We conducted this study to explore the influence of the ocular residual aberrations changes on contrast sensitivity (CS) function in eyes undergoing orthokeratology using adaptive optics technique. Nineteen subjects' nineteen eyes were included in this study. The subjects were between 12 and 20 years (14.27±2.23 years) of age. An adaptive optics (AO) system was adopted to measure and compensate the residual aberrations through a 4-mm artificial pupil, and at the same time the contrast sensitivities were measured at five spatial frequencies (2,4,8,16, and 32 cycles per degree).The CS measurements with and without AO correction were completed. The sequence of the measurements with and without AO correction was randomly arranged without informing the observers. A two-interval forced-choice procedure was used for the CS measurements. The paired t-test was used to compare the contrast sensitivity with and without AO correction at each spatial frequency. The results revealed that the AO system decreased the mean total root mean square (RMS) from 0.356 μm to 0.160 μm(t=10.517, P＜0.001), and the mean total higher-order RMS from 0.246 μm to 0.095 μm(t=10.113, P＜0.001). The difference in log contrast sensitivity with and without AO correction was significant only at 8 cpd (t=-2.51, P=0.02). Thereby we concluded that correcting the ocular residual aberrations using adaptive optics technique could improve the contrast sensitivity function at intermediate spatial frequency in patients undergoing orthokeratology.
Objective To investigate the influence of undercorrected orthokeratology on myopia control, and the correlation between target and central corneal epithelial damage. Methods A retrospective study was conducted on 22 undercorrected orthokeratology lens wearers (37 eyes) from January 2016 to February 2017, and 25 full corrected wearers (47 eyes) during the concurrent period were randomly selected as the control group. The changes of axial length before and after orthokeratology lens wearing and the within-6-month central corneal epithelial damage after orthokeratology lens wearing were analyzed. Results The average annual increase of axial length was (0.13±0.15) mm in the undercorrected group, and (0.14±0.16) mm in the full corrected group, the difference was not statistically significant (P>0.05). Multiple linear regression analysis showed that there was no correlation between the axial growth and the undercorrection of the target (P>0.05), but a negative correlation between the axial growth and the age (P<0.01). After using orthokeratology, the average annual growth of the axial length in children aged 7-10 years was (0.25±0.16) mm, and (0.10±0.14) mm in children aged 11-15 years, the difference was statistically significant (P<0.01). The incidence of central corneal epithelial punctate staining in the (–4.25)-(–5.00) D target group was 27.08%, and that in the (–3.00)-(–4.00) D target group was 16.67%, the difference was not statistically significant (P>0.05). Conclusions The effect of orthokeratology on myopia growth is not affected by the undercorrected target, not related to the undercorrection of target, but negatively correlated with the age. Undercorrected orthokeratology can still be used for myopia control in high myopia patients. No correlation is found between the target and central corneal staining.
ObjectiveTo investigate whether the corneal shape recovered after discontinuation of long-term orthokeratology and whether orthokeratology increased the corneal astigmatism and ocular astigmatism.MethodsFrom December 2016 to April 2018, a retrospective study was conducted on 33 myopic patients who had undergone two times standard orthokeratology in the outpatient department of West China Hospital of Sichuan University, and had stopped wearing the first orthokeratology lens for one month before fitting the second orthokeratology lens. A total of 32 myopia frame glasses wearers were selected by simple random sampling as control. The changes of corneal flat meridian curvature (flat K), corneal steep meridian curvature (steep K), corneal astigmatism and ocular astigmatism before and after discontinuation of orthokeratology were analyzed.ResultsAmong the patients with baseline myopia diopter of −0.25～−2.75 D, the average annual change of corneal flat K was (−0.03±0.21) D in the frame glasses group and (−0.24±0.14) D in the orthokeratology group, the difference was statistically significant (t=5.555, P<0.001). Among the patients with baseline myopia diopter of −0.25～−2.75 D, the average annual change of corneal steep K was (0.20±0.42) D in the frame glasses group and (0.15±0.20) D in the orthokeratology group, the difference was not statistically significant (t=0.785, P=0.435). Among the patients with baseline myopia diopter of −3.00～−5.75 D, the average annual change of corneal steep K was (0.29±0.39) D in the frame glasses group and (−0.01±0.20) D in the orthokeratology group, the difference was statistically significant (t=2.758, P=0.014). The average changes of corneal astigmatism were analyzed according to the difference of eyes, gender, age and baseline corneal astigmatism, the difference was not statistically significant (P>0.05), respectively. For patients with baseline astigmatism absolute value less than or equal to 0.50 D, the astigmatism annual change of the frame glasses group was 0.00 (0.50) D, and that of orthokeratology group was −0.33 (0.48) D, the difference was statistically significant (Z=−2.301, P=0.021).ConclusionsThe flat K of the cornea becomes flatter and the steep K does not change after one month’s discontinuation of long-term orthokeratology. There was no difference in the increase of corneal astigmatism compared with those wearing frame glasses. When the baseline ocular astigmatism is less than or equal to 0.50 D, the increase of astigmatism may occur after discontinuation of orthokeratology.
ObjectiveTo investigate the effect of “noncycloplegic retinoscopy for screening myopia + subsequent wearing orthokeratology lens” process for primary and secondary school students based on physical examination center.MethodsA total of 172 primary and secondary school students undergoing vision examination in the Health Management Department (i.e. physical examination center) of the Second Affiliated Hospital of Xi’an Jiaotong University between January 2017 and December 2018 were selected as the research objects. After examination by noncycloplegic retinoscopy in the health management department, they were examined by mydriatic retinoscopy in the ophthalmology department, and then the consistency of the results of the two methods was analyzed. Then 93 students with myopia diagnosed by both methods were randomly divided into control group (n=46) and trial group (n=47), wearing frame glasses and orthokeratology lenses respectively. The diopter, eye axial length, corneal curvature and vitreous cavity depth before wearing glasses, as well as the increment of the above indicators at 3, 6 and 12 months after wearing glasses/lenses were compared between the two groups, and the incidence of complications of the two groups were compared.ResultsCompared with mydriatic retinoscopy, the positive predictive value of noncycloplegic retinoscopy was 88.6%, the sensitivity was 96.9% and the specificity was 84.2%, and the consistency kappa coefficient was 0.821 (P<0.001). Before wearing glasses/lenses, there was no significant difference in diopter, eye axial length, corneal curvature or vitreous cavity depth of both eyes between the two groups (P>0.05); at 3, 6 and 12 months after wearing glasses/lenses, the diopter increment and eye axial increment of both eyes of the trial group were less than those of the control group [left eye diopter increment: (0.48±0.07) vs. (0.73±0.08) D, (0.69±0.13) vs. (1.04±0.11) D, (0.88±0.11) vs. (1.13±0.11) D; left eye axial increment: (0.18±0.05) vs. (0.26±0.04)mm, (0.22±0.04) vs. (0.36±0.04) mm, (0.27±0.05) vs. (0.40±0.05) mm; right eye diopter increment: (0.46±0.10) vs. (0.73±0.09) D, (0.71±0.12) vs. (1.04±0.10) D, (0.90±0.10) vs. (1.17±0.11) D; right eye axial increment: (0.17±0.04) vs. (0.24±0.04) mm, (0.23±0.04) vs. (0.37±0.04) mm, (0.26±0.05) vs. (0.42±0.05) mm] (P<0.05). At 3, 6 and 12 months after wearing glasses/lenses, the changing trends of corneal curvature and vitreous cavity depth in both eyes of the trial group were different from those of the control group (PInteraction<0.05), and the corneal curvature of both eyes at each time point was lower than that before wearing lenses and that of the control group (P<0.05), while the vitreous cavity depth of both eyes was not statistically different from that before wearing lenses (P>0.05) but lower than that of the control group (P<0.05). There was no statistical difference in the incidence of common complications between the two groups (P>0.05).ConclusionIn the physical examination center, the accuracy of noncycloplegic retinoscopy for general survey of myopia in primary and secondary school students is high, and then after the diagnosis by mydriatic retinoscopy in the special department, the use of orthokeratology lens can effectively control the progress of myopia, so the process of “noncycloplegic retinoscopy for screening myopia in physical examination center + subsequent wearing orthokeratology lens in specialty” is feasible.
ObjectiveTo compare the changes of corneal astigmatism after long-term spherical and toric orthokeratology wearing, and to investigate the effects of different orthokeratology design on corneal astigmatism.MethodsThe medical records of myopic adolescent patients who have been prescribed spherical and toric orthokeratology in the contact lens clinic of West China Hospital, Sichuan University between January 2019 and December 2021 were analyzed retrospectively.The differences of corneal astigmatism changes after wearing spherical and toric orthokeratology for a long time and one month discontinuation were compared. The influencing factors of corneal astigmatism changes were analyzed. ResultsA total of 156 patients were included. There were 76 cases (76 eyes) in spherical orthokeratology group and 80 cases (80 eyes) in toric orthokeratology group. There was no significant difference between the two groups in age, gender, baseline myopia diopter and total lens wearing time (P>0.05). There were statistically significant differences between the spherical orthokeratology group and the toric orthokeratology group in the baseline corneal flat K value [42.1 (41.3, 43.3) vs. 43.1 (42.0, 44.1) D], baseline corneal steep K value [(43.4±1.3) vs. (44.6±1.5) D], baseline corneal astigmatism [(1.1±0.5) vs. (1.6±0.6) D], and baseline total eye astigmatism [−0.6 (−1.2, 0.0) vs. −1.4 (−1.8, −1.0) D] before wearing the orthokeratology (P<0.05). Compared with the baseline value, 1 month after the two groups stopped wearing the orthokeratology, the corneal flat K values became flatter [spherical orthokeratology group: 42.09 (41.28, 43.34) vs. 41.73 (40.98, 43.16) D, toric orthokeratology group: 43.09 (41.95, 44.10) vs. 42.61 (41.52, 43.56) D; P<0.05], the changes of corneal steep K values were not statistically significant (P>0.05), but the corneal astigmatism values increased [spherical orthokeratology group: (1.05±0.49) vs. (1.37±0.56) D, toric orthokeratology group: (1.62±0.57) vs. (1.99±0.63) D; P<0.05]. There was no significant difference in the changes of corneal flat K value, corneal steep K value and corneal astigmatism between the two groups (P>0.05). Multivariate analysis showed that age (P=0.011) and the total duration of orthokeratology wearing (P=0.004) were the main factors affecting the changes of corneal astigmatism. ConclusionAfter 1 month of non-wearing, the flat K value of the cornea becomes flat, the steep K value remains unchanged, and the corneal astigmatism increases. There is no difference in the effect of the spherical and toric orthokeratology on corneal astigmatism. The change of corneal astigmatism is related to the patient’s age and the total duration of wearing the orthokeratology. The younger the age, the longer the duration of orthokeratology wearing, the more significant the increase of corneal astigmatism after stopping wearing the orthokeratology.