Primary angle closure glaucoma is characterized by altered extracellular matrix homeostasis in the iris

PURPOSE

To characterize the proteome of the iris in primary angle closure glaucoma (PACG).

EXPERIMENTAL DESIGN

In this cross-sectional study, iris samples were obtained from surgical iridectomy of 48 adults with PACG and five normal controls. Peptides from iris were analysed using liquid chromatography-tandem mass spectrometry on an Orbitrap Q Exactive Plus mass spectrometer. Verification of proteins of interest was conducted using selected reaction monitoring on a triple quadrupole mass spectrometer. The main outcome was proteins with a log₂ two-fold difference in expression in iris between PACG and controls.

RESULTS

There were 3,446 non-redundant proteins identified in human iris, of which 416 proteins were upregulated and 251 proteins were downregulated in PACG compared with controls. Thirty-two upregulated proteins were either components of the extracellular matrix (ECM) (fibrillar collagens, EMILIN-2, fibrinogen, fibronectin, matrilin-2), matricellular proteins (thrombospondin-1), proteins involved in cell-matrix interactions (integrins, laminin, histidine-rich glycoprotein, paxillin), or protease inhibitors known to modulate ECM turnover (α-2 macroglobulin, tissue factor pathway inhibitor 2, papilin). Two giant proteins, titin and obscurin, were up- and down-regulated, respectively, in the iris in PACG compared with controls.

CONCLUSIONS AND CLINICAL RELEVANCE

This proteomic study shows that ECM composition and homeostasis are altered in the iris in PACG.

Long-term outcomes of the Ahmed glaucoma valve surgery in childhood glaucoma

PURPOSE

To report the rates of success of Ahmed glaucoma valve (AGV) surgery in early childhood glaucoma and factors associated with success.

METHODS

Children with primary congenital or early childhood secondary glaucoma who underwent AGV surgery over a 10-year period (one eye per child) at a single institution were identified. Surgical failure was defined as having one or more of the following: intraocular pressure of >21 mm Hg 3 months postoperatively, reoperation for glaucoma, and vision loss to no light perception.

RESULTS

A total of 178 patients were identified (median age, 5.8 ± 5.5 years): 125 with primary congenital and 53 with secondary childhood glaucoma. The success rate at 1 year was 92% (95% CI, 88%-96%); at 5 years, 64% (95% CI, 55%-73%); and at 10 years, 36% (95% CI, 25%-52%). Younger age at baseline (P = 0.003) and secondary childhood glaucoma (P = 0.045) were associated with lower success.

CONCLUSIONS

The AGV is associated with high short-term success in children with primary congenital glaucoma, but the 10-year success rates are poor. Younger age and secondary childhood glaucoma may be associated with a more refractory outcome.

Outcomes of Ahmed Glaucoma Valve Revision in Pediatric Glaucoma

PURPOSE

Encapsulation of the Ahmed glaucoma valve (AGV) plate is a common cause for postoperative elevation of intraocular pressure, especially in children. Many reports have described the outcomes of AGV revision in adults. However, the outcomes of AGV revision in children are poorly documented. The aim of this study was to determine the outcomes of AGV revision in children.

DESIGN

Retrospective cross-sectional study.

METHODS

A retrospective chart review of patients less than 15 years of age who underwent AGV revision with a minimum postoperative follow-up of 6 months was conducted. Outcome measures included reduction in intraocular pressure from baseline, survival analysis, and reduction in the number of antiglaucoma medications. Postoperative complications were also noted. Complete success was defined as an IOP of 21 mm Hg or less without medications, while qualified success was defined as having an IOP of 21 mm Hg or less with medications.

RESULTS

A total of 44 eyes met the inclusion criteria. Primary congenital glaucoma was present in 39 eyes (88.6%), aphakic glaucoma in 4 eyes (9.1%), and Peters anomaly-associated glaucoma in 1 eye (2.3%). The mean number of previous surgeries was 1.4, and the mean age was 6.7 years (range, 1.9-13 years) with a median follow-up of 12 months (range, 6-24 months). The IOP was reduced from a preoperative mean of 30.4 (± 10.3) to 24.9 (± 10.6) mm Hg at 6 months postoperatively. Kaplan-Meier analysis showed that the complete success rate at 1 month was 100% followed by a rapid decline at 6 months to 38.6%, 27.7% at 1 year, and 5.5% at 2 years. Qualified success rate was 100% at 1 month followed by a 6-month and 1-year survival rate of approximately 50% and a 2-year survival rate of approximately 16%. The median survival time was 14 months. No specific risk factors for failure were identified. Visual acuity remained unchanged following revision. The most common complication was recurrence of encapsulation with elevated IOP (15.9%). Other complications included hyphema (n = 3; 6.8%), endophthalmitis (n = 1; 2.3%), wound leak (n = 1; 2.3%), and choroidal detachment (n = 2; 4.5%).

CONCLUSION

Although the short-term success rate of AGV revision in children is high, with longer follow-up the success rate decreases significantly.

Long-term follow up of surgical repair of late bleb leaks after glaucoma filtering surgery

PURPOSE

To study the long-term outcomes of surgical revision of leaking blebs after trabeculectomy and identify possible risk factors for failure.

PATIENT AND METHODS

A retrospective, nonrandomized, noncomparative interventional study of 34 eyes with late bleb leaks after trabeculectomy that underwent bleb excision with conjunctival advancement. The primary outcome measure was successful repair and control of intraocular pressure (IOP). The other measures evaluated included change in visual acuity from baseline and complications such as recurrence of bleb leak, endophthalmitis or the need for additional antiglaucoma medication to control IOP.

RESULTS

After a mean follow up of 36.2+/-23 months, the mean IOP at the last visit was 14.5+/-7.6 mm Hg. IOP in 58.8% of eyes was controlled without medication. Complications included early leaks (7/34), late recurrent or persistent leaks (1/34), and endophthalmitis (1/34). In all, 41.2% patients required additional medication at the last visit. Survival analysis at 22 months the probability of total and qualified success was 52% and 72%, respectively. However, this dropped to 10% and 15%, respectively, at 5 years. The probability of total and qualified success further dropped to 2.5% and 5% at 5 years when the IOP cut-off was lowered from 21 to 15 mm Hg. Cox regression analysis failed to identify risk factors for bleb failure.

CONCLUSIONS

Surgical bleb revision seems to be effective in treating late bleb leaks with few postoperative complications. However, patients should be followed carefully as late failure of bleb function beyond 2 years is a significant possibility.

Side-effect profile of brimonidine tartrate in children

PURPOSE

To investigate brimonidine-related side effects and the efficacy of brimonidine in lowering intraocular pressure (IOP) in children with primary infantile and secondary glaucoma.

STUDY DESIGN

Single-center, prospective, interventional, noncomparative case series.

PARTICIPANTS

Eighty-three children (mean age, 7.84 years) met the inclusion criteria.

METHODS

Medical records were reviewed to identify children with primary infantile or other forms of secondary pediatric glaucoma from birth to 15 years who received brimonidine as adjunctive therapy for glaucoma. The parents of the children who met the inclusion criteria completed a detailed questionnaire-based interview. The children were examined to assess weight, major systemic effects, and efficacy of adjunctive brimonidine therapy.

MAIN OUTCOME MEASURES

Questionnaire-based interview of parents to assess side effects of brimonidine and IOP-lowering effect of adjunctive brimonidine.

RESULTS

Parents reported symptoms in 70 of 83 children (84%). The most common side effects were excessive sleepiness and lethargy (76%), eye itching and rubbing (49%), and stinging and burning of the eyes (39%). Logistic regression analysis showed a statistically significant independent association between age and weight with lethargy and sleepiness. In symptomatic patients, symptoms' frequency increased with low weight (<20 kg) and in the young (<6 years). Mean IOP reduction after initiation of brimonidine, mainly as an adjunct, was 5+/-6.7 mmHg (P<0.001).

CONCLUSIONS

Side effects after the use of brimonidine in children were frequent. The weight and age of the child were important factors in predicting central nervous system side effects, especially excessive sleepiness and lethargy. Although brimonidine is effective in lowering IOP in children, alternative glaucoma therapy should be considered especially in children weighing <20 kg and those younger than 6 years.

Correlation between surgical success rate and severity of congenital glaucoma

AIM

To study the correlation between severity of primary congenital glaucoma (PCG) and success of three types of surgery.

METHODS

This was a retrospective review of all records of patients diagnosed with PCG up to age 1 year who underwent goniotomy, trabeculotomy, or combined trabeculotomy-trabeculectomy with mitomycin C as initial procedure between 1982 and 2002 at the King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. 532 paediatric glaucoma patients below age 1 year (820 eyes) with a minimum 1 year follow up were identified. The main outcome measures used for the surgeries were postoperative intraocular pressure, stability of the corneal diameter, and maintenance of corneal clarity. Surgical success was defined as a postoperative intraocular pressure of < or = 21 mm Hg without additional medical or surgical therapy, and with decreased corneal oedema, stabilised corneal diameter, and no additional optic nerve damage for at least 1 year after surgery. Complications, time of surgical failure, and follow up were recorded.

RESULTS

The eyes were grouped into mild (249), moderate (342), and severe (229) PCG, based on intraocular pressure, corneal diameter, and clarity. All three surgical procedures resulted in high success rates of 81-100% for the mild form of PCG. Eyes classified with moderate glaucoma had a 13%, 40%, and 80% success rate respectively for goniotomy, trabeculotomy, and combined trabeculotomy-trabeculectomy with mitomycin C. The success rate for severe PCG was 10% and 70% for trabeculotomy and combined surgery respectively. Goniotomy was never done for eyes with this condition.

CONCLUSION

Clinical classification of PCG is helpful for surgical decision making. The mild form has a high surgical success regardless of the procedure chosen. Combined trabeculotomy-trabeculectomy with mitomycin C gave the best results for moderate and severe cases of PCG.

Endophthalmitis associated with the Ahmed glaucoma valve implant

AIM

To investigate the rate, risk factors, clinical course, and treatment outcomes of endophthalmitis following glaucoma drainage implant (GDI) surgery.

METHODS

A computerised relational database search was conducted to identify all patients who were implanted with Ahmed glaucoma valve (AGV) and developed endophthalmitis following surgery at the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia, between 1 January 1994 and 30 November 2003. Only medical records of the patients who developed endophthalmitis were retrospectively reviewed.

RESULTS

542 eyes of 505 patients who were on active follow up were included in the study. Endophthalmitis developed in nine (1.7%) eyes; the rate was five times higher in children than in adults. Delayed endophthalmitis (developed 6 weeks after surgery) occurred in eight of nine eyes. Conjunctival erosion overlying the AGV tube was present in six of nine eyes. Common organisms isolated in the vitreous included Haemophilus influenzae and Streptococcus species. Multiple regression analysis revealed that younger age and conjunctival erosion over the tube were significant risk factors associated with endophthalmitis.

CONCLUSION

Endophthalmitis is a rare complication of GDI surgery that appears to be more common in children. Conjunctival dehiscence over the GDI tube seems to represent a major risk factor for endophthalmitis. Prompt surgical revision of an exposed GDI tube is highly recommended.