The efficacy of a device-based approach to microorganism disinfection and protein removal for orthokeratology lenses in varied clinical circumstances.

PURPOSE: RigidCare is an electrolysis-based device that recently obtained approval from the US's FDA to sterilise microorganisms and remove proteins for orthokeratology (O-K) lenses. The study was conducted to investigate the device's performance in varied clinical circumstances. METHODS: Trial lenses and private lenses were employed by O-K lens wearers from five hospitals for an evaluation of disinfection and sterilisation and an assessment of protein removal, respectively. Menicon multipurpose solution and protein remover were selected for use with the control group. Following the instructions, pre-cleaning lens samples, post-cleaning lens samples and residual solution samples of trial lenses of the experimental and control groups were collected for microorganism examinations by an experienced third-party testing organisation. The levels of protein deposition for these two approaches were rated by senior O-K experts. Categorical variables were analysed using statistical tests, such as the chi-squared test and Fisher's exact test. RESULTS: The microbial positive rate detected from the pre-cleaning and post-cleaning lens samples and the residual solution of the trial lenses for the experimental and control group was 4/76 vs 1/74 (P = 0.37), 1/76 vs 0/74 (P = 1.00) and 0/76 vs 8/74 (P = 0.006), respectively. Following protein removal, the experimental group exhibited a significantly higher overall proportion of lenses rated as 'clean' or with a 'mild deposit' (96.4 %, 79/82) compared to the control group (85.7 %, 66/77), with a significant difference (P < 0.05). CONCLUSION: This multi-center study demonstrated that RigidCare exhibited superior efficacy in disinfection, sterilisation and protein removal as compared to Menicon multipurpose solution and protein remover.

High myopia control is comparable between multifocal rigid gas-permeable lenses and spectacles.

Purpose: Ocular pathology may be reduced by slowing myopia progression. The purpose of this study was to evaluate the potential of a novel custom-designed rigid gas permeable (RGP) contact lens to control high myopia by comparing the efficacy of multifocal RGP lenses and single-vision spectacles for high myopia control. Methods: The medical records of children fitted with spectacles or multifocal rigid gas-permeable lenses between January 2018 and May 2020 were retrospectively reviewed. Children (5-17 years) with non-cycloplegic spherical equivalent refraction of ≤ -6.00 D or spherical equivalent refraction > - 6.00 D with baseline axial length ≥ 26.5 mm, and astigmatism of ≥ -2.00 D were included. Axial length and refraction were measured at baseline, before fitting the participants with multifocal rigid gas-permeable lenses or spectacles, and at 1- and 2-year follow-up visits. Changes in axial length were compared between the groups. Results: Among the 77 children with 1-year follow-up data, the mean axial elongation was 0.20 ± 0.17 mm and 0.21 ± 0.14 mm in the multifocal rigid gas-permeable and control groups, respectively, without significant differences between groups (F = 0.004, p = 0.835). Among the 41 patients who completed 2 years of follow-up, the mean axial elongation values in the multifocal rigid gas-permeable and control groups were 0.21 ± 0.15 mm and 0.24 ± 0.13 mm, respectively, at the 1-year follow-up, and 0.37 ± 0.27 mm and 0.43 ± 0.23 mm, respectively, at the 2-year follow-up, without significant between-group differences at either time point (p = 0.224). Conclusion: Axial length increased at a similar rate in both the control (spectacles) and multifocal rigid gas-permeable lens groups, suggesting that multifocal rigid gas-permeable lenses have no significant impact on controlling high myopia progression compared with spectacles.

Effect of orthokeratology on axial length elongation in moderate myopic and fellow high myopic eyes of children.

CLINICAL RELEVANCE: The effects of orthokeratology (Ortho-K) on myopic eyes was examined, providing confidence to optometrists applying Ortho-K to high myopic and anisometropic children. BACKGROUND: Ortho-K slows the progression of low to moderate myopia. The effectiveness of Ortho-K in Chinese children with fellow moderate and high myopic eyes was determined. METHODS: This retrospective study included female (n = 35) and male (n = 30) children with moderate myopia in one eye (spherical equivalent refractive (SER) error ≤ -3.00 D, but > -6.00 D) and high myopia in the contralateral eye (SER error ≤ -6.00 D). Three age groups were included: 7-10-years (n = 18), 11-12-years (n = 21), and 13-15-years (n = 26). Baseline refraction and axial lengths were measured before fitting Ortho-K lenses worn nightly for at least eight-hours, and after one-year. RESULTS: Axial length increased 0.14 ± 0.13-mm (mean ± standard deviation) and 0.13 ± 0.16-mm in the moderate and high myopic groups respectively (p = 0.78). For females, axial elongation in the moderate and high myopic groups was 0.10 and 0.08-mm respectively. For males, it was 0.19-mm in both groups. Axial elongation in 7-10-year-old children with moderate and high myopic eyes was 0.24 ± 0.14 and 0.21 ± 0.15-mm respectively. In 11-12-year-old children, it was 0.12-mm in both myopic groups. In 13-15-year-old children, it was 0.09-mm in both groups. In moderate myopic eyes, axial elongation in the youngest group was greater than the other two age groups (p < 0.01). In high myopic eyes, there were no differences among the age groups (p = 0.06). CONCLUSIONS: Ortho-K was equally effective in reducing myopic progression in moderate and in contralateral high myopic eyes. Axial elongation was greater for males than females. For both sexes, it decreased at the same rate with increasing age, regardless of difference in myopia.

[Enhanced near stereopsis after phacoemulsification and implantation of posterior chamber intraocular lens by prescribing addition properly].

OBJECTIVE: To improve near stereopsis in pseudophakic eyes after phacoemulsification and implantation of posterior chamber intraocular lens (IOL). METHODS: This prospective case-series study comprised 92 eyes of 46 patients aged 50 to 70 years [mean age (61.33 +/- 5.54) years] who had phacoemulsification and implantation of posterior chamber IOL, including 24 unilateral pseudophakia (Group A) and 22 bilateral pseudophakia (Group B). The accommodative amplitude, relative accommodation, reading addition, near stereoacuity, etc. were measured. All data were analyzed with the SPSS11.0 for Windows. RESULTS: (1) The mean value of monocular accommodative amplitude in the group A and group B was (2.05 +/- 1.12) and (2.35 +/- 1.30) D, respectively. (2) In the group A and group B, the binocular add was (2.08 +/- 0.37) and (2.13 +/- 0.46) D, respectively, and the monocular add was (2.20 +/- 0.42) and (2.01 +/- 0.39) D, respectively. There was a significant difference between the binocular add and the monocular add (t = 2.33, 2.20, P<0.05) , and between left monocular add and right one (t =3.70, 5.02, P<0.01) in each group. (3) The near stereopsis with monocular add was better than that with binocular add in each group, the difference was significant (X2 = 6.46, 7.02, P = 0.04, 0.03). CONCLUSION: Monocular add is beneficial to a pseudophakia with posterior chamber IOL implantation to improve near stereopsis.

Short term effect of choroid thickness in the horizontal meridian detected by spectral domain optical coherence tomography in myopic children after orthokeratology.

AIM: To investigate choroidal thickness changes in the horizontal meridian after orthokeratology. METHODS: This is a prospective cross-sectional observed study. Subjects (n=30; 11.3±1.7y) with low-to-moderate myopia (-1.0 to -6.0 diopters), wore orthokeratology (Ortho-K) lenses for 3mo. Before and after Ortho-K, OCT scans were made through the fovea in the horizontal meridian. Choroid thickness around the fovea was acquired by custom software. The analyzed regions along the horizontal meridian were divided into 7 equal zones. Ocular parameters were measured by Lenstar LS 900 non-contact biometry. RESULTS: Only the right eye ocular parameters were analyzed in this study. Before Ortho-K, choroidal thickness along the horizontal meridian was 273.7±31.8 µm in the temporal zone, 253.1±38.6 µm in the macula zone, and 194.8±52.2 µm in the nasal zone. After Ortho-K, the choroid was thicker in each horizontal zone (P<0.05). The increased thickness was greatest in the temporal zone (13.5±22.5 µm) and least in the nasal zone (8.4±14.2 µm). The axial length (AL) increased 0.02 mm (P>0.05). The choroid thickness change in each horizontal zone was negatively correlated with AL (r, -0.3 to -0.4; P<0.05) except one of the nasal zones. CONCLUSION: In myopic children, the thickness of the choroid is greatest in the temporal zone and thinnest in the nasal zone. After nightly Ortho-K for 3mo, the thickness increase along the horizontal meridian. The choroid thickness changes are negatively correlated with the change of AL.

Changes and Diurnal Variation of Visual Quality after Orthokeratology in Myopic Children.

PURPOSE: To assess the changes and the diurnal variation of visual quality after orthokeratology in myopic children. METHODS: Forty-four eyes of 22 subjects with a mean age of 10.55 ± 1.53 years (8 to 14 years) were enrolled in this prospective study. Their spherical equivalent ranged from -1.25 to -4.25 diopters (D) and astigmatism was less than 1.00 D. Parameters including corneal curvature, ocular objective scatter index (OSI), the modulation transfer function (MTF), root mean square of ocular and corneal wavefront aberrations, and contrast sensitivity function (CSF) were measured before and at two time points during the same day after 1 month of orthokeratology. RESULTS: After orthokeratology, uncorrected visual acuity (UCVA) and spherical equivalent were significantly improved from baseline (P < 0.001), and their diurnal variation was not significant (P=0.083, 0.568). OSI increased from 0.29 ± 0.15 to 0.65 ± 0.31 (P < 0.001). MTF decreased significantly (P < 0.01). Corneal curvature and ocular total aberration decreased (P < 0.001), while the ocular and corneal higher-order aberration increased significantly (P < 0.01). The CSF under photopic condition decreased at 3 cpd (P=0.006) and increased at 18 cpd (P=0.012). The diurnal variation of CSF at 18 cpd under mesopic and high glare conditions and at 12 cpd under photopic condition was significant (P=0.002, 0.01, 0.017). CONCLUSIONS: Orthokeratology can effectively improve UCVA and high spatial frequency CSF by decreasing the low-order aberrations. However, MTF and CSF at low spatial frequency decreased because of the increase of intraocular scattering and high-order aberrations. Meanwhile, CSF at high spatial frequency fluctuates significantly at two times during the same day after 1 month orthokeratology.