Amiodarone keratopathy and rigid contact lens wear.

Two cases are presented of patients wearing rigid gas permeable contact lenses who exhibited the typical fan-shaped patterns of corneal pigment deposition related to long-term medication containing amiodarone. The vortex corneal epitheliopathy and contact lens tolerance were monitored over several years. In both cases, the lens material was replaced with one incorporating an ultra-violet light inhibitor in view of the possibility of medically induced photosensitivity.

Contact lens fitting in high degree myopia.

Advantages and disadvantages of both spectacle and contact lens correction of high degree myopia are reviewed. Pertinent aftercare problems in this group of patients are discussed. Aspects of contact lens wear with regard to the eyelids are described. Soft contact lens problems are discussed in relation to the greater thickness of lenses of high power. Guidelines are provided for the fitting of rigid gas permeable and of soft contact lenses for this patient group. Other factors are explored in lens fitting such as over-refraction, near vision and practitioner costs. Recommendations are given for advising on lens care and aftercare.

The use of occluding tinted contact lenses.

PURPOSE: We explored the clinical issues surrounding the use of tinted contact lenses for vision occlusion in cases of debilitating vision disturbance, such as intractable diplopia. METHODS: We report the results with four patients fit with occluding tinted contact lenses. RESULTS: Vision occlusion by contact lenses provided a suitable comfortable occlusion method with improved cosmesis compared to occlusion by spectacles. Lens parameters and tint specifications were ordered for each patient. Correct lens care and handling were necessary to avoid contact lens related ocular inflammation. CONCLUSION: Provided that lens care is satisfactory and the patient does not have unreasonable expectations, a tinted contact lens can be a useful alternative to a covered spectacle lens or eye patch when occluding one eye, such as in cases of intractable diplopia, severe vision distortion, or intolerable photophobia.

Contact lens fitting after photorefractive keratectomy.

AIMS/BACKGROUND: This study evaluated contact lens fitting and the longer term response of the photorefractive keratectomy (PRK) cornea to lens wear. In PRK for myopia problems such as regression, anterior stromal haze, irregular astigmatism, halo aberration, and anisometropia have been reported. Certain patients therefore require contact lens correction to obtain best corrected visual acuity (BCVA). METHOD: From an original cohort of 80 patients, 15 were dissatisfied with their visual outcome 6 months after PRK. Ten of these were fitted with lenses and monitored regularly. RESULTS: The best fit rigid gas permeable lens of diameter 9.20-10.00 mm was generally 0.10 mm steeper than mean keratometry readings. Because of lid discomfort five patients were refitted with daily wear soft lenses. All 10 achieved satisfactory lens wear of 10 hours per day. Central corneal steepening of 0.75 D (0.15 mm) occurred in one patient. Two patients had slight central corneal flattening. Three patients discontinued lens wear as they found lens care a nuisance. Four finally opted for retreatment by PRK. CONCLUSIONS: In most cases, contact lenses gave good visual acuity and, in cases of mild irregular astigmatism, a significant improvement over spectacle BCVA. No significant adverse reaction to contact lens wear was found. Although ocular tolerance of lenses was satisfactory, several patients discontinued lens wear or sought improved unaided vision.

Contact lens fitting after photorefractive keratectomy: a comparison of two groups of patients.

From a research programme comparing two photorefractive keratectomy (PRK) methods, Group S using Summit ExciMed UV 200, and Group V using the VisX 20:20 excimer laser system, 10 patients from each group were recruited. They were referred 6-12 months post-PRK for lens fitting to correct resultant ametropia or irregular astigmatism. Ablation zone diameters were: Group S, 4.5 mm; Group V, 4-6 mm. For Group S, best fit rigid gas permeable (RGP) lenses generally had a back optic zone radius (BOZR) 0.10 mm steeper than the mean keratometry reading (K) and overall diameter of 9.20-10.0 mm. For Group V best fit RGP lenses generally had a BOZR of 0.20 mm steeper than the mean K. The lenses often required large diameters to improve lens centration and extra negative power to compensate for the positive power of the central tear pool. Several patients required soft lens fitting to improve comfort and some finally opted for repeat PRK.

The long-term use of the SoftPerm lens on pellucid marginal corneal degeneration.

Pellucid marginal corneal degeneration (PMCD) is a corneal degeneration often confused with keratoconus because of the presence of high regular and irregular astigmatism. Vision correction can be achieved with rigid contact lenses, but the asymmetric topographic profile often makes obtaining a stable lens fit difficult. This study describes the fitting and satisfactory daily wear during 4 years of a combination lens design (2 years Saturn II and 2 years SoftPerm) on a patient with PMCD. The lens consisted of a central rigid gas permeable portion surrounded by a soft hydrophilic "skirt." Although the degree of astigmatism was high, 1.6 mm (8.00 D) by keratometry and 12.00 D by refraction, the patient was able to wear the lens comfortably 12 hours per day and achieve visual acuity of 20/20. Routine keratometry, pachymetry, and slit lamp examination showed no significant corneal changes resulting from lens wear.

Keratoreformation by contact lenses after radial keratotomy: a re-analysis.

A recent paper analysed change in refraction and corneal curvature associated with contact lens wear in patients who had had radial keratotomy at least a year beforehand. Conventional methods of analysis were used. This paper applies methods that have only recently become available. The results are clearer and less ambiguous. Formally, the analysis shows that there are significant mean changes in refraction (estimated to be +1.69/-0.50 x 105) and corneal power (-0.66/-0.25 x 155). In spite of the difference between these two mean changes, the analysis shows that the change in refraction may be associated with change in the corneal power alone. There is no reason to believe that any other change is occurring in the eye. Care needs to be executed in assigning a causative role to contact lenses in changing refraction and corneal curvature. Almost certainly the lenses do have such a role but the analysis does not formally allow an unequivocal conclusion concerning that role.

Keratoreformation by contact lenses after radial keratotomy.

Since the number of patients undergoing radial keratotomy has increased, more have required contact lens fitting to correct residual ametropia. A number of practitioners suggest that the postoperative changes stabilize after 12 months, so contact lens fitting on the unusual resultant corneal topography can begin. This paper discusses corneal and refractive changes that are revealed even when correctly fitting lenses are worn 1-5 years postoperatively. These changes indicate that lens wear may influence corneal topography and refraction even several years after radial keratotomy.

Alternatives to toric contact lens fitting--for regular and irregular astigmatism.

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.