Long-term Wearers Research Articles

A snap-shot of orthokeratology lens rinsing habits: An online survey in a major eye hospital in Shanghai

PurposeA hospital-based survey to explore lens rinsing habits of orthokeratology (ortho-k) patients, including the solution used for rinsing. MethodsAn anonymous survey, via an online questionnaire, was administered to ortho-k lens wearers or their parents when they attended Fudan University Eye and ENT Hospital for routine follow-up visits. Three major issues were investigated: basic demographics, lens rinsing solution used, and specific rinsing habits. Relationships between demographics and rinsing solution used and rinsing behaviours were explored. ResultsOf the total of 541 online questionnaires delivered, 296 were completed and returned. The respondents were the person responsible for lens care, either the ortho-k users themselves, or their parents. The median age of the lens wearers was 12.0 years (range: 8–22 years), and the median period of ortho-k lens wear was 18.0 months (range: 1–109 months). The most common rinsing solutions reported were a particular brand of multidose preserved saline (28.4%), cooled boiled water (23.3%), and non-preserved multidose saline (16.2%). Overall, the main reason for choice of rinsing solution was recommendation of eye care practitioners (90.2%). The respondents with a longer lens wear history tended to use commercially available bottled water, drinking water, or cooled boiled water rather than non-preserved saline (unidose or multidose) (p ≤ 0.009) and were more likely to use the rinsing solution to soak their lenses (p = 0.009). Lens wearers who rinsed the lenses themselves tended to use tap water compared to those whose lenses were handled by parents (p = 0.040). ConclusionInappropriate choice and usage of rinsing solution appeared to be a common issue among ortho-k lens wearers in Shanghai, China. The problem was more pronounced in long-term wearers and in those who performed rinsing themselves.

Candida Colonization on the Surface of Contact Lenses in Long-Term Wearers and Boston Type 1 Keratoprosthesis Patients Presenting as White Mulberry-Shaped Deposits.

To report Candida colonies on the surface of the contact lens in long-term contact lens wearers and patients with Boston type 1 keratoprosthesis (KPro I). A retrospective study was performed based on analyzing cultures from bandage contact lenses with small whitish mulberry-shaped deposits on their surface. Eight samples (from seven patients) were positive for Candida. Seven of the eight were positive for Candida parapsilosis. The whitish deposits on contact lenses are often Candida colonies that colonize the surface but do not cause an active infection in the eye. C. parapsilosis is well-known for colonizing prosthetic devices. We underline the importance of including Candida species in the differential diagnosis of lens deposits, especially in susceptible patients such as keratoprosthesis carriers.

MANAGEMENT OF HYPER-MOBILE TISSUE WITH A MODIFIED COMBINE TECHNIQUE OF ZAFRULLA AND HOBKRIK

When in partially edentulous patient hyperplastic tissue replaces the alveolar bone, a flabby ridge develops which is often seen in long-term denture wearers. Flabby ridge provide poor retention for the denture fabrication if not recoded properly. A careful consideration and application of Zafrulla and Hobkrik technique of complete denture construction helps practitioner to over cone such conditions easily. This article describes procedure performed for flabby ridge patient and demonstrates Zafrulla and Hobkrik combination impression technique.

Tear hypoxia-inducible factor-1α expression, lactate dehydrogenase, and malate dehydrogenase activity changes in soft contact lens wear

BACKGROUND Soft contact lens (SCL) wear can lead to a corneal hypoxia. However, there is a lack of studies looking for corneal hypoxia biomarkers in tear. This study aimed to investigate corneal hypoxia among SCL wearers based on hypoxia-inducible factor-1α (HIF-1α) expression, tear lactate dehydrogenase (LDH), and malate dehydrogenase (MDH) activities.
 METHODS A nonrandomized clinical trial was conducted on two groups. SCLs were prescribed for 2 months to a group of new wearers. Meanwhile, SCL wear was discontinued for 1 month in a group of long-term wearers. Tear samples were then collected on days 1, 7, 14, 28, and 56 after treatment. Repeated-measures analysis of variance and Friedman’s test with post-hoc statistical analysis were used to evaluate biomolecular changes (HIF-1α concentration, LDH, and MDH activities) in both groups.
 RESULTS A total of 14 subjects (28 eyes) were enrolled in each group. In new wearers, there was a significant decrease in MDH level (p = 0.010) and no effect on HIF-1α level. In long-term wearers, HIF-1α and LDH levels tended to decrease (p = 0.054). A significant decrease on MDH level was noted on days 7 (p = 0.003), 14 (p = 0.026), and 28 (p<0.010). Long-term wearers had a higher LDH baseline level than new wearers (p = 0.04).
 CONCLUSIONS Corneal hypoxia was not proven after 2 months of SCL wear using biomarkers. However, LDH and MDH activities in tears were found to be decline after SCL discontinuation.

Long-term dental and skeletal effects of mandibular advancement devices in adults with obstructive sleep apnoea: A systematic review

This systematic review aimed to clarify whether there are any significant long-term sequelae to wearing mandibular advancement devices focusing on dental and skeletal effects in adults with OSA. Databases, including PubMed, Medline, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and SAGE Journals. Hand searches and grey literature were also used. A piloted data collection form was used to extract the appropriate data. Twenty-three reports of 19 studies were included. Five had serious risk of bias while 18 had moderate risk of bias. Meta-analysis revealed a significant change in overbite and overjet. I-squared analysis showed a high level of statistical heterogeneity. A moderate correlation was found between wear time and amount of change. Mandibular advancement devices will cause a small but statistically significant change in the dentition of long-term wearers. Skeletal changes are generally secondary to dental changes.

Management of flabby ridge case: An arduous task in undergraduate practice

A fibrous or flabby ridge is a superficial area of mobile soft tissue affecting the maxillary or mandibular alveolar ridges. It can develop when hyperplastic soft tissue replaces the alveolar bone and is a common finding particularly in the upper anterior region of long-term denture wearers. Masticatory forces can displace this mobile denture-bearing tissue, leading to altered denture positioning and loss of peripheral seal. Unless managed appropriately, such “flabby ridges” adversely affect the support, retention, and stability of complete dentures. Many impression techniques have been proposed to help overcome this difficulty. This paper presents case report for prosthodontic rehabilitation of a patient with flabby ridge with McCord and Ahmad impression technique.

Differences of salivary cortisol levels between long-term and short-term wearers of dento-maxillary prosthesis due to head and neck cancer resection

PurposeThe purpose of this study was to use cortisol awakening response (CAR) to investigate the differences in daily life stress experienced by individuals wearing either a long-term (LT) or a short-term (ST) dento-maxillary prosthesis following head and neck cancer (HNC) resection. Also we used the University of Washington Quality of Life (UW-QOL) version 4 questionnaire to evaluate the differences in quality of life (QOL) scores between ST and LT wearers of a dento-maxillary prosthesis. MethodsSalivary samples were collected from 11 LT and 10 ST prosthesis wearers on two consecutive days at two time points, immediately after waking up (T0) and 30min later (T30), by passive drool collection. Cortisol levels were measured using a high sensitivity salivary cortisol enzyme immunoassay kit (Salimetrics, LLC, State College, PA, USA) and CAR (the differences between the cortisol levels at T0 and T30) was compared between LT and ST prosthesis wearers. In addition, both the groups completed the UW-QOL questionnaire and the scores were compared. ResultsA significant difference was observed in CAR between the two groups. CAR of the ST prosthesis wearers was significantly lower compared with that of the LT prosthesis wearers; moreover, the ST prosthesis wearers revealed significantly lower total UW-QOL scores and there were significant differences in appearance, activity, recreation, speech, and anxiety. ConclusionWithin the limitations of this study, the findings suggest that individuals wearing ST dento-maxillary prostheses following HNC resection experience some sort of daily life stress and complicated socio-demographic factors may influence their QOL.

Adaptive gait changes in long‐term wearers of contact lens monovision correction

The aim of the present study was to determine adaptive gait changes in long-term wearers of monovision correction contact lenses by comparing gait parameters when wearing monovision correction to those observed when wearing binocular distance correction contact lenses. Gait and toe clearance parameters were measured in eleven participants (53.5 +/- 4.6 years, median monovision wearing time 5 years) as they repeatedly walked up to and onto a raised surface with either monovision or distance correction. Compared to distance correction, monovision resulted in a large reduction in stereoacuity from 17'' to 87'', a slower walking velocity (p = 0.001), a reduced horizontal toe clearance of the step edge (p = 0.035) and, for trials when monovision correction occurred first, a 33% greater variability in vertical toe clearance (p = 0.021). Variability in some gait data was large due to certain study design features and learning effects. A slower walking velocity with monovision correction suggests participants became more cautious, likely as a result of the significantly reduced stereoacuity. The decreased horizontal toe clearance and increased vertical toe clearance variability suggests that monovision correction may cause a greater likelihood of hitting step edges and tripping during everyday gait. Recommended study design features are suggested for future adaptive gait studies to increase the precision of the data and to attempt to minimize the effects of learning from somatosensory feedback.

Objective and Subjective Responses in Patients Refitted to Daily-Wear Silicone Hydrogel Contact Lenses

Silicone hydrogel (SiH) lenses offer many physiological advantages for daily wear (DW) in addition to the continuous-wear modality for which they were originally developed. The purpose of this study was to investigate the clinical performance and physiological responses in a group of successful long-term wearers of conventional hydrogel lenses when refitted with DW SiH contact lenses. Eighty-seven successful soft lens wearers (8.4+/-4.7 years of prior lens wear) participated in this study. Bulbar and limbal hyperemia were subjectively graded and digitally photographed for subsequent masked objective evaluation. Subjective symptoms were scored using visual analog scales. In addition, refractive error, corneal curvature, and corneal thickness were measured. All subjects were refitted with Focus Night & Day (lotrafilcon A) SiH lenses; however, to reduce the potential for bias, they were informed that they were being randomly assigned to wear either low oxygen permeability (Dk) lenses or high Dk SiH lenses and were "masked" as to their lens assignment. Subjects returned after 1 week, 1 month, and 2 months of DW, at which time all gradings, photographs, and measurements were repeated. End-of-day subjective symptoms were also graded periodically during the study. Ninety-three percent of subjects were successfully refitted. Both objective and subjective evaluations showed that bulbar and limbal hyperemia decreased significantly in all quadrants during the study (p<0.001), particularly for those subjects with greater baseline hyperemia (p<0.001). Subjects reported a concurrent reduction in end-of-day dryness and improved end-of-day comfort compared with their habitual lenses (p<0.001). No significant changes in refractive error, tarsal papillary response, corneal curvature, or corneal thickness were found during the study. Hyperemia in contact lens wearers may be attributed to a number of factors, including hypoxia. Refitting existing low Dk lens wearers with SiH lenses on a DW basis can result in a decrease in hyperemia, which may be significant for some subjects and also results in improvements in symptoms of dryness and discomfort.

Comparison of Corneal Thickness of Long-Term Contact Lens Wearers for Different Types of Contact Lenses

To compare the central corneal thickness (CCT) values of long-term wearers of different types of contact lenses with those of each other and a normal control group. Twenty-three healthy eyes with no history of contact lens wear were used for the control group. Forty-eight eyes were evaluated in four different groups according to the type of contact lens worn; each group comprised 12 eyes. Group 1 (SofLens 38) and group 2 (Contact Day 30) had worn daily-wear frequent-replacement soft contact lenses with a 38% and 55% water content, respectively, and they had worn their lenses for an average of 4.28 +/- 1.70 years and 3.71 +/- 1.11 years, respectively. Group 3 (Wöhlk A90) and group 4 (Conflex-air) had worn daily-wear rigid gas-permeable (RGP) contact lenses with a Dk/t value of 68 and 22, respectively, and they had worn their lenses for an average of 3.00 +/- 0.63 years and 3.25 +/- 1.17 years, respectively. CCT values in micrometers were measured by optical coherence tomography. When comparing the CCT between the control group and the contact lens groups, the CCT was significantly thinner in the group wearing Conflex-air RGP contact lenses with a low Dk/t value (P = 0.010). In comparing the CCT among the four contact lens groups, the CCT was significantly thinner in the group wearing SofLens 38 contact lenses with a water content of 38% than in the group wearing Contact Day 30 contact lenses with a water content of 55% (P = 0.004). There was also significant thinning in the group wearing Conflex-air RGP contact lenses versus the group wearing Contact Day 30 soft contact lenses (P = 0.0005). CCT was significantly thinner in patients wearing long-term low-Dk/t RGP contact lenses compared to no contact lens wear and soft contact lenses with a water content of 55%. CCT was also decreased significantly in long-term soft contact lens wear with a water content of 38% compared to 55%.

Predicting time to refractive stability after discontinuation of rigid contact lens wear before refractive surgery

This was a retrospective study to determine the length of time required to reach refractive stability after discontinuation of rigid contact lens wear for purposes of preoperative evaluation for refractive surgery. Patients were examined at 3-week intervals after discontinuation of rigid contact lens wear, at which time visual acuity, subjective refraction, and corneal topography were performed. Stability was defined 2 consecutive examinations in which the refraction was within ± 0.25 diopter (D) sphere and 0.25 D cylinder with less than 25 degrees of axis orientation. Thirty-one (56.4%) of 55 eyes achieved stability by the second visit, suggesting that stability had been achieved within 3 weeks of discontinuation of lens wear. Twenty-four (43.6%) eyes required more than 2 visits to achieve stability, confirming instability still existed 3 weeks after discontinuation of lens wear. The number of years of contact lens was statistically significantly correlated with the likelihood of requiring longer time to reach refractive stability (P = .05). No statistically-significant between-group difference was observed in age, gender, refractive cylinder, topographic cylinder, difference between refractive and topographic cylinders, surface irregularity index, surface asymmetry index, or spherical equivalent at initial examination. The conclusion was that the length of time required to reach refractive stability after cessation of rigid contact lens wear is highly variable, especially for long-term wearers, and that the customary 3-week interval used by many refractive surgeons does not always allow sufficient time to obtain accurate preoperative measurements. —Michael D. Wagoner This was a retrospective study to determine the length of time required to reach refractive stability after discontinuation of rigid contact lens wear for purposes of preoperative evaluation for refractive surgery. Patients were examined at 3-week intervals after discontinuation of rigid contact lens wear, at which time visual acuity, subjective refraction, and corneal topography were performed. Stability was defined 2 consecutive examinations in which the refraction was within ± 0.25 diopter (D) sphere and 0.25 D cylinder with less than 25 degrees of axis orientation. Thirty-one (56.4%) of 55 eyes achieved stability by the second visit, suggesting that stability had been achieved within 3 weeks of discontinuation of lens wear. Twenty-four (43.6%) eyes required more than 2 visits to achieve stability, confirming instability still existed 3 weeks after discontinuation of lens wear. The number of years of contact lens was statistically significantly correlated with the likelihood of requiring longer time to reach refractive stability (P = .05). No statistically-significant between-group difference was observed in age, gender, refractive cylinder, topographic cylinder, difference between refractive and topographic cylinders, surface irregularity index, surface asymmetry index, or spherical equivalent at initial examination. The conclusion was that the length of time required to reach refractive stability after cessation of rigid contact lens wear is highly variable, especially for long-term wearers, and that the customary 3-week interval used by many refractive surgeons does not always allow sufficient time to obtain accurate preoperative measurements. —Michael D. Wagoner

Kinetics of high-heeled gait.

A within-subject comparative study of walking while wearing low-heeled sports shoes versus high-heeled dress shoes was performed to identify and describe changes in lower-extremity joint kinetics associated with wearing high-heeled shoes during level overground walking. A volunteer sample of 15 unimpaired female subjects recruited from the local community underwent quantitative measurement of sagittal and frontal plane lower-extremity joint function, including angular motion, muscular moment, power, and work. When walking in high-heeled shoes, a significant reduction in ankle plantar flexor muscle moment, power, and work occurred during the stance phase, whereas increased work was performed by the hip flexor muscles during the transition from stance to swing. In the frontal plane, increased hip and knee varus moments were present. These differences demonstrate that walking in high-heeled shoes alters lower-extremity joint kinetic function. Reduced effectiveness of the ankle plantar flexors during late stance results in a compensatory enhanced hip flexor "pull-off" that assists in limb advancement during the stance-to-swing transition. Larger muscle moments and increased work occur at the hip and knee, which may predispose long-term wearers of high-heeled shoes to musculoskeletal pain.

Corneal Exhaustion Syndrome with Long-Term Wear of Contact Lenses

After many years of successful contact lens wear, 3 long-term wearers of polymethyl methacrylate (PMMA) lenses (14, 15, and 18 years) and 1 long-term wearer of thick hydrogel lenses (11 years) suddenly developed intolerance to their lenses. Symptoms included ocular discomfort, reduced vision, and photophobia. All patients exhibited an excessive open-eye edema response with low to moderate Dk lenses. Posterior corneal changes included distortion of the endothelial mosaic and moderate to severe endothelial polymegethism. Patients were successfully refitted with lenses having higher oxygen transmissibility. It is proposed that long-term hypoxia and acidosis accompanying PMMA and thick hydrogel contact lens wear may be responsible for a syndrome characterized by endothelial dysfunction which results in inadequate regulation of corneal hydration and subsequent intolerance to contact lens wear. This condition has been termed Corneal Exhaustion Syndrome (CES).

Research into the pathogenesis of keratoconus. A new syndrome: low ocular rigidity, contact lenses, and keratoconus.

Ocular rigidity determinations were carried out in three groups of patients who were successful long-term wearers of corneal contact lenses. Group 1 consisted of those patients whose corneas showed no refractive changes upon removal of the lenses (as compared to their precontact refraction). Group 2 were patients who had developed permanent with-the-rule astigmatism. Group 3 were patients who developed keratoconus. Though our series is too small for statistical analysis, it would appear that at least one type of keratoconus may be related to the long-term wearing of corneal contact lenses on eyes that have an unusually low ocular rigidity.