Contact Lens-intolerant Patients Research Articles

KEYNOTE ADDRESS: Keratoconus management update

Keratoconus is a non-inflammatory, bilateral, asymmetric, progressive steepening and thinning of the central cornea. Classification of the four stages has evolvedwith inclusion of new criterias such as corneal CCT, sphero-cylindric refraction and mean keratometric values. The currentmanagement strategy of this disease has also largely evolved during the past years with the introduction of new medico-surgical options. Corneal cross linking is now indicated in evolving keratoconus, deep lamellar corneal graft (KLAP) have replaced penetrating keratoplasty (decreasing corneal rejection risk), intra-corneal rings are routinely used in contact lens intolerant patients since femtolaser channels are easily performed for their insertion. Indications and contra-indications of these different medicosurgical treatments will be reviewed. However, corneal GP contact lenses remain the primary visual management for keratoconus and play a major role. New designs allow better mechanical alignment but contact lens tolerance is still an issue for some patients. Up-date materials combinations (hybrid lenses, piggy-backing) and others lens types (silicone softs, sclerals...) are interesting alternatives in such cases to obtain a better lens tolerance and they will be presented and discussed. Lens fitting philosophy of GP corneal lenses, scleral lenses and soft silicone lenses will be largely detailed.Indications in the current contact lens strategicmanagement of keratoconus at different stages of the disease including lens fitting after medico-surgical treatments will be presented.Advancements in care of keratoconus and improvements of lens material and designs science will certainly provide a better quality of vision and quality of life for these patients. This presentation, after the recent classification of the four stages of keratoconus,will focus ondifferent lens types fitted in keratoconic eyes. New medico-surgical treatments are part of care of the disease such cross-linking, lamellar corneal graft, intra corneal rings. However, contact lenses keep a major place in visual rehabilitation and their indications and fitting will be reviewed in non-operated corneas and in operated corneas.

Keratoconus: Overview and update on treatment

Keratoconus is a non-inflammatory, progressive thinning process of the cornea. It is a relatively common disorder of unknown etiology that can involve each layer of the cornea and often leads to high myopia and astigmatism. Computer- assisted corneal topography devices are valuable diagnostic tools for the diagnosis of subclinical keratoconus and for tracking the progression of the disease. The traditional conservative management of keratoconus begins with spectacle correction and contact lenses. Several newer, more invasive, treatments are currently available, especially for contact lens-intolerant patients. Intrastromal corneal ring segments can be used to reshape the abnormal cornea to improve the topographic abnormalities and visual acuity. Phakic intraocular lenses such as iris-fixated, angle-supported, posterior chamber implantable collamer and toric lenses are additional valuable options for the correction of refractive error. Corneal cross-linking is a relatively new method of stiffening the cornea to halt the progression of the disease. The future management of keratoconus will most likely incorporate multiple treatment modalities, both simultaneous and sequential, for the prevention and treatment of this disease.

Excimer Laser Phototherapeutic Keratectomy for Keratoconus Nodules

To report the outcomes of contact lens-intolerant patients with keratoconus (KCN) with subepithelial nodules treated with excimer laser phototherapeutic keratectomy (PTK). The charts of all contact lens-intolerant patients with KCN who underwent excimer laser PTK for subepithelial nodules were identified using a computer database and were retrospectively reviewed. Preoperative and postoperative visual acuity and method of correction, surgical treatment, epithelial healing, complications, and KCN nodule recurrence were all analyzed. Fifteen eyes of 15 patients with a minimum follow-up of 3 months were reviewed. Mean follow-up time was 23.1 months (SD +/- 42.5 months, range 3-143 months). In 9 eyes, the epithelial defect healed by postoperative day 3 and all eyes healed by postoperative day 6. There was no infection or corneal melting in any of the eyes. After PTK, 11 patients were refit successfully with rigid gas-permeable contact lenses and 4 wore glasses. Three patients had a recurrence of the KCN nodule at 3, 8, and 23 months postoperatively. One of them had a repeat PTK 23 months after the initial surgery, improving to 20/40 with contact lenses at 55 months postoperatively. Another patient decided to have a penetrating keratoplasty, and the third patient is considering repeat PTK or penetrating keratoplasty. PTK effectively removed KCN nodules without recurrences in most patients and can be a successful modality to improve contact lens tolerance and delay or avoid more invasive surgery.

Intacs for keratoconus

The use of Intacs as a therapeutic modality in contact lens intolerant patients with mild to moderate keratoconus is increasingly gaining acceptance in the ophthalmic community. During the past year we have gleaned significant new information about patients who are appropriate candidates, the location and relative placement of segment sizes and long-term safety and stability after Intacs placement. Another new and exciting development which will make this procedure safer and more commonly acceptable is the use of the femtosecond laser to create the channels to insert the Intacs, which has been described for the first time this year. This technology allows for accurate depth of inserting, improved outcomes and less complications due to superficial placement. New reports about Intacs revision surgery also allows us to retreat many patients who would otherwise have been considered surgical failures. The new advances described this past year will improve outcomes and ultimately contribute to an increase in the amount of physicians performing this procedure and the number of patients requesting it.

Topography-Guided Surface Ablation for Forme Fruste Keratoconus

To evaluate the efficacy of customized surface ablation in cases of forme fruste keratoconus. Prospective noncomparative case series. Eleven eyes of 8 contact lens-intolerant patients with forme fruste keratoconus treated at the Institute of Refractive and Ophthalmic Surgery and the University Eye Clinic Zurich. Topography-guided customized surface ablation by means of a scanning spot excimer laser. Visual acuity, refraction, quality of vision (ghosting), corneal topography including the Zernike parameter Z3. Statistically significant reduction of manifest refractive error, corneal irregularity, and ghosting. The spherical equivalent was reduced by -2.8+/-0.62 diopters (D) (P = 0.0007), the cylinder by 1.34 +/- 0.18 D (P = 0.015), Z3 was reduced by 41% (P<0.001), and all patients had less ghosting compared to their preoperative status. No eye lost > or =1 lines in best spectacle-corrected visual acuity; however, 7 of 11 eyes gained > or = 1 line. Topography-guided surface ablation is a promising option to rehabilitate vision in contact lens-intolerant patients with forme fruste keratoconus.

Implantation of Artisan Toric Phakic Intraocular Lenses for the Correction of Astigmatism and Spherical Errors in Patients With Keratoconus

To evaluate the correction of astigmatism and spherical ametropia in patients with keratoconus through implantation of an Artisan toric phakic intraocular lens (PIOL) (Ophtec, Groningen, The Netherlands). Artisan toric PIOLs were implanted uneventfully in both eyes of three patients with keratoconus with clear central corneas and contact lens intolerance. Best spectacle-corrected subjective visual acuity after lens implantation was unchanged in one eye and improved in five eyes. Spherical equivalent refraction was significantly reduced in all eyes (P=.03). The safety index was 1.49. The implantation of an Artisan toric PIOL may be an alternative for treating astigmatism and myopia in contact lens intolerant patients with keratoconus with clear central corneas. Especially in patients with associated myopia, this procedure is worth considering before planning a penetrating keratoplasty.

Pediatric Ophthalmology in the New Millennium

I can vividly recall a weekend in the early 1970s when I attended my first national ophthalmology meeting. I was in my residency at the University of Wisconsin and had the opportunity to go to the annual spring meeting of the Chicago Ophthalmologic Society. I remember hearing the speakers during the retinal section of the conference describing the new and exciting innovation in their subspecialty, the pars plana vitrectomy. The anterior segment authorities spoke excitedly about the intraocular lens, a radical new solution to the optical problems associated with aphakia. The first soft contact lens had been recently approved for general use, and there were glowing reports about its successful application in previously contact lens-intolerant patients. By that stage of my training, I had already decided on a career as a pediatric ophthalmologist. So it was with great anticipation that I awaited the section of the program devoted to strabismus. The moderator of those lectures began with an acknowledgment of the great advances that had been made in other areas of ophthalmology, and continued with, Actually, we are not doing anything differently in the treatment of strabismus than we were 50 years ago. In spite of (or perhaps inspired by) those remarks, I did indeed become a pediatric ophthalmologist.

Photorefractive Keratectomy for Astigmatism

Excimer laser photorefractive keratectomy, developed to perform radially symmetric ablations to correct myopic or hyperopic refractive errors, was used to perform toric ablations designed to correct cylindrical errors. An expanding slit was used to flatten the cornea in the steep meridian. Four contact lens-intolerant patients underwent this procedure for correction of astigmatism (two patients after penetrating keratoplasty, one patient after corneal ulcer, and one patient with naturally occurring high astigmatism). In each patient, surgery reduced the regular component of the astigmatism; residual irregular astigmatism limited spectacle-corrected acuity in one patient. All patients experienced a shift in spherical equivalent toward hyperopia. Toric ablations with the excimer laser appear to represent a promising strategy for the correction of compound myopic astigmatism that does not rely on creation of deep corneal incisions, excisions, or compression sutures.

Posterior Chamber Intraocular Lens Implantation in the Absence of Capsular Support

To avoid the complications associated with anterior chamber intraocular lenses (IOLs), we have developed a technique for the implantation of a posterior chamber IOL in the absence of capsular support. The IOL is secured in the ciliary sulcus by suturing the haptics to the sclera at the ciliary sulcus inferiorly and to the sclera or iris superiorly. We have used this technique for secondary IOL implantation in 16 contact lens-intolerant patients with aphakia with a mean follow-up of 9 months (range, 5 to 20 months) and in eight eyes at the time of IOL removal. All eyes with secondary implants had equal or improved vision postoperatively; none developed persistent angiographic cystoid macular edema. In the 8 patients with IOL exchange, visual acuity improved in five eyes, remained the same in two, and decreased two lines in one. Suturing of an IOL in the ciliary sulcus has enabled us to use a posterior chamber IOL in eyes without a posterior capsule when secondary IOL implantation or IOL exchange is indicated. Secondary posterior chamber IOL implantation is recommended only when satisfactory vision cannot be achieved with glasses or contact lenses, and further follow-up is needed before this procedure can be widely recommended.