Long-term outcome of epikeratophakia

Histochemical and ultrastructural evaluation of myopic corneal lenticules based on refractive error

BACKGROUND

This study aimed to investigate cell degeneration, apoptosis, and ultrastructural differences in refractive lenticules (RL) obtained using small incision lenticule extraction (SMILE) compared with spherical equivalence (SE) refraction values.

METHODS

This study included 84 eyes from 42 patients. Patients were divided into two groups according to the SE values: those with values below 4 diopters (D) (Group 1) and above 4 diopters (D) (Group 2). Patients who did not belong to the same SE group were excluded from the study. One RL obtained from each patient was separated for light microscopy and immunohistochemical examinations, and another for transmission electron microscopy (TEM) examinations. Caspase-3 for apoptosis and alpha-smooth muscle actin (α-SMA) for cell degeneration were evaluated using immunohistochemical examinations.

RESULTS

Histological analyses showed that the density of collagen fibres was greater in Group 1 than in Group 2. Glycoaminoglycan and glycoprotein staining intensities were also higher in Group 1. TEM observations showed that Group 1 had intact cell and nuclear membranes, peripheral heterochromatin, and large nuclei, while Group 2 showed heterochromatin condensation and fragmentation, increased intracellular vacuoles, and loss of cytoplasm. Immunohistochemical analyses revealed that α-SMA and caspase-3 were significantly higher in Group 2 than in Group 1 (p < 0.001 and p < 0.001, respectively).

CONCLUSIONS

Cell degeneration and apoptosis were significantly more common in the RLs with high SE values after SMILE surgery. The tissue response induced by surgery was more severe in the RLs with high SE values. This should be considered when reusing RLs.

Increasing depth of focus with allogeneic presbyopic inlays: 3-year results

PURPOSE

To demonstrate the safety and efficacy of allogenic corneal inlays designed to increase the depth of focus (DoF) in treated eyes.

SETTINGS

Medipol University Hospital, Istanbul, Turkey.

DESIGN

Prospective case series.

METHODS

This study includes 50 eyes of 25 patients with a follow-up of 3 years. Emmetropic patients with presbyopia had implantation of allogenic corneal inlays in the nondominant eye. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and uncorrected near visual acuity (UNVA) were evaluated in all eyes. A subjective visual acuity test system (Multifocal Lens Analyzer 3.0 application) was used to analyze the DoF by measuring the defocus curves.

RESULTS

No significant difference between the treated and fellow eyes in UDVA and CDVA was found, whereas UNVA was significantly better in the treated eyes ( P = .20, P = .07, P < .01, respectively). Comparing to the preoperative CDVA, there was a 1-line decrease in CDVA in 6 (%24) patients. The mean defocus curves reveal a DoF of 1.1 diopters (D) for the untreated eye at the logMAR = 0.2 threshold. By contrast, the mean DoF of the treated eye and binocularly was 2.8 D. The areas under the curve were significantly better in the near, intermediate, and total distances in the treated eyes, whereas it was better for the far distances in the untreated eyes. All values were significant ( P = .023 total, P < .01 others).

CONCLUSIONS

Allogenic presbyopic inlay implantation may be safe and provided a clinically and statistically significant increase in the DoF leading to good far, intermediate, and near-visual acuity in emmetropic presbyopic patients.

Clinical outcomes in post-epikeratophakic eyes after removal of epikeratoplasty lenticule

Background

Assessment of the optical outcome and adverse events in post-epikeratopathic eyes after removal of the epikeratoplasty lenticule (EKPL).

Methods

This was a retrospective case-series study of patients who underwent EKPL removal between 2002 and 2020. Ten eyes were included in the analysis. We compared the clinical characteristics of the patients before surgery, 6 months after surgery, before lenticular removal, and after removal, and reported optical or ocular surface complications.

Results

We removed EKPL due to the lenticular opacity in five eyes (50%), intraocular lens (IOL) insertion (n = 4, 40%) after cataract surgery (n = 3) or in aphakic eyes (n = 1), and lenticule-induced irregular astigmatism in one eye (10%). After EKPL removal, the mean refractive power of the cornea (Km) revealed a tendency to increase. Out of nine cases, six cases showed corneal steepening and three cases revealed corneal flattening. When the keratometric readings of pre-epikeratoplasty and post-lenticular removal were compared within the same case, the average difference was 5.1 D ± 4.0 (n = 8). Complications were observed in 3 of 10 cases (excessive corneal flatness, ectatic change, and abnormal epithelial cell ingrowth) after removal.

Conclusions

The surgeon should expect the corneal refractive power to steepen or flatten in some cases with abnormal astigmatism and irregularity. Epikeratophakic eyes may exhibit serious ectatic changes, and abnormal epithelial cell ingrowth after removal of epikeratophakic lenticules.

Long-term viability of allogenic donor stroma

We report the clinical history and histopathology of the longest known postoperative course of a myopic cornea lenticule implanted via epikeratoplasty that also had been subjected to excimer laser and mitomycin. Despite the mechanical and photochemical processes the allogenic cornea stroma had sustained, it is notable that it retained structural integrity and clarity. This report affirms the potential long-term clarity and resilience of allogenic stromal cornea and supports its use as a potential stabilizing option in cornea allogenic intrastromal ring segments for keratoconus and variations thereof for other cornea disorders.

Sterile Excimer Laser Shaped Allograft Corneal Inlay for Hyperopia: One-year Clinical Results in 28 Eyes

Purpose: This study aimed to evaluate the one-year clinical results of an allograft corneal inlay (ACI) implantation in a case series of 28 hyperopic eyes of 16 patients.Methods: Patients with manifest refraction spherical equivalent (MRSE) between +1.00 and +6.00 D and having a cylindrical refraction of less than 1 D were included in this prospective study. The refractive powers of excimer laser-shaped ACIs were determined based on the refractive error of the individual subject's eyes. After the creation of a femtosecond flap, the inlays were centered on the pupillary axis. Visual acuities, refractive results, and other clinical findings were reported for the 6- and 12-month follow-up exams.Results: The mean age of the patients included in the study was 36.2 ± 12.4 years (range 22-65 years). The mean pre-operative MSRE of 3.6 ± 1.51 D decreased to 0.21 ± 0.56 D (P < .001). The uncorrected distance and near visual acuity increased from 0.33 ± 0.22 and 0.17 ± 0.13 to 0.75 ± 0.22 (P < .001) and 0.72 ± 0.19 (P < .001), respectively. The corrected distance visual acuity remained unchanged (pre-OP: 0.79 ± 0.22; post-OP: 0.80 ± 0.21; P = .916), and the corrected near visual acuity increased from 0.78 ± 0.22 to 0.84 ± 0.20 (P = .003). The mean K-value and central corneal thickness increased from 42.57 ± 0.81 D and 557.5 ± 43.0 µm to 44.8 ± 1.4 D (P < .001) and 597.1 ± 58.1 µm (P < .001), respectively. No significant postoperative complications such as diffuse lamellar keratitis, epithelial ingrowth, or decentralization were observed.Conclusion: Excimer laser-shaped ACI offers an alternative treatment modality for patients with hyperopia. Acceptable visual results and similar regression rates were observed with ACI implantation compared with other laser refractive procedures.

[Corneal transplantation in keratoconus: penetrating keratoplasty versus deep anterior lamellar keratoplasty with Melles technique]

OBJECTIVES

To evaluate the effectiveness of deep anterior lamellar keratoplasty (DALK) using Melles technique (technique B) in patients with advanced keratoconus versus a classic technique, penetrating keratoplasty (technique A).

METHODOLOGY

Retrospective descriptive comparative study between technique A and technique B in homogeneous groups.

RESULTS

Best corrected visual acuity (Snellen test decimal scale) was 0.77±0.32 for group A and 0.62±0.29 for group B, with no statistically significant differences. The mean spherical final refraction in group A was 1.73±5.1 diopters, and the mean spherical equivalent was -3.92±5.1. Technique B group gave values -2.67±4.02 diopters and -4.55±4.08 diopters, respectively, with no statistically significant differences. The residual cylinder after removal of the sutures was 4.47±2.47 diopters for group A and 3.77±1.63 for group B, with no statistically significant differences.

CONCLUSION

No statistically significant differences were found for any of the studied variables when comparing both groups using the t -test for independent samples. More studies on the homogeneity and residual stromal bed thickness could provide the key to determine whether this technique is closer to the visual acuity of penetrating keratoplasty or DALK by a descemet technique.

Refractive and visual outcomes of penetrating keratoplasty versus deep anterior lamellar keratoplasty with hydrodissection for treatment of keratoconus

PURPOSE

To compare refractive and visual outcomes of penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK) with hydrodissection for keratoconus.

METHODS

A review of medical records was performed to identify 69 subjects (77 eyes) who had undergone keratoplasty by a single surgeon. Inclusion criteria were as follows: no episodes of rejection, no adverse events or complications intraoperatively or postoperatively, a fairly normal rate of epithelialization within 2 weeks, and suture removal after 11 months. Eyes were categorized according to the procedure: 47 had undergone DALK with hydrodissection (DALK group) and 30 had undergone PKP (PKP group). A between-group comparison was performed.

RESULTS

Before suture removal, there was no statistical difference between groups in best-corrected visual acuity (BCVA) or refraction at 6 months (P > 0.05, all cases). The mean BCVA was 0.18 logarithm of the minimum angle of resolution for both groups at 12 months (just after suture removal) and 24 months postoperatively. The mean postoperative mean refractive spherical equivalents at 12 months and 2 years were -4.11 ± 3.4 diopters (D) and -4.68 ± 2.9 D, respectively, for the DALK group and -1.7 ± 2.7 D and -1.1 ± 3.6 D, respectively, for the PKP group. The DALK group was statistically more myopic at 12 and 24 months (P > 0.05, both cases). The mean refractive cylinders at 12 months and 2 years were 2.88 ± 1.60 D and 3.18 ± 1.70 D, respectively, for the DALK group and 2.80 ± 1.6 D and 3.80 ± 1.80 D, respectively, for the PKP group. The differences between groups were not statistically significant (P > 0.05, all comparisons).

CONCLUSIONS

Long-term BCVA, mean refractive spherical equivalent, and mean refractive cylinder after DALK with hydrodissection were similar to those after PKP.

LASIK surgery in children

AIMS

To report success in the treatment of high myopia in children with LASIK. To report the visual results, complications and postoperative management of children with high myopia.

METHODS

Six children (seven eyes) with high myopia were included in this series. Preoperative and postoperative refraction, visual acuity, and pachymetry were compared.

RESULTS

Six children with high myopia ranging from -5.00DS to -16DS were treated. There were three males and three females. Five children had improved refraction and visual acuity post-LASIK. Age ranged from 2 to 12 years. Five of the children had unilateral amblyopia preoperatively. One had bilateral high myopia.

CONCLUSION

High myopia in children may be treated safely and effectively with LASIK.

Ten-year follow-up of epikeratophakia for the correction of high myopia

OBJECTIVE

To determine the long-term functional results of epikeratophakia for myopic patients.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty-two patients (32 eyes; average age, 43+/-6 years) who underwent epikeratophakia surgery for high myopia. Mean preoperative myopia was -18.74+/-9.16 diopters (D; range, -7 D to -49 D). Follow-up was 12+/-2 years.

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), change in mean keratometry, visual acuity under glare conditions, BCVA versus potential acuity meter reading, and patient satisfaction with the visual outcome.

RESULTS

Mean preoperative UCVA increased from 20/800+/-20/400 (range, counting fingers-20/400) to 20/80+/-20/200 (range, 20/250-20/32) in 24 eyes. Mean preoperative BCVA of 20/32+/-20/64 increased only in five eyes, whereas six eyes had no change and 18 eyes had a more than one line loss of Snellen BCVA. Mean preoperative keratometry reading decreased from 43.67+/-0.90 D (range, 41.0-46.25 D) to 37.40+/-2.92 D (range, 29.43-47.68 D). In the presence of glare, mean BCVA decreased to 20/100+/-20/100 (range, counting fingers-20/32). Potential acuity meter (PAM) readings were significantly (P<0.05) higher than BCVA. Mean PAM reading was 20/25+/-20/100 (range, 20/100-20/16). Seven patients (11 eyes) were extremely satisfied with the operative result more than 10 years after the operation, whereas four patients (four eyes) were not satisfied at all.

CONCLUSIONS

Epikeratophakia for the correction of myopia improved UCVA significantly, but BCVA decreased. The removal of the lenticules in patients who were not satisfied with their visual acuity was uncomplicated, and acceptable vision could be achieved with either contact lenses or intraocular lens implantation.

The effectiveness of occluder contact lenses in improving occlusion compliance in patients that have failed traditional occlusion therapy

PURPOSE

Management of infants and young children with dense amblyopia, including that which results from unilateral congenital cataracts, is challenging because of noncompliance with occlusion therapy. Occluder contact lenses (OCLs) have been described to successfully improve visual acuity in patients with amblyopia. The purpose of this study was to evaluate the effectiveness of OCLs in improving occlusion compliance in infants and young children with dense amblyopia who had failed traditional occlusion therapy.

METHODS

Thirteen patients were fit in their nonamblyopic eye with OCLs provided by Wesley Jessen (Des Plaines, IL). All patients had dense amblyopia as diagnosed by a pediatric ophthalmologist. Nine of the 13 patients had deprivational amblyopia associated with unilateral aphakia, 2 patients had strabismic amblyopia, and the other 2 had mixed mechanism amblyopia. All patients had failed traditional occlusion methods. Occlusion was prescribed on a part-time basis to prevent occlusion amblyopia to the better-seeing eye. Compliance with the OCLs was determined by questioning the parents as to whether the prescribed occlusion time was accomplished.

RESULTS

Five of the 13 patients (38.4%) did not succeed in the initial 1-mo trial period because of parental difficulties with lens handling. Four patients (30.7%) achieved partial success, as they were able to wear the lens between 4 to 14 mo, at which time they learned to remove the occluder lens. The four remaining patients (30.7%) successfully wore the occluder lenses until the conclusion of the study, a time period ranging from 26 to 60 mo. No complications resulted from OCLs.

CONCLUSIONS

OCLs can provide an alternative to achieving occlusion compliance after the failure of traditional occlusion therapy in infants and young children with dense amblyopia.