the corneal epithelium produced an increase in corneal saperconazole concentration compared with eyes with intact epithelium. Increasing epithelial defect size from 25% to 50% produced a ninefold increase in mean corneal drug concentration (P = .0001). There was no further increase in corneal drug levels in eyes with 75% or 100% epithelial defects. A similar threshold effect was observed in aqueous drug concentration between 25% and 50% débridement (P = .0001). CONCLUSION: In this experimental model, an apparent threshold was noted between 25% and 50% epithelial defect area, beyond which larger defects did not significantly increase drug penetration into the cornea or aqueous. This may be of clinical benefit in circumstances in which epithelial débridement is considered to enhance drug penetration.

Cellular infiltration of the vitreous in a patient with X-linked immunodeficiency with increased IgM.

We studied visual impairment caused by benign lymphoid infiltration of the vitreous bilaterally, as a complication of a primary immunodeficiency, X-linked immunodeficiency with increased IgM in an 8-year-old boy. Immunophenotyping of a vitreous aspirate showed a mixed cell population, including lymphocytes (T helper, suppressor-cytotoxic T cells, and B cells) and macrophages. Cultures of the vitreous were negative for bacterial or fungal pathogens. The vitreous infiltrates have been resistant to treatment with corticosteroids and cytotoxic agents.

Posterior chamber intraocular lenses after extracapsular cataract extraction in patients with aniridia.

Visual rehabilitation of patients with aniridia and progressive cataract is a challenging clinical problem. Reduced corneal transparency, limitations of iris support, and decreased zonular integrity may make extracapsular cataract surgery difficult. Four patients with familial aniridia had substantial visual improvement after successful extracapsular cataract extraction (ECCE) with implantation of capsular-fixated posterior chamber intraocular lenses (PC IOLs). In one patient, it was combined with trabeculectomy to treat chronic open-angle glaucoma. Posterior chamber IOLs can be safely implanted in the aniridic eye normalities in the anterior segment.

Retinal vascular abnormalities in patients with coarctation of the aorta.

Pulsatile three-dimensional retinal arteriolar tortuosity has been previously reported in about 50% of patients with coarctation of the aorta. In a contemporary series of 20 patients with coarctation of the aorta, none exhibited this characteristic retinal vascular abnormality. Our findings suggest that the retinal vascular abnormalities in patients with coarctation of the aorta represent secondary hemodynamic changes. The prevalence of these abnormalities may be decreasing because of earlier surgical repair of coarctation.

Hereditary lymphedema and distichiasis.

Two patients with lymphedema-distichiasis syndrome illustrate that both Milroy's disease and late-onset hereditary lymphedema are sometimes associated with distichiasis. It is important for ophthalmologists to be aware of the lymphedema-distichiasis syndrome because of its ophthalmic manifestations and the associated systemic abnormalities that can be potentially life threatening.

Retinopathy of prematurity in infants with cyanotic congenital heart disease.

We undertook a study of premature infants with cyanotic congenital heart disease to determine whether these infants develop retinopathy of prematurity despite a persistent hypoxemic state. Using the computerized registry of the neonatal intensive care unit of Vanderbilt University Medical Center, Nashville, Tenn, we identified six premature infants (less than 37 weeks' gestational age, with birth weights of 1100 to 2050 g) with cyanotic congenital heart disease who survived the neonatal period and underwent ophthalmologic evaluation. Review of their charts revealed that three of six infants developed retinopathy of prematurity (two had grade 1 and one had grade 3 disease), but none required treatment. Our data support the findings of other investigators that elevated arterial oxygen tension is not the sole factor leading to the development of retinopathy of prematurity. Premature infants with cyanotic congenital heart disease can develop retinopathy of prematurity despite persistent hypoxemia. Cyanotic premature infants should be screened for retinopathy of prematurity with the same thoroughness as other premature infants.

Anterior segment ischemia in chronic herpes simplex keratouveitis.

Six patients with chronic herpes simplex keratouveitis developed a rapidly progressive ocular inflammation unresponsive to corticosteroid and antiviral therapy. Severe secondary glaucoma unresponsive to maximum medical therapy ensued and was treated by cyclocryotherapy in five patients. Ocular ischemia with secondary corneal and scleral calcification subsequently developed in all six patients. All had also received prolonged topical therapy with topical antiviral agents, corticosteroids, beta adrenergic blockers and epinephrine compounds. Three eyes eventually required enucleation for the relief of pain; one stabilized, and two others became phthisical. One of the phthisical eyes developed a secondary fungal endophthalmitis. Histopathologic examination of the three enucleated globes revealed extensive corneal, scleral and conjunctival calcification, secondary angle closure, iris and ciliary body necrosis, focal choroiditis, retinal necrosis and atrophy. The syndrome recognized in these patients appears to be a rare but devastating complication of herpes simplex keratouveitis, possibly exacerbated by the application of cyclocryotherapy and other factors.

Sterile corneal ulceration after cataract extraction in patients with collagen vascular disease.

We report the occurrence of sterile corneal ulceration in 11 eyes of eight patients with collagen vascular diseases and dry eyes after cataract extraction with intraocular lens implantation. Keratolysis occurred after both extracapsular and intracapsular cataract extraction and appeared unrelated to the type of intraocular lens. Despite aggressive lubrication and other medical treatment, including systemic immunosuppressive agents, penetrating keratoplasty was often required. Although all eyes were saved, visual outcome was usually poor. The histopathologic finding of polymorphonuclear leukocytes localized near the areas of corneal dissolution provides evidence for the role of polymorphonuclear leukocyte-derived collagenase as a contributing factor in the pathogenesis of sterile corneal ulceration in these patients.

Traumatic wound dehiscence in pseudophakia.

In a series of 11 pseudophakic patients (11 eyes) who sustained wound dehiscence as a result of blunt trauma, five intraocular lenses were dislocated, one was fractured, and two were expulsed. Wound rupture occurred from three days to one year after surgery; the most common cause of injury was a fall. Iris prolapse was observed in all patients, with hyphema observed in seven. Vitreous prolapse occurred in four patients, and three patients developed retinal detachment. Six of the 11 patients had a visual acuity of 20/40 or better after repair. The limbal wound of a pseudophakic eye can dehisce as a consequence of blunt trauma long after surgery, and the position of the intraocular lens can be disrupted. Patients undergoing cataract extraction with intraocular lens implantation should be advised about the importance of long-term protective eyewear.

Acanthamoeba keratitis in Tennessee: a growing problem in patients wearing contact lenses.

All physicians evaluating a painful red eye in a contact lens wearer should consider the diagnosis of Acanthamoeba keratitis. Although it remains relatively rare, the incidence of this infection is on the rise. Clues to the correct diagnosis include a corneal abrasion that fails to heal appropriately, pain out of proportion to the clinical findings, and a history of poor contact lens hygiene. Prompt recognition and appropriate ophthalmologic intervention can improve the visual outcome for patients with this devastating corneal infection.

The effect of panretinal photocoagulation on optic nerve cupping.

Panretinal photocoagulation (PRP) can produce damage to all layers of the retina, including the nerve fiber layer. The hypothesis that these changes in the nerve fiber layer may alter the contour of the optic disc and change the cup-to-disc (C/D) ratio was tested. In a masked retrospective study, the authors evaluated the stereoscopic disc photographs of 100 patients with proliferative diabetic retinopathy (PDR) before and 1 year after undergoing PRP. The fellow untreated eyes were used as controls. Neither argon nor xenon PRP produced a significant change in the C/D ratio.

Pharmacologic management of keratomycoses.

Fungal corneal infections can be very difficult to treat. An evolving understanding of the pharmacology of the currently available antifungal agents has led to improved medical treatment of the keratomycoses. The pharmacology, pharmacokinetics, spectrum of activity and toxicity of these agents is reviewed and promising new antifungal compounds and modes of treatment are discussed.

Chorioretinitis in the contralateral eye of a patient with Acanthamoeba keratitis.

Chorioretinitis developed in the right eye of a patient with contact lens-associated Acanthamoeba keratitis in the left eye during an acute exacerbation of the keratitis. This chorioretinitis may have resulted from hematogenous dissemination from his corneal infection.

Corneal toxicity of propamidine.

Two patients with Acanthamoeba keratitis developed a corneal abnormality following prolonged treatment with topical 0.1% [corrected] propamidine isethionate. In both instances, withdrawal of drug therapy resulted in a gradual clearing of the keratopathy, with no permanent sequelae. The changes we observed may be confused with those of active Acanthamoeba infection.