Postoperative Intraocular Pressure Changes Research Articles

Lens Position Parameters as Predictors of Intraocular Pressure Reduction After Cataract Surgery in Nonglaucomatous Patients With Open Angles.

To evaluate the relationship between lens position parameters and intraocular pressure (IOP) reduction after cataract surgery in nonglaucomatous eyes with open angles. The main outcome of the prospective study was percentage of IOP change, which was calculated using the preoperative IOP and the IOP 4 months after cataract surgery in nonglaucomatous eyes with open angles. Lens position (LP), defined as anterior chamber depth (ACD) + 1/2 lens thickness (LT), was assessed preoperatively using parameters from optical biometry. Preoperative IOP, central corneal thickness, ACD, LT, axial length (AXL), and the ratio of preoperative IOP to ACD (PD ratio) were also evaluated as potential predictors of percentage of IOP change. The predictive values of the parameters we found to be associated with the primary outcome were compared. Four months after cataract surgery, the average IOP reduction was 2.03 ± 2.42 mm Hg, a 12.74% reduction from the preoperative mean of 14.5 ± 3.05 mm Hg. Lens position was correlated with IOP reduction percentage after adjusting for confounders (P = 0.002). Higher preoperative IOP, shallower ACD, shorter AXL, and thicker LT were significantly associated with percentage of IOP decrease. Although not statistically significant, LP was a better predictor of percentage of IOP change compared to PD ratio, preoperative IOP, and ACD. The percentage of IOP reduction after cataract surgery in nonglaucomatous eyes with open angles is greater in more anteriorly positioned lenses. Lens position, which is convenient to compute by basic ocular biometric data, is an accessible predictor with considerable predictive value for postoperative IOP change.

Supraciliary Micro-stent Implantation for Open-Angle Glaucoma Failing Topical Therapy: 1-Year Results of a Multicenter Study

To evaluate the safety and efficacy of a supraciliary micro-stent (CyPass Micro-Stent; Transcend Medical, Menlo Park, California, USA) for surgical treatment of glaucoma in patients refractory to topical medications. Multicenter, single-arm interventional study. Patients with open-angle glaucoma (Shaffer Grade 3 and 4) and uncontrolled medicated intraocular pressure (IOP) >21mm Hg at baseline and candidates for conventional glaucoma surgery were enrolled. Glaucoma medications were discontinued at surgery and resumed at investigator discretion. CyPass Micro-Stent implantation was completed in all patients using a standard clear corneal approach. Adverse events, postoperative IOP changes, and need for IOP-lowering medications during the first 12 postoperative months (12M) were monitored. Sixty-five eyes were enrolled, and 55 were available at 12M, accounting for loss to follow-up and early termination. Baseline IOP was 24.5 ± 2.8mm Hg, and the mean number of medications recorded was 2.2 ± 1.1. There were no serious intraoperative events or major adverse events (eg, retinal or choroidal detachment, persistent uveitis, persistent hyphema, hypotony maculopathy). The most common adverse events included IOP increases >30mm Hg beyond 1month (11%, 7/65), transient hyphema (6%, 4/65), and cataract progression (12%, 5/41 phakic eyes). Mean IOP was 16.4 ± 5.5mm Hg at 12months-a 34.7% reduction (P < .0001). Mean medication usage also decreased from baseline to a mean of 1.4 ± 1.3 medications at 12M (P= .002). In eyes originally indicated for conventional glaucoma surgery, no secondary surgery was performed in 83% (53/64). Supraciliary stenting with the CyPass Micro-Stent effectively lowers IOP as a surgical treatment for glaucoma, precluding the need for more invasive glaucoma surgery in >80% of patients at 1 year, therebyreducing postoperative glaucoma surgical complications.

Lens Extraction for Management of Coexisting Cataract and Post-filtering Surgery Ocular Hypotony.

Purpose:To evaluate the safety and efficacy of phacoemulsification for management of post-filtering ocular hypotony.Methods:This prospective interventional case series study recruited 21 consecutive patients with an established diagnosis of ocular hypotony with or without maculopathy. Clear corneal incision phacoemulsification was done for all patients. Nineteen cases that completed a follow-up of at least 6 months were considered for final analysis.Results:Mean baseline intraocular pressure (IOP) was 2.95 ± 1.43 mm Hg, which increased to 8.84 ± 4.67 mm Hg at 6 months (P < 0.001). Hypotony was resolved in 13 cases (68%) at 6 months while 6 cases (32%) showed persistent hypotony at this time point. Postoperative IOP change at all follow-up time points was not correlated with patient age, time interval between filtering surgery and phacoemulsification, baseline IOP, baseline anterior chamber depth and IOP on the first postoperative day. Three cases (16%) showed filtering bleb failure with dramatic IOP rise around the first postoperative month and required glaucoma medication for IOP control. No significant intra- or postoperative complications were noted.Conclusion:Cataract surgery alone seems promising in resolving hypotony in patients with post-filtering ocular hypotony, and can be considered as an effective treatment modality before proceeding to more complicated procedures.

Factors that Influence Intraocular Pressure Changes after Myopic and Hyperopic LASIK and Photorefractive Keratectomy: A Large Population Study

To describe the factors that influence the measured intraocular pressure (IOP) change and to develop a predictive model after myopic and hyperopic LASIK and photorefractive keratectomy (PRK) in a large population. Retrospective, observational case series. Patients undergoing primary PRK or LASIK with a refractive target of emmetropia between January 1, 2008, and October 5, 2011. The Optical Express database was queried for all subjects. Data were extracted on procedure specifics, preoperative central corneal thickness (CCT), IOP (using noncontact tonometry), manifest refraction, average keratometry, age, gender, and postoperative IOP at 1 week, 1 month, and 3 months. A linear mixed methods model was used for data analysis. Change in IOP from preoperatively to 1 month postoperatively. A total of 174 666 eyes of 91 204 patients were analyzed. Hyperopic corrections experienced a smaller IOP decrease than myopic corrections for both PRK and LASIK (P<0.0001). Patients who underwent LASIK had a 0.94 mmHg (95% confidence interval [CI], 0.89-0.98) greater IOP decrease than patients who underwent PRK (P<0.0001), reflecting the effect of the lamellar flap. The decrease in IOP was linearly related to preoperative manifest spherical equivalent (MSE) for myopic PRK and LASIK (P<0.0001), weakly correlated with preoperative MSE after hyperopic LASIK, and not related to preoperative MSE after hyperopic PRK. The single greatest predictor of IOP change was preoperative IOP across all corrections. By using the available data, a model was constructed to predict postoperative IOP change at 1 month; this was able to explain 42% of the IOP change after myopic LASIK, 34% of the change after myopic PRK, 25% of the change after hyperopic LASIK, and 16% of the change after hyperopic PRK. Myopic procedures lower measured IOP more than hyperopic procedures; this decrease was proportional to the amount of refractive error corrected. Independent of the refractive correction, the creation of the lamellar LASIK flap decreased measured IOP by 0.94 mmHg. A best-fit model for IOP change was developed that may allow better interpretation of post-laser vision correction IOP values.

Intraocular Pressure Lowering Effect of Orbital Decompression is Related to Increased Venous Outflow in Graves Orbitopathy

Purpose: To investigate the effects of combined orbital bone and fat decompression on intraocular pressure (IOP) and superior ophthalmic vein blood flow velocity (SOV-BFV), and their association with the clinical features of Graves orbitopathy (GO).Methods: During the 2002–2008 period, 72 eyes of 36 GO cases demonstrating moderate to severe orbitopathy were evaluated according to their clinical features as: cases with or without dysthyroid optic neuropathy (DON), and underwent orbital decompression. A control group comprised 40 eyes of 20 healthy subjects. In both groups, a full ophthalmic examination including IOP and Hertel measurements was performed, and SOV-BFV was analyzed with color Doppler imaging. Examinations were repeated after orbital decompression in GO patients.Results: All the cases demonstrated clinical features of inactive disease. Among the patients 24 of 72 eyes (33.3%) showed clinical features of DON. After surgery, the mean decrease in Hertel values was 6.2 ± 1.8 mm (p = 0.001). The mean decrease in IOP was 3.0 ± 1.7 mmHg (from 17.3 ± 2.7 to 14.3 ± 2.0 mmHg) after orbital decompression where the post-operative values were comparable with the control group (12.9 ± 1.4 mmHg, p = 0.36). The mean increase in SOV-BFV achieved with decompression was 1.2 ± 0.6 cm/s (from 4.8 ± 1.7 to 6.0 ± 1.8 cm/s) and post-operative SOV-BFV values were also comparable with the control group (6.6 ± 1.3 cm/s, p = 0.26). The increase in SOV-BFV in cases with DON did not differ from cases without DON (p = 0.32), however, post-operative SOV-BFV of cases with DON was stil lower than cases without DON (p = 0.035).Conclusions: Combined orbital bone and fat decompression significantly reduced the IOP levels and increased the SOV-BFV in GO. This could be the confirmative finding of prediction that elevated IOP in GO is associated with increased episcleral venous pressure. The post-operative changes in IOP and SOV-BFV show differences regarding the clinical features of disease.

Early postoperative safety and surgical outcomes after implantation of a suprachoroidal micro-stent for the treatment of open-angle glaucoma concomitant with cataract surgery

To evaluate the safety of a new suprachoroidal device, the Cypass micro-stent, for the surgical treatment of open-angle glaucoma (OAG) implanted in conjunction with cataract surgery. Multicenter clinical study. Prospective interventional case series. This is an interim report of an ongoing safety study. Patients with OAG glaucoma (Shaffer grade 3 and 4) who were also candidates for cataract surgery in the affected eye had standard phacoemulsification followed by micro-stent implantation in the supraciliary space. Included were patients with uncontrolled (≥ 21 mm Hg, Cohort 1) or controlled (<21 mm Hg, Cohort 2) medicated intraocular pressure (IOP) at baseline. Glaucoma medications were discontinued at surgery and resumed at the discretion of each investigator. Measures included adverse events/complications and postoperative changes in IOP or medication. The mean baseline medicated IOP was 21.1 mm Hg ± 5.91 (SD); the mean number of IOP-lowering medications was 2.1 ± 1.1 (N = 184). There were no major events such as retinal or choroidal detachment or endophthalmitis. The most common complications were transient early hypotony (13.8%) and transient IOP increase (10.5%). Uncontrolled patients (n = 57) had a 37% IOP reduction (P<.001), with more than a 50% reduction in glaucoma medications at 6 months (P<.001). Intraocular pressure-controlled patients (n = 41) had a 71.4% reduction in glaucoma medications (P<.001). Initial clinical experience with the new micro-stent showed a low rate of surgical complications with concomitant decreases in IOP and/or glaucoma medications.

Preoperative Factors Associated with IOP Reduction After Cataract Surgery

To identify preoperative factors associated with postoperative intraocular pressure (IOP) reduction after phacoemulsification cataract extraction in patients with primary open-angle glaucoma (POAG) treated at a Veterans Affairs Medical Center. Examination records of 103 eyes of 75 patients with POAG who underwent uncomplicated phacoemulsification cataract extraction were reviewed. Preoperative data collected for analysis included IOP, number of glaucoma medications, spherical equivalent refractive errors, central corneal thickness, anterior chamber depth, and axial length. The IOPs measured 3 to 6 months after surgery were used to calculate the change in IOP after cataract extraction. Statistical analysis was performed to identify preoperative factors associated with postoperative IOP reduction. The mean postoperative IOP reduction was 1.8 ± 3.5 mm Hg (p < 0.001). Seventy-four percent of eyes (76 of 103) had decreased IOP after cataract surgery. Eight percent of eyes (8 of 103) had no change in IOP. Eighteen percent of eyes (19 of 103) had increased IOP after cataract surgery. The mean preoperative IOPs for eyes with increased, same, and decreased postoperative IOPs were 12 ± 2.2 mm Hg, 14.0 ± 2.3 mm Hg, and 16.4 ± 3.1 mm Hg, respectively. The mean postoperative IOPs change for eyes with increased and decreased postoperative IOPs were +2.7 ± 2.1 mm Hg and -3.7 ± 2.5 mm Hg, respectively. Preoperative IOP was the only preoperative factor significantly associated with postoperative IOP reduction (p < 0.001). Preoperative IOP was the only factor significantly associated with postoperative IOP reduction after cataract surgery in POAG patients. A higher preoperative IOP was strongly associated with a greater postoperative IOP reduction. Patients with low preoperative IOPs tended to have minimal reduction or even a mild increase in postoperative IOPs. These findings have important implications when considering combined cataract extraction and filtration surgery for POAG patients.

Comparison of postoperative intraocular pressure changes between 23-gauge transconjunctival sutureless vitrectomy and conventional 20-gauge vitrectomy

To compare the intraocular pressure (IOP) after 23-gauge transconjunctival sutureless vitrectomy (TSV) and conventional 20-gauge vitrectomy for various vitreoretinal diseases. This was a retrospective interventional case series including 338 cases of 23-gauge TSV and 476 cases of 20-gauge vitrectomy with minimum follow-up period of 1 month. Postoperative 1 day, 1 week and 1 month IOPs were compared. Multiple regression analysis to assess the actual effect of gauge of vitrectomy on postoperative IOP was performed including intraoperative and postoperative factors influencing postoperative IOP as covariates. The mean IOP of 20-gauge vitrectomy was significantly higher than that of 23-gauge TSV (20.6 ± 8.02 mm Hg vs 12.8 ± 4.48 mm Hg, P<0.001) at postoperative day 1, but the differences were not significant at postoperative 1 week and 1 month. The IOP pattern of 23-gauge TSV demonstrated more stable course than that of 20-gauge vitrectomy. At 1 day post vitrectomy, the incidence of hypertony was higher in 20-gauge, whereas that of hypotony was higher in 23-gauge. Among risk factors, the 20-gauge vitrectomy showed the strongest association with postoperative 1 day IOP rise. Twenty-three-gauge TSV has stable and lower IOP in the early postoperative period than the 20-gauge vitrectomy. In patients whose retina and optic nerves are vulnerable to higher or fluctuating IOP, 23-gauge TSV may be more beneficial.

Selective laser trabeculoplasty in Egyptian patients with primary open-angle glaucoma

Purpose:To assess the change in intraocular pressure (IOP) in Egyptian patients after selective laser trabeculoplasty (SLT) as a primary or adjunctive treatment for primary open-angle glaucoma (POAG).Materials and Methods:One hundred and six eyes with POAG were enrolled in this prospective study. Patients were divided into two groups: recently diagnosed cases with no preoperative medications (group 1) and; patients with confirmed glaucoma on medical therapy (group 2). All patients underwent 360° SLT. Patients were evaluated to 18 months postoperatively. Data were analyzed on postoperative changes in IOP, number of medications and complications. A P-value less than 0.05 was statistically significant.Results:A statistically significant drop in IOP occurred, from 19.55 ± 4.8 mmHg preoperatively, to16.03 ± 2.8 mmHg postoperatively (P< 0.001). Each group had a statistically significant drop in IOP (P< 0.001). There was a statistically significant decrease in the number of medications in group 2 from 2.25 ± 0.97 medications preoperatively to 1.0 ± 1.3 medications postoperatively (P=0.004). No serious complications occurred for the duration of the study.Conclusion:SLT can be safely and effectively used as primary or adjunctive therapy for the treatment of POAG.

Intraocular pressure changes following Descemet’s stripping with endothelial keratoplasty

To evaluate the postoperative changes in intraocular pressure (IOP) following Descemet's stripping with endothelial keratoplasty (DSEK). A retrospective chart review of 45 eyes that underwent DSEK for the treatment of corneal edema induced by aphakic or pseudophakic bullous keratopathy (ABK/PBK) and Fuchs' endothelial dystrophy. A mean baseline IOP was obtained at three different preoperative visits using Tono-Pen XL tonometer. This baseline pressure was compared to IOPs obtained at postoperative months 1, 3, 6 and 12. Intraocular pressure increased from a mean preoperative value of 15.6 +/- 4.2 mmHg to 15.9 +/- 5.8 mmHg in the first postoperative month; 17.0 +/- 5.7 mmHg at 3 months; 18.1 +/- 6.2 mmHg at 6 months and 16.8 +/- 4.7 mmHg at 1 year. These pressure differences were considered statistically significant, p = 0.0074 (repeated measures ANOVA). Eyes diagnosed with ABK/PBK (n = 20) showed a significant rise in IOP only noted after the 3(rd) month that peaked at 6 months, p = 0.0001 (repeated measures ANOVA). A subgroup of patients with a diagnosis of Fuchs' endothelial dystrophy (n = 25), showed no statistically significant changes in IOP at 1 year follow-up; p = 0.9103 (repeated measures ANOVA). In a subgroup of eyes with a diagnosis of glaucoma or ocular hypertension (n = 13), a statistically significant increase in IOP was noted after 1 year of follow-up. Mean IOP raised from a preoperative mean value of 16.0 +/- 3.7 mHg to 19.0 +/- 5.3 mmHg at 1 year; p = 0.0074 (repeated measures ANOVA). DSEK induced statistically significant IOP increases in the early postoperative period with a tendency to higher pressures after the 3(rd) month of follow-up. Patients with a preoperative diagnosis of Fuchs' endothelial dystrophy did not show a statistically significant increase in IOP compared to a baseline mean preoperative value. The difference between statistically significant and clinically significant IOP increase is yet to be established.

A comparative study of postoperative intraocular pressure changes in small incision vs conventional extracapsular cataract surgery

To compare short- and long-term IOP changes in small incision cataract surgery (SICS) vs conventional extracapsular cataract surgery (CECS). A total of 232 eyes of as many patients undergoing cataract surgery were randomized to SICS or CECS. Sixteen eyes had to be excluded out of the study. IOP was recorded preoperatively and postoperatively on day 1, 2, and 7; and then after 1, 3, and 6 months. Only 160 eyes remained under 6-month follow-up, out of which 48 had CECS and remaining 112, SICS. Results were analysed statistically (repeated measure ANOVA, multiple comparisons). A significantly higher IOP was observed on day 1, 2, and 7 in both types of surgeries as compared to mean preoperative IOP. Variation in rise was more pronounced in CECS (nearly twofold) than in SICS (P<0.05). Maximum decrease in IOP occurred during the first week and it was more rapid in SICS than CECS. At 3 months, IOP was significantly higher than baseline in CECS but significantly lower in SICS. From 3 to 6 months, there was no further decrease in IOP in either type of surgery. IOP rises significantly on day one in CECS and SICS and thereafter comes down slightly by day 2 and rapidly by day 7. IOP rise is more pronounced in CECS than in SICS. After 1 week to 3 months, IOP decline is very gradual and thereafter ceases to decrease.

Reduction in admissions of patients with acute primary angle closure occurring in conjunction with a rise in cataract surgery in Taiwan

Using 8 year nationwide administrative data, this study sets out to investigate the relationship between the total number of cataract operations undertaken in Taiwan and admissions for acute primary angle closure (APAC). Monthly cataract surgery and APAC admission rates, per 100,000 of the population, were provided by 1997-2004 inpatient and outpatient data obtained from the Taiwanese National Health Insurance Research Database. The 3814 cases of APAC and 503 687 patients who had undergone cataract operations were categorized by age groups (40-49, 50-59, 60-69 and > or =70 years) and by gender. Spearman rank correlation coefficients were used to examine the direction and strength of the relationships. Throughout the study period, the admissions for APAC showed a steady decline from 630 cases in 1997 to 351 cases in 2004, while the number of cataract operations revealed a gradual increase from 26 600 in 1997 to 77 924 in 2004. The Spearman rank correlation coefficients showed significant inverse relationships between monthly APAC admission rates and monthly cataract operation rates for the total group (r = -0.407, P < 0.001), males (r = -0.330, P < 0.001), females (r = -0.444, P < 0.001), 40-49 year olds (r = -0.335, P < 0.001), 50-59 year olds (r = -0.497, P < 0.001) and 60-69 year olds (r = -0.417, P < 0.001). No significant inverse relationship was observed for the > or =70 age group. Significant inverse relationships were noted between the monthly APAC admission rates and the monthly cataract operation rates. We recommend that data should be collected from other regions and ethnic groups to determine the inter-relationships.

OCULAR SURFACE FLUID CONTAMINATION OF SUTURELESS 25-GAUGE VITRECTOMY INCISIONS

To determine whether 25-gauge transconjunctival sutureless vitrectomy incisions are more likely to allow the inflow of ocular surface fluid than sutured vitrectomy incisions. Four groups of cadaver eyes underwent three-port vitrectomy in a laboratory setup. Groups A and B had 25-gauge vitrectomy, with and without conjunctival displacement, respectively, and were left unsutured. Group C had 25-gauge vitrectomy with suturing of the sclerotomies. Group D had 20-gauge sutured vitrectomy. In all groups, India ink was applied to the ocular surface after the procedure, and the intraocular pressure (IOP) was varied to simulate postoperative IOP changes. Histology of the incisions was performed. Ink particles were identified in the wound in over two-thirds of eyes that underwent 25-gauge sutureless vitrectomy. Conjunctival displacement had no effect on ink ingress. Sutured 25- and 20-gauge incisions did not demonstrate ink particles in the wound. Twenty-five-gauge transconjunctival sutureless vitrectomy incisions, with or without conjunctival displacement, allowed the entry of ocular surface fluid into the eye in this laboratory model. Based on the limited number of eyes examined in this study, sutureless vitrectomy techniques may carry an increased risk of bacterial contamination that could predispose to endophthalmitis. Suturing may protect against ocular surface fluid ingress.

Direct Orbital Manometry in Normal and Fractured Orbits of Chinese Patients

This study measured direct orbital tension (DOT) in normal and fractured orbits of Chinese patients before and after orbital fracture repair, to investigate the changes in DOT and intraocular pressure (IOP) after surgery and to evaluate any correlation between them. DOT was directly measured by a specially designed orbitonometer before and after orbital fracture surgery in 40 cases of unilateral orbital fractures, using the contralateral eyes as a control group. All of the patients were submitted to orbital fracture repair and globe repositioning. IOP and ocular function were recorded preoperatively and postoperatively. DOT was 5.0 +/- 1.3 mm Hg (mean +/- SD) in the normal orbits. DOT was positively correlated with IOP (r = 0.56; P < .01). DOT and IOP were significantly decreased (s = 81, P = .01 and s = 49.5, P = .02, respectively) on the fractured orbit side. Postoperative DOT and IOP were significantly increased (s = 410, P < .01 and s = 390, P < .01, respectively). The preoperative to postoperative changes in both DOT and IOP were positively correlated (r = 0.54; P < .01). DOT can be measured safely using an orbital manometer in normal and fractured orbits. DOT and IOP increased significantly after orbital fracture surgery. DOT was well-correlated with IOP both preoperatively and postoperatively.

Midterm Results and the Problems of Nonpenetrating Lamellar Trabeculectomy with Mitomycin C for Japanese Glaucoma Patients

To present midterm results and problems pertaining to nonpenetrating lamellar trabeculectomy (NPT) with mitomycin C (MMC) for Japanese glaucoma patients. Thirty-nine patients (39 eyes) with primary open-angle glaucoma or normal-tension glaucoma underwent NPT. The results were compared with those in patients treated by penetrating trabeculectomy (PT) with MMC. In addition, the NPT patients were classified into two groups (group A, 24 patients treated between April 1998 and April 1999; group B, 21 patients treated from May 1999 onward), and the results were compared. The average intraocular pressure (IOP) was 12.6 +/- 2.8 mmHg with NPT and 12.4 +/- 3.0 mmHg with PT. No statistical differences between NPT and PT were identified with respect to IOP at any time after surgery. A life-table analysis showed that the probability of success (good IOP control) was 37.2% with NPT and 62.5% with PT. No significant difference was detected in postoperative IOP change or in the probability of success between NPT groups A and B. While postoperative IOP is similar between PT and NPT, the probability of success is better with PT than with NPT. Postoperative laser treatment after NPT is effective but sometimes has a negative influence on IOP control.

Evaluation of Changes in Peripapillary Nerve Fiber Layer Thickness after Deep Sclerectomy with Optical Coherence Tomography

To detect and quantify changes, using optical coherence tomography (OCT), in the peripapillary retinal nerve fiber layer (RNFL) thickness in patients with glaucoma who underwent deep sclerectomy. Prospective, controlled, interventional case series. Thirty-four consecutive patients who underwent monocular deep sclerectomy (surgery group) and medically treated fellow eyes (control group). Quantitative analysis of the peripapillary RNFL by OCT and automated perimetry were performed before surgery and 6 months after surgery in both eyes. The changes in RNFL thickness overall and by quadrant were evaluated and studied with respect to age, preoperative visual field test global indices, postoperative changes in intraocular pressure (IOP), and postoperative changes in visual field global indices. Changes observed in RNFL thickness were compared between eyes after surgery and in fellow eyes. The IOP decreased from a baseline mean of 23.6+/-5.1 mmHg to 11.7+/-2.9 mmHg (P<0.001) 6 months after surgery at the time of OCT testing. The mean percent IOP change was 48.4+/-15.7%. No significant changes in the mean RNFL thickness overall or by quadrant were observed after surgery or in the mean deviation (MD) and pattern standard deviation after surgery. There was no significant difference in the RNFL thickness between eyes in the surgery group and those in the control group. The mean preoperative visual field MD was significantly (P = 0.006) worse in eyes with a postoperative decrease in the overall RNFL thickness compared with those with an increase in the RNFL thickness. No correlation was found between RNFL thickness changes and age or changes in the visual field global indices. There was no significant difference between eyes with an IOP reduction of more than 50% and those with a reduction in IOP less than 30% (P = 0.514). The authors found no significant changes in the peripapillary RNFL thickness measured 6 months after deep sclerectomy. The only significant factor related to RNFL thickness changes after surgery was the preoperative visual field MD (P = 0.038).

Intraocular pressure decrease after phacoemulsification in patients with pseudoexfoliation syndrome

Purpose To determine the intraocular pressure (IOP) response to phacoemulsification cataract extraction with posterior chamber intraocular lens (PC IOL) implantation in patients with pseudoexfoliation syndrome. Setting Eye clinics at the University of Ottawa Eye Institute, Ottawa, Ontario, Canada. Methods A retrospective cohort study design assigned patients to 1 of 3 subgroups: pseudoexfoliation syndrome (PEX) (n = 21), primary open-angle glaucoma (POAG) control (n = 23), and cataract control (n = 23). Inclusion criteria consisted of age older than 50 years, open angle by gonioscopy, and a cataract requiring phacoemulsification. The IOP response was determined at intervals up to 18 months. Results Postoperative IOP changes from baseline in the PEX group were –1.81, –4.52, and –2.31 mm Hg at 3, 6, and 12 months, respectively. The changes in the POAG control group were –2.22, –2.32, and –1.88 mm Hg, respectively, and in the cataract control group, –2.49, +0.45, and +0.28 mm Hg. Patients in the PEX group had a reduction in IOP from baseline at all postoperative measurements. That reduction was significantly greater than in the POAG and cataract control groups at 6 months ( P = .012 and P = .002, respectively) and 12 months ( P = .001 and P = .050, respectively). Conclusions Patients with pseudoexfoliation syndrome had a postoperative IOP reduction from baseline at all measurements and a significantly greater reduction than patients in the POAG and cataract control groups at 6 and 12 months. Phacoemulsification cataract surgery with PC IOL implantation may be effective in managing patients with pseudoexfoliation syndrome who have elevated IOP and visually significant cataract but no advanced optic nerve damage.

Comparison of the effect of four viscoelastic agents on early postoperative intraocular pressure

Purpose: To compare the effect of four commercially available viscoelastic agents on postoperative intraocular pressure (IOP).Setting: Four outpatient sites.Methods: Sixty-nine patients having routine extracapsular cataract extraction were enrolled in the study; 54 were available for a 3 month follow-up examination. The four viscoelastic agents were Amvisc®, Amvisc® Plus, Healon®, and Viscoat®. Intraccular pressure was measured preoperatively and at 2, 3, 4, 5, 6, 8, 10, 12, and 24 hours and 3 months postoperatively. Pachymetry and endothelial cell counts were performed preoperatively and 3 months postoperatively.Results: Mean postoperative IOP and IOP changes from baseline did not differ among the four treatment groups at any time. However, when mean maximal IOP was compared, the Healon group demonstrated the highest IOP increases (P = .0033). There was also a significant difference (P = .0015) among treatment groups in the mean maximum postoperative change from baseline; the Healon group exhibited the largest mean change in IOP. At 3 months postoperatively, IOP values and pachymetry were normal for all treatment groups and were not statistically different among groups, indicating the four agents provided a similar degree of endothelial protection and IOP stability.Conclusion: These results suggest that IOP increases occur in varying degrees and at varying times in the early postoperative period after cataract surgery using a viscoelastic agent.

Intraocular Pressure Following Intravitreal Silicone Oil Injection

The clinical features of 100 consecutive cases and the histopathology of six enucleated eyes, all having undergone silicone oil injection for complicated retinal detachments, were studied with regard to the incidence and mechanisms of postoperative intraocular pressure changes. Preoperatively, five patients had glaucoma and 35 had hypotony (7 mm Hg or less). Immediately after surgery, 43 patients had glaucoma and 14 had hypotony, while seven had glaucoma and 39 had hypotony in the late postoperative period (average follow-up of 1 year). In most cases, the mechanism of intraocular pressure change did not appear to be directly related to the presence of silicone, but rather to the preoperative status of the eye and other aspects of the vitreoretinal surgery. When silicone was a factor, the resulting intraocular pressure appeared to represent a balance between mechanisms obstructing aqueous outflow (pupillary block and the reaction to silicone bubbles in the anterior chamber angle) and mechanisms reducing aqueous production (cyclitic membranes and retinal detachment).