The histopathology of filamentary keratitis.

Filamentary keratitis is characterized by the presence of fine filaments of epithelium and mucus that are attached to the cornea. The exact pathogenesis of this entity has remained unclear. One reason has been the lack of pathologic specimens of corneas from patients with filamentary keratitis. We examined the corneas of a patient who had died while suffering from filamentary keratitis. Scattered groups of inflammatory cells and fibroblasts were present just below the basal epithelium. It seemed that these cells had disrupted the epithelial basement membrane and Bowman's layer. To our knowledge, this is the first postmortem analysis of a cornea in a patient with acute filamentary keratitis. These findings support the theory that filamentary keratitis results from damage to the basal epithelial cells, epithelial basement membrane, or both.

Simultaneous perfusion of air and irrigating solution in the management of traumatic posterior segment injuries.

A technique to perfuse air and infusion fluid simultaneously in the management of severe posterior segment injuries has been developed. The technique requires air infusion through an infusion cannula while fluid is introduced and aspirated by a full-function vitrectomy instrument. This technique can be used in the primary procedure, or in secondary procedures in which the retina has been reattached by a fluid-gas exchange postoperatively.

Reversible monocular cataract simulating amaurosis fugax.

In a patient having brittle, juvenile-onset diabetes, transient monocular visual loss occurred repeatedly whenever there were wide fluctuations in serum glucose. Amaurosis fugax was suspected. The visual loss differed, however, in that it persisted over a period of hours to several days. Direct observation eventually revealed that the relatively sudden change in vision of one eye was associated with opacification of the lens and was not accompanied by an afferent pupillary defect. Presumably, a hyperosmotic gradient had developed with the accumulation of glucose and sorbitol within the lens. Water was drawn inward, altering the composition of the lens fibers and thereby lowering the refractive index, forming a reversible cataract. Hypoglycemia is also hypothesized to have played a role in the formation of a higher osmotic gradient. The unilaterality of the cataract is attributed to variation in the permeability of asymmetric posterior subcapsular cataracts.

Iatrogenic choroidal neovascularization in sickle cell retinopathy.

Fifteen patients (16 eyes) with proliferative sickle retinopathy treated with argon or xenon arc feeder vessel photocoagulation had chorioretinal (CRN) or choriovitreal (CVN) neovascularization develop. These patients were followed from 2 1/2 to 11 1/2 years with a mean follow-up of 6 years and 8 months. Clinically important late complications of the choroidal neovascularization included vitreous hemorrhage (in three of eight patients with CVN). However, in only two of these three eyes was there any drop in vision related to residual vitreous hemorrhage, and this was limited to loss of only one line of Snellen visual acuity. Therefore, treatment is not usually recommended if CRN or CVN develops after intense photocoagulation. Vitreous fluorophotometry was performed on these patients to examine the breakdown of the blood-retinal barrier. This gave a quantitative measure of fluorescein leakage not obtained with fluorescein angiography. Midvitreous measurements, which are more representative of these peripherally located proliferative lesions than are pre-retinal measurements, suggest that vitreous fluorophotometry may be helpful in differentiating the higher leakage of CVN from the CRN.

Alteration of the blood-retinal barrier and vitreous in sickle cell retinopathy.

Nineteen eyes with background sickle cell retinopathy, eleven from patients with SC disease, eight from patients with SS disease, and twelve eyes with proliferative sickle cell retinopathy were examined by direct and indirect ophthalmoscopy, slit-lamp, fluorescein angiography and vitreous fluorophotometry. Calculation of the alteration of the blood-retinal barrier (BRB) and estimation of the diffusion coefficients of fluorescein in the vitreous were performed by fluorophotometry. In background sickle cell retinopathy, the results show a normally functioning BRB in the posterior pole. Abnormally increased fluorescence values to the mid-vitreous (peripheral leakage) were found only in 3 of these 19 eyes, at the two-hour examination (all SC patients). Similarly, mid-vitreous fluorescence values at the two-hour examination were 4.19 +/- 1.52 ng/ml in eyes of patients with SC disease, compared with 2.65 +/- 0.56 ng/ml in eyes of patients with SS disease. All eyes with background sickle cell retinopathy, except one, showed values for the coefficient of diffusion of fluorescein within normal limits, indicating normal vitreous gel structure. In proliferative retinopathy, the mid-vitreous fluorophotometry readings were abnormally increased, correlating well with the extent of the peripheral angiographic changes (neovascularization). The coefficient of diffusion of fluorescein in the vitreous was generally increased in the eyes with proliferative retinopathy (15.0 +/- 8.4 X 10(-4) cm2/min) in comparison with a mean value of 5.4 +/- 1.4 X 10(-4) cm2/min in the eyes with background sickle cell retinopathy, suggesting an alteration of the vitreous structure eyes with proliferative retinopathy. Fluorophotometry is considered a useful tool to follow patients with sickle cell retinopathy by quantitating peripheral retinal vascular leakage.