Improved contact lens fitting after corneal cross-linking in eyes with progressive keratoconus

ObjectivesThe study aimed to assess the possible effects of corneal cross-linking (CXL) on contact lens (CL) fitting in patients with progressive keratoconus who initially had CL intolerance.MethodsA retrospective review was performed of the medical records of patients who had stopped CL wear due to discomfort prior to CXL and who were fitted with CLs after CXL. All eyes were evaluated pre- and 1, 6, 12, 24 months postoperatively. Data collected included pre- and post-CXL refraction, corneal topographic data, uncorrected visual acuity, and best-corrected visual acuity (BCVA). CL comfort was evaluated using the Likert scale post-CXL.ResultsA total of 20 eyes from 14 patients were included in the study. Preoperative Kmax values significantly decreased by 2.8 D at 6 months and by 4.1 D at 12 months after CXL (p < 0.001 for both). CLs were prescribed on average 12 ± 2.5 months after CXL. The mean duration of successful CL wear was 10.4 ± 2.8 months during the follow-up period. Subjective CL comfort scores were satisfactory post-CXL.ConclusionCXL not only halts the progression of keratoconus but may also improve CL tolerance by providing a more regular shaped cornea in these patients. Ongoing corneal topographic changes in the late postoperative period after CXL may have a positive effect on CL fitting.     

Reverse geometry contact lens fitting in corneal scar caused by perforating corneal injuries.

PURPOSE: To describe a reverse geometry rigid gas permeable (RGP) contact lens fitting in corneal scar caused by perforating corneal injuries with intraocular strange body. METHODS: A reverse geometry RGP lens, with large diameter, was empirically fitted in a 38-year-old male patient who had previous open globe injuries due to work accident in right eye. Corneal suture, vitrectomy and lens extraction were performed. Irregular corneal surface with corneal scar in line with the visual axis were found with low uncorrected visual acuity. RESULTS: Snellen visual acuity improved from counterfinger to 0.8 with high contact lens acceptance, 6-9h per day of wear. Only three diagnostic contact lenses, in two visits, were necessary. Orbscan simulated fluorescein pattern was different to definitive fluorescein pattern. CONCLUSIONS: Reverse geometry RGP contact lens, with large diameters, could be a good alternative in irregular corneal surface with corneal scar. Fluorescein pattern analysis could be the proper fitting technique. This fitting could involve less time and fewer visits. Computer-aided fitting was of limited value in these cases.     

The application of a computerised videokeratography (CVK) based contact lens fitting software programme on irregularly shaped corneal surfaces.

PURPOSE: To explore the success of the application of a computerised videokeratography (CVK) software system for the fitting of rigid gas permeable (RGP) contact lenses (CLs) on irregular corneal surfaces and compare it to the standard diagnostic fitting procedure. METHODS: This was a comparative prospective study, over a 1-year period (2004-2005). It included 41 RGP CL wearers (68 eyes) with irregular corneal surfaces. Of these, 51 (75%) had keratoconus, 7 (10%) corneal scarring (infectious or traumatic), 6 (6.82%) corneal transplants, 2 (2.9%) astigmatism, and 2 (2.9%) aphakia. Each eye was being re-fitted with a new RGP CL based on a topographical measurement in conjunction with a CL fitting software programme. The performance of the CLs was evaluated regarding visual outcome, fitting characteristics, and efficiency of the fitting procedure. RESULTS: Of the 68 eyes, 53 (77.94%) chose the CL fitted using the CVK software system, 9 (13.24%) chose the CL fitted using the standard procedure, and 6 (8.82%) showed no preference for either CL. There was a statistically significant improvement regarding visual outcome [contrast sensitivity at the spatial frequencies of 0.66 (p=0.029), 3.40 (p=0.008), and 17 (p=0.032), subjective vision (p=0.009)], fitting characteristics [grading scale (p=0.00), lens comfort (p=0.00) and daily wearing time (p=0.002)], and efficiency [number of trial lenses required (p=0.00)] with the CL fitted using the CVK software system. Correlating factors for the likely preference for the CL fitted using the CVK software system were subjective vision (p=0.004), lens comfort (p=0.009), and convenience of the fitting procedure (p=0.023). CONCLUSION: The application of a CVK software system for the fitting procedure of RGP CLs on irregular corneal surfaces was a safe procedure and shown to be more successful and efficient than the standard diagnostic fitting method.     

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

PurposeTo assess the feasibility of fitting a lathed soft toric contact lens (STCL) after the implant of intrastromal corneal ring segments (ICRSs) to treat keratoconus.MethodsSix 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 (≤0.2 logMAR) or unsuccessful (>0.2 logMAR). 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.ResultsSTCL 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 ≤0.2 logMAR 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.ConclusionSTCL 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.     

Optical quality and intraocular scattering assessed with a double-pass system in eyes with contact lens induced corneal swelling

PurposeTo evaluate the impact of contact lens (CL)-induced corneal swelling on the optical quality of the eye by means of the double-pass technique.MethodsMeasurements of 6 healthy subjects were obtained in 5 visits over 1 week, at baseline and after sleeping with 4 different CLs of +0.50 D, +2.00 D, +5.00 D and +8.00 D (Acuvue2), randomly fitted on 4 different days. The control eye wore no CL. Corneal pachymetry and optical quality of the eye (OQAS, Visiometrics) were measured once at baseline and at three interval times in the follow-up visits: immediately after CL removal, and 1 and 2 h after CL removal. Optical quality was evaluated by means of the Strehl ratio and OQAS values at 100%, 20% and 9% contrasts. Intraocular scattering was evaluated with the objective scatter index (OSI).ResultsMean overnight swelling was 5.98 ± 4.29% in CL-eyes versus 0.30 ± 0.78% in control eyes (p < 0.01). Corneal swelling was maximal immediately after CL removal and decreased with time (p < 0.01). A significant worsening in all optical quality parameters and a significant increase of the OSI were found in eyes with corneal swelling (p < 0.05). Two hours after CL removal there were no statistically significant differences (p > 0.05) between CL-eyes and control eyes in any of the measured parameters.ConclusionsCorneal swelling has a significant impact on the optical quality of the eye and on intraocular scattering as assessed with the double-pass technique.     

Relationship of placido corneal topography data with scleral lens fitting parameters

PurposeTo analyze the relationship between corneal sagittal height and asymmetry parameters derived from Placido-videokeratoscopy with the parameters of fitted scleral lenses (ScCLs).MethodsCorneal topographies were measured with MedmontE300 in a total of 126 eyes with irregular and regular corneas before ScCL fitting were analyzed. Measurements of sagittal height (OC-SAG) at steep and flat corneal meridians were obtained for 10 mm and 12 mm chords. Estimated Height (EHChord) parameters were taken for a chord equal to the diameter of the lens that each subject was wearing at different semi-meridians. Corneal asymmetry (difference in OC-SAG between steep and flat corneal meridians) was also assessed. These outcomes were correlated to ScCL parameters that subjects were wearing after 1 month.ResultsThe mean ScCL-SAG was 4696 ± 240 μm, and the mean OC-SAG ranged from 1891 μm (10 mm), 2914 μm (12 mm), and between 4162 μm and 4251 μm for EH0-180º and EH30-210º. Stronger correlations (p < 0.001) between OC-SAG and ScCL-SAG were determined for EH0-180º (r = 0.595) and EH30-210º (r = 0.618). The mean differences between OC-SAG and ScCL-SAG were between 447 ± 290 μm (EH0-180º) and 389 ± 360 μm (EH30-210º). There was no relationship between corneal asymmetry and the need to fit a ScCL with toric haptic design in irregular corneas. Orientation of flat corneal and scleral meridians were similar only in corneas with high regular astigmatism.ConclusionsEHChord attributes were the parameters that best correlated with the ScCL-SAG. The corneal asymmetry was shown to be a poor predictor for the need to fit a ScCL with toricity at landing zone in irregular corneas, but could have some predictive power in regular corneas.     

UVB-induced epidermal pigmentation in mice eyes with no contact lens wear and non-UVB blocking and UVB blocking contact lens wear

PurposeIrradiation by ultraviolet (UV) B is known to increase the number of Dopa-positive melanocytes in the skin. This study examines the effectiveness of a contact lens for the defense of UVB eye irradiation-induced pigmentation.MethodsA 2.5 kJ/m² dose of UVB radiation was delivered by a sunlamp to the eye of C57BL/6j male mice, and changes in the expression of Dopa-positive melanocytes in the epidermis and the plasma level of alpha-melanocyte-stimulating hormone (α-MSH) was analyzed.ResultsThe degree of change in the Dopa-positive melanocytes expression was reduced by UVB blocking contact lens using mice given UVB irradiation to the eye. The plasma level of α-MSH increased in the C57BL/6j mice after irradiation to the eye, but there was no increase in the UVB blocking contact lens mice given UVB irradiation to the eye. Both the increase of the expression of Dopa-positive melanocytes and the plasma level of α-MSH were strongly suppressed by an alignment fitting UVB blocking contact lens and only a slightly suspended UVB blocking contact lens. In addition, these changes were successfully inhibited by a UVB blocking contact lens but not by a non-UVB blocking contact lens with a similar absorbance.ConclusionThese observations suggest that the UVB blocking contact lens inhibits the pigmentation of the epidermis in mice by suppressing of the α-MSH.     

Feasibility of contact lens fitting on keratoconus patients with INTACS inserts.

PURPOSE: To demonstrate the feasibility of contact lens fitting in keratoconus patients with INTACS inserts. METHODS: A chart review was conducted of all patients with bilateral keratoconus who were treated with INTACS inserts on one eye and who were subsequently referred for contact lens fitting in a university based contact lens practice between April 2000 and April 2002. The study was a retrospective, non-comparative case series. The uncorrected and best spectacle corrected visual acuity (BSCVA) after INTACS implantation surgery, postoperative best contact lens-corrected visual acuity (BCLVA), number of diagnostic contact lenses used, number of contact lenses ordered within a 4-month follow-up period, contact lens complications encountered, final base curves, final lens powers, and final wearing times were determined. RESULTS: Three keratoconic patients meeting the selection criteria were found through the chart review. Prior to surgery, all patients had uncorrected visual acuity (UCVA) of 2.0 logMAR (counting fingers). This improved to a mean of 0.81+/-0.25 logMAR (20/125-1) after surgery. Mean BSCVA also improved from 0.51+/-0.30 logMAR (20/60-2) to 0.30+/-0.16 logMAR (20/40). The mean postoperative best contact lens-corrected visual acuity was 0.02+/-0.10 logMAR (20/20-1). The number of diagnostic lenses ranged from 1 to 7. The numbers of contact lenses ordered during the 4-month follow up period ranged from 1 to 3. Two eyes were fitted with larger than usual lens designs made of rigid gas-permeable material and one eye was fitted with a toric soft lens. The final lens power ranged from +1.25 to -21.0D with a mean spherical equivalent of -7.46+/-11.89 D. Final wearing times ranged from 2.5 to 12.0h. CONCLUSION: Fitting contact lenses on keratoconus patients who have INTACS inserts is feasible and has a role in augmenting their vision.     

Treatment of corneal dellen with a large diameter soft contact lens

A 58-year-old man presented with corneal dellen twelve days after pterygium removal on his left eye. Initial treatment with lubrication and artificial tears was unsuccessful. The fitting of a conventional contact lens was not possible because of conjuctival chemosis. Additionally the patient denied eye patching due to professional reasons. As an alternative treatment a large diameter bandage soft contact lens approved for extended wear was applied ((David Thomas Contact Lens T74/85 Extended Wear/Bandage of 18 mm diameter). The next day corneal dellen had already began to retreat and four days later the contact lens was removed since there was no sign of dellen in the slit lamp examination. In conclusion, the use of a large diameter soft contact lens was an effective alternative solution for the treatment of corneal dellen in our patient.     

Intraepithelial corneal haemorrhage in a rigid contact lens wearer

Intracorneal haemorrhage is a rare complication of modern contact lens wear. While a limited number of reports have described intracorneal haemorrhages (typically stromal) associated with the extended wear of soft contact lenses with limited oxygen permeability for the correction of aphakia, this case report documents the management and resolution of a significant intraepithelial corneal haemorrhage associated with long-term rigid contact lens wear for keratoconus and high myopia.     

International survey of contact lens fitting for myopia control in children

PurposeTo determine the extent of contact lens fitting for myopia control (MC) in children (defined as ≤ 17 years of age) worldwide and to characterize the associated demographics and fitting patterns.MethodsSurvey forms were sent to contact lens fitters in 66 countries between January and March every year for eight consecutive years (2011–2018, inclusive). Practitioners were asked to record data relating to the first 10 contact lens fits performed after receiving the survey form. Data were analysed for those countries reporting ≥ 100 contact lens fits to children.ResultsData were analysed for 535 MC fits and 23,295 other (non-MC) lens fits undertaken in 31 countries reporting ≥ 100 contact lens fits to children, with 52.1% of MC fits and 12.0% of non-MC fits being with rigid lenses (p < 0.0001). Overall, MC lenses represented 2.3% of all contact lens fits to children, with significant differences between nations (p < 0.0001), ranging from no MC fits recorded in the Czech Republic, Greece, Japan, South Korea and Puerto Rico, to 24.9% in Austria. There has been an increase in contact lens fitting for MC over the survey period (p < 0.0001). MC contact lenses were fitted to younger children compared to non-MC lenses (MC, median 13 years vs. non-MC, median 15 years) (p < 0.0001). There was no sex bias in the fitting of MC lenses (p = 0.89).ConclusionsMC lenses are currently being prescribed for younger children in equal measure in terms of soft vs. rigid lenses and males vs. females. The extent of MC fitting is low and varies between nations. The gradual increase in MC fitting throughout the survey period perhaps reflects growing concerns among practitioners over the myopia epidemic.     

Soft contact lens care systems and corneal staining in Hong Kong-Chinese.

One hundred and ninety two patient files (for the year September 1995-September 1996) from the Contact Lens Clinic of The Department of Optometry & Radiography, The Hong Kong Polytechnic University were surveyed. A total of 117 patients mostly using three lens care systems (CIBA VISION AOSept, Allergan Oxysept 1-step and Bausch & Lomb Multipurpose solution (MPS)) were included in this retrospective study of the incidence of corneal staining in patients using different lens care systems. The incidence and severity of staining observed was significantly higher and worse respectively in patients using MPS than in patients using the peroxide systems. Corneal staining was observed in 32.3% of the patients using AOSept, in 17.8% of the patients using Oxysept 1-step, and in 70.7% of the patients using MPS system. However, these percentages did not take into account other factors (which we assumed to be affecting the three groups equally) which may have caused some of the corneal staining observed. Of the patients who had corneal staining: 31% (9/29) of the patients using MPS system changed to peroxide system, and 38% (11/29) of the patients were re-educated on proper lens care; 77% (14/18) of the patients using the peroxide systems did not use proper care procedures. The tear stability and volume of HK-Chinese have been reported to be low compared to those reported for Caucasians, which may render Hong Kong-Chinese soft contact lens wearers more prone to adverse reactions to preservatives and to rapid deposit formation. The majority of the patients with corneal staining did not complain of any ocular discomfort even when severe staining was observed.     

Comparison of the effect of multipurpose contact lens solutions on the viability of cultured corneal epithelial cells

Purpose

To determine the effect of four marketed multipurpose contact lens solutions (MPSs) on corneal epithelial cell viability.

Methods

Comparison of the effect of MPS A (Renu MultiPlus, Bausch &; Lomb), MPS B (OPTI-FREE Express, Alcon), MPS C (AQuify, CibaVision), and MPS D (OPTI-FREE RepleniSH, Alcon) on cell viability was performed by quantifying cellular ATP content, resazurin reduction, and lactate dehydrogenase (LDH) release in transformed human corneal epithelial cells (HCEpiC) and primary bovine corneal epithelial cells (BCEpiC).

Results

Significant reductions in cellular ATP content were observed at 40% solution and above with both MPS B and MPS D, compared to at 100% only for MPS A and MPS C, and similar results were obtained in BCEpiC. Effects on resazurin reduction were also less in HCEpiC exposed to increasing doses of MPS A and MPS C than in cells exposed to MPS B and MPS D. After 15 min, HCEpiC viability measured by both resazurin reduction and cellular ATP levels was significantly lower for cells exposed to MPS B, MPS D, and MPS C, while HCEpiC exposed to MPS A were not affected. MPS B and MPS D reduced cell viability more than MPS A and MPS C over a 2-h time course in both HCEpiC and BCEpiC.

Conclusions

Both MPS B and MPS D can cause large decreases in the viability of cultured corneal epithelial cells even with just a 2 h exposure at multiple doses. Significant reduction in cell viability is evident at brief 15-30 min exposures. In contrast, MPS A and MPS C have significantly less effect on the cell viability of corneal epithelial cells at multiple doses, after these short exposure times.     

An acute clinical comparison of corneal staining and comfort associated with contact lens care solutions

PurposeThis study compared the biocompatibility and comfort of 4 lens care solutions currently marketed in France.MethodsThis was a randomized, interventional, double-masked, single-center crossover study assessing balafilcon A silicone hydrogel contact lenses, bilaterally, straight from the blister pack solution (control) and pre-soaked in the following lens care solutions: Regard^® (containing sodium chlorite), ReNu^® (containing a PHMB [polyhexamethylene biguanide] derivative), CyClean™ and MeniCare™ Soft (both containing PHMB). Subjects were randomized to the order of test solution use. For each of the 5 solutions tested, subjects attended a baseline/lens dispensing visit and an intervention visit 2 h later. At both visits, evaluation included slit-lamp examination, corrected-distance visual acuity, corneal staining, and subject-assessed photophobia, ocular comfort, and ocular redness.ResultsThirty subjects were enrolled and 28 were evaluable. Corneal staining severity was significantly worse than baseline after 2 h of wearing lenses soaked in CyClean, MeniCare, or ReNu (P ≤ 0.001). The MeniCare group alone demonstrated a significant improvement in ocular comfort after 2 h of lens wear (P = 0.02). No group demonstrated significant changes in ocular redness or photophobia. Corrected-distance visual acuity was similar between baseline and intervention visits for each test solution. No adverse events were reported during the study.ConclusionsSilicone hydrogel contact lenses presoaked in lens solutions containing PHMB or a PHMB derivative produced an increase in corneal staining after 2 h of lens wear. The higher levels of corneal staining in the 2 solutions did not correlate with increased discomfort within this 2-h timeframe.     

Developments in corneal topographic analysis following contact lens wear and refractive surgery.

There is now a wide range of devices available for corneal topographic analysis. Although most devices use the Placido disk approach, fluorescein profilometry, laser holography and scanning slit technology have also been employed. The colour-coded topographical maps have been designed for ease of clinical interpretation. The application of this technology to further our understanding of the effects of contact lens wear and various forms of refractive surgery is demonstrated. Current developments include the merging of corneal topographic analysis and ocular wavefront sensing technology to create the capability of etching sophisticated corneal shapes in the course of refractive surgery so as to provide optimal aberration control.     

The influence of soft contact lens wear and two weeks cessation of lens wear on corneal curvature

IntroductionAccurate corneal measurements are crucial in corneal refractive surgery (CRS) to ensure successful outcomes. Soft contact lens (SCL) wear may result in changes to corneal curvature and structure. United States Food and Drug Administration (FDA) pre-operative guidelines recommend that prior to CRS, SCL wearers cease SCL wear for “at least two weeks before examination and treatment” [1]. Corneal curvature changes induced by SCL wear may take longer than two weeks to resolve.PurposeTo examine the effect of SCL wear on corneal curvature before and following two weeks SCL wear cessation. To explore the possible impact of different SCL materials and years of SCL wear.MethodsRetrospective data analysis, between a group of SCL wearers (SCL: n = 45); and a non-contact lens control group (NCL: n = 45). Corneal curvature parameters were measured using the Pentacam (Oculus, Germany), before and following two weeks cessation of SCL wear.ResultsNo significant differences in keratometry or Sagittal radius of curvature between SCL and NCL groups prior to or following SCL cessation. Tangential radius of curvature showed significant inferior steepening for the SCL group prior to SCL cessation (SCL vs. NCL; 7.77 ± 0.30 mm vs. 7.90 ± 0.30 mm; p = 0.04). Following two weeks cessation of SCL wear this appeared to have resolved.ConclusionsTwo weeks cessation of SCL wear appears sufficient for resolution of corneal curvature changes with modern SCL materials and years of SCL wear. However, further studies with longer lens deprivation periods are required to ensure stability for all SCL wearing patients.     

The role of corneo-scleral junction in soft contact lens fitting: Case report on nanophthalmos

BackgroundNanophthalmos is rare developmental ocular condition characterized by a small eye with short axial length, high hyperopia and high lens to eye volume ratio due to arrested development of eye ball as a result of scleral inelasticity.ObservationsA 33 year old woman who presented with a complaint of blurring of distance and near vision in both eyes since childhood came to LV Prasad Eye Institute on July 2017. Best corrected visual acuity was 20/60 using soft contact lens +23.50 diopters for the right and left eyes. Axial lengths of two eyes were markedly shortened along with steep corneal curvatures. Visante anterior segment ocular coherence tomography showed a steep (convex) corneo-scleral junction (CSJ) which might be the reason for ill-fitting with conventionally estimated soft contact lens (SCL) parameters. Finally, selection of the customized hydrogel soft contact lens base curve close to flatter corneal curvature and small diameter showed characteristics of optimal lens fit.ConclusionThe corneo-scleral junction profile plays significant role in soft contact lens fitting. An eye with a profile of convex CSJ would require a lens with steeper curvature compared to conventional measurements. Cases of nanophthalmos would require observation of the profile with the help of optical coherence tomography in addition to measurement of corneal curvature prior to fitting soft contact lenses.     

Cytotoxic and inflammatory effects of contact lens solutions on human corneal epithelial cells in vitro

Purpose

To ascertain the effect that four contact lens (CL) multipurpose solutions (MPS) have on the viability and release of pro-inflammatory cytokines from human corneal epithelial cells (HCEC).