SIGNIFICANCE Laser refractive surgery procedures are efficacious at correcting myopia, but they result in long-term deterioration of optical quality that affects monocular and binocular visual performance. The study shows that the optical quality of the two eyes needs to be similar to optimize binocular visual performance after surgery. PURPOSE This study aimed to systematically analyze longitudinal changes in optical quality, high- and low-contrast logMAR acuity and random-dot stereoacuity before and after three refractive surgery procedures for correcting myopia. METHODS A total of 106 subjects (laser-assisted in situ keratomileusis, 40; photorefractive keratectomy, 26; small-incision lenticule extraction, 40) with myopia and astigmatism ≤1.5 D participated in this prospective cohort-based study. All aforementioned outcome variables were measured in both eyes pre-operatively and 1 week and 1, 3, and 6 months post-operatively. RESULTS Pre-operative myopic spherical equivalent of refraction (median [25th to 75th interquartile range], −6.4 D [−8.0 to −4.2 D] for laser-assisted in situ keratomileusis, −4.3 D [−5.0 to −3.5 D] for photorefractive keratectomy, −5.5 D [−6.5 to −4.3 D] for small-incision lenticule extraction) was corrected to within ±0.75 D of emmetropia in all cohorts up to 6 months post-operatively (P < .001). Higher-order wavefront aberrations, uncorrected high- and low-contrast logMAR acuity, and stereoacuity all worsened and remained so up to 6 months post-operatively, relative to pre-operative values (P < .001). Stereoacuity worsened with both interocular average and difference in the magnitude of higher-order aberrations, whereas logMAR acuities worsened only with interocular average of these aberrations (r 2 ≥ 0.40; P < .01 for all). CONCLUSIONS Although the refractive surgery procedures tested here correct myopia, they result in a sustained (up to 6 months) loss of optical quality and spatial and depth-related visual functions post-operatively. Both interocular average and difference in the eye's optical quality seem to impair binocular visual functions after refractive surgery for myopia.

Laser refractive surgery for myopia increases the eye’s higher-order wavefront aberrations (HOA’s). However, little is known about the impact of such optical degradation on post-operative image quality (IQ) of these eyes. This study determined the relation between HOA’s and IQ parameters (peak IQ, dioptric focus that maximized IQ and depth of focus) derived from psychophysical (logMAR acuity) and computational (logVSOTF) through-focus curves in 45 subjects (18 to 31yrs) before and 1-month after refractive surgery and in 40 age-matched emmetropic controls. Computationally derived peak IQ and its best focus were negatively correlated with the RMS deviation of all HOA’s (HORMS) (r≥-0.5; p<0.001 for all). Computational depth of focus was positively correlated with HORMS (r≥0.55; p<0.001 for all) and negatively correlated with peak IQ (r≥-0.8; p<0.001 for all). All IQ parameters related to logMAR acuity were poorly correlated with HORMS (r≤|0.16|; p>0.16 for all). Increase in HOA’s after refractive surgery is therefore associated with a decline in peak IQ and a persistence of this sub-standard IQ over a larger dioptric range, vis-à-vis, before surgery and in age-matched controls. This optical deterioration however does not appear to significantly alter psychophysical IQ, suggesting minimal impact of refractive surgery on the subject’s ability to resolve spatial details and their tolerance to blur.

To compare the treatment efficacy of childhood myopia control optical interventions [spectacles, soft contact lenses (SCLs) and orthokeratology (OK) lenses], explore the consistency of treatment efficacies during the treatment period and evaluate the impact of baseline spherical equivalent refraction (SER), axial length (AL) and age on the treatment effect. A literature search of EMBASE, PubMed and Google Scholar databases identified 220 articles published between January 2000 and April 2022, which reported the treatment efficacy by differences in the SER and AL change between intervention and control groups. Thirty‐five articles were included in the analysis. Treatment effect sizes (ESs) were calculated, where more positive and negative directions indicated greater treatment efficacy for SER and AL respectively. For SER, the ESs with peripheral add design spectacles (0.66) and SCLs (0.53) were large but not significantly different between treatment types (p = 0.69). For AL, ESs with peripheral add design spectacles (−0.37), SCLs (−0.55) and OK lenses (−0.93) were large, but OK lenses had a significantly greater effect than peripheral add design spectacles (p ≤ 0.001). ESs were large during the first 12 months of treatment for all interventions [peripheral add design SCLs and OK (F ≥ 5.39, p ≤ 0.01), peripheral add design spectacles (F = 0.47, p = 0.63)] but reduced towards the end of 24–36 months of treatment. Baseline SER had an impact on the treatment effect with peripheral add design spectacles only. Optical interventions are efficacious in controlling childhood myopia progression. However, treatment effects were largest only during the first 12 months of treatment and reduced over time.

Purpose:Phenylephrine hydrochloride (PHCl), a commonly used mydriatic agent, causes a small but significant deterioration of accommodation. The relative roles of pharmacology and optics in this deterioration, however, remain unascertained. The study determined the combined impact of PHCl concentration (pharmacology) and pupil size (optics) on the static and dynamic characteristics of accommodation.Materials and Methods:A total of 16 emmetropic Indian adults viewed a high-contrast visual target that switched between 67 and 33 cm viewing distance (1.5D stimulus) with their right eye (left eye occluded using infrared transmitting filter) through natural pupils and through 8, 6, 4, and 1 mm diameter artificial pupils. This protocol was repeated once without PHCl and once each with 2.5%, 5%, and 10% PHCl. Consensual accommodation of the left eye was recorded using infrared photorefraction (60 Hz).Results:Relative to no PHCl, the horizontal pupil diameter of left eye was significantly larger (P < 0.001) and the response magnitude and peak velocity of accommodation and disaccommodation were modestly but significantly smaller (P < 0.02 for all) for all concentrations of PHCl tested. There was no significant difference in these parameters across the three drug concentrations (P > 0.4 for all). The response magnitude and peak velocity also decreased significantly with pupil diameter, at similar rates for the no PHCl and the three PHCl conditions (P < 0.001 for all).Conclusion:The reduction in accommodative performance with all drug concentrations and with pupil diameter suggests independent roles of pharmacology and optics in determining accommodative performance with PHCl. The reduction in accommodative performance is, however, modest and may be clinically irrelevant in Indian eyes.

SIGNIFICANCE: Psychophysical estimates of spatial and depth vision have been shown to be better after bilateral ReLEx small-incision lenticule extraction (SMILE) refractive surgery for myopia, relative to photorefractive keratectomy (PRK) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK). The present study provides the optical basis for these findings using computational image quality analysis.PURPOSE: This study aimed to compare longitudinal changes in higher-order wavefront aberrations and image quality before and after bilateral PRK, FS-LASIK, and SMILE refractive procedures for correcting myopia.METHODS: Wavefront aberrations and image quality of both the eyes of 106 subjects (n = 40 for FS-LASIK and SMILE and n = 26 for PRK) were determined pre-operatively and at 1-week, 1-month, 3-month, and 6-month post-operative intervals using computational through-focus analysis for a 6-mm pupil diameter. Image quality was quantified in terms of its peak value and its interocular difference, residual defocus that was needed to achieve peak image quality (best focus), and the depth of focus. RESULTS:The increase in root mean squared deviations of higher-order aberrations post-operatively was lesser after SMILE (1-month visit median [25th to 75th interquartile range], 0.34 μm (0.28 to 0.39 μm]) than after PRK (0.80 μm [0.74 to 0.87 μm]) and FS-LASIK (0.74 μm [0.59 to 0.83 μm]; P ≤ .001), all relative to pre-operative values (0.20 μm [0.15 to 0.30 μm]). The peak image quality dropped and its interocular difference increased, best focus shifted myopically by 0.5 to 0.75 D, and depth of focus widened significantly after PRK and FS-LASIK surgeries, all relative to pre-operative values ( P < .001). All these changes were negligible but statistically significant in a minority of instances after SMILE surgery ( P ≥ .01).CONCLUSIONS: Although all three refractive surgeries correct myopia, the image quality and its similarity between eyes are better and closer to pre-operative values after SMILE, compared with FS-LASIK and PRK. These results can be explained from the underlying increase in higher-order wavefront aberrations experienced by the eye post-operatively.