Effects of scleral-lens oxygen transmissibility on corneal thickness: A pilot study

PurposeTo investigate the effect of various oxygen transmissibilities (Dk/t) of scleral lenses and corneal thickness recovery time from overnight eye closure with patching on corneal edema during 5 h lens wear.MethodsScleral lenses (hofocon A, 15.6 mm diameter) were worn bilaterally with three different Dks (100, 140, and 160 Barrer). Central and peripheral corneal thickness (CCT and PCT) were measured using optical coherence tomography. Four subjects were randomly selected for one additional visit and asked to patch one eye before night sleeping. The patch was not removed until lens insertion to avoid corneal deswelling. Then CCT of both eyes was measured.ResultsTen neophytes with healthy eyes participated in the study. Mean [95% CI] Dk/t of the study lenses was 32.0 [29.2, 34.7] hBarrer/cm. Mean [95% CI] CCT immediately upon lens insertion and after 5 h of lens wear were 532.4 [520.3, 544.5] μm and 538.7 [526.5, 551.0] μm, respectively. Mean [95% CI] percentage change (%Δ) in CCT was 1.2% [0.9%, 1.5%], 1.2% [0.9%, 1.4%], and 0.8% [0.6%, 1.1%] for CCT, nasal PCT, and temporal PCT, respectively. There was an inverse relationship between temporal Dk/t and %ΔPCT (p < 0.05) while Dk/t was not found significantly associated with either CCT or nasal PCT. The patched eyes maintained a relatively stable CCT and showed progressive deswelling, starting and ending with 2.8% and 0.6%, respectively. In contrast, the unpatched eyes swelled, starting with nearly 0% and ending with 0.7% with a maximum swelling of 1.8%.ConclusionThere was limited amount of corneal edema induced by short-term scleral lens wear with lens Dk/t ranging from 21 to 47 hBarrer/cm and lenses with lower lens Dk/t did not induce significantly higher corneal swelling. Scleral lens insertion soon after overnight eye closure with patching did not introduce additional swelling for young and healthy eyes.     

Fluid reservoir thickness and corneal oedema during closed eye scleral lens wear

PurposeTo examine the relationship between central post-lens fluid reservoir thickness and central corneal oedema during short-term closed eye scleral lens wear, and to compare these empirical oedema measurements with open eye lens wear data and current theoretical modelling for overnight scleral lens wear.MethodsTen participants (mean ± standard error 30 ± 1 years) with normal corneas wore scleral lenses (Dk 141 × 10⁻¹¹ cm³ O₂(cm)/[(sec.)(cm²)(mmHg)) under closed eye conditions on separate days with an initial central post-lens fluid reservoir thickness considered to be low (160 ± 7 μm), medium (494 ± 17 μm), or high (716 ± 16 μm). Epithelial, stromal, and total corneal oedema were measured using high-resolution optical coherence tomography immediately after lens application and following 90 min of wear, prior to lens removal. Data were compared to open eye scleral lens induced corneal oedema and a theoretical model of overnight closed eye scleral lens wear (Kim et al., 2018).ResultsCentral corneal oedema was primarily stromal in nature and increased with increasing fluid reservoir thickness; the mean total corneal oedema was 3.86 ± 0.50%, 4.71 ± 0.28% and 5.04 ± 0.42% for the low, medium, and high thickness conditions, respectively. A significant difference in stromal and total corneal oedema was observed between the low and high fluid reservoir thickness conditions only (both p ≤ 0.01). Theoretical modelling overestimated the magnitude of central corneal oedema and the influence of fluid reservoir thickness upon corneal oedema during closed eye conditions.ConclusionScleral lens induced central corneal oedema during closed eye lens wear increases with increasing fluid reservoir thickness, but at a decreased rate compared to theoretical modelling.     

Optical considerations for scleral contact lenses: A review

Scleral contact lenses have a range of therapeutic and optical applications. In recent years, scleral lens prescribing has increased due to significant advances in ocular imaging technology, lens manufacturing processes, and the widespread availability of scleral lenses globally. While the optical principles of scleral lenses are identical to those of corneal rigid lenses (i.e. the post-lens tear layer neutralises the majority of anterior corneal astigmatism and higher order aberrations), the nature of scleral lenses and their typical fitting characteristics means that many of the assumptions of ‘thin lens’ paraxial optics traditionally used for corneal rigid lens calculations may be inappropriate in certain clinical scenarios. This review provides a comprehensive overview of a variety of lens and fitting characteristics that are unique to scleral lenses, or not typically encountered with corneal rigid lenses, and how these factors may potentially influence optical performance based on theoretical modelling, in particular; scleral lens parameters, the post-lens tear layer, and dynamic changes during lens wear. Current front and back surface lens designs and future scleral lens applications are also discussed, along with lens modifications to improve visual outcomes and transient changes in corneal optics induced by appropriately fitted modern scleral lenses.     

Performance and predictability of a new large diameter contact lens design in keratoconic corneae

ObjectivesTo evaluate the clinical performance and predictability using corneal topography in the fitting of a new large-diameter rigid gas permeable (RGP) contact lens design in eyes with keratoconus (KCN).MethodsThis study presents a review of eyes fitted with Alexa ES lenses for nonsurgical optimisation of visual correction. Anterior steep simulated keratometry (sim-K steep), corneal diameter (HVID), the Curvature at the apex in diopters (Cc), and distance from the corneal apex to the centre of the cornea (Lc) in millimetres derived from the Cone Location and Magnitude Index (CLMI) were recorded. Visual acuity, mean wearing time, final sagittal depth and adverse events were also recorded. Correlations between topographic indices and base curve were evaluated using the Pearson correlation coefficient.ResultsForty-six eyes from 26 patients (19 males/ 7 females) were included. Mean visual acuity improved from 0.49 ± 0.32 with glasses, to -0.02 ± 0.10 with the contact lens. The mean daily wear time was 12.19 ± 1.96 hours. No complications were detected in 95.65% of the eyes [95% CI (83.9%-99.2%)] but two episodes of non-infectious keratitis. The average sagittal depth of the lenses fitted was 0.425 ± 0.15 mm, and it was positively correlated with the Cc value (r² = 0.66, p< 0.0001, n=46) derived from the CLMI index of the pre-fitting topography.ConclusionsCorneoscleral RGP contact lenses are a safe, and effective alternative for managing KCN patients to corneal lenses. Also, clinical data derived from the corneal topography could be used to help to decide the first diagnostic lens to be assessed, easing the overall fitting process.     

The treatment of ocular hypotony after trabeculectomy with a scleral lens: A case series

PurposeOcular hypotony after trabeculectomy may be treated medically, surgically and with a tamponade. Three cases are reported in which a scleral lens was applied to treat ocular hypotony after mitomycin C (MMC) augmented trabeculectomy.MethodsIn this retrospective case series the records of three eyes of three patients who developed ocular hypotony after they had undergone trabeculectomy augmented with MMC were evaluated. The patients were between 11 and 69 years of age and the intraocular pressure (IOP) after surgery ranged between 3 and 6 mmHg. All three patients showed a negative Seidel test; one had suspected hypotonic maculopathy and one had a collapsed anterior chamber. After unsuccessful treatment with large bandage lenses all three patients were subsequently fitted with a scleral lens. The scleral lens was fitted to fully cover and compress the bleb. Scleral lenses were worn continuously with a check-up after one night of wear and subsequent check-ups when needed. One patient continued to wear the scleral lens for a further 6.5 months on a daily wear basis.ResultsIn all three eyes the IOP was higher after wearing the scleral lens. Two patients stopped wearing the scleral lens after the IOP was stable. One patient developed a cataract; the cataract surgery was combined with a bleb revision and scleral lens wear was therefore discontinued.DiscussionThe scleral lens might be a useful tool in the treatment of ocular hypotony after trabeculectomy augmented MMC surgery. The effect of the scleral lens on the ocular pressure is unpredictable. Caution is advised in vulnerable corneas due to risk factors such as hypoxia and infection. Further research is warranted to establish the safety of the procedure, the patient selection and the overall success in a larger patient group.     

The time course and nature of corneal oedema during sealed miniscleral contact lens wear

PurposeTo examine the magnitude and time course of central epithelial, stromal and total corneal thickness changes during sealed miniscleral contact lens wear and the influence of initial central corneal clearance upon these thickness changes.MethodsHigh-resolution OCT images were captured over an 8 h period of miniscleral contact lens wear (using a rotationally symmetric 16.5 mm diameter lens) in 15 young, healthy participants with normal corneae. Corneal thickness data were derived from OCT images using semi-automated image processing techniques over the central 4 mm.ResultsChanges in stromal and total corneal thickness followed a similar pattern throughout lens wear with oedema first detected 15 min after lens insertion (0.47 ± 0.09% increase in stromal and total corneal thickness, both p < 0.01) which peaked after 90 min of lens wear (1.36 ± 0.24% increase in stromal and 1.18 ± 0.20% increase in total corneal thickness, both p < 0.01) and gradually decreased thereafter. Epithelial thickness increased slightly during the first 30 min of lens wear (0.56 ± 0.30% increase, p > 0.05), then rapidly decreased reaching a minimum thickness 480 min after lens insertion (2.38 ± 0.70% decrease, p < 0.05). The maximum total corneal oedema, maximum stromal oedema, and maximum epithelial thinning were not associated with the initial central corneal clearance or the extent of lens settling over the 8 h period (all p > 0.05). Greater initial central corneal clearance resulted in less oxygen concentration reaching the cornea (∼2% less) based on previously published data, which manifested as ∼0.5% more central corneal oedema.ConclusionsScleral lens induced corneal oedema is stromal in nature. On average, central stromal and total corneal thickness increased rapidly following lens insertion and peaked after 90 min, while central epithelial thickness gradually decreased throughout lens wear consistent with natural diurnal variation. A greater initial central corneal clearance resulted in reduced oxygen delivery to the cornea, which had minimal short-term impact upon healthy eyes, however, minimising central corneal clearance may be important in eyes with reduced endothelial cell function to minimise hypoxic stress.     

Corneal epithelial thickness and corneal curvature changes during the day: The effects of daily disposable contact lens wear

PurposeTo evaluate the changes in corneal epithelial thickness and corneal anterior and posterior curvatures during the day, and the effect of wearing daily disposable soft contact lenses.MethodsThirty-two healthy volunteers were enrolled in a randomized crossover study. At the baseline visit, corneal and epithelial thickness maps (OCT; Optovue, Inc., Fremont, CA, USA) and keratometric measurements (Pentacam, Oculus, GmbH, Germany) were performed in the morning and in the afternoon (8 hours after). Then, each subject was fitted with the following brands of daily disposable contact lenses in random order: Dailies Total 1 (Delefilcon A), Dailies Aqua Comfort (Nelfilcon A), TruEye (Narafilcon A) and Biotrue Oneday (Nesofilcon A) on different days. All fitted lenses had a power of −3.00 diopters (D). Measurements were repeated before putting the contact lens on and after an-eight-hour contact lens wear.ResultsWith no lens wear, the anterior topographic indices showed significant steepening [Kflat: p < 0.0001; Ksteep: p < 0.0001 and maximum keratometry value (Kmax): p = 0.04] and the corneal thickness significantly decreased in the central and temporal portion of the cornea in the afternoon. There were no significant changes in the posterior topographical indices and corneal epithelial thickness. With contact lens wear, no significant change occurred in the corneal and epithelial thickness, and the anterior and posterior curvatures during the day (all p values >0.05). There was no statistically significant difference in the epithelial thickness among the groups wearing different contact lens types (p > 0.05).ConclusionsAnterior corneal topographic indices steepen depending on the natural diurnal variations. Daily wear of soft contact lenses appears to mask this steepening. The corneal epithelial thickness is not affected by daily disposable soft contact lenses.     

Redistribution of the corneal epithelium after overnight wear of orthokeratology contact lenses for myopia reduction

BackgroundTo investigate changes in the corneal thickness profile in juvenile myopia after overnight wear of orthokeratology lenses (OK).MethodsA total of 53 juveniles (53 right eyes) successfully wore OK between January 2016 and July 2017 and they were reviewed one day, one week and one month after first wearing it. Epithelial and corneal data were obtained by optical coherence tomography (OCT). Changes in uncorrected visual acuity, refractive error, corneal refractive power, and epithelial and corneal thickness were analyzed before and after wear of OK.ResultsThe corneal epithelium was reshaped after 1 day of OK; the myopia degree was reduced, and uncorrected visual acuity reached 0 logMAR at 1 week. The central (2 mm) average epithelial thickness was 52.04 ± 2.35 μm, 49.25 ± 2.67 μm, 45.91 ± 2.80 μm, and 47.53 ± 3.44 μm before and after 1 day, 1 week, and 1 month of OK, respectively (t = 4.497, 9.741, and 7.340, respectively, P<0.001). The central epithelium was thinnest at 1 week, when the average thinning of 6.13 ± 1.67 μm accounted for approximately 11.78 % ± 3.21 % of the total epithelium thickness at baseline. The epithelial thickness of the reverse curve zone was 51.83 ± 2.49 μm, 57.62 ± 3.01 μm, 59.43 ± 3.19 μm, and 60.22 ± 2.75 μm before and after 1 day, 1 week, and 1 month of OK, respectively, showing a significant increase over time (t=-4.752, -6.208, and -6.848, respectively, P < 0.001).ConclusionIn the early stage of OK, the corneal epithelium was redistributed very quickly. The central epithelium became thin, while the epithelium of the reverse curve zone correspondingly thickened. Effectively reduced the refractive power of the cornea equivalent to the effect of adding a concave spectacle lens, which ensures uncorrected vision after removal of the lenses.     

Soft contact lens-induced corneal deformation in the posterior corneal surface

ObjectiveThis case report aims to highlight the corneal deformation induced by soft contact lens (SCL) wear, which is accompanied by changes in not only the anterior but also the posterior surface of cornea.Case ReportCases are presented of two patients who wore non- planned replacement SCL for more than 15 years fabricated from materials with low oxygen permeability, sought a consultation with complaints of visual acuity loss in the both eyes. Anterior segment optical coherence tomography imaging demonstrated corneal deformation in the posterior as well as the anterior surface in both eyes of two patients, resulting in the diagnosis of corneal deformation induced by SCL wear. After the cessation of lens wear, there were improvements in visual acuity, anterior and posterior corneal higher-order aberrations, and changes in the anterior corneal shape, whereas the posterior corneal shape was improved in one case and remained mildly deformed in the other case.ConclusionWearing SCLs with low oxygen permeability for long time periods, could induce corneal deformation in patients, indicating the need for careful observation of changes in not only the anterior but also the posterior corneal surface.     

Corneal epithelial bullae after short-term wear of small diameter scleral lenses

Complications of scleral lens wear are not well documented or understood. While multiple studies focus on oxygen transmission during scleral lens wear and associated corneal swelling, little is known about the effects of varying scleral lens fitting relationships, especially when there is corneal interaction. Scleral lenses, by convention, are designed to completely clear the corneal surface and rest on the conjunctival and scleral tissue. However, some designs maximize oxygen transmission by reducing the lens diameter, thickness, and recommended corneal clearance.While the modifications increase oxygen transmission in any scleral lens design, they also distribute the lens mass closer to the limbus and make visualization of corneal clearance, especially narrow in the limbal region, more difficult. The sequelae from mechanical interaction between scleral lenses and the ocular surface, in particular the cornea, remain uncertain.This case series will describe corneal epithelial bullae, molding, and epithelial erosions as unintended scleral lens complications. These corneal changes corresponded to areas of contact lens-corneal bearing confirmed utilizing a combined scanning laser ophthalmoscopy (SLO) and anterior segment OCT. This case series will discuss epithelial bullae detection, their etiology, and suggestions for application of this information into scleral lens fitting protocols.     

Scleral contact lenses for visual rehabilitation after penetrating keratoplasty: Long term outcomes

PurposeTo evaluate the success rate of highly gas permeable scleral contact lenses (SCL) for visual rehabilitation after penetrating keratoplasty (PK), over a period of up to 9 years.MethodsA total database of 31 consecutive patient fitted with SCL between January 2004 and December 2009 was retrospectively reviewed. Demographic data, etiology prior to lens fitting, visual outcomes, follow up time and complications were analyzed.ResultsAll eyes were fitted due to inadequate spectacle-corrected vision after successful penetrating keratoplasty or failure of other contact lens modalities. Out of 31 patients fitted, 28 (33 eyes) continue to wear SCL for periods between 0.5 and 8.8 years. The mean duration of follow-up after contact lens fitting was 5.2 ± 2.2 years. The mean age of corneal graft was 17.6 ± 11.4 years (range 4.3–42), and the mean interval between PK and initial contact lens fitting was 12.2 ± 10.7 years (range 0.7–36.0). The average steepest keratometry of our cohort was 55.0 ± 7.5 diopter (D) and the refractive astigmatism was 8.0 ± 4.4 D. The mean contact lens corrected visual acuity (BCVAcl) was 0.78 ± 0.25 (range 0.3–1.2). Twenty-three (82%) patients achieved a functional vision of 0.5 or more.During the studied period, ten (30.0%) eyes presented at least one graft rejection episode and two eyes (6%) had an episode of microbial keratitis. Corneal transplants of 20 years or more show a higher rate of refits due to ectasia recurrence.ConclusionsScleral lenses should be considered as lens of choice in eyes with complex corneal geometry, as besides visual rehabilitation, their use may delay or prevent further surgical involvement.     

Multicenter review of impression-based scleral devices

ObjectiveTo describe outcomes using impression based-scleral devices for the management of anterior segment disease.MethodsRetrospective chart review identified all patients who were fitted with impression-based scleral devices between January 1, 2013 and June 30, 2019 at three specialty contact lens practices. Patient demographic data, indication for device use, visual and physiological outcomes, as well as details of the fitting process and survival of device use were determined.ResultsForty-four patients (70 eyes) were included in the study. Primary indications for device use included corneal irregularity (28 patients, 44 eyes) and ocular surface disease (16 patients, 26 eyes). Fifty-four percent of patients had more than one ocular surface condition, and 39 % of patients had undergone at least one anterior segment surgical procedure. Twenty-nine patients had unsuccessfully attempted to wear standard scleral lenses prior to being fit with impression-based devices. Visual acuity improved significantly with impression-based devices compared to habitual correction (p < 0.001). Completion of the fitting process (including visit to acquire the impression and post-fitting assessments) required an average of 4 [1.5] visits.Ideal haptic alignment was achieved with 74 % and complete limbal clearance was achieved in 83 % of fits. Device use was discontinued due to complications in two eyes.ConclusionPatients with complex eye disease who are unable to successfully wear standard scleral lenses successfully may achieve visual and therapeutic success with impression-based devices.     

Scleral contact lenses in the pediatric population—Indications and outcomes

PurposeTo report the use of a custom-designed, scleral contact lens (SL) in the treatment of pediatric patients.MethodsThe medical records of all patients under 15 years of age fitted with SL from March 2018 through February 2020 were retrospectively reviewed. Ophthalmic diagnosis, prior surgical intervention, lens wearing failures, and duration of lens use are reported.ResultsLenses were dispensed to 18 patients (24 eyes). Main indications for SL fitting were refractive error correction (n = 18: keratoconus (KCN), traumatic corneal scarring, corneal transplant status, and aphakia) and ocular surface protection and optimization (n = 6: neurotrophic keratitis and chronic blepharokeratoconjunctivitis). Patient age ranged from 16 months to 14 years (mean, 9.9 ± 3.5 years (mean ± standard deviation (SD)). Patients fitted for surface disease indications were significantly younger, 8.8 ± 2.5 years. The mean maximal keratometry reading in patients with keratoconus was 64.0 ± 12.6 diopters (D). In six eyes with advanced KCN (Kmax 71.8 ± 11.0 D) and three eyes with traumatic scarring, SL use obviated the need for keratoplasty. Fifteen patients (83 %) continued scleral lens wear with a mean follow-up period of 9.2 ± 7.4 months. Complications included one case of corneal graft rejection and one corneal abrasion associated with lens insertion.ConclusionsThe goals of SL fitting in pediatric patients are visual rehabilitation and ocular surface protection. Pediatric patients with advanced keratoconus and traumatic corneal scarring are most appreciative of the benefits of scleral lenses. The challenges associated with SL fitting and the training process did not preclude long-term SL wear.     

Corneal surface wettability and tear film stability before and after scleral lens wear

PurposeThe aim of this study was to evaluate the anterior surface of scleral contact lens and ocular surface wettability before and after one-month of scleral lens wear in patients with keratoconus.MethodsForty-nine patients with keratoconus (36.26 ± 9.03 years) were recruited. The sample was divided into two groups: patients with intrastromal corneal ring (KCICRS group) and patients without ICRS (KC group). TFSQ, Schirmer I test, Ocular Surface Disease Index (OSDI questionnaire), tear break-up time (TBUT) and corneal staining were evaluated in two different visits: Baseline (before lens wear) and one-month visit (10 min after lens removal). Visual Analog Scale (VAS questionnaire) was filled in just after inserting the lenses and just before removing them. TFSQ mean and inferior were evaluated over the contact lens surface at the moment of inserting the lens (baseline visit) and after 8 h of lens wear (one-month visit).ResultsAnterior corneal surface TFSQ values increased in all groups after scleral lens wear (p < 0.05). However, there were no statistical differences found at the moment of inserting or after 8 h of lens wear on previous contact lens surface TFSQ (p > 0.05). No changes were found in tear volume for total and in KC and KCICRS groups (p > 0.05). For all groups, there was a statistical decrease of TBUT (p < 0.05). In addition, OSDI score, corneal staining and VAS score improved after scleral lens wear from baseline in total and in both KC and KCICRS groups (p < 0.05).ConclusionThe scleral contact lens surface keeps its wettability after one-month of wear. However, the wettability of the ocular surface is worse after contact lens wearing.     

The corneoscleral shape in keratoconus patients with and without specialty lens wear

PurposeTo evaluate differences in corneoscleral shape in keratoconus patients with and without specialty lenses compared to controls.MethodsA cross-sectional study was performed comparing three groups of keratoconus eyes: 24 lens-naïve keratoconus eyes (17 patients; group 1), 7 eyes with corneal lens wear (7 patients; group 2) and 7 eyes with scleral lens wear (7 patients; group 3). For comparison, 25 eyes of 25 emmetropic participants and 11 eyes of 11 astigmatic participants were included. Corneoscleral topography measurements taken with the Eye Surface Profiler (ESP, Eaglet Eye BV, Houten, Netherlands) were exported and assessed using custom-made software to demarcate the limbal radius, and to calculate sagittal height and corneoscleral asymmetry.ResultsIn non-lens wearing keratoconus patients, sagittal height was found to be significantly larger than in control eyes, in both the corneal periphery and sclera (paired t-test, pairwise comparisons p < 0.01). The level of peripheral corneal and scleral asymmetry was also significantly higher in non-lens wearing keratoconus eyes compared to controls (t-test, p < 0.01). Both corneal and scleral lens wear resulted in significant changes to the shape of the corneal periphery and sclera. In all 3 groups of keratoconus eyes, asymmetry of the peripheral cornea showed a very strong correlation with scleral asymmetry (R² = 0.90, 0.86 and 0.85 for groups 1–3, respectively).ConclusionThe corneal periphery and sclera have a distinctly different shape in keratoconus eyes compared to controls. Specialty lens wear induces significant regional changes to the shape of the anterior eye in keratoconus eyes.     

Changes in corneal thickness,corneal volume,and densitometry after long-term orthokeratology wear

PurposeTo investigate changes in the corneal volume, corneal densitometry and pachymetry of young myopes wearing over-night orthokeratology (OK) contact lenses.MethodsThe medical records of 28 right eyes of young myopes wearing OK between 2013 and 2018 were reviewed retrospectively. The baseline refractive error, best corrected visual acuities at baseline and uncorrected visual acuity at the most recent visit were recorded. Corneal volume of the central 10 mm cornea; densitometry at central, nasal and temporal cornea; and pachymetry along the horizontal and vertical meridians were collected from the Pentacam® HR at baseline, after one night of lens wear, and at the latest visit.ResultsThe mean age of subjects was 12.03 ± 3.80 years at the time of OK lens fitting and wore OK overnight for a mean duration of 666 days (range 206–1736 days). The baseline spherical equivalent refractive error was ?3.03 ± 1.56 D (range ?1.00 to ?6.00 D). The corneal volume increased significantly after OK wear (p = 0.001). Corneal densitometry increased after OK wear, but the change did not reach statistical significance (p = 0.113). Pachymetry in the central cornea did not change significantly across all visits (p > 0.05) but increased significantly in the mid-peripheral regions of the cornea. Baseline refractive error was not found to be correlated with the changes in corneal volume, corneal densitometry, or pachymetry.ConclusionThe increase in corneal volume and densitometry and no significant change in the central corneal thickness may indicate the presence of corneal oedema from long-term OK wear. The baseline refraction was not correlated with the changes in corneal volume, densitometry or pachymetry.     

Utility of a semi-scleral contact lens design in the management of the irregular cornea

ObjectivesTo evaluate the utility of the Rose K2 XL semi-scleral contact lens (Menicon Co. Ltd., Nagoya, Japan) in the management of the irregular cornea.MethodsTwenty-seven subjects (34 eyes) with irregular corneas referred for contact lens fitting were evaluated. A diagnostic trial set was used in the fitting process. Once the trial lens was considered optimal, a final lens was ordered from the manufacturer with the necessary changes in power, edge lift and diameter. We analyzed visual acuity, number of lenses ordered and patients’ ability to wear and handle lenses.ResultsTwenty-three subjects (30 eyes) were fitted with the Rose K2 XL lens. Four subjects (4 eyes) decided not to conclude the fitting process for different reasons. Average logMAR visual acuity without correction and with the lens was 0.82 and 0.09, respectively (p < 0.001). An average of 1.4 ordered lenses (range 1–3) were necessary to achieve the optimal fit. Nineteen eyes (63%) were fitted with the first lens ordered. Three subjects (13%) had problems with lens handling, and three subjects (4 eyes) abandoned the wear of the lenses after three months due to discomfort (3 eyes) and unsatisfactory visual acuity (1 eye), respectively. Follow-up ranged from 6 to 9 months.ConclusionRose K2 XL semi-scleral contact lens provides good visual acuity and comfort in patients with irregular corneas.     

Rehabilitation of vision disabling corneal opacities: Is there hope without corneal transplant?

ObjectiveTo evaluate the efficacy of contact lenses in visual rehabilitation of a series of patients with corneal scars/opacities.MethodRetrospective review of case records of 158 patients (n = 162 eyes) with poor vision subsequent to corneal scar/opacity, who underwent contact lens fitting, was done. Primary outcome assessed was quantum of additional improvement in vision with rigid gas permeable (RGP) or soft lenses over spectacles. Success was defined as visual improvement of ≥2 lines over that of spectacles and/or improvement of vision to ≥20/60 (LogMAR 0.48).ResultsRigid gas permeable lenses were fitted in 137 eyes and soft contact lenses in 25 eyes. Lenses were successful in improving visual acuity by two or more lines over that of spectacles in 70% eyes (113 of 162 eyes), of which RGP lens accounted for 85% (96 of 113 eyes). Alternative outcome of success was defined as attainment of reasonable functional vision of >20/60 (LogMAR 0.48). This could be achieved in 65% cases (105 of 162 eyes) of which 83% (88 eyes) were with use of RGP lenses. Almost one-fourth (23.4%) patients were children less than 15 years old. Soft contact lenses were attempted in 25 instances, where RGP lens could not be fitted and were successful in 17 (68%) of these. All these 17 patients were aphakes.ConclusionsRehabilitation of corneas with visually disabling corneal opacities is possible with usage of appropriate contact lenses even in young children.