Continued breakdown of the blood aqueous barrier following cataract surgery

Pseudophakic cystoid macular edema

PURPOSE OF REVIEW

Pseudophakic cystoid macular edema (PCME) is the most common postoperative complication of cataract surgery, resulting in visual decline. In this review, we discuss its pathophysiology, epidemiology, clinical presentation, and the current available evidence on therapeutic management.

RECENT FINDINGS

Patients with diabetes mellitus have twice the risk of developing PCME as compared to nondiabetic individuals. Recent large database studies have revealed an increased risk among young, male, and black patients. A previous history of PCME is perhaps the strongest risk factor for fellow eye involvement.

SUMMARY

PCME generally occurs around 6 weeks postoperatively and is likely a consequence of postoperative inflammation with disruption of the blood-queous and blood-retina barriers. Optical coherence tomography of the macula servers as a key diagnostic tool. There is a lack of large controlled clinical trials to guide treatment approaches. We recommend a stepwise approach for PCME that includes observation if not visually significant versus treatment with topical nonsteroidal anti-inflammatory drugs and steroids if symptomatic. Refractory cases can be treated with a periocular steroid injection, followed by intravitreal steroids if still nonresponsive.

Corneal Effect of Air Bubble After Phacoemulsification

Objectives

The aim of the study was to investigate the effect of air bubble on the cornea at the end of the cataract surgery with phacoemulsification.

Methods

This prospective and case-control study included 71 patients with air bubble injected into the anterior chamber at the end of the operation and 63 age-sex-matched control patients without air bubble. Endothelial cell density (ECD), coefficient of variation (CV), hexagonality rate (HEX), and central corneal thickness (CCT) measurements were taken using non-contact specular microscopy preoperatively and at 1-day, 1-week, and 1-month postoperatively.

Results

No significant difference was determined between the groups preoperatively in respect of mean visual acuity, anterior chamber depth, ECD, CV, HEX, and CCT values (p>0.05). The intraoperative average ultrasound power, effective phaco time, and ultrasound time values were similar (p>0.05). The CCT value was lower in the study group than in the control group on post-operative day 1 (p=0.012), but similar at 1 week and 1 month (p=0.102, p=0.330, respectively). No significant difference was determined between the groups in mean visual acuity, anterior chamber reaction, ECD, CV, and HEX values at 1-day, 1-week, and 1-month postoperatively (p>0.05).

Conclusion

Air bubble may be used as an alternative method to reduce corneal edema on the 1st post-operative day. According to the results, although air bubble has no detrimental effect, there is also seen to be no protective effect on the corneal endothelium.

Therapeutic effect of cataract surgery with simultaneous intravitreal injection of aflibercept on diabetic macular edema: An observational study

This study aimed to investigate the therapeutic effect of cataract surgery along with simultaneous intravitreal injection (IVI) of aflibercept on diabetic macular edema (DME). This cohort study enrolled 106 patients aged >40 years with type 2 diabetes mellitus and DME who received cataract surgery from January 1, 2016, to October 31, 2020. The baseline and mean data of the following parameters were collected: age, sex, glycated hemoglobin level, diabetic retinopathy (DR) grading, previous DR treatments including IVI of anti-vascular endothelial growth factor and pan-retinal photocoagulation, intraocular pressure, use of intraocular pressure-lowering medication, central subfield thickness (CST), and log MAR visual acuity (VA). Patients were categorized into 2 groups based on whether they received aflibercept IVI or not during cataract surgery and were compared using the t test and Fisher exact test for continuous and discrete variables, respectively. Beta coefficient and standard error were calculated using multiple linear regression analysis to identify the explanatory variables predictive of the net change of CST and log MAR VA. There was no difference in the net change in CST (15.24 ± 45.07 μm vs 18.62 ± 33.84 μm, P = .772) and log MAR VA (-0.27 ± 0.29 vs -0.37 ± 0.31, P = .215). Gender, glycated hemoglobin level, aflibercept IVI during cataract surgery, and baseline CST did not interfere with the morphological and functional outcomes of DME in cataract surgery. Older age was significantly and independently associated with a greater net change in log MAR VA. Proliferative DR was significantly and independently associated with a greater net change in CST and log MAR VA. A greater baseline log MAR VA was significantly and independently associated with lower net change in log MAR VA. Simultaneous aflibercept IVI for treating DME may not interfere with the functional and tomographic parameters of cataract surgery relative to cataract surgery alone. Factors influencing the outcomes of patients with DME undergoing cataract surgery are as follows: age, baseline DR staging, and baseline VA. Identifying these factors of DME preoperatively may be an important consideration in preventing it from progressing and for improving the overall visual prognosis.

Association of Cataract Surgery With Risk of Diabetic Retinopathy Among Asian Participants in the Singapore Epidemiology of Eye Diseases Study

IMPORTANCE

Cataracts and diabetic retinopathy (DR) are the leading causes of acquired blindness worldwide. Although extraction is the standard treatment option for cataracts, it is also reported to increase the risk of developing DR among individuals with diabetes. Nevertheless, the association between cataract surgery and risk of DR is still not well understood, and there have been no prior population-based reports in this area.

OBJECTIVE

To assess the risk of developing DR after cataract surgery among individuals with type 2 diabetes.

DESIGN, SETTING, AND PARTICIPANTS

A population-based prospective cohort study was conducted among participants recruited from the Singapore Epidemiology of Eye Diseases Study. The baseline visit was conducted between June 1, 2004, and March 31, 2009, and the 6-year follow-up visit was conducted between June 1, 2011, and July 31, 2016. Statistical analysis was performed from October 1 to 31, 2019.

EXPOSURES

Cataract surgery performed before a follow-up visit, determined based on slitlamp evaluation of lens status at baseline and follow-up visits.

MAIN OUTCOMES AND MEASURES

Eyes with incidence of DR were defined as those with the presence of any DR (level ≥15 based on the modified Airlie House classification system, graded from retinal photographs) at 6-year follow-up with no DR at baseline. The association between cataract surgery and incidence of DR was evaluated using a multivariable Poisson regression model with a generalized estimating equation to account for correlation between both eyes.

RESULTS

A total of 1734 eyes from 972 participants with diabetes (392 Malay individuals and 580 Indian individuals; 495 men; mean [SD] age, 58.7 [9.1] years) were included in the analysis. A total of 163 study eyes had already undergone cataract surgery at baseline, and a total of 187 eyes (originally phakic at baseline) underwent cataract surgery any time during the follow-up period. Of these 350 eyes, 77 (22.0%) developed DR. Among the 1384 eyes that never underwent cataract surgery, 195 (14.1%) developed DR. After adjustments for age, sex, race/ethnicity, baseline hemoglobin A1c level, duration of diabetes, random blood glucose level, antidiabetic medication use, hypertension, body mass index, and smoking status, multivariable regression analysis showed that any prior cataract surgery was associated with incidence of DR (relative risk, 1.70; 95% CI, 1.26-2.30; P = .001). Subgroup analyses by race/ethnicity showed similar associations in both Malay individuals (relative risk, 1.73; 95% CI, 1.13-2.69; P = .02) and Indian individuals (relative risk, 1.93; 95% CI, 1.33-2.80; P < .001).

CONCLUSIONS AND RELEVANCE

The findings of this population-based cohort study suggest that prior cataract surgery was associated with a higher risk of developing DR among individuals with diabetes. Further validation is warranted to confirm this association.

Silicone oil removal after extended tamponade in proliferative diabetic retinopathy-a long range of follow-up

BACKGROUND

To investigate the anatomical and functional results of silicone oil (SO) removal after an extended period of SO tamponade in eyes having received vitrectomy for proliferative diabetic retinopathy (PDR).

METHODS

From May 2009 to August 2017, clinical records of patients who had vitrectomy for PDR and underwent SO removal were retrospectively reviewed. SO was in principle left in the eye for an extended period of time and would be removed promptly when complications relevant to SO rose, or at the same setting when other intraocular surgeries were performed. Main outcome measures include anatomical outcome, functional outcome, and postoperative complications.

RESULTS

Seventy-four eyes of 64 patients (31 males and 33 females) were analysed. The mean follow-up duration was 35.6 months (ranging from 6 to 99 months, median 32 months). The duration of SO tamponade ranged from 3 to 116 months (mean 26.89 months, median 16 months). Anatomical success was achieved in 95.9% at the last follow-up with best-corrected visual acuity (BCVA) becoming better or unchanged in 81.1%. Postoperative complications included ocular hypertension (>25 mmHg; > 4 weeks) in three eyes (4.1%), macular hole in two eyes (2.7%), transient choroidal detachment in one eye (1.4%), vitreous haemorrhage in four eyes (5.4%) and hyphaema in two eyes (2.7%).

CONCLUSIONS

The rate of retinal redetachment after an extended period of SO tamponade and removal was low and the majority of eyes obtained final visual acuity improvement. SO removal after an extended period of tamponade in PDR seems to be safe under proper indications and case selection.

Outcomes in Patients with Diabetic Macular Edema Requiring Cataract Surgery in VISTA and VIVID Studies

PURPOSE

To evaluate the impact of cataract surgery on visual and anatomic outcomes in patients with diabetic macular edema treated with intravitreal aflibercept injection (IAI) or laser control and who did not require rescue therapy.

DESIGN

Post hoc analysis of 2 phase 3 trials, Study of Intravitreal Aflibercept Injection in Patients with Diabetic Macular Edema (VISTA) and Intravitreal Aflibercept Injection in Vision Impairment Due to DME (VIVID).

PARTICIPANTS

Fifty-four patients (laser treatment, n = 11; IAI, n = 43) who underwent cataract surgery during the study period.

METHODS

In VISTA and VIVID, patients received IAI 2 mg every 4 weeks, IAI 2 mg every 8 weeks after 5 monthly doses, or laser control through week 100. Starting at week 24, if rescue treatment criteria were met, IAI patients received laser therapy, and laser therapy patients received IAI 2 mg every 8 weeks (after 5 monthly doses). Patients who received rescue treatment before cataract surgery were excluded.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) in the laser control and pooled IAI groups before and after cataract surgery.

RESULTS

The cumulative incidence of cataract surgery did not depend on treatment group assignment (rate ratio, = 1.517; 95% confidence interval, 0.782-2.944; P = 0.2174). At the last study visit before surgery, BCVA was 62.2 and 56.9 letters and CRT was 342 μm and 301 μm in the laser control and IAI groups, respectively. At the first study visit after cataract surgery, BCVA was improved significantly in both the laser control and IAI groups to 73.5 letters (P = 0.010 compared with last visit before surgery) and 67.2 letters (P < 0.001 compared with last visit before surgery), respectively. Corresponding change in CRT was a modest increase to 364 μm (P > 0.05 compared with last visit before surgery) and 359 μm (P = 0.013 compared with last visit before surgery), respectively.

CONCLUSIONS

Incidence of cataract surgery was similar in both treatment groups. Despite a modest worsening in CRT after cataract surgery, BCVA was improved in both treatment groups.

Development of diabetic retinopathy after cataract surgery

This study explored whether cataract surgery precipitates diabetic retinopathy (DR) development in diabetic patients without previous DR. Patients with the diagnosis of type II diabetes but without DR were selected from the Longitudinal Health Insurance Database 2000. Patients who received cataract surgery between January 1, 2000, and December 31, 2010, were included in the case group, and the control group was matched to the case group by age, sex, and index year. The postoperative incidence rates of nonproliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), and diabetic macular edema (DME) were the main outcomes studied and were adjusted by age, sex, comorbidities, and statin, fibrate, angiotensin-converting-enzyme inhibitor (ACEI), oral hypoglycemic agents (OHA), and insulin use. In our cohort, patients who had dyslipidemia and used statins were more likely to undergo cataract surgery. Among diabetic patients without previous DR, patients receiving cataract surgery had a higher risk of NDPR development (adjusted hazard ratio = 1.48, 95% confidence interval = 1.15–1.91). No statistical difference was observed in PDR or DME development between operative and nonoperative groups. In additional stratified analyses, female sex, older age, comorbidities, surgery within 5 years, statin, ACEI, OHA, and insulin use increased the risk of NPDR development. In an adjusted Cox regression model, cataract surgery, OHA and insulin use were found to be risk factors for NPDR development. Cataract surgery with complications increased post-operative risks for NPDR were even higher, and the significant influence from cataract surgery persisted 5 years after surgery.

Factors Predisposing to Postoperative Intraocular Inflammation

This prospective study of 123 patients undergoing cataract extraction determined the preoperative and surgical factors predisposing to an exaggerated postoperative inflammatory response. It is important to identify the patients at increased risk of complications requiring additional prophylaxis or more intensive postoperative care, particularly when selecting patients for day case surgery. Previous intraocular inflammation or surgery was the factor most strongly associated with marked inflammation on the first postoperative day (p < 0.01, compared to uncomplicated patients). As a result, patients stayed in hospital an average of one day longer (p < 0.001) and required significantly more steroid drops (p < 0.001). Other factors of significance, but reducing importance were: difficult surgery, non-caucasian race and brown irides. Amongst uncomplicated patients, the difficulty of surgery was most significantly related to a high inflammation score (p < 0.01). Non-caucasian patients stayed in hospital significantly longer than their caucasian counterparts (p < 0.05), and required more steroid drops (p < 0.001). Of caucasian patients, those with brown irides were inpatients for significantly longer than those with blue or hazel (p < 0.05). No other factors studied significantly altered postoperative inflammation: neither the presence of diabetes, nor the technique of cataract extraction.

Efficacy of nepafenac ophthalmic suspension 0.1% in improving clinical outcomes following cataract surgery in patients with diabetes: an analysis of two randomized studies

OBJECTIVE

To assess the efficacy of nepafenac 0.1% ophthalmic suspension in improving the clinical outcomes following cataract surgery (CS) in patients with nonproliferative diabetic retinopathy.

METHODS

In two similar multicenter, randomized studies, patients received either nepafenac 0.1% or vehicle, instilled three times daily starting a day prior to surgery and continuing for 90 days postoperatively. A post hoc analysis of these two studies was conducted to assess 1) the likelihood for development of postoperative macular edema (ME), based on the percentage of patients who developed ME (≥30% increase from preoperative baseline in central subfield macular thickness) within 90 days following CS and 2) best-corrected visual acuity (BCVA) endpoints, including the percentage of patients with a BCVA improvement of ≥15 letters from preoperative baseline to Day 14 and maintained through Day 90. Results for individual studies and their pooled estimates (only visual acuity endpoints) are reported. Primary inference was based on odds ratio (OR).

RESULTS

This post hoc analysis included 411 patients (nepafenac 0.1%: 205; vehicle: 206). The incidence of postoperative ME within 90 days of CS was notably lower in the nepafenac-treated patients than in vehicle-treated patients (study 1: 3.2% vs 16.7%; OR =0.2, 95% confidence interval [CI] =0.1, 0.5, P=0.001; study 2: 5.0% vs 17.5%; OR =0.2, 95% CI =0.1, 0.8, P=0.018). A higher percentage of nepafenac-treated patients than vehicle-treated patients gained ≥15 letters from preoperative baseline to Day 14, which was maintained through Day 90 (study 1: 38.4% vs 21.4%; OR =2.4, 95% CI =1.4, 4.2, P=0.003; study 2: 35.0% vs 25.0%; OR =1.6, 95% CI =0.8, 3.2, P=0.172; pooled: 37.1% vs 22.8%; OR =2.0, 95% CI =1.3, 3.1, P=0.001). The odds of >5-letter and >10-letter loss in BCVA from postoperative Day 7 were higher in vehicle-treated than in nepafenac-treated patients.

CONCLUSION

These results support the clinical benefit of prophylactic use of nepafenac 0.1% for reducing the risk of postoperative ME and for improvement in BCVA outcomes following CS in patients with nonproliferative diabetic retinopathy.

Long-Term Outcomes of Primary Trabeculectomy in Diabetic Patients without Retinopathy with Primary Angle-Closure Glaucoma

Purpose. To evaluate primary trabeculectomy with adjunctive mitomycin-C (MMC) in diabetic patients without retinopathy with primary angle-closure glaucoma (PACG). Design. This is a retrospective case series comparison. Participants. This retrospective trial compared outcomes of 88 eyes that underwent trabeculectomy in patients with diabetes mellitus (DM) without retinopathy and in 97 patients without DM. Methods. In this study, the intraocular pressure (IOP), visual acuity, visual field, and postoperative complications were compared between the two groups. Qualified surgical success is defined as an IOP between 6 and 18 mmHg with or without topical antiglaucoma medication. Results. After a follow-up of 5 years, the IOP decreased from a mean basal IOP of 27.8 ± 7.3 mmHg to 15.0 ± 5.6 mmHg in the DM group and from 27.3 ± 6.0 mmHg to 12.4 ± 5.3 mmHg in the control group. The mean number of antiglaucoma medications was 3.4 ± 1.3 and 3.3 ± 1.2 preoperatively (P = 0.587) whereas it was 1.7 ± 1.5 and 1.1 ± 1.4 at the 5-year follow-up (P = 0.049). The 5-year qualified surgical success rates were 42.9% and 65.4% for both groups (P = 0.046; log-rank test). Encysted blebs were seen in 21 (23.9%) patients in the DM group and in 12 (12.4%) patients in the control group (P = 0.041). Conclusion. PACG patients with DM without retinopathy undergoing primary trabeculectomy with MMC may have a lower long-term surgical survival rate compared with patients without DM.

Effects of vitrectomy on age-related macular degeneration

PURPOSE

To determine whether vitrectomy alters the long-term progression of age-related macular degeneration (AMD).

DESIGN

Retrospective case-control study.

PARTICIPANTS

Forty-four eyes of 22 patients with AMD who underwent vitrectomy in 1 eye were included in the study. The progression of AMD at follow-up in the 22 eyes that underwent vitrectomy was compared with the 22 fellow, nonvitrectomized eyes.

METHODS

The charts and photographs of subjects with Age-Related Eye Disease Study category 3 AMD in both eyes who previously underwent vitrectomy surgery for an epiretinal membrane or macular hole were reviewed. Subjects were excluded if they had had a vitrectomy in both eyes, had <2 years of follow-up, had previous choroidal neovascularization (CNV), retinal detachment, diabetic retinopathy, angioid streaks, high myopia, vascular occlusions, or extensive macular scarring in either eye, or insufficient hospital records or photographs to determine the extent of AMD. Clinical notes throughout the follow-up interval were reviewed. Two vitreoretinal specialists independently graded pre- and postvitrectomy fundus photographs of all eyes in a masked fashion.

MAIN OUTCOME MEASURES

The development or progression of geographic atrophy of the retinal pigment epithelium and the development of CNV.

RESULTS

Twenty-two patients were included. The average follow up interval was 5.5 years (range, 2-15). Choroidal neovascularization developed in 5 control eyes and in 2 vitrectomized eyes, and atrophy developed in 7 control and 4 vitrectomized eyes. The difference between vitrectomized eyes and fellow eyes for the combined end points of RPE geographic atrophy or CNV was significant (P = 0.02).

CONCLUSIONS

In this pilot study, we did not detect that vitrectomy increased the progression of AMD. In fact, it was associated with a reduced progression to geographic atrophy or CNV. Additional studies are needed to confirm or refute this association.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Osseous metaplasia in the eye of a dog

Incisional iris biopsy was performed for diagnosis of an unusual opaque white mass protruding from the right ventrolateral iris of a 10-year-old neutered male Great Dane dog. Histopathology revealed a diagnosis of bone formation within otherwise normal iris tissue. No underlying etiology was identified. Osseous metaplasia or heterotopic bone formation may be an additional differential diagnosis for a nonneoplastic mass in the eye of a dog.

Mouse model of post-surgical breakdown of the blood-retinal barrier

PURPOSE

Post-surgical macular edema is an important clinical problem resulting from breakdown of the blood-retinal barrier (BRB) after surgery. This study was designed to develop a mouse model of post-surgical BRB breakdown.

METHODS

Two 25-gauge needles, one for infusion and one for aspiration, were inserted through the limbus and into the lens of one eye of adult male C57BL/6 mice. The anterior portion of the lens was aspirated and the fellow eye was untreated. At several time points after surgery, the integrity of the BRB was assessed quantitatively, using [3H]mannitol as a tracer, or qualitatively, using immunohistochemical staining for albumin.

RESULTS

Eyes with partial lens extraction had a significant increase in retinal vascular leakage one day after surgery, which persisted two and three days after surgery, but by five days, was not significantly different from controls. Immunohistochemical staining for albumin demonstrated that the breech in the barrier was sufficient to allow passage of a 60kDa protein into the retina, and was localized predominantly to retinal vessels.

CONCLUSIONS

Partial lens extraction in mice results in BRB breakdown (primarily the inner BRB) that is highly reproducible in the severity of leakage and its time course. This provides a valuable tool for investigation of the molecular pathogenesis and new treatment approaches for post-surgical breakdown of the BRB.

Cataract surgery and diabetic retinopathy

Diabetes is a risk factor for the development of cataracts. Studies have shown an increased risk of ocular complications in diabetics after cataract surgery, but modern surgical techniques have minimized them, leading to an overall good visual outcome. Macular edema before surgery is the most common condition that limits post-operative visual recovery. Thus, pre-operative laser treatment is needed. Photocoagulation of preproliferative or early proliferative diabetic retinopathy is also advisable, due to the increased risk of iris neovascularization or retinopathy progression after surgery.

Therapeutic application of tissue plasminogen activator for fibrin reaction after cataract surgery

PURPOSE

To evaluate the efficacy and safety of therapeutic application of recombinant tissue plasminogen activator (rtPA) for fibrin reaction after uneventful cataract surgery.

SETTING

Department of Ophthalmology, SSK Istanbul Hospital, Istanbul, Turkey.

METHOD

In a prospective study between January and June 2000, 26 eyes of 26 patients with fibrin reaction after uneventful cataract surgery received 3 microg of intracameral rtPA. Patients were evaluated for recurrences of fibrin reaction or complications by slitlamp biomicroscopy 2, 12, and 24 hours, 1 week, and 1 and 6 months after rtPA application. Intraocular pressure (IOP) was measured by Goldmann applanation tonometry. Visual acuity was tested using a standard Snellen chart 1 week after rtPA application.

RESULTS

All 26 eyes had complete fibrinolysis. Three eyes (11.5%) had corneal edema that lasted fewer than 24 hours. Visual acuity improved by 0 to 7 lines in 19 patients (73.1%). No patient had an increase in IOP. At 6 months, no patient had hyphema or recurrence of fibrin reaction.

CONCLUSIONS

Complete lysis of fibrin after cataract surgery with conventional topical medications can take a long time and is not successful in some patients. Intracameral application of 3 microg rtPA was an efficient, safe method for the treatment of fibrin reaction after cataract surgery.

Prediction of macular edema exacerbation after phacoemulsification in patients with nonproliferative diabetic retinopathy

PURPOSE

To ascertain whether the aqueous humor levels of vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), and protein can predict the postoperative exacerbation of macular edema in patients with nonproliferative diabetic retinopathy (NPDR) after phacoemulsification surgery for cataract.

SETTING

Department of Ophthalmology, Diabetes Center, Tokyo Women's Medical University, Tokyo, Japan.

METHODS

This prospective study included 104 consecutive patients (104 eyes) with NPDR who had cataract surgery. The concentrations of VEGF and IL-6 in aqueous humor specimens obtained during cataract surgery were measured by enzyme-linked immunosorbent assay. Patients were followed for 6 months to assess the postoperative exacerbation of macular edema.

RESULTS

Ninety patients (87%) achieved a visual acuity of 20/40 or better. Exacerbation of macular edema was seen in 30 eyes (29%) after 6 months. Hypertension and the aqueous levels of VEGF, IL-6, and protein were significantly correlated with the exacerbation of macular edema (odds ratio 1.16, 1.33, 1.27, and 1.28, respectively). In contrast, there was no correlation between the exacerbation of macular edema and other systemic factors. Multivariate logistic regression analysis showed that the aqueous VEGF level increase of 100 pg/mL increased the macular edema after phacoemulsification surgery (odds ratio 1.53).

CONCLUSIONS

A high VEGF level in the aqueous humor predicted a significant risk for the postoperative exacerbation of macular edema. A model was developed to predict the risk exacerbation.

Phacoemulsification versus extracapsular cataract extraction in patients with diabetes

OBJECTIVE

To compare phacoemulsification with extracapsular cataract surgery in patients with diabetes and to identify determinants of postoperative visual acuity.

DESIGN

Prospective, randomized, paired-eye trial.

PARTICIPANTS

Forty-six patients with diabetes and bilateral cataract.

INTERVENTION

Patients were allocated to phacoemulsification surgery with silicone intraocular lens to one randomly determined eye, and extracapsular cataract surgery with 7-mm polymethylmethacrylate intraocular lens to the other.

MAIN OUTCOME MEASURES

Logarithm of minimum angle of resolution visual acuity (logMAR VA), incidence of clinically significant macular edema (CSME), retinopathy progression, indices of anterior segment inflammation, and incidence of capsulotomy.

RESULTS

Compared with eyes undergoing phacoemulsification, eyes managed with extracapsular surgery had more anterior chamber cells (P = 0.0004) and flare (P = 0.007) 1 week after surgery and a higher incidence of posterior synechiae (P = 0.04) and intraocular lens deposits (P < 0.0005) in the first postoperative year. The need for posterior capsulotomy was greater in eyes undergoing extracapsular surgery (16 of 46 vs. 5 of 46, P = 0.01). No difference in incidence of postoperative CSME, progression of retinopathy, or development of high-risk proliferative retinopathy was identified between techniques (P = 1.0, 0.8, and 0.2). Median 1-year logMAR VA was worse in eyes undergoing extracapsular surgery (0.08 vs. 0.06, P = 0.02), especially in those with retinopathy (0.14 vs. 0.08, respectively; P = 0.01). The presence or absence of CSME at the time of surgery was the most significant determinant of 1-year logMAR VA in regression models for both extracapsular (P = 0.0004, R2 = 0.45) and phacoemulsification groups (P < 0.00005, R2 = 0.46).

CONCLUSIONS

Phacoemulsification is associated with better postoperative VA, less postoperative inflammation, and less need for capsulotomy than extracapsular cataract surgery in patients with diabetes. However, with both techniques, the principal determinant of postoperative VA appears to be the presence or absence of CSME at the time of surgery. Early intervention, reducing the risk that unrecognized CSME is present at the time of surgery, may be more critical to outcome than choice of surgical technique.

Long-term disorders of the blood-aqueous barrier after small-incision cataract surgery

PURPOSE

To determine the long-term function of the blood-aqueous barrier after small-incision cataract surgery with implantation of a foldable intraocular lens.

METHODS

The blood-aqueous barrier function in 74 eyes of 62 patients who underwent cataract surgery was examined using a laser flare-cell meter. The measurements were performed pre-operatively and post-operatively between 12 and 35 months after surgery. For statistical analysis a linear regression was used. The study was designed as a single cohort study, with comparison of pre- and post-operative values.

RESULTS

Highly statistically significant differences (p < 0.0001) were found between pre-operative flare values and those measured at the final visit. The linear regression model showed significantly higher flare values post-operatively compared with those measured pre-operatively. Other variables such as incision technique, sex, operation time, phaco time and systemic disease had no influence on this outcome.

CONCLUSION

The results suggest that there is persistent blood-aqueous barrier dysregulation even several years after cataract surgery.

Trabeculectomy function after cataract extraction

OBJECTIVE

To examine the effect of cataract extraction (CE) after trabeculectomy on intraocular pressure (IOP) control.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

A total of 115 consecutive patients who underwent extracapsular CE (N = 58) or phacoemulsification (N = 57) with intraocular lens (IOL) placement after trabeculectomy were studied.

INTERVENTION

Cataract extraction with IOL after trabeculectomy was performed.

MAIN OUTCOME MEASURES

Preoperative, intraoperative, and postoperative factors were evaluated for association with loss of IOP control requiring additional medications, bleb needling, or further glaucoma surgery, using Kaplan-Meier survival analysis and Cox multivariate proportional hazards survival regression.

RESULTS

After mean postoperative follow-up of 21.1 +/- 14.3 months, additional glaucoma medication or needling of the filtering bleb to maintain IOP control was required in 35 eyes (30.4%) and was significantly associated with intraoperative iris manipulation and early postoperative peak IOP greater than 25 mmHg. Additional glaucoma surgery was eventually required in 11 eyes (9.6%) and was significantly associated with age of 50 years or younger, preoperative IOP greater than 10 mmHg, and early postoperative peak IOP greater than 25 mmHg. The cumulative proportion of patients who did not require reoperation for glaucoma was 93% and 90% at 1 and 2 years, respectively. The mean IOP at last visit had increased 1.6 mmHg above the pre-CE level and did not vary significantly after the first postoperative month. The median interval from CE to the addition of glaucoma medication or bleb needling was 1.6 months (within 3 months in 20 of 33 eyes) and that from nonsurgical intervention to further glaucoma surgery was 3.6 months (before the 7th postoperative month in 6 of 11 eyes). Of 19 eyes with hypotony (IOP < or = 6 mmHg) before CE, 11 eyes remained hypotonous after CE despite an increase in the mean IOP from 4.6 to 7.5 mmHg.

CONCLUSIONS

When CE is performed after trabeculectomy, age of 50 years or younger, preoperative IOP greater than 10 mmHg, intraoperative iris manipulation, and early postoperative IOP greater than 25 mmHg are associated with worsened postoperative IOP control. Most bleb failures occur soon after CE. Resolution of pre-existing hypotony after CE is unpredictable.

Aqueous flare intensity after phacoemulsification in patients with diabetes mellitus

PURPOSE

To prospectively compare the postoperative blood-aqueous barrier breakdown induced by phacoemulsification and implantation of a heparin-surface-modified poly(methyl methacrylate) intraocular lens in the capsular bag in eyes with different stages of diabetic retinopathy (DR) and a control group.

SETTING

St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden.

METHODS

Aqueous flare intensity was measured preoperatively and 1 day, 1 week, and 3 months postoperatively in 21 nondiabetic control patients (Group 1), 20 diabetic patients with no or mild-moderate nonproliferative DR (Group 2), and 19 diabetic patients with advanced DR (moderate-severe, severe nonproliferative, and proliferative DR) who were divided into groups: without clinically significant macular edema (CSME), 7 eyes (Group 3), and with CSME, 12 eyes (Group 4).

RESULTS

Before surgery, flare intensity in Group 4 was significantly higher than in Groups 1 and 2 (P < .05). Surgical trauma increased flare values 1 day postoperatively in all groups. One week after surgery, Groups 1 and 4 had flare intensity significantly higher than preoperatively (P < .05). Recovery of flare occurred 3 months postoperatively in all groups except Group 2, in which it occurred 1 week after surgery. One day postoperatively, only Group 4 had significantly higher flare than Group 1 (P < .05). One week and 3 months after surgery, Group 4 had significantly higher flare intensity than Groups 1 and 2 (P < .05). The duration of phacoemulsification in Groups 2 and 4 was significantly longer than in Group 1 (P < .05). Operating time was significantly longer than in Group 1 only in Group 4 (P < .05).

CONCLUSION

Eyes with advanced stages of DR and with CSME had the highest flare intensity after cataract surgery.

Biocompatibility and blood-aqueous barrier impairment in at-risk eyes with heparin-surface-modified or unmodified lenses

PURPOSE

To evaluated the influence of heparin-surface-modified (HSM) versus unmodified poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) on the blood-aqueous barrier (BAB) in at-risk eyes.

SETTING

Department of Ophthalmology, Bundesknappschaft's Hospital, Sulzbach Germany.

METHODS

This study comprised 100 patients with predisposing risk factors for BAB destabilization (e.g., diabetes mellitus with or without retinopathy, glaucoma, pseudoexfoliation, uveitis). One eye in each patient received an HSM IOL and the fellow eye, a conventional unmodified PMMA IOL after phacoemulsification by the same surgeon. Anterior chamber flare was measured with the Kowa 500 laser flare meter 1 day before and 1 day, 1 and 6 weeks, and 3 months after surgery.

RESULTS

For most risk factors, mean flare was lower in the HSM group than in the PMMA group at most follow-ups. Significantly lower flare values (difference between postoperative and preoperative mean values) were seen in eyes with the HSM IOL at 6 weeks (P < .004) and 3 months (P < .003; Student's t-test). In the group with preoperative elevated flare values, the eyes with the HSM IOL had significantly better results 6 weeks (P < .0006) and 3 months (P < .01) postoperatively. The values in the HSM IOL eyes were also significantly higher in the diabetic with retinopathy group at 3 months (P < .003).

CONCLUSION

The results confirm the efficacy of IOL surface modification in reducing postoperative intraocular reaction in at-risk eyes.

Intraocular lens complications requiring removal or exchange

Intraocular lens (IOL)-related complications are caused primarily by mechanical trauma, inflammatory or infectious complications, or optical problems. Complications may occur at the time of surgery or be the result of an ongoing postoperative process. Mechanical and inflammatory injury may produce corneal decompensation, cystoid macular edema, hyphema, uveitis, and glaucoma, causing reduced vision and in some cases chronic pain. Optical problems may be due to a wrong power of the IOL or to postoperative decentration or dislocation of the lens. Ophthalmologists should be aware of the indications for IOL removal or exchange in those patients who have ongoing IOL-induced injury or impairment. Removal or exchange of an IOL frequently involves a complex decision-making process and is often associated with immense technical challenge. Various medical and surgical treatments may be tried to correct IOL problems before the decision is made to remove or exchange the lens.

The effect of heparin-coated intraocular lenses on intraocular pressure following combined trabeculectomy and cataract surgery

PURPOSE

To review the effects on intraocular pressure control of the use of standard and heparin-coated intraocular lenses (IOLs) following combined cataract and glaucoma surgery after a minimum period of 2 years.

METHODS

Case note review of all patients with glaucoma who required cataract extraction combined with trabeculectomy and who were randomized to either of the two IOL types. The number of ocular hypotensive medications and the intraocular pressures were recorded pre-operatively and at 3, 6, 18 and 24 months following surgery.

RESULTS

The two groups (9 receiving standard IOLs and 10 heparin-coated IOLs) were comparable for age, sex and follow-up, as were the pre-operative intraocular pressures and number of treatments. Post-operatively, all patients achieved an intraocular pressure < 21 mmHg at the final visit, with only one patient in each group requiring topical medication, but the standard lens group had a higher intraocular pressure at 2 years (p<0.05). The magnitude of the fall from the pre-operative values was greater in the heparin-coated lens group at 2 years after surgery (p<0.02). The presence of a visible drainage bleb occurred equally frequently in the two groups.

CONCLUSIONS

Use of a heparin-coated IOL does not adversely affect the intraocular pressure control following combined cataract and drainage surgery. The greater fall in intraocular pressure at 2 years in those receiving a heparin-coated IOL may have occurred by chance.

Relation between postoperative blood-aqueous barrier damage and LOCS III cataract gradings following routine phacoemulsification surgery

AIM

To examine the relation between cataract density, the phacoemulsification energy required for its removal, and blood-aqueous barrier (BAB) damage on the first day after surgery.

METHODS

A prospective study recruiting patients with normal eyes apart from senile cataract. Preoperatively, visual acuity, anterior chamber laser flare, and cell values were measured using the Kowa laser flare meter, and the LOCS III grading of the cataract defined. The patients all underwent standardised phacoemulsification surgery through a superior scleral tunnel incision, with confirmed in the bag placement of a one piece PMMA IOL; all surgical complications were excluded. The phaco power delivered was recorded as the cumulative delivered energy, CDE. On day 1 visual acuity and laser flare and cell readings were taken.

RESULTS

101 patients were recruited and all completed the protocol. Older patients had a higher preoperative flare value (p = 0.003); preoperative cell values were significantly related to nuclear opacity (p = 0.021) and colour (p = 0.011). Postoperative flare was related to preoperative flare (p = 0.001) and nuclear colour (p = 0.038). CDE was related to nuclear colour (p = 0.031) and opacity (p = 0.022), but not to aqueous flare.

CONCLUSIONS

Damage to BAB after routine phacoemulsification surgery is predicted by the preoperative flare values and the density of the cataract nucleus. The amount of phacoemulsification energy required to remove a cataractous lens is related to the density of the cataract but affects postoperative flare to a minimal degree. Other factors such as surgical technique are probably more important. Laser photometry is a useful tool for objectively assessing surgical technique.

Diffusion coefficient through the blood-aqueous barrier using a standard protocol

AIMS/BACKGROUND

Comparison of the diffusion coefficient through the blood-aqueous barrier of healthy volunteers measured in different cities with identical fluorophotometers using a standardised protocol.

METHODS

Healthy volunteers aged between 20 and 70 years were studied in seven European cities. The fluorescein concentration in the anterior segment of each eye was measured with a commercial scanning fluorophotometer 30 and 40 minutes after intravenous fluorescein. The decay of non-protein bound fluorescein concentration in blood plasma was determined with the use of three blood samples taken at 7, 15, and 55 minutes after injection. The diffusion coefficient through the blood-aqueous barrier was calculated from the ratio between the fluorescein concentration in the anterior chamber and the time integral of non-protein bound fluorescein concentration in plasma using specially developed software.

RESULTS

The mean values of the diffusion coefficient (SD) (X10(-4) min-1) were 4.76 (1.51) (n = 20, Brussels), 5.48 (2.33) (n = 17, Coimbra), 3.47 (2.09) (n = 12, Cologne), 6.09 (2.77) (n = 21, Frankfurt), 3.85 (1.59) (n = 11, Ghent), 4.99 (1.69) (n = 23, Leiden), and 4.87 (1.05) (n = 20, Madrid). The values between centres were similar (Kruskal-Wallis test p > 0.05) except for Cologne and Frankfurt (p = 0.013). No differences were found when repeating measurements (four centres, interval time 1-8 months, Wilcoxon paired test p > 0.39).

CONCLUSION

The diffusion coefficients had similar values and standard deviations. The concerted action demonstrated the usefulness of a standardised protocol.

Visual acuity following extracapsular cataract extraction in diabetes: a meta-analysis

Although pre-operative retinopathy severity appears to be a major factor in determining the visual outcome of diabetic extracapsular cataract extraction, its precise relationship to post-operative visual acuity is ill defined. A meta-analysis was therefore carried out, and studies were included if pre-operative maculopathy and retinopathy status was sufficiently defined to permit discrimination of visual outcome between subgroups. Weighted mean proportions of eyes achieving a post-operative visual acuity > or = 6/12 were as follows: no retinopathy, 87%; non-proliferative retinopathy with no maculopathy, 80%; quiescent proliferative retinopathy with no maculopathy, 57%; non-proliferative retinopathy with maculopathy, 41%; quiescent proliferative retinopathy with maculopathy, 11%; active proliferative retinopathy, 0. Differences in visual outcome between groups were significant (chi 2 = 119.9, p < 0.0005), attributable mostly to the trend across groups (chi 2 for trend = 115.4, p < 0.0005). Logistic regression indicated that maculopathy was a more potent predictor of post-operative visual acuity < or = 6/12 (odds ratio 6.4, 95% CI 4.13-9.94, p < 0.0005) than quiescent proliferative retinopathy (odds ratio 3.33, 95% CI 2.04-5.42, p < 0.0005). The severity of retinopathy and maculopathy prior to cataract surgery in diabetics are the major determinants of post-operative visual acuity. Further study of the relationship between pre-operative retinopathy severity and the incidence of post-operative complications, progression of retinopathy and maculopathy is required to optimise the management of cataract in diabetes.

Mechanism of iris prolapse: a qualitative analysis and implications for surgical technique

A theoretical explanation of the mechanism of iris prolapse is presented using simple flow mechanics and the Bernouille principle, which states that fluid pressure varies inversely to fluid velocity. Rapid aqueous escape into an anterior chamber perforation thus creates a relative vacuum anterior to the iris. Further analysis shows that the tendency of the iris to prolapse into an anterior chamber wound increases as an inverse function of the fourth power of the radial distance between the iris and the perforation. Anterior wound placement, clear of the iris plane, should help to prevent iris prolapse. Minimizing the irrigation velocity (and hence the fluid outflow velocity) should also help to prevent intraoperative prolapse.

Effects of subconjunctival methylprednisolone on the blood aqueous barrier following cataract surgery

The aim of this double-blind randomized study was to assess the effect of subconjunctival methylprednisolone hemisuccinate (MH) on the recovery of the blood aqueous barrier (BAB) following uncomplicated cataract surgery performed by the same surgeon in normal eyes. Fifty eyes of fifty patients (28 female, 22 male, mean age 72.3 +/- 11.2 years) were randomized into two groups: group 1 received a subconjunctival injection of MH (40 mg in 0.5 cc) at the end of the surgery and group 2 did not. All patients were free of other ocular or systemic diseases known to alter the BAB and were not taking any anti-inflammatory medications. Postoperative treatments were similar in both groups. The patients were submitted to laser flare photometry 30 minutes to one hour after mydriasis with a drop of tropicamide preoperatively and on the first, second and seventh day and then one month and six months following surgery. No difference in aqueous flare was seen between the two groups on any of postoperative visits. These data suggest that subconjunctival MH has no beneficial effect in postoperative BAB permeability following uncomplicated cataract surgery in normal eyes.

Pattern of characteristics in cataract patients

Cataract extraction was performed in 1261 eyes. The relevant information was complete in 826 cases and thus only these were included in this study. Eleven variables describing clinical history, preoperative findings, operative problems and one variable representing visual acuity 4 months postoperatively were entered into a factor analysis model. Three factors were extracted by factor analysis, and these factors may be considered to be the underlying causes embracing the individual variables. Factor 1: the maculopathy factor; explained 23.3% of the total variance. Sixteen percent of the variance was attributable to Factor 2: the miosis factor. Lastly, Factor 3: operative problems; was responsible for 13.4% of the variance. The maculopathy factor was significantly associated with postoperative visual acuity (p < 0.001). Slight significant association was also found between the factor for operative problems and visual outcome, whereas no association was seen between the miosis factor and the final vision.

Trabeculectomy in diabetic patients with glaucoma

Forty-one eyes of 41 patients with diabetes mellitus who underwent trabeculectomy over a 4-year period were compared with 41 age- and sex-matched controls, who were also matched for date of operation and surgical technique. The two groups were comparable for glaucoma diagnoses, duration of glaucoma before admission and number of ocular hypotensive medications. The intraocular pressures at diagnosis and on admission were similar. Post-operative complications were equally frequent. The mean intraocular pressure at 6 months was significantly lower in the control group, and fewer diabetic patients achieved either an intraocular pressure < 21 mmHg or successful drainage (defined as an intraocular pressure < 21 mmHg on no treatment) at 6 months and at the final visit, after similar periods of follow-up. Trabeculectomy in diabetic patients with pre-existing retinopathy resulted in a significantly higher intraocular pressure at 6 months than when no retinopathy was present.

Anterior hyaloidal fibrovascular proliferation after extracapsular cataract extraction in diabetic eyes

Four patients with proliferative diabetic retinopathy developed anterior hyaloidal fibrovascular proliferation after extracapsular cataract extraction and posterior chamber lens implantation. This complication of cataract extraction has been described after vitrectomy in diabetic eyes. Risk factors for this entity after extracapsular cataract extraction include proliferative diabetic retinopathy, iris neovascularization, and anterior ischemic retina. Anterior hyaloidal fibrovascular proliferation was observed an average of 12 months postoperatively and affected vision in one of four patients. No progression was seen within an average of six months of follow-up, and no complications such as traction retinal detachment and vitreous hemorrhage developed.

The effects of subconjunctival betamethasone on the blood aqueous barrier following cataract surgery: a double-blind randomised prospective study

The aim of this double-blind randomised prospective study was to assess the effect of subconjunctival Betnesol (betamethasone sodium phosphate 0.1%) on the recovery of the blood aqueous barrier (BAB) following cataract surgery in uncomplicated eyes. Twenty patients [10 male, mean age 71.4 (SD 12.7) years] admitted for routine cataract surgery were randomised into two groups. All patients recruited into the study were free of other ocular disease and were not taking any anti-inflammatory medication. Group A received a subconjunctival injection of cefuroxime (125 mg) alone while group B received a subconjunctival injection of both cefuroxime and Betnesol. All surgery was performed by a single surgeon using a standardised surgical technique and all patients received the same postoperative medication. The Kowa laser flare cell meter was used to measure aqueous flare and cells preoperatively and on the first, second, and seventh postoperative day, and at 1 and 3 months following surgery. The code was broken only after all patients had been followed-up for 3 months postoperatively. There was no significant difference between the two groups in aqueous flare and cells at any of the postoperative visits. In this study we were unable to demonstrate any beneficial effect of subconjunctival betamethasone on damage to and recovery of the BAB following cataract surgery in the uncomplicated eye.