George A. Stern

Serious Corneal Complications of Glaucoma Filtering Surgery With Postoperative 5-Fluorouracil

We studied four patients who, having received postoperative 5-fluorouracil after glaucoma filtering operations, developed serious corneal complications. All four patients had preexisting corneal abnormalities including keratoconjunctivitis sicca, exposure keratopathy, and bullous keratopathy. All of the patients developed epithelial defects in the postoperative period. The complications included bacterial corneal ulceration (two patients), sterile corneal ulceration and corneal perforation (one patient), and a keratinized corneal plaque with underlying sterile stromal infiltrate (one patient). The use of 5-fluorouracil, which is an antimetabolite with considerable corneal epithelial toxicity, after glaucoma filtering surgery frequently causes corneal epithelial defects that may lead to secondary complications. Patients receiving this drug should have their corneal status closely monitored. In patients with corneal epithelial disease, 5-fluorouracil should be used with caution.

Use of Corticosteroids in Combination with Antimicrobial Drugs in the Treatment of Infectious Corneal Disease

The use of corticosteroids in the management of infectious eye disease is controversial. In this study, the authors attempt to analyze the goals and risks of the use of corticosteroids in the treatment of various forms of infectious keratitis with reference to generally recognized principles for the treatment of infectious diseases. Existing clinical and research data are reviewed in this context to make appropriate recommendations for the use of corticosteroids in the treatment of bacterial, fungal, and acanthamoeba keratitis. The authors conclude that corticosteroids are definitely contraindicated in the treatment of fungal keratitis, and relatively contraindicated in the treatment of Acanthamoeba keratitis. Topical corticosteroid therapy may have a role in the treatment of bacterial keratitis if appropriate guidelines are followed.

CORRELATION BETWEEN PTERYGIUM SIZE AND INDUCED CORNEAL ASTIGMATISM

Purpose Before invasion of the visual axis, pterygia typically induce with-the-rule astigmatism, which can be visually significant. In this study, we attempted to assess the quantitative relation between pterygium size and induced corneal astigmatism using corneal topography and digital imaging. Methods Thirty-three eyes of 25 patients with primary pterygia were evaluated using corneal topography (TMS), slit-lamp photography, and digital imaging to correlate parameters of pterygium size with induced corneal astigmatism at the 3- and 6-mm optical zones. Results Pterygia induce asymmetric with-the-rule astigmatism. Lesions extending >45% of the corneal radius or within 3.2 mm of the visual axis produce increasing degrees of induced astigmatism. Conclusion Once pterygia reach a critical size, they induce visually significant central with-the-rule astigmatic changes that may not be apparent by subjective refraction. This finding helps to identify those patients who may benefit from surgical intervention.

Indications for and results of intraocular lens explantation

ABSTRACT We reviewed the medical records of 97 patients who had 101 consecutive intraocular lens (IOL) explantation procedures, with or without exchange, at the University of Florida Eye Center from January 1, 1983, to December 31, 1987. The majority of the removed IOLs were anterior chamber styles (53.9%), followed by iris‐fixated lenses (33.7%). The most common indications for surgery included pseudophakic bullous keratopathy (PBK)—69%, uveitisglaucoma‐hyphema (UGH) syndrome—9%, and 101, instability—7%. The best visual outcome was seen in patients with IOL instability; 50% achieved 20/40 or better visual acuity. Forty one percent of patients with PBK, who had IOL explantation/exchange combined with penetrating keratoplasty, achieved 20/40 or better visual acuity. The poorest visual outcome was seen in patients with the UGH syndrome; 83% had a final acuity of 20/200 or worse. However, these patients achieved resolution of their pain and inflammation and better control of their intraocular pressure as a result of the surgery. Complications leading to IOL explantation tended to occur months to years after the original surgery in patients with closed‐loop, semi‐flexible anterior chamber lenses and iris‐fixated lenses. Posterior chamber lenses were most often removed because of complications unrelated to the implant.

The Treatment of Postoperative Endophthalmitis: Results of Differing Approaches to Treatment

The authors treated 26 patients with postoperative endophthalmitis over a 4-year period, between 1983 and 1986. Nineteen patients were culture-positive and seven were culture-negative. All patients received intravitreal antibiotics as part of their treatment regimen. Culture-negative patients generally responded well to a single intravitreal antibiotic injection. Five of seven (71.4%) culture-positive patients who were treated with a single intravitreal antibiotic injection and no vitrectomy suffered either a recurrence of their infection or did not respond to treatment. Four of five patients who received a vitrectomy in addition to a single intravitreal antibiotic injection were cured of their infections; the one patient who received repeated intravitreal antibiotic injections alone and all six patients who received repeated intravitreal antibiotic injections in combination with vitrectomy were cured of their infections. Although the intravitreal injection of antibiotics provides an extremely high initial level of antibiotics inside the eye, a single intravitreal antibiotic injection may only partially treat bacterial endophthalmitis. In culture-negative cases, a single intravitreal injection of antibiotics appears to be sufficient treatment. In culture-positive cases, a higher cure rate is achieved with an aggressive approach which includes the use of repeated intravitreal antibiotic injections and/or vitrectomy.

Effect of pterygium excision on induced corneal topographic abnormalities.

Purpose To determine the effect of successful pterygium surgery on astigmatism and other corneal topographic indices. Methods Preoperative and postoperative refraction and corneal-topography analysis were performed on 16 consecutive eyes of 12 patients who underwent successful pterygium surgery, with statistical comparison of the pre- and postoperative visual acuity, refractive astigmatism, topographic astigmatism, Surface-Regularity Index, and Surface-Asymmetry Index. Results Successful pterygium surgery caused statistically significant improvements in visual acuity, refractive and topographic astigmatism, the Surface-Regularity Index, and the surface asymmetry index. Conclusion Corneal-topography analysis is an important component of the evaluation of patients with pterygium, revealing significant abnormalities that are improved by successful removal of the pterygium.

The Pathogenesis of Contact Lens-associated Pseudomonas aeruginosa Corneal Ulceration I. The Effect of Contact Lens Coatings on Adherence of Pseudomonas aeruginosa to Soft Contact Lenses

The adherence of a strain of Pseudomonas aeruginosa to hydrophilic contact lenses was quantitatively determined using scanning electron microscopy. Soft contact lenses were incubated for 72 h in either phosphate-buffered saline (PBS), a 500-μg/ml solution of human serum albumin (HSA), a 500-μg/ml solution of bovine submaxillary gland mucin, or a solution containing 500 μg/ml of both HSA and mucin. Lenses were then incubated for one hour in a 107-ml suspension of P. aeruginosa. The number of adherent bacteria per field at × 8,000 magnification was determined. Only 1.96 ± 2.52 bacteria/field were found on lenses incubated in saline, whereas 5.23 ± 5.30 bacteria/ field were adherent to lenses incubated in HSA, 23.42 ± 31.01 to lenses incubated in mucin, and 26.76 ± 35.12 to lenses incubated in a solution containing both HSA and mucin. Contact lens coatings, especially mucin, facilitate the adherence off. aeruginosa to soft contact lenses and may therefore play a role in the pathogenesis of contact lens-associated pseudomonal keratitis.

Recurrent postoperative endophthalmitis.

We treated five patients for postoperative endophthalmitis who demonstrated an initially good response to intravitreal management of their infection and then suffered a later recurrence. Four of the five patients received a single intravitreal injection of antibiotics as the only intravitreal therapy, and the fifth patient received a single antibiotic injection in addition to a partial vitrectomy. All recurrent infections occurred between 10 and 21 days after the original intravitreal injection of antibiotics. At the time of the recurrence, all five patients remained culture positive with the same organism that was initially isolated. The bacterial species isolated were S. epidermidis, group D streptococcus, P. acnes, P. mirabilis, and P. aeruginosa. All patients were ultimately sterilized with repeated intravitreal injections of antibiotics, vitrectomy, and/or intraocular lens removal. Factors that were related to recurrent infection were marginal susceptibility of the organism to the originally injected antibiotics, infection with a slowly replicating organism, and infection with a gram-negative bacillus. A single intravitreal injection of antibiotics may only partially treat bacterial endophthalmitis. Patients should be observed for at least 3 weeks following treatment of endophthalmitis for recurrence of their infection, and aggressive management, including vitrectomy and repeated intravitreal injections of antibiotics, should be used to treat recurrent infections.

Corneal Anesthetic Abuse and Candida Keratitis

PURPOSE Topical corneal anesthetic abuse is a self-inflicted injury, causing profound corneal morbidity. Superimposed infection is an important complicating factor. The authors report four patients with confirmed topical anesthetic abuse of the cornea, in whom Candida keratitis developed. METHODS A retrospective review of the medical records of four patients with confirmed topical corneal anesthetic abuse and fungal keratitis. RESULTS A 21-year-old woman, two 28-year-old women, and a 35-year-old man were included in the study. All these patients sustained a corneal injury, prompting the chronic use of topical anesthetics (0.5% proparacaine hydrochloride in 3 patients, and 0.5% tetracaine hydrochloride and 0.4% benoxinate hydrochloride in the other). Corneal findings included epithelial defects in all patients, focal infiltrate in one patient, and ring-shaped stromal infiltrate in three patients. Topical anesthetic was discontinued, all patients initially were treated empirically with antibacterial agents, and three patients received topical corticosteroids. Subsequent corneal cultures grew Candida spp, Candida albicans specifically in three patients, and local and systemic antifungal therapy was started. Corneas in two patients re-epithelialized; a conjunctival flap was performed on another patient with a descemetocele; and the remaining patient was lost to follow-up, although repeat fungal cultures yielded no growth. CONCLUSIONS Corneal superinfection with Candida may occur during topical anesthetic abuse. Therapy includes discontinuation of the anesthetic and institution of antifungal therapy.

Bacterial Keratitis Associated with Vernal Keratoconjunctivitis

We cared for two patients with longstanding vernal keratoconjunctivitis who had bacterial corneal ulcers in each eye. Both patients were young, black, and had histories of atopy. The patients came for treatment with acute symptoms of pain, redness, and reduced vision in the affected eye. On examination in each case we found an epithelial defect associated with dense stromal infiltration, a calcific plaque in the bed of the ulcer, and a severe anterior chamber reaction, including a hypopyon in two cases. Cultures of corneal scrapings from all four eyes were positive for Staphylococcus aureus, and three of the four infections were polymicrobial. All four eyes responded rapidly to intensive topical antibiotic therapy, debridement of the calcific plaque, and subsequent treatment with topical corticosteroids and/or cromolyn sodium. Bacterial keratitis can occur in patients with vernal keratoconjunctivitis, especially those with vernal corneal ulcers. The abnormalities of ocular immune mechanisms found in patients with vernal keratoconjunctivitis may predispose them to bacterial keratitis.