Patients Undergoing Phacoemulsification Surgery Research Articles

COMPARISON OF RECENTLY USED PHACOEMULSIFICATION SYSTEMS USING A HEALTH TECHNOLOGY ASSESSMENT METHOD.

To compare the recently used phacoemulsification systems using a health technology assessment (HTA) model. A self-administered questionnaire, which included questions to gauge on the opinions of the recently used phacoemulsification systems, was distributed to the chief cataract surgeons in the departments of ophthalmology of eighteen tertiary hospitals in Shanghai, China. A series of senile cataract patients undergoing phacoemulsification surgery were enrolled in the study. The surgical results and the average costs related to their surgeries were all recorded and compared for the recently used phacoemulsification systems. The four phacoemulsification systems currently used in Shanghai are the Infiniti Vision, Centurion Vision, WhiteStar Signature, and Stellaris Vision Enhancement systems. All of the doctors confirmed that the systems they used would help cataract patients recover vision. A total of 150 cataract patients who underwent phacoemulsification surgery were enrolled in the present study. A significant difference was found among the four groups in cumulative dissipated energy, with the lowest value found in the Centurion group. No serious complications were observed and a positive trend in visual acuity was found in all four groups after cataract surgery. The highest total cost of surgery was associated with procedures conducted using the Centurion Vision system, and significant differences between systems were mainly because of the cost of the consumables used in the different surgeries. This HTA comparison of four recently used phacoemulsification systems found that each of system offers a satisfactory vision recovery outcome, but differs in surgical efficacy and costs.

Evaluation of Opposite Clear Corneal Incision in Controlling Astigmatism in Cataract Patients Undergoing Phacoemulsification Surgery

Aim: To evaluate the role of clear corneal incision combined with opposite clear corneal incision in controlling astigmatism in patients undergoing phacoemulsification surgery for cataract. Design: Prospective clinical study. Methods: 45 consecutive patients planned for phacoemulsification were divided into three equal groups of fifteen patients each: Group 1 presenting without corneal astigmatism, Group 2 having WTR (with-the-rule) and Group 3 having ATR (against-the-rule) astigmatism. All underwent phacoemulsification through 2.8mm clear corneal incision. In Group 1 the temporal clear corneal incision (CCI) was enlarged to 3.2mm before IOL insertion along with 2.2mm superior CCI to neutralise the astigmatism induced by main cataract incision. In Group 2 the superior CCI was enlarged to 3.2mm before IOL insertion, followed by 3.2mm inferior opposite CCI. In Group 3 the temporal CCI was enlarged to 3.2mm before IOL insertion followed by 3.2mm nasal opposite CCI. Results: In Group 1, the overall mean postoperative astigmatism observed was 0.28 ± 0.2D WTR, with 4 out of 15 patients (26.66%) continuing to have nil astigmatism. In Group 2, the mean postoperative astigmatism was reduced from 1.16 ± 0.32D WTR preoperatively, to 0.46 ± 0.28D WTR at 3 months postoperatively. In Group 3, the preoperative astigmatism of -1.25 ± 0.32DATR reduced to -0.38 ± 0.31D ATR, 3 months postoperatively. The reduction in astigmatism was statistically significant in both WTR and ATR astigmatism groups (p < 0.001). Conclusion: More than 50% reduction in astigmatism was achieved in both groups with astigmatism. Thus opposite clear corneal incision (OCCI) is a simple, predictable, safe and effective procedure in reducing mild to moderate preexisting corneal astigmatism in cataract surgery.

Lens capsule-related problems in patients undergoing phacoemulsification surgery

PurposeThis study aimed to compare lens capsule-related problems in mature versus non-mature senile cataracts in patients undergoing phacoemulsification surgery.MethodsA total of 295 patients with senile cataract were divided into two groups according to lens maturation: 105 patients with mature senile cataract comprised Group 1 (study group) and the remaining 190 with non-mature senile cataract comprised Group 2 (control group). Prior to surgery, ophthalmological examination was undertaken. Patients’ best-corrected visual acuity and intraocular pressure were measured and a slit-lamp examination and funduscopy performed. All examination data were recorded and any capsule-related problems during surgery were also recorded. Patient files were reviewed retrospectively and compared between groups. Fisher’s exact test was used in the statistical analysis.ResultsIn Group 1, the capsule-related problems found were: inability to complete capsulorhexis (seven eyes [6.6%]), posterior capsular perforation (three eyes [2.8%]), and conversion to extracapsular surgery (one eye [0.9%]). A posterior capsular perforation was seen in one eye (1%) in the control group. An intraocular lens was inserted into the sulcus in six eyes (5.7%) and one anterior chamber (0.9%) in Group 1 and into the sulcus in one eye (0.5%) of Group 2. The lens was inserted into the capsular bag in all other patients.ConclusionDelaying surgery in patients with cataracts creates a high risk for capsule-related surgical complications. Although capsule dyes make capsulorhexis easier, capsulorhexis is the most problematic phase of phacoemulsification in mature cataracts.

Determinants of Postoperative Corneal Edema and Impact on Goldmann Intraocular Pressure

Recent studies report that increased corneal edema because of contact lens wear under closed lids is associated with elevated Goldmann intraocular pressure (GAT IOP). We sought to assess whether the impact of postoperative corneal edema on GAT IOP would be similar and to determine the differential effect of different amounts of edema. The setting is a tertiary level cataract clinic in Shantou, China. Pre- and postoperative (day 1) GAT IOP, central corneal thickness (CCT), corneal hysteresis, corneal resistance factor, and radius of corneal curvature were measured for consecutive patients undergoing phacoemulsification surgery by 2 experienced surgeons. Corneal edema was calculated as the percentage increase in CCT. Among 136 subjects (mean age, 62.5 ± 15.4 years; 53.7% women), the mean increase in CCT was 10.3% postoperatively. Greater corneal edema was associated with lower GAT IOP in unadjusted analyses (P < 0.03) and in linear regression models (P < 0.01). In the model, higher corneal resistance factor (P < 0.001), lower corneal hysteresis (P < 0.001), and steeper radius of corneal curvature (P < 0.001) were associated with higher GAT IOP. Among subjects with edema < the median, edema was associated with lower GAT IOP (P = 0.004), whereas among those with edema ≥ the median, edema was not associated with GAT IOP. An increase in CCT of 7% was associated with an 8 mm Hg underestimation of GAT IOP in our models. The effect of postoperative edema on GAT IOP seems to be the opposite of contact lens-induced edema. The magnitude of the effect is potentially relevant to patient management.

A possible strategy for implanting blue‐blocking intraocular lenses

Editor, Age-related macular degeneration (AMD) is said to be associated with sunlight exposure. This is supported by some epidemiological studies but not others. Epidemiological studies have also shown AMD progression following cataract surgery (Cuthbertson et al. 2009). Lipofuscin is considered a biomarker for cellular ageing and oxidative damage with one fluorophore A2E found in the retinal pigment epithelium (RPE) with peak sensitivity of short wavelength. It is thought to be an important mediator of AMD progression generating reactive oxygen species on photoexcitation and being phototoxic to RPE cells in culture (Algvere et al. 2006). Short wavelength light is absorbed by the ageing crystalline lens and this protective effect is lost following cataract surgery, likely resulting in cellular damage as a result (Algvere et al. 2006). Experimental studies showing the protective nature of a yellow intraocular lens (IOL) against radiation damage between 400 and 500 nm and the peak blue-light hazard of wavelengths at 435–440 nm (ICNIRP 1997) support this hypothesis (Cuthbertson et al. 2009). However the data is experimental and with conflicting evidence from epidemiological studies, the role of sunlight exposure in AMD remains inconclusive. In the 1980s, patients undergoing phacoemulsification surgery were given protection against radiation of wavelengths below 400 nm with clear UVR-blocking IOLs but not the blue-light hazard. Considering the experimental (Ham et al. 1976) and the epidemiological evidence that blue light induces damage in the retina, it is rational to implant a yellow IOL following phacoemulsification surgery, in patients at risk of AMD. However, early theoretical reports suggest yellow IOLs may have an effect on scotopic vision, reducing visual performance and contrast sensitivity when compared to a clear IOL due to blue light absorption. On the other hand, filtering out blue light improves the contrast on the retina in the sense that Rayleigh scattering in the vitreous is inversely proportional to the forth power of the wavelength. With foveal scotopic vision decreasing with age, the loss of blue light in the image caused by yellow IOLs may have an impact on night activities such as walking down stairs. Theoretical comparison between yellow IOLs and a middle aged crystalline lens indicated that the loss of blue light in the image may cause reduced scotopic sensitivity but this may not be clinically significant for scotopic vision and clinical trials with blue blocking IOLs have demonstrated no impact on contrast sensitivity (Cuthbertson et al. 2009). Blue light is said to have a role in the regulation of circadian rhythms which could affect sleep and lead to depression, although it is unclear how clinically relevant this is. Therefore, using clear IOLs with UV filters is also recommended over yellow IOLs further complicating the choice in IOL selection. Ideally, an IOL should have no effect on scotopic sensitivity and circadian rhythm with maximal protective effective against short wavelength phototoxicity. However, each of these scenarios has different peak wavelengths and therefore IOL selection will be a balance of these functions. Thus, clinical trials were not able to demonstrate a negative impact of blue blocking IOLs (Cuthbertson et al. 2009). However, if concern exists one option is to implant a clear IOL in one eye and a yellow IOL in the fellow eye. In a patient with bilateral asymmetrical AMD, we recommend that consideration should be given to implanting the yellow IOL in the eye with less severe disease to minimize AMD progression. The literature reports that most patients do not notice a problem with colour vision having a clear IOL in one eye and a yellow one in the other (Marshall et al. 2005; Algvere et al. 2006). There is only one case report of a patient who required explantation of the yellow IOL due to colour perception problems (Shah & Miller 2005). We anticipate this strategy will help minimize AMD progression and while preserving scotopic vision for patients undergoing cataract surgery if scotopic vision is an issue.

Safety and efficacy of etanercept therapy in ankylosing spondylitis patients undergoing phacoemulsification surgery

Safety and efficacy of etanercept therapy in ankylosing spondylitis patients undergoing phacoemulsification surgery

Increased anterior chamber penetration of topical levofloxacin 0.5% after pulsed dosing in cataract patients

This study aimed to investigate the rise in aqueous humour (AH) levels of levofloxacin after a specific perioperative pulsed topical drop regimen. Thirty patients undergoing phacoemulsification surgery were administered two preoperative drops of levofloxacin 0.5%, 30 mins apart, and three pulsed drops postoperatively, 5 mins apart. Aqueous humour levels of levofloxacin were measured at the start of surgery and from 5 mins to 90 mins after the last postoperative drop. Samples from individual patients were collected at the time of surgery and at one additional sampling interval by aqueous tap, and analysed using a high-performance liquid chromatography assay. Aqueous humour levels of levofloxacin continued to rise gradually, reaching a mean peak level (C(max)) of 4.4 microg/ml (+/- 2.5) at 60 mins after the last postoperative drop was administered. This level exceeded the minimum inhibitory concentration of common ocular pathogens at least fourfold. At 90 mins after the last drop, mean AH levels remained > 3 microg/ml. This is the first study to measure AH levels of levofloxacin after postoperative pulsed dosing in humans. Higher AH levels were found than in previously reported studies in which only preoperative drops were given and levels were measured at the time of surgery. Levels of levofloxacin continued to rise for 60 mins after administration of the last postoperative drop, demonstrating that delivery and maintenance of effective antibiotic levels may be achievable with alternative dosing schedules.

Antimicrobial Efficacy of Prophylactic Gatifloxacin 0.3% and Moxifloxacin 0.5% in Patients Undergoing Phacoemulsification Surgery

To evaluate the ocular surface and aqueous antimicrobial effects of gatifloxacin and moxifloxacin administered in two dosing regimens to patients undergoing phacoemulsification. Patients were divided between two treatment groups and randomized to receive gatifloxacin 0.3% or moxifloxacin 0.5% within each group. Group 1 patients received antibiotics four times per day for 2 days before surgery with one additional drop the morning of surgery (n=50, each drug). Group 2 patients were treated as in group 1, plus four drops (one drop every 10 minutes) during the hour before surgery (n=60, each drug). Conjunctival and eyelid swabs were taken before surgery, and aqueous humor cultures were obtained immediately after surgery. Pathogens were identified and colony-forming units (CFUs) were counted. No differences were observed between the antibiotics in mean CFUs in conjunctival cultures from group 1 (gatifloxacin, 59.9+/-165.6 CFUs; moxifloxacin, 57.0+/-214.7 CFUs; P=0.939) or group 2 (gatifloxacin, 76.7+/-327.7 CFUs; moxifloxacin, 92.0+/-486.1 CFUs; P=0.830). No differences were observed between antibiotics in mean CFUs in eyelid cultures from group 1 (gatifloxacin, 198.1+/-330.1 CFUs; moxifloxacin, 168.3+/-379.0; P=0.840) or group 2 (gatifloxacin, 556.8+/-1,029.3 CFUs; moxifloxacin, 596.5+/-1,013.5 CFUs; P=0.832). The overall rate of positive aqueous cultures in the 220 patients from groups 1 and 2 combined was less than 1% (i.e., no difference between antibiotics in either group). Preoperative topical ophthalmic gatifloxacin and moxifloxacin produced similar preoperative eyelid and conjunctival bacterial counts and identically low postsurgical aqueous contamination rates.

Dysphotopsia after Cataract Surgery: Comparison of Four Different Intraocular Lenses

Aim: To assess the risk of dysphotopsia after phacoemulsification, with the use of four different intraocular lens (IOL) models. Methods: In this prospective randomized study, 600 patients underwent phacoemulsification surgery. Four study groups were formed, according to the type of the IOL implanted: Meridian HP60M [Bausch & Lomb, hydrogel, 6 mm, three piece (3P), square edge, refraction index (RI): 1.470], Acrysof MA60BM (Alcon, acrylic, 6 mm, 3P, square edge, RI: 1.550), Acrysof MA30BA (Alcon, acrylic, 5.5 mm, 3P, square edge, RI: 1.550) and Clariflex (AMO, silicone, 6 mm, 3P, anterior round and posterior square edge, RI: 1.460). Patients were examined for dysphotopsia symptoms after 1 week, 1, 3 and 6 months. Results: During the first follow-up visit, 117 patients (19.5%) reported dysphotopsia. During the next visits, the actual number of patients still reporting phenomena declined. Optic phenomena occurred less frequently in patients with AMO Clariflex lens, especially when compared to Acrysof (5.5 and 6 mm); IOL odds ratios ranged from 2.27 to 6.7, depending on follow-up time (p value < 0.05). IOL optic diameter was negatively but significantly associated with the risk of dysphotopsia. Conclusions: The design of the optic edge and the optic diameter of the IOL play an important role in the occurrence of dysphotopsia. AMO Clariflex, with round anterior and square posterior edge, overcomes the problem of dysphotopsia to a considerable extent.

Clinical comparison of two topical prednisolone acetate 1% formulations in reducing inflammation after cataract surgery

ABSTRACTPurpose: To compare the efficacy of two formulations of prednisolone acetate 1% in reducing postoperative inflammation in patients having primary phacoemulsification surgery with IOL implantation.Methods: This multicenter study was conducted in randomized, double-masked fashion with a parallel active control group. Patients undergoing phacoemulsification surgery with IOL implantation were assigned to one of two treatment groups receiving study drug in addition to standard therapy. Study drug was administered four times daily beginning one day before surgery, postoperatively for 14 days, then twice daily until the bottle was empty. Clinical efficacy was compared for differences in corneal surface keratitis, anterior chamber cells and flare, and postoperative pain. Results were compared on day 1, 2 weeks, and 4 weeks postoperatively.Results: No statistical differences in clinical efficacy or safety were seen between the two formulations tested at any time point evaluated.Conclusions: In this study of routine cataract patients, both prednisolone acetate 1% formulations are comparably effective and safe when administered for the reduction of inflammation after phacoemulsification surgery with IOL implantation.

Intraocular lens factors that may affect anterior capsule contraction

To examine the various factors comprising intraocular lenses (IOLs) that may affect the degree of anterior capsule contraction after cataract surgery. Randomized controlled clinical trials. Three hundred thirty-one patients scheduled for bilateral cataract surgery were studied to compare the degree of anterior capsule contraction in fellow eyes that received different IOLs with regard to the following factors: (1) optic material-acrylic optic versus silicone optic; (2) optic design-round-edge optic versus sharp-edge optic; (3) haptic material-polymethyl methacrylate (PMMA) loop versus polyvinylidene fluoride loop; and (4) haptic material and design-single-piece acrylic haptic versus 3-piece PMMA haptic. The 2 IOLs implanted in the fellow eyes of each patient had almost the same material and design, except for the specific factor being compared. All patients underwent phacoemulsification surgery with implantation of different IOLs in fellow eyes. The area of the anterior capsule opening was measured using the Scheimpflug videophotography system at 3 days or 1 week (baseline) and at 1, 3, and 6 months after surgery. The percent reduction in the anterior capsule opening area from baseline was determined at 1, 3, and 6 months after surgery. The mean percent reduction of the anterior capsule opening area was significantly greater in eyes with a silicone optic IOL than in eyes with an acrylic optic IOL. However, no significant difference was observed in the percent reduction between round-edge and sharp-edge optic IOLs, between PMMA and polyvinylidene fluoride loop IOLs, and between single-piece acrylic and 3-piece PMMA haptic IOLs. Strong associations were found in the percentage between round-edge and sharp-edge optic IOLs, between PMMA and polyvinylidene fluoride loop IOLs, and between single-piece acrylic and 3-piece PMMA haptic IOLs, whereas there was a relatively weak association between silicone and acrylic optic IOLs. Among the IOL factors examined, optic material affects most significantly the degree of anterior capsule contraction, whereas optic design and haptic material and design are not strongly related to anterior capsule contraction.

Subjective visual experience during phacoemulsification cataract surgery under sub-Tenon's block.

In a prospective survey, 121 patients received sub-Tenon's block and were interviewed on the same day after their phacoemulsification cataract surgery regarding their visual experience in the operated eye during surgery. Majority of patients (81%) reported that they could see some light during surgery and various colours were seen by 56%. Movements of various descriptions were also reported by 40% of patients. The majority of patients (93%) found the visual experience acceptable but 4% thought it to be unpleasant and 3% found it frightening. Patients undergoing phacoemulsification surgery under sub-Tenon's block experience a variety of visual sensations and some patients may be frightened. All patients should receive appropriate preoperative warning.

Efficacy of supplementary intracameral lidocaine in routine phacoemulsification under topical anesthesia

Objective To determine whether the routine use of supplementary intracameral lidocaine has any benefit over topical anesthesia alone when performing phacoemulsification surgery. Design A prospective single-center, randomized, double-masked, clinical trial. Participants A total of 204 patients undergoing phacoemulsification surgery with lens implantation under planned topical anesthesia. Methods Patients were randomly allocated to receive either topical anesthesia plus 0.5 ml intracameral balanced salt solution or topical anesthesia plus 0.5 ml preservative-free 1% intracameral lidocaine. Main outcome measures On the day after surgery, patients were asked to document the discomfort they had experienced using a visual analog scale. Intraoperative discomfort, postoperative discomfort, and discomfort caused by the microscope light were assessed. Results Multiple linear regression analysis did not show any significant relationship between the use of intracameral lidocaine and either intraoperative ( P = 0.34) or postoperative ( P = 0.45) pain scores. There was a small reduction in the discomfort caused by the operating microscope when intracameral lidocaine was used ( P = 0.04). Conclusions In this study, the routine use of intracameral lidocaine as a supplement to topical anesthesia was shown not to have a clinically useful role.