Corneal Stability following Hyperopic LASIK with Advanced Laser Ablation Profiles Analyzed by a Light Propagation Study

Hyperopic LASIK and postoperative corneal steepness: revisiting the 49-diopter limit

PURPOSE

To compare corrected distance visual acuity (CDVA) outcomes of hyperopic laser in situ keratomileusis (LASIK) with a postoperative corneal steepness above vs below 49 diopters (D).

SETTING

Care-Vision Laser Centers, Tel-Aviv, Israel.

DESIGN

Retrospective study.

METHODS

This study included consecutive patients who underwent hyperopic LASIK between January 2013 and December 2019. Hyperopic patients were divided into 2 groups based on postoperative corneal steepness with steep corneas defined >49.0 D and the control group ≤49.0 D. Adjustments were performed to account for differences in baseline and intraoperative parameters.

RESULTS

Overall, 1703 eyes of 1703 patients were included. Mean age was 48.3 ± 10.0 years, and 45.3% were male. Preoperatively, the steep group (2.4%, n = 41/1703) had steeper mean (44.6 D vs 43.1 D, P < .001) and steep (45.1 D vs 43.5 D, P < .001) keratometry, worse logMAR CDVA (0.07 vs 0.04, P = .02), and higher sphere (4.9 D vs 2.9 D, P < .001). Intraoperatively, they had a higher spherical treatment (4.6 D vs 2.8 D, P < .001). After hyperopic LASIK, the steep group had worse logMAR CDVA (0.10 vs 0.06, P = .01). However, after accounting for differences in baseline and spherical treatment, no significant differences were found in postoperative logMAR CDVA (0.06 vs 0.06, P = .99). The factors that remained associated with worse postoperative CDVA were higher spherical treatment (0.01 logMAR per 1 D, P < .001) and preoperative CDVA (0.60 logMAR per 1.00 logMAR, P < .001).

CONCLUSIONS

Postoperative corneal steepness greater than 49 D is not associated with worse visual outcomes after hyperopic LASIK. However, lower preoperative visual potential and higher spherical treatment applied are associated with worse outcomes. The 49 D cutoff should be revisited.

Femtosecond LASER-Assisted Double Intraocular Lens Exchange in Nanophthalmic Eyes

Introduction

Though patients with nanophthalmos frequently endure decreased quality of vision with contact lenses or spectacles, refractive surgery is generally an inadequate alternative due to the associated high refractive error. A refractive lens exchange (RLE) is an alternative option but is technically challenging, requiring accuracy in biometry measurements and procedures.

Case Presentation

This case discusses a 27-year-old female with nanophthalmos (axial lengths 17.6 mm and 17.4 mm, right and left eyes, respectively) who underwent a femtosecond laser-assisted (FLA) RLE with simultaneous implantation of a monofocal and a Sulcoflex trifocal (Rayner, Britain) lens in each eye. Preoperative cycloplegic refraction was +11.50/-0.75 × 145 and +12.00/-1.00 × 35 in the RE and LE, respectively. Best-corrected visual acuity (BCVA) at distance and near in the RE and LE was 6/7.5 and J1, 6/8.5 and J2, respectively. Uncorrected visual acuity (UCVA) was >6/120 and >J14 for each eye. FLA RLE was performed in the RE, then in the LE 2 weeks later. In each eye, a monofocal (44.0 D, RE, and LE) and a Sulcoflex trifocal lens (both implants, Rayner, Britain) were implanted in one procedure. Distance and near UCVA measured 6 weeks post-op RE and 1-month post-op LE at 6/8.5 and J1 in the RE, 6/10 and J1 in the LE. The RE and LE refraction and BCVA were +0.50/-1.00 × 115, 6/7.5, and plano/-1.00 × 55, 6/8.5, respectively. The post-op outcomes were uneventful.

Conclusion

A single procedure concurrently implanting a monofocal and Sulcoflex trifocal intraocular lens in nanophthalmic eyes resulted in an excellent UCVA. This procedure can be considered esthetic and reconstructive as it significantly improves patient appearance and function.

Early Outcomes of Two Treatment Modes of PresbyLASIK: Monocular vs. Micro-Monovision

PURPOSE

To report the visual, refractive and subjective outcomes of presbyLASIK for the correction of presbyopia.

METHODS

Monocular (20 eyes) or micro-monovision (12 eyes) presbyLASIK was performed on a total of 32 eyes in 16 patients (50% female, average age 55±4.6 years) using the Zeiss VisuMax 400Hz femtosecond and Schwind Amaris 1050RS excimer laser platform. Predictability, safety and efficacy were assessed and compared at 4-6 weeks, 3 months and 6 months. Results were considered significant if P < 0.05.

RESULTS

For monocular treatments, average postoperative spherical equivalent (SE) was 0.1±0.1 D and -0.86±0.5 D at 4-6 weeks postoperatively for distance and near eyes respectively; 90% eyes achieved SE ±1.0 D of the target. Postoperative binocular uncorrected distance (UDVA), intermediate (UIVA) and near visual acuity (UNVA) were -0.03±0.1 LogMAR (20/20), 0.09±0.26 LogMAR (N4) and 0.29±0.11 LogMAR (N6) respectively with 90% patients achieving binocular UDVA of 20/20 or better. For micro-monovision treatments, average postoperative SE was -0.33±0.51 D and -1.60±0.78 D at 4-6 weeks postoperatively for distance and near eyes respectively; 100% eyes achieved SE ±1.0 D of the target. Postoperative binocular UDVA, UIVA and UNVA were 0.05±0.16 LogMAR (20/20), -0.02±0.10 LogMAR (N3) and 0.23±0.08 LogMAR (N5) respectively with 67% patients achieving binocular UDVA of 20/20 or better.

CONCLUSION

Monocular and micro-monovision presbyLASIK are both effective options for the treatment of presbyopia. Monocular treatments are more likely to be well tolerated by patients who prefer to preserve exceptional distance vision, while micro-monovision treatments may be better suited to patients who can tolerate compromises in distance vision in order to attain greater intermediate vision function.

[Refractive surgery for hyperopia]

Hyperopia is a refractive error in which light is focused behind, instead of on, the retina. Clear vision can be obtained by accommodation, but in the long run, this results in eye strain. Hyperopia can be classified as low [≤2.00 diopters (D)], moderate (2.00-4.00 D) and high (>4.00 D). Detailed preoperative evaluation is necessary and essential to obtain good postoperative results. Various surgical techniques can be proposed to correct this ametropia. The main techniques used act either by modifying the corneal curvature with the Excimer laser or by implanting a phakic intraocular lens. The anatomical peculiarities of the hyperopic eye (small corneal diameter, short axial length, narrow anterior chamber or large kappa angle) make refractive surgery for hyperopia a considerable challenge. Large optical ablation zones now allow correction of high hyperopia by reducing the risks of optical aberrations and regression. The patient must be informed and understand the postoperative course, which differs from that of surgery for myopia.

Phakic intraocular lens implantation for the correction of hyperopia

The prevalence of myopia is much higher than hyperopia. Hence, there are relatively few studies investigating phakic intraocular lens (pIOL) implantation for the correction of hyperopia. This review aimed to summarize the available relevant literature on the efficacy and safety of pIOL implantation for the correction of hyperopia and hyperopic astigmatism. At present, two types of pIOLs are used to correct hyperopia and hyperopic astigmatism: anterior chamber iris-fixated pIOLs and posterior chamber implantable collamer lenses. Both have been found to be safe and effective. No serious events (eg, retinal or choroidal detachment, endophthalmitis) were reported in the reviewed articles. Implantation of pIOLs might be the optimal refractive surgery for the correction of high hyperopia.

Preliminary effects of treating the half of high latent hyperopia on refractive and visual results of femtosecond laser-assisted in situ keratomileusis in subjects with hyperopia

BACKGROUND

To evaluate the preliminary effects of treating the half of high latent hyperopia on refractive and visual outcomes of femtosecond laser-assisted in situ keratomileusis (LASIK) in young subjects with hyperopia.

METHODS

This non-randomized comparative study includes 120 eyes of 60 subjects who underwent femtosecond LASIK to correct hyperopia. Group 1 (n = 60) includes subjects with ≤ 1D algebraic difference (DRSE) between cycloplegic (CRSE) and manifest (MRSE) refraction spherical equivalents and was treated by entering manifest refraction values. Group 2 includes subjects with > 1D DRSE and was treated by entering the mean manifest and cycloplegic refraction values. Refractive and subjective outcomes obtained at the 1-, 3-, and 6-month postoperative visits were compared.

RESULTS

The mean age of the subjects was 26.2 ± 3.5 and 26.2 ± 5.2 years for Group 1 and Group 2, respectively. The male-to-female ratios were 10/10 in both groups. Demographic values of the groups were similar (p > 0.05). Preoperative MRSE values were similar (p = 0.924), while CRSE and DRSE values were significantly higher in Group 2 (p < 0.001). At the 1- and 3-month postoperative visits, MRSE was higher and uncorrected distance visual acuity (UDVA) was lower in Group 2 (p < 0.001). Subjective visual parameters and quality of vision scores were also worse in Group 2 during these visits (p < 0.001); however, at the 6-month visit, all outcomes for Group 2 improved, and MRSE, UDVA, some subjective visual parameters, and quality of vision scores became similar between groups (p > 0.05).

CONCLUSION

At the 6-month visit after treating the half of > 1D latent hyperopia with femtosecond LASIK, refractive and visual outcomes like MRSE, UDVA, subjective visual parameters, and quality of vision scores become similar to those obtained in ≤ 1D latent hyperopia.

Stability of corneal topography and aberrometry after hyperopic laser in situ keratomileusis with a 500-Hz excimer laser platform: A 3-year follow-up study

PURPOSE

The aim of this study is to analyze the long-term stability of the corneal topography, the functional optical zone, and the refractive stability throughout 3 years following laser in situ keratomileusis surgery for hyperopia using a 500-Hz excimer laser system.

METHODS

This retrospective consecutive observational case series study comprised 66 eyes that underwent laser in situ keratomileusis to correct hyperopia with a postoperative follow-up of 3 years. Laser in situ keratomileusis procedures were performed using the SCHWIND Amaris 500-Hz excimer laser. Main outcomes measured were stability of the functional optical zone at corneal topography and corneal aberrometry.

RESULTS

Statistically significant differences were found in simulated keratometry (K2 (steep meridian) and Km (mean keratometry)) between 3 and 36 months postoperatively (p ⩽ 0.01); these differences disappeared at 12 and 36 months (p ⩾ 0.18). No statistically significant changes were observed in the horizontal and vertical diameter of the functional optical zone throughout the whole follow-up (p ⩾ 0.07). A statistically significant difference was found in the spherical aberration between 3 and 36 months (p = 0.02); this difference disappeared when compared between 12 and 36 months (p = 0.72). Statistically significant correlations were detected between the vertical functional optical zone and coma root mean square (r = -0.510, p < 0.01) and between the vertical functional optical zone and spherical aberration (r = 0.441, p = 0.02) 36 months after surgery.

CONCLUSION

Following 3 years of hyperopic laser in situ keratomileusis with a 500-Hz Amaris excimer laser, keratometry, functional optical zone, and corneal aberrations remain stable from 1 year after surgery. Topographical regression is not observed in hyperopic laser in situ keratomileusis with this excimer laser technology from 1 year after surgery.