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

Purpose: A randomized crossover comparison of Transitions Gray variable tint optics (VTO) vs clear and fixed-tint lenses was undertaken to evaluate the impact of VTO on vision-related quality of life (VRQOL) in a warm climate.

Methods: Fifty-nine patients were randomized to one of four lens crossover groups: Transitions-->clear; clear-->Transitions; Transitions-->fixed-tint; fixed-tint-->Transitions. Each lens was worn for 30 days. VRQOL was measured using a newly developed and validated questionnaire instrument-the Transitions VRQOL. Changes in visual acuity were assessed by functional exam.

Results: Overall, Transitions was associated with the greatest improvement in VRQOL relative to clear and fixed-tint lenses without compromise in acuity. Transitions proved statistically superior to clear lenses, most notably in vision comfort both indoors and outdoors. Seventy percent of all patients selected Transitions as their primary lens at the end of the study.

Conclusions: Transitions brand VTO offer patients significant and clinically meaningful improvements in VRQOL superior to clear lenses. VRQOL assessments provide clinicians with valuable information above and beyond visual acuity to help optimize lens product selection and enhance patient satisfaction.

Purpose: We investigated the value of newly developed systems for parameter selection on the performance of high Dk rigid gas permeable (RGP) contact lenses with a spheric-aspheric design made of Boston Equa material in normal daily wear conditions. A comparison was also made between the safety and efficacy of a traditional care system vs a one-step chemical care system during the follow-up period of 1 year.

Methods: A total of 66 patients were randomly assigned to traditional and newly developed systems for computing the back optical zone radius (BOZR) and the total diameter (TD) of the lenses. Evaluation parameters incorporated assessment of fit, visual acuity, wearing time, comfort, and lens condition.

Results: The traditional method of computing the BOZR, using a method based on flat-K, predicted the BOZR successfully in 83% of the cases. Corneal topometry reached a lower, but not significantly different (P > 0.01) value of 75% correct prediction of BOZR. Analysis of the differences in eccentricity (E) values between quadrants per eye was a significant (P < 0.001) factor in fault predictions in the topometric system. A newly developed guide forTD selection performed, with 90% correct predictions, significantly (P < 0.01) better than a traditional method (72%) based on corneal diameter on supraversion. No significant differences (P > 0.05) were found in the capabilities of care systems (a traditional care system using a surfactant cleaner vs a one-step solution) to keep the lenses in proper condition and without deformation, over the 1 year follow-up period. The final success rate was 85%.

Conclusions: Although high Dk RGP contact lenses can be fit and used with a 85% success rate using advanced systems for determining the BOZR and TD, it remains necessary to evaluate the fit before dispensing high Dk RGP lenses in 15% of the cases. The one-step solution used in this study was a good starting point for lens care. If needed, surfactant cleaning in the traditional care system can be done without the risk of lens deformation.

Purpose: Experience with high Dk silicone hydrogel lenses has revealed post-lens debris, which is characterized by the appearance of spherical, translucent particles referred to as "mucin balls." The objectives of this analysis were to characterize the presence of mucin balls, determine whether any ocular characteristic predicts the development of mucin ball debris, and determine whether there is any association between mucin balls and the ocular response to contact lens wear.

Methods: Ninety-two subjects wore lotrafilcon A lenses on an extended wear basis for up to 30 nights and were followed for 6 months. Mucin balls were graded on a 0 to 4 scale at three visits. Subjective ratings and biomicroscopic appearance were recorded at all visits.

Results: Mucin balls were observed in 70% of subjects at one or more visits, and 29% of subjects at all three visits. There was no change in the mean grade of mucin balls over time. Mucin balls were graded > 1 in 20% of eyes, > 2 in 6% of eyes, and > 3 in 2% of eyes. Subjects who exhibited mucin balls at each clinical visit had significantly steeper keratometry readings along the flatter meridian (44.3 D) than those who never exhibited mucin balls (42.9 D, P < 0.0001). The percentage of subjects who "never" use lubricating drops was higher in the subjects with mucin balls (P = 0.0014). No association was found between mucin ball observation and biomicroscopic appearance, inflammatory responses, or subjective responses.

Conclusions: The presence of mucin balls does not appear to be detrimental to contact lens wear. Eyes with steeper corneal curvature were significantly more likely to present with mucin ball debris, indicating they may be a function of lens fit. Clinical factors that may be modified in order to manage the more severe presentation of mucin balls are the use of lubricating drops and the number of nights extended wear schedule.

Purpose: To determine the incidence of contact lens-related complications in various daily wear contact lens modalities.

Methods: The charts of 138 daily wear contact lens patients (35 daily disposable, 34 two week replacement, 34 frequent replacement, and 35 conventional daily wear lens users) were reviewed for subjective and objective contact lens problems. We also looked at two subgroups: first time lens wearers and patients with previous lens-related problems. The rate of lens related complications were calculated as events per person per year (E/P/Y) of lens wear for each year and for the total 3-year study. The percentage of patients in each group who experienced any complication was calculated. We also compared the complication rate for the groups in our current study to the rates calculated for disposable extended wear and conventional extended wear patients from our previous study.

Results: We found that the E/P/Y were significantly lower for daily disposable lens wearers, but no significant differences were noted for all other lens wear modalities. There was a trend in most groups toward decreased numbers of complications in the second and third years of lens wear. Of the 23 individual signs and symptoms that were analyzed, three occurred most frequently among daily disposable lens wearers, two were most common in the 2-week replacement group, four occurred most often in frequent replacement patients, and eight were most frequent in conventional daily lens wearers. (In three categories, there were two groups with ties for the highest rate of occurrence, and two categories with zero rates for all groups.) Most of the observed differences in complication rates for individual signs and symptoms did not reach the level of statistical significance.

Conclusions: Daily disposable lens wearers had the lowest overall complication rate.

Purpose: Two types of daily disposable soft contact lenses, 1-Day Acuvue (Johnson & Johnson K.K., Japan) and Focus Dailies (CIBA Vision Corp.), were compared for comfort, user preference, and any associated incidence of corneal complications.

Methods: 1-Day Acuvue and Focus Dailies were randomly prescribed for one eye each of 127 contact lens wearers. After 1 week of lens wear, user preference, anterior segment health, and tear film stability on the contact lenses were evaluated.

Results: Group A consisted of 45 subjects who had been wearing 1-Day Acuvue prior to the study and group B consisted of 82 subjects who had been wearing other types of soft contact lenses prior to the study. A statistically significant number of subjects in both group A and group B preferred 1-Day Acuvue. In group A there were significantly fewer corneal complications in the eyes with 1-Day Acuvue than in the eyes with Dailies. However, there was no difference in the incidence of corneal complications in group B.

Conclusions: If Dailies are prescribed for current 1-Day Acuvue wearers, extra care may be required. 1-Day Acuvue lenses could be prescribed successfully for those who previously wore soft contact lenses other than 1-Day Acuvue.

Purpose: To describe a case of fungal keratitis in a soft contact lens wearer.

Methods and results: A 57 year old female, compliant, frequent replacement soft contact lens wearer, with a possible prior history of herpes simplex keratitis, presented with pain and injection of her left eye of four weeks duration. Gram stain of a corneal ulcer of the left eye revealed fungal organisms and cultures grew Fusarium solani. The infiltrate responded to topical and systemic antifungal agents, but a corneal perforation developed which required a therapeutic penetrating keratoplasty.

Conclusions: Fungal infections are a cause of corneal ulcers in contact lens wearers. Despite the use of topical and systemic antifungal agents, fungal ulcers frequently require surgical intervention.

Purpose: To compare the keratometric readings obtained from Intraoperative PAR Corneal Topography System (IOPAR) to those produced by manual keratometer (Mnl-Km), autokeratometer (Auto-Km), EyeSys CAS (EyeSys Corneal Analysis System) and slit lamp PAR CTS in healthy eyes.

Methods: All instruments were calibrated prior to use and only data from the best image obtained was used for statistical analysis. Simulated keratometry readings obtained from the central 3-mm zone of the corneas by IOPAR, including flat (K1) and steep (K2) keratometry readings, average keratometric power (AK), astigmatism (As) (difference between steep and flat keratometry readings) and the axis of the steep meridian (Ax) were compared to those from four other units. The latter units were also compared among themselves. Statistical analysis was done for right and left eyes separately. For each variable, average differences between the measurements taken from pairs of instruments were estimated, with corresponding 95% confidence intervals. The degree of agreement between pairs of instruments on individual measurements was additionally assessed, via the use of "Bland-Altman"-type plots, and estimates of the proportion of cases achieving satisfactory agreement. Additionally, for every variable, the average of the measurements taken from the different instruments were compared.

Results: Forty-five (22 right and 23 left) normal corneas of 26 volunteers were examined. On the average, IOPAR tended to measure K1 higher than slit lamp PAR CTS system. Because K2 measurements taken by the IOPAR were higher than that of all other instruments, the As measurements, on the average, were also higher than that of others, with the exception of the PAR CTS. For the same reasons, the IOPAR produced average AK readings that were higher than those taken by EyeSys CAS and PAR CTS. When the individual measurements taken by the IOPAR were compared with each of the other units, according to the arbitrary designation of satisfactory agreement within +/-0.5 D (for K1, K2, AK, and As) and +/-20 degrees (for Ax), for almost all parameters, proportion of differences that were within the agreement range varied from 0.33 to 0.82, with wide confidence intervals (confidence interval lower limits ranging from 0.20 to 0.61 and upper limits ranging from 0.62 to 0.94).

Conclusions: IOPAR is a clinically useful topographic system, producing qualitative and quantitative data in the operating environment that, in normal corneas, on the average, matches those produced by the other units in the clinic. When individually analyzed, its keratometric measurements may show greater variations with respect to other units. Further studies with multiple examiners, in corneas with high or irregular astigmatism are required to establish its reproducibility and efficacy.

Purpose: Many explanations have been offered for why a large segment of the population develops dry eye. The purpose of this paper is to describe a new unifying theory of dry eye that incorporates all of these causes.

Methods: Data from the Department of Ophthalmology, University of Iowa Hospitals and Clinics was analyzed from 520 patients with dry eye, blepharitis and other conditions to assess the relationship between dry eye and blepharitis. This data was reviewed in terms of the relationship between dry eye, menopause, and aging. Also examined in detail were many of the proposed causes for dry eye in the literature.

Results: A close relationship between corneal damage and lacrimal gland function is hypothesized. Not only does decreased lacrimal gland output damage the ocular surface, but also damage to the corneal surface creates a negative feedback loop and damage to the lacrimal gland. There are probably several mechanisms by which this feedback occurs. One mechanism results from interruption or damage to the sensory corneal nerves. Damage to the nerves within the lacrimal gland may be another mechanism. Alteration of growth factor levels in the lacrimal gland, which occurs following corneal damage, represents another possible mechanism. Contact lenses and corneal refractive surgery are additional elements that may create negative feedback to the lacrimal gland.

Conclusion: The ocular surface and the lacrimal gland functions as a tightly integrated unit. Dry eye conditions damage the ocular surface and this in turn leads to further damage to the lacrimal gland.