Corneal Aberrations, Contrast Sensitivity, and Light Distortion in Orthokeratology Patients: 1-Year Results

Abstract

Purpose. To evaluate the corneal higher-order aberrations (HOA), contrast sensitivity function (CSF), and light distortion (LD) in patients undergoing orthokeratology (OK). Methods. Twenty healthy subjects (mean age: 21.40 ± 8 years) with mean spherical equivalent refractive error M = −2.19 ± 0.97 D were evaluated at 1 day, 1 month, and 1 year after starting OK treatment. Monocular LD, photopic monocular CSF, and corneal HOA for 6 mm pupil size were measured. Results. LD showed an increase after the first night (p < 0.05) and recovery to baseline after 1 month, remaining stable after 1 year (p > 0.05). Spherical-like, coma-like, and secondary astigmatism HOA RMS increased significantly (p ≤ 0.022) from baseline to 1-month visit, remaining unchanged over the follow-up. Contrast sensitivity for medium frequencies (3.0, 4.24, and 6.00 cpd) was significantly correlated with LD parameters at baseline (r ≤ −0.529, p < 0.001). However, after 1 year of treatment, this correlation was only statistically significant for 12 cpd spatial frequency (r ≤ −0.565, p < 0.001). Spherical-like RMS for 6 mm pupil size correlated with irregularity of the LD (r = −0.420, p < 0.05) at the 1-year visit. Conclusion. LD experienced by OK patients recovers after one month of treatment and remains stable in the long term while optical aberrations remain significantly higher than baseline.

Light disturbance with multifocal contact lens and monovision for presbyopia

“…While center-near MFCL induces large amounts of negative SA, center-distance MFCL induce an increase in positive SA [31,36]. Moreover, it has been reported that higher amounts of positive SA significantly increase LD, while a lower increase or even decrease can be found with negative SA [39][40][41]. On one level, this may explain the differences observed in LD between dominant (center-distance design) and non-dominant (center-near design).…”

Influence of Overnight Orthokeratology on Corneal Surface Shape and Optical Quality

“…Rah and his colleagues [ 23 ] showed that there was no difference in quality of life indices between refractive surgery and orthokeratology by using the National Eye Institute Refractive Error Quality of Life instrument (NEI-RQL 42). There are also a lot of studies hold that the overnight orthokeratology can induce significant changes in optical quality [ 8 , 24 , 25 ].…”

Orthokeratology in Moderate Myopia: A Study of Predictability and Safety

“…[15,16,[18][19][20] A concern with OK lenses is loss of contrast; however, in this series contrast sensitivity (and visual acuity) did not deteriorate either in the OK group or the control group after lens wear. [22] A study by Tang et al measuring contrast sensitivity under both photopic and mesopic conditions corroborated this finding. [23] Corneal flattening by a mean of 1.2 D was observed by four months, with maximum flattening after initial overnight use.…”