Scleral Lenses Research Articles

Keratoconus Diagnosis and Treatment: Recent Advances and Future Directions.

Keratoconus is a disorder characterized by progressive corneal thinning and steepening that may result in significant visual impairment secondary to high astigmatism, corneal scarring, or even corneal perforation. Early detection and screening of keratoconus are essential for effective management and treatment. Several screening methods, such as corneal topography and tomography, corneal biomechanics, and genetic testing, are being developed to detect keratoconus at an early stage. Once detected, prevention of progression is the mainstay of keratoconus management. Corneal collagen cross-linking is a minimally invasive treatment option that can slow or halt the progression of keratoconus. Additionally, recent studies have investigated the potential use of copper sulfate eye drops (IVMED-80) and extracellular vesicles to prevent the progression of keratoconus as non-invasive treatment options. For visual rehabilitation, currently available treatments include scleral lenses, intracorneal ring segments, corneal allogenic intrastromal ring segments, and deep anterior lamellar keratoplasty. The safety and efficacy of these emerging treatment options for keratoconus are currently being investigated.

Ocular Surface Homeostasis After Scleral Lens Usage.

The aim of this prospective study is to examine the effects of 5 hours of well-fitted, mini-scleral contact lens (mini-SL) wear on the tear film cytokine expression in healthy eyes. Twenty-three healthy participants were included in the study. One eye of each participant was selected at random, and a mini-SL measuring 16.5 mm in diameter was fitted by an experienced contact lens specialist. The contact lens remained in place for 5 hours. Precorneal tear fluid was collected using capillary tubes at three different time points: baseline before SL insertion (T0), after 5 hours of SL wear (T1), and 3 hours after SL removal (T2). The concentration of 40 inflammatory cytokines at the three different time points was determined using multiplex bead assay. Mini-scleral lens wear did not result in significant changes in the cytokine-to-protein ratio after 5 hours of wear on a healthy eye. Although a well-fitted mini-SL reduces the rate at which the precorneal tear film is refreshed, 5 hours of lens wear did not appear to significantly affect the tears cytokine-to-protein ratio, suggesting that scleral lenses have minimal impact on corneal cytokine expression.

Scleral sutured toric intraocular lens with pars plana vitrectomy for the correction of corneal astigmatism without capsular support.

To describe the repair of a patient with bilateral subluxed cataract and corneal astigmatism in the setting of a coloboma of the iris, zonules, lens, and retina. Pre-operatively his best corrected acuity was 20/500 OD and 20/200 OS. His pre-operative refraction was -7.25 +1.00 at 080 OD and -7.75 +3.00 at 040 OS. On corneal topography, he had 1.95D and 1.45D of regular astigmatism in the right and left eye respectively. This technique involves pars plana vitrectomy in combination with the placement of a MX60 toric intraocular lens fixated to the sclera using 8-0 Gore-Tex in line with the axis of steep corneal astigmatism. The lens is affixed through two pair of nasal and temporal sclerotomies, with each pair located 3 mm posterior to the limbus and 5 mm apart, centered along the axis of steep astigmatism. Post-operatively the patient was 20/25 uncorrected OD and 20/20 uncorrected OS with a refraction of -0.75 +0.50 at 180 in the OD and -0.75 +1.00 at 180 in the OS. Scleral sutured toric intraocular lens placement and pars plana vitrectomy is a viable solution for patients with regular corneal astigmatism and cataract repair in the absence of zonular support.

Central and peripheral scleral lens-induced corneal oedema.

To quantify the magnitude of central and peripheral scleral lens-induced corneal oedema for a range of fluid reservoir thicknesses, and to compare these experimental results with theoretical models of corneal oedema both with and without limbal metabolic support (i.e., the lateral transport of metabolites and the influence of the limbal vasculature). Ten young healthy participants wore scleral lenses (KATT™, Capricornia Contact Lenses) fitted with low (mean 141 μm), medium (482 μm) and high (718 μm) central fluid reservoir thickness values across three separate study visits. The scleral lens thickness, fluid reservoir thickness and stromal corneal oedema were measured using optical coherence tomography. Oedema was quantified across the central (0-2.5 mm from the corneal apex) and peripheral (1.25-3 mm from the scleral spur) cornea. Experimental data were compared with published theoretical models of central to peripheral corneal oedema. Stromal oedema varied with fluid reservoir thickness (p < 0.001) for both central and peripheral regions. The mean (standard deviation) stromal oedema was greater for the medium (2.08 (1.21)%) and high (2.22 (1.31)%) fluid reservoir thickness conditions compared to the low condition (1.00 (1.01)%) (p ≤ 0.01). Stromal oedema gradually increased from the corneal centre to the periphery by ~0.3% on average (relative increase of 18%), but the change did not reach statistical significance. This trend of increasing, rather than decreasing, oedema towards the limbus is consistent with theoretical modelling of peripheral oedema without metabolic support from the limbus. The central and peripheral cornea displayed a similar magnitude of oedema, with increasing levels observed for medium and high fluid reservoir thicknesses. The gradual increase in oedema towards the limbus is consistent with a 'without limbal metabolic support' theoretical model.

Quintuple Procedure for Ocular Surface Reconstruction and Visual Rehabilitation.

The aim of this study was to describe a combined surgical approach for ocular surface and visual rehabilitation in patients with limbal stem cell deficiency, corneal scarring, and cataract. We aimed to introduce this combined approach as an alternative to a staged approach and to describe the intraoperative use of a diamond ophthalmic burr (DOB) and optical coherence tomography (OCT) to achieve and confirm a smooth graft-host interface during the anterior lamellar keratoplasty (ALK) portion of the procedure. The quintuple procedure described herein consists of a modified ALK, cataract extraction, intraocular lens implantation, simple limbal epithelial transplantation, and temporal tarsorrhaphy. Intraoperative OCT and DOB were used to guide the creation of the stromal bed during the ALK. The procedure was performed in a patient with limbal stem cell deficiency and corneal scarring after a chemical ocular burn. The tarsorrhaphy was removed at 3 months postoperatively once complete corneal epithelialization was observed. The best-corrected visual acuity improved from light perception preoperatively to 20/30 at 16 months postoperatively with the use of scleral contact lenses. At this postoperative time point, the cornea was clear and compact, and the ocular surface was stable. The quintuple procedure allowed for visual and ocular surface rehabilitation in cases in which follow-up for a staged approach was not possible. Intraoperative OCT allowed for real-time visualization and dissection of the stromal bed, whereas the use of the DOB helped achieve a smooth stromal surface for an optimal graft-host interface.

High Astigmatism Secondary to Peripheral Ectasia Recurrence in Postpenetrating Keratoplasty Eyes Managed With Miniscleral Contact Lenses.

After penetrating keratoplasty (PK) for keratoconus, vision can be impaired by high-degree astigmatism, particularly in those patients with recurrent peripheral ectasia. Scleral contact lenses (CLs) have long been used in the management of keratoconus both in treatment-naive corneas and those postcorneal transplants. We report the use of miniscleral CLs and their related visual and clinical outcomes in a series of patients with post-PK peripheral rim ectasia. In this retrospective case series, 5 patients (7 eyes) presented because of reduced visual acuity with their spectacles/CLs and/or reduced comfort with their existing rigid gas-permeable lenses. All patients in this series underwent PK more than two decades ago for keratoconus (mean 28.7 years±7.2). All patients demonstrated characteristic thinning at the graft-host junction, with anterior chamber deepening. Central corneas had remained clear in all patients inferring high visual potential. Contact lenses used were No 7 Comfort 15 miniscleral and the Onefit MED scleral with 14.5 mm and 15.6 mm diameters, respectively. All eyes achieved a best-corrected visual acuity of 6/9 or greater. One case had difficulty with insertion and removal and has since discontinued wearing lens at this time. All others are successfully wearing the lenses regularly. Despite advances in CL design, surgical management is still required in some patients. Miniscleral CLs are effective in the refractive management of peripheral ectasia in keratoconic post-PK eyes and should be considered in such eyes before proceeding with repeat surgical intervention.

Average Scleral Lens Replacement Period at a Tertiary Care Hospital.

To evaluate the average scleral lens replacement period at a tertiary care hospital. Patients were identified retrospectively through electronic medical records. Inclusion criteria included scleral lens patients treated at the USC Department of Ophthalmology who had reordered a scleral lens at least once in one eye. Lens order histories were evaluated, and statistical analysis included a multivariable, mixed-methods, linear, regression model. Two hundred fifty-one patients (120 men and 131 women; average age 57.1±17.4 years, range 9-93 years) and a total of 445 eyes (227 OD, 218 OS; 199 irregular corneas, 246 ocular surface disease) were included. The average replacement period for a scleral lens was 23.9±14.3 months (range 5-2,617 days). Patients with greater scleral lens experience had a statistically significant increase in their average scleral lens replacement period; for every one year of additional experience wearing scleral lenses, average replacement period increased by 30.7 days ( P =0.001). There was no statistically significant correlation between average scleral lens replacement period and sex, diagnosis, prior outside scleral lens treatment, lens brand, or lens diameter. The average scleral lens replacement period in this patient cohort at a tertiary care hospital was 23.9±14.3 months (1.99±1.19 years). Further studies are needed to better understand the impact of scleral lens age on ocular health and vision. Certainly, proper scleral lens training and education are essential to ensure optimal lens condition and treatment outcomes.

Assessment by Optical Coherence Tomography of Short-Term Changes in IOP-Related Structures Caused by Wearing Scleral Lenses.

The mechanism that could increase intraocular pressure (IOP) during scleral lens (SL) wear is not fully understood, although it may be related to compression of the landing zone on structures involved in aqueous humor drainage. Thirty healthy subjects were fitted with two SLs of different sizes (L1 = 15.8 mm, L2 = 16.8 mm) for 2 h in the right eye and left eye as a control. Central corneal thickness (CCT), parameters of iridocorneal angle (ICA), Schlemm's canal (SC), and optic nerve head were measured before and after wearing both SLs. IOP was measured with a Perkins applanation tonometer before and after lens removal and with a transpalpebral tonometer before, during (0 h, 1 h, and 2 h), and after lens wear. CCT increased after wearing L1 (8.10 ± 4.21 µm; p < 0.01) and L2 (9.17 ± 4.41 µm; p < 0.01). After L1 removal, the ICA parameters decreased significantly (p < 0.05). With L2 removal, nasal and temporal SC area and length were reduced (p < 0.05). An increased IOP with transpalpebral tonometry was observed at 2 h of wearing L1 (2.55 ± 2.04 mmHg; p < 0.01) and L2 (2.53 ± 2.22 mmHg; p < 0.01), as well as an increased IOP with Perkins applanation tonometry after wearing L1 (0.43 ± 1.07 mmHg; p = 0.02). In the short term, SL resulted in a slight increase in IOP in addition to small changes in ICA and SC parameters, although it did not seem to be clinically relevant in healthy subjects.

A clinical case of fitting scleral contact lenses for congenital bilateral eyelid coloboma complicated by exposure keratopathy

A clinical case of fitting scleral contact lenses for congenital bilateral eyelid coloboma complicated by exposure keratopathy

Commentary - Scleral lenses: The leading edge.

Commentary - Scleral lenses: The leading edge.

Bleeding fluorescein in the fluid reservoir of scleral lens

Bleeding fluorescein in the fluid reservoir of scleral lens

A new method for determining the shape of the sclera

Purpose. The aim of the present theoretical modelling study is to improve the fitting of scleral lenses by means of a novel determination of the scleral shape of the eye. Material and Methods. . The movement of scleral lenses and soft lenses is affected by scleral shape around the limbus. Based on this, it is important to take a closer look at the edge of the sclera. An area of 4 mm in diameter around the limbus is considered as a suitable area for shape fitting, which is shown by 44 profile photographs. As a first step, a straight line (y = m • x + b) was fitted on scleral data of 44 perpendic- ular cuts. Then, these measuring points were rotated around the first “scleral measuring point after the limbus” (angle of rotation = − arctan (m)) so that all measuring points were horizontal. A parabola was then fitted as best as possible (y = a • x2 + b • x + c) to the rotated measuring points. The parabola coefficient a or “pca value” plays a central role as a shape criterion of the corneo-scleral profile (CSP). A pca value a ≥ 0.1 means the CSP is a concave parabola, while a ≤ −0.1 implies that the CSP is a convex one. If the pca value is between −0.1 &lt; a &lt; 0.1, the CSP is a straight line. Results. Based on the 44 profile section photos, 85.8 % of the CSPs were straight, 11.1 % were convex and 3.1 % were concave parabolic shapes. The probability of determining a parabolic CSP section is about 18.5 % (normal distribution, the normal distribution test for the calculated pca values shows p &lt; 0.01). Conclusion. A specification of the corneo-scleral-profile (CSP) with the corresponding scleral angle “alpha”, gives significantly more information about the scleral shape than if only one of the two parameters is specified. Furthermore, this simplifies the determination of the geometry of contact lenses with large diameters, especially scleral lenses. Keywords Soft contact lenses, scleral lenses, corneo-scleral profile, scleral shape, sclera

Case Series: Transient Corneal Subepithelial Macrocysts with Scleral Contact Lens Wear

Scleral lens wear is indicated in cases of corneal irregularity and ocular surface disease to improve vision and ocular surface condition. The purpose of this case series is to discuss transitory corneal subepithelial macrocysts associated with scleral lens wear in various conditions such as dry eye, post-radial keratotomy, and post-superficial keratectomy. Such diseased or damaged corneas have weakened epithelial attachments which can lead to macrocyst formation. Three cases documented with spectral-domain anterior segment optical coherence tomography highlight the clinical presentation of corneal subepithelial macrocysts. CE Notification: This article is available as a COPE accredited CE course. You may take this course for 1-hour credit. Read the article and take the qualifying test to earn your credit. Please check COPE course expiry date prior to enrollment. The COPE course test must be taken before the course expiry date.

Оптические методы коррекции посткератопластической аметропии

Purpose. The analysis of the advantages and disadvantages of existing optical methods for correcting postkeratoplastic ametropia (PA). Material and methods. When studying the literature review on PA correction, a search was carried out for sources in the PubMed and Scopus abstract databases for the period up to 2021 inclusive. In total, 50 articles related to the topic of the review were selected, including long-term observations on the methods of optical correction of PA that are currently used worldwide. Results. Today, in addition to spectacle and contact correction, there is a large selection of various methods of surgical correction of PA: wedge resection, various options for keratotomy, implantation of toric intraocular lenses, phakic toric lenses, refractive laser surgery – photorefractive keratectomy, laser in situkeratomileusis, ReLEx SMILE technology, and also implantation of intrastromal corneal segments. The choice of the most optimal optical method for PA correction, depending on the initial individual clinical and functional parameters of the patient, remains quite relevant today. This is due both to a large number of different methods of PA correction, each of which has its own advantages and disadvantages, which necessitates their improvement, and to the need to develop new techniques. Conclusion. Currently, there are a large number of various methods for correcting postkeratoplastic ametropia, each of which has its own advantages and disadvantages. It is necessary to develop a systematic approach to the personalized choice of an optical method for correcting postkeratoplastic ametropia, taking into account its effectiveness and safety, depending on the individual clinical and functional data of the patient. There is a need for the development of new methods of correction that would effectively and safely correct high values of postkeratoplastic ametropia, especially with an asymmetric type of keratotopogram. Key words: postkeratoplastic ametropia, femtosecond laser, corneal segments, scleral contact lenses

Keratoconic patient profile and management at public sector facilities in South Africa

Background: Keratoconus (KC) is a condition marked by thinning and protrusion of the cornea resulting in high myopia and irregular astigmatism. Knowledge of KC patients’ profiles and management approaches used can help to predict the needs of public hospitals to improve patient care.Aim: This study aimed to describe the profiles and management of KC patients.Setting: Capricorn district, Limpopo Province, South Africa.Methods: Medical records of 188 KC patients attending public hospitals of Capricorn District from January 2017 to December 2020 were reviewed. Data on patient profile and their management were collected and analysed.Results: The mean age of KC patients was 20.64 ± 6.82 years and the majority (56.9%) were males. Clinical findings were mean unaided visual acuity (UVA) of 0.19 ± 0.18, best corrected VA of 0.53 ± 0.24, spherical equivalence of -4.89 ± 9.17 dioptre (D), mean K of 57.37 ± 17 D and corneal astigmatism of -6.24 ± 4.27 D. A total of 54.5% of patients had severe KC. Bilateral KC was found in almost all patients (97.3%) and a mean K difference of 7.59 ± 6.08 D (p 0.001) between the better and the worse eye. The study found no significant difference in KC severity by age (p = 0.451) and gender (p = 0.819). Patients fitted with scleral lenses had the highest VA improvement of 0.44 ± 0.17.Conclusion: Most patients presented with bilateral and severe KC. Scleral lenses provided higher VA improvement than other methods.Contribution: The study aimed to present the clinical profile and management of keratoconic patients attending public sector facilities. Knowledge of the patterns of KC presentation may assist in the development of intervention strategies and guidelines for best practice in the management of KC, especially in public sector facilities.

Impact of Scleral Lens Front Surface Eccentricity on Visual Acuity, Contrast Sensitivity, and Higher-Order Aberrations in Eyes With Keratoconus.

To investigate the effect of front surface eccentricity (FSE) of scleral lenses (SLs) on corrected distance visual acuity (CDVA), contrast sensitivity (CS), and higher-order aberrations (HOAs) in keratoconic eyes. Fifteen keratoconic eyes fitted with BostonSight SCLERAL lenses of different eccentricity values (FSE0=0, FSE1=0.30, and FSE2=0.60). CDVA, CS, and HOAs were measured at baseline and after 30 min of SL wear. CDVA and CS were measured with the Early Treatment Diabetic Retinopathy Study and Pelli-Robson chart, respectively, and iTrace aberrometer was used to evaluate the HOAs. Baseline CDVA was 0.30±0.29, which significantly improved to 0.10±0.11, 0.05±0.06, and 0.05±0.08 logMAR with FSE0, FSE1, and FSE2, respectively ( P <0.05). The post hoc showed no significant difference between eccentricities. Baseline CS was 1.19±0.47, which improved to 1.54±0.12, 1.59±0.10, and 1.60±0.11 with FSE0, FSE1, and FSE2, respectively ( P <0.01), but post hoc showed no significant difference between eccentricities. A statistically significant reduction was found in HOAs when compared with baseline ( P <0.01). Comparison between eccentricities showed a significant difference only between FSE0 and FSE1 for RMS coma ( P =0.01) and RMS spherical aberrations ( P =0.004) where FSE1 showed better performance in reducing HOAs compared with FSE0. HO-RMS, RMS secondary astigmatism, and RMS trefoil showed no significant difference between eccentricities, but FSE1 and FSE2 performed superior to FSE0. BostonSight SCLERAL lenses with varying eccentricities corrected a significant amount of HOAs and improved CDVA and CS in keratoconus patients. Practitioners should be aware of this distinct feature of SLs and use it as needed to improve visual performance.

Comparison of Surgical Outcomes between Conventional Sutured Scleral Fixation and Flanged Intrascleral Intraocular Lens Fixation

Purpose: We compared the surgical outcomes and complications of conventional, sutured scleral fixation and flanged intrascleral intraocular lens (IOL) fixation.Methods: We retrospectively analyzed the medical records of patients who underwent conventional, sutured scleral fixation or flanged intrascleral IOL fixation and who were then observed for more than 6 months. The best-corrected visual acuity (BCVA), operation time, spherical equivalent (SEQ), astigmatism, and postoperative complications were recorded up to 6 months after surgery.Results: Of sixty-nine enrolled eyes, 39 underwent conventional, sutured scleral fixation (“sutured” group) and 30 flanged intrascleral IOL fixation (“sutureless” group). The operation time was significantly shorter in the sutureless group than in the sutured group (56.3 ± 11.8 vs. 77.7 ± 17.9 minutes, &lt;i&gt;p&lt;/i&gt; &lt; 0.001). In both groups, the BCVA and SEQ improved significantly at all visits after surgery compared to the baseline values &lt;i&gt;p&lt;/i&gt; &lt; 0.05). There was no between-group difference in BCVA, SEQ, astigmatism, or complications.Conclusions: Compared to conventional, sutured scleral fixation, flanged intrascleral IOL fixation afforded equivalent improvements in visual acuity but with a shorter surgical duration. Therefore, flanged intrascleral IOL fixation is a useful alternative to conventional, sutured scleral fixation.

Corneal oedema during reverse piggyback scleral lens wear.

One clinical approach to address poor front surface wettability during scleral lens wear is the use of a "reverse piggyback" system (a soft contact lens applied to the anterior surface of a scleral lens). The aim of this study was to compare the magnitude of corneal oedema induced following short-term reverse piggyback scleral lens wear and standard scleral lens wear. Ten young (mean age 22 ± 6 years) healthy participants with normal corneas were recruited. On separate days, central corneal thickness and fluid reservoir thickness were measured using optical coherence tomography before and after 90 min of standard scleral lens wear (Kerectasia Alignment Tangent Torus diagnostic lenses, hexafocon A, Dk 100 × 10-11 (cm2 /s)(ml O2 /ml × mmHg), Capricornia Contact Lenses, capcl.com.au) and reverse piggyback scleral lens wear (the same scleral lens with a Dailies Total 1®, delefilcon A, Dk 140 × 10-11 (cm2 /s)(ml O2 /ml × mmHg), Alcon, alcon.com, applied to the anterior scleral lens surface). After correcting for small variations in the initial central fluid reservoir thickness, central corneal oedema was similar between the reverse piggyback (2.32 ± 1.15%) and standard scleral lens conditions (2.02 ± 0.76%; p = 0.45). Following 90 min of lens wear, the highly oxygen-permeable reverse piggyback system did not induce a clinically or statistically greater magnitude of central corneal oedema compared with standard scleral lens wear in young adults with healthy corneas. This approach may be suitable to address poor front surface scleral lens wettability or to correct residual refractive error during diagnostic scleral lens fitting.

Contact lens embedded holographic pointer

In this paper we present an infrared laser pointer, consisting of a vertical-cavity surface-emitting laser (VCSEL) and a diffractive optical element (DOE), encapsulated into a scleral contact lens (SCL). The VCSEL is powered remotely by inductive coupling from a primary antenna embedded into an eyewear frame. The DOE is used either to collimate the laser beam or to project a pattern image at a chosen distance in front of the eye. We detail the different SCL constitutive blocks, how they are manufactured and assembled. We particularly emphasize the various technological challenges related to their encapsulation in the reduced volume of the SCL, while keeping the pupil free. Finally, we describe how the laser pointer operates, what are its performances (e.g. collimation, image formation) and how it can be used efficiently in various application fields such as visual assistance and augmented reality.

Scleral lens fluid reservoir turbidity with solutions of varying viscosities

Scleral lens fluid reservoir turbidity with solutions of varying viscosities