Greater higher order aberrations induced by toric orthokeratology versus soft toric multifocal contact lens wear

Comparison of myopic control between orthokeratology contact lenses and defocus incorporated multiple segments spectacle lenses

Purpose: The purpose of this study was to compare the differences in myopic control effects between orthokeratology (OK) contact lenses and defocus incorporated multiple segments (DIMS) spectacle lenses. Methods: A retrospective cohort study was conducted that included patients who had received OK lens, DIMS spectacle lens or single-vision spectacle treatments. A total of 54 eyes from 27 individuals, 38 eyes from 19 individuals and 42 eyes from 21 individuals were enrolled into the OK lens, DIMS and control groups, respectively. The primary outcomes were the changes in the spherical equivalent refraction (SER) and axial length (AXL) among the groups. A repeated-measure ANCOVA was adopted to calculate the SER progression and AXL elongation of the OK lens group compared with the DIMS group. Results: The difference in the SER progression was clinically non-significant in the OK lens group compared with the DIMS and control groups (P = 0.001). The total AXL elongation results were similar between the OK lens and DIMS groups, but these were lower than in the control group (P = 0.005). The repeated-measure ANCOVA revealed that the SER progression difference during the study interval was clinically non-significant in the OK lens group when compared with the DIMS group (P = 0.028). The AXL elongation results between the OK lens and DIMS populations did not illustrate a significant difference (P = 0.607). In a subgroup analysis of moderate astigmatism, better AXL control was observed in the DIMS subgroup compared with the OK lens subgroup (P = 0.016). Conclusions: The OK lens demonstrated a clinically non-significant effect on the SER and AXL controls compared with the DIMS spectacle lens.

The effect of back optic zone diameter on relative corneal refractive power distribution and corneal higher-order aberrations in orthokeratology

PURPOSE

To compare axial elongation, relative corneal refractive power (RCRP) distribution within the pupillary diameter, and corneal higher-order aberrations (HOAs) in myopic children wearing orthokeratology (ortho-k) lenses with different back optic zone diameters (BOZD).

METHODS

Children aged 8-11 years were fitted with 5.0 or 6.2 mm-BOZD ortho-k lenses (groups A and B, respectively). Axial length (AL) and corneal topography were measured at baseline and during the annual visit. RCRP and corneal HOAs were compared between the two groups after one-year treatment. Multivariate linear regression analysis was performed to determine the association between AL elongation and RCRP parameters, corneal HOAs, and other variables between the groups.

RESULTS

After one-year treatment, axial elongation was slower in group A than in group B, with a difference of 0.15 mm. Children in group A showed smaller treatment zone size, smaller 3/4X value (describing the distance from the apex RCRP profile rising to its three-quarter-peak level), greater RCRP sum value within the pupillary area, and higher increases in corneal total HOAs and horizontal coma (Z₃¹). AL elongation was significantly correlated with baseline age, baseline spherical equivalent refraction (SER), treatment zone size, and 3/4X value.

CONCLUSIONS

Ortho-k lenses designed with smaller BOZD increased myopia control efficacy, induced a steeper distribution of the RCRP profile within the pupillary diameter, and induced greater increases in corneal total HOAs and horizontal coma (Z₃¹). Lens-induced RCRP profile within pupillary diameter, rising to its three-quarter-peak level at a smaller distance, may show a better myopia control effect.

Clinical Outcomes of a Randomized Trial with Contact Lenses for Astigmatic Myopia Management

SIGNIFICANCE

There are limited treatment options for myopia management of patients with moderate to high astigmatism. This work directly compares toric orthokeratology and soft toric multifocal lenses to show differences in visual acuity and patient satisfaction that could impact clinical care. Toric orthokeratology caused reduced visual acuity but was preferred subjectively for vision and overall.

PURPOSE

This study aimed to quantify objective and subjective clinical differences between toric orthokeratology and soft toric multifocal contact lenses in the same cohort of myopic wearers with moderate to high astigmatism.

METHODS

Thirty adults with refractive myopia (plano to -5.00 D) and astigmatism (1.25 to 3.50 D) were fitted empirically with both toric orthokeratology and soft toric multifocal contact lenses. Participants wore lenses for 10 days in random order, separated by a 14-day washout period. High-contrast visual acuity, low-contrast visual acuity, and glare logMAR visual acuity were measured. Surveys ascertained subject preference for comfort, vision, handling, and cost. Friedman, Wilcoxon signed rank, and χ2 tests were performed.

RESULTS

A subset of participants (n = 17) who achieved good vision with both lens types was analyzed. High-contrast and glare acuity with toric orthokeratology were reduced by one line compared with soft toric multifocal lenses (both 0.00 vs. -0.10, P ≤ .003). Participants preferred toric orthokeratology for vision ( P ≤ .03) but soft toric multifocal lenses for handling ( P ≤ .006). When forced to choose between lens types, participants preferred toric orthokeratology for vision and overall (both P ≤ .007).

CONCLUSIONS

Participants who achieved good vision with both lens types preferred toric orthokeratology over soft toric multifocal lenses, despite reduced high-contrast and glare visual acuity. Further research is needed to understand the relationship between visual performance and patient satisfaction.

Peripheral Refraction With Toric Orthokeratology and Soft Toric Multifocal Contact Lenses in Myopic Astigmatic Eyes

Purpose

There has been little research on myopia management options for patients with astigmatism. This study quantified changes in peripheral refraction induced by toric orthokeratology (TOK) and soft toric multifocal (STM) contact lenses.

Methods

Thirty adults with refractive error of plano to −5.00 D (sphere) and −1.25 to −3.50 D (cylinder) were enrolled. Cycloplegic autorefraction was measured centrally, ±20 degrees, and ±30 degrees from the line of sight nasally (N) and temporally (T) on the retina. Measurements were made at baseline, after 10 ± 2 days of TOK wear (without lenses on eye), and after 10 ± 2 days of STM wear (with lenses on the eyes) and compared with repeated-measures analysis of variance.

Results

Compared to baseline, TOK induced a myopic shift in defocus (M) at all locations (all P < 0.01), but STM only induced a myopic shift at 20 T in both eyes and 30 N/T in the left eye (all P < 0.01). TOK resulted in more myopic defocus than STM at all locations (all P < 0.05) except 20 T in the left eye. TOK induced more J₀ astigmatism at all locations (all P < 0.02), except 20 N in the right eye; J₀ with STM was different than baseline at 20 N in both eyes and 30 N in the right eye (all P < 0.02). TOK induced more J₀ astigmatism than STM at all locations (all P < 0.01), except 20 T in the left eye. Differences in J₄₅ astigmatism, when significant, were clinically small.

Conclusions

Greater amounts of peripheral myopic defocus and J₀ astigmatism were induced by TOK compared to STM, which may influence efficacy for myopia management.