Objective and subjective visual performance of multifocal contact lenses: Pilot study

PurposeThe aim of the present study was to compare the objective and subjective visual performance of three different soft multifocal contact lenses.Methods10 subjects (habitual soft contact lens wearers) between the ages of 40 and 45 years participated in the study. Three different multifocal silicone hydrogel contact lenses (Acuvue Oasys, Air Optix and Biofinity) were fit within the same visit. All the lenses were fit according to the manufacturers’ recommendation using the respective fitting guide. Visual performance tests included low and high contrast distance and near visual acuity, contrast sensitivity, range of clear vision and through-focus curve. Objective visual performance tests included measurement of open field accommodative response at different defocus levels and optical aberrations at different viewing distances.ResultsAccommodative response was not significantly different between the three types of multifocal contact lenses at each of the accommodative stimulus levels (p > 0.05). Accommodative lag increased for higher stimulus levels for all 3 types of contact lenses. Ocular aberrations were not significantly different between these 3 contact lens designs at each of the different viewing distances (p > 0.05). In addition, optical aberrations did not significantly differ between different viewing distances for any of these lenses (p > 0.05). ANOVA revealed no significant difference in high and low contrast distance visual acuity as well as near visual acuity and contrast sensitivity function between the 3 multifocal contact lenses and spectacles (p > 0.05).ConclusionsThere was no statistically significant difference in accommodative response, optical aberrations or visual performance between the 3 multifocal contact lenses in early presbyopes.     

Dynamics of the accommodative response and facility with dual-focus soft contact lenses for myopia control

ObjectiveTo assess the impact of using dual-focus soft contact lenses for myopia control on the dynamics of the accommodative response and facility.Methods24 young adult myopes were fitted with dual-focus soft contact lenses for myopia control (MiSight®) and single-vision soft contact lenses (Proclear®). The WAM-5500 open-field autorefractor was used to measure the dynamics of the accommodative response (magnitude and variability) in binocular conditions, with accommodative data being gathered from the dominant eye, at three viewing distances (500 cm, 40 cm, and 20 cm) during 90 s. Also, the binocular accommodative facility was assessed with the WAM-5500 autorefractor. All participants performed the same experimental protocol with the dual-focus (MiSight) and single-vision (Proclear) soft contact lenses, with both experimental sessions being carried in two different days and following a counterbalanced order.ResultsThis study showed greater lags of accommodation with the MiSight than the Proclear lenses at near distances (40 cm: 1.27 ± 0.77 vs. 0.68 ± 0.37 D, corrected p-value = 0.002, Cohen-d = 0.90; and 20 cm: 1.47 ± 0.84 vs. 1.01 ± 0.52 D, corrected p-value = 0.007, Cohen-d = 0.75), whereas a higher variability of accommodation was observed with the dual-focus than the single-vision lenses at 500 cm (0.53 ± 0.11 vs. 0.23 ± 0.10 D), 40 cm (0.82 ± 0.31 vs. 0.68 ± 0.37 D), and 20 cm (1.50 ± 0.56 vs. 1.15 ± 0.39 D) (corrected p-value < 0.001 in all cases, and Cohen-ds = 0.67–2.33). Also, a worse quantitative (27.75 ± 8.79 vs. 34.29 ± 10.08 cycles per minute, p = 0.029, Cohen-d = 0.48) and qualitative (23.68 ± 7.12 vs. 28.43 ± 7.97 score, p = 0.039, Cohen-d = 0.45) performance was observed with the MiSight when compared to the Proclear lenses.ConclusionsThe use of dual-focus soft contact lenses for myopia control alters the dynamics of accommodative response and facility in the short-term. Although this optical design has demonstrated its effectiveness for myopia control, eye care specialists should be aware of the acute effects of these lenses on accommodation performance.     

Light distortion of soft multifocal contact lenses with different pupil size and shape

PurposeTo study the light distortion effects of soft multifocal contact lenses and the influence of different pupil size and shape.MethodsA total of 14 eyes of 7 healthy contact lens users (mean age 28.6 ± 8.5 years) were recruited. The “Light Disturbance Analyser” device was employed for light characterization. The selected lenses were the monthly disposable “Biofinity multifocal” (CooperVision, CA, USA), both centre-distance and centre-near designs (addition power +2.50 D). Two circular pupils of 3 mm and 5 mm of diameter, and an elliptical shape (3 horizontal and 5 vertical mm) were used. Metrics such as the light distortion index (LDI), best-fit circle radius and its irregularity were analysed, among others.ResultsThe LDI was generally higher with multifocal lenses, varying from 3.7 ± 0.3 % of the single vision lens to 6.1 ± 3.3 % of the multifocal centre-distance design and the 5-mm pupil. Larger pupils gave higher LDI values, changing from 4.5 ± 2.0 % (3 mm) to 6.1 ± 3.3 % (5 mm) with the centre-distance design. The elliptical pupil produced the largest discrepancy in the distortion size between the vertical and horizontal directions. The centre-distance and centre-near designs behaved similarly in terms of light distortion.ConclusionsThe multifocal contact lenses of the study increased light distortion effects under low light conditions, especially with larger pupils. The shape of the distortion pattern is associated with the shape of the pupil. It seems that not all, but a big percentage of light distortion would be produced by the presence of the out-of-focus images given by a multifocal lens.     

Rehabilitation of vision disabling corneal opacities: Is there hope without corneal transplant?

ObjectiveTo evaluate the efficacy of contact lenses in visual rehabilitation of a series of patients with corneal scars/opacities.MethodRetrospective review of case records of 158 patients (n = 162 eyes) with poor vision subsequent to corneal scar/opacity, who underwent contact lens fitting, was done. Primary outcome assessed was quantum of additional improvement in vision with rigid gas permeable (RGP) or soft lenses over spectacles. Success was defined as visual improvement of ≥2 lines over that of spectacles and/or improvement of vision to ≥20/60 (LogMAR 0.48).ResultsRigid gas permeable lenses were fitted in 137 eyes and soft contact lenses in 25 eyes. Lenses were successful in improving visual acuity by two or more lines over that of spectacles in 70% eyes (113 of 162 eyes), of which RGP lens accounted for 85% (96 of 113 eyes). Alternative outcome of success was defined as attainment of reasonable functional vision of >20/60 (LogMAR 0.48). This could be achieved in 65% cases (105 of 162 eyes) of which 83% (88 eyes) were with use of RGP lenses. Almost one-fourth (23.4%) patients were children less than 15 years old. Soft contact lenses were attempted in 25 instances, where RGP lens could not be fitted and were successful in 17 (68%) of these. All these 17 patients were aphakes.ConclusionsRehabilitation of corneas with visually disabling corneal opacities is possible with usage of appropriate contact lenses even in young children.     

Which soft contact lens power is better for piggyback fitting in keratoconus?

PurposeTo evaluate the impact of differente soft contact lens power in the anterior corneal curvature and regularity in subjects with keratoconus.MethodsNineteen subjects (30 eyes) with keratoconus were included in the study. Six corneal topographies were taken with Pentacam Eye System over the naked eye and successively with soft lens (Senofilcon A) powers of −3.00, −1.50, 0.00, +1.50 and +3.00 D. Corneal measurements of mean central keratometry (MCK), maximum tangential curvature (TK), maximum front elevation (MFE) and eccentricity (Ecc) at 6 and 8 mm diameters as well as anterior corneal surface high order aberrations (i.e. total RMS, spherical- and coma-like and secondary astigmatism) were evaluated.ResultsNegative- and plano-powered soft lenses flattened (p < 0.05 in all cases), whereas positive-powered lenses did not induce any significant changes (p > 0.05 in all cases) in MCK in comparison to the naked eye. The TK power decreased with negative lenses (p < 0.05 in both cases) and increased with +3.00 D lenses (p = 0.03) in comparison to the naked eye. No statistically significant differences were found in MFE with any soft lens power in comparison to the naked eye (p > 0.05 in all cases). Corneal eccentricity increased at 8 mm diameter for all lens powers (p < 0.05 in all cases). No statistically differences were found in HOA RMS and spherical-like aberration (both p > 0.05). Statistically differences were found in coma-like and secondary astigmatism (both p < 0.05).ConclusionNegative-powered soft contact lenses provide a flatter anterior surface in comparison to positive-powered lenses in subjects with keratoconus and thus they might be more suitable for piggyback contact lens fitting.     

Peripheral myopization and visual performance with experimental rigid gas permeable and soft contact lens design

PurposeTo evaluate the performance of two experimental contact lenses (CL) designed to induce relative peripheral myopic defocus in myopic eyes.MethodsTen right eyes of 10 subjects were fitted with three different CL: a soft experimental lens (ExpSCL), a rigid gas permeable experimental lens (ExpRGP) and a standard RGP lens made of the same material (StdRGP). Central and peripheral refraction was measured using a Grand Seiko open-field autorefractometer across the central 60° of the horizontal visual field. Ocular aberrations were measured with a Hartman-Shack aberrometer, and monocular contrast sensitivity function (CSF) was measured with a VCTS6500 without and with the three contact lenses.ResultsBoth experimental lenses were able to increase significantly the relative peripheral myopic defocus up to −0.50 D in the nasal field and −1.00 D in the temporal field (p < 0.05). The ExpRGP induced a significantly higher myopic defocus in the temporal field compared to the ExpSCL. ExpSCL induced significantly lower levels of Spherical-like HOA than ExpRGP for the 5 mm pupil size (p < 0.05). Both experimental lenses kept CSF within normal limits without any statistically significant change from baseline (p > 0.05).ConclusionsRGP lens design seems to be more effective to induce a significant myopic change in the relative peripheral refractive error. Both lenses preserve a good visual performance. The worsened optical quality observed in ExpRGP was due to an increased coma-like and spherical-like HOA. However, no impact on the visual quality as measured by CSF was observed.     

Contact lens prescribing trends in the UK hospital eye service

PurposeThe aim of this study was to evaluate the types of contact lenses fitted by hospital optometrists within the Midlands region of the United Kingdom (UK).MethodA questionnaire was sent to all the lead optometrists of the Midlands Hospital Optometry Group (MHOG). This group includes optometry hospital eye departments within the Midlands region of the UK. The questionnaire requested information of their last ten contact lens fitting appointments. Details of the patient’s age, gender, lens type, wearing times, and presenting condition were retrospectively taken from the patients’ records using the appointment diary to identify the last ten patients fitted with contact lenses.ResultsDetails from a total of 109 contact lens fits were collected. This included 45 females and 64 males with a mean age of 39.4 ± 17.4 years. The mean wearing time was 6.3 ± 1.0 days per week and 10.7 ± 5.1 h per day. Sixty-one percent of the contact lenses fitted were for patients with keratoconus and over half of all the contact lenses fitted were corneal rigid gas permeable lenses.ConclusionThis study highlighted that the main reason for fitting contact lenses in hospital contact lens practice is primary corneal ectasia, and mainly keratoconus. Whilst most patients with keratoconus were fitted with corneal rigid gas permeable contact lenses, around 1 in 6 were fitted with soft contact lenses. This study addresses a gap in the literature about contact lenses fitted in UK hospitals and how they differ from community contact lens practice.     

Visual performance with multifocal contact lenses and progressive addition spectacles

PurposeAs presbyopia occurs, new visual demands create a need for clear vision at multiple distances. Many spectacle wearers adapt into progressive addition lenses (PAL) in order to see clearly at distance, intermediate, and near. A multifocal contact lens provides the ability to see at these same distances without the prismatic effects of a spectacle lens or the peripheral obstruction of a spectacle frame. No studies have been done to date comparing the effect of these types of presbyopic vision correction on a variety of tests of visual performance representative of everyday tasks.MethodsA battery of visual performance tasks were completed by subjects while wearing their habitual PAL spectacles. These subjects were then fit with a multifocal contact lens and wore lenses for 2 weeks or more before completing the tasks again. These functional vision tests included assessments of coincidence anticipation timing, peripheral search and hand-eye coordination, and dynamic visual acuity. Following functional vision testing, subjects completed a preference survey comparing both types of refractive correction while performing common activities of daily living.ResultsPerformance on the majority of the tests of visual performance were equivalent (P < 0.05) when comparing PAL spectacles and multifocal contact lenses. Survey results demonstrated a preference for multifocal contact lenses overall.ConclusionPAL spectacles are widely prescribed for presbyopic patients. The findings of this study suggest that in addition to providing excellent vision, multifocal contact lenses provide functional vision performance equal to PAL spectacle wear and patients may prefer them over PAL spectacles.     

Stabilization of comfort and visual quality after the insertion of soft contact lenses

PurposeTo evaluate comfort, visual function, and in vivo wettability after the insertion of hydrogel and silicone hydrogel contact lenses for a better understanding of how long practitioners should wait for the initial evaluation of soft contact lenses.MethodsA short-term prospective, contralateral, randomized, and participant-masked study was carried out. Twenty healthy participants (25.4 ± 2.6 years) were evaluated after the insertion of two different soft contact lenses at different times (1, 5, 10, 20, 30 min). Ocufilcon D (hydrogel) and Somofilcon A (silicone hydrogel) contact lenses were randomly assigned to both eyes of the same participant. Comfort, visual function under photopic conditions in terms of high-contrast visual acuity, low-contrast visual acuity, contrast sensitivity, and in vivo wettability were measured.ResultsThere was an increase in comfort (p < 0.001), high-contrast visual acuity (p < 0.05), and contrast sensitivity (p < 0.001, only with silicone hydrogel) directly related to time after contact lens insertion. Besides, in vivo wettability suffered a statistically significant deterioration directly related to time with both contact lenses (p < 0.05). Except for comfort and contrast sensitivity, all the parameters stabilized their values 10 min after the insertion of both soft contact lenses. Additionally, in vivo wettability and visual acuity differences were found between hydrogel and silicone hydrogel contact lenses (p < 0.05).ConclusionsIt would be possible to properly evaluate high-contrast visual acuity, low-contrast visual acuity, and in vivo wettability 10 min after the insertion of both soft contact lenses.     

Efficacy of spherical aberration correction based on contact lens power

PurposeTo investigate the efficacy of spherical aberration (SA) correction with aspheric contact lenses (aspheric lenses) based on lens power, and compare the results with those of spherical contact lenses (spherical lenses).MethodsOcular higher-order aberrations were measured with a wavefront sensor, in 11 myopic subjects wearing an aspheric lens (Medalist Fresh fit (PUREVISION 2 HD); Bausch + Lomb) or a spherical lens (ACUVUE Oasys; Johnson & Johnson). Six different lens powers (−7.00 diopters (D), −5.00 D, −3.00 D, −1.00 D, +1.00 D, +3.00 D) were used for all subjects. The amount of SA correction from the contact lens at each power was calculated as the difference between SA with the contact lens on-eye and SA of the eye alone.ResultsFor the spherical lenses, SA correction was close to 0.00 μm for the +1.00 D lens, became more positive as the labeled lens power increased and became more negative as the labeled lens power decreased. For the aspheric lenses, SA correction was consistent, from −0.15 to −0.05 μm, for all lens powers except for the −1.00 D lens. SA correction for the spherical and aspheric lenses was significantly different at −7.00 D (p = 0.040), −3.00 D (p = 0.015), −1.00 D (p < 0.001), +1.00 D (p = 0.006), and +3.00 D (p < 0.001) powers.ConclusionAn aspheric lens is capable of correcting SA at different lens powers, and has SA correction in the range of −0.15 to −0.05 μm over a 6 mm aperture.     

Optimizing correction of coma aberration in keratoconus with a novel soft contact lens

PurposeTo report on a second-generation prototype contact lens (modified lens) with enhanced optics to correct coma aberration and compare its performance with that of the prototype contact lens (conventional lens) used to optimise correction of coma aberration in keratoconus (KC).MethodsBoth lenses were designed as a set of standardised soft contact lenses (SCLs) with asymmetric powers along the posterior surface. The modified lens differs from the conventional lens in that the optical zone is decentred superiorly by 0.7 mm. The on-eye performance was compared between the SCLs and no-lens wearing in terms of manifest refraction, corrected distance visual acuity (CDVA), ocular aberrations, subjective quality of vision, and on-eye lens position relative to the pupil.ResultsThirty-four KC eyes were included. SCLs significantly decreased coma aberration compared to no-lens wear (none, 0.68 ± 0.27 μm; conventional lens, 0.37 ± 0.28 μm; modified lens, 0.19 ± 0.15 μm; P < 0.001), with the reduction in coma aberration being significantly greater with the modified lens than with the conventional lens (P = 0.018). No significant difference in manifest refraction or CDVA was found among the three conditions. Quality of vision was significantly better with the modified lens than with no SCL wear (P < 0.05) but no differences were found between the SCLs. The on-eye optical center position relative to the pupil was closer to the pupil centre using the modified lens than the conventional lens (P < 0.001).ConclusionOptimisation of the location of the optical zone in a standardised asymmetric SCL improves correction of coma aberrations and on-eye optical centration.     

The association of comfort and vision in soft toric contact lens wear

PurposeThis work set out to investigate if there was an association between subjective comfort and both subjective and measured vision during the use of contemporary daily disposable soft toric contact lenses.MethodsThirty-eight habitual soft contact lens wearers wore each of three daily disposable toric lenses for one week in a prospective, crossover, randomised, single-masked study. The following clinical measures were recorded at dispensing and follow-up visits: biomicroscopy scores, lens fitting (including rotation and rotational stability), high and low contrast visual acuity, subjective vision quality and subjective ocular surface comfort. Subjective scores were collected using 0–10 numerical grading scales. Comfort scores were analysed using a linear regression model with age, sex, visit, phase of crossover (‘phase’), lens type, lens rotation, lens rotational stability, visual acuity, cylinder power and subjective vision quality as factors of interest and then refined using backward stepwise regression.ResultsThirty six participants (31.1 ± 13.5 years) completed the study. Comfort scores were found to be associated with subjective vision quality (F = 127.0 ; p < 0.0001), phase (F = 7.2; p = 0.001) and lens type (F = 4.9; p = 0.009). Greater comfort scores were observed with greater subjective vision quality scores. Visual acuity was not statistically significant in the model.ConclusionThis work suggests that symptoms of ocular discomfort may be more intense if there is also perceived visual compromise in daily disposable soft toric lenses. There was a stronger positive correlation between comfort and subjective vision quality compared with comfort and measured visual acuity.     

The effect of concentric and aspheric multifocal soft contact lenses on binocular vision in young adult myopes

PurposeMultifocal soft contact lenses (MFCLs) are prescribed to inhibit myopia progression; these include aspheric and concentric designs. The effects of MFCLs on visual quality, accommodation and vergence in young-adult myopes were evaluated.MethodsParticipants were twenty-six myopes (19–25 years, spherical equivalent ?0.50 to ?5.75D), with normal binocular vision and no past myopia control. Pupil sizes were 4.4 ± 0.9 mm during distance viewing and 3.7 ± 0.8 mm at near. In random order, participants wore four MFCLs: Proclear single vision distance, MiSight concentric dual focus (+2.00D), distance center aspheric (Biofinity, +2.50D) (CooperVision lenses), and NaturalVue aspheric (Visioneering Technologies). Testing included visual acuity, contrast sensitivity (Pelli-Robson), stereoacuity, accommodation response, negative and positive relative accommodation, horizontal phorias, horizontal fusional vergence and AC/A ratio, and a visual quality questionnaire.ResultsThe four lenses differed in distance (p = 0.001) and near visual acuity (p = 0.011), and contrast sensitivity (p = 0.001). Compared with the single vision lens, the Biofinity aspheric had the greatest visual impact: 0.19 ± 0.14 logMAR distance acuity reduction, 0.22 ± 0.15 log contrast sensitivity reduction. Near acuity was affected less than distance acuity; the reduction was greatest with the NaturalVue (0.05 ± 0.07 logMAR reduction). The MFCLs altered the autorefraction measure at distance and near (p = 0.001); the accommodation response was less with aspheric lenses. Negative relative accommodation reduced with the aspheric lenses (p = 0.001): by 0.9 ± 0.5D with Biofinity and 0.5 ± 0.7D with NaturalVue. Exophoric shifts were greater with aspheric lenses (1.8 ± 2.4Δ Biofinity, 1.7 ± 1.7Δ NaturalVue) than with the concentric MiSight (0.5 ± 1.3Δ).ConclusionsMFCLs alter visual performance, refraction and vergence; two aspheric lenses had greater effect than a concentric lens.     

Accommodation and vergence function in children using atropine combined with orthokeratology

PurposeThis study aimed to evaluate binocular vision in terms of vergence and accommodative measurements in children treated with 0.01% atropine combined with orthokeratology (OK).MethodsThis was a prospective and randomized controlled clinical trial involving participants aged 8 to 12 years, with a spherical equivalent (SE) ranging from ? 1.00 to ? 6.00D. Participants were randomly divided into four groups: 1) a combination group using 0.01% atropine solution and OK lens; 2) an OK group using placebo solution and OK lens; 3) an atropine group using 0.01% atropine solution and wearing spectacles; and 4) a control group using placebo solution and wearing spectacles. Binocular vision was determined at baseline and at 3-month visits, with evaluations including horizontal phoria, fusional vergence, the accommodative convergence/accommodation (AC/A) ratio, accommodative lag, and accommodative amplitude (AA). The Wilcoxon signed-rank test was used to compare the changes in binocular vision in each group, and the Kruskal–Wallis test was used for comparisons of four groups.ResultsSixty-two participants completed the study. There was no significant difference in baseline refraction, accommodation or vergence measurements among the groups (all P > 0.05). Three months later, the accommodative lag significantly decreased in the OK group (P = 0.002) but remained unchanged in the other three groups (all P > 0.05). In addition, binocular accommodative facilities and positive relative accommodations increased in the combination and OK groups (both P < 0.05) but remained unchanged in the atropine and control groups (both P > 0.05). Only the participants with esophoria in the OK group had a significant decrease in esophoria (P = 0.008). Moreover, the changes in fusional vergence and AC/A did not significantly differ between the four groups (all P > 0.05).ConclusionAccommodative measurements changed similarly in the groups treated with OK. Changes in vergence measurements after treatment with 0.01% atropine were not significant.     

Orthokeratology in adults and effect on quality of life

ObjectiveTo determine changes in various ocular parameters of adults wearing orthokeratology (ortho-k) lenses and their levels of satisfaction and quality of life (QoL) after commencing treatment.MethodsAdults aged 18–38 years, with mild to moderate myopia and astigmatism < 1.50D, were wearing ortho-k lenses for one year. Data collection, which included history taking, refraction, axial length (AL), corneal topography, corneal biomechanics, and biomicroscopy examination, was performed at baseline and every 6 months during the study period. The level of satisfaction with the treatment and QoL was determined via questionnaires.ResultsForty-four subjects completed the study. AL was shortened significantly at the 12-month visit: AL −0.03 (-0.45 to 0.13) mm compared to baseline (p < 0.05). A significant number of subjects in both groups presented with overall and central corneal staining, but the majority were mild (Grade 1). Central endothelial cell density was reduced by 40/mm² (loss rate 1.4 %) (p < 0.05). High scores were obtained in the satisfaction questionnaire, with no significant differences between visits. At the 12-month visit, NEI-RQL-42 total score, dependence on correction, activity limitation, appearance, and satisfaction with the treatment all significantly increased compared to baseline values.ConclusionsResults suggest that ortho-k can be an effective and safe myopia correction technique for adults with low to moderate myopia, improving daytime vision without serious adverse events. Satisfaction with ortho-k lens wear was high, particularly those who were dependent on vision correction and found spectacles or contact lenses limiting specific activities or cosmetically undesirable.     

Disability glare in soft multifocal contact lenses

Purpose

The study investigated the effect of the design of multifocal contact lenses on the sensitivity to contrast and disability glare.

Predicting success with silicone-hydrogel contact lenses in new wearers

Purposeto evaluate changes in tear metrics and ocular signs induced by six months of silicone-hydrogel contact lens wear and the difference in baseline characteristics between those who successfully continued in contact lens wear compared to those that did not.MethodsNon-invasive Keratograph, Tearscope and fluorescein tear break-up times (TBUTs), tear meniscus height, bulbar and limbal hyperaemia, lid-parallel conjunctival folds (LIPCOF), phenol red thread, fluorescein and lissamine-green staining, and lid wiper epitheliopathy were measured on 60 new contact lens wearers fitted with monthly silicone-hydrogels (average age 36 ± 14 years, 40 females). Symptoms were evaluated by the Ocular Surface Disease Index (OSDI). After six months full time contact lens wear the above metrics were re-measured on those patients still in contact lens wear (n = 33). The initial measurements were also compared between the group still wearing lenses after six months and those who had ceased lens wear (n = 27).ResultsThere were significant changes in tear meniscus height (p = 0.031), bulbar hyperaemia (p = 0.011), fluorescein TBUT (p = 0.027), corneal (p = 0.007) and conjunctival (p = 0.009) staining, LIPCOF (p = 0.011) and lid wiper epitheliopathy (p = 0.002) after six months of silicone-hydrogel wear. Successful wearers had a higher non-invasive (17.0 ± 8.2 s vs 12.0 ± 5.6 s; p = 0.001) and fluorescein (10.7 ± 6.4 s vs 7.5 ± 4.7 s; p = 0.001) TBUT than drop-outs, although OSDI (cut-off 4.2) was also a strong predictor of success.ConclusionSilicone-hydrogel lenses induced significant changes in the tear film and ocular surface as well as lid margin staining. Wettability of the ocular surface is the main factor affecting contact lens drop-out.     

A novel collaboration: Multifocal RGPs and low vision aids increase quality of life in visually impaired

ObjectivesBy presenting 2 cases, this study aimed to discuss the utility of multifocal rigid gas permeable contact lenses in the low vision patient population, and their ability to decrease reliance on low vision aids and to increase quality of life.MethodsA retrospective case series of 2 patients receiving care from two specialty practice locations was performed. Both patients were visually impaired presbyopic myopes, and sought care from both contact lens and low vision specialties in order to improve visual function and enhance their ability to perform activities of daily living. They were each fit with multifocal gas permeable contact lenses to be used in conjunction with low vision devices. The Visual Functioning Questionnaire – 25 was administered to both patients in order to quantify improvement to quality of life with the new contact lenses.ResultsBoth patients were successfully fit with multifocal gas permeable contact lenses and reported decreased reliance on low vision aids as well as significant improvement in quality of life when wearing the contact lenses.ConclusionThe use of multifocal rigid gas permeable contact lenses in the low vision patient population may be an effective tool to make visually impaired patients, particularly presbyopic degenerative myopes, less reliant on low vision aids, thereby improving their quality of life.     

Comparison of conventional method of contact lens fitting and software based contact lens fitting with Medmont corneal topographer in eyes with corneal scar

PurposeTo compare conventional method of contact lens fitting with software based contact lens fitting using Medmont corneal topographer in eyes with nebular and macular corneal scars.MethodsFifteen participants who were diagnosed with nebular and macular scars were fitted with rigid gas permeable lenses using conventional method of contact lens fitting. During the lens dispensing visit, participants underwent Medmont corneal topography. Agreement between the two methods of contact lens fitting was studied.ResultsParameters of contact lenses which were concluded using conventional method was compared to that of software based fitting. Mean difference in base curve of contact lens between the two methods was 0.094 mm ± 0.147 mm (95% CI: +0.383 to −0.194). Mean difference in diameter of contact lens between the two methods was 0.16 mm ± 0.172 mm (95% CI: +0.497 to −0.177). Contact lens parameters that were achieved using two different methods of fitting showed good correlation. Correlation coefficients, as comparison of two methods in base curve and diameter were 0.96 (P < 0.05) and 0.94 (P < 0.05), respectively.ConclusionSoftware based contact lens fitting would be useful for contact lens practitioners to predict initial base curve of contact lens in corneal scars.