Comparison of goblet cell density after femtosecond laser and mechanical microkeratome in LASIK.

PURPOSE: To study the effect of the LASIK procedure performed with a femtosecond laser and a manual microkeratome on the conjunctival goblet cell and epithelial cell populations. METHODS: In this prospective, nonrandomized, masked study, 64 eyes undergoing LASIK were included: 30 with the Moria M2 (M2) microkeratome and 34 with the IntraLase femtosecond laser (IL). The preoperative spherical equivalent was -2.0 +/- 3.8 D in the M2 group and -3.1+/- 3.1 D in the IL group. The time that the suction ring was applied on the eye was registered, and goblet cell density (GCD), epithelial cell morphology, and inflammatory cells were evaluated by conjunctival impression cytology, before and after the surgery. RESULTS: All the patients in both groups showed a decrease in GCD after LASIK (P < 0.001) that recovered after 6 months. At 1 week, 1 month, and 3 months, GCD was lower with IL than with M2 (P < 0.019, P < 0.001, and P < 0.024, respectively). The mean period that the suction ring was applied was longer in the IL than in the M2 group (P < 0.001). There was a high correlation between the decrease in GCD and the suction time (R = 0.8), and the preoperative spherical equivalent (R congruent with 0.4). CONCLUSIONS: Impression cytology showed a greater reduction in goblet cell populations after IL than after M2, probably because of the length of time that the suction ring exerted pressure on the conjunctiva. These changes in the goblet cells may contribute to the development of the ocular surface syndrome after LASIK procedures.

Effect of suction ring application during LASIK on goblet cell density.

PURPOSE: To study the effect of LASIK surgery on conjunctival goblet cells as one of the proposed mechanisms for dry eye occurring after LASIK. METHODS: This prospective study included 22 eyes (11 patients) that underwent LASIK for the correction of myopia. Three pairs of samples were taken from the bulbar conjunctiva of each eye. The first pair was taken preoperatively before application of the suction ring. The second and third pairs were taken from the same sites at 1 week and 1 month consecutively. The first site was at 12 o'clock and the second at the inferotemporal quadrant between 7 and 8 o'clock. Time of suction was recorded. RESULTS: Preoperatively, mean goblet cell density was 424 +/- 105 cells/mm2 (range: 284 to 630 cells/mm2). All postoperative samples showed a statistically significant decrease in goblet cell count: 216 +/- 81 cells/mm2 (range: 40 to 325 cells/mm2) at 1 week and 218 +/- 99 cells/mm2 (range: 50 to 396 cells/mm2) at 1 month. Other parameters of conjunctival impression cytology were normal. The difference between the samples in the inferior conjunctiva preoperatively and 1 week postoperatively was greater than that of the superior conjunctiva. Recovery rate in both sites was similar and the damage did not correlate with the duration of suction. CONCLUSIONS: The application of the microkeratome suction ring induced changes in the perilimbic conjunctiva. These changes contribute to the pathology of dry eye. Goblet cell count remains affected at 1 month postoperatively.

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.

Preliminary results of intrastromal corneal ring segment implantation to treat moderate to severe keratoconus.

PURPOSE: To present our preliminary experience with implantation of Ferrara intrastromal corneal ring segments (ICRS) in keratoconus patients. SETTING: Magrabi Eye and Ear Center, Jeddah, Saudi Arabia. DESIGN: Case series. METHODS: This study comprised patients diagnosed with primary keratoconus who had ICRS implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities were recorded. The change in manifest refraction spherical equivalent (MRSE), mean refractive cylinder, average simulated keratometry (K), and topographic cylinder from preoperatively to 6 months postoperatively was analyzed, and complications were noted. The t test was used to compare 2 independent means and the Wilcoxon signed-rank test, to compare nonparametric data. RESULTS: By 6 months postoperatively, the CDVA was unchanged in 27% of cases and had improved between 1 line and 6 lines in 64% of cases; 9% of cases lost 1 or 2 lines. There was a decrease in the following mean values: MRSE (-3.60 diopters [D] ± 3.10 [SD] to -2.52 ± 3.10 D; P = .209); refractive cylinder (5.18 ± 2.10 D to 2.90 ± 2.50 D; P = .000); simulated K (51.16 ± 5.60 D to 48.11 ± 3.60 D; P = .000); topographic cylinder (5.30 ± 2.80 D to 3.80 ± 3.20 D; P = .000). For cases with a 24-month follow-up, stability was similar for all parameters. Intraoperative or postoperative complications occurred in 13% of cases; all were managed without clinically significant visual loss. CONCLUSION: Implantation of ICRS resulted in reasonable refractive and visual outcomes in a wide spectrum of keratoconus cases. FINANCIAL DISCLOSURE: The author has no financial or proprietary interest in any material or method mentioned. Additional disclosure is found in the footnotes.