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Current indications for scleral contact lenses.
Scleral contact lenses have been largely superseded by corneal contact lenses, but they still retain a role as a treatment of choice for a small group of patients who have tried other types of contact lens wear without success and who are not good candidates for surgery. We performed a cross sectional survey of 44 patients attending clinics at Moorfields Eye Hospital who were successful long-term scleral contact lens wearers and reviewed their indications. Twenty-one patients had been fit to improve visual acuity, 20 for therapeutic indications, and three for cosmetic reasons. Scleral lenses were most useful were with patients with ocular surface disorders, such as Stevens-Johnson syndrome, and for visual rehabilitation of patients with grossly irregular corneal topography. All patients were benefiting from scleral contact lens wear, and none had serious complications as a result of the scleral lens wear. We conclude that all ophthalmic departments should have access to these lenses.
The effects of daily wear of rigid gas permeable contact lenses treated with contact lens care solutions containing preservatives on the rabbit cornea.
We evaluated the effects on the rabbit cornea of daily wear of rigid gas permeable (RGP) contact lenses treated with preserved care solutions by measuring concomitant tear lactate dehydrogenase (LDH) activity followed by in vivo tandem scanning confocal microscopy (TSCM). In vivo morphologic changes were confirmed by in vitro scanning electron microscopy (SEM). Two standard commercial RGP lens wetting and soaking solutions from the same manufacturer were tested: solution A with 0.004% benzalkonium chloride (BAK) and solution B with 0.003% chlorhexidine digluconate (CHX) and 0.002% thimerosal. Two experimental PBS-based wetting and soaking solutions were also tested: solution C with 0.005% BAK and 2% hydroxypropylmethylcellulose (HPMC) and solution D with 0.005% BAK without HPMC. Instillation of solution A without contact lens wear caused significant (P < 0.01) increases in desquamation of the superficial corneal epithelium and tear LDH activity compared with control eyes. After 3 weeks of RGP contact lens daily wear (8 hours/day), modified Draize scores of ocular surface lesions on the eyes wearing RGP lenses treated with solution A increased according to the duration of lens wear. Solution B did not produce significant change. With daily wear for 4 days (8 hours/day), RGP lenses treated with solution C and solution D produced increased corneal epithelium desquamation and an increase of LDH activity in tears. These effects were greater with HPMC (solution C) than without HPMC (solution D).(ABSTRACT TRUNCATED AT 250 WORDS)
Therapeutic contact lenses.
Therapeutic contact lenses are useful in a variety of ocular surface disorders. Their efficacy was evaluated in 40 consecutive patients presenting for therapeutic contact lens fitting for pain due to depressed surface disorders (14 patients), raised surface disorders (11 patients), corneal decompensation (7 patients), trauma (5 patients), and disorders of corneal wetting (3 patients). The therapeutic contact lens was successfully fit and worn, with achievement of the therapeutic objective in 37 of the 40 patients. Corneal wetting disorders and corneal decompensation require only intermediate-term contact lens wear. Thus, therapeutic contact lenses are usually effective for relief of pain due to corneal surface disorders.
Ocular inflammation in patients using soft contact lenses.
Soft contact lenses cleaned and stored in thimerosal-containing solutions may produce an ocular inflammatory process and, if untreated, corneal neovascularization. We examined 38 patients who were using soft contact lenses and found that 31 patients had positive ocular provocation test results to a thimerosal-preserved artificial tears solution. Delayed hypersensitivity to thimerosal was demonstrated by positive patch tests in 27 patients. Avoidance of thimerosal and the use of unit-dose sterile saline solutions has resulted in complete resolution of ocular symptoms.
Biocide uptake in contact lenses and loss of fungicidal activity during storage of contact lenses.
PURPOSE: With recent outbreaks of Fusarium keratitis related to contact lens wear, studies were conducted to determine the biocide uptake during lens storage, and the resulting effect on antifungal activity of related products. METHODS: ACUVUE 2 (etafilcon A) soft, hydrophilic contact lenses (group IV) were soaked from 1 hour to 7 days in OPTI-FREE Express and OPTI-FREE RepleniSH multipurpose disinfecting solutions with POLYQUAD (polyquaternium-1) and ALDOX (myristamidopropyl dimethylamine) biocides and multipurpose solutions, Bausch & Lomb ReNu with MoistureLoc (Alexidine), ReNu MultiPlus (polyhexamethylene biguanide [PHMB]), and AMO Complete MoisturePLUS (PHMB). Storage solutions were tested to evaluate the effect of preservative uptake on the residual biocide activity against Fusarium solani. RESULTS: Approximately 30% to 60% of the PHMB and Alexidine were depleted by 6 hours, with comparable loss of antimicrobial activity. Decreasing activity was noted with corresponding decreases in active concentration throughout the course of the evaluation. The POLYQUAD systems retained nearly 100% of the biocide and fungicidal activity and maintained their concentration in the solution. CONCLUSIONS: OPTI-FREE Express and OPTI-FREE RepleniSH multipurpose disinfecting solutions maintained fungicidal efficacy after storage of lenses. The Alexidine- and PHMB-based multipurpose solutions tested showed significant uptake of preservative into group IV lenses, resulting in a decrease in the residual activity of the storage solution. The POLYQUAD systems showed a low uptake of biocide and maintained fungicidal efficacy against F. solani.
Corneal contact lenses. VI. The contact lens edge.
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[ON VARIOUS PROBLEMS OF INTRAOCULAR PRESSURE IN OUTPATIENTS DESIRING CONTACT LENSES. 2. CHANGES IN INTRAOCULAR PRESSURE CAUSED BY CONTACT LENSES].
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[Studies on the therapy of amblyopia by contact lenses. 3. Results of the prescription of contact lenses in children, with special reference to its application in amblyopia].
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[Topographic ophthalmometry and contact lenses. Apropos of 54 cases of keratoconus fitted with contact lenses].
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Ulcerative keratitis among users of contact lenses.
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Disposable extended-wear contact lenses.
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Caution with disposable soft contact lenses.
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A clinical evaluation of frequent replacement contact lenses on patients currently wearing premium reusable daily wear soft contact lenses.
A 3-month clinical investigation was undertaken to evaluate a population of premium reusable daily wear soft contact lens wearers when refitted with soft contact lenses worn on a daily wear schedule and replaced every 2 weeks. In addition to an initial visit, follow-up visits occurred at 2-, 4-, 8-, and 12 weeks. Areas of assessment included vision, lens fitting performance, ocular physiology, subjective comfort and handling responses and lens surface deposits and damage. Of the 51 patients recruited, 50 were successfully trial fit and enrolled. During the course of the investigation, all subjects utilized a multipurpose care regimen without the addition of an enzymatic cleaner. Upon conclusion of the investigation, 75.0 percent of the subjects chose to continue wearing the study lenses on a 2-week frequent replacement basis.
LF-NMR and multivariate data analysis: compression of data to classify hydrogel contact lenses.
Hydrogel contact lenses swollen in viscoelastic artificial tears solution have been studied, measuring transversal relaxation times of water molecules using LF-NMR techniques. Data were processed by classical multiexponential fitting, by principal component analysis and by SLICING, a multi-way analysis method. The reason for using multivariate data analysis was not to obtain a better fitting, but rather more effective data description. The single-sample relaxation curves were projected in a space spanned by the loading curves, and in this space it was simpler to compare data. In particular, it contributed to the description of the variability of motion characteristics of the water molecule 'families' contained in the studied samples. Applying multivariate techniques, we were able to group lenses with different Equilibrium Water Content (EWC) and with the same water content but different compositions. Accordingly, we were able to point out that, if the lenses are swollen first in physiological solution and then in viscoelastic artificial tears solution, hydration characteristics remained unchanged in all the studied samples, except for 38% EWC lenses.
Advanced manual lensometry: a self-learning guide for evaluating multifocal and specialty lenses, progressive lenses, prisms, and rigid contact lenses.
Advanced manual lensometry techniques are required when automated lensometry may not be appropriate for reading special lenses or rigid contact lenses. These advanced techniques are challenging but provide accurate diagnostic and lens verification data. One should never assume that the glasses the patient is wearing match what the doctor prescribed. The prescription should be checked at least once, even when there are no patient complaints. If possible, learn and practice these special procedures under the supervision of an optician or ophthalmic clinical trainer. This will help to verify that you are performing these special techniques correctly.
The evolution in therapeutic contact lenses.
Therapeutic soft contact lenses were first approved in the 1970s, but the variety of available materials and parameters continues to evolve. Currently, the armamentarium of therapeutic contact lenses allows the clinician to select lenses that not only protect the corneal surface but also assist in modulation of the healing process. This article summarizes the available contact lenses, the conditions most amenable to treatment, and the decision-making process that allows optimal selection of a therapeutic contact lens for a specific patient. Many of the hydrophilic soft contact lenses used for cosmetic correction are not approved for therapeutic use but have been used in an off-label manner as therapeutic lenses. Communicating with the patient is important when recommending the use of a therapeutic contact lens, explaining the goals of therapy, warning about the risks contingent upon contact lens use, and determining whether the lens is being used in an off-label fashion. The advances in contact lens technology have opened new options for use of therapeutic contact lenses. With a new generation of high-Dk lenses whose makers promise fewer limiting problems of vascularization and infection, the utility of the older, traditional therapeutic lenses can be enhanced and the more selective application of individual lenses can be permitted. By considering the healing objectives of the particular treatment plan for a specific patient, greater control of the endpoint and timeframe of therapy is now possible.