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The medical use of contact lenses is a solution for many complex ocular conditions, including high refractive error, irregular astigmatism, primary and secondary corneal ectasia, disfiguring disease, and ocular surface disease. The development of highly oxygen permeable soft and rigid materials has extended the suitability of contact lenses for such applications. There is consistent evidence that bandage soft contact lenses, particularly silicone hydrogel lenses, improve epithelial healing and reduce pain in persistent epithelial defects, after trauma or surgery, and in corneal dystrophies. Drug delivery applications of contact lens hold promise for improving topical therapy. Modern scleral lens practice has achieved great success for both visual rehabilitation and therapeutic applications, including those requiring retention of a tear reservoir or protection from an adverse environment. This report offers a practical and relevant summary of the current evidence for the medical use of contact lenses for all eye care professionals including optometrists, ophthalmologists, opticians, and orthoptists. Topics covered include indications for use in both acute and chronic conditions, lens selection, patient selection, wear and care regimens, and recommended aftercare schedules. Prevention, presentation, and management of complications of medical use are reviewed. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of toric and soft spherical contact lenses on the visual performance and wavefront aberrations in cases of low astigmatism. Material and Method: Twenty-four eyes of 14 contact lens users with cylindirical refractive error of -1.25 diopters or less were included in this prospective study. The subjects wore spherical (lotrafilcon B) and toric (galyfilcon A) lenses for eight hours with a one-week interval. The best-corrected visual acuity and contrast sensitivity were measured before and after 8 hours of contact lens wear. Corneal topography and wavefront analysis were also performed. Zernike coefficients were used to calculate the aberrations at a 6-mm pupil diameter. Total and higher-order root mean square (RMS) values as well as spherical and coma aberrations were measured. Result: The mean spherical refractive error of the cases was -2.52±1.25 (range: from -0.50 to -6.0) D. The mean best- corrected visual acuity was significantly higher with both types of contact lenses than with glasses (p=0.017), however, no statistical difference was observed between the two types of contact lenses (p=0.470). The mean high-frequency contrast sensitivity value was lower with toric lenses (p=0.038). The mean higher-order RMS value was higher with both types of contact lenses (p=0.021), but with no difference between them (p>0.05). The mean spherical aberration value did not differ among glasses, toric or soft spherical contact lenses (p>0.05). The mean coma aberrations were high with both types of contact lenses (p=0.041); no difference was observed between the two lens types (p>0.05). Discussion: In this study, it was demonstrated that in cases of low astigmatism, soft spherical and toric contact lenses increase visual acuity, total higher-order aberrations, and coma aberrations, but decrease high-frequency contrast sensitivity. There was no difference between the two types of contact lenses. [ABSTRACT FROM AUTHOR]

Objective: There is shortage of knowledge about medical problems in adolescent skiers. This study aimed to determine frequency of medical signs and symptoms during or after ski among adolescents skiers. Methods: This cross sectional study was performed in 12 consecutive weekends in winter 2005 at Dizin ski resort in Iran. All adolescent skiers (<16years) who had entered the resort during this time period were enrolled in the study. A questionnaire including demographics, duration of transport to the resort, wearing glasses and contact lenses for medical and non medical applications, duration and frequency of skiing and development of signs and symptoms of ski sickness during or after skiing was filled for each participant. In addition, association of mentioned variables with medical problems was investigated. Findings: Of 162 skiers, 111 subjects (68.5%) were males. The mean age of the participants was 14.7±2.1 years. Of them, 1 2 7 skiers wore glasses or lens during skiing. Visual disorders including myopia, hyperopia and astigmatism were found in 24 (14.8%) skiers. Our study showed that the frequency of main ski-related signs and symptoms varies from 0 to 10.5%. There was significant association between occurrence of signs and symptoms and presence of visual disorder (P=0.015). Conclusion: Our results showed that development of ski-related signs and symptoms is relatively frequent. These signs and symptoms have association with minor ophthalmologic problems such as myopia or astigmatism. [ABSTRACT FROM AUTHOR]

Purpose: To assess topography-assisted corneal wavefront excimer laser surface ablation for the correction of ametropia and irregular astigmatism after keratoplasty. Setting: Department of Ophthalmology, St. Thomas'' Hospital, London, United Kingdom. Methods: In this pilot study, 15 patients (16 eyes) who were intolerant of spectacle and contact lens correction due to astigmatic anisometropia after keratoplasty (15 penetrating and 1 lamellar) had topography-assisted customized excimer laser treatments. Corneal topographic data using a Keratron Scout, Placido disk system allowed for preoperative analysis of wavefront anomalies of the anterior corneal surface from which a customized excimer laser correction of both lower-order aberrations (LOAs) and higher-order aberrations (HOAs) was prepared (ORK software) for treatment with a Schwind Esiris flying-spot laser. All eyes had laser-assisted subepithelial keratectomy (LASEK) using 15% alcohol with a 20-second to 30-second application. Four eyes received an application of mitomycin-C (MMC) 0.2 mg/mL for 1 minute after stromal ablation. Results: The mean preoperative spherical equivalent (SE) was −3.50 diopters (D) ± 3.97 (SD) (range +1.625 to −9.25 D). The preoperative cylindrical error was −7.2 D (range −2.75 to −13.5 D). The programmed laser correction was −3.14 D (range +1.62 to −9 D) with a maximum attempted cylindrical correction of −7 D. Adherent LASEK epithelial flaps along suture lines and the graft–host junction were noted in 9 eyes (56%), although it was possible to obtain and replace a partial flap. A follow-up of 18 months was achieved in all eyes. At the final follow-up visit, the mean postoperative SE was −1.08 ± 1.85 D (range +3 to −4.78 D) (P<.01, F<.01). Ten eyes (62.5%) were within ±1 D of the intended correction. The mean postoperative cylindrical error was −2.72 D (range −0.5 to −6.5 D) (P<.001), with vector analysis demonstrating a mean 6.23 D correction. Analysis of HOAs using a 6.0 mm pupil size demonstrated a significant reduction of higher-order root mean square (RMS) (P<.002), trefoil (P<.005), and 4th-order spherical aberration (P<.02) at 18 months compared with preoperative values. Uncorrected visual acuity improved in all eyes (P<.0001). Best spectacle-corrected visual acuity was unchanged or improved in 13 eyes (81%) and worse in 2 eyes by 1 line; 1 eye lost 3 lines due to an increase in preexisting cataract. In eyes that did not receive MMC, corneal haze (grade II to IV) was encountered in 3 eyes (27%). One eye required phototherapeutic keratectomy with MMC application at 12 months. Of the 4 eyes treated with MMC, 1 had trace haze and 3 had no detectable haze. There were no reported cases of epithelial instability, ectasia, or graft rejection. Conclusions: Topography-assisted customized LASEK was effective in the correction of postkeratoplasty astigmatism. A significant improvement of both LOAs and HOAs was obtained with good refractive stability for over 18 months. Iatrogenic haze typically occurred but appeared to be minimized with adjunctive use of intraoperative MMC. [Copyright &y& Elsevier]

Aim: To quantify corneal irregularities, to describe the fitting with contact lenses, and to answer the question whether or not contact lenses with a special back surface design could improve visual acuity in patients with pellucid marginal corneal degeneration (PMCD). Methods: 13 eyes were fitted with contact lenses with a special back surface. Videokeratographic data were assessed. The patients were followed up for an average period of 22.2 months. Lens tolerance and corrected visual acuity were evaluated. Results: The mean eccentricity did not exceed 0.7 in all patients. Either the superior or the inferior eccentricity, or both, were negative in all patients. Using Fourier analysis all PMCD sublects showed an increased irregular astigmatism of the anterior cornea. Using Zernike coefficients seven eyes (53.8%) had a higher order aberration root mean square error (HOA RMS error) out of the normal range. The visual acuity with contact lenses improved in all eyes with an average increase of 2.7 lines (maximum eight lines). No serious complications were observed. Conclusions: Quantitative evaluation of videokeratographic data may help to diagnose PMCD and to distinguish PMCD from other ectatic corneal diseases. Contact lenses with a special back surface design can improve visual acuity and lens tolerance. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate a new, rigid gas permeable contact lens fitting technique following penetrating keratoplasty. Methods: For the correction of postoperative anisometropia or astigmatism, a rigid gas permeable, tetra-curve contact lens with an overall diameter of 12.0 mm and a back optic zone diameter of 8.5 mm was fitted in 36 eyes of 33 patients, 7 months after penetrating keratoplasty. The contact lens back optic zone radius was selected using the videokeratography values over the elevated edges of the transplant wound (with the sutures in place). Graft clarity, visual outcome, and corneal topography were evaluated up to 3 years after surgery at intervals of 6 months. Results: Throughout the follow-up period (range 6–36, mean 19.3±sd 11.8 months), all grafts remained clear. Mean contact lens daily wearing time averaged 13.6 (±sd 4.7) hours. Mean best-corrected visual acuity improved from +0.36 (±sd 0.18) LogMAR with spectacles to +0.11 (±sd 0.11) LogMAR with contact lenses (p<0.0001). One patient was excluded from the study due to a lack of motivation and one had an adverse reaction to the stitches. Conclusions: To improve the visual performance following penetrating keratoplasty, the described fitting technique, guided by videokeratography, eased selection of the back optic zone radius of the initial trial lens. The large diameter contact lenses with a tetra-curve design were well tolerated in all patients for more than 13 hours daily. [ABSTRACT FROM AUTHOR]

The study compared the vision, the use and evaluation criteria in a group of students with corrective daily-wear toric contact lenses and disposable toric contact lenses, in order to ascertain which of the two optical systems is more advantageous. We fitted 114 subjects with daily-wear and disposable lenses to be worn for 12 months, one type of lens in one eye and the other type in the fellow eye. The results reveal no significant differences between the two systems in terms of visual acuity attained: both lenses centred well and were comfortable. Nevertheless, the deposits were significantly greater in the daily-wear lenses. The ocular reactions were less with the disposable toric lenses. In conclusion, the disposable lenses led to fewer deposits and less ocular reactions, but are limited in parameters. However, both optical systems were appropriate for correcting for astigmatism, and provided good visual acuity. [ABSTRACT FROM AUTHOR]

Although toric contact lenses have improved in design and development and their use is increasing, further consideration should be given to the alternative methods of astigmatism correction by contact lenses. Much can still be achieved by non-toric lens, both for a wide range of astigmatism and for ease of supply. A number of these alternatives are examined, their advantages and disadvantages reappraised, and the merits of lens correction compared with surgical methods considered. [ABSTRACT FROM AUTHOR]

Abstract: There have been continued improvements in toric soft lens design over the past three decades. Data that we have gathered from annual contact lens fitting surveys demonstrate a commensurate increase in toric lens fitting as a proportion of all soft lenses fitted. The current toric lens prescribing rate (34% of all lenses when cosmetic tints, monovision and multifocal lenses are ignored) is roughly equivalent to the rate that would be achieved if all cases of astigmatism 1.00D or more were fitted with toric lenses. Toric lenses tend to be fitted more to males and prescribed for monthly rather than daily replacement. [Copyright &y& Elsevier]