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PURPOSE: To investigate whether the midday removal and re-application of scleral lenses (SL) influences fluid reservoir (FR) thickness, pre-lens tear film quality and visual acuity. METHODS: Two clinical experiments were conducted. A total of 49 keratoconic eyes were evaluated for Part1(tear film and visual acuity analysis) and 12 keratoconic eyes for Part2 (FR thickness analysis). All subjects were wearing 16.4 mm SL for more than 12-months. Tear Film Surface Quality (TFSQ) was evaluated with Medmont E300 at more than 120 min of SL wear, 10 min after SL removal (pre-corneal TFSQ) and 5 min after re-apply the same SL. High and Low Contrast Visual Acuity (HCVA and LCVA) were also assessed with the SL on eye (before and after re-application). For Part2, Anterior OCT (MOptim MOcean4000, China) measurements were taken with and without the SL (at the same time points of Part1) and three outcomes were evaluated: FR thickness, SL thickness (control measurement) and corneal thickness. RESULTS: Removing and re-applying a SL had a statistically significant positive impact on TFSQ, with an improvement from 0.26 ± 011 to 0.16 ± 0.08 (p = 0.001). This was accompanied by a statistically significant improvement in LogMAR HCVA (from 0.10 ± 0.09 to 0.08 ± 0.08, p < 0.001) and LCVA (from 0.39 ± 0.13 to 0.36 ± 0.13, p < 0.001). Regarding Part2 of the study, a statistically significant increase in FR thickness was observed after SL re-application (from 223.64 ± 48.08 µm to 267.81 ± 80.03 µm, p = 0.007). No changes in corneal thickness were observed. CONCLUSIONS: Midday removal and re-application of a scleral lens positively impacted pre-lens tear film surface quality, although the observed improvement in visual acuity does not constitute a clinically significant change. Clinicians should consider that removing and reapplying a scleral lens may result in an overestimation of the fluid reservoir thickness, which could affect clinical assessments and treatment decisions.
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BACKGROUND: Myopia management contact lenses have been shown to successfully decrease the rate of eye elongation in children by changing the peripheral refractive profile of the retina. Despite the efforts of the scientific community, the retinal response mechanism to defocus is still unknown. The purpose of this study was to evaluate the local electrophysiological response of the retina with a myopia control contact lens (CL) compared to a single-vision CL of the same material. METHODS: The retinal electrical activity and peripheral refraction of 16 eyes (16 subjects, 27.5 ± 5.7 years, 13 females and 3 males) with myopia between -0.75 D and -6.00 D (astigmatism < 1.00 D) were assessed with two CLs (Filcon 5B): a single-vision (SV) CL and an extended-depth-of-focus (EDOF) CL used for myopia management. The peripheral refraction was assessed with an open-field WAM-5500 auto-refractometer/keratometer in four meridians separated by 45° at 2.50 m distance. The global-flash multifocal electroretinogram (gf-mfERG) was recorded with the Reti-port/scan21 (Roland Consult) using a stimulus of 61 hexagons. The implicit time (in milliseconds) and response density (RD, in nV/deg2) of the direct (DC) and induced (IC) components were used for comparison between lenses in physiological pupil conditions. RESULTS: Although the EDOF decreased both the HCVA and the LCVA (one and two lines, respectively; p < 0.003), it still allowed a good VA. The EDOF lens induced a myopic shift in most retinal areas, with a higher and statistically significant effect on the nasal retina. No differences in the implicit times of the DC and IC components were observed between SV and EDOF. Compared with the SV, the EDOF lens showed a higher RD in the IC component in the foveal region (p = 0.032). In the remaining retinal areas, the EDOF evoked lower, non-statistically significant RD in both the DC and IC components. CONCLUSIONS: The EDOF myopia control CL enhanced the response of the inner layers of the fovea. This might suggest that, besides other mechanisms potentially involved, the central foveal retinal activity might be involved in the mechanism of myopia control with these lenses.
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PURPOSE: To evaluate the influence of defocus and pupil size on subjective (visual acuity [VA]) and objective (electrophysiology) descriptors of human vision and their effect on binocular visual performance by means of neural binocular summation (BS). METHODS: Fifteen healthy young subjects were recruited in this crossover study. Pattern electroretinogram (PERG) and visual evoked potentials (VEP) were measured under two levels of positive (+1.5 and +3.0 D) spherical and astigmatic defocus (axis 90°). Pupil size was controlled to reduce the inter-individual variability factor. RESULTS: Low- and high-contrast VA showed poorer visual performance in the monocular versus the binocular condition. Positive BS (for VA) was higher with greater pupil size and higher levels of defocus. In the visual electrophysiology tests (i.e., VEP and PERG), peak time and amplitude were affected by pupil size and defocus. The increase in peak time was larger and the reduction in amplitude was more significant with greater levels of defocus and smaller pupil sizes. For the VEP, positive BS was found in all conditions, being stronger with larger amounts of defocus and pupil size (for the P100 amplitude). Significant negative correlations were observed between the P100 amplitude and VA BSs. CONCLUSION: Smaller pupil size and levels of defocus produced greater changes in cortical activity as evidenced by both the PERG and VEP. Considering these changes and the obtained positive BS, the mechanism could be initiated as early as the retinal processing stage, then being modulated and enhanced along the visual pathway and within the visual cortex.
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PURPOSE: The axial elongation in myopia is associated with some structural and functional retinal changes. The purpose of this study was to investigate the effect of a contact lens (CL) intended for myopia control on the choroidal thickness (ChT) and the retinal electrical response. METHODS: Ten myopic eyes (10 subjects, 18-35 years of age) with spherical equivalents from -0.75 to -6.00 diopters (D) were enrolled. The ChT at different eccentricities (3 mm temporal, 1.5 mm temporal, sub-foveal ChT, 1.5 mm nasal, and 3 mm nasal), the photopic 3.0 b-wave of ffERG and the PERG were recorded and compared with two material-matched contact lenses following 30 min of wear: a single-vision CL (SV) and a radial power gradient CL with +1.50 D addition (PG). RESULTS: Compared with the SV, the PG increased the ChT at all eccentricities, with statistically significant differences at 3.0 mm temporal (10.30 ± 11.51 µm, p = 0.020), in sub-foveal ChT (17.00 ± 20.01 µm, p = 0.025), and at 1.5 mm nasal (10.70 ± 14.50 µm, p = 0.044). The PG decreased significantly the SV amplitude of the ffERG photopic b-wave (11.80 (30.55) µV, p = 0.047), N35-P50 (0.90 (0.96) µV, p = 0.017), and P50-N95 (0.46 (2.50) µV, p = 0.047). The amplitude of the a-wave was negatively correlated with the ChT at 3.0T (r = -0.606, p = 0.038) and 1.5T (r = -0.748, p = 0.013), and the amplitude of the b-wave showed a negative correlation with the ChT at 1.5T (r = -0.693, p = 0.026). CONCLUSIONS: The PG increased the ChT in a similar magnitude observed in previous studies. These CLs attenuated the amplitude of the retinal response, possibly due to the combined effect of the induced peripheral defocus high-order aberrations impacting the central retinal image. The decrease in the response of bipolar and ganglion cells suggests a potential retrograde feedback signaling effect from the inner to outer retinal layers observed in previous studies.
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This study aimed to evaluate the peripheral defocus induced with a novel perifocal ophthalmic lens for myopia progression control and the potential impact on visual function. This experimental, non-dispensing crossover study evaluated 17 myopic young adults. The peripheral refraction was measured using an open-field autorefractor, at 2.50 m from the target point, in two eccentric points, 25° temporal, 25° nasal, and central vision. Visual contrast sensitivity (VCS) was measured at 3.00 m with a Vistech system VCTS 6500 in low light conditions. Light disturbance (LD) was assessed with a light distortion analyzer 2.00 m away from the device. Peripheral refraction, VCS, and LD were assessed with a monofocal lens and perifocal lens (with an add power of +2.50 D on the temporal side of the lens, and +2.00 D on the nasal side). The results showed that the perifocal lenses induced an average myopic defocus of -0.42 ± 0.38 D (p-value < 0.001) in the nasal retina, at 25° The changes induced by the lower add power in the nasal part of the lens did not induce statistically significant changes in the refraction of the temporal retina. The VCS and LD showed no significant differences between the monofocal and perifocal lenses.
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PURPOSE: Smaller pupil size under binocular conditions could justify partially the improvement of visual performance when compared to monocular conditions. The purpose of this study was to assess the binocular summation for increasing levels of spherical and cylindrical defocus when the pupil size factor is ruled out as a confounding factor. METHODS: Fifteen young subjects were recruited in this crossover study. Light disturbance index (LDI) was evaluated with the light disturbance analyzer and low (LCDVA) and high (HCDVA) contrast visual acuity with the ETDRS test. Two positive spherical and cylindrical defocus levels (+ 1.5 and + 3.0 D) were used to induce a controlled degradation of the retinal image for two pupil sizes (3 and 5 mm). RESULTS: Our results showed poorer visual performance in monocular than the binocular condition. An increasing deterioration was observed with the level of spherical defocus. Positive binocular summation for visual acuity was found in all the parameters studied and was stronger under larger pupil size and for higher levels of spherical defocus. It was observed a positive binocular summation for the LDI under all the conditions studied. Strong and significant correlations were found between LDI and LCDVA and between LDI and HCDVA for all the conditions. Higher correlations were obtained between disturbance index and visual acuity for spherical defocus compared to cylindrical. CONCLUSION: Binocular summation was observed under different conditions of spherical and cylindrical optical degradation of the image quality when the pupil size was fully controlled. This suggests that a neural factor is involved.
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Pupila , Visão Binocular , Humanos , Estudos Cross-Over , Visão Monocular , Acuidade VisualRESUMO
This study aims to evaluate the existing mathematical approach for the theoretical estimation of axial length (AL) in a cross-sectional study, developing a new mathematical model and testing it in a longitudinal sample. Many professionals do not have a device to measure the AL due to clinic space and cost of equipment. However, this parameter plays an important role in the assessment of myopia progression to monitor treatment effects with myopia control strategies. First, a cross-sectional study based on the mathematical equation proposed by Morgan was performed. The AL was estimated based on the mean values of keratometry and spherical equivalent in 1783 subjects (52% female), aged 14.6 ± 4.6 years (6 to 25 years), of whom 738 were myopic, 770 emmetropic and 275 hyperopic. On average, the AL estimated with the Morgan formula was 0.25 ± 0.48 mm larger than the real AL value (95% limits of agreement: +0.70 to −1.20 mm). The study by gender, ametropia, type of astigmatism and age showed statistically significant differences between the real AL and predicted AL_Morgan (r > 0.750, spearman). Based on the previous sample, a multiple linear regression was applied, and a new mathematical model was proposed. The model was tested on a longitudinal sample of 152 subjects whose mean age was 13.3 ± 3.1 years (9 to 24 years) and of whom 96 were female (64%). The sample consisted of 46 myopes, 82 emmetropes and 24 hyperopes. The longitudinal study of the differences in axial length at one year between the models showed no statistically significant differences and that the mathematical equations are valid for estimating differences in axial increment for ages between 9 and 24 years, despite errors in the predicted value for axial length.
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INTRODUCTION: Multifocal simultaneous imaging challenges the visual system to process the multiple overlaps of focused and defocused images. Retinal image processing may be an important step in neuroadaptation to multifocal optical images. Our aims are, firstly to evaluate the short-term effect of different multifocal contact lenses (MF) on retinal activity in young healthy subjects (Experiment#1) and secondly, to evaluate any changes in retinal activity in presbyopic patients fitted with MF over a 15-day period (Experiment#2). METHODS: In Experiment-#1, 10 emmetropic healthy young subjects were included to evaluate the short-term effect of different MFs designs. In Experiment #2, 4 presbyopic subjects were included to wear MF for 15 days. Following the ISCEV Standards, multifocal electroretinograms (mfERGs) were recorded to evaluate different retinal regions under different conditions: with single vision contact lens (SVCL) and with center-distance and center-near MF. RESULTS: In Exp#1 the peak time of N1, P1 and N2 were found to be delayed with the MF (p ≤ 0.040). There was a significant reduction for N1 amplitude in all retinal regions (p < 0.001), while for P1 and N2 amplitudes this reduction was more significant in the peripheral regions (p < 0.005, ring 5 to 6). With center-near MF the mean response density (nV/deg2) showed a significant decrease in all wave components of the mfERGs response, particularly from Ring 3 to Ring 6 (p < 0.001, all Rings). In Exp#2, the mean mfERG response is similar between SVCL and center-distance MF, while center-near MF showed an increase in implicit time N1 and P1 on day 1 that tends to recover to baseline values after 15 days of MF wear. CONCLUSIONS: significant changes in the mfERGs responses were found with the MF lens, being most noticeable with the center-near MF lens design. The present results suggest that the observed delay in cortical response described during the adaptation to multifocality may partially begin at the retina level.
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Lentes de Contato , Eletrorretinografia , Eletrorretinografia/métodos , Humanos , Retina/fisiologiaRESUMO
Altered retinal dopamine and ON-pathway activity may underlie myopia development. It has been shown that the stimulation of the blind spot with short-wavelength light increases the electroretinogram (ERG) b-wave amplitude of myopic eyes and may engage the retinal dopaminergic system. This study evaluated the impact of various durations of blind spot stimulation on the electrophysiological response of the myopic retina and their relationship to axial length. Six myopic individuals underwent three short-wavelength blue light blind spot stimulation protocols (10 s, 1 min, 10 min) using a virtual reality headset. As a control condition, no stimulation was shown for 1 min. The b-wave amplitude of the photopic full-field ERG was measured at baseline and 10, 20, 30, 40, 50, and 60 min after each condition. A significant increase in b-wave amplitude was observed for all stimulation protocols compared to the control. The peak b-wave amplitude was observed 20 min after the 1-min stimulation protocol and 60 min after the 10-min stimulation protocol. A significant positive correlation was found between axial length of the eye and percent change in b-wave amplitude for the 10-min stimulation protocol. A rapid and a delayed b-wave time course responses were observed following 1 min and 10 min of blind spot stimulation, respectively. Overall, these results indicate that light stimulation of the blind spot for various durations elevates ON-bipolar cell activity in the retina and as such is assumed to reduce the myopic response. These findings could have implications for future myopia treatment.
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Visão de Cores , Miopia , Eletrorretinografia/métodos , Humanos , Luz , Miopia/terapia , Estimulação Luminosa/métodos , Retina/fisiologiaRESUMO
Upregulation of retinal dopaminergic activity may be a target treatment for myopia progression. This study aimed to explore the viability of inducing changes in retinal electrical activity with short-wavelength light targeting melanopsin-expressing retinal ganglion cells (ipRGCs) passing through the optic nerve head. Fifteen healthy non-myopic or myopic young adults were recruited and underwent stimulation with blue light using a virtual reality headset device. Amplitudes and implicit times from photopic 3.0 b-wave and pattern electroretinogram (PERG) were measured at baseline and 10 and 20 min after stimulation. Relative changes were compared between non-myopes and myopes. The ERG b-wave amplitude was significantly larger 20 min after blind-spot stimulation compared to baseline (p < 0.001) and 10 min (p < 0.001) post-stimulation. PERG amplitude P50-N95 also showed a significant main effect for 'Time after stimulation' (p < 0.050). Implicit times showed no differences following blind-spot stimulation. PERG and b-wave changes after blind-spot stimulation were stronger in myopes than non-myopes. It is possible to induce significant changes in retinal electrical activity by stimulating ipRGCs axons at the optic nerve head with blue light. The results suggest that the changes in retinal electrical activity are located at the inner plexiform layer and are likely to involve the dopaminergic system.
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Eletrorretinografia/métodos , Potenciais Evocados Visuais , Miopia/fisiopatologia , Células Ganglionares da Retina/patologia , Adolescente , Adulto , Estudos de Casos e Controles , Humanos , Refração Ocular , Acuidade Visual , Adulto JovemRESUMO
Purpose: To investigate changes in the multifocal electroretinogram (mfERG) response in eyes with keratoconus when corrected with scleral lenses (SL) compared with the best correction in glasses.Methods: The mfERG responses in 10 eyes with keratoconus were recorded with the best correction using both a trial frame (baseline) and a hexafocon A SL using an electrophysiological diagnostic system. Electrophysiologic measurements were performed with the pupils fully dilated with instillation of 1% phenylephrine. The implicit time (milliseconds), amplitude (nV), and response density (nV/deg2) of the peaks (N1, P1, and N2) were analyzed for the total mfERG response, six rings and four quadrants of the retina, and compared between the two conditions.Results: All eyes had a significant improvement in visual quality with the SL compared with baseline (mean differences, 0.26 ± 0.17 and 0.22 ± 0.13 logarithm of the minimum angle of resolution for high- and low-contrast visual acuity, respectively). The peaks implicit times of the mfERG responses did not show significant differences (p > .05). The P1 amplitude decreased in all the retinal areas with the SL. Only the total retinal response and the nasal quadrants reached significance (p ≤ 0.044). The P1 response density in ring 1 was on average higher with the SL, but not significantly so. The decline in P1 response density from the center to the periphery was more abrupt with the SL, and was more similar to the response density distribution of a typical subject, without a corneal pathology.Conclusions: mfERG did not show any change associated with retinal disease in young patients with keratoconus. Although the improved visual performance was not associated with changes in the mfERG response, the correction of irregular astigmatism with the SL helps exclude the optical effect induced by keratoconus.
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Lentes de Contato , Ceratocone/terapia , Retina/fisiopatologia , Esclera , Adulto , Estudos Cross-Over , Eletrorretinografia , Óculos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Acuidade Visual/fisiologiaRESUMO
This study aimed to evaluate the effects of two months of orthokeratology (OK) treatment in the accommodative response of young adult myopes. Twenty eyes (21.8 ± 1.8 years) were fitted with the Paragon CRT® 100 LENS to treat myopia between -1.00 and -2.00 D. Low- and high-contrast visual acuity (LCDVA and HCDVA), central objective refraction, light disturbance (LD), and objective accommodative response (using the Grand Seiko WAM-5500 open-field autorefractometer coupled with a Badal system) were measured at baseline (BL) before lens wear and after 1, 15, 30, and 60 nights of OK. Refractive error correction was achieved during the first fifty days of OK lens wear, with minimal changes afterwards. LD analysis showed a transient increase followed by a reduction to baseline levels over the first 30 nights of treatment. The accommodative response was lower than expected for all target vergences in all visits (BL: 0.61 D at 1.00 D to 0.96 D at 5.00 D; 60 N: 0.36 D at 1.00 D to 0.79 D at 5.00 D). On average, the accommodative lag decreases over time with OK lens wear. However, these differences were not statistically significant (p > 0.050, repeated-measures ANOVA and Friedman test). This shows that overnight OK treatment does not affect objectively measured the accommodative response of young, low myopic eyes after two months of treatment stabilization.
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The aim of this study was to evaluate the changes in retinal activity during orthokeratology (OK) treatment in 20 myopic eyes. Pattern electroretinography (PERG) and visual evoked potential (VEP) were assessed with the RETI-port/scan21 (Roland Consult, Wiesbaden, Germany). Measurements were taken at baseline (BL) and 1 night (1N), 15 nights (15N), 30 nights (30N), and 60 nights (60N) of OK lens wear. Repeated measures analysis of variance (ANOVA) and the Friedman test were used. Twenty eyes (23.20 ± 3.46 years, 70% female) with visual acuity ≤ 0.00 logMAR in post-treatment showed that despite a slight increase in retinal and cortical response amplitude, observed with both PERG and VEP, respectively, immediately after the initial treatment, these differences found were not statistically significant during the 60 days of OK treatment, despite a statistically significant increase in N95 response with PERG. This shows that retinal and cortical visual-related electrical activity is maintained or slightly increased during OK treatment.
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Bifocal and multifocal optical devices are intended to get images into focus from objects placed at different distances from the observer. Spectacles, contact lenses, and intraocular lenses can meet the requirements to provide such a solution. Contact lenses provide unique characteristics as a platform for implementing bifocality and multifocality. Compared to spectacles, they are closer to the eye, providing a wider field of view, less distortion, and their use is more consistent as they are not so easily removed along the day. In addition, contact lenses are also minimally invasive, can be easily exchangeable, and, therefore, suitable for conditions in which surgical procedures are not indicated. Contact lenses can remain centered with the eye despite eye movements, providing the possibility for simultaneous imaging from different object distances. The main current indications for bifocal and multifocal contact lenses include presbyopia correction in adult population and myopia control in children. Considering the large numbers of potential candidates for optical correction of presbyopia and the demographic trends in myopia, the potential impact of contact lenses for presbyopia and myopia applications is undoubtedly tremendous. However, the ocular characteristics and expectations vary significantly between young and older candidates and impose different challenges in fitting bifocal and multifocal contact lenses for the correction of presbyopia and myopia control. This review presents the recent developments in material platforms, optical designs, simulated visual performance, and the clinical performance assessment of bifocal and multifocal contact lenses for presbyopia correction and/or myopia progression control.
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Purpose: Contact lenses (CLs) used for myopia control incorporate variable power distribution across the optic zone potentially creating degradation of the high-order aberrations. The present study aims to evaluate the retinal image quality and visual performance in three prototypes of CLs intended to control axial elongation of the eye before they are considered for clinical trials.Methods: This is a non-dispensing cross-over, double-blind study where 30 right eyes of myopic subjects worn 3 multifocal test lenses and 1 monofocal control lens in random order. Lens 1 was a radial refractive gradient design (center distance) and Lens 2 and 3 center-near with an additional annular ring for near. Nominal add power was 2.00D, 1.50D, and 2.00D, respectively. Subjects had an age 21.96 ± 2.23 years [18-30] and mean spherical equivalent refraction M = -2.23 ± 1.50D [-0.75 to -5.50] with refractive astigmatism below -0.75D. Higher-order aberrations (HOA), glare formation (halo), high- and low-contrast LogMAR visual acuity (VA), and contrast sensitivity function (CSF) was measured under monocular conditions.Results: All individual terms of HOA and total root mean square from 3rd to 8th order increased significantly with the 3 test lenses compared to control. Between test lenses, Lens 1 increased significantly the higher HOA compared with Lens 2 and Lens 3. Halo size was significantly larger with test lenses compared with control, with Lens 1 showing the largest. VA under high-contrast conditions was similar for all lenses. Under low-contrast conditions, Lens 1 and Lens 2 performed significantly worse than control (Bonferroni post hoc correction, p < 0.001). CSF was below normal limits with Lens 1 for 3 and 6 cpd spatial frequency but was not significantly different between test lenses and control.Conclusions: Lenses with larger stabilized areas for distance vision interfere less with VA and induce lower values of HOA and image degradation.
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Lentes de Contato Hidrofílicas , Miopia/terapia , Refração Ocular/fisiologia , Acuidade Visual , Sensibilidades de Contraste/fisiologia , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Masculino , Miopia/fisiopatologia , Desenho de Prótese , Adulto JovemRESUMO
PURPOSE: To investigate the effect of different hydrophilic and rigid gas-permeable contact lens (CL) materials on multifocal electroretinography (mfERG). METHODS: The mfERG was recorded in 18 healthy subjects with RETI-port/scan21™: 11 subjects underwent mfERG recording wearing two different hydrophilic CLs with different water contents in a randomized order (1 silicone hydrogel-Comfilcon A, 48%EWC, and 1 hydrogel-Omafilcon A, 62% EWC) and 7 other subjects wore a hydrophobic rigid gas-permeable scleral lens (SL)-Hexafocon A. Control measures were recorded without CL in both groups. mfERG recordings were performed with a stimulus array pattern of 103-scaled hexagons displayed on a 19-inch RGB monitor at 28 cm distance at a frame rate of 60 Hz. The amplitude (nV), implicit time and response density (nV/deg2) of the first-order kernel components N1, P1 and N2 were evaluated for the total mfERG response and for the response averages of 4 quadrants and of 6 successive concentric rings. Subjects were optically corrected for the working distance of ERG display. RESULTS: Hydrophobic material significantly decreased the P1 amplitude of the total mfERG response, at Rings 3, 4 and 6 and Quadrant 4 (> 53.77 ± 43.2 nV; P ≤ 0.050), as well as the total (- 71.59 ± 50.68 nV) and Ring 6 (- 104.76 ± 79.88 nV) N2 amplitude (P ≤ 0.043). N1, P1 and N2 peak times suffered significant changes with both hydrophilic CL (P ≤ 0.050). Omafilcon A significantly increased P1 amplitude of Ring 5 and N2 amplitude of Ring 4, when compared to baseline (52.40 ± 71.87 nV; P = 0.036) and to Comfilcon A (39.51 ± 48.63 nV; P = 0.023), respectively. CONCLUSIONS: Hydrophobic CL slightly attenuated the strength of the mfERG signal, especially at the middle to peripheral retinal areas, while hydrophilic CL slightly changed the implicit time of the response. Different hydrophilic CL materials might affect the mfERG response differently. When considering the measurement of mfERG obtained with a CL in place, researchers should bear in mind that some changes can be related to CL material.
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Lentes de Contato Hidrofílicas , Lentes de Contato , Hidrogéis , Retina/fisiologia , Silicones , Adulto , Eletrorretinografia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
PURPOSE: To report the fitting aspects, clinical findings, and symptoms over 12 months of scleral lens (SL) wear. METHODS: Sixty-nine patients with irregular cornea due to ectasia or surgical procedures (IC group) or regular corneas with high ametropia (RC group) completed the 12-month prospective follow-up period. Patients were evaluated at baseline, lens dispensing visit, 1 month, 3 months, 6 months, and 12 months for assessment of comfort, fitting aspects, and slitlamp findings. Comfort was assessed with the Ocular Surface Disease Index (OSDI) questionnaire and Dry Eye Questionnaire. Slitlamp evaluations comprised on-eye lens fitting (lens alignment and tear reservoir thickness) and anterior ocular surface health after removing the lens (edema, hyperemia, staining, and adverse events). RESULTS: OSDI Scores were significantly reduced after 1 month of SL wear comparing to baseline (from 47.0±22.7-23.9±14.7 in IC group, P<0.001 and 27.0±16.1-17.0±13.7, P=0.029 in RC group, P<0.05), without statistical significant differences from 1 to 12 months. Tear reservoir thickness showed a significant reduction at V1m (122 µm on IC group and 126 µm in RC group, P<0.05), that continued over time until V12m (195 and 184 µm lower compared with Baseline (P<0.05, Wilcoxon). Hyperemia and staining were significantly higher after SL removal when compared with baseline (P<0.05), and maintained the same behavior over the 12 months. There were no severe adverse events during the entire follow-up period. CONCLUSIONS: Comfort enhancement promoted by SL remained over the entire follow-up. Despite no severe adverse events recorded over the 12 months of follow-up, higher hyperemia and staining grades were found after SL removal when compared with no-lens condition.
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Lentes de Contato , Síndromes do Olho Seco , Humanos , Estudos Prospectivos , Esclera , LágrimasRESUMO
BACKGROUND: The aim of this study was to monitor refractive, topographic and biometric changes in Singaporean myopic children fitted with orthokeratology over a period of 12 months. METHODS: Data from 62 myopic eyes from an Asian population corrected with orthokeratology were retrospectively collected from an optometric clinic in Singapore. Anterior segment parameters were analysed with a Pentacam. Axial length was measured using the IOLMaster and refraction was assessed by subjective examination before the treatment and after one night, one week, and one, three, six and 12 months. A logistic regression model was built to evaluate the probability of slower (< 0.10 mm/year) or faster eye growth (≥ 0.10 mm/year). RESULTS: Subjects had a mean age of 12.2 ± 3.9 years (range 5-19 years), and 71 per cent were female. Baseline myopia was -3.95 ± 1.59 D (range -1.50 and -8.75 D). Statistically significant differences were found after 12 months of treatment for refractive error, parameters of the central anterior corneal surface (curvature and elevation) and central corneal thickness. Topographic and thickness changes stabilised after one week of treatment. During 12 months of orthokeratology treatment there was a significant increase of axial length (difference = 0.11 ± 0.18 mm, p < 0.001) while refraction remained stable. Changes in axial length of subjects above 11 years were not statistically significantly independent of the baseline myopia, and in subjects with baseline myopia greater than 4.00 D. Logistic regression showed that each additional year of age and each additional dioptre of baseline myopia decreased the probability of faster axial elongation (odds ratio [OR] = 1.23, 2.19 95% CI; OR = 1.08, 3.47 95% CI, respectively). CONCLUSION: Corneal parameters in orthokeratology treatment were stable after one week, particularly for myopes under 4.00 D. Axial length did not change significantly in children older than 11 years of age or in subjects with myopia above 4.00 D undergoing orthokeratology treatment.
Assuntos
Biometria/métodos , Córnea/diagnóstico por imagem , Topografia da Córnea/métodos , Miopia/terapia , Procedimentos Ortoceratológicos , Refração Ocular/fisiologia , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Masculino , Miopia/diagnóstico , Estudos Retrospectivos , Fatores de Tempo , Adulto JovemRESUMO
PURPOSE: To compare three methods to measure central corneal clearance (CCC) during scleral lens wear: subjective (slit lamp), image processed (ImageJ) and with an optic biometer. The optic biometer technique was validated in comparison to an OCT in the first part of the study. METHODS: Twenty-two eyes (11 subjects) with healthy corneas were recruited. Three measures of OCT with scleral lens and ten measurements of axial length (AL) with IOLMaster with and without lens were performed. For the second part, 61 eyes (35 subjects) enrolled in a clinical study were selected. Measurements of CCC were done with IOLMaster, SlitLamp and ImageJ. RESULTS: The measurements of CCC indirectly obtained with IOLMaster had a strong correlation with AS-OCT measurements (r = 0.981), showing a mean difference of 122.18 ± 46.05 µm (higher with IOLMaster). Regarding the second part, measurements of CCC were 238.66 ± 95.94 µm, 250.16 ± 124.31 µm and 263.15 ± 90.60 µm, for the IOLMaster, SlitLamp and ImageJ, respectively. The correlations were higher for ImageJ vs Subjective measure (r = 0.891) than for IOL vs Subjective (r = 0.748) and IOL vs ImageJ (r = 0.745). Analysis of differences and correlations between SlitLamp and ImageJ through time showed a mean difference of -32.28 ± 89.95 µm (r = 0.683) at V1month, 12.53 ± 59.46 µm (r = 0.850) at V6months and 11.57 ± 32.95 µm (r = 0.940) at V12months. CONCLUSIONS: It is possible to measure CCC with IOLMaster, considering AL measured with and without lens and lens thickness. The three methods tested have good correspondence, showing that IOLMaster and ImageJ could be objective techniques to measure CCC. Also, it is possible to improve the agreement of subjective measures when compared to objective measures trough time.
Assuntos
Biometria/instrumentação , Lentes de Contato , Córnea/anatomia & histologia , Ajuste de Prótese/métodos , Esclera , Adolescente , Adulto , Comprimento Axial do Olho/anatomia & histologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Microscopia com Lâmpada de Fenda , Tomografia de Coerência Óptica , Adulto JovemRESUMO
PURPOSE: To analyze the relationship between corneal sagittal height and asymmetry parameters derived from Placido-videokeratoscopy with the parameters of fitted scleral lenses (ScCLs). METHODS: Corneal topographies were measured with MedmontE300 in a total of 126 eyes with irregular and regular corneas before ScCL fitting were analyzed. Measurements of sagittal height (OC-SAG) at steep and flat corneal meridians were obtained for 10 mm and 12 mm chords. Estimated Height (EHChord) parameters were taken for a chord equal to the diameter of the lens that each subject was wearing at different semi-meridians. Corneal asymmetry (difference in OC-SAG between steep and flat corneal meridians) was also assessed. These outcomes were correlated to ScCL parameters that subjects were wearing after 1 month. RESULTS: The mean ScCL-SAG was 4696 ± 240 µm, and the mean OC-SAG ranged from 1891 µm (10 mm), 2914 µm (12 mm), and between 4162 µm and 4251 µm for EH0-180º and EH30-210º. Stronger correlations (p < 0.001) between OC-SAG and ScCL-SAG were determined for EH0-180º (r = 0.595) and EH30-210º (r = 0.618). The mean differences between OC-SAG and ScCL-SAG were between 447 ± 290 µm (EH0-180º) and 389 ± 360 µm (EH30-210º). There was no relationship between corneal asymmetry and the need to fit a ScCL with toric haptic design in irregular corneas. Orientation of flat corneal and scleral meridians were similar only in corneas with high regular astigmatism. CONCLUSIONS: EHChord attributes were the parameters that best correlated with the ScCL-SAG. The corneal asymmetry was shown to be a poor predictor for the need to fit a ScCL with toricity at landing zone in irregular corneas, but could have some predictive power in regular corneas.