Does identification of the causal organism of corneal ulcers influence the outcome?

PURPOSE: To investigate whether identification of the causal organism in corneal ulcers influences their outcome. METHODS: We retrospectively studied 114 patients, 72 males and 42 females aged 6-89 years, admitted to this eye clinic during the years 1994-2000 on account of an infectious corneal ulcer. Their examination included a detailed history, visual acuity measurement, and biomicroscopy in everyday follow-up. The ulcers were classified according to their severity and outcome. We assessed the cases where cultures had been done, reviewed the results, and searched for a possible correlation between the outcome and the fact of culturing the ulcer and identifying the causal organism. RESULTS: Of the 114 corneal ulcers studied, 23 were mild, 49 moderate, and 42 severe. Fifty (44%) had not been cultured, but 64 ulcers (56%) had been cultured, with a positive result in 37 cases (58%), Staphylococcus and Pseudomonas species being the most common organisms found. In moderate and severe ulcers, there was a tendency to a higher proportion of successful outcome for cultured ulcers, but with no significant correlation. CONCLUSIONS: Despite a tendency towards favorable results in culture-positive corneal ulcers, the influence of the detection of the organism on their outcome has not been proved. The role of the initial broad-spectrum antibiotic therapy remains important.

Corneal complications following abuse of topical anesthetics.

PURPOSE: To describe corneal complications in three patients following abuse of topical anesthetics. MATERIALS AND METHODS: We describe one case with bilateral corneal perforation, another with unilateral corneal perforation and a third case of chronic keratitis following excessive use of topical anesthetics. RESULTS: Two patients continued to instill topical anesthetic drops despite all recommendations to stop. The result was a bilateral corneal perforation in the first case and a large unilateral descemetocele in the second. The third patient who had chronic toxic keratitis discontinued the anesthetic drops and after the appropriate treatment the cornea returned to normal. Corneal grafting and conjunctival flaps were used to seal the corneal perforation but the long-term anatomical and functional results were very poor. CONCLUSIONS: The initial presentation of this rare clinical entity creates difficulties in reaching a correct diagnosis. A presumed acanthamoeba keratitis is the first choice among many similar conditions. Thus abuse of topical ocular anesthetic drops should be included in the differential diagnosis of cases of chronic keratitis as it may masquerade as acanthamoeba keratitis. A current or past history of psychiatric and mental disorders or psychoactive substance abuse is important in the diagnosis. Functional and anatomical results after appropriate treatment are usually poor. Psychiatric counselling is extremely helpful and is in fact mandatory in the management of these patients.

Levels of specific antibodies towards the major antigenic determinant of slime-producing Staphylococcus epidermidis determined by an enzyme immunoassay and their protective effect in experimental keratitis.

Staphylococcus epidermidis is an important cause of bacterial keratitis. Certain S. epidermidis strains produce an extracellular slime layer rich in an acidic polysaccharide with a molecular size of 20 kDa (20-kDa PS). We have demonstrated that the level of 20-kDa PS-specific antibodies significantly rises after establishment of slime-producing S. epidermidis bacteraemia and, furthermore, that rabbit polyclonal antibodies to 20-kDa PS opsonize cells of slime-producing S. epidermidis to a great degree and promote their clearance by polymorphonuclear cells (Arch. Biochem. Biophys. 342 (1997) 389; J. Pharm. Biomed. Anal. 22 (2000) 1029). The purpose of this study was to examine the protective and therapeutic effects both of active immunization, using 20-kDa PS as antigen, and of passive administration of specific antibodies towards the 20-kDa PS in a rabbit keratitis model. For active immunization, 20 rabbits were subcutaneously immunized with 20-kDa PS, whereas for passive immunization specific polyclonal IgG antibodies against 20-kDa PS were administered to 20 rabbits 1 day before induction of infection. Clinical observations were made weekly for 1 month and levels of 20-kDa PS antibodies in serum and aqueous humor in both immunization groups were determined by an enzyme immunoassay. The levels of specific anti-20-kDa PS IgG in serum and aqueous humor following either active or passive immunization were significantly higher as compared with control groups (P<0.001). Although, actively immunized rabbits showed significantly less corneal damage than control animals, passively immunized ones were significantly better protected as compared with both control and those actively immunized. Obtained results suggest that 20-kDa PS plays crucial role in the pathogenesis of S. epidermidis keratitis and that both types of immunization significantly protect against corneal S. epidermidis pathology and damage.

Evaluating the management of diabetic retinopathy in a teaching center.

PURPOSE: To evaluate the efficacy of the management of diabetic retinopathy (DR) in the teaching center of the University Eye Clinic of Patras in Greece. METHODS: From 1989 to 1999, 302 patients with type I (5.3%) and type II (94.7%) diabetes mellitus (DM) were examined. Standard examination and treatment protocols were employed. Examinations and laser treatment were done by trainee specialists, under the supervision of the head physician (N.Ph), during their rotation in the retina and vitreous disorders outpatient department. RESULTS: At baseline examination, 17.9% of the eyes had no DR, 71.7% had nonproliferative DR, and 10.4% had proliferative DR. In 34.4%, no laser treatment followed. The other 65.6% underwent focal and/or grid laser and/or panretinal photocoagulation and/or vitrectomy. At the final examination, DR was still the same in 63.1% of the eyes, progression had occurred in 34.1%, and regression in 2.8%. Type I DM patients' eyes had a higher prevalence of proliferative DR at the final examination than type II DM eyes. There was also a significant correlation between progression of DR and duration of DM, insulin treatment for DM, and elevated glycosylated hemoglobin (HbA1c). CONCLUSIONS: Having applied standard examination and treatment protocols, the efficacy of the management of our diabetic patients was consistent with international standards, even though patients were treated mostly by doctors in training.

Bilateral panophthalmitis as the initial presentation of meningococcal meningitis in an infant.

Endophthalmitis is a well-recognized, frequently devastating ophthalmic disease. The colonization of the eye and the subsequent development of endophthalmitis may be exogenous (including postsurgical and post-traumatic infections) or it may be of endogenous origin, representing a metastasis from a focus of infection elsewhere in the body associated with bacteremia (such as meningitis or cellulitis).

Comparison of lodoxamide 0.1% ophthalmic solution and levocabastine 0.05% ophthalmic suspension in vernal keratoconjunctivitis.

PURPOSE: To compare the clinical efficacy and safety of lodoxamide 0.1% ophthalmic solution with levocabastine 0.05% ophthalmic suspension, each given four times daily (QID) for three months to patients with vernal keratoconjunctivitis (VKC). METHODS: The study was conducted multinationally according to a triple-masked parallel design in 95 VKC patients, with assessments at baseline then monthly during the three months of treatment. The primary efficacy variables were a Physician's Clinical Judgement Scale and a Patient's Overall Judgement Scale of improvements from baseline. Signs and symptoms of VKC were also assessed. RESULTS: Both primary efficacy variables showed significantly greater overall improvement of VKC from baseline with lodoxamide than levocabastine. The superiority of lodoxamide was demonstrated by the Physician's Clinical Judgement Scale at months 2 and 3, with a trend, at month 1, and by the Patient's Overall Judgement Scale at months 1, 2 and 3. All signs and symptoms of VKC improved significantly from baseline at all time points, regardless of treatment (p<0.001). However, relative to levocabastine, conjunctival discharge, photophobia and lacrimation were significantly reduced by lodoxamide at months 1, 2 and 3, itching at months 2 and 3, and bulbar conjunctiva at month 3. The temporal improvement of superior tarsal papillae did not differ significantly between treatments. Both were well tolerated. CONCLUSIONS: Lodoxamide 0.1% and levocabastine 0.05% eye drops, instilled four times daily for three months, were effective, safe and well tolerated by patients with VKC, but lodoxamide was significantly superior to levocabastine.

Contrast sensitivity function in patients with impaired oral glucose tolerance.

PURPOSE: To evaluate contrast sensitivity function in patients with impaired oral glucose tolerance test (OGTT) compared with normal subjects. METHODS: Sixteen patients with impaired OGTT and 11 normal control subjects were tested for contrast sensitivity function at four spatial frequencies. Glucose intolerance was established by the 1985 World Health Organization criteria. RESULTS: The two groups were similar in terms of age, visual acuity, refractive correction, and lens opacities. A statistically significant loss of contrast sensitivity was associated with impaired OGTT (p < 0.001) in every spatial frequency tested. CONCLUSIONS: Functional visual loss in patients with impaired glucose tolerance using the 1985 World Health Organization criteria indicates that at least part of those patients should be classified as diabetic according to the 1997 American Diabetic Association criteria. It seems that the 1997 American Diabetic Association criteria are more efficient at detecting patients with abnormal visual function.

Contrast sensitivity function in patients with beta-thalassemia major.

PURPOSE: To investigate contrast sensitivity function in patients with beta-thalassemia major, after regular transfusion and chelation therapy. METHODS: We measured contrast sensitivity at four spatial frequencies in 30 patients with beta-thalassemia major and in 30 matched normal control subjects. All subjects underwent an ophthalmic examination that included fluorescein angiography. The contrast sensitivity results from the two groups were compared between them. Patients' contrast sensitivity values were correlated to the variables age, duration of transfusion, duration of chelation therapy and serum ferritin levels, to select the important predictors. RESULTS: Contrast sensitivity function in all beta-thalassemic patients was significantly lower (p<0.0001) compared to the normal control subjects, for all spatial frequencies tested. The most important predictor of contrast sensitivity loss was patients' age. CONCLUSION: Contrast sensitivity testing can detect early changes in the visual function of beta-thalassemic patients and should be considered as a monitor for patients under chronic transfusion-chelation therapy.

Use of topical brimonidine to prevent intraocular pressure elevations following Nd:YAG-laser posterior capsulotomy.

BACKGROUND AND OBJECTIVE: To evaluate the efficacy of topical brimonidine tartrate 0.2% (Allergan, Irvine, CA) in the prophylactic treatment of acute intraocular pressure (IOP) rises following Nd:YAG laser posterior capsulotomy. PATIENTS AND METHODS: This was a double-masked, randomized, placebo-controlled clinical study in 60 patients who underwent Nd:YAG laser posterior capsulotomy after extracapsular cataract extraction. Two doses of brimonidine or vehicle were administered before and after capsulotomy. Intraocular pressure was measured prior to commencing instillation and for 48 hours postoperatively. RESULTS: Following posterior capsulotomy, the brimonidine group showed a significant mean percent reduction in IOP, while the vehicle group showed a significant mean percent increase in IOP. At 48 hours, mean IOP of both groups had returned to pre-laser level. There were no differences between the 2 groups in the incidence of clinical adverse experiences. CONCLUSION: Two-dose brimonidine tartrate 0.2% effectively prevents acute IOP rises after Nd:YAG laser posterior capsulotomy.

Contrast sensitivity after extracapsular and intracapsular cataract extraction.

Contrast sensitivity function after cataract extraction and intraocular lens implantation has been mainly correlated to the type or the material of the intraocular lens. Our purpose was to identify other possible factors, like posterior capsule, to contrast sensitivity alterations after cataract surgery, comparing patients operated for cataract by techniques that mainly differed on the posterior capsule's integrity. The intraocular lens implanted was either a posterior or an anterior chamber one, always monofocal and made of PMMA. We measured contrast sensitivity function at four spatial frequencies in two groups of operated individuals (group A and B) and in one group of healthy control individuals. Each group consisted of 42 eyes. Group A comprised eyes with intact, clear posterior capsule and posterior chamber monofocal intraocular lens. Group B comprised eyes with ruptured or removed posterior capsule and anterior chamber monofocal intraocular lens. Control group comprised healthy control eyes. A pair matched design was used to compare contrast sensitivity values among the individuals of the three groups. No statistically significant differences in contrast sensitivity values were found when group B patients were compared to healthy controls (p >0.05). Patients of group A exhibited contrast sensitivity function impairment at intermediate and high spatial frequencies when compared to patients of group B (p <0.05) and to controls (p <0.01). It seems that intact posterior capsule provides inferior visual function, in spite of relatively good visual acuity and apparently satisfactory results.

Contrast sensitivity function after cataract extraction and intraocular lens implantation.

Divergent contrast sensitivity findings have been reported in patients with intraocular lens implants. The purpose of this study was to determine contrast thresholds of patients with good visual acuity after uncomplicated cataract extraction and posterior chamber conventional IOL implantation. Fifty-two eyes of fifty two patients, who had undergone uncomplicated extracapsular cataract extraction and posterior chamber intraocular lens implantation together with 48 eyes of 48 control subjects were tested for contrast sensitivity function. All of the patients had best corrected visual acuity 0.8 (20/25) or better, on the Snellen scale. Patients with concomitant eye disease were excluded. Contrast sensitivity was measured using stationary sine-wave gratings of four spatial frequencies (3.0 to 18.0 cycles/degree), at the testing distance of 8 feet. A loss of contrast sensitivity was found in patients with intraocular lens implants, compared with control subjects of similar age, sex and visual acuity. The loss was statistically significant at intermediate (6 cyc/deg) and high spatial frequencies (12.0 and 18.0 cycles/degree), while it was not statistically significant at low spatial frequencies (3 cyc/deg). This may be the reason of nonspecific visual complaints ('washed-out images'), despite normal Snellen acuity, after cataract surgery and monofocal IOL implantation.

Clinical trial with diffractive multifocal intraocular lens implantation.

This study presents results obtained after implantation of 25 diffractive multifocal intraocular lenses. The follow-up ranged from six to 12 months. Visual acuity for distance without correction was 0.5 or better in 72% of cases; for near, it was J1 to J3 in 84% of cases. Slight decentration of the lens and pupil size did not affect visual acuity.

The corneal epithelium basement membrane complexes after alkali burn: an ultrastructural study.

Chemical burns were produced using a 4 N NaOH solution in 21 rabbit corneas. The ultrastructural findings were examined under an electron microscope five minutes and 1, 2, 4, 8, 15, and 30 days after the burn. A morphologic disturbance of the basement membrane and its complexes was detected from the first day of the experiment. These findings suggest that the basement membrane plays an important role in the pathogenesis of corneal recurrent erosions and ulcer formation after chemical burns.

Acyclovir--a promising antiviral agent: a review of the preclinical and clinical data in ocular herpes simplex management.

Acyclovir (Aciclovir), previously known as acycloguanosine, has been found to be a potent and selective inhibitor of viruses of the herpes group. A clear therapeutic effect has been demonstrated in animals and in clinical studies, especially for herpes simplex virus (HSV) infection of the eye. Various reports indicate that acyclovir is as effective as or superior to other available antiviral agents with low host toxicity and mild side effects. The possibility of systemic use of this drug and the effect on HSV latency are encouraging, although more evaluation is needed. Acyclovir is a promising new antiviral agent for the topical treatment of HSV ocular infection.

Epidemiologic research on the role of studying and urban environment in the development of myopia during school-age years.

Four hundred seventy-four Greek male subjects received an ophthalmologic examination and completed a questionnaire. The following were found: (1) the years of studying and urban residence are factors that strongly influence the prevalence of myopia; discriminant factor analysis classified correctly 81% of the subjects into the myopic or the nonmyopic group; (2) the incidence of myopia is significantly higher in the studying v the nonstudying groups; (3) the prevalence of myopia is higher in the more educated group; (4) there is no statistical difference between the orientation of myopes and nonmyopes toward studies or other occupations; (5) although the presence of myopia is determined by the years of studying and urban residence, the degree of myopia is not influenced to a statistically significant level by these factors; and (6) the results indicate that the interaction of these two variables is more significant in their contribution to the onset of myopia than the sum of each variable alone.

Visual correction of keratoconus with soft contact lenses.

Soft contact lenses were fitted on 96 eyes of 52 patients suffering from keratoconus. The visual acuity of 66 eyes was 4/10 or better with soft contact lenses alone. The amount of astigmatism corrected with soft contact lenses varied between 1.50 and 8.00 D, with an average of 2.80 D. Sixteen eyes had a residual astigmatism. Correcting this astigmatism with spectacles resulted in improved visual acuity, and finally, 71 eyes, or 74%, had a visual acuity 4/10 or better. Soft contact lenses of three manufacturers, Bausch & Lomb (the C series), Nusyte, and Bioflex, were used. Thicker lenses corrected more astigmatism and provided an improved visual acuity, especially the C series lenses of Bausch & Lomb, which presented certain advantages in visual correction of keratoconus patients.

Response of the cornea to far ultraviolet light: an ultrastructural study.

Quantitative changes were measured and ultrastructural alterations were detected in rabbit corneas after exposure to a far ultraviolet irradiation (UV). Low dose exposure (105 - 8 x 105 erg/cm2) resulted one day later in a thicker epithelium and loss of the intercellular permeability barrier. In corneas exposed to higher doses (5 x 106 erg/cm2), the epithelium was considerably thinner one day later, whereas 4 days later it was of normal thickness and the endothelial cells became degenerated. The highest UV dose exposure used (a total of 20 x 106 erg/cm2 given in 4 equal daily doses) resulted in (1) swelling of the stroma and disorganization of the collagen fibers; (2) disappearance of the basement membrane; (3) degeneration of the endothelial cells; and (4) considerable reduction of epithelium thickness.

Excretion of vanilmandelic acid in the urine of retinoblastoma patients.

The idea of determining the urinary excretion of vanilmandelic acid (VMA) in children with retinoblastoma derives from the fact that elevated amounts of VMA were found in children with neurogenic tumours and especially neuroblastoma. The method of VMA analysis and the results are discussed. In view of the fact that in only 5 out of our 12 patients an elevated urinary VMA excretion was found, we cannot recommend this determination as a routine diagnostic procedure. However, further research in this direction is necessary.