Types Of Contact Lenses Research Articles

Heavy metal deposition and parameter change of soft contact lenses by exposure to particulate matter

BackgroundParticulate matter (PM) is known to contain heavy metals and be harmful to the tissues and organs of the human body including the eyes. As such, in this study, the deposition of heavy metals from PM on soft contact lenses was examined, and changes in the lens parameters were further investigated.MethodsSix types of soft contact lenses were exposed to captured PM10 for eight hours. The central thickness, water content, refractive power, and oxygen transmissibility of each contact lens were measured after analyzing the amounts of six heavy metals adsorbed on the contact lenses.ResultsLead, manganese, barium, arsenic, vanadium, and cadmium were detected in the captured PM, and only lead was adsorbed on all soft contact lenses except senofilcon C. The largest deposition was 23.21 ± 0.70 (10− 3)µg/lens of the lead on lotrafilcon B. The oxygen transmissibility of nelfilcon A exhibited statistically significant changes, however, it was within the ISO standard tolerance. Nevertheless, changes in the central thickness, water content, and refractive power of each soft contact lens were not statistically significant.ConclusionsThis study revealed that a considerable amount of lead in PM10 was adsorbed on soft contact lenses. Amongst lens parameters, only oxygen transmissibility changed significantly. Thus, wearing soft contact lenses under high PM10 concentration might affect the physiology of the eyes.

Does dropout happen even with patients fitted with contact lenses for irregular cornea?

Objectives: Different types of contact lenses play a primary role in improving visual acuity in irregular corneas. Although there are multiple evidences for vision improvement with contact lens patients still drop out of lens wear and choose other methods of treatment, surgeries, or discontinue the lenses. Materials and Methods: Three thousand two hundred patients who were evaluated for 5 years at a specialty contact lens clinic in a tertiary eye care center, but did not return to the clinic for over 18 months from the date of dispensing were identified as dropouts. Only 73 patients were identified as falling under this category of dropout. The reasons for dropout were categorized as comfort-related, vision-related, other reasons, and those who underwent surgical procedures. Results: Unlike previous studies, which included soft lenses, this study revealed only 2.28% (73/3200) of dropouts. There were 38 patients with unilateral lens fitting and 35 patients with bilateral lens fitting. The visual acuity was significantly improving with contact lens in these eyes. The clinical presentation of these patients was analyzed to know about their stage of disease while they dropout from the contact lens clinic. Conclusion: Although dropout of contact lens is much lesser in irregular corneal conditions, it is important for the practitioner to be updated with the alternate and latest modality of lens choices to satisfy vision-related and comfort-related issues of patients.

The results of a laboratory and clinical study evaluating the disinfecting properties multifunctional solution “OKVision GOLD” in relation to gas-permeable lenses

Introduction. The modern realities of the Russian market of contact lens care products dictate the search for a universal solution for one-stage cleaning, which has high disinfecting and cleansing properties for all types of contact lens materials.Purpose: investigation of the disinfecting properties of the multifunctional solution “OKVision GOLD” in relation to scleral gas-permeable lenses.Materials and methods. 20 patients (40 eyes) with keratoconus of various stages (average age 32.6 ± 2.3 years) were examined before and after wearing scleral lenses in the daytime. A clinical ophthalmological study was conducted, including a biomicroscopic assessment of the lens surfaces, as well as the anterior segment of the eye with the use of vital dyes before and after lens cleaning. In addition, smears were collected for further bacteriological examination. Evaluated: a) initial smear from the conjunctiva of the patient before putting on the contact lens; b) a smear from two surfaces of the lens after wearing it for 12 hours; c) a smear from two surfaces of the lens after 6 hours of treatment in solution. The place of analysis: G.N. Gabrichevsky research institute for epidemiology and microbiology.Results. Sowing smears from the conjunctiva before using contact correction revealed the presence of opportunistic flora. Sowing after 12 hours of wearing lenses determined the attachment of pathogenic flora. Examination of smears from lens surfaces after their 6-hour exposure in solution revealed complete inactivation of previously detected pathogenic and insignificant presence of conditionally pathogenic flora. During biomicroscopy, the condition of the eye surface remained unchanged, no deposits on the lenses were recorded. The survey of patients also revealed no negative reactions.Conclusion. The results of clinical and bacteriological studies indicate high disinfecting activity against conditionally pathogenic and conditionally pathogenic flora in the treatment of scleral lenses. This solution can be recommended for the care of all types of contact lenses, including gas-permeable ones.

Biomimetic-Engineered Silicone Hydrogel Contact Lens Materials.

Contact lenses are one of the most successful applications of biomaterials. The chemical structure of the polymers used in contact lenses plays an important role in determining the function of contact lenses. Different types of contact lenses have been developed based on the chemical structure of polymers. When designing contact lenses, materials scientists consider factors such as mechanical properties, processing properties, optical properties, histocompatibility, and antifouling properties, to ensure long-term wear with minimal discomfort. Advances in contact lens materials have addressed traditional issues such as oxygen permeability and biocompatibility, improving overall comfort, and duration of use. For example, silicone hydrogel contact lenses with high oxygen permeability were developed to extend the duration of use. In addition, controlling the surface properties of contact lenses in direct contact with the cornea tissue through surface polymer modification mimics the surface morphology of corneal tissue while maintaining the essential properties of the contact lens, a significant improvement for long-term use and reuse of contact lenses. This review presents the material science elements required for advanced contact lenses of the future and summarizes the chemical methods for achieving these goals.

Comparison of visual performance and image quality between a myopia-control contact lens and a single-vision contact lens

ObjectiveThis study aimed to evaluate the visual performance and image quality of concentric dual-focus-designed contact lenses (CLs) compared with single-vision CLs in myopic Chinese people. MethodsTwenty myopic volunteers aged between 18 and 26 years were recruited at a university eye hospital to wear both defocus-incorporated soft contact (DISC) lenses and single-vision CLs for 1 week in random order. High- and low-contrast visual acuity (VA), contrast sensitivity (CS), ocular higher-order aberrations (HOA), Strehl ratio and the Quality of Vision (QoV) questionnaire were assessed with each type of CL at weekly follow-up. ResultsDistance VA was not affected by DISC lenses compared to single-vision CLs in either high (p = 0.414) or low contrast (p = 0.431). However, there was a significant reduction in low-contrast near VA with DISC lenses compared with single-vision CLs (p = 0.011). The differences of CS between DISC lenses and single-vision CLs were significantly associated with lighting conditions and spatial frequencies (F = 128.81, P < 0.001). Compared with single-vision CLs, wavefront aberrations of DISC lenses were significantly increased in total HOA, trefoil, and spherical aberrations for either 3.0 mm or 6.0 mm pupil size. The Strehl ratio wearing DISC lenses reduced significantly compared to the single-vision CLs (p < 0.001) at a pupil diameter of 6.0 mm. QoV scores were higher overall (p = 0.026) and frequency (p = 0.019) with DISC lenses than with single-vision CLs, indicating poorer visual performance. ConclusionDISC lenses provide satisfactory distance VA. However, the higher scores of the QoV questionnaire with DISC lenses may be related to decreased CS at medium or high spatial frequencies and increased higher-order aberrations.

Investigation of Contact Lens Use and Perception among Hospital Workers: A Survey on Contact Lens Use, Knowledge and Attitude among Hospital Workers

Purpose: To investigate the patterns of contact lens (CL) use and knowledge and attitude regarding the CL use among worker at a Kangwon National University Hospital.Methods: QA survey regarding the use of CL and CL-related knowledge and attitude were distributed over 2 month period starting in March, 2021 to Kangwon National University Hospital workers who had experience of CL use. The survey included questions regarding age, gender, occupation, type of CL, reason for wearing, period of use, purchase route, CL wearing pattern, complications, causative factors, and regular eye examination. The answer to each question was collected and analyzed.Results: One hundred and twelve participants completed the survey. The mean age was 30.1±5.8 years and the male-to-female ratio was 1:2.6. Soft and cosmetic CLs comprised the majority (95.5%, 107/112). Most respondents (99.1%, 111/112) purchased their CL from an optical store or through internet without prescription. Only 71.4% (80/112) washed their hands when wearing and removing lenses. In many cases, respondents had incorrect knowledge about method of CL and lens case cleaning. Most respondents 99.1% (111/112) experienced complications like foreign body sensation, dry-eye, hyperemia, blurred vision, tearing, of which only 8.0% (9/112) received regular eye examinations.Conclusions: The study finding showed even hospital workers may have incorrect knowledge regarding use of CL. Although most CL user experienced complications regarding CL, only a small proportion of CL users are receiving regular eyeexamination. Education of CL users regarding the CL care and importance of regular eye examinations are therefore warranted.

Clinical Applications and Complications of Contact Lens Type Amniotic Membrane

Contact lens type amniotic membrane (CLAM) is a promising new approach to using amniotic membrane in ophthalmology. It can be used to treat a range of ocular surface disorders, including dry eye disease, corneal ulcers, and chemical burns. CLAM can help to reduce inflammation, promote epithelialization and wound healing, and improve corneal clarity and vision. Its ease of handling and application, combined with its potential therapeutic benefits, make it an attractive option for treating a range of ocular surface diseases. However, further studies are needed to fully evaluate the safety and efficacy of CLAM, and to optimize its processing and application protocols.

Effect of Contact Lens Design on Objective Visual Acuity-Based Parameters in Pre-Presbyopic Patients in Photopic and Mesopic Lighting Conditions.

Presbyopia is often corrected by progressive soft contact lenses (CL), and the resulting visual acuity-based parameters can be affected by the lens design and pupil size under different lighting conditions. In this study, we examined the effect of CL design (spheric vs. aspheric) on objective parameters of visual acuity-based parameters under mesopic vs. photopic lighting conditions. In a prospective, double-blind study, pre-presbyopic and presbyopic patients were fitted with spheric (Dispo Silk; 8.6 base curve, 14.2 diameter) and aspheric (Dispo Aspheric; 8.4 base curve, 14.4 diameter) CLs. The low contrast (10%) and high contrast (100%) visual acuity (VA), amplitude of accommodation (AA) (push-away method, Diopters) and distance contrast sensitivity (CS) (FACT chart, cycles per degree (CPD)) were measured with both types of CLs under mesopic and photopic lighting conditions. The eye with the better visual acuity was tested and analyzed. Thirteen patients (age range: 38-45 years) were included. The mean CS was significantly better with spheric compared to aspheric lenses for low spatial frequencies (3 CPD: 81.69 ± 7.86, 67.62 ± 5.67, respectively; p < 0.05), though there was no significant difference for lower or higher spatial frequencies (1.5, 6, 12, 18 CPD). The low-contrast (10%) and high-contrast (100%) VAs were not different between the two lens designs. However, there were significant differences between near VA, distance low-contrast VA and AA obtained under mesopic (dim) vs. photopic (bright) conditions with the aspheric design correction modality. In conclusion, photopic lighting conditions improved both the visual acuity and measured amplitude of accommodation with both lens designs, though the amplitude of accommodation was significantly higher with aspheric lenses. However, contrast sensitivity demonstrated the superiority of the spheric lens at a 3 CPD spatial frequency. This suggests that the ideal lens differs from patient to patient, depending on the visual demands.

Contact Lens Use Advice-Risks and Outcomes: Are Patients Drowning in Information but Starved for Knowledge?

Microbial keratitis can cause significant visual morbidity and is a common reason for presentation to eye casualty clinics. Contact lens wear and poor contact lens hygiene significantly increase the risk of corneal infection. This study aimed to determine the level of contact lens hygiene awareness amongst contact lens wearers attending our service and determining whether contact lens type and hygiene attitude are related to severity of disease. This prospective questionnaire-based study included 50 consecutive patients attending the eye casualty clinic of a tertiary referral center. Visual acuity was assessed at presentation and 2 weeks after diagnosis. Patients were divided into subgroups according to contact lens type (monthly, bi-weekly, daily, and extended day and night wear) and risk group (low, medium, and high) depending on their contact lens hygiene practices. Thirty-four women and 16 men were included in this study. Twenty-four patients used monthly disposable contact lenses, 16 used daily disposable contact lenses, 6 were using bi-weekly replacement lenses, and 4 patients were using extended wear (day and night) contact lenses. Twenty-five patients were diagnosed with corneal ulcer, 23 of which had some degree of poor contact lens hygiene. Best corrected visual acuity (BCVA) significantly improved after treatment. Mean BCVA was 0.24 LogMAR before treatment and 0.09 LogMAR after treatment (p<0.05). Our study highlights the need to improve contact lens hygiene awareness and influence hygiene practices. Patients with the poorest contact lens hygiene had slower visual recovery and a higher prevalence of corneal ulcer. Contact lens hygiene advice needs to be clear and reinforced over time.

Comparison of visual performance between peripheral gradient high-addition multifocal soft contact lenses and orthokeratology.

The aim of this study was to evaluate the short-term effects of peripheral gradient high-addition multifocal soft contact lenses (MFSCLs) and orthokeratology (Ortho-K lenses) on visual performance in myopic children. Thirty myopic children participated in this prospective study. Each participant wore different sets of lenses in the following sequence: single-vision spectacles (SVSPs) as a control, MFSCLs and Ortho-K lenses. Ocular aberrations, topography, high-contrast visual acuity (HCVA), low-contrast visual acuity (LCVA) and accommodation of the right eye were measured with each type of correction on a different day. Compared with SVSPs, high-addition MFSCLs and Ortho-K lenses significantly increased all items of aberrations (all p < 0.05) except trefoil (p = 0.17). MFSCLs induced less coma, root mean square of the third-order aberration (RMS3) and higher order aberrations than Ortho-K lenses (all p < 0.05). No significant difference in HCVA was found across the three correction types (F = 1.19, p = 0.39). In terms of LCVA, MFSCLs performed significantly poorer than SVSPs (difference, 0.16 logMAR; p = 0.001) and slightly worse than Ortho-K lenses (difference, 0.08 logMAR; p = 0.35). No significant difference in decentration was found between the two types of contact lenses, and no associations were observed between decentration and visual acuity at both high- and low-contrast levels (all p > 0.05). For MFSCLs, decentration was positively related to coma (r = 0.43, p = 0.02) and RMS3 (r = 0.44, p = 0.02), which was not the case for Ortho-K lenses. Accommodative facility was worse with MFSCLs than Ortho-K lenses (p = 0.001). Multifocal soft contact lenses differed from Ortho-K lenses in aberration profile and LCVA, although decentration was similar. Decentration <1 mm had minimal influence on both HCVA and LCVA for either type of correction, but significantly increased third-order aberrations for MFSCLs, but not Ortho-K lenses.

Corneal Abscess on Mini-scleral Contact Lens: Clinical Case

Mini-scleral lens’ are large diameter rigid lenses that are used to rehabilitate vision when the corneal shape is distorted from disease, scarring or after a corneal graft procedure, however, there are relatively few reports regarding their potential complications, in this case we describe the case of a corneal abscess in a mini-scleral lens wearer with keratoconus in order to determine whether this type of contact lens presents an increased risk of infection.

Application of Convergent Science and Technology toward Ocular Disease Treatment.

Eyes are one of the main critical organs of the body that provide our brain with the most information about the surrounding environment. Disturbance in the activity of this informational organ, resulting from different ocular diseases, could affect the quality of life, so finding appropriate methods for treating ocular disease has attracted lots of attention. This is especially due to the ineffectiveness of the conventional therapeutic method to deliver drugs into the interior parts of the eye, and the also presence of barriers such as tear film, blood-ocular, and blood-retina barriers. Recently, some novel techniques, such as different types of contact lenses, micro and nanoneedles and in situ gels, have been introduced which can overcome the previously mentioned barriers. These novel techniques could enhance the bioavailability of therapeutic components inside the eyes, deliver them to the posterior side of the eyes, release them in a controlled manner, and reduce the side effects of previous methods (such as eye drops). Accordingly, this review paper aims to summarize some of the evidence on the effectiveness of these new techniques for treating ocular disease, their preclinical and clinical progression, current limitations, and future perspectives.

Compliance to contact lens wear and care among Jordanian adults.

To evaluate compliance to contact lens (CL) wear and care routines among adults in Jordan. A cross-sectional study using a questionnaire administered by an interviewer was conducted among adults in Jordan between the months of May and July of the year 2022. Adult (≥ 18 years) contact lens wearers attending work establishments, universities and shopping centers in the cities of Amman, Aqaba and Irbid in Jordan. Compliance to CL wear and care in addition to CL hygiene habits were evaluated. A total of 834 (600 women) participants were included in the study with an age range of 18 to 55 years (average; 25.49 ± 7.75). Soft spherical CLs for myopia correction were worn by 45.6% of the sample, followed by cosmetic CLs (CCL) (43%). Highest compliance rate (99%) was calculated for not sharing CL with others and the lowest rate (24%) was for cleaning the CL case, with an average compliance rate of 72.25% for the sample with all habits surveyed. Medium compliance rates were related to following instructions of CL solution use including avoiding using expired solution or avoiding topping off. Risk factors for non-compliant behaviors included CCL wear, purchasing CL from beauty centers and being 25 years of age or younger. This study which was performed in a non-clinical setting showed that women and young adults comprise the majority of CL wearers in Jordan. Participants were compliant with most CL wear and care behaviors except for cleaning the CL case and attending aftercare visits. Many CL wearers also reported purchasing lenses from beauty centers and online without consulting CL practitioners. There is a need for patient education regarding the hygiene of the CL case, and the necessity for consulting the CL practitioner for the appropriate type of CL including proper wear and care regimen.

Observational Comparison of the Safety and Effectiveness of Myopic Children Wearing Defocus Incorporated Soft Contact Lenses or Orthokeratology Lenses

To observe and compare the effectiveness and safety of controlling myopia in children by wearing defocus incorporated soft contact (DISC) lenses or orthokeratology (OrthoK) lenses. A total of 75 children who came to our hospital between January 2018 and September 2020 were enrolled for this retrospective study. The DISC group consisted of 30 myopic children (60 eyes) wearing peripheral defocal soft incorporated contact lenses during daytime. There were 10 males and 20 females aged (9.9±1.00) years old in this group and their spherical equivalent refractions were (-2.78±0.70) D. The OrthoK group consisted of 45 myopic children (90 eyes) wearing OrthoK lenses. There were 30 female and 15 males aged (9.67±1.11) and their spherical equivalent refractions were (-2.67±0.71) D. All subjects had previously worn prescription glasses for 12 months or longer before they started wearing contact lenses. The subjects were followed up for 12 months once they started wearing contact lenses. The axial changes and corneal and conjunctival complications of the two groups of myopic children were compared and analyzed. Myopic children in both groups experienced relatively rapid increase in ocular axial length while they were wearing prescription glasses, with the ocular axial length increase in the prescription-glass-wearing period being (0.34±0.09) mm in the OrthoK group and (0.37± 0.07) mm in the DISC group. In the 12 months of wearing contact lenses, the ocular axial length of children in the OrthoK group increased by (0.18±0.04) mm, while that of the DISC group increased by (0.19±0.05) mm. The increase in ocular axial length was reduced in both groups after the children were switched to the new myopia prevention methods, showing significant difference ( P<0. 05). The two groups using two different contact lenses had similar axial length increase, showing no significant difference ( P>0.05). During the 12-month period while the subjects wore the two types of contact lenses, the incidence of chronic follicular conjunctivitis was 11.20% in the OrthoK group and 20.00% in the DISC group, with that of the DISC group being slightly higher without showing significant difference ( P>0.05). The incidence of grade-1corneal staining was 66.70% in the OrthoK group and 56.70% in the DISC group, and the incidence of grade-2 corneal staining was 17.80% in the OrthoK group and 16.70% in the DISC group. In other words, the OrthoK group had slightly higher findings, but the difference was not significant ( P>0.05). The incidence of contact lens-associated papillary conjunctivitis was 2.20% in the OrthoK group and 10.00% in the DISC group, which was slightly higher than that in the orthokeratology lens group, but the difference was not significant( P>0.05). Both DISC lenses and OrthoK lenses can effectively control the increase in axial length in myopic children, and their have better effects than those of prescription glasses. The two tyes of contact lenses showed similar effects for controlling axial length increase. Both contact lenses have fewer corneal and conjunctival complications and better safety.

The impacts of contact lenses on the short- and long-term biochemical parameters of tear films and corneal thickness

Introduction: To investigate the effects of long- and short-term use of different types of contact lenses on corneal metabolism and corneal thickness. Materials and Method: The participants were divided into two groups in the study. In the first group, 20 of the 42 patients were administered a rigid gas-permeable lens (RGPL) with a Dk value of 92x10-11, while the remaining wore a soft contact lens with a water content of 38%. We then explored their Lactate Dehydrogenase (LHD) levels to evaluate the hypoxic effect on tear films in short- (8 hours) and long-term (2nd, 3rd, 5th months) and albumin levels to assess mechanical trauma. In the second group, the corneal thickness was measured using a Haag-Streit optical pachymeter before and at the 8th hour and 2nd month following the first set of lenses, and LDH and albumin values were simultaneously evaluated in tear film. Results: The results yielded no significant increase in tear film LDH and albumin levels in the short- and long-term in both the RGPL and the soft contact lens groups with similar age and sex distribution. In the second part, the corneal thickness measurements resulted in an increase of 5.5% in the RGPL group and 3.63% in the soft lens group at the 8th hour of lens use. However, the groups did not significantly differ by baseline corneal thickness at the 2nd-month follow-up. Similarly, there was no significant increase in LDH and albumin levels in the tear film samples of the same group. Conclusion: The absence of a long-term increase in corneal thickness and no elevated levels of albumin and LDH in tear films indicate that contact lenses fit corneal physiology.

Susceptibility Artefact cause by Different Types of Contact Lenses in MRI Brain: A Phantom Study

Susceptibility Artefact cause by Different Types of Contact Lenses in MRI Brain: A Phantom Study

Influence of Specialty Contact Lens Wear on Posterior Corneal Tomography in Keratoconus Subjects.

To evaluate the effect of specialty contact lens (CL) wear on posterior corneal tomography in keratoconus subjects. Patients with keratoconus who were wearing specialty CL were included in this retrospective cohort study. Tomographic parameters were evaluated with Scheimpflug imaging (Pentacam HR) before lens fitting and immediately after removal of CLs worn habitually for a period of several months. Subjects were divided into groups, according to type of lens (corneal, scleral, and hybrid) and keratoconus severity based on Belin/Ambrosio D (BAD-D) score, for further analysis. Thirty-four eyes of 34 subjects diagnosed with keratoconus were included. Mean duration of habitual CL wear was 7.0±0.3 months. For the entire cohort, a small increase in flat keratometric reading at the anterior corneal surface (K1F; P =0.032) and at the posterior surface (K1B; P =0.041) was found. In the corneal CL group (10 eyes; 29.4%), flattening of the anterior corneal curvature was detected (K max ; P =0.015). An increase in K1B value was seen in the scleral CL group (15 eyes; 44.1%) ( P =0.03). Combined topometric indices showed a small but significant difference in the entire cohort ( P <0.05) and in the subgroups of corneal CL wear and of moderate keratoconus (BAD-D score≥7). Various types of specialty CLs exert a differential influence on corneal parameters. A small steepening of keratometry at the posterior surface (K1B) was observed in the scleral lens group. Although corneal lens wear flattens the anterior cornea (K max ), it does not significantly alter the posterior corneal surface.

Affluence and Contact Lens Prescribing.

To assess the impact of national affluence on the extent of prescribing of various types of soft contact lenses. Using information derived from a large bank of contact lens prescribing data, the relationship between the percentage prescribing of daily disposable, toric, silicone hydrogel, and multifocal contact lenses versus the gross domestic product at purchasing parity per capita (GDP [PPP]) was determined for all countries in which contact lens prescribers returned survey forms relating to greater than 100 contact lens fits between 2017 and 2021, inclusive. Data from 39 countries were analyzed, comprising 94,181 contact lens fits. The relationship between percentage contact lens prescribing versus GDP (PPP) was highly statistically significant for daily disposable lenses (r 2 =0.35, P <0.0001), marginally significant for toric lenses (r 2 =0.08, P =0.06), and not significant for silicone hydrogel lenses (r 2 =0.01, P =0.42) or multifocal lenses (r 2 =0.02, P =0.35). The rate of prescribing daily disposable contact lenses, and to a lesser extent toric lenses, is related to national affluence. The contact lens industry, practitioners, and governments/regulatory bodies should remain cognizant of this association and, where possible, reduce cost barriers to the purchase of such contact lens products so that they can be prescribed based on important clinical, refraction, and lifestyle considerations.

Effectiveness of Commonly Used Contact Lens Disinfectants Against SARS-CoV-2.

Objective:To assess the effect of commonly used contact lens disinfectants against severe acute respiratory syndrome corona virus 2 (SARS-CoV-2).Methods:The efficacy of five disinfectant solutions against SARS-CoV-2 was tested in the presence and absence of contact lenses (CLs). Three types of unused CLs (hard gas permeable, soft hydrogel, and soft silicone hydrogel) and worn silicone hydrogel CLs were tested. Contact lenses were infected with SARS-CoV-2 and disinfected at various times, with and without rubbing and rinsing, as per manufacturer's instructions. Reverse-transcriptase polymerase chain reaction (RT-PCR) and viability polymerase chain reaction (PCR) were applied to detect SARS-CoV-2 RNA and viral infectivity of SARS-CoV-2, respectively.Results:In the presence of SARS-CoV-2–infected CLs, no SARS-CoV-2 RNA could be detected when disinfectant solutions were used according to the manufacturer's instructions. When SARS-Co-V2–infected CLs were disinfected without the rub-and-rinse step, SARS-CoV-2 RNA was detected at almost each time interval with each disinfecting solution tested for both new and worn CLs. In the absence of CLs, viable SARS-CoV-2 was detected with all disinfectant solutions except Menicon Progent at all time points.Conclusions:Disinfectant solutions effectively disinfect CLs from SARS-CoV-2 if manufacturer's instructions are followed. The rub-and-rinse regimen is mainly responsible for disinfection. The viability PCR may be useful to indicate potential infectiousness.

Impact of rigid gas-permeable contact lens on keratometric indices and corneal thickness of keratoconus eyes examined with anterior segment optical coherence tomography.

Purpose/AimDetecting keratoconus (KC) progression helps determine the surgical indication for corneal cross-linking (CXL). This retrospective observational study aimed to examine changes in keratometric indices and corneal thickness in patients with KC who used rigid gas-permeable (RGP) contact lenses.Materials and methodsThis study involved 31 eyes (31 patients) diagnosed with KC. No patient had used RGP or any other type of contact lenses for at least 1 month. Corneal topographic data were obtained using three-dimensional anterior segment optical coherence tomography before and after >1 month of RGP lens use.ResultsThe average and maximum keratometry values changed after using an RGP lens (-1.05 ± 1.92 D, p < 0.01 and -1.65 ± 4.20 D, p = 0.04, respectively); the spherical component of the anterior corneal surface became significantly smaller (p = 0.02). No change was observed in the central or thinnest corneal thickness values. Keratometric changes were greater in eyes with severe KC than in those with moderate KC (p = 0.014).ConclusionsKeratometry and spherical components of the anterior corneal surface values decreased after RGP lens use; keratometric changes were greater in eyes with severe KC than in those with moderate KC. Corneal progression indices, including corneal thickness, posterior keratometry, and irregular astigmatism values, mostly remained unchanged. It is important to consider these findings when evaluating corneal topography of KC and preparing CXL.