Resistance of wild Norway rats in North Carolina to warfarin rodenticide.

Reports concerning the ineffectiveness of warfarin rodenticide, used at farms and stores in a rural area about 8 kilometers in diameter near Raleigh, North Carolina, prompted subsequent laboratory testing. All of the 25 Norway rats trapped from the area survived 6 days of no-choice feeding of bait containing 0.025 percent (by weight) warfarin.

Cryotherapy for precancerous melanosis (atypical melanocytic hyperplasia) of the conjunctiva.

Two patients with progressive, diffuse precancerous melanosis (intraepithelial atypical melanocytic hyperplasia or melanocytic dysplasia) of the conjunctiva were treated with cryotherapy. In one patient, the contiguous cutaneous portions of both eyelids were involved and received the same therapy; the extensive disease of the patient was managed by two cryotherapy sessions during a period of 21/2 months. The melanocytic process in both patients showed a good response to this therapy, which resulted in a slough of the superficial conjunctiva with reepithelialization from adjacent areas. Neither patients has shown recurrent disease in more than seven months of follow-up, although one patient had incomplete regression of the melanocytic condition in the perilimbal region, which was subsequently treated by an excisional biopsy. Serious complications occurred in one patient who had corneal and lenticular opacities; this patient had severe extensive disease for which exenteration was considered the only feasible alternative therapy to control the melanocytic proliferation disorder adequately. Less severe complications also developed, including trichiasis, ptosis, transient hypotony, and macular edema. In this article, we discuss the clinical and histologic features of acquired pigmentations of the conjunctiva, the criteria for their management, and the approaches to minimize the complications that we have encountered with cryotherapy.

Differentiating conjunctivitis of diverse origins.

While symptoms can be very distressing, patients with conjunctivitis general maintain good vision and recover completely without permanent sequelae. The great majority of cases of conjunctivitis are infectious or allergic in origin. Seen with increasing frequency are external eye diseases related to contact lens wear or prolonged use of ophthalmic medications. The various forms of conjunctivitis are often not associated with pathognomonic features. A thorough history and ophthalmic examination often permit a presumptive diagnosis and initiation of empiric therapy. For example, a chronic bilateral conjunctivitis, characterized by itching and papillary hypertrophy, suggests an ocular allergy, most frequently the result of exposure to airborne allergens. However, a number of causes, including infections and hypersensitivity reactions, have the potential to threaten vision or produce marked conjunctival scarring which must be identified by the use of appropriate laboratory techniques, followed by specific therapy. Most bacterial and viral conjunctivitis are self-limited, but antimicrobial therapy for the former is advocated to shorten the course, improve patient comfort, prevent recurrence, avoid complications and limit spread to other individuals.

A congenital ichthyosiform syndrome with deafness and keratitis.

This is a report on two children with a syndrome characterized by an extensive congenital ichthyosiform eruption, neurosensory deafness, hypotrichosis, partial anhidrosis, and vascularization of the cornea. The facial involvement is distinctive. Other features are dystrophy of the nails and tight heel cords. Both children are of normal intelligence. The inheritance pattern is unknown.

Pseudomonas aeruginosa scleritis.

In two patients Pseudomonas aeruginosa scleral infection led to ocular perforation. In one patient, a scleral abscess was identified anteriorly. A scleral perforation occurred at a more posterior focus, but the eye was salvaged with minimal residual visual function. In the other patient, perforation at the corneoscleral limbus occurred after initial corneal improvement with antibiotic therapy; histopathologic examination of the enucleated globe disclosed an abscess extending from the corneoscleral limbus to the equator superiorly.

Excimer laser photorefractive keratectomy for low hyperopia: safety and efficacy.

PURPOSE: To assess the safety and efficacy of photorefractive keratectomy (PRK) to correct low hyperopia. SETTING: University of Ottawa Eye Institute, Ottawa General Hospital, Ontario, Canada. METHODS: Twenty-five eyes with refractions of +1.00 to +4.00 diopters (D) and cylinder of 1.00 D or less were treated for hyperopia with the VISX Star excimer laser system using a refined ablation architecture. Thorough visual assessments were performed preoperatively (baseline) and 1, 3, and 6 months postoperatively. Complications were recorded and the level of patient satisfaction was noted. RESULTS: Mean spherical equivalent at 6 months was +0.27 D +/- 0.55 (SD), which was an 89% reduction over baseline. Eighty-four percent of patients gained two to seven lines of near uncorrected visual acuity (UCVA) and 1 patient (4%) lost more than one line. Eight percent achieved 20/25 or better UCVA. Approximately half realized their preoperative distance best corrected visual acuity (BCVA) by 1 month. By the end of the study, all patients had improved, achieved, or were within one line of their baseline distance BCVA. There were some slight reductions in lower contrast acuity at 6 months, although dim lighting conditions did not further reduce these acuities. Most patients had no clinically meaningful change in cylinder. The most common complications included early, transient corneal surface irregularities and visual symptoms and trace haze (grade < or = 0.5) in 14 of 23 patients at 6 months. All but 1 patient expressed a high degree of satisfaction. CONCLUSIONS: These results support the hypothesis that PRK shows great promise as a safe and effective treatment for low hyperopia. There were no significant complications and no decentered ablations. The slight regression occurred with or without the presence of trace haze. Overall, refractive stability was encouraging, although longer follow-up is needed.

Evaluation of current techniques of corneal epithelial removal in hyperopic photorefractive keratectomy.

PURPOSE: To determine the efficacy of 3 current methods used to remove corneal epithelium prior to photorefractive correction of hyperopia and to compare clinical data in patients who had rotary brush or blunt scrape epithelial removal in the treatment of hyperopic photorefractive keratectomy (PRK). SETTING: University of Ottawa Eye Institute, Ottawa General Hospital, Ottawa, Ontario, Canada. METHODS: The epithelium from human eye-bank eyes was removed using a Paton spatula, 15% alcohol, and the Amoils rotating plastic brush. The effects were examined by scanning and transmission electron microscopy. Twelve month postoperative data were obtained on 25 eyes with refractions of +1.00 to +4.00 diopters (D) that had been treated for hyperopia with the VISX Star excimer laser, using blunt scrape or the rotary brush to remove the corneal epithelium. RESULTS: All 3 methods effectively removed corneal epithelium. The Paton spatula, however, left small nicks in Bowman's layer. Both the rotating brush and alcohol debridement left Bowman's layer intact. Alcohol treatment required follow-up epithelial debris removal, while brushing left minimal amounts of debris. There was a strong trend toward rapid epithelial healing in the brushed corneas compared with the scraped ones, but this was not statistically significant. Clinically, at 12 months postoperatively, brushed corneas showed a trend toward more superior outcomes than scraped corneas in actual refractive outcome, uncorrected visual acuity (UCVA), lines of UCVA gained, and predictability of the desired outcomes. However, only the outcome in UCVA of 20/40 or better and the decreased incidence of haze in the brushed corneas over scraped ones were statistically significant. CONCLUSIONS: Both alcohol and the rotating brush provide a quick, effective means of removing the corneal epithelium with minimal risk of damage to Bowman's layer. In our experience, the brush technique was as effective as and possibly superior to the blunt scrape for epithelial removal in hyperopic PRK.

Changes in measured intraocular pressure after hyperopic photorefractive keratectomy.

PURPOSE: To investigate the effect of hyperopic photorefractive keratectomy (PRK) on intraocular pressure (IOP) measurements. SETTING: University of Ottawa Eye Institute, Ottawa Hospital, Ottawa, Canada. METHODS: In this retrospective cohort study, IOP and central corneal thickness (CCT) were measured preoperatively and at 1, 2, 3, 6, 12, 18, and 24 months in 191 eyes that had hyperopic PRK with the VISX Star excimer laser. All corrections applied were between +1.00 and +6.50 diopters (D) of sphere and less than 3.75 D of cylinder. RESULTS: At all postoperative examinations, the mean IOP in the hyperopic PRK group was 1.0 to 1.8 mm Hg lower than the preoperative IOP (P <.001). A large range of IOP changes was found across the population; eg, at 6 months, 49% of the eyes had a change in IOP from baseline of at least +/-3 mm Hg. A mean reduction of 19 microm of CCT was found with pachymetry after surgery (P < .001). The change in IOP readings postoperatively was not correlated with age, sex, keratometric readings, or applied correction. Changes in IOP were strongly correlated with preoperative IOP at all time points and with preoperative CCT at 18 and 24 months (P < .001). After hyperopic PRK, the measured IOP was more likely to increase in patients with preoperative IOPs less than 14.5 mm Hg and more likely to decrease in patients with preoperative IOPs above 14.5 mm Hg. CONCLUSION: Changes in IOP after hyperopic PRK were similar to changes after myopic PRK, despite only minimal changes in the CCT. This suggests that hyperopic PRK results in biomechanical effects that modify the elastic properties of the cornea beyond the changes in rigidity expected from central corneal thinning. There was a strong negative correlation between the measured preoperative IOP and the change in IOP postoperatively that was likely the result of regression of the mean effect.

Marginal infiltrative ulcerative keratitis secondary to Churg-Strauss syndrome: a case report.

PURPOSE: To describe a patient with keratitis associated with Churg-Strauss syndrome. METHODS: A 44-year-old lady with known Churg-Strauss syndrome was examined with marginal infiltrative ulcerative keratitis. RESULTS: Autoimmune disorders with systemic vasculitis are a major cause of marginal keratitis, and in this patient, the diagnosis of Churg-Strauss was confirmed clinically and pathologically. CONCLUSIONS: Churg-Strauss syndrome should be considered in the differential diagnosis of marginal keratitis.

Postoperative irradiation following immediate breast reconstruction using a temporary tissue expander.

Ten consecutive patients at Howard University Hospital underwent modified radical mastectomy with immediate breast reconstruction using a temporary tissue expander. Postoperative irradiation was delivered to the breast mound encompassing the tissue expander. The effects of expansion on the delivery of postoperative irradiation was assessed. Dosimetric measurements with thermoluminescent dosimeters revealed that the saline-filled expander attenuated the photon beam 3% less than tissue-equivalent material of equal volume. This dose variation was negligible, so no adjustments were made. Postoperative treatment consisted of 5040 cGy to 5220 cGy delivered in 5 to 10 weeks using 4 mV photon tangentials. Cosmesis was assessed over a 2-year period. Six patients completed reconstruction and irradiation without complications. Cosmesis was good in five and fair in one. One patient developed a moist reaction secondary to postoperative irradiation; however, final cosmesis was good. Three patients developed complications leading to the loss of the reconstructed breast. Successful final reconstruction can be achieved with careful patient selection and close follow-up by the plastic surgeon and radiation oncologist.

Pars plana vitrectomy in the management of vitreous touch syndrome.

The management of three patients with aphakic bullous keratopathy by means of pars plana vitrectomy is described. The patients had previously undergone uneventful intracapsular cataract extraction with intact vitreous face. Eventual herniation of the vitreous into the anterior chamber with resultant corneal endothelial touch caused the corneal edema in all three cases. Pars plana vitrectomy resulted in resolution of photophobia and irritation. The visual acuity improved from 20/200, 20/200 and 20/70 to 20/70, 20/60 and 20/40 respectively. The central cornea was cleared of edema in all three cases. The final vision was limited in two of the patients by the persistence of preoperative cystoid macular edema. Pars plana vitrectomy may be used in the management of selected cases of aphakic bullous keratopathy from vitreous touch.

Laser therapy of conjunctival papillomas.

Carbon dioxide (CO2) laser therapy was successfully used in the treatment of recurrent conjunctival papillomas in a 40-year-old man. Surgical excision, cryotherapy and immunotherapy with transfer factor and dinitrochlorobenzene had all been unsuccessful in eradicating the lesions. CO2 laser therapy should be considered as an alternative treatment for conjunctival papillomas refractory to other forms of therapy.

Preventing transmission of human immunodeficiency virus in ophthalmologic practice.

The risk of acquiring HIV infection during an ophthalmologic examination appears to be small but theoretically present. Since it is not always possible to ascertain the presence of HIV infection and because of the grave consequences of infection, all patients must be considered potential carriers. Appropriate preventive measures are imperative. Fortunately, HIV is easily eradicated from the environment. Routine handwashing and cleansing of equipment are normally sufficient to prevent its spread. The fear of AIDS effectively reminds us to adhere to high standards of infection control. This has the added benefit of protecting both physician and patient from other, less lethal but more infective conditions.

Intraocular penetration of netilmicin.

The intraocular penetration of the aminoglycoside netilmicin following intramuscular and subconjunctival injection was studied in 102 patients undergoing elective cataract surgery. Those who received either a single 1.5-mg/kg intramuscular injection or two 1.5-mg/kg injections 6 hours apart subsequently had therapeutic serum levels but aqueous levels of less than 2.4 micrograms/mL. Those who received a subconjunctival injection of either 12.5 or 25 mg of netilmicin subsequently had aqueous levels of up to 36 or 85.6 micrograms/mL; therapeutic levels in the anterior chamber persisted for 7 to 9 hours, with higher levels following the 25-mg injection. Despite wide variation in the aqueous levels following subconjunctival injection the ocular penetration of netilmicin was comparable to that reported for other aminoglycosides. No major complications were associated with the use of this antibiotic by either route.

Schnyder's crystalline corneal dystrophy in association with hyperlipoproteinemia: histopathological and ultrastructural findings.

A 61-year-old man with Schnyder's crystalline corneal dystrophy showed a slight reduction in vision during 16 years of observation. Plasma lipoprotein analysis done 10 years after presentation showed type IIA hyperlipoproteinemia, which was also detected in one of four siblings examined, none of whom showed the characteristic corneal dystrophy. Electron microscopic studies on corneal biopsy specimens from the patient showed abundant crystalline material and vacuoles predominantly in the superficial corneal stroma, with occasional keratocytes and rare basal epithelial cells containing laminated structures. The findings of a focal continuity between the trilaminar membrane around some of the stromal vacuoles and the plasmalemma of the keratocytes as well as dissolution of the plasmalemma in other keratocytes are consistent with the hypothesis of a local cellular role in the development of this corneal disorder.

Ocular complications of a topical methylene blue-vasoconstrictor-anesthetic preparation.

We describe six patients who demonstrated a spectrum of adverse ocular reactions following the use of a nonprescription topical medication composed of methylene blue, naphazoline hydrochloride or nitrate, and amylocaine hydrochloride. This preparation has been commonly sold in Quebec and France for various complaints of ocular discomfort and redness. The ocular complications included asymptomatic blue discoloration of the conjunctiva, follicular and papillary conjunctivitis and varying degrees of cicatrization of the conjunctiva and cornea. The most severe reaction, progressive bilateral ocular pseudopemphigoid, occurred in a 73-year-old woman, presumably due to at least one of the ingredients of this medication.

Cataract extraction in uveitis: comparison of aphakia and posterior chamber lens implantation.

We reviewed the charts of 39 patients (45 eyes) with uveitis who underwent cataract extraction (intracapsular or extracapsular) with or without implantation of a posterior chamber intraocular lens (IOL) at the Royal Victoria Hospital, Montreal, between 1981 and 1990. The nine eyes with Fuchs' iridocyclitis in which an IOL was implanted had good visual results and few postoperative complications. The 18 eyes with uveitis other than Fuchs' iridocyclitis that received an IOL did not show a greater risk of postoperative complications than those left aphakic (n = 17), and the postoperative visual acuity was comparable to that of the aphakic eyes. Although the numbers are small, we conclude that the presence of uveitis does not automatically exclude posterior chamber pseudophakia.

The TRH test: its value in the diagnosis of Graves' ophthalmopathy.

When a goiter or hyperthyroidism is absent, the diagnosis of ophthalmic Graves' disease is often difficult. We evaluated the thyrotropin (TSH) response to intravenously administered thyrotropin-releasing hormone (TRH) in fourteen patients presenting with proptosis or lid retraction. All of them had normal results with routine thyroid function tests and in most a T3 suppression test and orbital ultrasonography were performed. We found an absent or impaired response to TRH in the patients with Graves' ophthalmopathy which correlates well with their having a non-suppressible thyroid gland. Patients with orbital tumours, pseudotumours or congenital lid retraction responded normally to TRH. The TRH test was easier and as reliable as the T3 suppression test in the investigation of a patient with suspected Graves' disease.

Factors affecting the successful use of low-vision aids.

Telephone interviews were conducted with 100 partially sighted patients who had been using low-vision aids for at least 6 months. Only "near-vision" aids were examined. The patients were asked how often they used the aid(s), how satisfied they were with it and whether they had any specific complaints about it. There were no differences in the responses between head-borne and hand-held optical aids. The preferred range of dioptric power was 11 to 20 D.

Canadian ophthalmologists and low vision: a national survey.

It is estimated that by the year 2000 there will be a 36% increase in the number of people over 65 years of age compared with the number in 1977. Since visual impairment in developed countries is largely age related, the number of people who require low-vision services is rapidly increasing. A questionnaire survey was carried out to assess the extent of provision of low-vision services by ophthalmologists in Canada; 119 physicians (13%) responded. The results show that few ophthalmologists provide low-vision care. This situation warrants immediate attention.