Scleral Contact Lenses for Keratoconus - Dr. Barry Leonard and Associates Scleral Lens Fitting - Dr Barry Lenoard While the visual outcomes are comparable to PK, DALK eliminates the risk of endothelial rejection and steroid-induced secondary glaucoma. This fluid reservoir between the lens and the cornea supports the scleral lens, prevents corneal desiccation, and optically neutralizes aberrations caused by corneal surface irregularities.66,67, Scleral lens fitting: light contact with the sclera, no signs of pressure, Scleral lenses are most commonly used to treat patients with KC that causes high irregular astigmatism. In scleral lens applications, choice of total lens diameter is important for a successful fitting. The rigid center part has a spherical optical zone and a reverse-geometry curve. With their expanding areas of usage and technological advances, modern scleral lenses are candidates to become a successful option for contemporary CL fitting in KC, especially advanced cases. Relevant financial disclosures: Mr. Nuzbrokh and Dr. Rosenberg: None. In addition, implants will not halt the progression of the disease, so while it is an effective treatment option, it is not a cure. The Association between sociodemographic factors, common systemic diseases, and keratoconus: an analysis of a nationwide heath care claims database. What Is It Like Weating Scleral Lenses with Keratoconus? Scleral lens for keratoconus: technology update - PMC With these lenses, there is a fluid layer between the lens and cornea. A number of approaches have been developed to improve the quality of vision in affected patients and, in some cases, to slow or stop disease progression. Today, these problems have largely been overcome by using materials with high oxygen permeability. 13 Park SE et al. 10 Raiskup F et al. Segal O, Barkana Y, Hourovitz D, Behrman S, Kamun Y, Avni I, Zadok D. Scleralcontact lenses may help where other modalities fail. When the study data were evaluated, it was found that tear film break-up time, goblet cell count, and epithelial cell morphology had changed significantly in both groups using CLs compared to those not using CLs. Scleral contact lenses are rigid gas-permeable lens with a large diameter. Penetrating keratoplasty (PK) for KC is an effective procedure with good visual outcomes. Patients may benefit from larger diameter lenses that lie on the white part of the eye (the sclera) and vault over the cornea without touching its surface. Quality-of-Life Improvement After Scleral Lens Fitting in Patients With To assess the visual performance of a mini-scleral lens in patients with keratoconus and to evaluate its fit by optical coherence tomography (OCT). The cone may be round and near-center or oval-shaped and sagging. Our rationale is that we believe flat-fitting lenses lead to increased central irritation, erosions, abrasions and, hence, scarring. To date, various types of CL have been developed and span a wide range, including rigid lenses, soft lenses, lenses that combine the positive qualities of both of these materials, and lenses with custom designs. The rigid part of ClearKone lenses is made of Paragon HDS 100 (Paragon Vision Sciences, Mesa, AZ) gas-permeable rigid material, with a dome (vault) diameter of 7.4 mm and oxygen permeability of 100x10-11 (cm2/s) x (mLO2/[mL x mmHg]). Yildiz et al.43compared the effects of RGPCLs and silicone hydrogel KC lenses (Kerasoft IC and Toris K) on quality of life in keratoconic patients and found that both lens groups had similar quality of life scores determined using the CL Impact on Quality of Life questionnaire. The Beginner's Guide to Fitting Scleral Contact Lenses - Eyes On Eyecare Keratoconus, contact lenses, rigid gas-permeable lenses, soft lenses, piggyback lenses, hybrid lenses, scleral lenses. One reason is that scleral lenses require more measurements to produce the scleral lens to fit correctly in order to improve vision. Although several indices are available to monitor the progression of keratoconus, there is no consensus on which is most reliable.3, Complications. Millodot M, Ortenberg I, Lahav-Yacouel K, Behrman S. Effect of ageing on keratoconic corneas. Before now, Optometrists fitted patients for scleral Keratoconus contacts through a process . A comparison of Synerg Eyes versus traditional rigid gas permeable lens designs for patients with irregular corneas. They concluded that Toris K lenses are a good alternative for keratoconic patients who are unable to tolerate RGPCLs. ODonnell C, Maldonado-Codina C. A hyper-Dk piggyback contact lens system for keratoconus. Purpose: To investigate the success and failure of scleral lens fitting in patients with keratoconus with resolved hydrops. Pullum KW, Stapleton FJ. The result is clear, crisp, stable vision. Contact Lenses for Keratoconus | SpringerLink Forme fruste keratoconus (subclinical KC) is an early, asymptomatic form of the disease with no apparent clinical signs; it can be diagnosed only through analysis of corneal morphology.3, Pellucid marginal degeneration (PMD) is a bilateral, noninflammatory ectatic disorder similar to KC. Custom-designed scleral lenses help patients with corneal irregularities achieve dramatic improvements in visual acuity and comfort. The site is secure. Negishi K, Kumanomido T, Utsumi Y, Tsubota K. Effect of higher-order aberrations on visual function in keratoconic eyes with a rigid gas permeable contact lens. Nau AC. The following maps are analyzed: anterior, sagittal, and tangential curvature maps; anterior and posterior elevation maps; and the thickness map.4. The "A B C's" of Contact Lens Fitting for Keratoconus Bozkurt et al.36used corneal topography and noncontact endothelial microscopic data to investigate changes in endothelial density in different stages of KC and determined that endothelial cell count decreased with KC progression. Scleral lenses vault over the cornea and rest on the sclera while avoiding the diseased cornea. KeraSoft IC lenses are prism-ballasted, silicone hydrogel (Folcon V3, 74% water content) lenses with an aspheric toric front surface and aberration control. 2 Bialasiewicz A, Edward DP. Kymes SM, Walline JJ, Zadnik K, et al; Collaborative longitudinal evaluation of keratoconus study group. Safety and Efficacy of Scleral Lenses for Keratoconus - PMC Godefrooij DA, de Wit GA, Uiterwaal CS, Imhof SM, Wisse RP. Mini-scleral lenses can be made thinner, which provides an advantage in terms of oxygen permeability. One of the benefits of the cKlear Method, aside from providing our patients with clear vision, is a 52% first-fit success and an 85% second-fit success rates (compared to about 25% to 30% first-fit success and up to 3 or 4 visits for traditional scleral lens fitting methods). Fernndez-Velzquez FJ. The impact of the Boston ocular surface prosthesis on wavefront higher-order aberrations. Conflict of Interest: No conflict of interest was declared by the authors. They also stated that surgical methods such as intracorneal ring segment or phakic intraocular lens implantation can be used to treat patients who are unable to use CLs and that lamellar or full-thickness corneal transplantation may become necessary in case of extreme corneal thinning or scarring, but these surgical interventions can often result in temporary inflammatory responses and permanent sequelae.17, CL fitting is a long and arduous process for both the patient and the practitioner, and the three main goals of this process are to achieve optimal comfort, increase vision quality, and provide the best possible fit for the irregular corneal structure. Many patients report high levels of satisfaction with their vision and comfort when wearing scleral lenses. Objectives: To assess the visual performance of a mini-scleral lens in patients with keratoconus and to evaluate its fit by optical coherence tomography (OCT). Hwang JS, Lee JH, Wee WR, Kim MK. In conclusion, although HCLs are a product of advanced technology that combines the positive qualities of rigid and soft materials in a single lens, more research is needed on the effects they may have on the cornea and ocular surface in the long term. Inserting scleral lenses for Keratoconus-My entire process Kosaki R, Maeda N, Bessho K, Hori Y, Nishida K, Suzaki A, Hirohara Y, Mihashi T, Fujikado T, Tano Y. 7 strategies for fitting keratoconus patients - Optometry Times A study investigating the visual success and reliability of Toris K lenses of 50 keratoconic patients (64 eyes), Sultan et al.41reported that best corrected visual acuity (BCVA) was significantly better with Toris K lenses compared to spectacles but did not differ statistically between RGPCLs and Toris K lenses. Lecture fees or honoraria, travel fees or reimbursements when speaking at the invitation of a commercial company. 2013;20(1):3-4. Recovery takes several weeks to months, with visual function stabilizing up to one year after surgery. Such hard contact lenses are referred to as scleral lenses. The eye must be free of scars, herpetic infection, autoimmune disease and wound healing . Nomenclature for scleral lenses is undergoing development. When applying the PBCL system, many researchers prefer positive-powered (+0.50 to +4.0) soft CLs due to their steeper front surface curves for better stabilization of the rigid lens.55,56,59, Fluorescein pattern of piggyback contact lens fitting: slight pooling at the center, a fluorescein-free zone in the periphery, and thin fluorescein accumulation at the lens edge. Find The Right Fit For Keratoconus - reviewofcontactlenses.com 8 Gomes JA et al. Fernandez-Velazquez FJ, Fernandez-Fidalgo MJ. Contact Lens Spectrum - Scleral Contact Lens Fitting Guide Depending on the severity of keratoconus, patients may need to wear contacts to further correct their eyesight after implants. Several studies have shown that adverse effects at the cellular and molecular level may occur on the ocular surface and tear film layer of patients who use soft or rigid CLs compared to those who do not use CLs.29,30In their study of the effects of rigid and soft lenses on the ocular surface, Pisella et al.30demonstrated the presence of subclinical inflammation in asymptomatic CL users, although at a lower level in soft CL users than in rigid CL users. Relationship between corneal topographic indices and scleral lens base curve. Age-specific incidence and prevalence of keratoconus: a nationwide registration study. KC is a complex disease with a multifactorial etiology, likely encompassing both genetic and environmental factors. Keratoconus (KC) is a progressive disease that leads to major losses of visual quality and related quality of life. Contact lens in keratoconus - PMC - National Center for Biotechnology Cont Lens Anterior Eye. Today, RGPCLs remain the first-line treatment for KC because they are practical and safe lenses with high optical success when applied in consideration of the many facets of KC. Advanced anterior segment imaging in keratoconus: a review. Fitting Scleral Lenses in Keratoconus Patients - Contact Lens Spectrum Surv Ophthalmol. Andreanos KD, Hashemi K, Petrelli M, Droutsas K, Georgalas I, Kymionis GD. These lenses are also indicated for keratoglobus, penetrating keratoplasty, pellucid marginal . On the other hand, it was determined that interleukin-6, tumor necrosis factor -alpha, ICAM-1, and VCAM-1 levels were elevated in the tears of KC patients using RGPCLs and that this increase was even greater in patients with advanced KC.32Similar studies on KC patients reported an increase in lacrimal proinflammatory cytokine expression, and noted that changes in the concentration and dynamics of these mediators may influence the progression of the disease.33,34Bitirgen et al.35detected a decrease in basal epithelial cells and anterior stromal keratocyte density in corneas affected by KC, but reported no change in posterior stromal keratocyte density, endothelial cell count, or subbasal corneal nerve morphology. Only eyes fit successfully with scleral contact lenses for 1 year were included. In summary, with the bandage effect provided by the soft lens, the PBCL system is currently a successful and reliable method that can be used in KC patients to protect the corneal surface from mechanical effects, provide better stabilization of the RGPCL on the irregular cornea, and improve CL tolerance. Special designs and a toric back surface in large scleral lenses may help prevent sectoral pressure, bubble formation, tear exchange, conjunctival prolapse, and lens decentration and distortion.74, Scleral lenses consist of 3 zones: The scleral (haptic) zone that rests on the sclera, the dome (vault) that provides corneal and limbal clearance, and the optical zone. Scissoring of the red reflex on retinoscopy is a reliable and sensitive method for detecting early-stage KC. Wagner H, Barr JT, Zadnik K. Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study: methods and findings to date. Rosenthal P, Croteau A. Fluid-ventilated,gas-permeablescleralcontact lens is an effective option for managing severe ocular surface disease and many corneal disorders that would otherwise require penetrating keratoplasty. Toris K 12 (central thickness: 0.45 mm) can be used by patients with grade 1-2 KC, while Toris K 34 (central thickness: 0.52 mm) can be used by patients with grade 3-4 KC (Figure 5). In conclusion, although there has been important progress toward combining comfortable wear and visual performance with soft KC lenses, it seems that this goal has not been entirely achieved and that the search in this field will continue. PMD is characterized by inferior corneal thinning, typically in a band-line area concentric to the limbus on slit-lamp evaluation and a crab-claw appearance on topography.7, Keratoglobus is a corneal thinning disorder characterized by global thinning and protrusion. Gomes JA, Tan D, Rapuano CJ, Belin MW, Ambrsio Jr R, Guell JL, Malecaze F, Nishida K, Sangwan VS; Group of Panelists for the Global Delphi Panel of Keratoconus and Ectatic Diseases. Toris K lenses have a toric front surface and provide dynamic stabilization. 2. Success of hydrocone (TORIS-K) soft contact lens for keratoconus and traumatic keratopathy. Unilateral KC has been described at rates of 0.5-4.5%, but with current topography and corneal aberration measurement techniques, it has been reported that changes that may be associated with subclinical KC can also be detected in the apparently normal fellow eye.1Age of onset is in the early teens or twenties, with progression continuing until the third or fourth decade, and the rate of progression varies among individuals.2KC is classified as mild, moderate, or severe based on ocular signs and symptoms. Biochemical instability leading to central or paracentral stromal thinning has been attributed to an imbalance between proteolytic enzymes and proteinase inhibitors.3. Schornack MM, Patel SV. Soft and hard contact lenses worn in combination. 2017;30(2):110-124. In order to prevent symptoms of corneal hypoxia and edema in scleral lens wearers, it is recommended to use scleral lenses up to 200 m thick and made from high-Dk material (>125 Barrer) fitted with a clearance less than 150 m.83, Scleral lenses have improved significantly in recent years in terms of their material properties, design, and production methods.79PROSE, formerly known as Boston scleral lens, Boston scleral lens prosthetic device, or Boston ocular surface prosthesis, is a customized lens with computer-assisted design. It is believed that the high-Dk materials and thin designs of modern scleral lenses will eliminate this hypoxic effect in the cornea, but there is no evidence demonstrating this definitively. Despite the optical success of RGPCLs, lens intolerance resulting from irritation to the eyelid and anterior surface of the cornea due to their rigidity necessitates the use of soft lenses by some patients. The larger diameter also ensures that the lens will not become dislodged during regular wear, even for people with an active lifestyle and advanced keratoconus. Rathi VM, Mandathara PS, Taneja M, Dumpati S, Sangwan VS. Scleral lens for keratoconus: technology update. Assessing Scleral Contact Lens Satisfaction in a Keratoconus Population. This treatment aims to stabilize the structure of the cornea. The onset of KC typically occurs around the second decade of life, with the disease progressing slowly thereafter and ceasing in most patients by the fourth decade. Topographic maps will show irregular astigmatism with steepening. This task is particularly challenging in keratoconus patients and often requires a personally-tailored approach. However, it was also reported that patients who use CLs have the highest quality of life scores.13,14,15, The process of increasing vision quality in KC patients is usually complex and closely associated with the rate of disease progression. The minimally-invasive, advanced therapy slows down or stops the progression of the corneal deformation of keratoconus, by making collagen bonds in the cornea stronger, allowing it to become stiffer and usually stop bulging out. However, soft contact lenses (SCLs) transfer corneal anterior surface irregularities to their own front surfaces and thus have low visual success rates. To do so, one of three criteria must be met: abnormal posterior corneal ectasia, abnormal corneal thickness distribution (rate of change of corneal thickness across the corneal tissue) and/or clinically non-inflammatory corneal thinning. Moon et al.31compared myopic patients and KC patients using RGPCLs with KC patients not using CLs and a normal control group in terms of ocular surface and tear film changes. On the other hand, a study by Sengor et al.55showed that a large majority of patients were able to wear their rigid lenses without a soft lens after a mean of 6 months (3-12 months), which was attributed to reduced sensitivity and habituation over time.
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