Endothelial cell loss rate after penetrating keratoplasty: optical versus therapeutic grafts.

Background: This study aimed to compare the rate of endothelial cell loss (ECL) after penetrating keratoplasty (PKP) for optical versus therapeutic grafts at 3-, 6-, and 12-month postoperatively. Furthermore, the study aimed to investigate postoperative graft viability and the rate of graft rejection during the first year of follow-up for both indications. Methods: This was a prospective, observational, comparative study that included patients who sought medical advice at the cornea outpatient clinic of Ain Shams University Hospitals, Cairo, Egypt. The study recruited 60 patients: group 1 included 30 transplanted corneas of 30 patients who underwent optical PKP for various indications, while group 2 included 30 transplanted corneas of 30 patients who underwent therapeutic PKP for unhealed, resistant infectious keratitis. Specular microscopy was performed for all patients at the 3-, 6-, and 12-month follow-up visits using Nidek CEM-530 specular microscopy. Postoperative clinical examinations were performed at the same follow-up visits to detect graft rejection. Results: There were no statistically significant differences between the groups concerning the postoperative timing of graft clarity or the rate of ECL at 3- and 6-months postoperatively; however, the rate of ECL was significantly greater in group 2 than in group 1 at 12-months postoperatively (P = 0.03), although the difference was small from a clinical point of view. Moreover, there was no statistically significant difference between the groups in terms of the graft rejection rate. Conclusions: Therapeutic PKP results were comparable to optical PKP with respect to graft viability, the rate of ECL, and the rate of graft rejection 1 year after grafting.

Normative Values of Corneal Spherical Aberration, Pupil Size, and Other Key Refractive and Topographic Parameters in a Large Cohort of Egyptian Cataract Surgery Candidates.

PURPOSE: To determine the spherical aberration, pupil size, and other key refractive and topographic parameters in a large cohort of Egyptian cataract surgery candidates, and to investigate any existent relations between the spherical aberration and other possibly related parameters. METHODS: This is a cross-sectional, descriptive study that was conducted at Ain Shams University Hospitals, Cairo, Egypt. The study was performed on the right eyes of 1658 cataract surgery candidates. The mean corneal spherical aberration [Z4] and the pupil diameter, both photopic [P. Pupil] and mesopic [M. Pupil], were measured by the Oculus Keratograph 3, while the white-to-white corneal diameter [WTW], average keratometric readings [average K], axial length measurements [AL] and Anterior Chamber Depth [ACD] were all obtained from the IOL Master 500. RESULTS: The mean age was 65 ± 11.3 years. The mean value of the Z4 was +0.26 ± 0.12 µm [95% Confidence Interval "CI" (0.2570-0.2681)]. The mean values of the measured parameters were: P. Pupil 2.43 ± 0.87 mm [95% CI (2.3867-2.4700)], M. Pupil 4.61 ± 0.91 mm [95% CI (4.5683-4.6557)], WTW 11.72 ± 0.44 mm [95% CI (11.6969-11.7394)], average K 43.89 ± 1.89 D [95% CI (43.7938-43.9701)], AL 24.23 ± 2.21 mm [95% CI (24.1118-24.3166)], and ACD 3.16 ± 0.43 mm [95% CI (3.1414-3.1827)]. Weak statistically significant correlations were found between the Z4 and each of age (r = 0.049, p = 0.044), average K (r = 0.191, p < 0.001), and ACD (r = 0.122, p < 0.001). Multivariate analysis showed weaker relations between Z4 and both average K (beta coefficient= 0.091) and ACD (beta coefficient= 0.130), with an r2 = 0.024. CONCLUSION: This is the first normative data report of corneal spherical aberration [Z4], pupil size, and related refractive and topographic parameters in an old Egyptian population. The detected correlations have a weak clinical relevance and negate the existence of significant relations between the Z4 and the studied refractive and topographic parameters.

Relation of Corneal Astigmatism with Various Corneal Image Quality Parameters in a Large Cohort of Naïve Corneas.

PURPOSE: To investigate the relationship between corneal astigmatism and corneal image quality parameters (i.e., root mean square [RMS] of some major corneal higher order aberrations [HOAs] "namely RMS of coma aberrations, RMS of trefoil aberrations, and RMS of spherical aberration [RMS-SA]" and Strehl ratio [SR] of point spread function [PSF]) by using the Sirius topographer (CSO Italia, Florence, Italy). PATIENTS AND METHODS: This cross-sectional study used the Sirius topographer to evaluate the naïve corneas of right eyes (n = 1,356). The study included three groups which were based on the mean anterior corneal astigmatism value (group 1, <1 D; group 2, 1-2 D; and group 3, >2 D). RESULTS: The corneal astigmatism showed statistically significant (yet narrow clinical) differences among the groups regarding all the examined parameters (P<0.001), except for the RMS-SA (which was statistically insignificant among the three groups). Correlation coefficients were weak between the corneal astigmatism and HOAs (correlation coefficient "r" not reaching 0.2 with any of the evaluated HOAs). CONCLUSION: Significant differences existed among the astigmatic groups regarding corneal HOAs, but the mean values were very close. The deduced relations between corneal astigmatism and corneal image quality parameters had limited clinical relevance. Thus, the corneal astigmatism should be evaluated separately from corneal image quality parameters, either when deciding between refractive correction modalities (customized versus optimized ablation techniques) or when evaluating corneal image quality of a naïve cornea.

Effect of lens thickness and nuclear density on the amount of laser fragmentation energy delivered during femtosecond laser-assisted cataract surgery.

PURPOSE: To study the influence of lens thickness and nuclear density on the amount of laser fragmentation energy delivered during femtosecond laser-assisted cataract surgery. SETTING: Ain Shams University and Al-Watany Eye Hospital, Cairo, Egypt. DESIGN: Retrospective case series. METHODS: This study included eyes of patients with primary cataract of different nuclear densities that had femtosecond laser-assisted cataract surgery using the Catalys Precision system. Variables studied included preoperative lens thickness measured by spectral-domain optical coherence tomography, nuclear density using the Lens Opacities Classification System III, pupil size, laser fragmentation energy, total laser energy, and transversal ultrasound time (Ellips FX). Patients were divided according to the preoperative lens thickness as follows: lens thickness more than 4.8 mm (Group 1) and lens thickness 4.8 mm or less (Group 2). RESULTS: The study included 192 eyes of 120 patients. The amount of laser energy for fragmentation was statistically significantly higher in Group 1 than in Group 2 (5.9 J ± 1.5 [SD] versus 4.5 ± 1.8 J) (P < .001). Laser fragmentation energy and total laser time had a strong positive correlation with lens thickness (r = 0.53, P < .001) but not with nuclear density or pupil size. Lens thickness was positively correlated with age (r = 0.42, P < .001) but not with nuclear density. CONCLUSIONS: The preoperative lens thickness, not density, determined the amount of laser energy delivered. The laser might deliver unnecessary energy for softer and thicker nuclei while delivering less energy for thinner but harder nuclei.