Tolerance to decentration of biaspheric intraocular lenses with refractive phase-ring extended depth of focus and diffractive trifocal designs

PURPOSE

This study aimed to investigate the in vitro tolerance to decentration of biaspheric intraocular lens (IOLs) with refractive phase-ring extended depth-of-focus (EDOF) and diffractive trifocal designs.

METHODS

This experimental study was carried out at the Department of Optics and Optometry and Vision Science, University of Valencia, Spain. The modulation transfer function (MTF) of the ETLIO130C EDOF and the TFLIO130C trifocal IOLs (AST Products Inc., Billerica, MA, USA) were determined at different levels of decentration for a given wavelength and pupil diameter using the PMTF optical bench (Lambda-X Ophthalmics, Nivelles, Belgium). The modulation transfer function (MTF) curves, the through-focus MTF curves, and the Strehl ratios were measured at 3-mm pupil aperture for 0.25-, 0.50- and 0.75-mm decentration.

RESULTS

The optical design of the trifocal TFLIO130C IOL is robust to small decentrations, with virtually no change in MTF response for 0.25 mm decentration. For greater decentration levels, the MTF response is slightly reduced with increasing decentration. The ETLIO130C EDOF design is robust to decentration, as the MTF response is only minimally affected when increasing the decentration up to 0.75 mm.

CONCLUSIONS

MTF responses are slightly reduced with greater levels of decentration, but the range of focus provided by both trifocal and EDOF designs are preserved. The effects for average levels of decentration reported in the literature are minimum for both IOL designs.

Exploring the Cutting Edge of Vision Science: New Developments in Diagnostics and Treatment of Ocular Surface in Dry Eye Disease

The ocular surface refers to the outermost layer of the eye, which includes the cornea, conjunctiva and eyelids [...].

Changes in visual function and optical and tear film quality in computer users

PURPOSE

To assess changes in visual function and optical and tear film quality in computer users.

METHODS

Forty computer workers and 40 controls were evaluated at the beginning and end of a working day. Symptoms were assessed using the Quality of Vision questionnaire (QoV), 5-item Dry Eye Questionnaire (DEQ-5) and Symptom Assessment in Dry Eye version II (SANDE II). Tear film quality was evaluated using the Medmont E300 dynamic corneal topography tool to measure the tear film surface quality (TFSQ), TFSQ area and auto tear break-up time (TBUT). Optical quality was assessed by measuring high, low and total ocular aberrations with a Hartmann-Shack wavefront sensor. Visual performance was assessed by measuring photopic and mesopic visual acuity, photopic and mesopic contrast sensitivity and light disturbance.

RESULTS

Poorer DEQ-5, QoV and SANDE II scores were obtained in computer workers at the end of the working day compared with controls (p ≤ 0.02). Computer workers exhibited a higher (worse) TFSQ and TFSQ area at visit 2 compared with visit 1 (p ≤ 0.04), while no significant differences in TBUT (p = 0.19) or ocular aberrations were observed (p ≥ 0.09). Additionally, both light disturbance (p ≤ 0.04) and mesopic and photopic contrast sensitivity worsened at several spatial frequencies (p ≤ 0.04) throughout the working day in computer workers, while visual acuity remained unchanged (p ≥ 0.07). In contrast, control subjects exhibited no decrease in any variable during the day.

CONCLUSIONS

While visual acuity remained unchanged, several aspects of visual function and quality of vision decreased over a day of computer use. These changes were accompanied by greater dry eye symptoms and tear film changes, which are likely to have played a fundamental role. The present study provides insight into new metrics to assess digital eye strain.

The effects of breaks on digital eye strain, dry eye and binocular vision: Testing the 20-20-20 rule

PURPOSE

To evaluate the benefits on the eyes of taking breaks based on the 20-20-20 rule.

METHODS

Bespoke computer software using the laptop webcam to assess user breaks, eye gaze and blinking, and emitting personalized reminders of breaks based on the 20-20-20 rule, was downloaded onto the laptops of 29 symptomatic computer users. Digital eye strain (DES), binocular vision and dry eye were assessed before and after two weeks of using the reminders and one week after the discontinuation of the strategy. Binocular measurements included visual acuity, accommodative posture, stereopsis, fixation disparity, ocular alignment, accommodative facility, positive/negative vergences and near point of convergence. Symptoms were evaluated using the computer vision syndrome questionnaire, ocular surface disease index (OSDI), and symptom assessment in dry eye questionnaire (SANDE) versions one and two. Dry eye signs were assessed by measuring tear meniscus height, conjunctival redness, blink rate and incomplete blinking, lipid layer thickness, non-invasive keratograph break-up time, corneal and conjunctival staining and lid wiper epitheliopathy.

RESULTS

A decrease in the duration of computer work and the duration of breaks, along with an increase in the number of breaks taken per day was observed as a result of the 20-20-20 rule reminders (p ≤ 0.015). No changes on any binocular parameter were observed after the management period (p ≥ 0.051), except for an increase in accommodative facility (p = 0.010). Dry eye symptoms and DES decreased with the rule reminders (p ≤ 0.045), although this improvement was not maintained one week after discontinuation (p > 0.05). No changes on any ocular surface and tear film parameter were observed with the rule reminders (p ≥ 0.089).

CONCLUSIONS

The 20-20-20 rule is an effective strategy for reducing DES and dry eye symptoms, although 2 weeks was not enough to considerably improve binocular vision or dry eye signs.

Assessment of meibomian gland drop-out and visibility through a new quantitative method in scleral lens wearers: A one-year follow-up study

OBJECTIVES

To validate a previously developed algorithm based on the visibility of meibomian gland images obtained with Cobra fundus camera and to assess the changes in meibomian glands in scleral lens wearers over one year of lens wear.

METHODS

Infrared meibography was obtained from the upper eyelid using the Cobra fundus camera in forty-three volunteers (34.2 ± 10.1 years). Meibographies were classified into 3 groups: Group 1 = good subjective gland visibility and gland drop-out < 1/3 of the total area; Group 2 = low visibility and gland drop-out < 1/3; and Group 3 = low visibility and gland drop-out > 1/3. Meibomian gland visibility metrics were then calculated using the developed algorithm from the pixel intensity values of meibographies. Repeatability of new metrics and their correlations with gland drop-out were assessed. Meibographies and ocular symptoms were also assessed after 1 year of scleral lens wear in 29 subjects.

RESULTS

Gland drop-out percentage was not statistically different between groups 1 and 2 (p = 0.464). Nevertheless, group 1 showed higher grey pixel intensity values than the other groups. Statistically significant correlations were found between gland visibility metrics and gland drop-out percentage. Repeatability was acceptable for all metrics, coefficient of variation achieving values between 0.52 and 3.18. While ocular symptoms decreased with scleral lens wear (p < 0.001), no statistically significant differences were found in gland drop-out percentage (p = 0.157) and gland visibility metrics (p > 0.217).

CONCLUSIONS

The proposed method can assess meibomian gland visibility in an objective and repeatable way. Scleral lens wear appears to not adversely affect meibomian gland drop-out and visibility while might improve dry eye symptoms after one year of lens wear. These preliminary results should be confirmed with a control group.

Assessment of condition-induced changes on the ocular surface using novel methods to assess the tear film dynamics and the lipid layer

OBJECTIVES

To assess the effects of different condition-induced changes on current and novel ocular surface metrics.

METHODS

Eighty-four healthy volunteers (22.4 ± 2.6 years) participated in this study. The ocular surface and tear film response to (1) computer use, (2) contact lens insertion and (3) tear film instillation during computer use with contact lenses were assessed. Current metrics included the ocular surface disease (OSDI) questionnaire, 5-item dry eye questionnaire (DEQ-5), bulbar redness, tear meniscus height (TMH) and non-invasive keratograph break-up time (NIKBUT). Novel metrics included the lipid layer thickness obtained from the intensity of the reflected Placido disk and the speed of tear film particles post-blink.

RESULTS

Higher dry eye symptoms, TMH and bulbar redness, and lower values in metrics related to the intensity of the Placido disk pattern and to particle speed were found after the computer reading task (p < 0.036). When a contact lens was fitted, lower TMH, NIKBUT and particle speed metrics were obtained (p < 0.044). Mixed ANOVA revealed that artificial tears significantly ameliorated the effect of computer reading on OSDI, DEQ-5, NIKBUT, metrics related to the intensity of the Placido disk pattern and metrics related to particle speed (p < 0.033).

CONCLUSIONS

Computer use and contact lens wear worsened dry eye signs and symptoms, but artificial tears ameliorated this effect. Newly developed methods can serve as a tool to detect changes in the tear film triggered by different ocular surface-disturbing conditions.

Descriptive Analysis of Footplate Position After Myopic Implantable Collamer Lens Implantation Using a Very High-Frequency Ultrasound Robotic Scanner

Purpose

To assess the position of the haptics of the implantable collamer lens (ICL) in myopic eyes using a high-frequency ultrasound robotic scanner.

Methods

This was a prospective, single-arm, observational study carried out at the Instituto Zaldivar SA (Mendoza, Argentina) in a sample of 52 eyes who have been submitted to successful ICL implantation prior to enrollment. Images of the eyes were obtained using a very-high frequency digital ultrasound robotic scanner (VHFDU) to establish the position of the ICL in the posterior chamber and its relation to the ciliary sulcus. New parameters for lens position analysis were also described.

Results

In 81% of cases (42 eyes), the ICL rests on the ciliary body (CB) in both temporal and nasal sides, being slightly lower than 6% (3 eyes) those that rest on the sulcus in both sides, with significant correlations between ICL position and vault values (p<0.05). Cases in which the ICL position was CB-CB yielded central vault values across the whole range determined within the sample, but most of the eyes where the ICL rests on both the sulcus in one side and the CB in the other yield greater central vault values. Correlation was significant between ICL position and retroposition distance on the temporal side (Spearman's rho -0.487, p<0.001). A significant but weaker correlation was also found between ICL position and retroiridian space (p<0.05).

Conclusion

ICL for myopia footplates tend to locate outside of the sulcus in a significant percentage of patients after successful implantation. VHFDU assessment in eyes implanted with an ICL to properly study the lens footplate position and posterior anatomical relations provides important additional information besides post-surgery vault.

The Effects of Soft Contact Lens Wear on The Tear Film and Meibomian Gland Drop-Out and Visibility

As contact lens (CL) wear affects the ocular surface, this cross-sectional study aims to assess the effects of soft CL wear and its duration on the tear film and meibomian gland (MG) drop-out and visibility. Thirty non-CL wearers (22.5 ± 2.3 years) and twenty-four soft CL wearers (23.8 ± 2.2 years) participated in this study. The Keratograph 5M was used to assess the ocular surface. CL users were surveyed on years of CL wear and hours per week. MG visibility was assessed using a previously developed method based on analysing pixel intensity of meibographies. The CL group showed higher gland drop-out (p < 0.001) and lower gland visibility (p < 0.022). Gland drop-out was independently associated with CL wear (p = 0.006). When gland drop-out was excluded, the relative energy of pixel intensity values showed an independent association with CL wear (p = 0.005). Prolonged hours of CL wear were associated with higher dry eye symptoms and entropy of MGs (p < 0.029). A reduction in non-invasive keratograph break-up time was associated with using CLs for ≥8 years (p = 0.030). Overall, gland drop-out was higher and gland visibility lower in soft CL wearers. New gland visibility metrics might help to assess MGs in soft CL wearers quickly and objectively.

Effect of diabetes mellitus on quantitative corneal anatomy – A systemic review

Background: Corneal changes occur as a direct consequence of diabetes mellitus (DM). The central corneal thickness (CCT) is a useful parameter that provides information about the status of the metabolism of the cornea and can therefore help monitor the progression of DM.Aim: The aim of this study was to determine the impact of DM on CCT and its correlation with diabetes duration and glycated haemoglobin (HbA1c) levels.Methods: The systematic review was undertaken to answer: (1) What effect does DM have on CCT values? (2) What effect does DM duration have on CCT values? (3) What effect does HbA1c levels have on CCT values? The Web of Science was used to conduct a computerised search for articles of CCT values in DM.Results: A total of 38 articles that met the criteria for inclusion were included in this systemic review. The researchers found 27 articles that observed increased CCT values in DM patients compared with control subjects. There were six studies in which increased CCT values were related to DM duration and 12 studies in which DM duration did not alter CCT values. Also, eight studies showed that CCT values increased with glycated haemoglobin levels, and 12 studies did not observe this.Conclusion: Diabetes mellitus patients usually present with increased CCT values although there is no unanimity about the effect of DM duration and increased HbA1c levels (poor glycaemic control) in the CCT values of DM patients. 

Short-term tear film stability, optical quality and visual performance in two dual-focus contact lenses for myopia control with different optical designs

Purpose

To assess and compare short‐term visual and optical quality and tear film stability between two dual‐focus (DF) prototype myopia control contact lenses (CLs) having different inner zone diameters.

Methods

Twenty‐eight myopic subjects were included in this randomised, double‐masked crossover study. Refraction, best‐corrected visual acuity (VA) and tear film stability were measured at baseline (i.e., when uncorrected). Subjects were then binocularly fitted with the DF CLs, with only the sensorial dominant eye being assessed. Lenses were of the same material and had inner zone diameters of either 2.1 mm (S design) or 4.0 mm (M design). Visual and physical short‐term lens comfort, over‐refraction, best‐corrected VA, stereopsis at 40 cm, best‐corrected photopic and mesopic contrast sensitivity (CS), size and shape of light disturbance (LD), wavefront aberrations, subjective quality of vision (QoV Questionnaire) and tear film stability were measured for each lens.

Results

Both CL designs decreased tear film stability compared with baseline (p < 0.05). VA and photopic CS were within normal values for the subjects' age with each CL. When comparing lenses, the M design promoted better photopic CS for the 18 cycles per degree spatial frequency (p < 0.001) and better LD (p < 0.02). However, higher‐order aberrations were improved with the S design (p = 0.02). No significant difference between the two CLs was found for QoV scores and tear film stability.

Conclusions

Both DF CLs provided acceptable visual performance under photopic conditions. The 4.0 mm inner zone gave better contrast sensitivity at high frequencies and lower light disturbance, while the 2.1 mm central diameter induced fewer higher‐order aberrations for a 5 mm pupil diameter. Both CLs produced the same subjective visual short‐term lens comfort.

Depth of field and visual performance after implantation of a new hydrophobic trifocal intraocular lens

Purpose

To assess the depth of field (DOF) by means of defocus curve analysis applying different visual acuity criteria in patients following cataract surgery and bilateral implantation of a new trifocal diffractive intraocular lens (IOL).

Methods

Fifty eyes of 25 consecutive patients who underwent implantation of the Asqelio™ trifocal IOL (AST Products Inc., USA) were enrolled in this observational prospective study. Monocular subjective DOF was obtained from defocus curves with absolute and relative criteria of tolerance for different visual acuities values. Patient’s visual satisfaction, postoperative refraction and visual acuity at far, intermediate (67 cm) and near (40 cm) distances were also measured at 1 and 3-months post-surgery. Analysis of variance was used to assess differences in refractive error after the surgical procedure, and paired t-tests were used to assess differences in VA. Patient satisfaction results were reported as percentages.

Results

Spherical equivalent was 0.05 ± 0.23 D and residual cylinder 0.01 ± 0.23 D 3-months after the surgery. Absolute DOF obtained was 3.29 ± 0.91 D considering 0.1 LogMAR as cut-off value, and 4.82 ± 0.69 D when 0.3 logMAR as cutoff value. Relative DOF considering a drop of 0.1 logMAR from maximum visual acuity was 2.57 ± 0.82 D, and 1.27 ± 0.70 D when a drop of 0.04 logMAR was considered. Visual acuities obtained 3-months after the surgery were 0.03 ± 0.13, − 0.05 ± 0.06, 0.03 ± 0.08 and 0.04 ± 0.08 logMAR for uncorrected and best-corrected for distance, and best distance-corrected for intermediate and near distances, respectively. Average response to visual satisfaction queries was 8.24/10 at distance, 8.04/10 at intermediate, and 7.88/10 at near.

Conclusions

Patients implanted with this trifocal IOL showed a significant improvement in visual acuity at different distances providing wide absolute and relative DOF values. The outcomes demonstrate that this lens is predictable yielding good patient satisfaction rates.

Digital display use and contact lens wear: Effects on dry eye signs and symptoms

PURPOSE

To assess the potential additive effects of short-term display use and contact lens (CL) wear on the ocular surface and tear film.

METHODS

Thirty-four healthy volunteers (20.87 ± 2.33 years old) participated in this study. Participants' dry eye symptoms, ocular surface, tear film and pupil size were assessed before and after executing a 20-min reading task on a computer and a smartphone with and without CL wear, or with CL wear and artificial tear instillation. Measurements included the Ocular Surface Disease Index (OSDI) questionnaire; 5-item Dry Eye Questionnaire (DEQ-5); tear meniscus height (TMH); noninvasive keratograph break-up time (NIKBUT); bulbar conjunctival redness (BR) and pupil size.

RESULTS

Higher symptoms were reported after reading on both displays with and without CLs (p ≤ 0.001) for short periods. BR was higher and NIKBUT shorter after reading on the computer regardless of wearing CLs (p ≤ 0.02 and p ≤ 0.02, respectively), while TMH increased for all conditions (p ≤ 0.02) except for CL computer reading (p = 0.23). Reading with CLs did not lead to greater signs of dry eye (BR, NIKBUT) and symptoms compared with reading unaided (p > 0.05), although a smaller increase in TMH was observed when reading on the computer with CLs (p = 0.005). Artificial tear instillation during CL wear led to a smaller increase in symptoms (p ≤ 0.02), a smaller increase in BR (p ≤ 0.04) and a decrease in NIKBUT (p = 0.02) compared to reading without correction.

CONCLUSIONS

Disposable CL wear had no additive effects on signs and symptoms of dry eye when using digital devices for short periods. The instillation of artificial tears is an effective strategy for reducing the impact of display use in CL wearers.

Ocular surface predisposing factors for digital display-induced dry eye

CLINICAL RELEVANCE

The use of digital displays is recognised as a consistent risk factor for dry eye disease.

BACKGROUND

To identify ocular parameters contributing to the impact of computer use on dry eye.

METHODS

The ocular surface of 82 undergraduate students with a mean age of 22.8 ± 2.1 years was assessed at baseline and after reading on a computer for 30 minutes. Measurements included the ocular surface disease index (OSDI) questionnaire, 5-item dry eye questionnaire (DEQ-5), tear meniscus height, non-invasive keratograph break-up time (NIKBUT), conjunctival bulbar redness, meibomian gland dropout percentage, spontaneous blink rate and percentage of incomplete blinks. Multiple linear regressions and generalised linear mixed models were conducted to explore the associations between baseline parameters and pre-task - post-task differences and to predict the impact of computer use, respectively.

RESULTS

Greater dry eye symptoms (p < 0.0005), higher tear meniscus height and conjunctival bulbar redness (p < 0.0005 and p = 0.012, respectively) and shorter NIKBUT (p = 0.03) were obtained after reading on the computer for 30 minutes. The baseline score obtained with the OSDI and DEQ-5 was positively associated with the increase in symptoms with computer use (p < 0.0005), while the change in conjunctival redness and pre-task NIKBUT were associated with the change in NIKBUT (p ≤ 0.005). No ocular surface parameter revealed an association with tear meniscus height changes. Having a positive OSDI score at baseline increased the odds of painful and sore eyes (p = 0.012), while a higher pre-task NIKBUT increased the odds of a reduction in tear stability (p = 0.038).

CONCLUSIONS

Participants with greater dry eye symptoms were more likely to experience a greater increase in symptomatology with computer operation, while the participants with longer NIKBUT and greater conjunctival redness were more likely to suffer a greater reduction in tear stability.

Validation of a new objective method to assess lipid layer thickness without the need of an interferometer

PURPOSE

This study aimed to develop and validate new metrics to objectively assess the lipid layer thickness (LLT) through the analysis of grey intensity values obtained from the Placido disk pattern reflected onto the tear film.

METHODS

Ocular surface parameters were measured using Oculus Keratograph 5 M in 94 healthy volunteers (43.8 ± 26.8 years). Subjects' LLT was subjectively classified into 4 groups using an interferometry-based grading scale. New metrics based on the intensity of the Placido disk images were calculated and compared between groups. The repeatability of the new metrics and their diagnostic ability was analysed through receiver operating characteristics (ROC) curves. The level of agreement between the new objective tool and the existing subjective classification scale was analysed by means accuracy, weighted Kappa index and F-measure.

RESULTS

Mean pixel intensity, median pixel intensity and relative energy at 5.33 s after blinking achieved the highest performance, with a correlation with LLT between r = 0.655 and 0.674 (p < 0.001), sensitivity between 0.92 and 0.94, specificity between 0.79 and 0.81, area under the ROC curve between 0.89 and 0.91, accuracy between 0.76 and 0.77, weighted Kappa index of 0.77 and F-measure between 0.86 and 0.87.

CONCLUSION

The analysis of grey intensity values in videokeratography can be used as an objective tool to assess LLT. These new metrics could be included in a battery of clinical tests as an easy, repeatable, objective and accessible method to improve the detection and monitoring of dry eye disease and meibomian gland dysfunction.

Peripheral refraction of myopic eyes with spectacle lenses correction and lens free emmetropes during accommodation

PURPOSE

To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m (0.50 D) to 0.20 m (5.00 D) in terms of sphere, astigmatism, and spherical equivalent refraction.

METHODS

Refraction was measured at the center, 20 and 40 degrees from the line of sight both nasally and temporally in 15 emmetropic and 25 myopic young healthy subjects with an open field, binocular, infrared autorefractor (Grand Seiko WAM-5500, Hiroshima, Japan). Fixation target was a Maltese cross set at 2.00, 0.50, 0.33 and 0.20 m from the corneal plane. Changes in off-axis refraction with accommodation level were normalized with respect to distance axial values and compared between myopic eyes with spectacle lenses correction and lens free emmetropes.

RESULTS

Off-axis refraction in myopic eyes with spectacle lenses correction was significantly more myopic in the temporal retina compared to lens free emmetropes except for the closest target distance. Relative off-axis refractive error changed significantly with accommodation when compared to axial refraction particularly in the myopic group. This change in the negative direction was due to changes in the spherical component of refraction that became more myopic relative to the center at the 0.20 m distance as the J0 component of astigmatism was significantly reduced in both emmetropes and myopes for the closest target.

CONCLUSION

Accommodation to very near targets (up to 0.20 m) makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens free emmetropes. A significant reduction in off-axis astigmatism was also observed for the 0.20 m distance.

Evaluation of the MGDRx eyebag treatment in young and older subjects with dry eye symptoms

OBJECTIVES

This study aims to evaluate the relationship between application of the MGDRx thermal eyebag and dry eye signs and symptoms in young and older subjects and to compare the results between the two groups.

METHODS

Thirty young, healthily volunteers between 18 and 31 years of age (23.95±3.94 years) and thirty older subjects between 61 and 90 years of age (77.97±8.11 years) participated in this study. Ocular surface parameters were assessed using the Oculus Keratograph 5M, following the guidelines of the Tear Film and Ocular Surface Dry Eye Workshop II Diagnostic Methodology report. Only subjects with a positive score on at least one questionnaire and an initial Non-Invasive Keratograph Break-Up Time (NIKBUT) under 10seconds were included in the study. After thermal bag self-application in both eyes every day for 2 weeks, the protocol was carried out again. Lid massage was performed after lid warming. Compliance and degree of improvement were also assessed.

MAIN RESULTS

The young volunteer group showed an improvement in NIKBUT, lipid layer score, upper eyelid gland drop-out percentage and dry eye symptoms over the two week treatment period. Improvements in meibum quality, gland obstruction, telangiectasia scores, and dry eye symptoms were found in the older subjects. Mixed ANOVA revealed better NIKBUT and lipid layer values in the young subjects. Despite the treatment compliance being statistically higher in the older group than in the younger subjects (P=0.002), there were no significant differences in subjective improvement between groups (P=0.097).

CONCLUSION

Dry eye-related symptoms were improved after thermal bag application, while NIKBUT and lipid layer thickness were improved only in the younger subjects.

OCT applications in contact lens fitting

Optical Coherence Tomography (OCT) is a noninvasive, high-speed, high-resolution imaging technology based in the Michaelson interferometry. A near-infrared light beam is used to register the intensity variations for the light backscattered on each sample layer. Due to the high repeatability on corneal measurements, spectral domain OCT (SD-OCT) is the gold standard when talking about in vivo, non-invasive anterior segment imaging. Changes in the morphology of various ocular surfaces such as the cornea, conjunctiva, limbus or tear film with soft (SCL), rigid, corneal or scleral lens (SL) wear can be described by OCT measurements. For instance, evaluation of the corneoscleral region is essential on SL fitting. For orthokeratology lenses central epithelial thinning and peripheral thickening and their regression could be quantified with OCT after Ortho-K lens wear. Blood vessel compression on the landing zone as well as vault thickness and fluid reservoir (FR) turbidity could be imaged with OCT. Tear film evaluation on contact lens wearers is essential because its use could lead to variations on the biochemical components in tears. Changes in tear meniscus dynamics and several parameters such as volume (TMV), tear meniscus height (HMT) and turbidity could be determined with OCT and positively correlated with the instillation of different ophthalmic solutions with Non-Invasive Break Up Time (NIBUT) and Schirmer test values. This manuscript shows the increasing applicability of OCT technology for the in vivo characterization of contact lens fitting and interaction with the ocular surface in a faster, safer and non-invasive way. Future research will still allow exploring OCT imaging to its full potential in contact lens practice, as there is still a significant amount of information contained in the images that are not yet easy to extract, analyze and give clinical value.

Systemic, environmental and lifestyle risk factors for dry eye disease in a mediterranean caucasian population

OBJECTIVES

To assess systemic, environmental and lifestyle risk factors for dry eye disease (DED) in a Mediterranean Caucasian population.

METHODS

A cross-sectional study was performed on 120 Caucasian participants aged between 18 and 89 years (47.0 ± 22.8 years). Medical history, information regarding environmental conditions and lifestyle, Ocular Surface Disease Index, Dry Eye Questionnaire-5, non-Invasive (Oculus Keratograph 5 M) breakup time, tear film osmolarity and ocular surface staining parameters were assessed in a single clinical session to allow DED diagnosis based on the guidelines of the Tear Film and Ocular Surface Society Dry Eye Workshop II Diagnostic Methodology Report. A multivariate logistic regression model was constructed including those variables with a p-value less than 0.15 in the univariate analysis.

RESULTS

A prevalence of 57.7 % for DED was found. No age differences were found between those with and without DED (U = 1886.5, p = 0.243). Nevertheless, the DED group had more females (X² = 7.033, p = 0.008). The univariate logistic regression identified as potential risk factors for DED the following: female sex, sleep hours per day, menopause, anxiety, systemic rheumatologic disease, use of anxiolytics, daily medication, ocular surgery, poor diet quality, more ultra-processed food in diet, not drinking caffeine and hours of exposure to air conditioning per day. Multivariate logistic regression revealed that hours of sleep per day, menopause and use of anxiolytics were independently associated with DED (p ≤ 0.026 for all).

CONCLUSIONS

DED is associated with systemic, environmental and lifestyle risk factors. These findings are useful to identify potentially modifiable risk factors, in addition to conventional treatments for DED.

Diagnostic Capability of a New Objective Method to Assess Meibomian Gland Visibility

SIGNIFICANCE

The diagnosis of dry eye disease and meibomian gland dysfunction (MGD) is challenging. Measuring meibomian gland visibility may provide an additional objective method to diagnose MGD.

PURPOSE

This study aimed to evaluate the ability of new metrics to better diagnose MGD, based on measuring meibomian gland visibility.

METHODS

One hundred twelve healthy volunteers (age, 48.3 ± 27.5 years) were enrolled in this study. Ocular surface parameters were measured using the Oculus Keratograph 5M (Oculus GmbH, Wetzlar). Subjects were classified according to the presence or absence of MGD. New metrics based on the visibility of the meibomian glands were calculated and later compared between groups. The diagnostic ability of ocular surface parameters and gland visibility metrics was studied through receiver operating characteristic curves. Logistic regression was used to obtain the combined receiver operating characteristic curve of the metrics with the best diagnostic ability.

RESULTS

Statistically significant differences were found between groups for all ocular surface parameters and new gland visibility metrics, except for the first noninvasive keratograph breakup time and gland expressibility. New gland visibility metrics showed higher sensitivity and specificity than did current single metrics when their diagnostic ability was assessed without any combination. The diagnostic capability increased when gland visibility metrics were incorporated into the logistic regression analysis together with gland dropout percentage, tear meniscus height, dry eye symptoms, and lid margin abnormality score (P < .001). The combination of median pixel intensity of meibography gray values and the aforementioned ocular surface metrics achieved the highest area under the curve (0.99), along with excellent sensitivity (1.00) and specificity (0.93).

CONCLUSIONS

New meibomian gland visibility metrics are more powerful to diagnose MGD than current single metrics and can serve as a complementary tool for supporting the diagnosis of MGD.

Evaluation of Physiological Parameters on Discomfort Glare Thresholds Using LUMIZ 100 Tool

Purpose

To assess the links between discomfort glare sensitivity and physiological factors such as eye biometry, refraction, skin phototype, age, and gender among a large sample of healthy human subjects.

Methods

A total of 489 participants who were 20 to 70 years old (241 men, 248 women) underwent discomfort glare threshold measurements via the LUMIZ 100. Eye biometry and optical quality were measured using a Zeiss IOLMaster 700 biometer and i.Profiler aberrometer. Iris color, skin tone, age, gender, eyeglasses use, chronotype, fatigue level, self-evaluation of light sensitivity, and time spent outdoors were determined. Statistical analysis was carried out using nonparametric Mann-Whitney and Kruskal-Wallis tests for categorical data and correlation coefficients for numerical data.

Results

The female subgroup had lower discomfort thresholds than the males (P < 0.001). There was no effect of age group, ametropia, eye biometry, iris color, skin tones, chronotype, or fatigue level on discomfort thresholds. Discomfort thresholds were related to self-assessment of light sensitivity, sunglasses ownership, and frequency of use (P < 0.001).

Conclusions

Exploration of easily measurable physiological parameters and questionnaire failed to provide reliable indicators of individual light sensitivity to discomfort glare.

Translational Relevance

Light sensitivity is highly subjective and variable across the population. Patients frequently complain about light bothering their daily lives. Accessible physiological factors and questionnaires are unable to predict discomfort levels due to glare. The LUMIZ 100 provides a reliable, rapid, and safe way to determine light discomfort thresholds in order to better manage light sensitivity in clinical care.

Intraoperative Versus Postoperative Vault Measurement After Implantable Collamer Lens Implantation in a Large Cohort of Patients

PURPOSE

To compare intraoperative and postoperative central vault measurement after implantable Collamer lens (ICL; STAAR Surgical) implantation using optical coherence tomography (OCT).

METHODS

A total of 574 eyes of 338 consecutive patients undergoing myopic ICL implantation were evaluated (mean age of 30.8 ± 5.7 years, 117 men and 221 women). Central ICL vault was measured both intraoperatively using the microscope-integrated iOCT (Optomedical Technologies GmbH) mounted on a standard surgical microscope (HS Hi-R NEO 900A; Haag-Streit Surgical GmbH), and postoperatively using the CASIA2 swept-source OCT (Tomey GmbH) at 4 and 24 hours.

RESULTS

Mean differences between intraoperative and postoperative vault values were 11.5 ± 29.0% of the mean value 4 hours postoperatively (P < .001) and 2.7 ± 33.5% of the mean value 24 hours postoperatively (P < .001). Correlation analysis shows significant agreement between vault values obtained intraoperatively and at the two postoperative times, 4 hours (Spearman Rho = 0.850, P < .001) and 24 hours (Spearman Rho = 0.745, P < .001). In 73% of cases, postoperative vault values 4 hours after the surgery could be predicted from intraoperative vault values, and so were 56% of vault values 1 day after surgery. Significant differences in vault were found at the different times, grouping cases by ICL size (Kruskal-Wallis, P = .028 for intraoperative vault, and P < .001 for both postoperative vault times), with smaller vault values for the smaller ICL size.

CONCLUSIONS

Intraoperative determination of ICL vault using iOCT is an effective method for predicting postoperative ICL vault and minimizing postoperative vault surprises that could require surgical retouching. [J Refract Surg. 2021;37(7):477-483.].

Tear film stability over a myopia control contact lens compared to a monofocal design

Clinical relevance: Tear film assessment is essential in contact lens wearers and it can improve the success rates of the fitting.Background: To compare the short-term effect of two contact lenses on pre-lens tear film stability and comfort: dual-focus contact lens (MiSight) and a monofocal contact lens (Proclear 1-day).Methods: This randomised, double-masked, crossover study was performed in twenty-eight healthy, myopic volunteers aged between 18 and 32 years (23.5 ± 4.1 years). Only one randomly chosen eye was assessed. Distance vision and refraction were evaluated at baseline. Each contact lens type (monofocal and dual-focus) was randomly fitted, always in both eyes. A visual analogue scale between 0 and 10 was used to assess general comfort, physical comfort, and visual comfort. Tear Film Surface Quality (TFSQ) index, TFSQ_area and auto Tear Break-Up Time were obtained using Medmont E-300 at baseline (naked eye condition) and 25 minutes after each contact lens insertion.Results: Refractive sphere and cylinder were, respectively, -1.36 ± 1.04 D (ranging from -6.00 to -0.25 D) and -0.23 ± 0.30 D (ranging from -0.75 to 0.00 D). TFSQ and TFSQ area were lower (meaning more stable tear film) at baseline when compared with both contact lens types (p < 0.025). Higher pre-lens tear instability (larger TFSQ and_TFSQ area values) was found with the dual-focus than the monofocal lens. Auto Tear Break-Up Time was higher at baseline than with each of the contact lenses, without statistically significant differences between both contact lens types. Visual analogue scales revealed statistically significant better scores in the monofocal contact lens than in dual-focus contact lens for general (0.77 ± 1.14 vs 3.12 ± 2.79), physical (0.96 ± 1.46 vs 2.19 ± 2.45) and visual comfort (1.27 ± 1.66 vs 3.92 ± 2.04).Conclusion: A slight reduction in short-term pre-lens tear film stability was found in the dual-focus design in comparison with the monofocal lens, potentially contributing to the deterioration of visual performance and comfort during dual-focus contact lens wear.

An Emerging Method to Assess Tear Film Spread and Dynamics as Possible Tear Film Homeostasis Markers

Purpose: This study aims to assess the performance of an analysis method to measure in vivo the movement speed of tear film particles post-blink as a measure of tear film spreading.Materials and methods: Ocular surface parameters and the recording of tear film particles' spreading post-blink were assessed in eighty-one healthy volunteers (43.7 ± 27.0 years) using Keratograph 5 M. The developed software automatically decomposed the video into frames to manually track particles' position for 1.75 seconds after a blink. The following tear film-dynamic metrics were automatically calculated: mean, median, maximum, and minimum particles' speed at different times after blinking and time for particle speed to decrease to <1.20 mm/second. Repeatability of each tear film-dynamic metric and its correlations with ocular surface signs and symptoms were analyzed. Binomial logistic regression was performed to assess the predictability of new metrics to ocular parameters.Results: Repeatability tended to be lower just after blinking (variability of 12.24%), whereas the metrics from 0.5 s onwards had acceptable repeatability (variability below 10%). Tear film-dynamic metrics correlated positively with Non-Invasive Break-Up Time (NIKBUT) while negatively with meibomian gland drop-out. Binomial logistic regression analysis revealed that tear film-dynamic metrics were able to predict NIKBUT. Nevertheless, no statistically significant association was found with gland drop-out. This means that higher particle speed is related to larger NIKBUT. The metric "time for particle speed to decrease to <1.20 mm/second" can be considered the best metric to assess the quality of the tear film, since it was more strongly correlated with NIKBUT (r = 0.42, p = .004), it was more strongly associated in the binomial logistic regression analysis with NIKBUT and showed good repeatability (variability = 5.49%).Conclusions: Tear film-dynamic metrics are emerging homeostasis parameters for assessing indirectly the tear film quality in natural conditions with acceptable repeatability.

Meibomian glands visibility assessment through a new quantitative method

PURPOSE

The aim of this study is to develop a new objective semiautomatic method for analysing Meibomian glands visibility quantitatively.

METHODS

One hundred twelve healthy volunteers aged between 18 and 90 years (48.29 ± 27.46 years) participated in this study. Infrared meibography was obtained from the right upper eyelid through Oculus Keratograph 5 M. Meibographies were classified into 3 groups: Group 1 = patients with good subjective glands visibility and a gland dropout percentage < 1/3 of the total Meibomian gland area; Group 2 = patients with low subjective glands visibility and a gland dropout < 1/3; and Group 3 = patients with low subjective glands visibility and a gland dropout > 1/3. New metrics based on the visibility of the Meibomian glands were calculated and later compared between groups. Rho Spearman test was used to assess the correlation between each metric, and Meibomian gland dropout percentage with the entire sample and after excluding Group 2. A p value less than 0.05 was defined as statistically significant.

RESULTS

Fifty-six subjects were classified in Group 1 (24.48 ± 9.62 years), 19 in Group 2 (69.16 ± 21.30 years) and 37 in Group 3 (73.59 ± 13.70 years). No statistically significant differences were found between Groups 1 and 2 in dropout percentage. All metrics, with the exception of entropy, showed a higher Meibomian gland visibility in Group 1 than in the other two groups. Moderate correlations were statistically significant for all metrics with the exception of entropy. Correlations were higher after excluding Group 2.

CONCLUSION

The proposed method is able to assess Meibomian gland visibility in an objective and repeatable way, which might help clinicians enhance Meibomian gland dysfunction diagnosis and follow-up treatment.

Performance of a new device for the clinical determination of light discomfort

PURPOSE

To assess the performance of a new device for the clinical determination of light discomfort on a large sample of healthy human subjects.

METHODS

A total of 489 subjects ranging from 20 to 70 years old (241 men, 248 women) were evaluated with the LUMIZ™ 100 to determine light discomfort. Repeatability was assessed by means of within-subject standard deviation, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Repeated measures ANOVA, Kruskal-Wallis, and correlation analysis were applied to test for differences between repeated measures, and effect of age on reliability.

RESULTS

Discomfort thresholds obtained are well distributed across the light intensity range available (25 to 10211 lux). Intrasession ICCs are higher than 0.849 for all thresholds, and 85% of CoV are below 10%. Thresholds obtained in the first set of measurements are highly correlated with the median of three sets (r2 > 0.8). Intersession, 64% of CoV are below 10%. Age does not affect discomfort thresholds (p = 0.30), nor affect reliability (variance on CoV, p = 0.368).

CONCLUSIONS

The new device provides good intrasession repeatability for the clinical determination of light discomfort thresholds, although variance is slightly greater between sessions. The system is useful for the clinical determination of light discomfort.

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

PURPOSE

To study the light distortion effects of soft multifocal contact lenses and the influence of different pupil size and shape.

METHODS

A 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.

RESULTS

The 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.

CONCLUSIONS

The 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.

Spotlight on fundus autofluorescence

Fundus autofluorescence (FAF) imaging is based on the fluorescence from ocular endogenous fluorophores located in the retinal pigment epithelium and choroid, mainly lipofuscin and melanin. It is a noninvasive technique that provides information about the spatial distribution of lipofuscin/melanin and retinal pigment epithelium health status. An overview about the fluorophores responsible for FAF imaging and the usefulness of FAF imaging in the noninvasive assessment and monitoring of retinal diseases, such as age-related macular degeneration, diabetic retinopathy, diabetic macular edema, central serous chorioretinopthy, retinitis pigmentosa and retinal dystrophies, are discussed in this review.

Confocal scanning laser ophthalmoscopy versus modified conventional fundus camera for fundus autofluorescence

INTRODUCTION

Fundus autofluorescence (FAF) is a noninvasive imaging method to detect fundus endogenous fluorophores, mainly lipofuscin located in the retinal pigment epithelium (RPE). The FAF provides information about lipofuscin distribution and RPE health, and consequently an increased accumulation of lipofuscin has been correlated with ageing and development of certain retinal conditions. Areas covered: An exhaustive literature search in MEDLINE (via OVID) and PUBMED for articles related to ocular FAF in retinal diseases and different devices used for acquiring FAF imaging was conducted. Expert commentary: This review aims to show an overview about autofluorescence in the RPE and the main devices used for acquiring these FAF images. The knowledge of differences in the optical principles, acquisition images and the image post-processing between confocal scanning laser ophthalmoscopy and modified conventional fundus camera will improve the FAF images interpretation when are used as a complementary diagnosis and monitoring tool of retinal diseases.

Ocular autofluorescence in diabetes mellitus. A review

Diabetes mellitus is a metabolic disease with a considerable impact on healthcare owing to its increased prevalence and high mortality rate. Structural, morphological, and physiological changes in each of the ocular components have been described in detail. Autofluorescence has been described as a good indicator of metabolic activity. The aim of the present review is to provide an overview of ocular endogenous fluorophores in the cornea, the crystalline lens, and the retinal pigment epithelium, the effects of diabetes mellitus and therefore the potential of autofluorescence assessment for screening and monitoring changes in diabetic patients.

Evaluation of the anterior chamber angle in keratoconus and normal subjects

PURPOSE

To evaluate the anterior chamber angle in keratoconus eyes by use of the Visante™ OCT and Orbscan™ II.

METHODS

Anterior chamber angle was measured with the Visante™ OCT and Orbscan™ II in 52 subjects, 26 KC subjects and 26 age and control subjects.

RESULTS

When comparing the nasal and temporal angles obtained with the two techniques no correlation was found (R(2) always below 0.01) in either the control subjects or in the KC subjects. Despite this, there was an overall statistically significant difference in mean anterior chamber angles (p<0.001) between Visante™ OCT and Orbscan™ II. There was no statistical difference (p>0.05) between nasal and temporal anterior chamber angles when comparing controls and KC subjects with either of the two instruments. In general, the Visante™ OCT gave a smaller estimate of the anterior chamber angle.

CONCLUSION

The values from the Visante™ OCT and Orbscan™ II cannot be interchanged since the difference in measurement of the anterior chamber angle was significantly different between the two instruments.

Optical quality of the diabetic eye: a review

Diabetes mellitus is a metabolic disorder characterized by the presence of chronic hyperglycaemia. Several structural, morphological, and physiological changes in each of ocular component have been described in detail during the past decades. Due to these abnormalities, the diabetic patient undergoes a degradation of the retinal image by an increase of higher ocular aberrations and ocular scattering coming from mainly tear film, cornea, and crystalline lens. This review aims to provide an overview of current knowledge about the effects of diabetes mellitus in these optical phenomena and its consequence on the visual quality of the diabetic patient.

Preliminary in vivo positional analysis of a posterior chamber phakic intraocular lens by optical coherence tomography and its correlation with clinical outcomes

Purpose

To analyze by spectral-domain optical coherence tomography the anatomical relationship of a specific type of posterior chamber phakic intraocular lens (pIOL) implanted in cases of high to moderate myopia with the adjacent intraocular structures and to correlate it with clinical outcomes.

Methods

Prospective observational case series including 18 eyes with high to moderate myopia (spherical equivalent between −5.88 and −15.75 D) of 9 patients (age range, 29–49 years) undergoing bilateral Phakic Refractive Lens (PRL, Zeiss) implantation. Postoperative visual acuity, refraction, contrast sensitivity (CS), and ocular higher order aberrations (HOA) were evaluated. Furthermore, the in vivo position of the PRL was analyzed by means of spectral domain optical coherence tomography (3D OCT-1000, Topcon). Central (CENV), temporal (TEMV) and nasal vault (NASV) were measured. Correlation of these anatomical parameters with clinical data was also investigated. Mean follow-up was 47 ± 25 months.

Results

A statistically significant visual and refractive improvement (p < 0.01) was found postoperatively. Mean postoperative CENV, NASV, and TEMV were 157.88 ± 69.93 μm, 168.29 ± 65.02 μm, and 188.59 ± 55.99 μm, respectively. Significant difference was found between NASV and TEMV (p = 0.01). No significant correlations were found between ocular aberrometric and anatomical parameters (p ≥ 0.12). CENV, NASV and TEMV correlated significantly with 6-cycles per degree (cpd) photopic CS as well as with 18-cpd low mesopic CS (r ≥ 0.57, p ≤ 0.04). Furthermore, NASV also correlated significantly with preoperative anterior chamber depth (r = −0.65, p = 0.01).

Conclusions

This posterior chamber pIOL shows a trend to nasal position, with potential impact on refractive and visual outcomes, particularly in eyes with deep anterior chambers.

Visual function through 4 contact lens-based pinhole systems for presbyopia

PURPOSE

To evaluate the effects of different contact lens-based artificial pupil designs on visual performance.

SETTING

University of Valencia, Burjassot, Spain, and University of Manchester, Manchester, United Kingdom.

DESIGN

Comparative case series.

METHODS

Presbyopic patients were evaluated using 4 artificial pupil designs in the nondominant eye. Binocular uncorrected distance visual acuity (UDVA), binocular corrected distance visual acuity (CDVA), binocular uncorrected near visual acuity (UNVA), binocular distance-corrected near visual acuity (DCNVA), defocus curve, binocular distance, and near contrast sensitivity under photopic and mesopic conditions, and stereoacuity were measured after contact lens fitting.

RESULTS

The mean UDVA and CDVA ranged from 0.04 ± 0.05 (SD) to -0.01 ± 0.04 logMAR and from -0.02 ± 0.05 to -0.05 ± 0.03 logMAR, respectively. The UNVA and DCNVA ranged from 0.37 ± 0.11 to 0.42 ± 0.20 logMAR and from 0.35 ± 0.17 to 0.38 ± 0.12 logMAR, respectively. The difference in binocular distance contrast sensitivity was statistically significant between the pinhole systems and the control group (distance-corrected patients without pinhole lens) for 6 cycles per degree (cpd), 12 cpd, and 18 cpd; for near vision, differences were also significant for 3 cpd at the 2 luminance levels (P<.05). Stereoacuity values for near vision were not significantly different between the 4 pinhole systems (P>.05).

CONCLUSIONS

Soft contact lens apertures provide good visual acuity at distance, functional intermediate vision, and poor near visual acuity and stereoacuity. An improvement in visual performance with decreasing pupil diameter was not found.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Medium-term visual, refractive, and intraocular stability after implantation of a posterior chamber phakic intraocular lens to correct moderate to high myopia

PURPOSE

To evaluate the medium-term refractive and visual outcomes and the complications after implantation of a silicone posterior chamber phakic intraocular lens (PC pIOL) for moderate to high myopia.

SETTING

Oftalmar, Medimar International Hospital, Alicante, Spain.

DESIGN

Retrospective case series.

METHODS

Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, and intraocular pressure were evaluated during a medium-term follow-up. Postoperative complications were also studied.

RESULTS

The study enrolled 35 eyes (mean preoperative spherical equivalent [SE] -10.25 diopters [D] ± 3.19 [SD]) of 20 patients with a mean age of 31.83 ± 8.87 years and a mean follow-up of 57.34 ± 9.24 months. The mean UDVA improved from 2.40 ± 0.20 logMAR preoperatively to 0.08 ± 0.13 logMAR at the last postoperative visit (P<.01). The mean CDVA improved from 0.11 ± 0.09 logMAR to 0.02 ± 0.09 logMAR, respectively (P<.01). The postoperative CDVA was 0.1 or better in 30 eyes (85.71%), with 22 eyes (62.86%) gaining lines of CDVA. The final efficacy index was 1.16 and the final safety index, 1.26. Regarding predictability, 34 eyes (97.14%) had an SE within ± 1.00 D and 33 eyes (94.28%) within ± 0.50 D. The complications were PC pIOL decentration (2 eyes, 5.71%), cortical lens opacification (1 eye, 2.86%), and retinal detachment (1 eye, 2.86%).

CONCLUSIONS

Implantation of a PC pIOL to correct moderate to high myopia was efficient and predictable in the medium term, with intraocular stability in most cases. New designs and criteria for PC pIOL size selection should be developed.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Visual performance with simultaneous vision multifocal contact lenses

PURPOSE

  The aim was to assess visual performance after PureVision high addition multifocal contact lens (PM) fitting through contrast sensitivity measured under different illumination levels for both distance and near.

METHODS

  In a cross-over study, 20 presbyopic patients were randomly assigned to PM or spectacles. Near contrast sensitivity was measured with the Vistech VCTS 6500 system. Distance contrast sensitivity and distance visual acuity (VA) were measured with the Functional Vision Analyser under photopic (85 cd/m(2) ) and mesopic (3.0 cd/m(2) ) conditions, the latter also under two levels of induced glare: 1.0 lux and 28 lux. Near VA was measured by logMAR charts under approximately 80 cd/m(2) luminance settings.

RESULTS

  Average monocular spectacle corrected and PM VA were -0.02 ± 0.05 and 0.03 ± 0.05 logMAR for distance photopic, 0.16 ± 0.10 and 0.23 ± 0.07 logMAR for distance mesopic and -0.03 ± 0.05 and 0.05 ± 0.06 logMAR for near photopic, respectively. Average binocular spectacle corrected and PM VA were -0.05 ± 0.07 and -0.01 ± 0.03 logMAR for distance photopic, 0.10 ± 0.06 and 0.18 ± 0.05 logMAR for distance mesopic and -0.08 ± 0.06 and 0.02 ± 0.05 logMAR for near photopic, respectively. Statistically significant differences were found between the contrast sensitivity with the two types of correction for both distance and near, with spectacle correction being better in all cases.

CONCLUSION

  PureVision multifocal contact lenses preserve good VA and good visual performance under real-life conditions.

Visual and optical performance with hybrid multifocal intraocular lenses

During the past years, the wish to become independent of spectacles has been growing among cataract and presbyopic patients due to many factors, such as the increase in near visual demands, the aesthetic need for a spectacle-free image and ageing of refractive surgery patients, among others. This review assesses recently published studies that analyse visual and optical performance through different metrics of eyes implanted with multifocal intraocular lenses (IOLs), particularly hybrid IOL designs. The published evidence suggests that hybrid multifocal IOLs provide very good outcomes in a number of visual and optical performance parameters. Patients implanted with this type of IOL obtain a satisfactory full range of visual functions, including patients of particular characteristics such as highly ametropic or post-LASIK.