Duration Of Contact Lens Wear Research Articles

Contact lenses as novel tear fluid sampling vehicles for total RNA isolation, precipitation, and amplification.

The tear fluid is a readily accessible, potential source for biomarkers of disease and could be used to monitor the ocular response to contact lens (CL) wear or ophthalmic pathologies treated by therapeutic CLs. However, the tear fluid remains largely unexplored as a biomarker source for RNA-based molecular analyses. Using a rabbit model, this study sought to determine whether RNA could be collected from commercial CLs and whether the duration of CL wear would impact RNA recovery. The results were referenced to standardized strips of filtered paper (e.g., Shirmer Strips) placed in the inferior fornix. By performing total RNA isolation, precipitation, and amplification with commercial kits and RT-PCR methods, CLs were found to have no significant differences in RNA concentration and purity compared to Schirmer Strips. The study also identified genes that could be used to normalize RNA levels between tear samples. Of the potential control genes or housekeeping genes, GAPDH was the most stable. This study, which to our knowledge has never been done before, provides a methodology for the detection of RNA and gene expression changes from tear fluid that could be used to monitor or study eye diseases.

TFOS lifestyle report: Effects of contact lenses on the ocular surface and adnexa

This presentation summarizes the evidence‐based findings of the Contact Lens Subcommittee of the recent Workshop of the Tear Film & Ocular Surface Society, entitled “A Lifestyle Epidemic: Ocular Surface Disease” (www.tearfilm.org).Several risk factors can increase the potential for complications associated with contact lens wear, such as ignoring appropriate contact lens care, disregarding an ocular or systemic disease (especially if associated with an unhealthy ocular surface), reduced clinical surveillance and the simultaneous use of excessive alcohol, tobacco, or recreational drugs. The recent pandemic has introduced novel challenges to the wear of contact lenses, including mask associated dry eye, discomfort and fatigue with digital devices, accidental exposure to hand sanitizers and a decreased duration of contact lens wear. Adverse environments for lens wearers, such as pollution, dust, smoke, and sport or work accidents determining ocular trauma, can represent challenges for the use of contact lens, though protective in some cases. To ensure the best outcomes for contact lens wearers in adverse situations, prescription choice should consider several factors, including night driving, sports, wear at high altitude, military application, and outer space environments.This presentation synthetises the lifestyle‐related choices made by both clinicians and contact lens wearers, and underlines that, if appropriately undertaken, these can positively impact contact lens wearers quality of life. A systematic review and meta‐analysis highlight the need to better understand the influence of lifestyle factors on contact lens dropout.

Correlation between long-term use of rigid gas permeable contact lenses and endothelial morphometric changes in keratoconus patients

PurposeThis study was conducted to evaluate the effects of long-term use of rigid gas-permeable (RGP) contact lenses on corneal endothelium in keratoconus (KC) patients using non-contact specular microscopy. In addition, the correlation between wearing duration of RGP lenses (years & hours /d) and endothelial morphometric changes in KC patients was performed. This may provide more useful data for clinical application of RGP contact lens. Study designThis study was a prospective, observational, comparative, hospital based, nonrandomized, cross-sectional, and quantitative study. Subjects and methodsThe study included 40 eyes of non-wearer contact lens KC patients (group 1) and 38 KC eyes with a long history of Rose K2 RGP contact lens wearing (group 2). The corneal endothelial morphology such as endothelial cell density (ECD); coefficient of variation of cell area (CV); percentage of hexagonal cells (HEX); and central corneal thickness (CCT) were evaluated in all patients using SP3000P Specular Microscope. ResultsThe study included 40 eyes of non-wearer contact lens KC patients (20 mild KC eyes and 20 moderate KC eyes) and 38 KC eyes with a long history of RGP contact lens wearing (18 mild KC eyes and 20 moderate KC eyes). The mean duration of RGP lenses wearing was 5.67 ± 3.481 years & 12.11 ± 2.698 h/d in mild KC eyes and 7.15 ± 5.294 years &13.65 ± 2.889 h/d in moderate KC eyes. Wearing duration in hours in mild KC eyes showed a significant moderate negative correlation with ECD (r = −0.529, p = 0.024) and a moderate positive correlation with CV (r = 0.565, p = 0.015). In addition, wearing duration in years in moderate KC eyes showed a significant moderate negative correlation with ECD (r = −0.465, p = 0.039) and moderate positive correlation with CV (r = 0.627, p = 0.003). However, wearing duration in hours in moderate KC eyes showed a significant moderate negative correlation with HEX only (r = −0.490, p = 0.028). This study reported significant corneal thinning in contact lens wearer KC eyes in contrast to non-wearer KC eyes. ConclusionThis study documented a significant correlation between a long-term use of Rose K2 RGP using the three-point touch and corneal endothelial morphometric changes in KC patients. In addition, the current study confirmed a significant corneal thinning in RGP contact lens wearer compared to non-contact lens wearer KC patients. Further studies are recommended to evaluate the association between different RGP lens materials with different oxygen permeability transmissibility; different lens design types; different fitting methods; the duration of contact lens wear and the endothelial morphometric changes in KC patients.

Evaluation of Corneal Densitometry and Endothelial Layer in Soft Contact Lens Users.

Soft contact lens wear may lead to physiological changes in the cornea. Corneal densitometry is a new software tool that may detect these physiological changes by monitoring their effects on corneal transparency. This study aimed to assess corneal densitometry values and corneal endothelium in patients using soft contact lenses. The study included 36 eyes of 36 subjects with soft contact lens use (group 1) and 36 eyes of 36 healthy control subjects (group 2). Anterior segment parameters and corneal densitometry of all subjects were evaluated using Scheimpflug corneal topography (Pentacam; Oculus Inc., Wetzlar, Germany). A total corneal area of 12 mm was divided into four annular zones (0 to 2, 2 to 6, 6 to 10, and 10 to 12 mm) and into three regions as anterior, central, and posterior for densitometry examination. Cell density, cell distribution, and cell morphology (quadrangular, pentagonal, hexagonal, and other cell percentages) of the endothelial layer were examined in both groups using specular microscopy (Nidek CEM 530; Nidek Co., Gamagori, Aichi, Japan). In group 1, the mean duration of contact lens wear was 4.45 ± 2.15 years. The anterior segment parameters were not significantly different between the two groups (P > .05). The anterior 0- to 2- and 2- to 6-mm corneal densitometry values were significantly higher in group 1 compared with group 2 (23.2 ± 4.7 for group 1 and 17.3 ± 5.6 for group 2 [P = .03]; 22.4 ± 6.4 for group 1 and 17.8 ± 1.4 for group 2 [P = .03], respectively). There were no significant differences between the groups for corneal densitometry values between 6 and 12 mm, or for cell density, cell distribution, and cell morphology (P > .05). Although the cornea remains transparent in soft contact lens wearers, corneal densitometry may increase in the 0- to 6-mm annular zone of the anterior region.

Evaluated Conjunctival Blood Flow Velocity in Daily Contact Lens Wearers.

This study examined conjunctival microvasculature development in long-term habitual contact lens (HCL) wearers after a night of sleep. Twenty HCL wearers (15 women and 5 men, aged 28.6±6.9 years, mean age±standard deviation) who had worn contact lenses on a daily basis for at least 3 years and 40 noncontact lens (NCL) wearers (23 women and 17 men, aged 36.5±6.6 years, mean age±standard deviation) participated in the study. A functional slitlamp biomicroscopy imaging system was used to image the temporal bulbar conjunctiva. Imaging was performed in the morning while the contact lens wearers were not wearing their lenses after a night of sleep. The conjunctival vessel diameters, blood flow velocities, and flow rates were measured. In addition, fractal analyses were performed to obtain the vessel network density (Dbox) and complexity (D0). The average blood flow velocity in HCL wearers after a night of sleep was 0.59±0.19 mm/s, which was significantly higher than that in NCL wearers (0.48±0.17 mm/s, P<0.05). The microvessel network density and complexity levels (Dbox=1.64±0.05 and D0=1.71±0.05, respectively) in the HCL wearers were significantly higher than those in NCL wearers (Dbox=1.61±0.05 and D0=1.69±0.04, both P<0.05). The blood flow velocity was positively correlated with the duration of contact lens wear (r=0.46, P<0.05) and with the daily number of lens-wearing hours (r=0.49, P<0.05) in HCL wearers. This study identified microvascular alterations in the conjunctiva in response to daily contact lens wear after a night of sleep in long-term daily contact lens wearers. The unrecovered changes may indicate that para-inflammation occurs on ocular surfaces because of contact lens wear and that overnight sleeping with no lenses may not sufficiently restore the ocular surface to an intact state.

Influence of long-term using of soft contact lenses on indicators of oxidative-reducing potential of glutathione, peroxidation of lipids, and the state of cell membranes and cellular structures of the epithelium of the cornea

Contact lenses are increasingly used worldwide for correcting refraction disorders. However, contact lenses can destroy a biochemical composition of the tear. Purpose — to determine the effect of long-term use of silicone-hydrogel contact lenses on the parameters of the oxidation-reduction potential of glutathione, lipid peroxidation and the stability of cell membranes and subcellular structures of the cornea of the epithelium by identifying marker enzymes in a tear. We determined the activity of lactate dehydrogenase, glucose-6-phosphate dehydrogenase, acid phosphatase, succinatе dehydrogenase, glutathione (recovered and oxidized forms) and products of lipid peroxidation (malonic dialdehyde, diene conjugates) in tears of patients divided into two groups. Study group comprised 72 people — mild and moderate myopia patients continuously wearing soft contact lenses. Control group consisted of 33 people — mild and moderate myopia patients, spectacles wearers. We revealed a significant increase in the activity of lactate dehydrogenase and glucose-6-phosphate dehydrogenase by &gt;33% and &gt;26%, respectively, as well as a significant increase in the activity of acid phosphatase by &gt;21% and of succinatе dehydrogenase by &gt;18% in the tudy group patients comparing to controls. The study of the level of products of lipid peroxidation in the tear fluid of the main group showed a significant accumulation of them, as well as a violation of the glutathione balance in comparison with the control group. The dependence of biochemical changes in the composition of the tear on the duration of contact lens wear has been revealed. Therefore, with prolonged wearing of MKL, prooxidant-antioxidant equilibrium in the tissues of the eye surface, in particular in the cornea, is violated, activation of free radical processes and reduction of antioxidant reserves occur, which leads to destruction of cellular and subcellular membranes. We assume that the medical correction of these pathological changes will help prevent the development of severe complications of contact correction.

Contact lens trends over three decades in a hospital‐based practice in India

BackgroundContact lens fittings in a hospital‐based practice are different from those in private practices because of specialised conditions. Few studies have been published on material preferences of such wearers, especially in long‐term wearers. The aim of this study is to document contact lens prescribing trends in a hospital‐based practice among long‐term lens wearers and to identify their demographic profile.MethodsSubjects reporting to a contact lens clinic of a tertiary eye‐care centre in India from 1 January 2014 to 31 December 2014, with a minimum of five years of lens wear, were included in the study. Data were collected retrospectively from the electronic medical charts of these subjects.ResultsThree hundred and sixty subjects were included in the study. The average duration of contact lens wear among the subjects was 9 ± 5 years (range: 5–35 years). The average age of the subjects was 31.38 ± 11.75 years (age range: 5–78 years). Hydrogel material and soft spherical type were preferred by most of the soft lens wearers (53 per cent). Eighty per cent of subjects followed hand hygiene and cleaning regimen practices.ConclusionThe preference for monthly replacement lenses and silicone hydrogel material increased over the years. Regular after‐care consultations could enforce the need for compliance with hand hygiene and cleaning regimens among lens wearers.

Corneal confocal microscopy and dry eye findings in contact lens discomfort patients

To evaluate the corneal confocal microscopy and dry eye findings in patients with contact lens discomfort. The study included 3 groups of participants: Contact lens wearers using silicone hydrogel soft contact lenses who are symptomatic (CLD, n=15) or asymptomatic (ACL, n=11) and non-wearers as controls (n=14). Duration of contact lens wear, Ocular Surface Disease Index (OSDI) questionnaire responses, fluorescein tear break-uptime (FBUT), and corneal confocal microscopy findings were recorded. Mean age was 25.7±8.2 years and male/female ratio was 7/33. Demographic findings were similar regarding the groups. CLD patients had a longer lens use history than ACL (median 5 vs 2 years, p<0.001). OSDI scores were higher in CLD group than ACL or controls (p<0.001, p=0.002). FBUT was significantly lowest in CLD group, compared to controls and ACL (p<0.001, p=0.039). FBUT was also lower in ACL patients compared to controls (p=0.036). There was no difference between basal epithelium cell counts between all 3 groups. Anterior stromal activated keratocyte numbers were similar between contact lens using groups but was lower in controls (p=0.005). However, dendritiform cells in the sub-basal nerve layer were higher in CLD group compared to controls but similar to ACL (p<0.001, p=0.058). Graded sub-basal nerve tortuosity was more prominent in CLD group than the ACL (p=0.014). Patients with CLD had been wearing contact lenses for longer than those without symptoms. OSDI and FBUT scores were worse in CLD patients. In contact lens discomfort patients, there were increased dendritiform cells, indicating intensified inflammatory status of the cornea.

Focal limbal stem cell deficiency associated with soft contact lens wear

ObjectiveThe aim of this study is to summarize the clinical characteristics of patients with contact lens–associated focal limbal stem cell deficiency (FLSCD) from a tertiary corneal referral centre. DesignRetrospective, observational case series in a tertiary care centre. MethodsPatients with contact lens–associated FLCSD were identified in our database. Clinical data were retrieved by chart review. A questionnaire asking for contact lens brand, type, cleaning solution, and duration of contact lens wear was sent to the patients with telephone follow-up. Clinical features and recovery time were identified. ResultsTwenty-seven eyes of 17 patients were identified with superior corneal whorl-like patches of opaque epithelium, sometimes accompanied by neovascularization. Of the patients, 17/17 used soft contact lenses, with a mean wearing duration of 11.4 hours per day. Patients had been wearing lenses for an average of 18.1 years. Silicone hydrogel lenses were noted in 12/17 cases. LSCD was superior in all 27 eyes, and all of them improved with contact lens wear cessation, preservative-free topical steroids, and preservative-free artificial tears. Visual acuity improved from 20/28 to 20/22 (p < 0.001). ConclusionsContact lens–associated FLSCD typically presents in the superior cornea with whorl-like epithelial opacities advancing from the limbus. Conservative medical treatment is available and shows a high success rate after a slow recovery.

The Use of Bandage Contact Lenses in Adenoviral Keratoconjunctivitis.

To evaluate the safety and efficacy of the use of the bandage contact lenses (BCLs) in adenoviral keratoconjunctivitis-related ocular surface problems. Fifteen eyes of 15 consecutive patients presenting at the Ankara University Medical Center, Cornea and Contact Lens Service, and requiring BCL use for adenoviral keratoconjunctivitis-related ocular surface problems were enrolled. Visual acuity, slitlamp examination findings, indication and duration of the BCL use, the total follow-up, and any adjuvant medication were recorded. All patients were followed regarding the success of treatment and adverse effects associated with BCL use. The average age at the time of presentation was 26.8±15.5 years. The major reasons for BCL use included epithelial defect (7 eyes), filamentous keratopathy (5 eyes), epithelial edema (1 eyes), and filamentous keratopathy together with epithelial defect (2 eyes). After the first appearance of conjunctivitis symptoms, the mean time to BCL application was 9.0±3.9 days. The mean duration of contact lens wear was 9.9±6.5 days, and the mean follow-up was 26.4±15.8 days. Preservative-free artificial tears and topical antibiotics were used in all cases. Besides, topical ganciclovir 0.15% gel (8 eyes), topical 0.4% povidone-iodine solution (9 eyes), and topical steroids (11 eyes) were used in various combinations. At the end of the follow-up period, the mean visual acuity improved from 0.23±0.32 logMAR units (∼0.6 Snellen line) to 0.0l±0.04 logMAR units (∼1.0 Snellen line) (P=0.042). No sight-threatening complication related to contact lens wear was encountered. Adjuvant use of BCLs seems to be safe and effective in the treatment of adenoviral keratoconjunctivitis-related ocular surface problems. Close follow-up and prophylactic use of topical antibiotics are rationalistic for prevention of secondary infections.

Impact of duration of contact lens wear on the structure and function of the meibomian glands.

To investigate the effects of the duration of contact lens (CL) wear on the meibomian glands (MGs), eyelid and tear film. This was a cross-sectional study of CL wearers and non-wearers (NWs) aged between 18 and 35 years. The sample comprised of: (i) Three groups of CL wearers of different duration profiles (short, moderate and long experience of CL wear); (ii) a group of previous CL wearers (PWs) who had ceased wear for at least 6 months prior to the present study; (iii) healthy non-wearers as a control group. Study procedures were conducted in the order from least invasive to most invasive as follows: symptom assessment, lipid assessment, non-invasive break-up time, tear meniscus area, tear osmolarity and evaporation, Phenol red thread, MG expressibility, ocular surface and eyelid assessments, meibography, Marx line and lid wiper assessment using lissamine green. For statistical comparison of continuous data, one-way analysis of variance was used with Bonferroni post-hoc correction, where appropriate. Kruskal-Wallis test and Pearson Chi-Square respectively were used for ordinal and categorical variables. A total of 100 participants (49 males and 51 females; mean age ± SD: 25.4 ± 4.1) were enrolled across the five groups, such that each was composed of 20 age/sex matched individuals. Significant differences between the study groups were found for MG expressibility (p < 0.001), number of plugged orifices (p = 0.001), number of expressed orifices (p < 0.001), MG dropout (p = 0.001), Marx line score (p < 0.001), palpebral redness (p = 0.003), and roughness (p = 0.002), non-invasive break-up time (p < 0.001), Phenol red thread (p = 0.005), and tear meniscus area (p = 0.029). For all these variables, the NW group was statistically different from all other groups. Duration of wear was not a significant factor, except for Marx line score which was different in PWs compared to those with longer experience of CL wear (p = 0.03) CONCLUSION: Alterations to MG morphology and function accompany contact lens wear. Although these changes onset during the first 2 years of wear, prolonged CL exposure beyond this point does not appear to be associated with further modification. Cessation of wear for at up to 6 months does not lead to resolution.

KeraSoft 3 contact lenses in corneal ectasia.

To evaluate the safety, efficacy, and on-eye performance of KeraSoft 3 contact lenses (UltraVision) in ectatic corneal diseases. The charts of patients who were fit with KeraSoft 3 were reviewed. The reason for KeraSoft 3 lens fit, the number of trial lenses required for ideal fit, centration, movement, and stabilization of the contact lens, uncorrected, spectacle-corrected, and contact lens-corrected visual acuities, slitlamp biomicroscopy findings, patient comfort, and daily duration of contact lens wear were evaluated. Seventy eyes of 40 patients were fit with the KeraSoft 3 lens. Indications included rigid gas permeable (RGP) lens intolerance in 41 eyes of 24 patients (58.5%), patients' desire to use soft contact lenses in 26 eyes of 14 patients (37.1%), and proud nebula in 3 eyes of 2 patients (4.4%). The number of trial lenses required for ideal fit was 1.2±0.4 lenses. Eleven patients (20 eyes, 29%) never purchased the contact lens, 15 patients (26 eyes, 37%) discontinued after purchasing, and 14 patients (24 eyes, 34%) continued successfully wearing their lenses. In the latter group, the visual acuity improved significantly (P<0.05) and no adverse events were encountered during the mean follow-up period of 10.0±9.8 months. At the last follow-up examination, patients rated comfort and visual acuity with their contact lenses as "very good" to "excellent," with a desire to continue wearing them. In refractive correction of corneal ectasia, KeraSoft 3 contact lenses seem to be a good alternative to RGP lenses before more sophisticated lenses such as hybrid or scleral lenses are tried.

The Risk of Microbial Keratitis With Overnight Corneal Reshaping Lenses

To estimate the incidence of microbial keratitis (MK) associated with overnight corneal reshaping contact lenses and to compare rates in children and adults. A retrospective study of randomly selected practitioners, stratified by order volume and lens company, was conducted. Practitioners were invited to participate and those agreeing were asked to provide deidentified patient information for up to 50 lens orders and to complete a comprehensive event form for any of these patients who have attended an unscheduled visit for a painful red eye. Duration of contact lens wear was calculated from the original fitting date or January 2005 (whichever was later) to when the patient was last seen by the practitioner wearing the lenses on a regular basis. Cases of MK were classified by majority decision of a 5-member expert panel. For the 191 practitioners who could be contacted, 119 (62%) agreed to participate. Subsequently, 11 withdrew, 22 did not respond, and 86 (43%) returned completed forms corresponding to 2202 lens orders and 1494 patients. Limiting the sample to those patients with at least 3 months of documented contact lens wear since 2005 resulted in a sample of 1317 patients; 640 adults (49%) and 677 children (51%) representing 2599 patient-years of wear (adults = 1164; children = 1435). Eight events of corneal infiltrates associated with a painful red eye were reported (six in children and two in adults). Two were classified as MK. Both occurred in children but neither resulted in a loss of visual acuity. The overall estimated incidence of MK is 7.7 per 10,000 years of wear (95% confidence interval [CI] = 0.9 to 27.8). For children, the estimated incidence of MK is 13.9 per 10,000 patient-years (95% CI = 1.7 to 50.4). For adults, the estimated incidence of MK is 0 per 10,000 patient-years (95% CI = 0 to 31.7). The risk of MK with overnight corneal reshaping contact lenses is similar to that with other overnight modalities. The fact that the CIs for the rates estimated overlap should not be interpreted as evidence of no difference. True differences fewer than 50 cases per 10,000 patient-years were beyond the study's power of detection.

Evaluation of Contact Lens–Induced Changes in Keratoconic Corneas Using In Vivo Confocal Microscopy

To quantitatively analyze laser scanning in vivo confocal microscopy (IVCM) images of all corneal layers in contact lens-wearing and noncontact lens-wearing keratoconus patients. The study population included rigid gas permeable (RGP) contact lens-wearing keratoconus patients (group 1; N = 29), keratoconus patients who did not wear contact lenses (group 2; N = 30), and subjects who neither had keratoconus nor wore contact lenses (group 3; N = 30), with groups 2 and 3 matched to group 1 by age and sex. The central cornea was examined with IVCM in all subjects. The mean duration of contact lens wear was 5.50 ± 3.68 years (range, 2-15 years). Eyes with keratoconus showed significantly lower basal epithelial cell and anterior and posterior stromal keratocyte densities, as well as subbasal nerve fiber density, nerve branch density, and nerve fiber length compared with healthy control subjects. Furthermore, compared with group 2, group 1 had significantly lower basal epithelial cell density (4920 ± 476 cells/mm(2) vs. 4503 ± 461 cells/mm(2), P = 0.001) and anterior stromal keratocyte density (561 ± 91 cells/mm(2) vs. 464 ± 55 cells/mm(2), P < 0.001), but there was no significant difference for posterior stromal keratocyte density (P = 0.808), endothelial cell density (P = 0.699), or subbasal nerve fiber density (P = 0.142), nerve branch density (P = 0.614), and nerve fiber length (P = 0.850). Significant corneal microstructural abnormalities were observed in eyes with keratoconus. RGP contact lens wear was associated with a further reduction in the basal epithelial cell and anterior stromal keratocyte densities, but with no effect on posterior stromal keratocyte density, endothelial cell density, or corneal nerve morphology.

Continuous Wear of Hydrogel Contact Lenses for Therapeutic Use

Purpose: To investigate the efficacy and complications of continuous wear of etafilcon A for therapeutic use. Materials and Methods: The subjects were 228 eyes of 219 outpatients prescribed contact lens (CL) for one week of continuous therapeutic wear during 10 years. The reason for prescription of CLs, the primary disease, the duration of CL wear and the complications were assessed retrospectively. Results: The predominant reason for prescription of CLs was relief of pain or a foreign-body sensation (62.3%) and protection of the corneal epithelium (20.6%). The primary disease was post-penetrating keratoplasty (36.8%), followed by corneal epithelial erosion (14.5%), post-lamellar keratoplasty (14.0%) and bullous keratopathy (12.2%). The average duration of wearing single lens was 6.5 ± 3.2 days. The average duration of wearing CLs in total was 9.2 ± 10.7 months. The most frequent problem associated with continuous wear of CLs was their dropping out of CLs (12.3%). The complications associated with CLs included conjunctivitis with papillary hyperplasia, corneal erosion and superficial punctate keratitis, but corneal ulcer and corneal infiltrates were not found. Conclusion: Serious complications were not shown changing the lenses every week to keep to the prescribed time limit for continuous therapeutic wear, even if corneal epithelial barrier function is impaired.

In vivo confocal microscopy: corneal changes of hydrogel contact lens wearers

To evaluate the corneal findings in hydrogel contact lens wearers by in vivo confocal scanning microscopy. One hundred and forty-two eyes of 71 myopic contact lens wearers (group 1) and 142 eyes of 71 non-contact lens wearers (group 2), whose age, gender and refractive error matched, were enrolled in order to detect the corneal changes by in vivo confocal microscopy through the central cornea. The average age was 25.5±5.7 (16-52) and 25.6±5.6 (17-49) in groups 1 and 2, respectively. The mean duration of contact lens wear was 43.9±15.3 (6-240) months. Anterior keratocyte density was 667.5±128.3 cells/mm(2) in group 1 and 821.4±136.7 cells/mm(2) in group 2 (P=0.001). Posterior keratocyte densities of groups 1 and 2 were 540.2±87.6 cells/mm(2) and 628.2±72.4 cells/mm(2), respectively (P<0.001). Endothelial cellular density was 2611.2±298.4 cells/mm(2) in group 1 and 2643±218.2 cells/mm(2) in group 2 (P=0.52). Ratio of polymegethism was 44.6±8.8% in group 1 and 31.3±4.7% in group 2 (P<0.001). Epithelial cellular enlargement was observed in eyes wearing contact lenses with a mean Dk/t ratio of 26.5×10(-9)±5.9 (8.9-32×10(-9)). Stromal microdots occurred with contact lenses with a mean Dk/t ratio of 13.2×10(-9)±17.5×10(-9) (8.9-20×10(-9)). In vivo examination of the cornea with confocal microscopy revealed a number of changes. These changes can be attributed both to the mechanical and the hypoxic effects of soft contact lenses. In soft contact lenses with a high Dk/t ratio, these changes would be less frequent.

Contact Lens Wear and the Development of Squamous Metaplasia of the Surface Cells of the Conjunctiva

To review the reported effects of contact lens wear on the surface epithelial cells of the human conjunctiva as assessed by conjunctival impression cytology (CIC). A literature search was undertaken to identify reports on the conjunctival health after contact lens wear, principally as assessed using CIC. Of 26 reports identified, 22 examined the bulbar conjunctiva, and 2 examined the tarsal conjunctiva. Just 16 reports provided data from which mean squamous metaplasia grades could be calculated, with the overall grade being just 0.7 on a 0 to 3 scale. Only 13 of these studies provided unambiguous data on the duration of contact lens wear, and only an apparent trend was evident in that grades of squamous metaplasia increased over early years of lens wear. Such a trend was not statistically significant either up to 6 years of average lens wear (P>0.05) or over all studies (P>0.5). The estimated variability in squamous metaplasia was substantially greater when low grades were reported, an observation that either reflects the heterogeneity in the cell response or highlights the difficulty in assigning low grades to cell samples. Based on subjective grading, CIC studies reveal no clearly definable relationship between the duration of contact lens wear and the extent of development of conjunctival squamous metaplasia. Logically, therefore, objective methods to assess squamous metaplasia are needed. Various options for quantitative CIC are discussed, including the use of in vivo confocal microscopy.

Not only hard contact lens wear but also soft contact lens wear may be associated with blepharoptosis

Objective The authors attempt to establish an association between prolonged hard and soft contact lens wear and ptosis. Design Single-center retrospective consecutive series. Participants All patients between 18 and 50 years of age who were diagnosed with unilateral or bilateral ptosis between January 2002 and December 2005 (35 patients). Methods In a retrospective consecutive series, we included all patients between 18 and 50 years of age, with unilateral or bilateral ptosis between January 2002 and December 2005. Patients with congenital ptosis, ophthalmic surgery or disease, trauma, giant papillary conjunctivitis, unknown duration of contact lens wear, or muscular or neurologic disorders were excluded. We compared this study group to a Dutch reference population (the total underlying population from which the ptosis cases derive). Results The group included 35 patients: 20 (57%) (ages 18 to 50 years, average 37 years) had been wearing hard contact lenses for, on average, 17.6 years (range 6 to 27 years); 9 (26%) (ages 18 to 45 years, average 30 years) had been wearing soft contact lenses for, on average, 9 years (range 1.5 to 20 years); and 6 (17%) (ages 23 to 39 years, average 33 years) had no history of contact lens wear. The odds ratio for soft contact lenses was 14.7 (4.2 to 50.7; CI = 95) and for hard contact lenses 97.8 (22.5 to 424). Conclusions This study suggests that not only hard contact lens wear but also soft contact lens wear may be associated with ptosis.

In Vivo Confocal Microscopy of Meibomian Glands in Contact Lens Wearers

To evaluate by in vivo laser scanning confocal microscopy (LSCM) the morphologic changes in the meibomian glands (MGs) and the status of periglandular inflammation in contact lens wearers (CLWs) and to investigate the correlations between clinical and confocal findings. Twenty CLWs and 20 age- and sex-matched control subjects were consecutively enrolled. Each participant completed an Ocular Surface Disease Index questionnaire and underwent a full eye examination, including tear film break-up time, fluorescein and lissamine green staining, and Schirmer test. LSCM of the MGs were performed to determine the cell density of the mucocutaneous junction epithelium, acinar unit density and diameter, glandular orifice diameters, meibum secretion reflectivity, and inhomogeneous appearance of the glandular interstice and acinar wall. All clinical parameters showed statistically significant differences between groups (P < 0.01, Mann-Whitney U test) except the Schirmer test. Confocal data (Mann-Whitney U test) showed significantly decreased basal epithelial cell density (P < 0.01), lower acinar unit diameters (P < 0.05), higher glandular orifice diameters (P < 0.05), greater secretion reflectivity (P < 0.01), and greater inhomogeneity of the periglandular interstices (P < 0.05) in CLWs compared with controls. The duration of contact lens wear was correlated with the acinar unit diameters (P < 0.05, Spearman). Morphologic changes in the MGs shown by LSCM were interpreted as signs of MG dropout, duct obstruction, and glandular inflammation. A comprehensive LSCM evaluation of the ocular surface in CLWs could better clarify the role of MG dropout and eyelid margin inflammation on the pathogenesis of CL-induced dry eye.

Contact lens wear and the goblet cells of the human conjunctiva—A review

To review the reported effects of contact lens wear on the goblet cells of the human conjunctiva. A literature search was undertaken to identify reports on the conjunctival health after contact lens wear, principally as assessed using the conjunctival impression cytology (CIC) technique in which cells are examined ex vivo, after fixation and staining. Details of technique, data on duration of contact lens wear and then CIC outcome in terms of goblet cell density (GCD) were extracted. Of 24 reports identified, 22 examined the bulbar conjunctiva and 2 examined the tarsal conjunctiva. A decrease in GCD was considered, directly or indirectly, to be a consequence of contact lens wear in 18 of the studies, but there was no obvious overall relationship between duration of lens wear and the GCD changes. Conversely, four reports indicated an increase in GCD or goblet cell-related mucins. Two reports concluded that there was no change in goblet cells or their mucin, a result however that is consistent with a recent conclusion that no statistically significant change in GCD was detectable in contact lens wearers assessed by in vivo imaging of the human conjunctiva by confocal microscopy. The majority of published studies have concluded that contact lens wear results in a decrease in goblet cells in the conjunctiva. While there are reports that draw a very different conclusion, it should be noted that there has been limited consistency in technique or the method of reporting the results across the various studies.