Intraocular pressure rise after small incision cataract surgery: a randomised intraindividual comparison of two dispersive viscoelastic agents

Viscoelastic, Optical, and Surgical Properties of Vitreous Body Replacement Hydrogels After Aging Compared to Porcine Vitreous Bodies And Silicone Oils

Purpose

First- (monomers), second- (pre-gelated), and third- (in situ gelating after injection) generation hydrogels were previously introduced to replace the vitreous body after vitrectomy surgery. In this study, we evaluated the surgical, optical, and viscoelastic properties of vitreous body replacement hydrogels before and after an accelerated aging protocol previously applied to intraocular implants.

Methods

Measurements of injection force, removal speed using a clinically established vitrectomy setup, as well as evaluation of forward light scattering and viscoelastic properties before and after an accelerated aging protocol were conducted. Results were compared to porcine and human vitreous bodies, as well as currently clinically applied lighter- and heavier-than-water silicone oils.

Results

Removal speed of all tested hydrogels is substantially lower than the removal speed of porcine vitreous body (0.2 g/min vs. 2.7 g/min for the best performing hydrogel and porcine vitreous body, respectively). Forward light scattering in second-generation vitreous body replacement hydrogels was higher after the aging process than the straylight of the average 70-year-old vitreous body (9.4 vs. 5.5 deg2/sr, respectively). The viscoelastic properties of all hydrogels did not change in a clinically meaningful manner; however, trends toward greater stiffness and greater elasticity after aging were apparent.

Conclusions

This study demonstrates surgical weaknesses of the hydrogels that need to be addressed before clinical use, especially low removal speed. Pre-linked hydrogels (second-generation) showed inferior performance regarding surgical properties compared to in situ gelating hydrogels (third-generation).

Translational Relevance

This study highlights possible pitfalls regarding surgical and optical properties when applying vitreous replacement hydrogels clinically.

Forward Light Scattering of First to Third Generation Vitreous Body Replacement Hydrogels after Surgical Application Compared to Conventional Silicone Oils and Vitreous Body

To treat certain vitreoretinal diseases, the vitreous body, a hydrogel composed of mostly collagen and hyaluronic acid, must be removed. After vitrectomy surgery, the vitreous cavity is filled with an endotamponade. Previously, pre-clinical hydrogel-based vitreous body substitutes either made from uncrosslinked monomers (1st generation), preformed crosslinked polymers (2nd generation), or in situ gelating polymers (3rd generation) have been developed. Forward light scattering is a measure of Stray light induced by optical media, when increased, causing visual disturbance and glare. During pinhole surgery, the hydrogels are injected into the vitreous cavity through a small 23G-cannula. The aim of this study was to assess if and to what extent forward light scattering is induced by vitreous body replacement hydrogels and if Stray light differs between different generations of vitreous body hydrogel replacements due to the different gelation mechanisms and fragmentation during injection. A modified C-Quant setup was used to objectively determine forward light scattering. In this study, we found that the 1st and 3rd generation vitreous body replacements show very low stray light levels even after injection (2.8 +/- 0.4 deg2/sr and 0.2 +/- 0.2 deg2/sr, respectively) as gel fragmentation and generation of interfaces is circumvented. The 2nd generation preformed hydrogels showed a permanent increase in stray light after injection that will most likely lead to symptoms such as glare when used in patients (11.9 +/- 0.9 deg2/sr). Stray light of the 2nd generation hydrogels was 3- and 2-fold increased compared to juvenile and aged vitreous bodies, respectively. In conclusion, this significant downside in the forward light scattering of the 2nd generation hydrogels should be kept in mind when developing vitreous body replacement strategies, as any source of stray light should be minimized in patients with retinal comorbidities.

Diluting 2.5% Viscoadaptive Sodium Hyaluronate to Prevent Postoperative Intraocular Pressure Rise After Phacoemulsification: A Pilot Study

The most common complication with intraoperative viscoelastic use is an immediate elevation of intraocular pressure, particularly if the viscoelastic agent remains in the eye, which can cause serious effects. Complications may include severe ocular pain, corneal epithelial edema, and increased risk of anterior ischemic optic neuropathy and retinal artery occlusion. This study aims to find an efficient and safe adjunctive method to decrease the incidence of postoperative intraocular pressure rise. When cohesive viscoelastic agents were unavailable due to the pandemic, we diluted Microvisc 2.5% sodium hyaluronate ophthalmic viscosurgical device by 50% prior to intraocular lens implantation. Twelve eyes are included in this study, which are divided into two groups. The study followed a double-blinded methodology in which the physician and the patient were unaware of what group they were in. The first group (seven patients, seven eyes) was treated using the diluted Microvisc 2.5%, and the second group (five patients, five eyes) was controlled with the undiluted Microvisc 2.5%. The primary variable was intraocular pressure, measured at four different timeline points (baseline, day 1, week 1, and month 1). We found that the technique used had easier irrigation and aspiration with minimal viscoelastic agent left in the bag, leading to a lower postoperative intraocular pressure spike. Analysis was conducted using the Wilcoxon signed rank test, and significance was noted between the two groups on postoperative day 1 (p=0.042). The analysis also included the populations' comorbidities (hypertension and diabetes) and postoperative outcomes (pain, corneal edema, and visual acuity).

Incidence and risk factors for postoperative intraocular pressure response to topical prednisolone eye drops in patients undergoing phacoemulsification

AIM/PURPOSE

To report the incidence, risk factors, and magnitude of steroid response in individuals receiving topical 1% prednisolone acetate eye drops following phacoemulsification surgery MATERIALS AND METHODS: Postoperative IOP of 1118 consecutive patients who had uneventful cataract surgery and used 1% topical prednisolone acetate were studied. Baseline ocular parameters like best-corrected visual acuity, IOP, and slit-lamp examination findings were noted preoperatively and at postoperative day 30. Incidence of postoperative intraocular pressure response to steroid was analyzed and graded as mild, moderate, or severe and risk factors studied.

RESULTS

The mean age of our study cohort was 59.49 ± 7.25 years. The overall incidence of steroid response was 3.2%, (2.8% being moderate responders, and 0.4% high responders). Mean preoperative IOP was 14.67 ± 2.2 mm Hg in the study cohort (n = 1118). Mean postoperative IOP was 21.33 ± 7.97 mm Hg in the steroid responder (SR) and 14.66 ± 2.8 mm Hg in the non-responder (NR), with a statistically significant difference from the baseline IOP in the SR group (p < 0.001) and no difference in the NR. Univariate analysis revealed younger age and high axial length as risk factors but on multiple regression analysis, only younger age < 50 years was found to be a significant risk factor for steroid response.

CONCLUSION

The overall steroid response in this population post-cataract surgery was low with most being moderate responders. Younger age and higher axial length were identified as risk factors for steroid response, and hence this warrants the judicious use of steroids in such individuals.

A primer on ocular viscosurgical devices

PURPOSE

To provide pharmacists with an overview of ocular viscosurgical devices (OVDs) and a comprehensive resource describing characteristics of commercially available agents.

SUMMARY

OVDs are substances that are injected into the eye during ophthalmic procedures, such as cataract surgery, to reduce injury to the endothelium that may result from surgical manipulation. Currently available OVDs are composed of one or more of the following active ingredients: sodium hyaluronate, sodium chondroitin sulfate, and hydroxypropylmethylcellulose. Rheologic properties of OVDs, such as viscosity, elasticity, pseudoplasticity, and cohesion, affect the products' function and performance. Based on rheologic properties, OVDs can be generally classified as cohesive or dispersive. Given each products' unique characteristics, OVDs are not interchangeable. An understanding of OVD characteristics and role in practice allows for improved product selection, which varies based on patient characteristics and procedure. Availability of OVD information and literature is generally lacking since OVDs are regulated by the US Food and Drug Administration (FDA) as medical devices. This primer includes an overview of relevant ophthalmic surgical practices and the landscape of comparative efficacy and safety literature to assist in formulary decision-making. This review also provides a comprehensive guide to commercially available OVDs and a discussion on practical considerations for the pharmacist.

CONCLUSION

Pharmacists may be tasked with handling OVDs in institutional settings. Knowledge about OVD rheologic properties, product characteristics, role in practice, and available literature is necessary for managing formularies and ensuring optimal product selection.

Scleral Buckling with Viscoelastics or Gas Injection for Bulging Retinal Detachments: A Retrospective Cohort Study

Objective

To examine the use of a viscoelastic agent instead of air in the vitreous cavity during surgery for scleral buckling.

Methods

This was a retrospective cohort study of patients who underwent scleral buckling surgery for bulging rhegmatogenous retinal detachment (RRD) at Ningbo Eye Hospital from 07/2016 to 12/2019. The patients were grouped into drainage, air injection, cryotherapy and explant (DACE) and drainage, viscoelastic injection, cryotherapy, and explant (DVCE) groups, which were comparatively assessed.

Results

There were 25 and 22 patients in the DVCE and DACE groups, respectively. The surgery was significantly shorter with DVCE than DACE (P < 0.05), with less intraoperative external pressure adjustment (P < 0.05). BCVA was lower in the DVCE group at 1 week compared with the DACE group (P < 0.05). Successful retinal reattachment was observed in 92.0% and 81.8% of the DVCE and DACE groups, respectively (P < 0.05). Cases requiring laser replenishing after the operation were less in the DVCE group compared with the DACE group (P < 0.05). There were no differences in complications and intraocular pressure between the two groups (all P < 0.05).

Conclusion

DVCE has better operative characteristics and faster vision recovery than DACE, with similar outcomes.

Clinical Comparison of the Performance of Two Marketed Ophthalmic Viscoelastic Devices (OVDs): The Bacterially Derived Healon PRO OVD and Animal-Derived Healon OVD

This clinical investigation compared the clinical performance of two marketed ophthalmic viscoelastic devices (OVDs): the bacterially derived Healon PRO OVD (test) and the animal-derived Healon OVD (control) under normal use conditions during cataract removal and lens implantation. This prospective, multicenter, randomized, parallel, participant/evaluator masked, postmarket investigation enrolled 139 subjects (170 eyes), 116 (143 eyes) of which were treated (73 test; 70 control group). Both test and control OVDs were used, at a minimum, to inflate the anterior chamber and protect the endothelium prior to cataract extraction according to the standard procedure. The surgeon completed a postsurgery OVD clinical performance questionnaire, and intraocular pressure (IOP) was measured before surgery and at the 1 day postoperative visit with Goldmann applanation tonometry. Any IOP measurement of 30 mmHg or higher was considered a “spike” and recorded as a study-specific, serious adverse event. The bacterially derived Healon PRO OVD was found to be statistically noninferior to the overall clinical performance of the animal-derived Healon OVD control; thus, the primary hypothesis was satisfied. There were no statistically significant differences between OVD groups for any of the additional endpoints relating to IOP changes or to safety, thus satisfying additional hypotheses. The Healon PRO OVD showed statistically significant improvements in surgeon ratings for ease of injectability, transparency/visibility, and ease of IOL placement. The safety profile was also similar between OVD groups with regards to serious and/or device-related adverse events, as well as medical and lens findings. The results of this clinical investigation support the safety and effectiveness of the bacterially derived, currently marketed Healon PRO OVD and indicate that the intraocular surgical performance was similar between the two OVDs.

Impact of Ophthalmic Viscosurgical Devices in Cataract Surgery

Background

Ophthalmic viscoelastic devices (OVDs) used during small-incision cataract surgery have numerous advantages. However, OVDs have longer retention time in an eye after surgery resulting in intraocular pressure (IOP) spikes. The purpose of this study is to analyze and quantify the effect of various OVDs on both IOP and best corrected visual acuity (BCVA) by systematically reviewing the literature and performing meta-analysis.

Methods

Numerous databases from January 1, 1985, to present were systematically searched. Thirty-six (3893 subjects) of 3313 studies identified were included for analysis. Standardized mean difference (SMD) was computed, and meta-analysis was performed.

Results

A total of 3313 records were retrieved including 1114 from database search and 2199 from grey literature search. Significant increase in postoperative IOP in 1-day follow-up with Healon (SMD = 0.37, CI: [0.07, 0.67]), Viscoat (SMD = 0.29, CI: [0.13, 0.45]), Provisc (SMD = 0.46, CI: [0.17, 0.76]), and Soft Shell (SMD = 0.58, CI: [0.30, 0.86]) was computed. On the other hand, results implied a nonsignificant increase in postoperative IOP with Healon GV (SMD = 0.07, CI: [−0.28, 0.41]), Healon5 (SMD = 0.15, CI: [−0.33, 0.64]), 2% HPMC (SMD = 0.32, CI: [−0.0, 0.64]), and OcuCoat (SMD = 0.26, CI: [−0.37, 0.9]). Additionally, a nonsignificant reduction in postoperative IOP was inferred with Viscoat + Provisc (SMD = −0.28, CI: [−2.23, 1.68]).

Conclusion

Improvement in IOP was shown with Viscoat + Provisc. Additionally, IOP nonsignificant upsurge was observed with Healon GV, Healon5, 2% HPMC, and OcuCoat compared to significant upsurge with Healon, Viscoat, and Soft Shell.

Review of anaesthetic management for cataract surgery in transplant recipients

The prevalence of transplantation is on the increase worldwide. Corneal transplantation is the most common form of human donor transplantation. Transplantation of other organs and bone marrow is established treatment for various end-organ failure and many haematological conditions, respectively. Success and survival of these patients have increased with advances in immunosuppression. Unfortunately, these patients are susceptible to cataract formation as a consequence of immunosuppressive therapy and accelerated progression of several diseases. Topical anaesthesia and regional ophthalmic blocks are ideal for cataract surgery in cooperative adults. General anaesthesia may be required in children, for extremely anxious or claustrophobic adults and for complex surgery such as simultaneous cataract and corneal transplantation. The perioperative anaesthetic management of cataract surgery in a transplant recipient is no different to a standard technique in a healthy adult, but additional challenges are posed by the underlying pathology necessitating transplantation, function of the transplanted organ, physiological and pharmacological problems of allograft denervation, side-effects of immunosuppression, risk of infection and potential for rejection. This narrative review summarises optimal anaesthetic management in transplant recipients undergoing cataract surgery.

Safety of the Minimum Ophthalmic Viscosurgical Device Technique in Phakic Implantable Collamer Lens Implantation

PURPOSE

To compare the safety of the minimum ophthalmic viscosurgical device (OVD) technique with the standard procedure in phakic Visian Implantable Collamer Lens (ICL) (STAAR Surgical AG, Nidau, Switzerland) implantation.

METHODS

This retrospective cohort study evaluated a total of 147 eyes of 74 patients who underwent ICL implantation with the minimum OVD technique (minimum OVD group) and 154 eyes of 77 patients with the standard procedure (standard OVD group). Intraoperative and postoperative complications were recorded. Preoperative and postoperative visual acuity, intraocular pressure (IOP), aqueous depth (AQD), and central corneal endothelial cell density (ECD) were collected and analyzed over the 12-month follow-up. Lens vault and occurrence of paracentesis after surgery were also recorded.

RESULTS

No intraocular complications were observed. No difference was found in visual outcomes, lens vault, and AQD at all time points between the two groups (P > .05). The minimum OVD group had significantly lower IOP than the standard OVD group at 2 hours (17.04 ± 4.21 vs 19.40 ± 6.78 mm Hg, P < .001) and 3 hours (15.12 ± 3.38 vs 17.15 ± 5.09 mm Hg, P < .001) postoperatively. The IOP gradually returned to the preoperative level after 24 hours postoperatively. The occurrence rate of paracentesis was significantly less in the minimum OVD group compared with the standard group (0.68% [1 of 147] vs 3.2% [5 of 154], P < .001). ECD was not significantly different between groups at all time points (P > .05).

CONCLUSIONS

The minimum OVD technique could achieve visual and structural outcomes comparable to the standard procedure without additional damage to the corneal endothelial cells, while reducing the IOP fluctuations after surgery. [J Refract Surg. 2020;36(1):42-48.].

Transzonular capsulo-hyaloidal hydroseparation with optional triamcinolone enhancement: A technique to detect or induce anterior hyaloid membrane detachment for primary posterior laser capsulotomy

Primary posterior laser capsulotomy (PPLC) requires adequate visualization and spacing of the posterior lens capsule (PLC) and anterior hyaloid membrane (AHM). After intraocular lens implantation and watertight incision hydration, the laser is redocked for optical coherence tomography reimaging. If the PLC and AHM are not imaged or interspaced adequately, transzonular capsulo-hyaloidal hydroseparation is attempted by rinsing the zonular fibers with fluid. If the PLC or AHM are still not detected or discernable, an attempt follows to mark the Berger space using diluted triamcinolone acetate. Before hydroseparation, the AHM or PLC are often invisible or variably attached. If structures cannot be defined, triamcinolone-added hydroseparation is often effective in defining the AHM and Berger space. Transzonular capsulo-hyaloidal hydroseparation with an optional triamcinolone acetate addition can initiate or complete AHM detachment and improve visibility and patency of Berger space for augmenting control and feasibility of PPLC.

Changes in Corneal Biomechanics and Intraocular Pressure Following Cataract Surgery

PURPOSE

To investigate the effects of cataract surgery on corneal biomechanics and intraocular pressure (IOP) measured with the updated Corvis ST tonometer (CST).

DESIGN

Prospective, interventional case series study.

METHODS

This study included 39 eyes of 39 cataract patients. CST measurements were performed at presurgery (Pre) as well as 1 week (1W), 1 month (1M), and 3 months (3M) postsurgery. The following CST parameters were recorded: deformation amplitude max (DA max), DA ratio max 1 mm and 2 mm, integrated radius, stiffness parameter at applanation 1 (SP A1), Ambrosio relational thickness to the horizontal profile (ARTh), Corvis biomechanical index (CBI), central corneal thickness (CCT), noncorrected intraocular pressure (IOPnct), and biomechanically corrected IOP (bIOP). IOP was also measured with Goldmann applanation tonometry and the noncontact tonometer CT-90A. All measurements were compared at each period using the linear mixed model, with and without adjustment for bIOP and CCT.

RESULTS

All IOP measurements decreased over time (P < .01). CCT was increased at 1W and 3M (P < .01), whereas ARTh was decreased at 1W and 1M (P < .01), but returned to its Pre level at 3M. DA max and Integrated radius were increased at 3M (P < .01), whereas SP A1 was decreased at 3M (P < .01). CBI was increased at 1W (P < .01), but returned to its Pre level at 1M.

CONCLUSIONS

IOP and Corneal biomechanical properties are changed after cataract surgery. In particular, SP A1 decreases while DA max and integrated radius increase, even at 3M, suggesting a less stiff cornea.

Cataract surgery outcome in patients with non-glaucomatous pseudoexfoliation

Aim. To study the outcome of cataract surgery in eyes with pseudoexfoliation without signs of glaucoma. Methods. This prospective study was done over nine months on patients with pseudoexfoliation undergoing small incision cataract surgery. Only patients with normal intraocular pressure (Central Corneal Thickness Corrected), normal cup disc ratio and open angles were included. Patients on anti-glaucoma medication were excluded. Patients underwent surgery performed by a single senior surgeon. Intraoperative and postoperative day (POD) 1 findings were noted. Results. The mean age of the patients was 61.60 years +/ - 10.21 years. Males were 46% (n=16). Right eye was operated upon in 60% of the cases (n=21). The mean pupil dilation was 5.1 mm +/ - 1.47 mm. The postoperative day 1 visual acuity of the patients was logMar 1.02 +/- 0.64 and the mean POD 1 intraocular pressure was noted to be 26.23 mmHg +/ - 11.40 mmHg. Five cases had a zonular dialysis intraoperatively due to weak zonules. 11 cases had high anterior chamber reaction of 2+ or more. Four cases had unavoidable sphincter tears and two cases had iridodialysis superiorly during nucleus delivery. Conclusions. Intraoperative complications should be anticipated in patients with pseudoexfoliation even without glaucomatous changes due to poor pupillary dilation and zonular weakness. First postoperative day visual acuity in pseudoexfoliation patients undergoing cataract surgery was found to be low due to severe anterior chamber inflammation causing elevated intraocular pressure and corneal edema. Abbreviations. POD = Postoperative day, PEX = Pseudoexfoliation syndrome, LOXL 1 = Lysyl oxidase-like 1, IOP = Intraocular pressure, AC = Anterior chamber, IOL = Intraocular lens.

Outflow enhancement by three different ab interno trabeculectomy procedures in a porcine anterior segment model

PURPOSE

To evaluate three different microincisional ab interno trabeculectomy procedures in a porcine eye perfusion model.

METHODS

In perfused porcine anterior segments, 90° of trabecular meshwork (TM) was ablated using the Trabectome (T; n = 8), Goniotome (G; n = 8), or Kahook device (K; n = 8). After 24 h, additional 90° of TM was removed. Intraocular pressure (IOP) and outflow facility were measured at 5 and 10 μl/min perfusion to simulate an elevated IOP. Structure and function were assessed with canalograms and histology.

RESULTS

At 5 μl/min infusion rate, T resulted in a greater IOP reduction than G or K from baseline (76.12% decrease versus 48.19% and 47.96%, P = 0.013). IOP reduction between G and K was similar (P = 0.420). Removing another 90° of TM caused an additional IOP reduction only in T and G but not in K. Similarly, T resulted in the largest increase in outflow facility at 5 μl/min compared with G and K (first ablation, 3.41 times increase versus 1.95 and 1.87; second ablation, 4.60 versus 2.50 and 1.74) with similar results at 10 μl/min (first ablation, 3.28 versus 2.29 and 1.90 (P = 0.001); second ablation, 4.10 versus 3.01 and 2.01 (P = 0.001)). Canalograms indicated circumferential flow beyond the ablation endpoints.

CONCLUSIONS

T, G, and K significantly increased the outflow facility. In this model, T had a larger effect than G and K.

Comparison of the Effect of Sodium Hyaluronate (Ophthalin®) and Hydroxypropylmethylcellulose (HPMC-Ophtal®) on Corneal Endothelium, Central Corneal Thickness, and Intraocular Pressure after Phacoemulsification

PURPOSE

To prospectively evaluate the effects of 2% hydroxypropyl-methylcellulose (HPMC-Ophtal) and sodium hyaluronate 1% (Ophthalin) on intraocular pressure, corneal thickness, and endothelial cell loss in small incision cataract surgery with implant.

METHODS

A total of 110 patients undergoing routine phacoemulsification with implant received either 2% hydroxypropyl methylcellulose or sodium hyaluronate 1% as ophthalmic viscosurgical device. Pre- and postoperative slitlamp examination, intraocular pressure measurement (preoperatively and at 1-4 hours, 1 day, and 7 days postoperatively), ultrasonic pachymetry (preoperatively and at 1 week, 4-6 weeks, and 12 weeks post operatively), and corneal endothelial cell count (preoperatively and 12 weeks postoperatively) were performed. Data were analyzed using two-way analysis of variance.

RESULTS

All measurements were comparable between the two groups preoperatively. Intraocular pressure was significantly lower in the Ophthalin group at 1 day post operatively, while no significant difference was found between the two groups on the 1-4 hours and 7 days examination. The central corneal thickness was not significantly different between the two groups at any postoperative visit . However, the mean cell density demonstrated a significant fall of 11.76% for Ophthalin and 4.27% for HPMC-Ophtal at 12 weeks post-operatively, the difference between the two being significant (p=0.009).

CONCLUSIONS

2% Hydroxypropyl methylcellulose, compared with sodium hyaluronate 1%, is superior in protecting the corneal endothelial cells, has the same effect on central corneal thickness, and is associated with slightly higher intraocular pressure 1 day post operatively. It compares favorably with sodium hyaluronate 1% and can be used as an effective and cheaper alternative in routine small incision cataract surgery with implant.

Acute pulmonary oedema due to single dose acetazolamide taken after cataract surgery

An increase in intraocular pressure following cataract surgery is very common. The main reason for this condition is viscoelastic agent remaining in the eye, which leads to mechanical obstruction of the trabecular meshwork. Prophylaxis with oral acetazolamide is frequently practised to prevent this early rise in intraocular pressure in the preoperative and postoperative periods. We report a case of an 81-year-old man with acute pulmonary oedema due to prophylactic acetazolamide intake after cataract surgery. The case is presented in order to draw attention to this serious complication.

Femtosecond laser-assisted cataract surgery without OVD: a prospective intraindividual comparison

PURPOSE

To compare femtosecond laser-assisted cataract surgery without the use of ophthalmic viscosurgical device (OVD) with standard phacoemulsification using OVD.

METHODS

This was a prospective, randomized, single-center trial of 37 patients (74 eyes) diagnosed as having significant cataract in both eyes. Randomly, one eye underwent standard phacoemulsification with OVD (the OVD group); this group acted as controls. The other eye was treated with the femtosecond laser; the subsequent manual part of the procedure was performed without OVD (non-OVD group). Time of surgery, amount of fluid used during phacoemulsification, central corneal thickness, intraocular pressure, endothelial cell count, and visual acuity were documented over the 6-month follow-up.

RESULTS

There were no major complications and no significant difference in overall surgery time (non-OVD: 375 ± 81 seconds; OVD: 362 ± 43 seconds; P = .713) and in the quantity of fluid passing through the eye (non-OVD: 187 ± 35 mL; OVD: 186 ± 27 mL; P = .952) between groups. Endothelial cell loss after 6 months was not significantly different between groups (non-OVD: -2.4%; OVD: -2.7%; P = .880). Central corneal thickness was not different at 1 week postoperatively between groups (non-OVD: 575 ± 45 µm; OVD: 573 ± 46 µm; P = .820). Three patients in the OVD group and one patient in the non-OVD group experienced intraocular pressure greater than 25 mm Hg at 1 day postoperatively. There were no significant differences in corrected distance visual acuity between groups (logMAR non-OVD: 0.024; OVD: 0.038; P = .461).

CONCLUSIONS

Femtosecond laser-assisted treatment allows the cataract surgeon to perform phacoemulsification and intraocular lens implantation without the use of OVD at no additional risk to the corneal endothelium. Furthermore, there was a tendency toward fewer increases in intraocular pressure in patients treated with the femtosecond laser.

Safety of hydroimplantation: a foldable intraocular lens implantation without the use of an ophthalmic viscosurgical device

PURPOSE

To compare the safety of a single-piece, foldable intraocular lens (IOL) hydroimplantation with that of a standard implantation using an ophthalmic viscosurgical device (OVD).

METHODS

One hundred consecutive patients with bilateral age-related cataract surgery were enrolled into a prospective double-blind study. Each patient's first eye was randomly assigned to a standard implantation technique with an OVD or the hydroimplantation technique, while the fellow eye received the opposite technique. The main outcomes measured were endothelial cell loss, postoperative changes of intraocular pressure (IOP), and the frequency of complications.

RESULTS

The reduction of endothelial cell density 1 month and 6 months after the surgery was 9.76% ± 13.5%, 10.7% ± 12.6%, respectively, in group A (OVD) and 9.07% ± 12.7%, 9.13% ± 13.7%, respectively, in group B (hydroimplantation). The differences were not statistically significant. The mean IOP 2 hours after surgery was 10.19 ± 6.78 mm Hg in group A and 9.92 ± 7.01 mm Hg in group B. Twenty-four hours and 1 month after surgery, the mean IOP was 14.52 ± 5.59 mm Hg and 13.21 ± 3.5 mm Hg, respectively, in group A, and 15.45 ± 5.77 mm Hg and 13.1 ± 3.44 mm Hg, respectively, in group B. The differences between groups A and B were not statistically significant.

CONCLUSIONS

The hydroimplantation technique is a safe technique for single-piece foldable IOL implantation. There was no increase in intraoperative and postoperative complications compared with the standard implantation technique using an OVD.

Timolol 0.1% Gel versus Timolol 0.5% Eyedrops in the Prophylaxis of Ocular Hypertension after Phacoemulsification Surgery

Purpose

To determine the efficacy of timolol 0.1% gel in preventing increased intraocular pressure (IOP) after uncomplicated cataract surgery.

Methods

In this prospective, double-blinded, randomized study were enrolled 70 patients who underwent uncomplicated cataract surgery with phacoemulsification and intraocular lens implantation. After cataract surgery, 25 patients received a single instillation of timolol 0.1% gel (group A); 20 a single instillation of timolol 0.5% eyedrops (group B); and 25 no treatment (group C). The IOP was measured before surgery (T0) and 5 minutes (T1), 2 hours ± 30 minutes (T2), 4 hours ± 30 minutes (T3), and 24 hours ± 180 minutes after surgery (T4).

Results

The patients in groups A and B had lower mean IOP values than those in group C at T2, T3, and T4; IOP was higher at T2 and T3 than at T1 in the control group. The IOP spikes in group C were higher than those observed in groups A and B: at T2, they were observed in 40% of the patients in group A, 30% in group B, and 76% in group C; and at T3, in respectively 20%, 10%, and 68%; and at T4, in respectively 4%, 0%, and 28%.

Conclusions

Timolol 0.1% gel is as effective as timolol 0.5% eyedrops in reducing IOP and in limiting the occurrence of IOP spikes for up to 24 hours after phacoemulsification.

Effects of phacoemulsification surgery on ocular hemodynamics

AIM

To evaluate the possible effects of phacoemulsification cataract surgery on ocular hemodynamics.

METHODS

In this prospective study, intraocular pressure (IOP), pulsatile ocular blood flow (POBF), and ocular pulse amplitude (OPA) were measured pre-operatively (baseline) and at 1 week and 3 weeks postoperation in 52 eyes of 26 patients (mean age 63.15±10.25 years) scheduled for unilateral phacoemulsification cataract surgery with intraocular lens implantation. In all of the eyes, a blood flow analyzer (Paradigm DICON; Paradigm Medical Industries Inc.; USA) was used to obtain measurements of IOP, POBF, and OPA. The data obtained from operated eyes were compared statistically to untreated fellow phakic eyes of the patients.

RESULTS

For operated eyes, the mean baseline IOP, POBF, and OPA values were 15.9±4.64mmHg, 17.41±4.84µL/s, and 2.91±1.12mmHg, respectively. The IOP, POBF, and OPA values were 17.19±4.34mmHg, 17.56±6.46µL/s, and 3.12±1.1mmHg, respectively, in the nonoperated control eyes. Statistically significant differences from baseline measurements were not observed 1 week and 3 weeks postoperation for the operated or nonoperated eyes. There were also no statistically significant differences in any measurements between the operated and nonoperated eyes in all the examination periods (P>0.05 for all).

CONCLUSION

Uncomplicated phacoemulsification surgery does not affect ocular hemodynamics in normotensive eyes with cataracts.

IOP Maintenance in SLT-treated Eyes following Subsequent Phacoemulsification and IOL

To assess whether the intraocular pressure (IOP) in selective laser trabeculoplasty (SLT)-treated eyes is maintained following subsequent phacoemulsification and lens implant (phaco + IOL).

Retrospective single center review of 45 eyes of 35 patients who had open angle glaucoma (OAG), successfully treated by SLT by the same surgeon (EA), and then had routine phaco + IOL by same surgeon (EA).

The main outcome measures were baseline (SLT-treated) IOP and IOP at 3, 6 and 12 months following subsequent routine phaco + Intraocular lens (IOL). Secondary outcome measures were visual acuity pre- and post (phaco + IOL) and any complications.

The study found that IOP reduction with SLT is not significantly affected by subsequent phaco + IOL in patients with OAG.

How to cite this article: Ansari E. IOP Maintenance in SLT-treated Eyes following Subsequent Phacoemulsification and IOL. J Current Glau Prac 2013;7(1):17-18.

A clinical comparison between DisCoVisc and 2% hydroxypropylmethylcellulose in phacoemulsification: a fellow eye study

OBJECTIVE

This study sought to compare the effects and outcomes of two ophthalmic viscosurgical devices, 1.6% hyaluronic acid/4.0% chondroitin sulfate and 2.0% hydroxypropylmethylcellulose, during phacoemulsification.

METHODS

This prospective, randomized clinical trial comprised 78 eyes (39 patients) that received phacoemulsification performed by the same surgeon using a standardized technique. Patients were randomly assigned to receive either 1.6% hyaluronic acid/4.0% chondroitin sulfate or 2.0% hydroxypropylmethylcellulose on the first eye. The other eye was treated later and received the other viscoelastic agent. Preoperative and postoperative examinations (5, 24 and 48 hours; 7 and 14 days; 3 and 6 months) included measurements of the total volume of the ophthalmic viscosurgical device, ultrasound and washout times to completely remove the ophthalmic viscosurgical device, intraocular pressure, central corneal thickness and best-corrected visual acuity. The corneal endothelial cell count was measured at baseline and at six months postoperatively. ClinicalTrials.gov: NCT01387620.

RESULTS

There were no statistically significant differences between groups in terms of cataract density or ultrasound time. However, it took longer to remove 2.0% hydroxypropylmethylcellulose than 1.6% hyaluronic acid/ 4.0% chondroitin sulfate, and the amount of viscoelastic material used was greater in the 2.0% hydroxypropylmethylcellulose group. In addition, the best-corrected visual acuity was significantly better in the hyaluronic acid/ chondroitin sulfate group, but this preferable outcome was only observed at 24 hours after the operation. There were no statistically significant differences between the two ophthalmic viscosurgical devices regarding the central corneal thickness or intraocular pressure measurements at any point in time. The corneal endothelial cell count was significantly higher in the hyaluronic acid/chondroitin sulfate group.

CONCLUSION

The ophthalmic viscosurgical device consisting of 1.6% hyaluronic acid/4.0% chondroitin sulfate was more efficient during phacoemulsification and was easier to remove after IOL implantation than 2.0% hydroxypropylmethylcellulose. In addition, the corneal endothelial cell count was significantly higher following the use of hyaluronic acid/chondroitin sulfate than with hydroxypropylmethylcellulose, which promoted an improved level of corneal endothelium protection.

Short-term changes in intraocular pressure after phacoemulsification in glaucoma patients

PURPOSE

To evaluate short-term intraocular pressure (IOP) changes after phacoemulsification in glaucoma and normal patients and the effect of oral acetazolamide (Diamox) to control IOP in these patients.

METHODS

120 patients undergoing cataract surgery were included in this prospective multicenter study involving 6 University Eye Clinics: 60 patients with well-controlled primary open-angle glaucoma (POAG) and 60 controls. Half of the study participants received oral acetazolamide, 250 mg, 1 and 6 h after surgery. The treated and untreated groups were matched for age and density of cataract. All patients underwent a standard phacoemulsification procedure and were checked for IOP with Goldmann tonometry in the morning before surgery and then at 3, 6, 21 and 24 h postoperatively by a masked evaluator.

RESULTS

The group with POAG showed a significant postsurgical increase in IOP (p < 0.001) at all time points. Six of thirty (20%) untreated POAG patients showed at least 1 IOP reading above 30 mm Hg whereas acetazolamide significantly reduced postoperative IOP at all time points (p < 0.01) and in no case was IOP >30 mm Hg. The control group had high IOP during the first 6 h (p < 0.01), but normal values thereafter.

CONCLUSION

A significant short-term IOP increase may be found after phacoemulsification both in POAG and normal patients; this is not dangerous in normal subjects, but can be potentially dangerous in POAG patients. The use of systemic acetazolamide provided significant control of IOP and could be considered a 'possible standard' management of cataract surgery in POAG patients.

Safety, efficacy, and intraoperative characteristics of DisCoVisc and Healon ophthalmic viscosurgical devices for cataract surgery

Purpose

To evaluate the safety and efficacy of DisCoVisc ophthalmic viscosurgical device (OVD, Alcon Laboratories, Inc) with respect to a comparator, Healon OVD (Advanced Medical Optics, Inc).

Patients and methods

In this prospective study, patients with cataracts were randomized to an OVD, and then received phacoemulsification and injection of an intraocular lens. After each surgery, unmasked investigators completed subjective questionnaires about OVD characteristics during each stage of the procedure. Masked technicians evaluated objective safety parameters of intraocular pressure (IOP) and endothelial cell density, with 90 days of follow-up.

Results

The DisCoVisc OVD group (128 eyes) and the Healon OVD group (121 eyes) had statistically similar outcomes for IOP and for endothelial cell loss. Subjectively assessed viscosity was statistically different (P < 0.0001), with Healon OVD most often rated “cohesive” and DisCoVisc OVD most often rated “both dispersive and cohesive”. Workspace maintenance differed between groups (P < 0.0001), with workspace most frequently rated “full chamber maintained” when using DisCoVisc OVD and most frequently rated “workspace maintained” when using Healon OVD. “Flat” or “shallow” workspace ratings occurred only in the Healon OVD group.

Conclusion

DisCoVisc OVD had both cohesive and dispersive properties, and was safe and effective for every stage of cataract surgery.

Viscoless microincision cataract surgery

A cataract surgery technique is described in which incisions, continuous circular capsulorhexis and hydrodissection are made without the use of any viscoelastics. Two small incisions are created through which the different parts of the procedure can take place, maintaining a stable anterior chamber under continuous irrigation. Subsequent bimanual phacoemulsification can be done through these microincisions. At the end of the procedure, an intraocular lens can be inserted through the self-sealing incision under continuous irrigation. 50 consecutive cataract patients were operated on without the use of viscoelastics and then compared with a group of 50 patients who had been helped with viscoelastics. No difference in outcome, endothelial cell count or pachymetry was noted between the two groups. No intraoperative complication was encountered. Viscoless cataract surgery was a safe procedure with potential advantages.

Complications of cataract surgery

Modern cataract surgery is safe in more than 95 per cent of patients. In the small number of cases where a serious complication occurs, the most common is an intra-operative posterior capsular rupture. This can lead to vitreous loss or a dropped nucleus and can increase the risk of post-operative cystoid macular oedema or retinal detachment. Post-operatively, posterior capsular opacification is the most common complication and can be readily treated with a YAG capsulotomy. The most devastating complication is endophthalmitis, the rate of which is now significantly decreased through the use of intracameral antibiotics. As a clinician, the most important step is to assess the patient pre-operatively to predict higher risk individuals and to counsel them appropriately. In these patients, various pre- or intra-operative management steps can be taken in addition to routine phacoemulsification to optimise their visual outcome.

Effects of some ophthalmic medications on pupil size: a literature review

Ophthalmological pharmacology is a rapidly expanding field aimed at achieving the safest and most effective treatment results. Physicians must be aware of the side-effect profiles, both beneficial and harmful, of medications currently used. This review highlights the available data on the effect of some ophthalmic medications on pupil size; it was limited to all reports or studies describing topical ophthalmic agents not originally designed or indicated to alter pupil diameter. This awareness will protect patients from unwanted drug-induced side effects and will improve clinical management and patient care.

Comparison of the effect of Viscoat and DuoVisc on postoperative intraocular pressure after small-incision cataract surgery

PURPOSE

To evaluate the effect of Viscoat (sodium chondroitin sulfate 4%-sodium hyaluronate 3%) and DuoVisc (Viscoat and Provisc [sodium hyaluronate 1%]) on postoperative intraocular pressure (IOP) after bilateral small-incision cataract surgery.

SETTING

Department of Ophthalmology, University of Vienna, Vienna, Austria.

METHODS

This prospective randomized study comprised 60 eyes of 30 consecutive patients with age-related cataract in both eyes. Each patient's eyes were randomly assigned to receive Viscoat or DuoVisc during cataract surgery. DuoVisc is a packet containing 2 ophthalmic viscosurgical devices (OVDs): the dispersive Viscoat, which was used for intraocular lens (IOL) implantation. In the Viscoat group, the Viscoat was used during the entire surgery. The intraocular pressure (IOP) was measured preoperatively as well as 1, 6, and 20 to 24 hours postoperatively.

RESULTS

One and 6 hours postoperatively, the mean IOP was significantly higher in the Viscoat group than in the DuoVisc group (25.8 mm Hg and 20.5 mm Hg, respectively, at 1 hour and 24.7 mm Hg and 21.1 mm Hg, respectively, at 6 hours) (P<.05). At 20 to 24 hours, the mean IOP was not statistically significantly different between the 2 groups. Intraocular pressure spikes to 30 mm Hg or higher occurred in 4 eyes in the DuoVisc group and 11 eyes in the Viscoat group (P<.05).

CONCLUSIONS

Viscoat caused significantly higher IOP increases and significantly more IOP spikes than DuoVisc in the early postoperative period. Therefore, if Viscoat is used during cataract surgery, an additional cohesive OVD should be used for IOL implantation.

Soft-shell technique using Viscoat and Healon 5: a prospective, randomized comparison between a dispersive-viscoadaptive and a dispersive-cohesive soft-shell technique

PURPOSE

To compare the efficacy of the dispersive-viscoadaptive soft-shell technique using Viscoat and Healon 5 to the dispersive-cohesive soft-shell technique in reducing corneal endothelial cell damage during cataract surgery.

METHODS

In this prospective randomized study, 207 eyes of 171 cataract patients underwent phacoemulsification using the dispersive-viscoadaptive soft-shell technique (V-group, 102 eyes) with Viscoat and Healon5 or the dispersive-cohesive soft-shell technique (C-group, 105 eyes) with Viscoat and a cohesive agent (Opegan-Hi). Each group was divided into two subgroups depending on the amount of ultrasound (%Min) used during phacoemulsification. Corneal endothelial cell density was examined preoperatively and 3 months postoperatively. The endothelial cell loss was compared between the two groups, and also between the subgroups.

RESULTS

The mean endothelial cell loss 3 months after surgery was 8.4 +/- 5.6% standard deviation (SD) in the V-group and 8.2 +/- 6.2% in the C-group (P = 0.787). In the subgroups with ultrasound of 10 %Min or less, the mean endothelial cell loss 3 months after surgery was 6.6 +/- 4.6% in the V-group and 5.5 +/- 5.0% in the C-group (P = 0.104). In the subgroups with ultrasound of over 10 %Min, this value was 10.6 +/- 6.3% in the V-group and 11.9 +/- 5.7% in the C-group (P = 0.413). The correlation coefficient of the endothelial cell loss rate and %Min was 0.245 (P = 0.0129) in the V-group and 0.501 (P < 0.0001) in the C-group.

CONCLUSION

The dispersive-viscoadaptive soft-shell technique is as effective as the dispersive-cohesive soft-shell technique in protecting corneal endothelial cells during phacoemulsification regardless of the amount of ultrasound energy used.

Intraocular Pressure Elevation within the First 24 Hours after Cataract Surgery in Patients with Glaucoma or Exfoliation Syndrome

OBJECTIVE

To investigate whether eyes with glaucoma or exfoliation syndrome without glaucoma are prone to exhibit intraocular pressure (IOP) elevation shortly after cataract surgery and, if so, whether timolol maleate 0.5% reduces these spikes.

DESIGN

Prospective randomized double-masked clinical trial.

PARTICIPANTS

One hundred twenty-two patients with normal eyes, medically well-controlled glaucoma, or exfoliation syndrome who underwent uneventful phacoemulsification cataract extraction.

METHODS

Patients were randomly assigned to an immediately postoperative drop of either timolol maleate 0.5% or no treatment. Intraocular pressure was measured preoperatively and 4, 8, and 24 hours and 1 week later.

MAIN OUTCOME MEASURES

Intraocular pressure measurements.

RESULTS

The changes in postoperative IOP over time differed significantly between glaucoma, exfoliation syndrome, and normal (P = 0.005). Intraocular pressure was significantly lower in the normal group (n = 25) than in both the glaucoma (n = 18) and exfoliation syndrome (n = 19) groups (P<0.001). With 1 drop of prophylactic timolol maleate 0.5% at completion of surgery, the normal group (n = 25) again had IOP significantly lower than those of the glaucoma (n = 15) and exfoliation syndrome (n = 20) groups (P<0.001). Treatment with timolol maleate 0.5% significantly changed postoperative IOP over time in the glaucomatous eyes (P = 0.003), but it made no difference in the exfoliation syndrome (P = 0.4) or normal (P = 0.5) eyes. Intraocular pressure > 25 mmHg did not occur among normal eyes. Intraocular pressure > 25 mmHg and > 30 mmHg occurred in 10 (55%) and 5 (28%) glaucoma patients, respectively, and 5 (27%) and 2 (11%) exfoliation syndrome patients, respectively. Timolol maleate 0.5% eliminated IOP spikes > 30 mmHg and reduced the frequency of IOP > 25 mmHg in both groups to 14% in the glaucoma group and 5% in the exfoliation syndrome group. Most IOP elevation occurred at 4 hours postoperatively. The mean IOP was <20 mmHg in all groups 1 day postoperatively.

CONCLUSIONS

Medically well-controlled glaucoma patients and patients with exfoliation syndrome may experience IOP elevation shortly after cataract surgery. Instillation of timolol maleate 0.5% at the end of the procedure in this series eliminated IOP > 30 mmHg, but IOP elevation below that level can still occur.

Postoperative course of intraocular pressure after cataract surgery with combined primary posterior capsulorhexis and posterior optic buttonholing

PURPOSE

To evaluate the natural course of intraocular pressure (IOP) after cataract surgery with combined primary posterior continuous curvilinear capsulorhexis (PPCCC) and posterior optic buttonholing (POBH) of the intraocular lens (IOL) in adult patients.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

Fifty consecutive patients with age-related cataract awaiting cataract surgery under topical anesthesia in both eyes were enrolled prospectively. In randomized order, cataract surgery with combined PPCCC and POBH was performed in 1 eye. In the fellow eye, cataract surgery was performed conventionally with in-the-bag IOL implantation and the posterior lens capsule kept intact. Standardized IOP measurements by Goldmann applanation tonometry were performed 1, 2, 4, 6, 8, and 24 hours postoperatively. Follow-up IOP measurements were taken at 1 week and 1 month. Twenty-five patients received 1-time IOP-lowering medication immediately after cataract surgery; the other 25 did not receive IOP-lowering drops.

RESULTS

During the first 24 hours postoperatively, no significant differences in IOP were observed between the PPCCC-POBH group and the conventional surgery group (P>.05). No IOP peaks greater than 27 mm Hg were observed in any eye. One week and 1 month postoperatively, no significant differences in IOP were found between groups (P>.05). The use of IOP-lowering drops significantly reduced postoperative IOP. However, no IOP spikes >27 mm Hg were found with and without the use of IOP-lowering drops.

CONCLUSION

The course of IOP after cataract surgery with combined PPCCC and POBH showed the technique to be as safe as conventional cataract surgery with in-the-bag IOL implantation.

Intraocular pressure and foveal thickness after phacoemulsification

PURPOSE

To evaluate the natural course of intraocular pressure (IOP) and foveal thickness during the postoperative period, and the correlation between them.

DESIGN

Prospective observational case series.

METHODS

This institutional study comprised 30 eyes of 30 cataract patients scheduled for phacoemulsification. IOP and foveal thickness by optical coherence tomography (OCT) were measured preoperatively and three, six, nine, 12, 15, 18, 21, 24 hours, five days, one month, and two months postoperatively.

RESULTS

The IOP was 4.7 +/- 2.4 mm Hg at three hours postoperatively. The IOP increased to 23.4 +/- 8.1 mm Hg at six hours and 23.5 +/- 7.3 mm Hg at nine hours postoperatively. The IOP was 1.9 mm Hg lower at one month or two months postoperatively than preoperatively. The foveal thickness was 202.1 +/- 19.2 microm and significantly higher at three hours postoperatively, and was 182.3 +/- 20.5 microm, 183.2 +/- 22.3 microm, and significantly lower at nine and 12 hours postoperatively than preoperatively. The correlation between mean IOP and mean foveal thickness is statistically significant. Fovea thickness (microns) = 207.0476 - 1.019759 x IOP (mm Hg), P value < .0001, adjusted R(2) = .8699.

CONCLUSIONS

We found initial hypotony, an IOP spike during six to nine hours, and a decrease of IOP at one month and two months postoperatively. An initial increase of the foveal thickness, a significant reduction at nine hours and 12 hours, and an equivocal increase at one month or two months postoperatively were also noted. A significant negative correlation between IOP and foveal thickness was shown.

Natural course of intraocular pressure after cataract surgery with sodium hyaluronate 1% versus hydroxypropylmethylcellulose 2%

PURPOSE

To investigate the natural course of intraocular pressure (IOP) after small-incision cataract surgery with sodium hyaluronate 1% versus hydroxypropylmethylcellulose 2%.

DESIGN

Randomized clinical trial.

PARTICIPANTS

Eighty eyes of 40 consecutive patients with bilateral age-related cataract.

METHODS

The patients were assigned randomly to receive sodium hyaluronate 1% or hydroxypropylmethylcellulose 2% during cataract surgery in the first eye. The second eye received the other ophthalmic viscosurgical device. The IOP was measured preoperatively and 30 minutes; 1, 2, 3, 4, 6, 8, and 20 to 24 hours; and 1 week postoperatively.

MAIN OUTCOME MEASURE

Postoperative IOP increase.

RESULTS

The highest mean IOP increase occurred at 8 hours postoperatively (5.3+/-6.4 mmHg) in the sodium hyaluronate 1% group and at 2 hours postoperatively (7.8+/-6.1 mmHg) in the hydroxypropylmethylcellulose 2% group. Overall, the IOP increase was higher with hydroxypropylmethylcellulose 2% (P = 0.005). Intraocular pressure spikes to > or =30 mmHg occurred in 5 eyes (13%) in the sodium hyaluronate 1% group and 13 eyes (33%) in the hydroxypropylmethylcellulose 2% group.

CONCLUSIONS

Sodium hyaluronate 1% and hydroxypropylmethylcellulose 2% caused significant IOP increases during the first 8 hours after cataract surgery. A single measurement at 6 hours postoperatively could detect all IOP spikes in the sodium hyaluronate 1% group. In the hydroxypropylmethylcellulose 2% group, a single measurement at 2 hours postoperatively could detect two thirds of IOP spikes.

Comparison of Ultrasonic Energy Expenditures and Corneal Endothelial Cell Density Reductions During Modulated and Non-Modulated Phacoemulsification

BACKGROUND AND OBJECTIVE

To compare the Legacy 20000 Advantec continuous and Infiniti hyperpulse modes (Alcon Laboratories, Fort Worth, TX) with respect to average power, machine-measured phacoemulsification time, total stopwatch real time spent within the phacoemulsification process, balanced salt solution (BSS) volume, and corneal endothelial cell density losses.

PATIENTS AND METHODS

A background study was done of consecutive patients operated on with the Legacy (n = 60) and Infiniti (n = 40) machines programmed with identical parameters and using the continuous mode only. A primary study of another set of consecutive cases was operated on using the Legacy (n = 87) and Infiniti (n = 94) with the same parameters, but using the hyperpulse mode during quadrant removal with the Infiniti. Measurements for each set included average power and phacoemulsification time with corneal endothelial cell densities, BSS volume, and time spent in the phacoemulsification process.

RESULTS

Similarities were found in the background study for average power percent and average minutes of phacoemulsification time. In the primary study, similarities were found for total minutes in the phacoemulsification process, BSS usage, and ECD losses, and differences were found for average power percent (P< .001) and machine-measured phacoemulsification minutes (P< .001).

CONCLUSIONS

The Legacy and Infiniti performed similarly in continuous mode. With the Infiniti hyperpulse mode, a total ultrasonic energy reduction of 66% was noted. The machines required the same amount of total stopwatch measured time to accomplish phacoemulsification and produced the same 5% corneal endothelial cell loss. Therefore, clinically, these two machines behave in a comparable manner relative to safety and effectiveness.

Incidence of Intraocular Pressure Spike and Other Adverse Events after Vitreoretinal Surgery

PURPOSE

To determine the incidence of significant postoperative intraocular pressure (IOP) elevation and other adverse medical events during the first postoperative day in patients undergoing inpatient vitreoretinal surgery.

DESIGN

Noncomparative interventional case series.

PARTICIPANTS

Two hundred two consecutive patients were admitted prospectively as inpatients after vitreoretinal surgery (vitrectomy and/or scleral buckling).

METHODS

Intraocular pressure was measured preoperatively, 5 to 12 hours postoperatively, and on postoperative day 1. Additionally, pain, nausea, and serious systemic adverse events were monitored.

RESULTS

Seventeen patients (8.4%) had a 5- to 12-hour IOP measurement above 29 mmHg. Thirty patients (14.8%) had a postoperative day 1 IOP measurement above 29 mmHg. Three patients (1.5%) required a parenteral narcotic to achieve adequate analgesia. Nine patients (4.5%) utilized a parenteral antiemetic for nausea control. Six patients (3.0%) had a hyperglycemic event. No serious systemic adverse events occurred in the early postoperative period.

CONCLUSIONS

The incidence of a significant IOP spike or systemic adverse events in the early postoperative period in patients undergoing vitreoretinal surgery is low.

Natural Course of Intraocular Pressure after Cataract Surgery with Sodium Chondroitin Sulfate 4%–Sodium Hyaluronate 3% (Viscoat)

PURPOSE

To investigate the natural course of intraocular pressure (IOP) and its peak after small-incision cataract surgery with chondroitin sulfate 4%-sodium hyaluronate 3% (Viscoat, Alcon Laboratories, Inc., Fort Worth, TX).

DESIGN

Observational case series.

PARTICIPANTS

This prospective study comprised 40 eyes of 40 consecutive cataract patients scheduled for small-incision cataract surgery.

METHODS

Cataract surgery was performed with sodium chondroitin sulfate 4%-sodium hyaluronate 3% as the ophthalmic viscosurgical device, which was removed as completely as possible from the eye at the end of surgery. The IOP was measured preoperatively and 30 minutes; 1, 2, 3, 4, 6, 8, and 20 to 24 hours; and 1 week postoperatively.

MAIN OUTCOME MEASURES

Postoperative IOP increase.

RESULTS

The mean IOP increased significantly at all observation times during the first 20 to 24 hours, with a peak increase of 13.4+/-9.4 mmHg after 1 hour (P<0.05). In all, 28 eyes (70%) had an IOP spike to 30 mmHg or higher. Sixty-eight percent of these spikes occurred at 30 minutes as well as at 1 hour and 2 hours postoperatively. At 20 to 24 hours, no eye had an IOP spike to 30 mmHg or higher.

CONCLUSIONS

Significant IOP increases were found during the first 24 hours, peaking at 1 hour after surgery. With a single postoperative IOP measurement, between 30 minutes and 2 hours after surgery, two thirds of these IOP spikes could be detected. To detect all IOP spikes, a second measurement between 4 and 6 hours after surgery would be necessary.

Study of Ocular Transport of Drugs Released from an Intravitreal Implant Using Magnetic Resonance Imaging

Ensuring optimum delivery of therapeutic agents in the eye requires detailed information about the transport mechanisms and elimination pathways available. This knowledge can guide the development of new drug delivery devices. In this study, we investigated the movement of a drug surrogate, Gd-DTPA (Magnevist) released from a polymer-based implant in rabbit vitreous using T1-weighted magnetic resonance imaging (MRI). Intensity values in the MRI data were converted to concentration by comparison with calibration samples. Concentration profiles approaching pseudosteady state showed gradients from the implant toward the retinal surface, suggesting that diffusion was occurring into the retinal-choroidal-scleral (RCS) membrane. Gd-DTPA concentration varied from high values near the implant to lower values distal to the implant. Such regional concentration differences throughout the vitreous may have clinical significance when attempting to treat ubiquitous eye diseases using a single positional implant. We developed a finite element mathematical model of the rabbit eye and compared the MRI experimental concentration data with simulation concentration profiles. The model utilized a diffusion coefficient of Gd-DTPA in the vitreous of 2.8 x 10(-6) cm2 s(-1) and yielded a diffusion coefficient for Gd-DTPA through the simulated composite posterior membrane (representing the retina-choroidsclera membrane) of 6.0 x 10(-8) cm2 s(-1). Since the model membrane was 0.03-cm thick, this resulted in an effective membrane permeability of 2.0 x 10(-6) cm s(-1). Convective movement of Gd-DTPA was shown to have minimal effect on the concentration profiles since the Peclet number was 0.09 for this system.

Comparing the effects of travoprost and brinzolamide on intraocular pressure after phacoemulsification

PURPOSE

To evaluate the intraocular pressure (IOP) lowering effect of travoprost and brinzolamide within the first 24 h after phacoemulsification cataract surgery.

METHODS

This prospective, randomized, double-masked, controlled study comprised 90 eyes of 90 consecutive patients with senile cataract who had uneventful phacoemulsification surgery. Eyes in the first group received travoprost 0.0015%, second group received brinzolamide 1%. Eyes in the third group received balanced salt solution and were used as control. One drop was instilled immediately after surgery. IOP was measured 24 h preoperatively, 6 and 24 h postoperatively. Analysis of variance, Student's-t and chi2-tests were used for statistical analyses.

RESULTS

Preoperatively IOP was not significantly different among the three groups (P = 0.653). At 6 and 24 h postoperatively IOP was lower in both travoprost and brinzolamide group when compared to control group (P = 0.018 and 0.015 at 6 h, P = 0.010 and 0.007 at 24 h between travoprost and brinzolamide group was not significant (P = 0.744 at 6 h and P = 0.672 at 24 h).

CONCLUSION

Both travoprost and brinzolamide significantly lowered IOP after small incision phacoemulsification cataract surgery within the first 24 h without any side effect.

Empty-bag technique for acrylic intraocular lens implantation using Healon5

PURPOSE

To determine how often the empty-bag technique (EBT) for injecting an acrylic foldable intraocular lens (IOL) into the capsular bag using Healon5 (sodium hyaluronate 2.3%) will require a 2-compartment technique to remove the ophthalmic viscosurgical device (OVD) and compare this with that of a standard injection method using Healon5.

SETTING

Cincinnati Eye Institute and Ambulatory Surgical Center, Cincinnati, Ohio, USA.

METHODS

Forty-one eyes of 40 patients were randomly assigned to 1 of 2 groups. In Group A, standard capsular bag expansion was performed with Healon5 before implantation of an acrylic posterior chamber (PC) IOL. In Group B, Healon5 was placed in the anterior chamber followed by balanced salt solution expansion of the capsular bag before acrylic PC IOL implantation. In all patients, complete OVD removal was attempted with the automated aspiration tip anterior to the optic (rock 'n roll technique). The number of patients in each group who required placement of the aspiration tip posterior to the optic for complete removal was compared. Early postoperative intraocular pressure (IOP) was also compared.

RESULTS

In Group A, 15 (75%) of 20 eyes required placement of the aspiration tip posterior to the optic for complete OVD removal and in Group B, 1 (0.05%) of 20 eyes. The postoperative IOP was similar in both groups.

CONCLUSIONS

The EBT decreased the likelihood that a 2-compartment OVD removal method would be necessary when using Healon5 for acrylic PC IOL implantation. The limitations of this new technique must be fully understood before it is used.

Removal times and techniques of a viscoadaptive ophthalmic viscosurgical device

PURPOSE

To analyze removal techniques for Healon5 (sodium hyaluronate 2.3%).

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Charleston, South Carolina, USA, and Department of Ophthalmology, Ruprecht-Karls-University, Heidelberg, Germany.

METHODS

In a standardized laboratory setup, the Miyake-Apple posterior view video technique in human autopsy eyes was used to evaluate removal of an ophthalmic viscosurgical device (OVD) from capsular bags implanted with poly(methyl methacrylate), silicone, and acrylic intraocular lenses (IOLs). Healon5 was stained with fluorescein for better visualization. Open-sky preparation and an Alcon Legacy Series 20000 phaco machine with a flow rate of 25 mL/minute and a vacuum setting of +500 mm Hg (maximum irrigation/aspiration [I/A]) were used. With Technique 1, the I/A tip was placed on the center of the IOL and maximum aspiration was applied. With Technique 2 (modified rock 'n roll technique), the I/A tip was moved in quick circular movements on top of the IOL to break the OVD chains and facilitate aspiration.

RESULTS

With Technique 1, the mean removal time was 59.0 seconds +/- 23.1 (SD) and with Technique 2, 23.6 +/- 10.3 seconds (P =.004). The removal time of Healon5 correlated with the IOL material. With Technique 2, removal was fastest with silicone IOLs (13.5 +/- 2.1 seconds) followed by PMMA IOLs (17.5 +/- 2.1 seconds). With acrylic IOLs, remnants of the OVD trapped behind the IOL optic resulted in a longer removal time of 34.1 +/- 1.2 seconds.

CONCLUSIONS

Healon5 was completely removed from the capsular bag with the modified rock 'n roll technique. With acrylic IOLs, remnants can be trapped behind the optic and may be overlooked with an unstained OVD. Aspiration behind the optic is recommended with this IOL type.

Effect of a fixed dorzolamide–timolol combination on intraocular pressure after small-incision cataract surgery with Viscoat

PURPOSE

To evaluate the effect of a fixed dorzolamide-timolol combination (Cosopt) on intraocular pressure (IOP) after small-incision cataract surgery with sodium chondroitin sulfate 4%-sodium hyaluronate 3% (Viscoat).

SETTING

Department of Ophthalmology, University of Vienna, Vienna, Austria.

METHODS

This prospective randomized study comprised 76 eyes of 38 patients scheduled for small-incision cataract surgery in both eyes. Patients were randomized to receive 1 drop of the fixed dorzolamide-timolol combination in 1 eye or no treatment (control) immediately after cataract surgery. The fellow eye received the other assigned treatment. Cataract surgery was performed with Viscoat in an identical fashion in both eyes. The IOP was measured preoperatively and 6 hours, 20 to 24 hours, and 1 week postoperatively.

RESULTS

Six hours after surgery, the mean increase in IOP was significantly lower in the dorzolamide-timolol group than in the control group (4.3 mm Hg +/- 5.6 [SD] versus 8.4 +/- 6.1 mm Hg; P =.003). Two eyes in the dorzolamide-timolol group and 9 in the control group had IOP spikes of 30 mm Hg or higher (P =.022). Twenty to 24 hours after surgery, the mean IOP change was -2.6 +/- 3.3 mm Hg in the dorzolamide-timolol group and 1.5 +/- 3.2 mm Hg in the control group (P<.001).

CONCLUSIONS

The fixed dorzolamide-timolol combination was effective in reducing IOP 6 hours and 20 to 24 hours after cataract surgery. However, it did not prevent Viscoat-induced IOP spikes of 30 mm Hg or higher.

Hydroxypropyl methylcellulose: A better submucosal fluid cushion for endoscopic mucosal resection

BACKGROUND

Formation of a submucosal fluid cushion has become integral to endoscopic mucosal and polyp resection. Solutions available for injection into the submucosa of the GI tract create short-lasting submucosal fluid cushions or are costly. The feasibility, durability, and histologic response to submucosal fluid cushions created by injection of hydroxypropyl methylcellulose were studied in the esophagus of pigs.

METHODS

Thirty-six esophageal submucosal fluid cushions created with hydroxypropyl methylcellulose were studied in 12 animals divided in 2 groups of 6 animals each. In Group I, 18 submucosal fluid cushions were created by submucosal injection of hydroxypropyl methylcellulose followed by tattooing. In Group II, 18 submucosal fluid cushions were created by submucosal injection of hydroxypropyl methylcellulose, with sites marked by an endoscopically placed suture. In all cases, the duration of the submucosal fluid cushion was measured. After 7 days, submucosal fluid cushion sites were assessed by EGD, necropsy, and histologic evaluation.

RESULTS

The mean submucosal fluid cushion duration was 36 minutes (3-45 minutes) and 38 minutes (5-45 minutes) for, respectively, Groups I and II. EGD and necropsy after 1 week showed normal-appearing mucosa at the site of all submucosal fluid cushions in both groups. Some Group I animals additionally had nodules at the tattoo sites. Histologic assessment demonstrated minimal alterations in 33 of 36 (92%) submucosal fluid cushion sites and localized mild inflammatory reaction in 3 of 36 (8%). In Group I, 8 of 18 (44%) tattoo sites exhibited a significant inflammatory reaction, including 3 abscesses.

CONCLUSIONS

Hydroxypropyl methylcellulose creates a long-lasting submucosal fluid cushion with minimal tissue reaction and should be considered a low-cost option for creating submucosal fluid cushions. The use of tattooing with carbon black should be carefully considered when histologic study is required to assess potential inflammatory tissue responses to an invasive technique or instillation of foreign material in the GI tract.