Piggyback Lens Research Articles

Management of Keratoconus With Corneal Rigid Gas-Permeable Contact Lenses.

Vision correction using a corneal rigid gas-permeable contact lens, which is relatively safe, easy to replace, and economical, is still the basis of the management for keratoconus. For eyes with keratoconus, two fitting strategies have traditionally been used in Japan: apical touch fitting with spherical lenses and parallel fitting with multicurve lenses. These two techniques have different success rates depending on the type and severity of keratoconus. Therefore, it is important to classify eyes with keratoconus into four types according to the shape of the cornea and select the prescription techniques according to this classification. If the corneal GPs prescribed by these fitting methods cannot be used because of mechanical irritation to the corneal epithelium, the "piggyback lens system" is an effective option. Furthermore, proper lens care must be instructed to patients to prevent contact lens-related complications and maintain visual function. If these fittings and introductions can be performed properly, corneal GPs can safely provide effective and comfortable vision for many patients with keratoconus, even for those with severe keratoconus.

Application of piggy-back lens in the correction of severe keratoconus: A case study.

This is a case study on the application of a piggy-back lens in the correction of severe keratoconus. From the results of general eye examination, refractive state examination, and corneal morphology examination on the patient, it was determined that corneal protrusion and deformation of the right eye were obvious. The right eye was corrected using a piggy-back lens and the left eye with a rigid gas-permeable contact lens (RGPCL) alone. The right-eye lens fit well and the lens coverage was good. Both the static and dynamic fit results for the left-eye lens were good. After wearing the glasses for one month, the patient attended a review and stated that the lenses were comfortable to wear. The patient's vision was good after wearing the lenses. No obvious congestion was found in the conjunctiva under a slit lamp. The effects on both eyes of wearing RGPCLs were favorable. The corneal curvature reduced and the corneal thickness only changed to a small degree. For keratoconus patients, application of a piggy-back lens can improve corrected visual acuity, comfort levels, and safety, prolong the wearing time, and enhance the effect of orthokeratology.

Visual Rehabilitation With Contact Lenses Following Open Globe Trauma.

To describe visual outcomes with various contact lens modalities in patients with a history of ocular trauma who underwent surgical open globe repair. Records of all patients with a history of open globe injury and repair at a tertiary care hospital between January 1, 2010, and December 31, 2016, were reviewed. Demographics, type of injury, and visual acuity were assessed before and after contact lens evaluation. Of 214 patients who underwent open globe repair, 29 (13.6%) were evaluated with a contact lens. Visual acuity improved in 97% (28 of 29) of patients from 1.47±0.75 to 0.67±0.71 logarithm of the minimal angle of resolution (logMAR) with manifest refraction to 0.28±0.45 logMAR with contact lenses (n=29; P<0.0001). Corneal opacity was the most common clinical indication (20 of 29) for fitting followed by aphakia (13 of 29). A range of contact lens modalities, including corneal rigid gas-permeable (12 of 28), soft (9 of 28), hybrid (3 of 28), scleral gas-permeable (2 of 28), and piggyback (2 of 28) lenses were prescribed. In this study, patients with a history of trauma and open globe repair with good neurosensory visual potential had improvements in visual acuity with contact lens greater than manifest refraction. Soft and gas-permeable lenses were used to improve visual acuity in patients with a history of open globe repair and corneal scarring, aphakia, iris abnormalities, or other ocular sequelae. Although corneal rigid gas-permeable lenses were prescribed most often, additional consideration should be given to other contact lens modalities, including soft, piggyback, hybrid, and scleral gas-permeable lenses.

Assessment of a new hydrophilic acrylic supplementary IOL for sulcus fixation in pseudophakic cadaver eyes.

PurposeManagement of refractive errors after cataract surgery includes spectacles or contact lens, secondary laser vision correction, intraocular lens (IOL) exchange, or piggyback lens implantation. We evaluated for the first time a single-piece hydrophilic acrylic IOL designed for supplementary sulcus fixation in postmortem pseudophakic human eyes.MethodsPseudophakic human cadaver eyes were imaged by anterior segment optical coherence tomography (AS-OCT) to assess position of the primary IOL. Eyes were prepared as per the Miyake-Apple technique. The supplementary IOL (Medicontur A4 Addon IOL family) was then inserted into the ciliary sulcus. AS-OCT and photographs from anterior and posterior views were used to assess IOL centration, tilt, and interlenticular distance from the primary IOL.ResultsData were obtained from 12 eyes having primary IOLs of varying materials and designs in the bag and representing different sizes of eyes and severity of Soemmering's ring formation. The A4 Addon IOL was successfully inserted into the ciliary sulcus and was well centered in all cases. Four cases of tilt were observed on AS-OCT: three with mild tilt due to pre-existing zonular dehiscence, and one due to a localized area of Soemmering's ring formation. Interlenticular distance ranged from 0.34 to 1.24 mm and was not dependent on severity of Soemmering's ring or type of primary IOL.ConclusionsThe A4 Addon IOL was designed for sulcus fixation as a supplementary lens, with a large diameter, a square-shaped optic, four smooth loop haptics, and a convex-concave optical surface. It exhibited appropriate centration and interlenticular distance with different primary in-the-bag IOLs.

Prevention and correction of residual refractive errors after cataract surgery

Cataract surgery today has become more of a refractive surgery with high patient expectations and demand for independence from glasses. With advances in biometry, precise intraocular lens (IOL) power calculation is the most important step in achieving desired target refraction. Noncontact optical biometry has become the gold standard worldwide with a few exceptions where contact ultrasound biometry still needs to be performed. Although there is no single formula for IOL power calculation suitable for all eyes, our understanding of which formulae to use in specific situations is much better. Despite advances in biometry and cataract surgery techniques, unsatisfactory visual and refractive outcomes occur occasionally. Enhancement after cataract surgery is required in these cases. The common methods to treat such cases are corneal-based laser refractive surgery or lens-based procedures such as piggyback IOL and lens exchange.

Piggyback Lens System in the Management of Keratoconus

A review of literature on the use of Piggyback contact lens system in the management of Keratoconus. Factors discussed included the oxygen transmission through the dual lens system, lens material, cost, and rate of contact lenses related complications. One the most important raised questions are: does this lens system fulfill the definite goal in the management of Keratoconus which is best optical correction along which least corneal insult.

Surgical options for correction of refractive error following cataract surgery.

SummaryRefractive errors are frequently found following cataract surgery and refractive lens exchange. Accurate biometric analysis, selection and calculation of the adequate intraocular lens (IOL) and modern techniques for cataract surgery all contribute to achieving the goal of cataract surgery as a refractive procedure with no refractive error.However, in spite of all these advances, residual refractive error still occasionally occurs after cataract surgery and laser in situ keratomileusis (LASIK) can be considered the most accurate method for its correction. Lens-based procedures, such as IOL exchange or piggyback lens implantation are also possible alternatives especially in cases with extreme ametropia, corneal abnormalities, or in situations where excimer laser is unavailable. In our review, we have found that piggyback IOL is safer and more accurate than IOL exchange.Our aim is to provide a review of the recent literature regarding target refraction and residual refractive error in cataract surgery.Electronic supplementary materialThe online version of this article (doi:10.1186/s40662-014-0002-2) contains supplementary material, which is available to authorized users.

Predicting scleral GP lens entrapped tear layer oxygen tensions.

Over the past decade, utilization of scleral gas permeable (GP) contact lenses has steadily increased. Scleral GP lenses offer yet another option for patients suffering from visually debilitating corneal and tear conditions. Oxygen delivery to the cornea in the presence of a contact lens system continues to be a subject of interest, and scleral GP lenses are no exception. This paper utilizes an existing model based on simultaneous two lens systems (piggyback lenses) as a resistance to oxygen in series, and applies this model to scleral GP lens systems. Theoretical oxygen tensions are calculated for tear layers trapped beneath scleral contact lens systems and the anterior corneal surface with a simple single chamber corneal model using a computer software spreadsheet. Only the best case scenario for current scleral gas permeable lenses (thickness and Dk)/tear layer values allow sufficient tear layer oxygen tension (approximately 100 mmHg) to preclude corneal hypoxia. The results of the spreadsheet model suggest that clinicians would be prudent to prescribe scleral GP lenses manufactured in the highest Dk materials available and to fit without excessive corneal clearance to minimize anterior segment hypoxia.

Patient comfort following thirty minutes of lens wear: piggy-back versus conventional rigid-lens wear

Discomfort when wearing contact lenses, especially rigid contact lenses, is a common complaint amongst neophyte as well as experienced contact lens wearers. Wearing a piggy-back system of contact lenses has been shown to improve comfort and wearing time, especially in keratoconic subjects. Twenty two normal subjects wore a rigid lens or a piggy-back system of lenses for thirty minutes and after a thirty minute break swopped the mode of lens wear and wore the second modality for a thirty minute period. This study suggests that a piggy-back lens system provides improved comfort compared to wearing a rigid lens on its own. The order of lens wear might, however, influence the perceived comfort.

Soft contact lens fitting after intrastromal corneal ring segment implantation to treat keratoconus.

To assess the feasibility of fitting a lathed soft toric contact lens (STCL) after the implant of intrastromal corneal ring segments (ICRSs) to treat keratoconus. Six months after ICRS implantation, 47 eyes of 47 patients (18-45 years) were fitted with a STCL. In each eye, we determined refractive error, uncorrected (UDVA) and corrected distance visual acuity (CDVA), and keratometry and asphericity measures. The outcome of STCL fitting was defined according to CDVA as successful (≤0.2logMAR) or unsuccessful (>0.2logMAR). Patients in the unsuccessful group were refitted with a piggy-back (PB) system. The above variables and the change in CDVA observed after STCL and PB lens fitting from spectacle CDVA were compared in the two groups. STCL fitting was successful in 75%, 66.66% and 0% of the ICRS implanted eyes with stages I-III keratoconus, respectively. Spectacle-CDVA was 1.5 lines better and mean corneal power was 3.62D lower in the successful STCL group. In this group, the difference in cylinder axis between spectacles and STCL was 24.25° lower. PB refitting achieved a PB-CDVA ≤0.2logMAR in all cases. A similar difference in the CDVA change achieved by contact lenses versus spectacles was observed in the successful STCL and PB refitted groups. STCL fitting is a feasible option in a large proportion of patients implanted with ICRS. When these lenses are unsatisfactory, a PB system is a good alternative.

Management of residual refractive error after cataract surgery.

To provide a review of the recent literature on the management of residual refractive error after cataract surgery. Laser in-situ keratomileusis (LASIK) is the most accurate procedure to correct residual refractive error after cataract surgery. Lens-based procedures, such as intraocular lens (IOL) exchange or piggyback lens implantation, are also possible alternatives in cases with extreme ametropia, corneal abnormalities, or in situations where excimer laser is not available. In this review, we found that Piggyback IOL were safer and more accurate than IOL exchange. Emmetropia is our main target today in modern cataract surgery. Accurate biometric analysis, selection and calculation of the adequate IOL, and modern techniques for cataract surgery all help surgeons to move toward the goal of cataract surgery as a refractive procedure free from refractive error. However, in spite of all these inputs, residual refractive error still occasionally occurs after cataract surgery and LASIK seems to be the most accurate method for its correction.

Management of post-LASIK keratectasia with a piggyback contact lens system

Purpose: This case report highlights the clinical challenges involved in the management of a patient with post-LASIK keratectasia and reviews the various treatment options for iatrogenic keratoconus. A single case is presented with a focus on contact lens fitting and management of concurrent ocular surface disease.Although the patient was successfully fitted with large diameter corneal gas permeable lenses, the interference of pre-existing atopic disease combined with post-LASIK dry eye induced a compromised ocular surface requiring a therapeutic bandage piggyback lens. A review of the literature indicates that current screening methods prior to refractive surgery have made improvements for detecting patients at higher risk of serious complications. However, as this case illustrates, previous guidelines were inadequate in identifying incipient keratoconus. Possible treatment options for iatrogenic keratoconus, one of the most severe refractive surgery complications, include contact lenses, intrastromal corneal ring segments, corneal cross linking, and keratoplasty. This case report demonstartes that post- LASIK keratectasia with concurrent ocular surface disease can be successfully managed with the use of a piggyback contact lens system.

OCT imaging of the anterior eye

OCT imaging of the anterior eye

Novel diagnostic methods for the assessment of the anterior eye

Novel diagnostic methods for the assessment of the anterior eye

Resolving Refractive Error After Cataract Surgery: IOL Exchange, Piggyback Lens, or LASIK

To evaluate the efficacy, predictability, and safety of three different procedures (intraocular lens [IOL] exchange, piggyback lens implantation, and LASIK) to correct residual refractive error following cataract surgery. A retrospective multicenter study comprised 65 eyes of 54 patients that underwent phacoemulsification, resulting in a unacceptable final refractive error. Eyes were divided into three groups: eyes that had an IOL lens exchange (17 eyes), eyes that had a piggyback lens implanted (20 eyes), and eyes that had LASIK (28 eyes). No differences between the IOL exchange and piggyback lens groups in the spherical equivalent, sphere, or cylinder were found (P = .072, .436, and .081, respectively). The LASIK group showed a statistically significant reduction in spherical equivalent and refractive cylinder when compared with the IOL exchange group (P < .001 and P = .001, respectively). The LASIK group showed statistically significant reduced refractive cylinder in comparison with the piggyback lens group (P = .002). The median efficacy index was 0.58 (range: 0.28 to 0.93), 0.75 (range: 0.65 to 0.92), and 0.91 (range: 0.85 to 1.14) in the IOL exchange, piggyback lens, and LASIK groups, respectively. Statistically significant differences were found between the IOL exchange and LASIK groups (P = .004) and the piggyback lens and LASIK groups (P = .003). No statistically significant differences were detected in the safety index among groups (P = .094). The predictability (±1 diopters of final spherical equivalent) was 62.5% of eyes in the IOL exchange group, 85% of eyes in the piggyback lens group, and 100% of eyes in the LASIK group. The three procedures were effective. The LASIK group showed the best outcomes in efficacy and predictability.

Management of Vascularized Limbal Keratitis With Prosthetic Replacement of the Ocular Surface System

To describe a case of contact lens-induced vascularized limbal keratitis (VLK) and management with prosthetic replacement of the ocular surface system (PROSE) treatment. Clinical retrospective case report describing the clinical appearance, course of development, and treatment of VLK with PROSE. A 58-year-old white woman presented with a history of advanced keratoconus and almost four decades of contact lens wear, including polymethyl-methacrylate, small-diameter, gas-permeable lenses, low-Dk hybrid, and piggyback lens modalities. Complications of lens wear caused the development of extensive VLK in both eyes, with vascularization, lipid keratopathy, and corneal scarring projecting into the central cornea, more so in the left eye. She was evaluated and treated with PROSE in both eyes, demonstrating initial improvements in both comfort and vision, from 20/30 to 20/25 in the right eye and from 20/40 to 20/20 in the left eye. After 2 years of PROSE treatment, she reported excellent vision and comfort. Acuities were OD 20/25(+2) and OS 20/20(-/+). There was normalization of the corneal surface with reduced staining and epithelial irregularity, and there was substantial regression of corneal neovascularization and opacity, particularly in the left eye. PROSE, by normalizing the environment at the ocular surface, ultimately improved visual function and long-term ocular health for this patient.

Effects of Contact Lenses on the Ocular Surface in Patients With Keratoconus: Piggyback Versus ClearKone Hybrid Lenses

Because patients with keratoconus tend to wear contact lens for a long period of time, they are more prone to ocular surface changes induced by the lenses. This study aimed to compare immunohistochemical changes induced by two different types of contact lenses in patients with keratoconus. Twenty-four contact lens-naive keratoconus patients (30 eyes) were included in this prospective study. Group 1 comprised 14 eyes (12 patients) wearing piggyback lenses, and group 2 comprised 16 eyes (12 patients) wearing ClearKone hybrid lenses. The patients were analyzed for bulbar conjunctival impression cytology, tear interleukin-6 (IL-6) and IL-8 levels, and confocal microscopic changes of the cornea before and 6 months after wearing contact lenses. Six months after wearing contact lenses, the groups demonstrated similar epithelial metaplasia rates, tear IL-6 and IL-8 levels, and similar confocal microscopy findings (P>0.05 for all intergroup comparisons). Among the parameters tested in this study, only IL-6 and IL-8 levels and posterior keratocyte density on confocal microscopy showed an increase after 6 months when compared with baseline values but at a similar degree in the two groups. This small sample was not able to demonstrate a difference between the two types of lenses with regard to the variables examined, and further larger trials would be required to determine if differences truly exist or not. However, clinicians may still consider patient comfort and vision in selecting the lens type in patients with keratoconus.

Contact Lenses in the Management of Keratoconus

The range of contact lens modalities currently available for the successful optical correction of keratoconus is greatly expanded. We review lens types currently available for the nonsurgical management of keratoconus, including rigid gas-permeable (GP) lenses, intralimbal lenses, corneoscleral lenses, scleral lenses, hybrid lenses, and piggyback lenses. In this review, we discuss the contemporary range of available lens types and the circumstances in which they are best used.

Advantage of higher oxygen transmissibility material Piggyback lens for keratoconus correction

To evaluate the oxygen transmissibility of new material Piggyback lens combined with silicone hydrogel lens and higher Dk RGPCL. To investigate the improving of visual acuity, ocular shape and comfortable, also orthokeratology results and safety of this new system for keratoconus correction. Calculating the oxygen transmission (Dk/t) of the new Piggyback system involves Ohm's Law. Compare the changes of ocular surface curves and astigmatism with or without Si-SCL fitting, RGPCL vision and Piggyback lens vision. Investigate the comfortable improving and ocular complications, and changes of corneal shape after fitted with Piggyback lens by using corneal topography. Selected silicone hydrogel lens was pure vision (B&L PV, 36% water, Dk/t 110) lens, RGPCL material was Menicon Z, Dk/t 95.9 and Boston XO, Dk/t 58.8. It was calculated to 44.4 Dk/t and 34.4 Dk/t with these two combinations. Twenty two moderate and severe keratoconus patients (28 eyes) fitted with the Piggyback lens successfully. Corneal K reading and astigmatism decreased significantly after wore the Si-SCL. Compared with RGPCL vision(4.82 ± 0.11), Piggyback lens vision (4.93 ± 0.08) was significant increased (t = -10.395, P < 0.01) 90% cases improved comfort vs prior RGPCL wear alone. Only few cases appeared slight conjunctival hyperemia and corneal staining. Corneal topography showed corneal flatter, spherical and regular reshaping results after 6 months wore the Piggyback lens. By fitting Piggyback systems using new Si-SCL and higher Dk RGPCL materials may help problematic keratoconic patients improve visual acuity, comfort and safety, increase wearing time and orthokeratology results further.

Facoemulsificação em cães, com e sem implante de lente intra-ocular em piggyback: estudo clínico da inflamação pós-operatória

A uveíte peri e pós-operatória é o maior problema da cirurgia para extração de catarata no cão, sendo considerada o fator mais importante para o sucesso cirúrgico, imediato e tardio. Diversos protocolos pré e pós-operatórios utilizando agentes anti-inflamatórios esteroidais e não-esteroidais têm sido empregados na tentativa de controle da uveíte cirurgicamente induzida. O objetivo do presente estudo foi avaliar a reação inflamatória pós-operatória, clinicamente e por meio da pressão intraocular (PIO), após a cirurgia de facoemulsificação para extração de catarata em cães, com e sem implante de lente intraocular (LIO) em piggyback. Empregaram-se, 25 cães portadores de catarata, subdivididos em dois grupos: G1 (com implante de LIO), G2 (sem implante de LIO). A técnica cirúrgica adotada foi a facoemulsificação bimanual unilateral. Avaliações clínicas e mensurações da PIO foram aferidas antes do procedimento cirúrgico (0) e nos tempos 3, 7, 14, 21, 28 e 60 dias após o ato cirúrgico. Cães do grupo G1 apresentaram sinais clínicos de uveíte visivelmente mais intensos, relativamente aos do G2. Entretanto, a PIO não demonstrou diferença significativa entre os dois grupos analisados, nem entre os olhos operados e os contralaterais. A utilização de duas LIOs humanas em piggyback no cão é exequível, porém suscita mais inflamação e complicações no pós-operatório.