Effect of ocular biometric factors on corneal biomechanical properties.

PURPOSE: To evaluate the effects of ocular biometric variables on corneal biomechanical properties. METHODS: A total of 102 eyes of 102 participants were enrolled in this cross-sectional study. The axial length (AL) was determined by an IOL master 500 and measurements of corneal biomechanical properties were performed using Corvis ST, integrated with pentacam results. RESULTS: Aging and corneal steepening were associated with less corneal deformability and higher movement of the entire eye. Longer AL corresponded with greater deformability and lower corneal viscous damping properties and less whole eye movement (all P-values < 0.05). In contrast to mean keratometry (Mean K) and corneal diameter, anterior chamber depth (ACD) and AL have a significant effect on corneal biomechanical parameters. Corneal biomechanical index (CBI) was not significantly correlated with any of biometric parameters. Stress-strain index (SSI) was significantly correlated with age (r = 0.470), spherical equivalent (SE) (r = 0.537), AL (r = -0.534) and ACD (r = -0.316) (all P-values < 0.001). CONCLUSIONS: In normal individuals, several parameters such as age, ACD, AL and Mean K have a great impact on corneal biomechanical properties; thereby, these effects should be taken into account prior to interpretation of corneal biomechanics, particularly in older ages and eyes with longer AL and steeper cornea.

Topical Tacrolimus as Adjuvant Therapy to Corticosteroids in Acute Endothelial Graft Rejection After Penetrating Keratoplasty: A Randomized Controlled Trial.

PURPOSE: To evaluate the efficacy of topical tacrolimus 0.05% as adjuvant therapy to corticosteroids in the treatment of acute endothelial rejection of a penetrating keratoplasty (PKP) graft. METHODS: Patients with the clinical diagnosis of acute endothelial rejection of a PKP graft were randomized into 2 groups-group 1: receiving topical tacrolimus 0.05% as adjuvant therapy to corticosteroid treatment and group 2: receiving only corticosteroid treatment. Main outcome measures were rejection reversal, time to rejection reversal, and recurrence of rejection. RESULTS: Thirty-one eyes of 31 patients (17 and 14 eyes in group 1 and 2, respectively) were included in the study. The rejection episode completely resolved in 88.2% of patients in group 1 and 85.7% of patients in group 2 [hazard ratio = 0.60, 95% confidence interval (CI) = 0.28-1.29, P = 0.191]. After adjusting for preoperative factors using the inverse-probability weighting method, the time to resolution of rejection was significantly shorter in group 1 than group 2 (average treatment effect = 16, 95% CI, 3.7-28.7, P = 0.013). The recurrence rate of rejection was significantly higher in group 2 (39.7, 95% CI, 12.8-92.6 per 1000 months of follow-up) than in group 1 (3.6, 95% CI, 0.05-19.9 likewise); risk ratio: 11.1, 95% CI, 1.3-95.0, P = 0.028. CONCLUSIONS: Topical tacrolimus 0.05% as an adjunct to steroids can hasten the resolution of endothelial rejection of a PKP graft and potentially decreases the recurrence of rejection. However, it may not improve rejection reversal success.

Refractive lens exchange and piggyback intraocular lens implantation in nanophthalmos: Visual and structural outcomes.

PURPOSE: To evaluate the best piggyback intraocular lens (IOL) implantation method and the outcomes in nanophthalmos eyes and to define the postoperative structural changes. SETTING: Farabi Eye Hospital, Tehran, Iran. DESIGN: Prospective case series. METHODS: Candidates for refractive surgery who were nanophthalmic were recruited. Patients had refractive lens exchange followed by implantation of both IOLs in the bag or 1 IOL in the bag and 1 IOL in the sulcus. The baseline and follow-up visual acuity, refractive status, and structural Scheimpflug imaging were evaluated. Ultrasound biomicroscopy (UBM) was performed 6 months postoperatively. RESULTS: The study comprised 9 nanophthalmic patients (18 eyes) with a mean preoperative uncorrected distance visual acuity (UDVA) of 1.53 logarithm of the minimum angle of resolution (logMAR) ± 0.3 (SD), mean corrected distance visual acuity (CDVA) of 0.34 ± 0.2 logMAR, and mean spherical equivalent (SE) of +13.55 ± 4.0 diopters (D). The mean postoperative UDVA improved from baseline. There was no significant difference in the mean UDVA and CDVA between the 2 IOL groups. Postoperatively, both groups had a significant improvement in SE, a significant rise in anterior chamber depth and angle, and similar UBM measurements. CONCLUSIONS: Piggyback IOL implantation was an effective refractive procedure in nanophthalmic eyes. Both implantation methods resulted in similar outcomes; however, the small number of patients in each group made it less likely that possible differences would be found. The increase in angle values might help prevent the development of closed-angle glaucoma.

Anterior Chamber Depth Change Following Cataract Surgery in Pseudoexfoliation Syndrome; a Preliminary Study.

PURPOSE: To assess the pseudophakic anterior chamber depth (PP-ACD) or effective lens position (ELP) change after cataract surgery in patients with pseudoexfoliation syndrome (PEX). METHODS: Consecutive eyes with PEX and cataract underwent standard phacoemulsification and were implanted with single-piece acrylic posterior chamber intraocular lenses (IOLs). Eyes with severe PEX and with axial length (AL) greater than 24 mm or less than 22 mm were not included. Eyes with capsular complication or unstable bags that needed capsular tension ring insertion were excluded. The SRK-II formula was applied to calculate IOL power for postoperative emmetropia. PP-ACD or ELP was measured using anterior segment optical coherence tomography. Data obtained at one and six months post operation were evaluated during analysis. RESULTS: Twenty-six eyes of 26 subjects (mean age: 72 years; range: 60-84 years) were studied. PP-ACD was deepened (mean change: 0.08 mm) and a concurrent hyperopic shift (0.3 D) was observed postoperatively between month 1 and month 6 (P values ≤0.002). PP-ACD and postoperative refraction changes were correlated with age and AL (P values < 0.025), respectively. Increased hyperopic shift and PP-ACD deepening in eyes with posterior capsule opacification (PCO) was noted postoperatively at six months, but the difference was not statistically significant (P values = 0.15 and 0.2, respectively). CONCLUSION: After cataract surgery in eyes with PEX syndrome, a significant backward movement of the IOL occurs postoperatively in the first six months, which is associated with a concurrent small hyperopic shift.

Preoperative anterior segment optical coherence tomography as a predictor of postoperative phakic intraocular lens position.

PURPOSE: To evaluate anterior segment optical coherence tomography (AS-OCT) in the preoperative simulation of postoperative iris-fixated phakic intraocular lens (pIOL) position in the anterior chamber. SETTING: Farabi Eye Research Center, Department of Ophthalmology, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Case series. METHODS: Using AS-OCT, the pIOL position was simulated preoperatively in 2 ways and compared with the actual postoperative pIOL position. For preoperative evaluations, the simulator was placed on the posterior pigmented epithelium of the iris. Then, the simulation was performed with the simulator placed in the middle of the iris tissue. The following distances were measured: from the center of the pIOL to the endothelium, from the edge of the pIOL to the endothelium, and from the posterior surface of the pIOL to the crystalline lens. RESULTS: The study examined 26 eyes (16 patients). Although all distances in both simulation methods (except the lens vault in the first method of simulation) were highly correlated (all P<.009), only the results with the simulator placed in the middle of the iris tissue were not statistically different from the corresponding postoperative measurements (P=.209 and P=.564 for distance from endothelium to the center and the pIOL edge, respectively). CONCLUSIONS: Using the pIOL template of the AS-OCT system for preoperative simulation of iris-fixated pIOLs improved the criteria for patient selection for implantation of these pIOLs. The simulator should be placed in the middle of the iris tissue for preoperative simulation. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Efficacy of intralesional bevacizumab injection in decreasing pterygium size.

PURPOSE: To evaluate the efficacy of intralesional bevacizumab injection in decreasing size of pterygium. METHODS: Seventeen patients with pterygium (14 with primary and 3 with recurrent pterygium) received intralesional injections of bevacizumab (2.5 mg/0.1 mL). Digital photographs were analyzed by image analysis software to determine the change of corneal involvement as a percentage of the total corneal surface. RESULTS: The mean age of the patients was 45.5 ± 15.8 years. The mean percentage size of lesions before injection was 17.2% ± 4.3% of corneal surface. The mean percentage size of lesions 1 week, 1 month, and 3 months after injection was 15.1% ± 4.3%, 13.4% ± 4.0%, and 14.1% ± 4.4% of corneal surface, respectively. The mean percentage decrease of lesion size was 3.97% ± 3.84%. There were statistically significant differences between percentage of lesion size before and 1 week (P < 0.001), 1 month (P < 0.001), and 3 months (P < 0.001) after injection of bevacizumab. There were neither postinjection ocular complications such as rise of intraocular pressure nor systemic adverse events. Visual acuity did not change after injection of bevacizumab. Despite statistically significant decrease in pterygium size, this decrease does not seem to be clinically significant. CONCLUSIONS: Intralesional bevacizumab injection is fairly effective in reducing the size of pterygium and is well tolerated; however, this effect is not clinically significant.