Flow cytometric DNA analysis of corneal epithelium.

We have modified an existing technique in order to perform DNA analysis by flow cytometry (FCM) of corneal epithelium from the mouse, rat, chicken, rabbit, and human. This protocol permitted an investigation of human corneal scrapings from several categories: normal, aphakic bullous keratopathy (ABK), keratoconus (KC), Fuch's dystrophy, edema, epithelial dysplasia, and lipid degeneration. No abnormal characteristic cell-kinetic profile was detected when averaged DNA histograms were compared statistically between the normal and either ABK, KC, edema, or Fuch's dystrophy groups. Abnormal DNA histograms were recorded for cell samples that were taken 1) from three individuals who had epithelial dysplasia and 2) from one individual diagnosed with lipid degeneration. The former condition was characterized by histograms that had a subpopulation of cells with an aneuploid amount of DNA or had higher than normal percentages of cells in the S and G2 + M phases of the cell cycle. Corneal cells from the patient who had lipid degeneration had an abnormally high percentage of cells in the G2 + M phases of the cell cycle. The availability of accurate DNA flow cytometric analysis of corneal epithelium allows further studies on this issue from both experimental and clinical situations.

Prediction of postoperative visual acuity in cataract patients using the Flying Corpuscle Viewer.

One hundred one cataract patients were tested preoperatively for macular function using the Flying Corpuscle Viewer, a portable blue field entoptic device which utilizes the slit lamp as a light source. Preoperative appreciation of the "Flying Leukocyte Corpuscles" (FLC) indicated a high probability of good postoperative visual acuity, while lack of appreciation of the blue field entoptic phenomenon preoperatively had no predictive value for postoperative visual acuity.

Long-term visual acuity results after penetrating and perforating ocular injuries.

Of 33 consecutive patients (30 males and three females, ranging in age from 5 to 48 years) with penetrating ocular injuries, 13 had retained metallic intraocular foreign bodies. The remaining 20 had no retained foreign bodies and their injuries were generally more severe lacerating or double perforating injuries. Magnet extraction was used for foreign body extraction when possible, and pars plana posterior vitrectomy was used only for late complications. The long-term visual acuity results indicated that wound repair, conventional magnet extraction, and removal of traumatic cataract and anterior vitreous blood through a limbal incision is still a viable treatment for many such injuries.

Treatment of Aspergillus fumigatus keratitis in rabbits with oral and topical ketoconazole.

Aspergillus fumigatus keratitis was established in rabbits by intrastromal injection of a suspension containing 5,000 spores. After a 48-hour incubation period, the animals were treated with oral and topical ketoconazole alone and in combination with topical natamycin for five days. Colony counts per cornea were obtained at the conclusion of the treatment period. Based on these colony counts, neither oral nor topical ketoconazole was effective despite moderate in vitro sensitivity of the fungus to ketoconazole. Oral and topical ketoconazole used in conjunction with natamycin, however, appeared to augment sterilization of A. fumigatus in this model of fungal keratitis.

Topical timolol and epinephrine: biochemical actions and interactions in the rabbit eye in vivo.

The effects of topical 0.5% timolol maleate and 1% or 2% levo-epinephrine hydrochloride on aqueous humor cyclic-AMP and intraocular pressure were assessed in 97 normotensive New Zealand white rabbits in vivo. The study was conducted using three experimental protocols: (A) timolol and epinephrine individually, (B) timolol and epinephrine in coadministration, and (C) timolol and epinephrine in crossover, applied either in a single dose, twice a day for two days, and/or twice a day for six days. These studies demonstrated that timolol has complex biochemical actions, one of which is beta-adrenergic antagonism. By itself, timolol had no effect on cyclic-AMP levels. However, when used in both single-dose coadministration and in pretreatment in six-day crossover with epinephrine, it significantly diminished the cyclic-AMP elevation produced by a single dose of epinephrine. In the six-day crossover protocol, pretreatment with timolol also significantly reduced the ocular hypotensive effect of a single dose of epinephrine, thereby correlating biochemical cause with clinical effect. Yet, timolol alone had no ocular hypotensive effect. Therefore, timolol's biochemical actions in this animal model cannot explain its marked clinical efficacy in man, which appears to depend on more complex pharmacologic actions.

Inhibition of secondary cataracts by cryolysis of lens epithelium in rabbits.

In an attempt to inhibit secondary cataract formation by destroying the subcapsular lens epithelium, a defined amount of freeze was applied to the anterior capsule of one eye of 16 New Zealand white rabbits just prior to a planned extracapsular cataract extraction of both eyes using phacofragmentation. The rabbits were sacrificed eight weeks after surgery and the secondary cataracts were dissected from the eyes. The degree of secondary cataract formation was evaluated by two independent observers and grading systems. Overall, 14 of 16 rabbits, or 88%, had a significant (P less than .01) reduction of secondary cataract in the treated eye as compared to the control eye. This study demonstrates that freezing of the subcapsular lens epithelium prior to a planned extracapsular cataract extraction in rabbits can significantly diminish secondary cataract formation. However because of the present difficulty in controlling the extent of the freeze to the surrounding ocular tissues with current cryoprobes, this procedure is not yet applicable in humans.

Phacofragmentation and irrigation.

Phacofragmentation and irrigation is an excellent operation for easy extracapsular removal of cataracts through a small limbal incision for patients without significant nuclear sclerosis. Although the technique can be used in the senile age goup for special situations, it is not recommended as a substitute for the routine intracapsular operation for those patients with moderate to severe nuclear sclerosis. For good, consistent results, patient selection, animal practice, and familiarity with the operating microscope are important.

Acute presumed histoplasmosis of the optic nerve head.

A 38-year-old man from the Ohio Valley area presented to the Ophthalmology Cinic at a west coast hospital (USA) because of sudden loss of the right inferior temporal visual field after severe right frontal headache of several hours' duration. During the following months, diffuse peripapillary atrophy and peripheral punched-out lesions developed. When he had been seen initially, the fundus of the left eye had also revealed extensive, diffuse, peripapillary atrophy and scarring. All laboratory tests were normal except a histoplasmin intradermal skin test. The clinical appearance of both eyes 8 months after the acute episode in the right eye supports the diagnosis of presumed ocular histoplasmosis.

Septo-optic dysplasia associated with see-saw nystagmus.

Septo-optic dysplasia is a syndrome of midline abnormalities of the central nervous system resulting in absence of the septum pellucidum and dysplasia of the optic chiasm or optic nerves. The characteristic fundus findings of small, dysplastic discs and defects in the nerve fiber layer enable the clinician to predict this syndrome prior to contrast studies. An unsual form of nystagmus, see-saw nystagmus, was associated with septo-optic dysplasia in this case report.