ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Corneal pigmented (brown) arcs were observed in two orthokeratology patients, both aged 23 years. The preorthokeratology refractive data were OD −5.25 −0.50 × 175 and OS −6.00 −0.75 × 5 for patient A and OD −3.75 −1.00 × 10 and OS −3.00 −1.25 × 175 for patient B. The time course for the development of the arcs was different not only between the two patients but also between the two eyes of patient A. For patient A, the pigmented arc was observed in the left eye 1 week after commencement of lens wear and was not observed in his right eye until a visit about 6 weeks later. For patient B, the arcs were only observed at an aftercare visit about 28 weeks after commencing lens wear. Both patients had been participating in an orthokeratology research study for about 12 months and decided to stop the treatment after completion of the study. The pigmented arcs were no longer present when they returned about 2 months later for assessment of the regression of the refractive and corneal changes induced by the procedure.

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose.The efficacy of overnight wear of four types of reverse-geometry lenses was compared. The length of time needed to achieve correction and any adverse events that occurred during the course of the study were recorded.Methods.In this prospective, randomized study, 60 subjects (18 to 35 years old) with refractive error between −1.00 to −4.00 D (cyl ≤ −1.50) wore reverse-geometry lenses overnight only. All subjects were assigned a Rinehart Reeves lens in one eye, and subsets of 20 subjects were randomly assigned a Mountford BE, DreimLens, or Contex D Series 4 lens for the contralateral eye. Visits included baseline, dispensing, 1 day, 1 week, and 1 month. Biomicroscopy, unaided visual acuity, subjective refraction, best-corrected visual acuity at high and low contrast and high and low illumination, corneal topography, and subjective rating data were collected.Results.Forty-six subjects completed the study. At 1 month, there were no significant differences between lens types in their effect on unaided visual acuity, subjective sphere, subjective cylinder, best-corrected visual acuity at high and low contrast at high illumination and low contrast at low illumination, apical corneal radius, corneal eccentricity, and subjective ratings. Between 1 week and 1 month, there was a significant improvement in subjective ratings of quality of day and night vision (p < 0.05) but no significant change in the objective measures. No significant ocular adverse events were observed during the trial.Conclusions.The lens types tested were all similarly effective in the reduction of myopic refractive error. Subjective ratings continued to improve after objective measures stabilized at 1 week. Overnight lens wear proceeded for 1 month without significant adverse reactions.

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose.To assess the changes in higher-order (third through sixth) ocular wavefront aberrations produced by Corneal Refractive Therapy (CRT; Paragon Vision Sciences, Mesa, AZ).Methods.Eighteen eyes of nine myopic subjects were fit with CRT contact lenses. Baseline subjective spherical refraction ranged from −2.25 to −6.00 D (mean ± SD, −3.33 ± 1.26 D), and baseline logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity was −0.13 ± 0.06 (20/15 Snellen equivalent). Whole-eye ocular wavefront aberrations were measured using a previously validated Shack-Hartmann aberrometer. Measurements were taken at baseline and 1 month after treatment initiation. Nine measurements per dilated subject were taken and averaged. Zernike coefficients were used to calculate the third-, fourth-, fifth-, and sixth-order root-mean-square values for each eye for both 3- and 6-mm pupil sizes, and aberrations were averaged and compared with prior baseline readings.Results.The mean (±SD) myopia reduction was 3.08 ± 0.93 D, resulting in a subjective refraction of −0.22 ± 0.38 D after 1 month of lens wear. Both logMAR uncorrected visual acuity (−0.07 ± 0.18; 20/15−Snellen equivalent) and best-corrected visual acuity (−0.14 ± 0.09) after CRT wear were not significantly different from baseline logMAR best-corrected visual acuity (paired two-tailed t-test; p = 0.41 and 0.65, respectively). Whole-eye aberrations showed a statistically significant increase in higher-order aberrations for both 3-mm (factor of 2.66; p = 0.01) and 6-mm pupils (factor of 2.50; p = 0.005). Each individual higher-order aberration also increased, ranging from a factor of 2.01 to 3.20 for 3-mm pupil sizes and 2.52 to 2.98 for 6-mm pupil sizes. Spherical-like aberrations (S4 and S6) increased by a factor of 1.79 for 3-mm pupil sizes and 2.42 for 6-mm pupil sizes. The Zernike coefficient most affected by CRT was spherical aberration (Z40), which increased from 0.084 ± 0.16 to 0.39 ± 0.16 &mgr;m (p = 0.0002) for 6-mm pupils.Conclusions.Use of current CRT lenses for the reduction of myopia increased higher-order wavefront aberrations and spherical aberration (Z40) in particular.

ISSN:1040-5488    

出版商:OVID    

年代:2003

数据来源: OVID