The CLAO journal : official publication of the Contact Lens Association of Ophthalmologists, Inc最新文献

Purpose: To determine whether the widespread use of topical fluoroquinolones has changed the spectrum of ulcerative keratitis, and to determine how it has affected practice patterns in the treatment of corneal ulcers.

Methods: We retrospectively reviewed the charts of 48 consecutive patients with infectious corneal ulcers from 7/1/91 to 12/31/91 and 47 consecutive patients from 7/1/94 to 12/31/94. Patients were treated with intensive topical antibiotics (either standard fortified antibiotics or topical fluoroquinolones) at a frequency of at least every hour while awake. Some patients were admitted to the hospital, and some underwent scraping for smears and cultures.

Results: Ulcers which were seen in 1994 appear to have been more severe than those seen in 1991 as judged by the presence of more ulcers associated with hypopyons, (P< 0.05) but not with regard to the size of the infiltrate or epithelial defect. More ulcers in 1994 were treated on an outpatient basis (P< 0.02) and fewer ulcers were scraped and cultured than in 1991 (P< 0.001). Culture results from the 1991 and 1994 groups were similar. The most frequently isolated organisms were coagulase-negative Staphylococcus, Pseudomonas, Staphylococcus aureus, and Streptococcus spp.

Conclusion: The spectrum of ulcerative keratitis at a tertiary referral center may be showing a trend towards more severe ulcers, but the causative agents responsible for the infection are unchanged.

Purpose: To describe an unusual case of cicatrizing conjunctivitis.

Methods and results: A 59 year old male presented in July 1997 with a complaint of intermittent redness and discharge of the right eye. Medical history was significant for a buccal mucosal lesion biopsy taken two years earlier that revealed subepidermal fibrosis. Conjunctival biopsy, performed to rule out ocular cicatricial pemphigoid, yielded a diagnosis of linear IgA dermatosis, an unusual diagnosis not often considered by ophthalmologists.

Conclusions: The diagnosis of cicatrizing conjunctivitis is often overlooked. Its importance as it pertains to the life threatening disease of ocular cicatricial pemphigoid is clear.

Purpose: To determine if rigid gas permeable (RGP) or soft contact lenses can be successfully worn after photorefractive keratectomy (PRK) to correct residual refractive errors.

Methods: Patients with residual stable ametropia after PRK were fit with RGP or soft lenses. Manifest refraction, corneal topography, and keratometry were performed, and post-PRK corneal haze was graded during the study visits. Contact lens fit characteristics and comfort were assessed. Lens centration, visual quality, and ocular surface status were graded, and visual acuity with contact lenses was charted.

Results: Eighteen patients were recruited for RGP lens fitting. The mean refractive error post-PRK was +0.80 D +/- 2.03 (range: -3.50 to+3.00 D). The mean contact lens power was -3.90 D +/- 2.03 (range: 0 to -7.00 D), and the mean contact lens base curve was 7.88 mm +/-0.16. A significant positive tear film at the site of the central ablation was noted, contributing to excessive minus lens power in all cases. Despite mild to moderate lens instability and de-centration, 14 patients reported excellent visual quality with the lenses, and pre-PRK best-corrected acuity was achieved in all patients. Twenty-five percent (4 of 16) of the patients were able to wear the lenses all day. Eleven patients were recruited for soft contact lens fitting-five from the RGP trial. The mean refractive error post-PRK was -0.64 D +/- 2.01 (range: -3.50 to +1.75D). The mean contact lens power was -0.60 D +/- 2.07 (range: -3.75 to +2.5 D), and the mean contact lens base curve was 8.33 mm +/- 0.42. Eight patients were corrected with lenses to their pre-PRK best-corrected acuity, and nine patients reported excellent visual quality with the lenses. All the patients had excellent lens centration. Thirty-six percent (four of 11) of patients were wearing the lenses all day.

Conclusions: Fitting RGP lenses after PRK results in good visual acuity but may be associated with mild to moderate lens instability and decentration. Soft contact lens fitting also results in good visual acuity. Soft lenses were better tolerated by the subjects in our study because of improved lens centration and stability.

Purpose: The purpose of the study was to evaluate the on-eye dehydration over time, of molded omafilcon A lenses (Proclear Compatibles) compared to a range of frequent replacement lenses.

Methods: Ten subjects wore a Proclear Compatibles lens in one eye and a control lens in the other eye for 4-, 8- and 12-hours. The control lenses were Acuvue, Soflens 66 and Optima frequent replacement lenses. Each subject wore three different pairs of lenses for each time period in a masked, randomized fashion. A gravimetric technique was used to determine lens water content.

Results: The Proclear Compatibles lenses showed significantly less relative dehydration than the Acuvue and Soflens 66 lenses. The Acuvue and Soflens 66 lenses showed a significant increase in relative dehydration with increasing wearing time. Subjective comfort was graded higher with the Proclear Compatibles than with the Acuvue lenses. There was a significant negative correlation between Acuvue dehydration and subjective ratings of comfort.

Conclusions: The study showed that Proclear Compatibles lenses dehydrate significantly less than the other frequent replacement high-water content lenses. The Acuvue and Soflens 66 lenses showed increasing dehydration during the 4-12 hour wearing period.

Purpose: To evaluate the performance of silicone elastomer lenses in pediatric eyes with aphakia.

Methods: We retrospectively studied pediatric aphakic eyes fit with Silsoft lenses (elastofilcon A, Bausch & Lomb) at the L.V. Prasad Eye Institute, India.

Results: Seventy-four children (106 eyes) with a median age of 9.0 months (range: 1 month to 12 years) were included in the study. Congenital cataract was the pre-existing pathology in 84 eyes. Lenses were fit between 1 week and 5 years following surgical intervention (median: 25 days). The most frequently used base curves were 7.5 mm (n=46 eyes) and 7.7 mm (n=39 eyes); lens diameter was 11.3 mm (n=103 eyes). Satisfactory fit was achieved in 86 eyes (81.1%). One-week extended wear was the most commonly recommended mode of wear (n=95 eyes). Lenses (n=118) were replaced for change of power, lens loss, and deposits or damage. Lenses were worn for > or =6 months in 68 eyes (64.2%). Twenty-three contact lens related adverse events occurred, all of which resolved uneventfully. On survival analysis, the probability of not having a lens related complication was 75.5% (95% CI; 61.5-89.5) at 24 months.

Conclusions: In the management of pediatric aphakia, Silsoft lenses are safe, provide satisfactory optical correction, and are easy to handle. Limited availability and the financial costs associated with frequent lens replacement are limitations in our socioeconomic circumstances.

Purpose: To ascertain the incidence of microbial contamination of preserved contact lens saline solutions with normal patient use.

Methods: Eight different brands of preserved saline were dispensed to 40 patients attending optometric practices in the Sydney area. After specific periods of time (7 to 28 days), the samples were collected and the solution bottle nozzles and contents underwent microbial analysis.

Results: The overall contamination rate was approximately 26% for contents only and 55% for nozzles of preserved saline solutions. This rate remained constant for all periods of use. Coagulase-negative Staphylococci were most frequently isolated. No Acanthamoebae were isolated. Saline preserved with ethylene-diamine-tetraacetic acid (EDTA) in conjunction with sorbic acid showed the highest percentage of sterility.

Conclusions: The results of this study show that preserved saline became contaminated with gram-positive bacteria. This is in contrast to our previously published paper using unpreserved saline, where contamination was predominantly with gram-negative bacteria. The overall contamination rates with preserved saline were lower than for unpreserved saline.

Purpose: Oxygen transmissibility is a key determinant of the physiological response of the cornea to contact lens wear. Because transmissibility is related to hydrogel water content, we conducted a study to determine the change in water content during lens wear and to quantify the impact any such change would have on transmissibility.

Methods: In a double masked clinical investigation, two subjects each wore 17 different pairs of contact lenses. Water content was measured before lens wear at 35 degrees C and immediately after 4 hours of contact lens wear. Contact lens oxygen transmissibilities were calculated on each occasion.

Results: The absolute changes in water content for the 17 lenses varied from +0.5% to -5.3%. For some lenses, this change in water content altered the lens oxygen transmissibilities to a clinically significant degree. The changes in water content and oxygen transmissibilities were greatest with FDA Group IV lenses.

Conclusions: Dehydration during contact lens wear can alter the oxygen transmissibility of hydrogel lenses, and in some situations, this factor may be clinically significant.

Purpose: Contact lens wear has the potential to cause an acquired non-senile blepharoptosis. Ptosis can result from rigid gas permeable (RGP) contact lens wear due to contact lens migration, inflammation, and undetermined causes. The purpose of this article was to investigate the occurrence of ptosis without obvious cause in a young and middle aged RGP contact lens wearing population.

Methods: We fit sixty-four patients (128 eyes) with RGP contact lenses over a fifteen month period (7/1/96 to 9/10/97) and present a series of case reports of five young and middle aged RGP contact lens wearers who developed ptosis without obvious cause during the study period.

Results: Five patients (6 eyes [4.7%]) in our study developed non-senile acquired ptosis. Four patients had a unilateral ptosis, and one patient had a bilateral ptosis.

Conclusions: As in other other studies, we found that a significant percentage of RGP contact lens wearers developed ptosis, which is suspected to be related to RGP contact lens wear. One possible explanation is the lens removal procedure of pulling laterally on the eyelids followed by a harsh blink. However, other causes may exist such as the constant rubbing of the lens edge against the palpebral conjunctiva.

Purpose: This prospective study was designed to subjectively and objectively evaluate the performance of an aspheric multifocal back surface rigid gas permeable (RGP) contact lens. The multifocal element of this lens design consisted of an aspheric optical zone that varied according to the patient's ametropia, corneal topography, and required reading addition.

Methods: We fit 28 presbyopic subjects with an aspheric multifocal back surface RGP contact lens (age range: 45 to 68 years). Reading additions ranged from +0.75 D to +2.50 D. Subjects were assessed initially and at 2, 6, and 12 weeks for ocular changes, visual performance, and subjective responses.

Results: We required 116 RGP lenses to achieve an acceptable fit and visual acuity in 28 subjects (55 eyes). At the final visit, the distance logMAR acuity with the multifocal contact lens (+0.12 +/- 0.10) was not statistically different (t = -0.623, P = -0.5388) from spectacle acuity at the initial visit (+0.10 +/- 0.12). The near logMAR acuity with the multifocal contact lens at the final visit (0.36 +/- 0.12) was not statistically different from that for near acuity with spectacles at the initial visit (0.33 +/- 0.13). No slit lamp signs worsened during the study. A reduction in myopia of 0.67 D was noted by the final visit. Spectacle blur was noted if the acuity at the initial refraction was compared to the acuity with the same refraction at the final visit (t = -3.287, P = 0.0028) but not when the refractive changes were incorporated (t = 1.058, P = 0.3127). All subjects rated the performance of the lenses very highly: comfort, 86%; distance acuity, 83%; near acuity, 73%; and stability of vision, 74%. Twenty-four subjects (86%) chose the multifocal contact lens as their preference.

Conclusion: We demonstrated that a multifocal design is able to provide acceptable distance and near correction for presbyopic patients. The aspheric geometry required can be optimized for a given patient by considering his/her degree of ametropia, as well as the corneal topography.