Recombinant tissue plasminogen activator following paediatric cataract surgery

Use of Intracameral Tissue Plasminogen Activator During Uveitic Cataract Surgery

PURPOSE

To report the outcomes of intracameral tissue plasminogen activator (tPA) use during uveitic cataract surgery.

DESIGN

Retrospective case series from a single United States tertiary center of 36 eyes from 31 consecutive patients with established uveitis who received intraoperative intracameral tPA during cataract surgery between 2016 and 2020.

RESULTS

Mean visual acuity (VA) improved from logMAR 1.0 ± 0.7 preoperatively to logMAR 0.7 ± 0.8 by POM12. VA improved from baseline postoperatively (POM1 p = 0.0002, POM6 p = 0.006 and POM12 p = 0.007). Minimal to no anterior chamber inflammation was achieved in 47.2% of the eyes by POW1 and 80.0% of the eyes by POM1. Mean clock-hours of posterior synechiae improved from 8.2 ± 3.8 preoperatively to 0.1 ± 0.6 by POM12. Six eyes developed hyphema and/or vitreous hemorrhage, four of which resolved spontaneously.

CONCLUSIONS

Adjunctive intracameral tPA during uveitic cataract surgery improves VA and intraocular inflammation, but risks postoperative hemorrhage. Intraoperative tPA as adjunctive anti-inflammatory therapy warrants randomized prospective studies.

Double trouble in DMEK surgery: Learning experience and review of the literature

PURPOSE

To report a challenging Descemet Membrane Endothelial Keratoplasty (DMEK) case, complicated by intraoperative aqueous misdirection and spontaneous anterior chamber fibrin reaction.

METHODS

A 70-year-old female affected by corneal edema due to Fuchs endothelial dystrophy underwent a triple procedure (cataract extraction - IOL implantation - DMEK surgery) in her left eye. This report illustrates the management of the intraoperative complications of aqueous misdirection syndrome and anterior chamber fibrin reaction.

RESULTS

Despite the optimal management of the posterior pressure and the thorough removal of the fibrinous reaction during the case, the DMEK graft was not completely unfolded and centred at the end of the surgical procedure. Nonetheless, the patient showed good long-term anatomical and functional recovery: at the last follow-up (2 years after surgery), central corneal thickness was 526 µm with a best corrected visual acuity of 20/25 and an endothelial cell density of 1112 cell/mm2.

CONCLUSION

Early recognition and prompt management of intraoperative aqueous misdirection syndrome and anterior chamber fibrin reaction during DMEK surgery is essential to ensure good functional and anatomical outcomes.

An Update on Strategies to Deliver Protein and Peptide Drugs to the Eye

In the past few decades, advancements in protein engineering, biotechnology, and structural biochemistry have resulted in the discovery of various techniques that enhanced the production yield of proteins, targetability, circulating half-life, product purity, and functionality of proteins and peptides. As a result, the utilization of proteins and peptides has increased in the treatment of many conditions, including ocular diseases. Ocular delivery of large molecules poses several challenges due to their high molecular weight, hydrophilicity, unstable nature, and poor permeation through cellular and enzymatic barriers. The use of novel strategies for delivering protein and peptides such as glycoengineering, PEGylation, Fc-fusion, chitosan nanoparticles, and liposomes have improved the efficacy, safety, and stability, which consequently expanded the therapeutic potential of proteins. This review article highlights various proteins and peptides that are useful in ocular disorders, challenges in their delivery to the eye, and strategies to enhance ocular bioavailability using novel delivery approaches. In addition, a few futuristic approaches that will assist in the ocular delivery of proteins and peptides were also discussed.

Utility of Anterior Segment OCT in the Management of Uveitic Cataract Surgery: A Fibrinoid Syndrome Case Treated with rtPA

PURPOSE

To highlight the importance of swept-source anterior segment optical coherence tomography (SS-ASOCT) in the peri-surgical management of cataract in uveitis. To describe a case of fibrinoid syndrome in uveitis treated with recombinant tissue plasminogen activator (rtPA).

METHODS

SS-ASOCT was performed at each follow-up before and after cataract surgery to assess anterior chamber inflammation and assist the clinical management of the patient.

RESULTS

A patient with idiopathic autoimmune uveitis was scheduled for cataract surgery. SS-ASOCT allowed to correctly plan the surgery timing. The patient developed a severe fibrinoid syndrome. Postsurgical SS-ASOCT allowed to distinguish between anterior chamber cells and fibrin thus guiding the timing for rtPA intracameral injection. Visual acuity improved from 20/400 the day after the surgery to 20/40.

CONCLUSION

SS-ASOCT allowed a precise assessment of the inflammatory components (cellular vs fibrinoid) after cataract surgery. Intracameral rtPA was safe and effective in the treatment fibrinoid syndrome in uveitis.

Anterior chamber fibrin reaction during Descemet membrane endothelial keratoplasty

Purpose

To report a series of five cases of intraoperative spontaneous anterior chamber fibrin reaction during Descemet Membrane Endothelial Keratoplasty (DMEK).

Methods

We retrospectively collected demographic data and data for ocular disease history for each patient. Donor age, preoperative graft endothelial density, surgical complications on surgery and intraoperative OCT videos, intraoperative management and outcome were assessed. The same standardized DMEK technique was used for all patients.

Results

We report intraoperative fibrin formation in five eyes subjected to DMEK. Three pseudophakic eyes underwent single DMEK, and the other two underwent combined DMEK and cataract surgery. In one case, a fibrin filament was observed before graft insertion, with multiplication during surgery, whereas, in the other four cases, strands of fibrin from the iris appeared after graft insertion. This complication resulted in graft failure in four cases (80%). No recipient- or donor-related risk factor was identified.

Conclusions and importance

The anterior chamber fibrin reaction is a very uncommon complication of DMEK. The underlying pathophysiological mechanisms remain unknown, but analyses of surgical videos and intraoperative OCT suggest iris involvement. This phenomenon may be induced by chronic subclinical anterior chamber inflammation, due to a blood-aqueous barrier breakdown associated with acute iris trauma during surgery. Thus, intraoperative microtraumatism of the iris should be avoided.

Tissue Plasminogen Activator Effects on Fibrin Volume and the Ocular Proteome in a Juvenile Rabbit Model of Lensectomy

Purpose

To investigate the use of tissue plasminogen activator (tPA) and its effects on the ocular proteome as a therapeutic intervention for postoperative inflammation and fibrin formation following intraocular lens (IOL) insertion in a juvenile rabbit model.

Methods

Twenty-six rabbits, 6 to 7 weeks old, underwent lensectomy with IOL insertion. Following examination on day 3, 100 µL of either 25 µg of recombinant rabbit tPA or balanced salt solution (control) was injected into the anterior chamber. On postoperative day 4, rabbits underwent examination, and eyes were harvested and fixed for 9.4-Tesla magnetic resonance imaging (MRI). Three masked observers quantified fibrin scar volume using Horos Project software. Aqueous humor (AH) was collected immediately prior to surgery and on postoperative days 3 and 4. Proteins related to coagulation and inflammation were assessed in AH samples using targeted mass spectrometry via parallel reaction monitoring.

Results

tPA significantly reduced the volume of fibrin 24 hours following administration compared with control eyes (0.560 mm³ vs. 3.29 mm³; P < 0.0001). Despite the reduced fibrin scar, proteins related to the coagulation and complement cascade were not significantly different following tPA injection.

Conclusions

tPA may be a safe candidate for reduction of postoperative fibrin scarring after intraocular surgery. MRI can provide a quantitative value for fibrin volume changes.

Translational Relevance

tPA is a candidate to treat ocular fibrin scarring. MRI can quantify the efficacy of treatments in future dose-response studies. Targeted mass spectrometry can provide critical data necessary to help decipher the effect on the abundance of targeted proteins following pharmacological intervention.

Intracameral r-tPA for the management of severe fibrinous reactions in TASS after cataract surgery

BACKGROUND

To describe the use of intracameral recombinant tissue plasminogen activator (r-tPA) in the treatment of severe fibrinous reactions in toxic anterior segment syndrome (TASS) after cataract surgery.

METHODS

A case series of 59 eyes of 59 patients with severe fibrinous anterior chamber reaction following cataract surgery who received intracameral r-tPA (25 µg/0.1 ml). The main outcome measures after intracameral r-tPA were the incidence of complete fibrinolysis, time of maximal effect, visual acuity, and complications.

RESULTS

Severe fibrinous reactions appeared 11.5 ± 5.3 days after cataract surgery. Fibrinolysis was observed 2.33 ± 2.70 days after rtPA use and 36 eyes (61%) exhibited resolution of the fibrin by the end of the first day following injection (p < 0.001). Transient corneal edema observed at 1-day after injection was the only complication reported during the injection of r-tPA or at follow-up. Eight eyes (13.6%) required a second r-tPA injection. Best-corrected visual acuity improved from 0.88 ± 0.67 logMAR units before rtPA injection to 0.48 ± 0.49 logMAR units at 1-month (p < 0.001).

CONCLUSIONS

The application of r-tPA was a quick and efficacious therapeutic approach for the management of severe fibrinous reactions in TASS after cataract surgery. In a clinical setting, intracameral r-tPA may be useful when rapid visual recovery is needed.

Successful pediatric DMEK facilitated by intracameral tissue plasminogen activator to mitigate anterior chamber fibrin reaction

Purpose

To report a case of a successful Descemet's membrane endothelial keratoplasty (DMEK) facilitated by the use of intracameral tissue plasminogen activator (tPA) in a 4-year old with posterior polymorphous corneal dystrophy (PPCD).

Observations

A 4-year old male was referred for bilateral corneal haze and blurry vision. Patient's exam and genetic testing were consistent with a diagnosis of PPCD. Patient was successfully treated with DMEK augmented by the use of intracameral tPA intraoperatively to combat the anterior chamber fibrin formation that can occur in DMEK.

Conclusions

To our knowledge, this case represents the youngest reported successful DMEK procedure and the first case describing the use of intracameral tPA intraoperatively to attenuate the anterior chamber fibrin formation that can occur in DMEK.

Effect of immediate postoperative intracameral tissue plasminogen activator (tPA) on anterior chamber fibrin formation in dogs undergoing phacoemulsification

OBJECTIVE

To evaluate the postoperative effect of intracameral tPA (alteplase; Activase®, Genentech, San Francisco, CA), administered at immediate conclusion of phacoemulsification, on anterior chamber fibrin formation in dogs.

PROCEDURES

Forty-one dogs (82 eyes) undergoing bilateral phacoemulsification received 25 μg/0.1 mL intracameral tPA in one eye and 0.1 mL unmedicated aqueous vehicle in the contralateral eye immediately after corneal incision closure. Intraocular pressure (IOP) was measured, and severity of anterior chamber fibrin formation, aqueous flare, pigment precipitates on the intraocular lens (IOL) implant, posterior capsular opacification (PCO), and corneal edema were graded at approximately 1 week, 2-3 weeks, 4-6 weeks, 8-12 weeks, and greater than 3 months postoperatively.

RESULTS

Anterior chamber fibrin developed postoperatively in 68.3% of dogs (28/41) and 50% of eyes (41/82). In tPA-treated eyes, 53.7% (22/41) developed fibrin compared to 46.3% of control eyes (19/41). Some degree of postoperative ocular hypertension (POH) occurred in 53.7% of dogs (22/41) and 36.5% of eyes (30/82). In tPA-treated eyes, 34.1% (14/41) experienced POH compared to 39% of control eyes (16/41). Additional intracameral tPA injection was later required in 29.3% of both tPA-treated (12/41) and control eyes (12/41).

CONCLUSIONS

Administration of intracameral tPA at immediate conclusion of canine phacoemulsification had no clinically observable effect on anterior chamber fibrin incidence at any time point. tPA-treated eyes showed no prophylaxis against POH or secondary glaucoma compared to control eyes and received late postoperative tPA injections at the same frequency as control eyes.

Effect of air bubble on inflammation after cataract surgery in rabbit eyes

Purpose:

Intense inflammation after cataract surgery can cause cystoid macular edema, posterior synechia and posterior capsule opacification. This experimental study was performed to investigate the effect of air bubble on inflammation when given to anterior chamber of rabbit eyes after cataract surgery.

Materials and Methods:

30 eyes of 15 rabbits were enrolled in the study. One of the two eyes was in the study group and the other eye was in the control group. After surgery air bubble was given to the anterior chamber of the study group eye and balanced salt solution (BSS; Alcon) was left in the anterior chamber of control eye.

Results:

On the first, second, fourth and fifth days, anterior chamber inflammations of the eyes were examined by biomicroscopy. On the sixth day anterior chamber fluid samples were taken for evaluation of nitric oxide levels as an inflammation marker. When the two groups were compared, in the air bubble group there was statistically less inflammation was seen. (1, 2, 4. days P = 0,001, and 5. day P = 0,009).

Conclusions:

These results have shown that when air bubble is left in anterior chamber of rabbits’ eyes after cataract surgery, it reduced inflammation. We believe that, air bubble in the anterior chamber may be more beneficial in the cataract surgery of especially pediatric age group, uveitis patients and diabetics where we see higher inflammation. However, greater and long termed experimental and clinical studies are necessary for more accurate findings.

Effect of low molecular weight heparin (enoxaparin) on congenital cataract surgery

AIM

To assess the efficacy of intracameral enoxaparin (a low-molecular-weight heparin) infusion, in variable doses on postoperative inflammatory response in congenital cataract surgery.

METHODS

It is a prospective, randomized controlled trial. Eighty eyes of 53 children with congenital cataract were enrolled in this study. Every eye had primary posterior capsulorrhexis and intraocular lens (IOL) implantation after lens aspiration. The eyes were divided into 4 equal groups. In group 1 balanced salt solution (BSS) without enoxaparin was used as an irrigation solution. Whereas in group 2, 3 and 4, 40mg, 20mg and 10mg enoxaparin in 500mL BSS was used respectively. The inflammatory response in the anterior chamber was compared among the groups with slit-lamp biomicroscopy.

RESULTS

The mean follow-up period was (17.75±3.95) months in group 1, (18.00±5.15) months in group 2, (19.20±5.47) months in group 3 and (18.65±5.16) months in group 4. Mean number of inflammatory cells in the anterior chamber in group 1 was significantly higher than that of group 2, 3, 4 (P<0.001). There was fibrin formation in the anterior chambers of 3 eyes in group 1 and one eye in group 4. There was synechiae formation in 3 eyes of group 1 and one eye of group 4. There was no significant difference among the groups by means of fibrin or synechiae formation (P>0.05). There were IOL precipitates in 4 eyes of group 1 and 2 eyes of group 4. IOL precipitate formation was significantly higher in group 1 than that of group 2 and 3 in which there was no IOL precipitate (P=0.048). There was IOL subluxation in only one eye of group 1, 3 and 4 while no subluxation was observed in group 2 (P>0.05). There was no statistically significant difference detected about IOL subluxation occurance in all 4 groups (P>0.05).

CONCLUSION

Complications of cataract surgery in congenital cataract patients associated with postoperative inflammatory response found to be decreased with the use of enoxaparin in intraocular infusion solutions. Furthermore according to our results the anti-inflammatory effect of enoxaparin was dose dependant.

Congenital and infantile cataract: aetiology and management

Congenital cataract is the commonest worldwide cause of lifelong visual loss in children. Although congenital cataracts have a diverse aetiology, in many children, a cause is not identified; however, autosomal dominant inheritance is commonly seen. Early diagnosis either on the post-natal ward or in the community is important because appropriate intervention can result in good levels of visual function. However, visual outcome is largely dependent on the timing of surgery when dense cataracts are present. Good outcomes have been reported in children undergoing surgery before 6 weeks of age in children with unilateral cataract and before 10 weeks of age in bilateral cases. Placement of an artificial intraocular lens implant after removal of the cataract has become established practice in children over 2 years of age. There remains debate over the safety and predictability of intraocular lens implantation in infants. Despite early surgery and aggressive optical rehabilitation, children may still develop deprivation amblyopia, nystagmus, strabismus, and glaucoma. The diagnosis and management of congenital cataracts has improved substantially over the past 30 years with a concurrent improvement in outcomes for affected children. Many aspects of the pre-, intra-, and postoperative management of these patients continue to be refined, highlighting the need for good quality data and prospective collaborative studies in this field.

Effect of intracameral cefuroxime on fibrinous uveitis after pediatric cataract surgery

PURPOSE

To determine whether intracameral cefuroxime reduces postoperative fibrin formation after pediatric cataract surgery.

METHODS

Children aged 3 months to 10 years with bilateral congenital or developmental cataracts who underwent surgery between February and July 2008 were eligible for inclusion in this prospective double-masked study. The same surgical technique was used in each eye. The intraocular lens was placed in either the bag or sulcus in both eyes. The same intraocular lens type was used in both eyes (polymethylmethacrylate). One eye was randomized to receive intracameral cefuroxime at the end of surgery and the fellow eye received saline. The surgeon was masked to the treatment assignment. The amount of fibrin formation in the anterior chamber of each eye was assessed by a masked grader on the fourth postoperative day.

RESULTS

Seventy eyes of 35 children were included in the study. Fibrin formation was noted on the fourth postoperative day in 14 of 70 eyes (20%), 7 in the cefuroxime group and 7 in the saline group. The mean fibrin score was 0.57 ± 1.31 in the cefuroxime group and 0.49 ± 1.07 in the saline group. There was no statistically significant difference in the amount of fibrin formation between groups (P = .857, Wilcoxon ranked signs test).

CONCLUSION

Intracameral cefuroxime did not significantly reduce postoperative fibrin formation in this study. Fibrin formation does not appear to be due to bacterial contamination in most cases of pediatric cataract surgery.

Effect of heparin in the intraocular irrigating solution on postoperative inflammation in the pediatric cataract surgery

Purpose:

To evaluate the influence of irrigation of the anterior chamber with heparin sodium on postoperative inflammation after pediatric cataract surgery.

Setting:

Kartal Training and Research Hospital, First Eye Clinic, Istanbul, Turkey.

Design:

Randomized prospective double-blind study.

Methods:

Fourteen consecutive eyes from 14 patients aged 8.9 ± 5.9 years, (range 3–18 years) (group 1) and 19 eyes from 19 patients aged 9.1 ± 5.2 (range 1.5–18 years) (group 2) underwent pediatric cataract surgery. Five patients in group 1 were between three and five years old. One patient was 1.5 years old and six patients in group 2 were between three and five years old. During the procedure, group 1 received anterior chamber irrigation with heparin sodium (5 IU/cc) and 1 ml of heparin sodium (concentration 10 IU/ml) added to the irrigating balanced salt solution (BSS Plus; Alcon Laboratories, Inc., Fort Worth, TX, USA) while group 2 received BSS without heparin sodium only. Cases aged under three years received anterior vitrectomy in addition to posterior capsulorrhexis. One eye received anterior vitrectomy in group 1 and two eyes received anterior vitrectomy in group 2. Cases with preoperative complications were not included in the study. Early and late postoperative inflammatory complications, including fibrin formation, anterior and posterior synechia, cyclitic and pupillary membrane formation were recorded and compared.

Results:

Mild anterior chamber reaction was observed in three patients in Group 1, while nine cases in group 2 experienced marked anterior chamber reaction. In four of nine patients from group 2, anterior chamber reaction was severe and resulted in pupillary membrane and synechia despite treatment in the postoperative 7th day, while in all three cases in group 1, reaction disappeared by the 7th day.

Conclusion:

Anterior chamber irrigation with heparin during pediatric cataract surgery may minimize early inflammatory reaction and decrease the number of postoperative inflammatory related complications.

Advances in the management of congenital and infantile cataract

Congenital and infantile cataracts produce deprivation amblyopia and can thus cause lifelong visual impairment. Successful management is dependent on early diagnosis and referral for surgery when indicated. Accurate optical rehabilitation and postoperative supervision are essential.The timing of surgery and its relationship to the duration of deprivation is important. Unilateral congenital cataract surgery within 6 weeks of birth produces the best outcomes. The equivalent 'latent' period for bilateral visual deprivation may be longer at around 10 weeks. Visual deprivation has a significant impact on the development of fixation stability. Major form deprivation, even after early surgery, leads to nystagmus. This is mostly manifest latent nystagmus (MLN). The latent period for fixation stability may be as short as 3 weeks. Preoperative congenital nystagmus (CN) can convert to more benign MLN after surgery. Infantile IOL implantation is becoming increasingly accepted. A satisfactory long-term refractive result requires that allowance be made for childhood axial growth and myopic shift. In a series of 25 infants (33 eyes) implanted before 12 months of age, the mean myopic shift at 12 months was 4.83 D. This increased to 5.3 D in infants implanted before 10 weeks. The initial desired refractive outcome following IOL implantation is thus hypermetropia, with the degree dependent on the age of the child. Glaucoma or ocular hypertension is a common complication following paediatric cataract surgery. Microphthalmia and surgery in early infancy are risk factors. Tonometry results may be influenced by the increased corneal thickness seen in aphakic and pseudophakic children. The long-term prognosis of eyes with aphakic glaucoma is not necessarily poor but intraocular pressure control may require three or more medications. Surgical intervention appears to be necessary in over a quarter of eyes. Posterior capsule opacification (PCO) is common in infants undergoing primary lens implantation. Primary capsulotomy and anterior vitrectomy reduce the risk of PCO. In the absence of anterior vitrectomy, primary posterior capsulotomy does not prevent visual axis opacification. Further developments will continue to be driven by clinical research. The prevention of capsule opacification and cellular proliferation may in future be achieved by the use of devices to specifically target epithelial cells at surgery.

Intracameral recombinant tissue plasminogen activator for the treatment of severe fibrin reaction in endophthalmitis

PURPOSE

The authors sought to evaluate the efficacy of recombinant tissue plasminogen activator (r-TPA) in the treatment of severe fibrinous anterior chamber reactions secondary to endophthalmitis.

METHODS

Twelve patients with endophthalmitis associated with severe fibrinous anterior chamber reactions were enrolled in the study. Various degrees of posterior synechiae were noted in 10 of these patients. TPA (25 microg/0.05 cc) was injected into the anterior chamber through the limbus as an adjunctive treatment to intravitreal antibiotic injection. Efficacy of the treatment was judged by the rate of fibrinolysis, the lysis of posterior synechiae, and the size of the dilated pupil.

RESULTS

After application of 25 microg of r-TPA, the fibrin reaction gradually resolved in 2-14 h. The median dilated pupil size in ratio 24 h after r-TPA injection was significantly larger than before r-TPA injection (0.41 vs 0.60; P=0.002). The median difference in pupil size in ratio in patients with posterior synechiae larger than 180 degrees was significantly larger than those with posterior synechiae equal or less than 180 degrees (0.32 vs 0.09; P=0.003). At 24 h after application of r-TPA, no eye had posterior synechiae.

CONCLUSION

Intracameral injection of r-TPA may be a safe and effective method for the treatment of significant fibrin reaction in endophthalmitis and thus facilitates vitreous and fundus examinations and vitrectomy if necessary.

Recombinant Tissue Plasminogen Activator (r-TPA) in Fibrin Dissolution due to Postoperative Endophthalmitis

Key words: Cataract surgery, Fibrinolysis, Infection

Intraoperative enoxaparin minimizes inflammatory reaction after pediatric cataract surgery

PURPOSE

To evaluate the effect of intraocular infusion of enoxaparin, a low-molecular-weight heparin, on postoperative inflammatory response in pediatric cataract surgery.

DESIGN

Prospective, comparative, consecutive interventional case series.

METHODS

Seventeen consecutive eyes (11 patients) underwent pediatric cataract surgery in two tertiary medical centers. During the procedure, balanced salt solution with enoxaparin (40 mg in 500 ml) was infused into the anterior chamber. Eleven consecutive eyes (eight patients) received balanced salt solution without enoxaparin in the infusion bottle. The inflammatory response in the anterior chamber was compared between the two groups by semiquantification with slit-lamp biomicroscopy. Postoperative inflammatory complications, including fibrin formation, intraocular lens precipitates, anterior and posterior synechiae, cyclitic and pupillary membrane formation, and anterior subluxation of the intraocular lens, were also compared. The follow-up period after surgery was between 3 and 36 months (average 12.3 months).

RESULTS

The number of cells and the degree of flare were minimal in the group with enoxaparin in the infusion bottle (P < .001). The total number of postoperative inflammation-related complications was also lower in the enoxaparin-treated group (P = .007). All corneas remained clear, and the endothelial cell count, which was performed in two patients, did not show substantial decrease in their density or changes in shape and size. No other enoxaparin-related complications were observed.

CONCLUSIONS

Infusion of enoxaparin during pediatric cataract surgery may minimize the postoperative inflammatory response and decrease the number of postoperative inflammatory related complications. Enoxaparin should also be evaluated for cataract surgery in other conditions where postoperative inflammation may be exacerbated.

Intracameral tissue plasminogen activator to prevent severe fibrinous effusion after congenital cataract surgery

BACKGROUND/AIMS

To evaluate the efficacy of intracameral recombinant tissue plasminogen activator (r-TPA) in prevention of fibrinous effusion after lensectomy, anterior vitrectomy, and posterior chamber intraocular lens (PCIOL) implantation in patients with congenital cataract.

METHODS

The study was done as a double masked randomised clinical trial between April 2002 and November 2003 in Farabi Eye Hospital. 34 eyes of 26 patients with congenital cataract were included in the study and randomised into two groups (18 cases and 16 controls). Mean age was 8.1 years (3--14 years). Each eye underwent lensectomy and anterior vitrectomy with PCIOL implantation. At the end of surgery 20 microg r-TPA was injected intra-camerally in the case group. The control group received only balanced salt solution. All patients received periocular, systemic, and topical steroids after surgery. Patients underwent follow up examinations for 3 months.

RESULTS

The incidence of intraocular fibrin membrane formation was significantly lower in the case group on days 1, 3, 7, 14 (p=0.02, p=0.01, p=0.01, and p=0.01, respectively, chi(2) test), but there was no significant difference on days 30 and 90. The frequency of pigmented intraocular lens precipitates was significantly lower in the case group at the end of the third month (p<0.001, chi(2) test). No gross ocular side effects were noted after r-TPA injection.

CONCLUSION

It seems that prophylactic intracameral r-TPA is effective in prevention of fibrinous effusion at least in the first 2 weeks after cataract extraction in the paediatric age group and decreases the incidence of pigmented IOL precipitates.

Retroprosthetic membranes in AlphaCor patients: risk factors and prevention

PURPOSE

To report retroprosthetic membrane (RPM) formation in association with AlphaCor and identify risk factors for their formation and strategies for prevention and management.

METHODS

Review of AlphaCor data and case histories and literature review.

RESULTS

RPMs occurred with AlphaCor in 14 (9.3%) cases. We find significant associations with systemic risk factors (race, hypertension, diabetes mellitus) rather than ocular history, but perioperative management may also be related to risk of RPM development. Histology demonstrates a fibrovascular tissue resembling scarred corneal tissue. Similar histologic findings have been reported for other devices.

CONCLUSION

Retrocorneal membranes and RPMs with earlier keratoprostheses have frequently been reported without specific identifiable causes. Diabetes is known to be associated with intraocular membrane formation. This study demonstrates that systemic factors affect the risk of RPM formation with AlphaCor. In cases identified as at greater risk of membrane formation, peri- and postoperative therapies such as steroids, non-steroidals, heparin or rTPA should be considered. In our series, several therapeutic and surgical strategies appear effective but recognizing patients at increased risk pre-operatively and using preventive measures where indicated is likely to be key to minimizing the incidence of this complication.

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.

Use of dapsone in the treatment of Pneumocystis carinii pneumonia in a foal

A 6-month-old male Quarter Horse was evaluated for chronic respiratory tract disease. Diagnostic investigations revealed pulmonary inflammation; Pneumocystis carinii was detected within macrophages. Lymphocyte subpopulation phenotyping and immunoglobulin concentration analysis were performed and results suggested immune suppression. Trimethoprim-sulfamethoxazole administration was initiated; the colt was discharged but was reexamined 8 days later because of profuse diarrhea and endotoxemia. Bacterial culture of feces recovered Salmonella spp resistant to trimethoprim-sulfamethoxazole, and a diagnosis of antimicrobial-associated colitis was made. Bilateral fibrinous hypopyon developed and was treated with topical medication and intracameral injections of human recombinant tissue plasminogen activator. Dapsone (3 mg/kg [1.4 mg/lb], PO, q 24 h; dose extrapolated from human data) was administered for treatment of P carinii pneumonia (56-day treatment period). The colt recovered from the pneumonia and diarrhea. Dapsone may be a useful adjunct to traditional treatment for P carinii pneumonia in horses or as a sole medication for horses that cannot tolerate other treatments.

Intraocular lens implantation for traumatic cataract in children in East Africa

PURPOSE

To review the visual outcomes and complications after intraocular lens (IOL) implantation in children with traumatic cataract in sub-Saharan Africa, where contact lenses for unilateral aphakia are impractical in most patients.

SETTING

PCEA Kikuyu Eye Unit, Nairobi, Kenya, East Africa.

METHODS

All children younger than 16 years having IOL implantation for traumatic cataract between February 1993 and December 1998 (215 eyes) were retrospectively reviewed. Complications and visual outcomes were evaluated.

RESULTS

The study group comprised 147 boys and 68 girls. The median interval between injury and cataract surgery was 8 weeks. The most common causes of injury were stick (36.3%) and thorn (10.7%). Extracapsular cataract extraction with IOL implantation was performed in all patients. The most frequent early complication was fibrinous uveitis in 110 eyes (51.2%). One hundred sixty-seven eyes (77.7%) had 1 month or more follow-up. Of those, 108 eyes (64.7%) had a best corrected visual acuity of 20/60 or better. Twenty-one eyes (12.6%) had a visual acuity of worse than 20/200, with the most common causes being amblyopia (9/21) and retinal detachment (5/21). Amblyopia was found in 42 of 108 (38.9%) children aged 8 years or less at the time of injury. Eyes with the IOL in the capsular bag were significantly less likely to require subsequent capsulotomy (P <.01) during the 2-year follow-up.

CONCLUSION

The results indicate that posterior chamber IOLs can be safely implanted by experienced surgeons in most children older than 2 years with traumatic cataract and should be the standard of care throughout the world.