Charles W. Flowers

The Role of Smears, Cultures, and Antibiotic Sensitivity Testing in the Management of Suspected Infectious Keratitis

PURPOSE To examine the role of routine smears, cultures, and antibiotic sensitivity testing in the treatment of suspected infectious keratitis. METHODS A retrospective chart and laboratory data review was performed for 81 consecutive patients seen in the Los Angeles County/University of Southern California Department of Ophthalmology between June 1991 and December 1993 with a primary diagnosis of community-acquired infectious keratitis. No patients were treated with antibiotics before evaluation in the authors department, and all underwent corneal scrapings for gram-stain and bacterial, fungal, and mycobacterium cultures. Ulcers were classified as moderate or severe. All initially were treated as inpatients with a regimen including fortified cefazolin and a fortified aminoglycoside. RESULTS Of 81 patients, 74 ulcers were either culture- negative (n=18) or grew bacteria (n=56). Fungal infection was suggested in seven patients. Of the nonfungal ulcers, 33 were classified as moderate, and 41 as severe; all moderate ulcers improved without requiring a modification in antibiotic treatment, whereas 3 severe ulcers required a change in treatment. CONCLUSION Most community-acquired bacterial ulcers resolve with broad spectrum empiric therapy. Alternatives to universal culture and sensitivity testing that might be considered include selectively performing cultures for more severe or suspected non-bacterial ulcers or routinely obtaining cultures in all cases, but pursuing identification and sensitivity studies only when those data are required for therapy modification.

The importance of initial management in the treatment of severe infectious corneal ulcers

PURPOSE To identify factors that influence the outcome of patients with severe infectious corneal ulcers. METHOD A retrospective review was performed of the hospital records of all such patients admitted to the Doheny Eye Hospital during a 30 month period. Outcome variables examined were change in visual acuity, duration of hospitalization, hospital charges, and percentage of patients who required penetrating keratoplasty. RESULTS Sixty-two ulcers were included. An organism was identified and antibiotic sensitivities established in 52 patients (84%). Inpatient therapy involved a combination of fortified aminoglycoside and cephalosporin antibiotics in 39 patients (63%) and was found to be appropriate on the basis of sensitivity studies in 49 (94%) of 52 patients. Inappropriate initial treatment was related to increased hospital charge (P = 0.024) as well as increased risk of penetrating keratoplasty (P = 0.001). CONCLUSIONS Appropriate initial therapy is most critical in the course of serious corneal ulcers, and aggressive, broad-spectrum antibiotic coverage is advocated.

Demographic and clinical characteristics of patients with diabetes presenting to an urban public hospital ophthalmology clinic

OBJECTIVE This study aims to describe the clinical and sociodemographic characteristics of patients with diabetes who are newly presenting to an inner city public hospital eye clinic. This study also aims to determine the prevalence and severity of ocular morbidity in this population at time presentation and to assess the adequacy of the ophthalmic surveillance to which this population was exposed before presentation. DESIGN A clinic-based, cross-sectional study. PARTICIPANTS A total of 118 consecutive patients with diabetes participated. METHOD During a 2-month interval, all patients with diabetes newly presenting to the Los Angeles County King-Drew Medical Center eye clinic were recruited who were at risk for diabetic eye complications according to American Diabetes Association criteria. Each patient underwent a standardized interviewer-administered questionnaire and a comprehensive ophthalmic examination. RESULTS Of the 118 patients, 65 (55%) were Hispanic and 51 (43%) were African American. Forty-six percent had a grade school education or less, 91% were unemployed, and 64% had no health insurance. Type two diabetes was predominant (91%), including 24 (22%) of new onset. Thirty-six patients with diabetes (31%) reported duration of diabetes greater than 10 years at time of presentation. At time of presentation, 62% had clinically apparent ophthalmic disease, whereas 40% had advanced ocular disease, including 6.8% of the sample that were legally blind. Sixty-nine patients (58.5%) reported never having had a dilated fundus examination, whereas 31 (63%) of the 49 patients reporting a previous dilated examination were last examined more than 2 years before presentation. Timing of ophthalmic examination was classified as appropriate for 38 patients (32%), marginal for 20 patients (17%), and inappropriate for 60 patients (51%). CONCLUSION In the setting of an inner city county hospital eye clinic, where the patient population is predominately minority and of low socioeconomic status, ophthalmic surveillance of high-risk patients with diabetes is inadequate and advanced disease often is present at initial presentation. Strategies must be developed to increase the routine use of eye services within this population.

Corneoscleral laceration caused by air-bag trauma

PURPOSE To report a case of a corneoscleral laceration sustained as a direct result of inflation of a driver-side air bag. METHODS A patient who sustained a severe ocular injury in a low-speed motor vehicle accident underwent clinical and radiologic examination and subsequent treatment. RESULTS The left eye underwent primary repair of a complex corneoscleral laceration. Two weeks postoperatively, visual acuity in the left eye remained at bare hand motion. CONCLUSION Although air-bag-related eye trauma may be relatively infrequent, the severity of the injuries incurred warrant research efforts to explore new air-bag designs that minimize the risk of ocular injury.

Endophthalmitis and Orbital Cellulitis after Radial Keratotomy

PURPOSE To report the findings concerning three patients with endophthalmitis and one with panophthalmitis and orbital cellulitis radial keratotomy surgery. METHODS One man referred with panophthalmitis and orbital cellulitis and three women referred with endophthalmitis were treated. RESULTS After radial keratotomy surgery, during which no microperforation or macroperforation had been reported, a severe Pseudomonas panophthalmitis and orbital cellulitis developed in the man. All vision was lost in that eye. Staphylococcus epidermidis endophthalmitis developed in one woman, Streptococcus pneumoniae endophthalmitis in the second woman and Pseudomonas endophthalmitis in the third woman, after undergoing radial keratotomy procedures during which microperforations occurred. In the latter patient, bilateral simultaneous surgery was performed, but only one eye became infected. The latter two infections resulted in light perception and hand motion vision respectively. In three cases, an initial keratitis was located in the inferior cornea. CONCLUSIONS Severe bacterial endophthalmitis can occur after radial keratotomy surgery, even in the absence of microperforation during the procedure. Any evidence of postoperative keratitis must be regarded seriously and treated aggressively. Despite use of this approach, the effect on final visual acuity can be devastating.

Evaluation of intraocular lens power calculation formulas in the triple procedure

Purpose: To determine whether the choice of intraocular lens (IOL) power formula improves IOL power predictions and whether personalized constants within the IOL power formula are critical factors in improving refractive predictions after combined penetrating keratoplasty, cataract extraction, and IOL implantation. Methods: Records of 46 patients who had the triple procedure between January 1988 and December 1992 were evaluated using the SRK II, SRK/T, Holladay, and Hoffer Q formulas to predict the postoperative spherical equivalent refractions for implanted lens power. Calculations were carried out with and without the use of personalized constants. The predictive accuracy of each formula was assessed by comparing the actual postoperative spherical equivalent refractive error with that predicted by the formulas. The predictive error and the distribution of predictive errors were used to assess predictive accuracy. Results: There was no difference in the mean absolute predictive errors and the distribution of predictive errors for the four formulas evaluated (P < .05). The use of personalized formula constants significantly reduced the mean absolute predictive error for the SRK II, SRK/T, and Holladay formulas (P < .05) and approached significance for the Hoffer Q formula. Conclusion: The findings suggest that the choice of IOL power formula does not affect IOL power predictions in the corneal triple procedure; however, personalized constants within a formula appears to be a critical factor in improving postoperative refractive predictions.

Topographic detection of photorefractive keratectomy

PURPOSE This study aimed to evaluate the sensitivity and specificity of subjective review of corneal topography to detect patients who have undergone photorefractive keratectomy (PRK). METHODS Topographic maps from 3 different devices were obtained from 19 patients with postoperative PRK and 9 control subjects with emmetropia and 10 control subjects with myopia. Each image was printed in an absolute and relative scale (total of 228 maps) and graded for overall shape and pattern. Fifteen masked reviewers independently rated each map as either postoperative PRK or not. RESULTS The overall sensitivity (ability to detect PRK) and specificity rates (ability to exclude control subjects) by reviewers were 65% and 93%, respectively. Sensitivity was influenced independently by the scale (relative, 68%; absolute, 62%; P < 0.01), experience of reviewer (experienced, 77%; inexperienced, 53%; P < 0.001), and device (Alcon, 67 +/- 29.9; Eyesys, 75 +/- 29.4%; and Tomey, 54 +/- 31.7%; P < 0.001). Low levels of preoperative myopia were consistently more difficult to detect than higher levels (low myopia -1.50 to -2.99 diopters [D] sensitivity: 53 +/- 34.5%; medium level -3.00 to -4.49 D: 67 +/- 28.9%; and high level -4.50 to -6.00 D: 77 +/- 21.1%; P < 0.0001). Differences in specificity between experienced and inexperienced reviewers were obtained when maps had a homogeneous topographic pattern (97 +/- 5.6% and 85 +/- 13.7%, respectively; P < 0.05). Several control topography patterns (e.g., homogeneous, focal, and keyhole) were disproportionately more difficult to correctly identify on the Eyesys device. CONCLUSIONS Topographic experience is a significant factor influencing the correct identification of PRK. Techniques also can be used to enhance detection, such as the use of different devices and scales. However, if subjective review of topography is used as the only method of detection, many patients with PRK will not be identified properly. In addition, the most prevalent preoperative myopic category in the general population (myopia < -3.00 D) also is the most difficult to detect after treatment. This reduces the usefulness of topography as a screening tool. Other techniques are needed to improve the detection of patients with postoperative PRK.

Mechanical methods in refractive corneal surgery.

Over the past decade, keratorefractive surgery has moved into the mainstream of ophthalmology as improved instrumentation and newer techniques have evolved, these new aspects increase the safety and effectiveness of the various keratorefractive procedures. The introduction of new techniques and knife designs has led to improved results with radial keratotomy. The newly developed arcuate keratome purportedly offers the possibility of improving the predictability of arcuate keratotomy. Keratomileusis and epikeratoplasty have been successful for some difficult refractive states, such as aphakia and high myopia. Intracorneal lenses are showing promise in correcting high refractive errors and may offer an alternative to the more technically challenging lamellar procedures performed for correcting these conditions. Intrastromal ring implants are early in their clinical testing, but may provide an alternative to radial keratotomy for correcting myopia. The predictability, effectiveness, safety, and stability are far from perfect for current procedures, but recent results are encouraging.

Clusterin from human clinical tear samples: Positive correlation between tear concentration and Schirmer strip test results

PURPOSE To investigate the relationship between tear concentration of the homeostatic protein clusterin (CLU) and dry eye signs and symptoms, and to characterize tear CLU protein. METHODS Two independent studies were conducted, one in Tucson (44 subjects), the other in Los Angeles (52 subjects). A cohort study design was employed to enroll patients without regard to dry eye diagnosis. Dry eye signs and symptoms were assessed using clinical tests. Tear samples were collected by Schirmer strip, and also by micropipette at slit lamp when possible. CLU from both sample types was quantified by immunoassay. The relationship between CLU concentration and clinical test scores was determined by Pearsons correlation coefficient (for individual eyes) and multiple linear regression analysis (including both eyes). CLU was also evaluated biochemically by western blotting. RESULTS In the Tucson cohort, a positive correlation was observed between tear CLU concentration and results of the Schirmer strip test, a measure of tear flow (p = 0.021 includes both eyes). This result was corroborated in the Los Angeles cohort (p = 0.013). The mean tear CLU concentration was 31 ± 14 μg/mL (n = 18 subjects, 33 eyes; range = 7-48 μg/mL). CLU from clinical tear samples appeared biochemically similar to CLU from a non-clinical tear sample and from blood plasma. CONCLUSIONS Results support the hypothesis that an optimal concentration of tear CLU is important for ocular surface health, and that this drops below the effective threshold in dry eye. Tear CLU measurement might identify patients that could benefit from supplementation. Information about concentration will aid development of therapeutic dosage parameters.