Evaluation of a uniplanar pupil expansion ring in small-pupil cataract surgery: a feasibility study.

PURPOSE: The aim of this study was to evaluate the effectiveness of a disposable uniplanar pupil expansion device in small-pupil cataract surgery. METHODS: This is a feasibility study carried out at the Rothschild Foundation, Paris, France. Patients undergoing routine cataract surgery with a dilated pupil size < 6 mm, and who agreed to participate in the study were included. The trial enrolled 25 patients, of whom 21 proceeded to cataract surgery using the pupil expansion device to be evaluated. The pupil diameter was measured at defined stages during the cataract surgery, which was performed by a single surgeon, in a single center setting. The 1st generation Bhattacharjee pupil expansion ring was used if the preoperative pupil size was < 6 mm. Intraoperative and postoperative adverse events were recorded. RESULTS: Pupil size immediately after the Bhattacharjee ring implantation was ≥ 6 mm for 15 eyes (71.4%). The mean dilated pupil size before ring insertion was 4.5 ± 0.8 mm (range 2.5-5.8 mm), and the mean pupil size after ring insertion was 6.1 ± 0.3 mm (range 5.9-6.8 mm). Mean pupil size following removal of the ring was 4.2 ± 0.8 mm (range 2.5-5.4 mm). Two adverse events occurred during the surgeries: 1 Bhattacharjee ring broke prior to implantation, and 1 implanted Bhattacharjee ring was unstable and removed before the end of the surgery. No postoperative adverse event was recorded. CONCLUSIONS: The Bhattacharjee ring is an effective pupil expansion device, which facilitates stable pupil expansion during cataract surgery. This study was registered as a clinical trial at clinicaltrials.gov under the number NCT02434588.

Comparison of Laser Platform Estimation and Objective Measurement of Maximum Ablation Depth Using Scheimpflug Pachymetry in Myopic Femtosecond Laser In Situ Keratomileusis.

PURPOSE: To compare the preoperative estimation of maximum ablation depth provided by the laser platform with objective measurement using Scheimpflug pachymetry in myopic femtosecond laser-assisted in situ keratomileusis (FS-LASIK). METHODS: This is a prospective study carried out at the Rothschild Foundation, Paris, France. In 89 consecutive myopic eyes (45 patients) treated with FS-LASIK, the maximum ablation depth was calculated by measuring the difference between preoperative and 3-month postoperative measurements in central corneal thickness using Scheimpflug pachymetry (Pentacam HR; Oculus Optikgeräte, Wetzlar, Germany). These values were compared with the preoperative estimation of the maximum ablation depth provided by the laser platform, without nomogram adjustment. RESULTS: We found a strong linear correlation between laser platform estimation of maximum ablation depth and Scheimpflug pachymetry (P < 0.00001). The mean ablation depth measured using Scheimpflug pachymetry was greater than that predicted by the laser platform, with a mean overall difference of 2.15 µm (P < 0.05). Subgroup analysis revealed a difference in ablation depth measurements of 7.1 µm in the high myopia subgroup, which was the only subgroup where the difference remained statistically significant. CONCLUSIONS: In myopic FS-LASIK, laser platform estimation of maximum ablation depth correlates well with measurement of maximum ablation depth using Scheimpflug pachymetry and therefore can be used safely.

Astigmatic equivalence of 2.2-mm and 1.8-mm superior clear corneal cataract incision.

PURPOSE: To evaluate the astigmatic effects of 2.2-mm and 1.8-mm cataract incisions. METHODS: A randomized prospective study of 190 eyes of 151 patients undergoing superior clear corneal incision (SCCI) was divided into three groups: 61 eyes with a control 3.2-mm SCCI; 66 eyes with a 2.2-mm SCCI; and 63 eyes with a 1.8-mm SCCI. The corneal astigmatism was measured with an autokeratometer preoperatively and 1 month after surgery. The with-the-wound (WTW), against the-wound (ATW), and WTW-ATW changes were calculated using the Holladay-Cravy-Koch formula. RESULTS: The WTW, ATW, and WTW-ATW changes were significantly higher for the control 3.2-mm SCCI than for the 2.2- and 1.8-mm SCCI (all p < 0.001), and no difference was found between the 2.2- and 1.8-mm SCCI incision groups. CONCLUSION: In our study, the astigmatic effects were the same for the 2.2 mm and 1.8 mm incisions and as expected, were significantly lower than the control 3.2 mm incision group.

Assessment of corneal biomechanical properties in normal tension glaucoma and comparison with open-angle glaucoma, ocular hypertension, and normal eyes.

PURPOSE: To assess the biomechanical properties of corneas in patients with normal tension glaucoma (NTG) and to compare them with those of patients with primary open-angle glaucoma (POAG), ocular hypertension (OHT), and normal controls (N). METHODS: Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann intraocular pressure (IOPg), and corneal compensated IOP (IOPcc) were obtained using an ocular response analyzer for 28 eyes in 14 patients with NTG, 75 eyes in 38 patients with chronic POAG, 53 eyes of 27 patients with OHT, and 44 eyes of 22 N controls. IOP using Goldmann applanation tonometry (IOPGA) and ultrasonic central corneal thickness (CCT) were also measured for each eye. Analysis of variance test was used for statistical analysis. RESULTS: CH was significantly lower in the NTG group (9.88±2.02 mm Hg) compared with the N group (11.05±1.53 mm Hg; P<0.01). CRF was significantly lower in the NTG group (9.5±1.89 mm Hg) compared with the POAG group (11.15±2.35 mm Hg; P<0.01) and to the N group (11.00±1.75 mm Hg; P<0.01). CCT was not considered significantly different between the 4 groups. However, IOPcc was found to be significantly lower in NTG group compared with the POAG group and OHT group (P<0.001). CONCLUSION: NTG was associated with significantly lower CRF than chronic POAG and N patients. CH and CRF could be a useful tool in early diagnosis of NTG.

Detection of static cyclotorsion and compensation for dynamic cyclotorsion in laser in situ keratomileusis.

PURPOSE: To evaluate the degree of static and dynamic cyclotorsion using a rotational eye tracker in laser in situ keratomileusis (LASIK) to correct myopic astigmatism. SETTING: Rothschild Foundation, Paris, France. DESIGN: Cohort study. METHODS: Laser in situ keratomileusis with active iris registration using a Zyoptix 100 Hz excimer laser with Advanced Control Eyetracking was performed in eyes with myopic astigmatism. In all cases, iris registration was used to evaluate the degree of static cyclotorsion preoperatively and the degree of dynamic cyclotorsion and intraoperatively. The direction, mean values, and ranges of static and dynamic cyclotorsion were recorded. The amplitude of intraoperative cyclotorsion was reported. RESULTS: The study included 74 consecutive eyes (38 patients). The direction of cyclotorsion was not statistically significant. The mean static cyclotorsion was 3.08 degrees ± 2.68 (SD) (range -7.0 to 14.0 degrees) and the mean dynamic cyclotorsion, 3.39 ± 2.94 degrees (range -10.3 to 13.5 degrees). During photoablation, the mean amplitude of cyclotorsion was 2.69 ± 1.63 degrees (range 0.0 to 9.2 degrees). The magnitude of dynamic cyclotorsion was less than 5 degrees in 66% of eyes, 5 degrees or more in 34% of eyes, and 10 degrees or more in 4% of eyes. CONCLUSIONS: Static and dynamic cyclotorsion was detected with a dynamic eye tracker in eyes having LASIK. Rotational movements were mainly static but had significant amplitude during photoablation.

Correction of high astigmatism: case studies using the mixed-cylinder approach.

PURPOSE: To explain the use of the mixed-cylinder approach in treating moderate to high astigmatism with the NIDEK EC-5000 excimer laser system. METHODS: Retrospective case series report. RESULTS: Three patients with bilateral moderate to high astigmatism were treated successfully using the mixed cylinder approach. CONCLUSIONS: The use of the mixed-cylinder approach with the NIDEK EC-5000 excimer laser may be a safe and predictable option for treating moderate to high astigmatism.

Laser in situ keratomileusis for the correction of residual ametropia after penetrating keratoplasty.

PURPOSE: To evaluate the safety, efficacy, and predictability of excimer laser in situ keratomileusis (LASIK) to correct residual myopia and astigmatism after penetrating keratoplasty (PKP). SETTING: Buzard Eye Institute, Las Vegas, Nevada, USA. METHODS: Twenty-six eyes had LASIK at least 1 year after PKP. All eyes were followed for at least 6 months after LASIK; 22 eyes were followed for 12 months. Sutures were removed at a mean of 13 months post PKP. Laser in situ keratomileusis was performed with the Chiron Automated Corneal Shaper microkeratome (Bausch & Lomb) and the Visx Star excimer laser. Before LASIK, the mean spherical equivalent (SE) was -4.94 diopters (D) +/- 2.79 (SD) and the mean astigmatism was 2.71 +/- 2.33 D; all eyes had regular astigmatism or slightly decentered, irregular astigmatism. RESULTS: At the last follow-up, the mean postoperative uncorrected visual acuity (UCVA) was 20/30, the mean SE was -0.35 +/- 0.65 D, and the mean residual astigmatism was 1.06 +/- 0.67 D. Eighty-six percent of patients had an SE within +/-1.00 D of emmetropia and a UCVA of 20/40 or better. Ten eyes (39%) had 1 or more enhancements, which were performed a mean of 6 months after the primary LASIK. Significant complications such as wound dehiscence, epithelial ingrowth, and corneal decompensation did not occur. At the last follow-up, 18% of patients lost 1 line of best corrected visual acuity and 27% gained 1 line. CONCLUSION: Laser in situ keratomileusis appeared to be a reliable and safe procedure to correct residual myopia and astigmatism after PKP.