Single intrastromal corneal ring segment implantation using the femtosecond laser after radial keratotomy in a keratoconic patient

Clinical, tomographic, and topometric outcomes of progressive thickness intracorneal ring segment implantations in duck-type keratoconus

Purpose

To evaluate the visual, refractive, tomographic, and topometric outcomes of progressive thickness intracorneal ring segment (PT-ICRS) implantation in duck-type keratoconus.

Methods

This retrospective study included eyes with oval (duck-type) keratoconus treated with PT-ICRS implantation. After the femtosecond laser tunnel creation, one PT-ICRS (Keraring AS 5 with 160° arc length) was implanted along the ectatic, inferior half of the cornea. Data of uncorrected and corrected distance visual acuity (UDVA and CDVA), refraction, asphericity (Q value), and keratometry (K) were compared pre- and postoperatively. Additionally, changes in the topometric indices of corneal irregularity were also evaluated after PT-ICRS implantation.

Results

Thirty-one eyes of 30 patients were included in the study with a mean follow-up time of 9.06 months (ranging between 6 and 18 months). UDVA improved from 0.85 ± 0.36 to 0.27 ± 0.14 logMAR (P = 0.001), and CDVA improved from 0.37 ± 0.22 to 0.13 ± 0.11 logMAR (P = 0.001). The mean spherical error decreased from -3.66 ± 2.60 to -1.60 ± 1.42 D (P = 0.001), and the mean cylindrical error decreased from -4.91 ± 2.65 to - 1.41 ± 1.31 D (P = 0.001). All topographic parameters measured from the anterior cornea demonstrated statistically significant improvements after PT-ICRS implantation (P = 0.001). K mean, K maximum, corneal astigmatism, and Q value showed a significant decrease. Besides the index of height asymmetry, all topometric indices were significantly reduced after PT-ICRS implantation. There were no loss of lines and no complications.

Conclusion

PT-ICRS implantation in duck-type keratoconus is an effective and safe treatment. This intervention improves the visual acuity, refractive error, topographical, and topometric parameters significantly by decreasing both eccentricity and steepness of the cone.

Effects of corneal cross-linking on contrast sensitivity, visual acuity, and corneal topography in patients with keratoconus

PURPOSE

To assess the effects of corneal collagen cross-linking (CXL) on contrast sensitivity (CS), visual acuity, and corneal topography investigating possible predictors of efficacy.

METHODS

Sixty-eight eyes of 34 patients with progressive keratoconus were enrolled in this prospective study. CXL was performed in one eye and the other eye was left untreated as a control. CS, best spectacle-corrected visual acuity (BSCVA), simulated keratometry in the steepest meridian (SimK-s), mean power in the central 3-mm zone (C-MP), mean power in the paracentral 3- to 5-mm zone (P-MP), maximum keratometric power in the central zone (C-Kmax), and maximum keratometric power in the paracentral zone (P-Kmax) were evaluated at baseline, 40 days, 3 months, 6 months, 1 year, and after 2 years of follow-up.

RESULTS

Treated eyes showed an improvement (P < 0.001) of +0.16 logCS and -0.16 logarithm of the minimum angle of resolution (logMAR) and a reduction in SimK-s of -0.61 diopter (D), C-Kmax -1.11 D, P-Kmax -0.99 D, C-MP -0.39 D, and P-MP -0.30 D. Of the treated eyes, 43.3% had a decrease in C-Kmax greater than 1 D, 50% by 0 to 0.99 D, and 6.7% had an increase of up to +0.89 D. Treated eyes with keratometric apex in the central 3-mm zone (CKA) improved BSCVA -0.19 logMAR and CS +0.19 logCS; whereas in treated eyes with paracentral keratometric apex (PKA), the improvement was -0.13 logMAR and +0.16 logCS.

CONCLUSIONS

CXL with riboflavin and UV-A improved CS and inhibited the progression of keratoconus. As a predictor of treatment efficacy, eyes with CKA showed greater improvement in BSCVA after CXL when compared with eyes with PKA.

PROSE treatment of corneal ectasia

PURPOSE

Prosthetic replacement of the ocular surface ecosystem (PROSE) uses custom designed and fabricated prosthetic devices in a treatment that restores vision, supports healing, reduces symptoms and improves quality of life in patients with complex corneal disease. We report the success rate for PROSE treatment of corneal ectasia.

METHODS

Records of 59 patients with corneal ectasia seen in consultation over 6 months were reviewed. Candidacy for treatment, topographic indices, change in visual acuity, achievement of satisfactory fit, device wear status and change in visual function at 6 months were recorded.

RESULTS

Sixteen eyes were non-candidates because conventional correction was adequate. Trial devices were inserted but not dispensed for 13 eyes. No eyes were excluded for severity of ectasia. In the remaining 89 eyes, satisfactory fit was achieved and a device was dispensed. Twenty-one eyes (15 patients) had undergone penetrating keratoplasty. Device wear at 6 months was documented in 78/89 eyes (88%). NEI VFQ-25 score improved 27.6 points (p<0.001) on a 100 point scale in patients wearing a device at 6 months.

CONCLUSION

All candidate eyes with corneal ectasia could be fitted with a PROSE device. PROSE treatment has a high success rate when measured by ability to achieve satisfactory fit, impact on visual acuity and 6 month data on both rate of continued wear and impact on visual function. PROSE treatment is an alternative to penetrating keratoplasty for patients with corneal ectasia who are contact lens intolerant.