Scleral Lens Wear Research Articles

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.

Corneal tissue properties following scleral lens wear using Scheimpflug imaging.

PurposeTo investigate the effect of short‐term scleral lens wear on the corneal stroma at a macroscopic (thickness) and microscopic (within tissue) level, including regional variations.MethodsFourteen young, healthy participants wore a rotationally symmetric, 16.5 mm diameter, scleral lens for 8 h. Scheimpflug images were captured before, and immediately after, lens wear, and also on a second day (without lens wear) to quantify natural corneal diurnal variations. After corneal segmentation, pixel intensities of the stromal tissue were statistically modelled using a Weibull probability density function from which parameters α and β were derived.ResultsBoth α and β parameters increased significantly following scleral lens wear (by 5.7 ± 10% and 6.5 ± 6.5%, respectively, both p < 0.01). Corneal thickness also increased slightly following lens wear (mean increase 0.49 ± 1.77%, p = 0.01); however, the change in α and β parameters did not correlate with the magnitude of corneal swelling. On the control day, small but significant corneal thinning was observed (−0.82 ± 1.1%, p = 0.03), while α and β parameters remained stable. Both microparameters varied significantly across the cornea, with α decreasing (−15.4 ± 0.7%) and β increasing towards the periphery (+4.4 ± 2.6%) (both p < 0.001).ConclusionCorneal microparameters α and β varied regionally across the cornea and displayed a statistically significant increase following short‐term scleral lens wear, but remained stable between morning and evening measurements taken during a control day without lens wear. These corneal microparameters may be a useful metric to quantify subclinical corneal changes associated with low level hypoxia.

The Effect of Scleral Contact Lens Wear on Tear Osmolarity

Purpose: To measure the effect of scleral contact lens wear on tear osmolarity. Methods: A total of 31 healthy subjects were screened for inclusion in the study. All subjects have never worn scleral contact lenses. After discontinuing current contact lens wear for one week, baseline tear osmolarity measurements were taken with the TearLab Osmolarity System (TearLab Corp., San Diego, CA). Twenty-three subjects were fit with the Valley Custom Stable (Valley Contax, Springfield, OR) mini-scleral contact lens design. Once an acceptable fit was achieved, the contact lenses were dispensed for daily wear use only. At the one month follow-up visit, tear osmolarity was remeasured under the same baseline conditions. A total of 13 subjects completed the study. Results: We analyzed the data from twenty-six eyes of 13 subjects. The mean baseline tear osmolarity value was 293.58 +/- 8.49 mOsm/L. After 1 month of scleral contact lens wear, the tear osmolarity increased to 310.65 +/- 17.46 mOsm/L, which was statistically significant (p &lt; 0.001). Conclusions: Results were consistent with similar studies involving other contact lens modalities. A statistically significant increase in tear osmolarity was noted at the one month visit. It is hypothesized that this increase is caused by the disruption of the natural tear layer and, potentially, decreased tear production. 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. Click here to Enroll (https://www.crojournal.com/the-effect-of-scleral-contact-lens-wear-on-tear-osmolarity) Please check COPE course expiry date prior to enrollment. The COPE course test must be taken before the course expiry date.

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.

Intraocular pressure changes in neophyte scleral lens wearers: A prospective study

PurposeTo examine the variation in intraocular pressure (IOP) during the first six months of scleral lens wear. MethodsThirty-two neophyte scleral lens wearers were recruited and IOP was measured using Goldman applanation tonometry before, and after 1 and 6 months of scleral lens wear (following lens removal). All scleral lenses were designed based on scleral topography or an impression of the ocular surface. Central corneal thickness and the central post-lens fluid reservoir thickness were quantified using optical coherence tomography. ResultsPost-lens removal IOP displayed an increasing trend after 1 and 6 months of lens wear, but the magnitude of change was not clinically or statistically significant using several repeated measures analyses to account for sporadic missing longitudinal data (mean increase of 1 mmHg or less, p > 0.05). Central corneal thickness and the central post-lens fluid reservoir remained stable throughout the first six months of lens wear. ConclusionIOP measured following lens removal did not vary significantly during the first 6 months of lens wear in scleral lens neophytes. Further research is required to determine if IOP varies during lens wear, following lens removal, or after longer-term lens wear due to suction forces or tissue compression beneath the landing zone.

Scleral lens wear following penetrating keratoplasty: changes in corneal curvature and optics.

Visual rehabilitation following penetrating keratoplasty is the primary indication for approximately 15% of all scleral lens fittings. Since corneal biomechanics are altered following penetrating keratoplasty, the aim of this study was to quantify changes in anterior corneal optics following short-term scleral lens wear in eyes with corneal grafts. Scheimpflug images were obtained before and after a period of scleral lens wear (mean 6.3±1.4h), from eyes that had previously undergone penetrating keratoplasty (10 eyes of nine participants, mean age 31±9years). Corneal power and thickness data were examined over the central 6mm, including regional analyses of the central (0-3mm) and the mid-peripheral cornea (3-6mm annulus) using customised software to deterime corneal power vectors M (best fit sphere), J0 (90/180 astigmatism) and J45 (45/135 astigmatism). Anterior corneal aberrations were extracted using corneal elevation data. Corneal power vector J45 increased following lens wear (by 0.22±0.05 D, p=0.003) across the central 6mm, while M displayed regional variations following lens wear indicating larger changes further from the corneal centre (p=0.004). The change in corneal power vector M was also correlated with the magnitude of central corneal swelling (r=0.65, p=0.04). The anterior corneal aberration terms of oblique astigmatism, hoirzontal coma, and spherical aberration also varied following lens wear (all p≤0.01). The mean change in the corneal spherocylinder derived from the elevation data following lens wear was +0.14/-0.54×44 for a 6mm corneal diameter. Clinically significant alterations in anterior corneal topography and higher order aberrations were observed following short-term scleral lens wear in eyes that had undergone penetrating keratoplasty. Spherocylindrical changes were approximately double the magnitude and more oblique in orientation compared to previous reports of healthy eyes. Changes in corneal power vector M may be related to epithelial corneal oedema.

Factors associated with patient-reported midday fogging in established scleral lens wearers

PurposeTo estimate the prevalence of patient-reported midday fogging and to identify risk factors for midday fogging. MethodA multicenter, cross-sectional study was conducted with an electronic survey that was distributed to scleral lens practitioners. The survey asked them to describe their most recently examined established scleral lens patient. Respondents provided data about patient-reported midday fogging, patient demographic characteristics, indication for lens wear, lens-wearing schedule, lens design, and care products. ResultsOf the 248 survey respondents who indicated whether their patients had midday fogging, 64 (25.8 %) had patients who self-reported such issues. Midday fogging was not associated with demographic characteristics (age, sex, race/ethnicity), indications for scleral lens wear, mean lens diameter (P = .30), haptic design (P = .29), use of a daily cleaner (P = .12), disinfection/storage solution used (P = .71), or filling solution (P = .65). Patients who reported midday fogging more commonly reported redness or irritation associated with scleral lens wear compared with those who did not experience midday fogging (P = .03). ConclusionsPrevalence of midday fogging in this study was similar to previously reported rates. No specific lens design or care product was associated with patient-reported midday fogging. If inflammatory mediators are elevated in the postlens fluid reservoir of patients with midday fogging, as previously described, the redness or irritation associated with scleral lens wear suggests that ocular surface inflammation may be contributing to this phenomenon.

Scleral lens wear: Measuring inflammation in the fluid reservoir

PurposeTo measure inflammatory mediators in the scleral lens fluid reservoir (FR) in healthy eyes and to compare them to basal tear samples after 8-hs (8h) and 4-days (4d) of scleral lens (SL) wear. MethodsFifteen normal, habitual soft contact lens wearers were fitted with 14.8- or 15.4-mm SLs (Zenlens, Alden Optical, USA). Basal ocular surface tears and FR samples were collected after 8h and 4d of daily SL wear. Levels of interleukin (IL) -4 and -8, matrix metalloproteinase (MMP)-7, -9, and -10, and tissue inhibitor of MMPs (TIMPs) 1–4 were measured in all samples using Luminex assays. Visual acuity, corneal and conjunctival staining, and comfort assessments were completed at the baseline, 8h and 4d time points. ResultsMMP-9 and MMP-10 were greater in FR than basal ocular surface tears. After 8h of SL wear, the median concentration of MMP-9 in the FR and basal tears were 62.7 and 15.2 ng/mL, respectively (p = 0.047). Likewise, MMP-10 was significantly greater in FR compared to basal tears, after 8h (25.8 ng/mL vs 2.8 ng/mL, p < 0.001) and 4d (2.1 ng/mL vs17.2 ng/mL, p = 0.047). IL-4 and IL-8 levels were greater in FR but not significantly at 8h (2.2 vs 3.1 ng/mL; and 0.1 vs 0.4 ng/mL, respectively) or 4d (0.9 vs 3.5 ng/mL; 0.0 vs 0.2 ng/mL). MMP-7 was not affected by SL wear after 8h (46.0 basal vs 54.4 ng/mL FR) or 4d (34.2 vs 87.5 ng/mL). Visual acuity, corneal and conjunctival staining did not change; comfort was reduced in SL compared to soft contact lens wear. ConclusionsThis is the first study to compare the FR with the basal ocular surface tears. MMP-9 and MMP-10 were elevated in the FR after several hours of SL wear, suggesting potential clinical implications of SL wear and deserves further investigation.

Bacteriostatic Effect of Multidose Preservative-free Buffered Saline Used in Scleral Lens Wear.

Scleral lenses have become an increasingly common treatment for ocular surface disease and irregular corneas. Multidose, preservative-free saline solutions are frequently used off-label to fill scleral lenses. Because the fluid resides over the ocular surface during lens wear, contaminated solutions may increase the risk of infectious complications. We sought to assess the viability of skin microorganisms and pathogens associated with keratitis once introduced into a multidose preservative-free saline (MDPFS) solution containing the bacteriostatic agent boric acid (PuriLens Plus; The Lifestyle Co., Inc., Freehold, NJ). Eleven bacterial and one yeast isolate were each inoculated to three lots of MDPFS as well as to sterile normal saline for comparison. Microorganism concentrations were enumerated at baseline and days 1, 3, 7, 14, 21, and 28. Persistence of microorganism viability was compared between MDPFS lots and between MDPFS and normal saline for each organism. Duration of microorganism viability was ≥24 hours in MDPFS with no significant difference in the distribution of survival duration of microorganisms in MDPFS versus normal saline (P = .15). Candida albicans concentrations declined 14 days earlier in MDPFS, whereas concentrations of viable organisms in MDPFS remained within 1 log of baseline for the longest durations for Pseudomonas aeruginosa (7 days), Escherichia coli (14 days), and Achromobacter xylosoxidans (≥28 days). Gram-positive organism concentrations remained within 1 log of baseline for no more than 3 days. Mild lot-to-lot variation in organism concentrations was noted near the end points of viability. Bacteriostasis was demonstrated in that concentrations of all organisms remained at or below baseline levels throughout the 28-day period. After microbial contamination, persistence of organism viability was similar in PuriLens and normal saline. Environmental gram-negative organisms, many of which can contribute to infectious keratitis, can persist for weeks once introduced into saline solutions.

The impact of short-term fenestrated scleral lens wear on intraocular pressure

PurposeTo examine the influence of short-term fenestrated scleral lens wear on intraocular pressure (IOP) in healthy eyes. MethodsIOP was measured before, during, and after a brief period (1–2 min) of fenestrated, scleral lens wear, using a rebound tonometer, in fifty, young healthy adults (mean age 23 ± 4 years) with normal corneas. ResultsImmediately following lens insertion, 48 of the 50 (96 %) of participants displayed an increase in IOP (mean ± SD increase in these participants of 3.8 ± 2.0 mmHg). Immediately following lens removal, 50 % of participants displayed a reduction in IOP, equal to or lower than, the pre-insertion IOP (-1.0 ± 0.8 mmHg lower than baseline). The remaining 50 % of participants displayed an IOP slightly greater than the pre-insertion IOP (1.6 ± 1.0 mmHg greater) after lens removal. ConclusionsShort-term fenestrated scleral lens wear resulted in a small, but statistically significant, increase in IOP in 96 % of young healthy participants (< 4 mmHg on average), which decreased to a level similar to pre-lens insertion IOP levels immediately following lens removal. Further research is required to determine if this measured change in IOP during scleral lens wear is artefactual, or an elevation in the true IOP.

Central corneal clearance during longer-term scleral contact lens wear

Central corneal clearance during longer-term scleral contact lens wear

Regional Variations in Postlens Tear Layer Thickness During Scleral Lens Wear.

To quantify regional variations in the postlens tear layer (PLTL) thickness during scleral lens wear. Fifteen healthy adults (22±3 years) with normal corneae were fitted with a 16.5-mm-diameter rotationally symmetric scleral lens in one eye. The PLTL thickness was measured across the central 5 mm at 0, 15, 30, 45, 60, 90, 120, 240, and 480 min after lens insertion using a 12 radial line scan optical coherence tomography imaging protocol. Regional analyses were conducted by dividing the PLTL into 8 equal 45° segments. A tilted optic zone was observed immediately after lens insertion with the greatest PLTL asymmetry between nasal and temporal regions (156±22 μm more clearance temporally) and superior nasal and inferotemporal regions (124±12 μm more clearance inferotemporally). The magnitude of lens settling observed in each region was associated with the initial PLTL (r=0.59-0.77, P≤0.02). The superior nasal PLTL furthest from the pupil center stabilized after 90 min compared with other regions which stabilized after 4 hr. On average, after 8 hr of lens wear, the PLTL decreased by 29% and PLTL asymmetries between opposing regions decreased by 30%. The PLTL was thickest temporally and thinnest nasally in healthy eyes fitted with rotationally symmetric scleral lenses, most likely because of regional differences in underlying scleral elevation, eyelid forces, and lens centration. Postlens tear layer asymmetries diminished with lens wear, and stabilization occurred more rapidly in regions with less corneal clearance immediately after lens insertion.

Clinical Findings and Ocular Symptoms Over 1 Year in a Sample of Scleral Lens Wearers.

To report the fitting aspects, clinical findings, and symptoms over 12 months of scleral lens (SL) wear. Sixty-nine patients with irregular cornea due to ectasia or surgical procedures (IC group) or regular corneas with high ametropia (RC group) completed the 12-month prospective follow-up period. Patients were evaluated at baseline, lens dispensing visit, 1 month, 3 months, 6 months, and 12 months for assessment of comfort, fitting aspects, and slitlamp findings. Comfort was assessed with the Ocular Surface Disease Index (OSDI) questionnaire and Dry Eye Questionnaire. Slitlamp evaluations comprised on-eye lens fitting (lens alignment and tear reservoir thickness) and anterior ocular surface health after removing the lens (edema, hyperemia, staining, and adverse events). OSDI Scores were significantly reduced after 1 month of SL wear comparing to baseline (from 47.0±22.7-23.9±14.7 in IC group, P<0.001 and 27.0±16.1-17.0±13.7, P=0.029 in RC group, P<0.05), without statistical significant differences from 1 to 12 months. Tear reservoir thickness showed a significant reduction at V1m (122 μm on IC group and 126 μm in RC group, P<0.05), that continued over time until V12m (195 and 184 μm lower compared with Baseline (P<0.05, Wilcoxon). Hyperemia and staining were significantly higher after SL removal when compared with baseline (P<0.05), and maintained the same behavior over the 12 months. There were no severe adverse events during the entire follow-up period. Comfort enhancement promoted by SL remained over the entire follow-up. Despite no severe adverse events recorded over the 12 months of follow-up, higher hyperemia and staining grades were found after SL removal when compared with no-lens condition.

A one-year prospective study on scleral lens wear success

PurposeTo report the success rate of scleral lens wear and the lens handling learning curve from the wearers perspective. MethodsNinety-five participants were consecutively screened for enrollment in a prospective study. Participants were divided into two groups: ICGroup (71 participants with irregular corneas) and RCGroup (24 participants with regular corneas). Participants attended several visits: Baseline, Lens Dispense Visit (LDV), 1-month, 3-month, 6-month and 12-month follow-ups. The number and causes of scleral lens discontinuation and the time to correctly apply the lens for the first time at the LDV were evaluated. During follow-ups, participants answered a questionnaire regarding scleral lens wear (mean number of hours/day and days/week of lens wear, methods used for handling, number of attempts to correctly apply and remove the lenses). ResultsSixty-nine participants (73 %) successfully completed the 12-month period. Twenty-six participants (27 %) discontinued scleral lens wear. None of the discontinuations were due to adverse events. The success rate (number of participants that wore the lenses for the 12 months) was 77 % in ICGroup and 58 % in RCGroup. The main reasons for scleral lens discontinuation were handling issues (35 %) and discomfort (19 %). 36 % of participants required <15 min to correctly apply the lens at the LDV, however 13 % required >60 min (participants that wore spectacles, soft lenses or had no correction method at Baseline). The mean wearing time (hours/day and days/week) increased significantly from 1-month to 12-month appointments: from 9.8–11.1 h and 5.1–5.6 days in new scleral lens wearers, while the number of attempts to correctly apply and remove the lenses decreased significantly. ConclusionsThe success rate was 73 % during this prospective 12-month follow-up study. The main reasons for drop-out were handling issues and discomfort. Participants who continued scleral lens demonstrated increased handling skills.

Corneal Endothelial Blebs Induced in Scleral Lens Wearers.

In the bleb phenomenon, some endothelial cells transiently lose their specular reflection. This has been reported during contact lens wear and goggle-induced hypoxia or hypercapnia. The purposes of this study were to determine whether blebs appear after scleral lens wear and if their appearance is influenced by lens clearance and to compare bleb and cell sizes. Twenty-one subjects were fitted with two similar scleral lenses with different targeted clearances of 200 and 400 μm (the SL200 and SL400, respectively). Each lens was worn unilaterally for 25 minutes, whereas the other eye served as a control. Before and after lens wear, the endothelium was photographed using specular microscopy. The number of blebs and measurements of the areas of cells and blebs were analyzed. Paired t tests compared differences in the areas of cells and blebs. Differences in median bleb number were evaluated using the Wilcoxon test. After wearing the SL200 and SL400 lenses, respectively, 9 and 14 subjects had at least one bleb. The median bleb number after wearing lenses was significantly different (SL200, 0.00; SL400, 1.00; P = .02). Bleb and cell areas were significantly different (blebs, 293 ± 28; cells, 370 ± 32 μm; P < .0001). After 25 minutes of wearing scleral lenses with each of the two targeted clearances, SL400 induced significantly more blebs than did SL200, suggesting evidence of reduced oxygen and/or increased carbon dioxide levels under scleral lenses fitted with excessive clearance. Blebs may occur more in smaller cells.

Effect of Scleral Lens Wear on Central Corneal Thickness and Intraocular Pressure in Patients With Ocular Surface Disease.

To determine the effect of scleral lens wear on central corneal thickness (CCT) and intraocular pressure (IOP). Twenty-five subjects (46 eyes), fit with scleral lenses that ranged in diameter from 17.0 to 18.0 mm, were included in this retrospective study at the University of Southern California, Department of Ophthalmology. All subjects had ocular surface disease and were categorized into the following groups based on etiology of their dry eye: chronic graft versus host disease, Stevens-Johnson syndrome, Sjögren syndrome, or general dry eye syndrome. Measurements of CCT and IOP were obtained at the initial scleral lens consultation (pre-CCT and pre-IOP) and at follow-up visits (post-CCT and post-IOP) immediately after lens removal. The total average difference between pre-CCT and post-CCT was 7.19 μm (544.90±31.29 vs. 552.09±30.30 μm), which was a statistically significant increase of 1.01% (P≤0.05). On the other hand, the total average difference between pre-IOP and post-IOP was -0.89 mm Hg (14.47±3.63 vs. 13.58±3.61 mm Hg), which was not statistically significant (P≥0.05). There were no statistically significant correlations between change in CCT (ΔCCT) and visual acuity (P≥0.05), between ΔCCT or change in IOP (ΔIOP) in relation to lens diameter (P≥0.05), between etiology of dry eye affecting ΔCCT or ΔIOP (P≥0.05), between wearing time today and ΔCCT or ΔIOP (P≥0.05), and between average wearing time (AWT) and ΔCCT (P≥0.05). In addition, there was no statistically significant correlation between AWT and ΔIOP (R=0.0796) over a range of wear time hours. There was a statistically significant increase in CCT after scleral lens wear in subjects with ocular surface disease, which may be attributed to subclinical hypoxic conditions created by scleral lens wear. No significant relationship was found between scleral lens wear and IOP.

Epithelial Inclusion Cyst of the Bulbar Conjunctiva Secondary to Scleral Lens Impingement Managed With a MicroVault.

Acquired epithelial inclusion conjunctival bulbar cyst is a reported complication of scleral contact lens impingement commonly corrected with a diameter change or notch of the scleral contact lens. This case discusses an acquired epithelial inclusion conjunctival bulbar cyst due to microtrauma caused by prolonged scleral contact lens wear and corrected with a MicroVault.

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.

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.

Anterior Corneal Curvature and Aberration Changes After Scleral Lens Wear in Keratoconus Patients With and Without Ring Segments.

To evaluate changes in the anterior corneal curvature and aberrometry after scleral contact lens wear in keratoconus (KC) subjects with and without intracorneal ring segments (ICRS). Twenty-six subjects diagnosed with keratoconus were selected to participate in the study. Subjects were divided into 2 groups, those with ICRS (KC-ICRS group) and those without ICRS (KC group). Subjects were instructed to wear 16.5-mm scleral lenses for 8 hours. Topographic and aberrometric parameters were evaluated before lens wear and immediately after lens removal. Anterior corneal curvature was evaluated at corneal diameters of 2, 4, 6, and 8 mm, and corneal aberrations were measured at 4-, 6-, and 8-mm pupil diameters. The mean age of subjects was 36.95±8.95 years. In KC group, there was a statistically significant flattening of the central corneal curvature, from 6.98 to 7.09 mm (P<0.05). No changes were found in the central corneal curvature in the KC-ICRS group. The KC group showed anterior corneal curvature flattening, mainly in the nasal quadrant. The KC-ICRS group showed flattening primarily in the inferior hemisphere. In the KC group, spherical aberration for 6-mm pupil increased significantly. In the KC-ICRS group, changes in aberrations were significant for high-order root mean square at 4- and 6-mm pupil diameters (P<0.05), for oblique astigmatism for 4 mm and 6 mm, and for vertical coma for 4-mm pupil (P<0.05). Short-term scleral lens wear showed flattening of the anterior corneal surface in all subjects. In the KC group, the flattening was more pronounced in the nasal quadrant while changes were more pronounced inferiorly in KC-ICRS group.