A novel Lenslet-ARray-Integrated spectacle lenses for myopia control: a one-year randomized, double-masked, controlled trial.

PURPOSE: To investigate the myopia control efficacy of novel Lenslet-ARray-Integrated (LARI) spectacle lenses with positive (PLARI) and negative (NLARI) power lenslets worn for one year in myopic children. DESIGN: Randomized, double-masked, controlled clinical trial. PARTICIPANTS: A total of 240 children, aged 6 to 12 years, with spherical equivalent refraction (SER) between -4.00 and -1.00 diopter (D), astigmatism of 1.50 D or less, and anisometropia of 1.00 D or less. METHODS: Participants were assigned randomly in a 1:1:1 ratio to PLARI, NLARI, and a control (single-vision (SV)) groups. Cycloplegic autorefraction and axial length were measured at baseline and 6-month intervals after lens wear. MAIN OUTCOME MEASURES: Changes in SER, axial elongation (AE), and differences between groups. RESULTS: After 1-year, SER changes and AE in the PLARI and NLARI groups were significantly less than those in the SV group (SER: -0.30 ± 0.48 D, -0.21 ± 0.35 D, -0.66 ± 0.40 D; AE: 0.19 ± 0.20 mm, 0.17 ± 0.14 mm, 0.34 ± 0.18 mm, respectively) (all P < 0.001). There were no significant differences in SER changes and AE between PLARI and NLARI groups (P = 0.54 and P = 1.00, respectively). Younger age was associated with more rapid SER increase and larger AE in the SV (r = 0.40, P < 0.001 and r = -0.59, P < 0.001, respectively) and PLARI (r= 0.46, P < 0.001 and r = -0.52, P < 0.001, respectively) groups, but not in the NLARI group (r = -0.002, P = 0.98 and r = -0.08, P = 0.48, respectively). CONCLUSIONS: Compared with the SV group, both PLARI and NARI groups showed significantly slower myopia progression in terms of SER and axial elongation. Faster myopia progression, in terms of both SER and AE, was associated with younger age in the SV and PLARI groups, but not in the NLARI group.

George K. Smelser (1908-1973): Atmospheric oxygen and the corneal response to contact lens wear.

Professor George Smelser was a scientist who played a crucial role in advancing the understanding of the anatomical and physiological changes within the cornea during contact lens wear. In a series of unique experiments conducted in the early 1950s, using both humans and animal models, his research team provided the first conclusive evidence that contact lenses impaired the delivery of atmospheric oxygen to the cornea, resulting in an excess of lactate within the cornea and a subsequent ingress of water, leading to corneal oedema and disturbed vision (Sattler's veil). This historical note reviews the career of George Smelser, with particular emphasis on his contributions to understanding the importance of atmospheric oxygen in maintaining corneal homeostasis.

You've got to hide your myopia away: John Lennon's contact lenses.

John Lennon has an enduring, instantly recognisable, iconic, spectacle look. However, prior to 1966, he was rarely seen wearing glasses in public. From ages 7 to 26, he effectively hid his myopia away, including a period of unsuccessful contact lens wear during Beatlemania. This narrative review examines John's experience with contact lenses from 1963 to 1966 when he wore corneal rigid lenses made from polymethylmethacrylate, which regularly fell out. This frequent lens ejection was most likely due to the interaction between his upper eyelid and a spherical back surface rigid lens fitted to his right eye, which had a moderate degree of with-the-rule corneal astigmatism. John's recollection that his contact lenses stayed in place while 'stoned' supports this hypothesis, as a cannabis-induced upper eyelid ptosis would reduce the likelihood of lens ejection.

The effect of lens and fitting characteristics upon scleral lens centration.

PURPOSE: To quantify the impact of varying central fluid reservoir depth, lens thickness/mass and the addition of a peripheral fenestration upon scleral lens centration. METHODS: Ten young, healthy adults participated in a series of repeated-measures experiments involving short-term (90 min) open eye scleral lens wear. Scleral lens parameters (material, back optic zone radius, diameter, back vertex power and landing zone) were controlled across all experiments, and the central fluid reservoir depth (ranging from 144 to 726 µm), lens thickness (ranging from 150 to 1200 µm), lens mass (101-241 mg) and lens design (with or without a single 0.3 mm peripheral fenestration) were altered systematically. Scleral lens decentration was quantified using over-topography maps. RESULTS: On average, scleral lens centration varied by <0.10 mm over 90 min of wear. Medium and high initial fluid reservoir conditions resulted in 0.17 mm more temporal and 0.55 mm more inferior lens decentration, compared to the low fluid reservoir depth (p < 0.001). Changes in lens thickness or the addition of a peripheral fenestration did not cause clinically significant changes in centration (<0.10 mm on average) when controlling for fluid reservoir depth. Central fluid reservoir depth was the best predictor of horizontal and vertical lens decentration, explaining 62-73% of the observed variation, compared to 40-44% for lens thickness and mass. CONCLUSION: Scleral lens decentration remained relatively stable over 90 min of lens wear. A greater initial central fluid reservoir depth resulted in significantly more lens decentration, particularly inferiorly. Large variations in lens thickness, mass or the addition of a single peripheral fenestration did not substantially affect lens centration.

The effect of landing zone toricity on scleral lens fitting characteristics and optics.

PURPOSE: The fit and optical performance of a scleral lens is affected by the alignment of the landing zone with the underlying ocular surface. The aim of this research was to quantify the effect of landing zone toricity upon scleral lens fitting characteristics (rotation and decentration) and optics (lens flexure) during short-term wear. METHODS: Scleral lenses with nominal landing zone toricities of 0, 100, 150 and 200 µm were worn in a randomised order by 10 young healthy participants (mean [SD] 24 [7] years) for 30 min, with other lens parameters held constant. Scleral toricity was quantified using a corneo-scleral profilometer, and lens flexure, rotation, and decentration were quantified using over-topography during lens wear. Repeated measures analyses were conducted as a function of landing zone toricity and residual scleral toricity (the difference between scleral and lens toricity) for eyes with 'low' magnitude scleral toricity (mean: 96 µm) and 'high' magnitude scleral toricity (mean: 319 µm). RESULTS: Toric landing zones significantly reduced lens flexure (by 0.37 [0.21] D, p < 0.05) and lens rotation (by 20 [24]°, p < 0.05) compared with a spherical landing zone. Horizontal and vertical lens decentration did not vary significantly with landing zone toricity. These trends for flexure, rotation, and decentration were also observed for eyes with 'low' and 'high' magnitude scleral toricity as a function of residual scleral toricity. CONCLUSION: Landing zones with 100-200 µm toricity significantly reduced lens flexure (by ~62%) and rotation (by ~77%) but not horizontal or vertical lens decentration, compared with a spherical landing zone, when controlling for other confounding variables. The incorporation of a toric landing zone, even for eyes with lower magnitude scleral toricity (~100 µm), may be beneficial, particularly for front surface optical designs.

Higher order aberrations and retinal image quality during short-term accommodation in myopic and non-myopic children.

INTRODUCTION: Despite the known associations between near work and myopia, and retinal image quality and eye growth, accommodation-induced changes in higher order aberrations (HOA's) and retinal image quality in children with different refractive errors are poorly understood. METHODS: Ocular HOA's were measured using a Hartmann-Shack wavefront sensor (COAS-HD, Wavefront Sciences) in 18 myopic and 18 age- and sex-matched non-myopic children during short-term accommodation tasks (four demands of 0, 3, 6 and 9 D) presented using a Badal optometer. Eighth order Zernike polynomials were fitted across a 2.3 mm pupil diameter to determine refractive power vectors (M, J180 and J45 ) and the accommodation error, and a 4 mm pupil was used for HOA analyses. Retinal image quality was examined using the visual Strehl ratio based on the optical transfer function (VSOTF) for third to eighth radial orders only. RESULTS: Most refractive error group differences were observed for the 6 and 9 D demands. Myopic children underwent greater changes in with-the-rule astigmatism (J180 ), higher order and third order RMS values, primary vertical ( C 3 - 1 ) and horizontal coma ( C 3 1 ), and several other individual Zernike coefficients compared with non-myopic children (all refractive error group by demand interaction p-values of ≤0.02). Non-myopic children exhibited a greater negative shift in primary ( C 4 0 ) and positive shift in secondary spherical aberration ( C 6 0 ) (both refractive error group by demand interaction p-values of ≤0.002). The VSOTF degraded for the 6 and 9 D demands in both groups, but the myopic children underwent a greater mean (SE) reduction from 0 D of -0.274 (0.048) for the 9 D demand, compared with -0.131 (0.052) for the non-myopic children (p = 0.001). CONCLUSION: These results may have implications for the association between near work, accommodation and myopia development, particularly related to the use of short working distances during near tasks.

Central and peripheral scleral lens-induced corneal oedema.

PURPOSE: To quantify the magnitude of central and peripheral scleral lens-induced corneal oedema for a range of fluid reservoir thicknesses, and to compare these experimental results with theoretical models of corneal oedema both with and without limbal metabolic support (i.e., the lateral transport of metabolites and the influence of the limbal vasculature). METHODS: Ten young healthy participants wore scleral lenses (KATT™, Capricornia Contact Lenses) fitted with low (mean 141 µm), medium (482 µm) and high (718 µm) central fluid reservoir thickness values across three separate study visits. The scleral lens thickness, fluid reservoir thickness and stromal corneal oedema were measured using optical coherence tomography. Oedema was quantified across the central (0-2.5 mm from the corneal apex) and peripheral (1.25-3 mm from the scleral spur) cornea. Experimental data were compared with published theoretical models of central to peripheral corneal oedema. RESULTS: Stromal oedema varied with fluid reservoir thickness (p < 0.001) for both central and peripheral regions. The mean (standard deviation) stromal oedema was greater for the medium (2.08 (1.21)%) and high (2.22 (1.31)%) fluid reservoir thickness conditions compared to the low condition (1.00 (1.01)%) (p ≤ 0.01). Stromal oedema gradually increased from the corneal centre to the periphery by ~0.3% on average (relative increase of 18%), but the change did not reach statistical significance. This trend of increasing, rather than decreasing, oedema towards the limbus is consistent with theoretical modelling of peripheral oedema without metabolic support from the limbus. CONCLUSIONS: The central and peripheral cornea displayed a similar magnitude of oedema, with increasing levels observed for medium and high fluid reservoir thicknesses. The gradual increase in oedema towards the limbus is consistent with a 'without limbal metabolic support' theoretical model.

Corneal oedema during reverse piggyback scleral lens wear.

PURPOSE: One clinical approach to address poor front surface wettability during scleral lens wear is the use of a "reverse piggyback" system (a soft contact lens applied to the anterior surface of a scleral lens). The aim of this study was to compare the magnitude of corneal oedema induced following short-term reverse piggyback scleral lens wear and standard scleral lens wear. METHODS: Ten young (mean age 22 ± 6 years) healthy participants with normal corneas were recruited. On separate days, central corneal thickness and fluid reservoir thickness were measured using optical coherence tomography before and after 90 min of standard scleral lens wear (Kerectasia Alignment Tangent Torus diagnostic lenses, hexafocon A, Dk 100 × 10-11 (cm2 /s)(ml O2 /ml × mmHg), Capricornia Contact Lenses, capcl.com.au) and reverse piggyback scleral lens wear (the same scleral lens with a Dailies Total 1®, delefilcon A, Dk 140 × 10-11 (cm2 /s)(ml O2 /ml × mmHg), Alcon, alcon.com, applied to the anterior scleral lens surface). RESULTS: After correcting for small variations in the initial central fluid reservoir thickness, central corneal oedema was similar between the reverse piggyback (2.32 ± 1.15%) and standard scleral lens conditions (2.02 ± 0.76%; p = 0.45). CONCLUSIONS: Following 90 min of lens wear, the highly oxygen-permeable reverse piggyback system did not induce a clinically or statistically greater magnitude of central corneal oedema compared with standard scleral lens wear in young adults with healthy corneas. This approach may be suitable to address poor front surface scleral lens wettability or to correct residual refractive error during diagnostic scleral lens fitting.

Long-term limitations and complications of trans-scleral diode laser cycloablation for refractory glaucoma.

BACKGROUND: Trans-scleral diode laser cycloablation (cyclodiode) is effective in the short-term management of refractory glaucoma where alternative treatments are not feasible. Long-term outcomes of 5-years or more are not well-documented, particularly in relation to intraocular pressure (IOP) control, need for further procedures and complications such as hypotony and phthisis. METHODS: A review was undertaken of patient medical records with refractory glaucoma who underwent cyclodiode at City Eye Centre in Brisbane from 2012 to 2016. Data included sex, age, laterality, type of glaucoma, cyclodiode parameters, number of glaucoma medications, visual acuity and treatment with acetazolamide. Data were analysed using generalised linear modelling and Kaplan-Meier analysis. RESULTS: A total of 54 eyes in 54 patients (29 M:25F) with a mean age of 66 years (range 15-85 years) with a minimum of 5 years follow up were included. The mean number of burns was 23.3 (range 12-40) over 180-270 degrees, mean power per burn was 1967 mW (range 1500-2000 mW), with a mean duration of 1981 ms (1500-2000 ms). The mean pre-treatment IOP was 31.5 mmHg (range 17-56 mmHg) and mean IOP 5 years post-treatment was 16.1 mmHg (2-42 mmHg). The mean number of pre-treatment medications was 3.6 (range 1-6) and 2.7 (range 0-5) 5 years post treatment, including 5 (8.3%) on oral acetazolamide. Complications of cyclodiode were seen in 6 (11.1%) patients, including 3 (5.0%) cases of hypotony, and 2 (3.3%) phthisis. CONCLUSION: Cyclodiode is often utilised for end-stage glaucoma when the IOP is uncontrolled on medical treatment and drainage surgery is not indicated, resulting in long-term reduction of IOP and the number of medications, including acetazolamide. Hypotony and phthisis can be significant complications.

Corneal oedema during open-eye fenestrated scleral lens wear.

INTRODUCTION: Studies examining the effect of fenestrating soft and corneal rigid contact lenses upon corneal oedema have yielded conflicting results. Although often utilised in clinical practice, no studies have quantified the effect of fenestrating a scleral contact lens upon corneal oedema. Therefore, the aim of this experiment was to examine the effect of incorporating a single peripheral fenestration on central corneal oedema during short-term open-eye scleral lens wear, while controlling for potential confounding variables. METHODS: Nine participants (mean age 30 years) with normal corneas wore a fenestrated (1 × 0.3 mm limbal fenestration) and non-fenestrated scleral lens (both lenses manufactured using a material Dk of 141 × 10-11  cm3 O2 (cm)/[(sec.)(cm2 )(mmHg)]) under open-eye conditions on separate days. Scleral lens thickness profiles were measured using a high-resolution optical coherence tomographer (OCT). Epithelial, stromal and total central corneal oedema were also measured using the OCT immediately after lens application and following 90 min of wear, prior to lens removal. RESULTS: After adjusting for differences in initial central fluid reservoir thickness and scleral lens thickness between the two lens conditions, the mean (standard error) total corrected central corneal oedema was 0.50 (0.36)% for the fenestrated lens and 0.62 (0.16)% for the non-fenestrated lens. This small difference was not statistically significant (t8  = 2.31, p = 0.81) and represents a 19% relative reduction in central corneal oedema. Similarly, epithelial (t8  = 2.31, p = 0.82) and stromal (t8  = 2.31, p = 0.92) corneal oedema were not significantly different following the fenestrated and non-fenestrated wearing conditions. CONCLUSION: Central corneal oedema in healthy corneas was comparable between fenestrated and non-fenestrated high Dk scleral lenses under short-term open-eye conditions when controlling for lens oxygen transmissibility and initial central fluid reservoir thickness.

Scleral Lens Thickness and Corneal Edema Under Closed Eye Conditions.

OBJECTIVES: To examine the relationship between central lens thickness and central corneal edema during short-term closed eye scleral lens wear. METHODS: Nine participants (mean age 30 years) with normal corneas wore scleral lenses (Dk 141) under closed eye conditions on separate days with nominal center thicknesses of 150, 300, 600, and 1,200 µm. Epithelial, stromal, and total corneal edema were measured using high-resolution optical coherence tomography immediately after lens application and after 90 min of wear, before lens removal. Data were corrected for variations in initial fluid reservoir thickness and compared with predictions from theoretical modeling of overnight scleral lens wear. RESULTS: Scleral lens-induced central corneal edema was primarily stromal in nature. The mean±standard error of corrected total corneal edema was 4.31%±0.32%, 4.55%±0.42%, 4.92%±0.50%, and 4.83%±0.22% for the 150-, 300-, 600-, and 1,200-µm lenses, respectively. No significant differences in the corrected total corneal edema were observed across all thickness groups (P=0.20). Theoretical modeling of overnight scleral lens wear seemed to overestimate the relative increase in central corneal edema as a function of decreasing lens Dk/t for values lower than 25. CONCLUSION: The magnitude of scleral lens-induced central corneal edema during short-term closed eye lens wear did not vary significantly with increasing central lens thickness. Theoretical modeling of overnight closed eye scleral lens wear seems to overestimate the effect of increasing lens thickness.

Scleral Lens Thickness and Corneal Edema Under Open Eye Conditions.

PURPOSE: To examine the relationship between lens thickness and central corneal edema during short-term open-eye scleral lens wear, and to compare these empirical edema measurements with theoretical modelling. METHODS: Nine participants (mean age 30 years) with normal corneas wore scleral lenses {Dk 141×10-11 cm3 O2 [cm]/([sec] [cm2] [mm Hg])} under open-eye conditions on separate days with nominal center thicknesses of 150, 300, 600, and 1,200 µm. Epithelial, stromal, and total corneal edema were measured using high-resolution optical coherence tomography immediately after lens application and after 90 min of wear, before lens removal. RESULTS: Central corneal edema was primarily stromal in nature and increased with increasing central lens thickness. The mean±standard error total corneal edema was 1.14±0.22%, 1.36±0.26%, 1.74±0.30%, and 2.13±0.24% for the 150, 300, 600, and 1,200 µm lenses, respectively. A significant difference in stromal and total corneal edema was observed between the 1,200 and 150 µm thickness lenses only (both P<0.05). Theoretical modelling overestimated the magnitude of central corneal edema and the influence of central lens thickness when the scleral lens Dk/t was less than 20. CONCLUSION: Scleral lens-induced central corneal edema during short-term open-eye lens wear increases with increasing central lens thickness. Theoretical models overestimated the effect of increasing scleral lens thickness upon central corneal edema for higher lens thickness values (lens Dk/t<20) when controlling for initial central fluid reservoir thickness.

Corneal Biomechanics and Intraocular Pressure Following Scleral Lens Wear in Penetrating Keratoplasty and Keratoconus.

OBJECTIVE: To compare corneal biomechanics and intraocular pressure (IOP) in keratoconus and penetrating keratoplasty eyes before and after nonfenestrated scleral lens wear. METHODS: Twenty-three participants were enrolled, and 37 eyes were included in the analysis (11 penetrating keratoplasty and 26 keratoconus). A range of corneal biomechanical parameters and IOP were measured using the CORVIS ST before and after 8 hr of nonfenestrated scleral lens wear (Keracare, Acculens, Denver, CO). RESULTS: Before lens wear, penetrating keratoplasty eyes displayed significantly greater median values for central corneal thickness (97 µm thicker, P=0.02), IOP (3.89 mm Hg higher, P=0.01), and biomechanical parameter A2 length (0.48 mm longer, P=0.003) compared with keratoconic eyes. No significant changes in corneal biomechanical parameters or IOP were observed after scleral lens wear in either group (all P>0.05). CONCLUSION: Although nonfenestrated scleral contact lenses can induce a subatmospheric pressure after lens settling and compress tissue surrounding the limbus, no significant changes were detected in the corneal biomechanical parameters studied using CORVIS ST after scleral lens wear in eyes with penetrating keratoplasty and keratoconus.

Effects of brief periods of clear vision on the defocus-mediated changes in axial length and choroidal thickness of human eyes.

PURPOSE: To investigate the influence of brief, repeated periods of clear vision on the changes in axial length and choroidal thickness in response to short-term imposed defocus. METHODS: The right eye of 16 young adults was exposed to 60 min episodes of continuous and interrupted defocus conditions (+3 DS and -3 DS) over five separate sessions, with the left eye optimally corrected for distance. For interrupted defocus, 2 min episodes of clear vision were imposed before each 15 min episode of myopic or hyperopic defocus (2/15 min). For hyperopic defocus, the effect of frequency of clear vision exposure was also assessed by imposing 1 min of clear vision before each 7.5 min of defocus (1/7.5 min). The right eye axial length and choroidal thickness were measured before, during and after each defocus condition. RESULTS: After 60 min of continuous hyperopic defocus the eye elongated significantly by +9 ± 9 µm (p = 0.02). When exposed to interrupted (2/15 min) hyperopic defocus, axial elongation was significantly reduced by 77% compared to continuous hyperopic defocus (p = 0.03), with a final change of only +2 ± 10 µm relative to baseline. During interrupted (1/7.5 min) hyperopic defocus, axial elongation reduced slightly compared to continuous hyperopic defocus (+6 ± 8 µm relative to baseline, p = 0.12). For continuous myopic defocus, a reduction in axial length occurred but was not statistically significant (p > 0.05). A similar pattern of response was observed for choroidal thickness changes with continuous and interrupted (1/7.5 min) hyperopic defocus conditions. CONCLUSIONS: Brief periods of clear vision can diminish axial elongation and choroidal thinning induced by hyperopic defocus exposure in human eyes. If hyperopic defocus contributes to myopia progression in humans, then interruption with brief periods of clear vision could reduce its myopiagenic effects.

Comparison between estimated and measured myopia progression in Hong Kong children without myopia control intervention.

PURPOSE: To compare myopia progression estimated by the Brien Holden Vision Institute (BHVI) Myopia Calculator with cycloplegic measures in Hong Kong children wearing single-vision distance spectacles over a 1- and 2-year period. METHODS: Baseline age, spherical equivalent refraction (SER) and ethnicity of control participants from previous longitudinal myopia studies were input into the BHVI Myopia Calculator to generate an estimate of the SER at 1 and 2 years. Differences between the measured and estimated SER (116 and 100 participants with 1- and 2-year subjective refraction data, respectively, and 111 and 95 participants with 1- and 2-year objective refraction, respectively) were analysed, and the measured SER compared with the 95% confidence interval (CI) of the estimated SER. RESULTS: In children aged 7-13 years, 36% progressed within the 95% CI of the Myopia Calculator's estimate, whereas 33% became less myopic than predicted (range 0.31 to 1.92 D less at 2 years) and 31% became more myopic than predicted (range 0.25 to 2.33 D more myopic at 2 years). The average difference between the estimated and measured subjective or objective SER at 1 and 2 years of follow-up was not clinically significant (<0.25 D). CONCLUSIONS: On average, the BHVI Myopia Calculator estimated SER was in close agreement with measured cycloplegic SER after 1 and 2 years of follow-up (mean differences < 0.25 D). However, the measured myopia progression only fell within the 95% CI of the estimated SER for 32%-38% of children, suggesting that the BHVI 'without management' progression data should be interpreted with caution. The inclusion of additional data, modified to include axial elongation, from longitudinal studies of longer duration with larger sample sizes and a range of racial backgrounds may improve the Calculator's ability to predict future myopia progression for individual children.

The effect of scleral lenses on vision, refraction and aberrations in post-LASIK ectasia, keratoconus and pellucid marginal degeneration.

PURPOSE: To quantify the effect of a single scleral lens design on visual acuity and ocular higher-order aberrations in eyes with post-LASIK ectasia, keratoconus and pellucid marginal degeneration (PMD) that could not achieve satisfactory vision with spectacles or soft contact lenses. METHODS: Forty-six eyes of 28 participants fitted with diagnostic scleral lenses (KeraCare) were analysed, including 19, 15 and 12 eyes with post-LASIK ectasia, keratoconus and PMD, respectively. Corrected distance visual acuity (CDVA) and ocular aberrations were measured prior to lens wear and during lens wear after 60 min of settling. An i-Trace aberrometer was used to determine aberrations over a 4.5 mm diameter pupil. RESULTS: Before lens wear, the median (95% confidence interval) values across all groups were: CDVA 0.30 (0.30, 0.40) logMAR, spherical equivalent refraction -2.75 (-5.25, -2.12) D, cylindrical refraction 3.75 (2.50, 5.00) D, higher-order-root-mean-square error (HO-RMS) 0.90 (0.64, 1.03) µm and vertical coma co-efficient C(3,-1) -0.32 (-0.42, -0.12) µm. RMS coma of 0.52 (0.40, 0.74) µm was higher for the keratoconus group than for the other groups (p < 0.05). During lens wear, values improved considerably across all groups: CDVA 0.0 (0.0, 0.00) logMAR, spherical equivalent refraction -0.50 (-0.75, +0.50) D, cylindrical refraction 0.50 (0.00, 0.50) D, HO-RMS 0.32 (0.26, 0.42) µm and C(3,-1) +0.12 (+0.02, +0.19) µm (all p < 0.001 compared to pre-lens wear). While reduced significantly, RMS coma remained higher in the keratoconus group at 0.35 (0.31, 0.52) µm than in the post-LASIK ectasia and PMD groups at 0.17 (0.12, 0.21) µm and 0.07 (0.02, 0.46) µm, respectively (p < 0.05). CONCLUSIONS: The KeraCare scleral contact lens reduced ocular aberrations and improved visual acuity in patients with post-LASIK ectasia, keratoconus and PMD. The sign of vertical coma changed in keratoconus and PMD.

Compression Factor and Visual Performance in Adults Treated With Orthokeratology.

OBJECTIVES: To investigate the effect of compression factor on visual performance in orthokeratology (ortho-k). METHODS: Myopic adults were fitted with ortho-k lenses with either a 0.75 diopter (D) or 1.75 D compression factor. Higher-order aberrations (HOAs), corneal topography, and responses to the National Eye Institute/Refractive Error Quality of Life Instrument-42 questionnaire were measured at baseline and 6-month and 12-month follow-up along with a satisfaction questionnaire. Subjective refraction, high-contrast, and low-contrast visual acuity were measured at baseline and 1-day, 1-week, 6-month, and 12-month follow-up. RESULTS: Forty-four myopic (mean spherical equivalent refraction: -3.66±0.84 D) adults (median age 25 years) completed the 12-month follow-up. After ortho-k lens wear, levels of satisfaction of vision after waking were significantly higher than vision before sleep for both compression factors (both P<0.01). The increased compression factor (ICF) resulted in less myopia at the 1-week visit (P=0.04) and better high-contrast unaided visual acuity at the 1-day visit (P=0.03) compared with the conventional compression factor (CCF). No other significant differences were observed for the compression factor for treatment zone diameter, lens decentration, or any subjective measurements. Individual HOA terms , , , and were significantly higher in the CCF group (0.75 D) (all P<0.05). The HOA visual Strehl ratio decreased significantly after lens wear (P<0.001) but did not vary with the compression factor. CONCLUSIONS: An ICF did not result in clinically significant differences in subjective refraction, visual acuity, unaided vision, or the total ocular HOA profile compared with a CCF (0.75 D) in myopic adults after long-term ortho-k lens wear.

Scleral Lens-Induced Corneal Edema After Radial Keratotomy.

ABSTRACT: This case series examines the magnitude and regional variation in scleral lens-induced corneal edema in postradial keratotomy (RK) eyes. Scheimpflug imaging was used to measure corneal thickness across the central 6 mm before and after scleral lens wear in nine post-RK eyes (median age 64 years). Variations in corneal edema were examined as a function of distance from the corneal center (six 0.5-mm annuli) and from 0° to 360°. The median central corneal edema was 2.19% (interquartile range 1.03%-3.18%; P=0.02) and increased in magnitude and variability further from the central cornea (from 1.30% in the central 0-0.5 mm to 3.12% in the 2.5-3.0 mm midperiphery) (P=0.02). Scleral lens-induced corneal edema in post-RK eyes was greater in magnitude further from the corneal center and at the approximate location of corneal incisions.

Scleral Lens Visual Rehabilitation of Sequential Bilateral Corneal Hydrops With Post-LASIK Ectasia.

ABSTRACT: This case report describes a unique presentation of bilateral sequential acute corneal hydrops that manifested several years after laser in situ keratomileusis. Initial management included anterior chamber perfluoropropane gas injection and corneal suturing. Longer-term visual rehabilitation involved the use of scleral lenses which significantly reduced lower- and higher-order ocular aberrations.

Scleral Lens-Induced Corneal Edema after Penetrating Keratoplasty.

SIGNIFICANCE: Modern highly oxygen-permeable nonfenestrated scleral lenses induce approximately 1 to 2% corneal edema after short periods of lens wear in healthy individuals. This study investigated the magnitude and regional variation in scleral lens-induced central corneal edema after penetrating keratoplasty. PURPOSE: The purpose of this study was to examine the magnitude and regional variation in corneal edema after a short period of scleral lens wear in post-penetrating keratoplasty eyes and a control group of eyes with healthy corneas. METHODS: Nine post-penetrating keratoplasty eyes (nine participants; mean age, 32 years) were fitted with highly oxygen-permeable nonfenestrated scleral lenses (Dk 100 × 10 cm O2 (cm)/[(s) (cm) (mmHg)]). Central corneal thickness was measured using Scheimpflug imaging before lens insertion and immediately after lens removal (mean wearing time, 6.2 hours). Corneal edema was quantified across the central 6 mm and compared with data obtained from a historical control group of healthy eyes using a similar experimental paradigm. RESULTS: Post-penetrating keratoplasty eyes exhibited significant corneal edema after lens wear (2.99% [95% confidence interval, 1.13 to 4.85%]) averaged across the central 6 mm (P = .006) and regional variations in edema (P < .001) (greater swelling toward the graft-host junction inferiorly). Compared with healthy eyes, post-penetrating keratoplasty eyes displayed a greater magnitude of corneal edema (by ~3×) and greater variability in the corneal response (by ~2.5×). CONCLUSIONS: Scleral lens-induced central corneal edema is greater in post-penetrating keratoplasty eyes and varies regionally compared with healthy corneas after short-term wear. Lens design and fitting factors contributing to hypoxic and mechanical corneal stress should be carefully considered for all post-penetrating keratoplasty scleral lens fits to minimize potential graft rejection or failure in the longer-term.