Trabecular Procedures Combined with Cataract Surgery for Open-Angle Glaucoma: A Report by the American Academy of Ophthalmology

PURPOSE

To determine the intraocular pressure (IOP) reduction of various trabecular procedures (a form of minimally invasive glaucoma surgery [MIGS]) combined with cataract surgery compared with cataract surgery alone, to compare the safety of the various trabecular procedures, and to highlight patient characteristics that may favor one trabecular procedure over another.

METHODS

A search of English-language peer-reviewed literature in the PubMed database was initially conducted in February 2021 and updated in April 2023. This yielded 279 articles. Twenty studies met initial inclusion and exclusion criteria and were assessed for quality by the panel methodologist. Of these, 10 were rated level I, 3 were rated level II, and 7 were rated level III. Only the 10 level I randomized controlled trials (RCTs) were included in this assessment, and all were subject to potential industry-sponsorship bias.

RESULTS

The current analysis focuses on the amount of IOP reduction (in studies that involved medication washout) and on IOP reduction with concurrent medication reduction (in studies that did not involve medication washout). Based on studies that performed a medication washout, adding a trabecular procedure to cataract surgery provided an additional 1.6 to 2.3 mmHg IOP reduction in subjects with hypertensive, mild to moderate open-angle glaucoma (OAG) at 2 years over cataract surgery alone, which itself provided approximately 5.4 to 7.6 mmHg IOP reduction. In other words, adding a trabecular procedure provided an additional 3.8% to 8.9% IOP reduction over cataract surgery alone, which itself provided 21% to 28% IOP reduction. There was no clear benefit of one trabecular procedure over another. Patient-specific considerations that can guide procedure selection include uveitis predisposition, bleeding risk, metal allergy, and narrowing of Schlemm's canal. There are no level I data on the efficacy of trabecular procedures in subjects with pretreatment IOP of 21 mmHg or less.

CONCLUSIONS

Trabecular procedures combined with cataract surgery provide an additional mild IOP reduction over cataract surgery alone in hypertensive OAG subjects. Additional research should standardize outcome definitions, avoid industry sponsorship bias, and study the efficacy of these procedures in normotensive OAG.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Aqueous Shunts with Extraocular Reservoir for Open-Angle Adult Glaucoma: A Report by the American Academy of Ophthalmology

PURPOSE

To evaluate the recently published literature on the efficacy and safety of the use of aqueous shunts with extraocular reservoir for the management of adult open-angle glaucomas (OAGs).

METHODS

A search of peer-reviewed literature was last conducted in April 2023 of the PubMed database and included only articles published since the last aqueous shunt Ophthalmic Technology Assessment, which assessed articles published before 2008. The abstracts of these 419 articles were examined, and 58 studies were selected for full-text analysis. After inclusion and exclusion criteria were applied, 28 articles were selected and assigned ratings by the panel methodologist according to the level of evidence. Twenty-five articles were rated level I and 3 articles were rated level II. There were no level III articles.

RESULTS

Implantation of aqueous shunts with extraocular reservoir can lower intraocular pressure (IOP) by between one-third and one-half of baseline IOP, depending on whether it is undertaken as the primary or secondary glaucoma surgery. Success rates for aqueous shunts were found to be better than for trabeculectomies in eyes with prior incisional surgery. Conversely, in eyes without prior incisional surgery, implantation of aqueous shunts was found to have an overall lower success rate as the primary glaucoma procedure compared with trabeculectomy. Although both valved and nonvalved aqueous shunts with extraocular reservoir were effective, the nonvalved device generally achieved slightly lower long-term IOPs with fewer glaucoma medications and less need for additional glaucoma surgery. Both devices slow the rates of visual field progression with efficacy comparable with that of trabeculectomy. Early aqueous humor suppression after aqueous shunt implantation is recommended for the management of the postoperative hypertensive phase and long-term IOP control. No strong evidence supports the routine use of mitomycin C with aqueous shunt implantation for OAG.

CONCLUSIONS

Implantation of aqueous shunts with extraocular reservoir, including valved or nonvalved devices, has been shown to be an effective strategy to lower IOP. Strong level I evidence supports the use of aqueous shunts with extraocular reservoir by clinicians for the management of adult OAG.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Central Visual Field Testing in Early Glaucoma: A Report by the American Academy of Ophthalmology

PURPOSE

To evaluate the current published literature on the utility of the 10-2 visual field (VF) testing strategy for the evaluation and management of early glaucoma, defined here as mean deviation (MD) better than -6 decibels (dB).

METHODS

A search of the peer-reviewed literature was last conducted in June 2023 in the PubMed database. Abstracts of 986 articles were examined to exclude reviews and non-English-language articles. After inclusion and exclusion criteria were applied, 26 articles were selected, and the panel methodologist rated them for strength of evidence. Thirteen articles were rated level I, and 8 articles were rated level II. The 5 level III articles were excluded. Data from the 21 included articles were abstracted and reviewed.

RESULTS

The central 12 locations on the 24-2 VF test grid lie within the central 10 degrees covered by the 10-2 VF test. In early glaucoma, defects detected within the central 10 degrees generally agree between the 2 tests. Defects within the central 10 degrees of the 24-2 VF test can predict defects on the 10-2 VF test, although the 24-2 may miss defects detected on the 10-2 VF test. In addition, results from the 10-2 VF test show better association with findings from OCT scans of the macular ganglion cell complex. Modifications of the 24-2 test that include extra test locations within the central 10 degrees improve detection of central defects found on 10-2 VF testing.

CONCLUSIONS

Evidence to date does not support routine testing using 10-2 VF for patients with early glaucoma. However, early 10-2 VF testing may provide sufficient additional information for some patients, particularly those with a repeatable defect within the central 12 locations of the standard 24-2 VF test or who have inner retinal layer thinning on OCT scans of the macula.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Selective Laser Trabeculoplasty for the Treatment of Glaucoma: A Report by the American Academy of Ophthalmology

PURPOSE

To review the current published literature for high-quality studies on the use of selective laser trabeculoplasty (SLT) for the treatment of glaucoma. This is an update of the Ophthalmic Technology Assessment titled, "Laser Trabeculoplasty for Open-Angle Glaucoma," published in November 2011.

METHODS

Literature searches in the PubMed database in March 2020, September 2021, August 2022, and March 2023 yielded 110 articles. The abstracts of these articles were examined to include those written since November 2011 and to exclude reviews and non-English articles. The panel reviewed 47 articles in full text, and 30 were found to fit the inclusion criteria. The panel methodologist assigned a level I rating to 19 studies and a level II rating to 11 studies.

RESULTS

Data in the level I studies support the long-term effectiveness of SLT as primary treatment or as a supplemental therapy to glaucoma medications for patients with open-angle glaucoma. Several level I studies also found that SLT and argon laser trabeculoplasty (ALT) are equivalent in terms of safety and long-term efficacy. Level I evidence indicates that perioperative corticosteroid and nonsteroidal anti-inflammatory drug eye drops do not hinder the intraocular pressure (IOP)-lowering effect of SLT treatment. The impact of these eye drops on lowering IOP differed in various studies. No level I or II studies exist that determine the ideal power settings for SLT.

CONCLUSIONS

Based on level I evidence, SLT is an effective long-term option for the treatment of open-angle glaucoma and is equivalent to ALT. It can be used as either a primary intervention, a replacement for medication, or an additional therapy with glaucoma medications.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Corneal Hysteresis for the Diagnosis of Glaucoma and Assessment of Progression Risk: A Report by the American Academy of Ophthalmology

PURPOSE

To review the current published literature on the utility of corneal hysteresis (CH) to assist the clinician in the diagnosis of glaucoma or in the assessment of risk for disease progression in existing glaucoma patients.

METHODS

Searches of the peer-reviewed literature in the PubMed database were performed through July 2022. The abstracts of 423 identified articles were examined to exclude reviews and non-English articles. After inclusion and exclusion criteria were applied, 19 articles were selected, and the panel methodologist rated them for level of evidence. Eight articles were rated level I, and 5 articles were rated level II. The 6 articles rated level III were excluded.

RESULTS

Corneal hysteresis is lower in patients with primary open-angle glaucoma, primary angle-closure glaucoma, pseudoexfoliative glaucoma, and pseudoexfoliation syndrome compared with normal subjects. Interpretation of low CH in patients with high intraocular pressure (IOP) or on topical hypotensive medications is complicated by the influence of these parameters on CH measurements. However, CH is also lower in treatment-naïve, normal-tension glaucoma patients compared with normal subjects who have a similar IOP. In addition, lower CH is associated with an increased risk of progression of glaucoma based on visual fields or structural markers in open-angle glaucoma patients, including those with apparently well-controlled IOP.

CONCLUSIONS

Corneal hysteresis is lower in glaucoma patients compared with normal subjects, and lower CH is associated with an increased risk of disease progression. However, a causal relationship remains to be demonstrated. Nevertheless, measurement of CH complements current structural and functional assessments in determining disease risk in glaucoma suspects and patients.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Association of Brain Volume and Retinal Thickness in the Early Stages of Alzheimer's Disease

BACKGROUND

The eye has been considered a 'window to the brain,' and several neurological diseases including neurodegenerative conditions like Alzheimer's disease (AD) also show changes in the retina.

OBJECTIVE

To investigate retinal nerve fiber layer (RNFL) thickness and its association with brain volume via magnetic resonance imaging (MRI) in older adults with subjective or objective cognitive decline.

METHODS

75 participants underwent ophthalmological and neurological evaluation including optical coherence tomography and MRI (28 cognitively normal subjects, 26 with subjective cognitive decline, 17 patients diagnosed with mild cognitive impairment, and 4 with AD). Differences in demographics, thickness of RNFL, and brain volume were assessed using ANCOVA, while partial Pearson correlations, covaried for age and sex, were used to compare thickness of the peripapillary RNFL with brain volumes, with p < 0.05 considered statistically significant.

RESULTS

Mean RNFL thickness was significantly correlated with brain volumes, including global volume (right eye r = 0.235 p = 0.046, left eye r = 0.244, p = 0.037), temporal lobe (right eye r = 0.242 p = 0.039, left eye r = 0.290, p = 0.013), hippocampal (right eye r = 0.320 p = 0.005, left eye r = 0.306, p = 0.008), amygdala (left eye r = 0.332, p = 0.004), and occipital lobe (right eye r = 0.264 p = 0.024) volumes.

CONCLUSION

RNFL thickness in both eyes was positively associated with brain volumes in subjects with subjective and objective cognitive decline. The RNFL, however, did not correlate with the disease, but the small sample number makes it important to conduct larger studies. RNFL thickness may be a useful non-invasive and inexpensive tool for detection of brain neurodegeneration and may assist with diagnosis and monitoring of progression and treatment in AD.

OCT Angiography for the Diagnosis of Glaucoma: A Report by the American Academy of Ophthalmology

PURPOSE

To review the current published literature on the use of OCT angiography (OCTA) to help detect changes associated with the diagnosis of primary open-angle glaucoma.

METHODS

Searches of the peer-reviewed literature were conducted in March 2018, June 2018, April 2019, December 2019, and June 2020 in the PubMed and Cochrane Library databases. Abstracts of 459 articles were examined to exclude reviews and non-English articles. After inclusion and exclusion criteria were applied, 75 articles were selected and the panel methodologist rated them for strength of evidence. Three articles were rated level I and 57 articles were rated level II. The 15 level III articles were excluded.

RESULTS

OCT angiography can detect decreased capillary vessel density within the peripapillary nerve fiber layer (level II) and macula (level I and II) in patients with suspected glaucoma, preperimetric glaucoma, and perimetric glaucoma. The degree of vessel density loss correlates significantly with glaucoma severity both overall and topographically (level II) as well as longitudinally (level I). For differentiating glaucomatous from healthy eyes, some studies found that peripapillary and macular vessel density measurements by OCTA show a diagnostic ability (area under the receiver operating characteristic curve) that is comparable with structural OCT retinal nerve fiber and ganglion cell thickness measurements, whereas other studies found that structural OCT measurements perform better. Choroidal or deep-layer microvasculature dropout as measured by OCTA is also associated with glaucoma damage (level I and II). Lower peripapillary and macular vessel density and choroidal microvasculature dropout are associated with faster rates of disease progression (level I and II).

CONCLUSIONS

Vessel density loss associated with glaucoma can be detected by OCTA. Peripapillary, macular, and choroidal vessel density parameters may complement visual field and structural OCT measurements in the diagnosis of glaucoma.

Visual contrast sensitivity is associated with the presence of cerebral amyloid and tau deposition

Visual deficits are common in neurodegenerative diseases including Alzheimer’s disease. We sought to determine the association between visual contrast sensitivity and neuroimaging measures of Alzheimer’s disease-related pathophysiology, including cerebral amyloid and tau deposition and neurodegeneration. A total of 74 participants (7 Alzheimer’s disease, 16 mild cognitive impairment, 20 subjective cognitive decline, 31 cognitively normal older adults) underwent the frequency doubling technology 24-2 examination, a structural MRI scan and amyloid PET imaging for the assessment of visual contrast sensitivity. Of these participants, 46 participants (2 Alzheimer’s disease, 9 mild cognitive impairment, 12 subjective cognitive decline, 23 cognitively normal older adults) also underwent tau PET imaging with [¹⁸F]flortaucipir. The relationships between visual contrast sensitivity and cerebral amyloid and tau, as well as neurodegeneration, were assessed using partial Pearson correlations, covaried for age, sex and race and ethnicity. Voxel-wise associations were also evaluated for amyloid and tau. The ability of visual contrast sensitivity to predict amyloid and tau positivity were assessed using forward conditional logistic regression and receiver operating curve analysis. All analyses first were done in the full sample and then in the non-demented at-risk individuals (subjective cognitive decline and mild cognitive impairment) only. Significant associations between visual contrast sensitivity and regional amyloid and tau deposition were observed across the full sample and within subjective cognitive decline and mild cognitive impairment only. Voxel-wise analysis demonstrated strong associations of visual contrast sensitivity with amyloid and tau, primarily in temporal, parietal and occipital brain regions. Finally, visual contrast sensitivity accurately predicted amyloid and tau positivity. Alterations in visual contrast sensitivity were related to cerebral deposition of amyloid and tau, suggesting that this measure may be a good biomarker for detecting Alzheimer’s disease-related pathophysiology. Future studies in larger patient samples are needed, but these findings support the power of these measures of visual contrast sensitivity as a potential novel, inexpensive and easy-to-administer biomarker for Alzheimer’s disease-related pathology in older adults at risk for cognitive decline.

The Effect of Molecular Weight on Passage of Proteins Through the Blood-Aqueous Barrier

Purpose

To determine the effect of molecular weight (MW) on the concentration of plasma-derived proteins in aqueous humor and to estimate the plasma-derived and eye-derived fractions for each protein.

Methods

Aqueous humor and plasma samples were obtained during cataract surgery on an institutional review board-approved protocol. Protein concentrations were determined by ELISA and quantitative antibody microarrays. A total of 93 proteins were studied, with most proteins analyzed using 27 to 116 aqueous and 6 to 30 plasma samples.

Results

Plasma proteins without evidence of intraocular expression by sequence tags were used to fit a logarithmic model relating aqueous-plasma ratio (AH:PL) to MW. The log(AH:PL) appears to be well predicted by the log(MW) (P < 0.0001), with smaller proteins such as cystatin C (13 kDa) having a higher AH:PL (1:6) than larger proteins such as albumin (66 kDa, 1:300) and complement component 5 (188 kDa, 1:2500). The logarithmic model was used to calculate the eye-derived intraocular fraction (IOF) for each protein. Based on the IOF, 66 proteins could be categorized as plasma-derived (IOF<20), whereas 10 proteins were primarily derived from eye tissue (IOF >80), and 17 proteins had contribution from both plasma and eye tissue (IOF 20-80).

Conclusions

Protein concentration of plasma-derived proteins in aqueous is nonlinearly dependent on MW in favor of smaller proteins. Our study demonstrates that for proper interpretation of results, proteomic studies evaluating changes in aqueous humor protein levels should take into account the plasma and eye-derived fractions.

Gender Differences in Case Volume Among Ophthalmology Residents

Importance

Although almost equal numbers of male and female medical students enter into ophthalmology residency programs, whether they have similar surgical experiences during training is unclear.

Objective

To determine differences for cataract surgery and total procedural volume between male and female residents during ophthalmology residency.

Design, Setting, Participants

This retrospective, longitudinal analysis of resident case logs from 24 US ophthalmology residency programs spanned July 2005 to June 2017. A total of 1271 residents were included. Data were analyzed from August 12, 2017, through April 4, 2018.

Main Outcomes and Measures

Variables analyzed included mean volumes of cataract surgery and total procedures, resident gender, and maternity or paternity leave status.

Results

Among the 1271 residents included in the analysis (815 men [64.1%]), being female was associated with performing fewer cataract operations and total procedures. Male residents performed a mean (SD) of 176.7 (66.2) cataract operations, and female residents performed a mean (SD) of 161.7 (56.2) (mean difference, -15.0 [95% CI, -22.2 to -7.8]; P < .001); men performed a mean (SD) of 509.4 (208.6) total procedures and women performed a mean (SD) of 451.3 (158.8) (mean difference, -58.1 [95% CI, -80.2 to -36.0]; P < .001). Eighty-five of 815 male residents (10.4%) and 71 of 456 female residents (15.6%) took parental leave. Male residents who took paternity leave performed a mean of 27.5 (95% CI, 13.3 to 41.6; P < .001) more cataract operations compared with men who did not take leave, but female residents who took maternity leave performed similar numbers of operations as women who did not take leave (mean difference, -2.0 [95% CI, -18.0 to 14.0]; P = .81). From 2005 to 2017, each additional year was associated with a 5.5 (95% CI, 4.4 to 6.7; P < .001) increase in cataract volume and 24.4 (95% CI, 20.9 to 27.8; P < .001) increase in total procedural volume. This increase was not different between genders for cataract procedure volume (β = -1.6 [95% CI, -3.7 to 0.4]; P = .11) but was different for total procedural volume such that the increase in total procedural volume over time for men was greater than that for women (β = -8.0 [95% CI, -14.0 to -2.1]; P = .008).

Conclusions and Relevance

Female residents performed 7.8 to 22.2 fewer cataract operations and 36.0 to 80.2 fewer total procedures compared with their male counterparts from 2005 to 2017, a finding that warrants further exploration to ensure that residents have equivalent surgical training experiences during residency regardless of gender. However, this study included a limited number of programs (24 of 119 [20.2%]). Future research including all ophthalmology residency programs may minimize the selection bias issues present in this study.

The acute and chronic effects of intravitreal anti-vascular endothelial growth factor injections on intraocular pressure: A review

The acute and chronic effects of repeated intravitreal antivascular endothelial growth factor (VEGF) injections on intraocular pressure have not been fully characterized, and the development of sustained ocular hypertension could adversely affect patients who are at risk of glaucomatous optic neuropathy. As expected, volume-driven, acute ocular hypertension immediately follows intravitreal injection, but this pressure elevation is generally transient and well tolerated. Several medications have been investigated to limit acute ocular hypertension following anti-VEGF therapy, but the benefits of pretreatment are not conclusive. Chronic, sustained ocular hypertension, distinct from the short-term acute ocular hypertension after each injection, has also been associated with repeated intravitreal anti-VEGF injections. Risk factors for chronic ocular hypertension include the total number of injections, a greater frequency of injection, and preexisting glaucoma. Proposed mechanisms for chronic ocular hypertension include microparticle obstruction, toxic or inflammatory effects on trabecular meshwork, as well as alterations in outflow facility by anti-VEGF agents. Although limiting anti-VEGF therapy could minimize the risk of both acute and chronic ocular hypertension, foregoing anti-VEGF therapy risks progression of various macular diseases with resulting permanent central vision loss. While definitive evidence of damage to the retinal nerve fiber layer is lacking, patients receiving repeated injections should be monitored for ocular hypertension and patients in whom sustained ocular hypertension subsequently developed should be periodically monitored for glaucomatous changes with optic nerve optical coherence tomography and static visual fields.

The effect of prior trabeculectomy on refractive outcomes of cataract surgery

PURPOSE

To examine surgical and refractive outcomes of phacoemulsification with intraocular lens (IOL) implant in eyes with prior trabeculectomy.

DESIGN

Retrospective observational case-control study.

METHODS

The study compared eyes that underwent phacoemulsification with IOL implant at least 3 months post-trabeculectomy (n = 77) with eyes with either medically controlled glaucoma (n = 43) or no glaucoma (n = 50) at an academic institution. The main outcome measure was the difference between the expected and the actual postoperative refraction.

RESULTS

Mean intraocular pressure (IOP) increased in trabeculectomy eyes from 8.7 ± 4.2 mm Hg to 10.7 ± 4.0 mm Hg (P < .0001), whereas it decreased in glaucoma control and normal control groups by 2.0 mm Hg (P = .003) and 2.1 mm Hg (P < .00001), respectively, with concurrent decrease in drops in the glaucoma control group (0.76 to 0.23, P < .0001). The difference from expected refractive outcome was -0.36 (more myopic) in trabeculectomy eyes compared with +0.23 (more hyperopic) in nonglaucoma controls and +0.40 in glaucoma controls (P < .0001). The correlation between change in IOP vs extent of refractive surprise was statistically significant (P = .01, r = -0.20). Final visual acuity was not affected by the difference in refractive error.

CONCLUSIONS

The refractive surprise correlated to IOP change, with 2 mm Hg rise resulting in a -0.36 diopter shift between predicted and actual refraction. After cataract extraction, IOP decreased in controls and fewer drops were required, but IOP increased in the study group. Factors affecting refractive surprise in cataract surgery after trabeculectomy, especially IOP change and axial length, require further investigation.

Bilateral sequential nonarteritic anterior ischemic optic neuropathy: a comparison of visual outcomes in fellow eyes using quantitative analysis of goldmann visual fields

OBJECTIVE

To better define the concordance of visual loss in patients with nonarteritic anterior ischemic optic neuropathy (NAION).

METHODS

The medical records of 86 patients with bilateral sequential NAION were reviewed retrospectively, and visual function was assessed using visual acuity, Goldmann visual fields, color vision, and relative afferent papillary defect. A quantitative total visual field score and score per quadrant were analyzed for each eye using the numerical Goldmann visual field scoring method.

RESULTS

Outcome measures were visual acuity, visual field, color vision, and relative afferent papillary defect. A statistically significant correlation was found between fellow eyes for multiple parameters, including logMAR visual acuity (P=.01), global visual field (P<.001), superior visual field (P<.001), and inferior visual field (P<.001). The mean deviation of total (P<.001) and pattern (P<.001) deviation analyses was significantly less between fellow eyes than between first and second eyes of different patients.

CONCLUSIONS

Visual function between fellow eyes showed a fair to moderate correlation that was statistically significant. The pattern of vision loss was also more similar in fellow eyes than between eyes of different patients. These results may help allow better prediction of visual outcome for the second eye in patients with NAION.

Mechanobiology of trabecular meshwork cells

Trabecular meshwork (TM) cells likely play a key role in regulating outflow facility and hence intraocular pressure. They function in a dynamic environment subjected to variations in mechanical and fluid shear forces. Because the extent of mechanical stress on the trabecular meshwork is dependent on the intraocular pressure, the behavior of TM cells under mechanical strain may suggest mechanisms for how outflow facility is regulated. Studies have demonstrated that TM cells respond in a variety of ways to mechanical loads, including increased extracellular matrix turnover, altered gene expression, cytokine release, and altered signal transduction. This review highlights some of the considerations and limitations of studying the mechanobiology of TM cells.

Central corneal thickness and visual field loss in fellow eyes of patients with open-angle glaucoma

PURPOSE

To determine the relationship of central corneal thickness (CCT) and visual field loss between fellow eyes in primary open-angle glaucoma.

DESIGN

Retrospective, observational case series.

METHODS

Records review of glaucoma patients seen at local Veterans Administration eye clinic. Those with CCT measurements performed within one month of visual field testing were included. Patients were excluded with vision below 20/40 or disease that would affect visual fields. Intrasubject (between fellow eyes) differences in CCT, mean deviation (MD), and pattern standard deviation (PSD) were calculated by subtracting left eye value from right eye value.

RESULTS

Of the 100 subjects (94 males), the Spearman correlation coefficient between intrasubject differences in CCT vs intrasubject differences in MD was 0.36 (P = .0003). The Spearman correlation for differences in CCT vs differences in PSD was -0.31 (P = .0019).

CONCLUSIONS

Our study suggests that worse visual field changes tend to occur in the eye with the thinner cornea.

Clinical Experience with the Baerveldt 250-mm2 Glaucoma Implant

PURPOSE

To report the intermediate-term results of the Baerveldt 250-mm2 Glaucoma Implant for treatment of adult glaucoma.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

One hundred eight adult patients (108 eyes) with glaucoma who received a Baerveldt 250-mm2 Glaucoma Implant.

INTERVENTION

Implantation of the Baerveldt 250-mm2 Glaucoma Implant.

MAIN OUTCOME MEASURES

Intraocular pressure (IOP), visual acuity, number of glaucoma medications, and surgical complications. Success was defined as IOP > or = 6 mmHg and < or = 21 mmHg (with or without antiglaucoma medications), without further glaucoma surgery, devastating complication, or loss of light perception attributable to drainage implantation.

RESULTS

Mean age was 63.8+/-16.5 years. Mean postoperative follow-up was 22.8 months (range, 0.2-84.9; interquartile range, 3.9-36.3). Mean preoperative IOP was 36.3+/-13.0 mmHg, on 2.9+/-1.1 antiglaucoma medications. The mean postoperative IOP at final visit was 15.8+/-7.6 mmHg (P<0.0001, paired t test), on 0.8+/-1.0 antiglaucoma medications (P<0.0001, Wilcoxon test). Kaplan-Meier success rates were 0.92 (6 months, n = 81), 0.88 (12 months, n = 75), 0.84 (18 months, n = 68), and 0.79 (24 months, n = 61).

CONCLUSIONS

The Baerveldt 250-mm2 Glaucoma Implant provides good intermediate-term success for the treatment of adult refractory glaucoma.

Surgical Drainage of Choroidal Effusions Following Glaucoma Surgery

PURPOSE

To determine the efficacy and safety of surgical drainage of choroidal effusions that occurs following glaucoma surgical procedures.

PATIENTS AND METHODS

Ninety-four choroidal drainage procedures performed at a single institution from 1986 to 2001 were reviewed retrospectively. Sixty-three eyes of 63 persons who underwent one or more drainage procedures for choroidal effusions that developed following glaucoma surgical procedures were identified. Eyes diagnosed with suprachoroidal hemorrhage prior to intervention were excluded. The cases were evaluated for resolution of choroidal detachment, post-drainage complications, visual acuity, and intraocular pressure before and after drainage.

RESULTS

Indications for choroidal drainage included flat anterior chamber (25 eyes), decreased vision (22 eyes), and persistent choroidal detachment (16 eyes). Complete resolution of choroidal effusions was achieved in 37 (59%) eyes by 1 month, 51 (81%) eyes by 2 months, and in 57 (90%) eyes by 4 months following the initial drainage procedure. Overall success rate per procedure at 12 months was 77% (60/78). Compared with pre-drainage, intraocular pressure was higher at 6 and 12 months post-drainage (P < 0.0001) and visual acuity was better at 6 and 12 months post-drainage (logMAR, P < 0.0001). Twenty-seven (77%) of 35 phakic eyes developed cataracts during the 12 months post-drainage.

CONCLUSIONS

Choroidal effusions that develop after glaucoma surgery can usually be drained with minimal complications. Surgical drainage is associated with improved vision and resolution of hypotony. Cataracts may progress following choroidal drainage but this may be due to the pre-drainage hypotony conditions.

Effect of temporal corneal phacoemulsification on intraocular pressure in eyes with prior trabeculectomy with an antimetabolite1 , *1

OBJECTIVE

To evaluate the effect of temporal corneal phacoemulsification on intraocular pressure (IOP) in eyes after primary trabeculectomy with intraoperative fluorouracil (5-FU) or mitomycin C (MMC).

DESIGN

Retrospective case-control study.

PATIENTS

Twenty-nine patients who were participants in a prospective randomized double-masked trial comparing the efficacies of intraoperative 5-FU and MMC and who underwent temporal corneal phacoemulsification after the primary trabeculectomy were matched to 29 patients enrolled in the same study who did not undergo cataract surgery. The 2 groups were matched for length of follow-up after the trabeculectomy and the antimetabolite used at the time of trabeculectomy.

METHODS

Comparisons of IOP, visual acuity (VA), and the number of glaucoma medications were made between the 2 groups and within the groups at various follow-up intervals to detect any statistically significant differences.

MAIN OUTCOME MEASURES

Intraocular pressure before phacoemulsification and at various times postoperatively were compared with IOP in the control group at the matched follow-up times.

RESULTS

The mean of all IOP measurements beyond 3 months after phacoemulsification for each subject was significantly higher than the prephacoemulsification IOP (11.8+/-4.2 vs. 8.7+/-4.5 mmHg; P = 0.00003, paired t test). In contrast, the mean IOP remained stable in the control group during the equivalent time period (9.6+/-3.5 vs. 9.1+/-3.1 mmHg; P = 0.42, paired t test). Postphacoemulsification IOP was significantly higher than the corresponding IOP in the time-matched control group (P<0.003, analysis of covariance). Mean VA improved significantly after the phacoemulsification (P = 0.0002) but remained stable in the control group.

CONCLUSION

Temporal corneal phacoemulsification can affect long-term IOP control after trabeculectomy with 5-FU or MMC.

Ocular hypotensive efficacy of bimatoprost 0.03% and travoprost 0.004% in patients with glaucoma or ocular hypertension

PURPOSE

To evaluate the IOP-lowering efficacy of bimatoprost and travoprost for the treatment of glaucoma and ocular hypertension.

METHODS

Randomized, investigator-masked, parallel-group clinical trial. After completing a washout from all glaucoma medications, patients (n=26) were randomized to bimatoprost or travoprost for 6 months. Visits were at baseline, week 1, and months 1, 3, and 6. IOP was measured at 9 am at each visit and also at 1 and 4 pm at baseline and months 3 and 6.

RESULTS

At the baseline visit, there were no significant between-group differences in IOP at 9 am, 1 pm, or 4 pm (P> or =.776). After 6 months of therapy, both medications provided significant mean reductions from baseline IOP at every time point (P< or =.007). Mean IOP reductions ranged from 7.4 mm Hg to 8.8 mm Hg (34% to 36%) with bimatoprost and from 4.6 mm Hg to 7.2 mm Hg (19% to 29%) with travoprost (P> or =.057) after 6 months of medication. At the final study visit, more patients achieved low target pressures with bimatoprost than with travoprost at each time point. Both study medications were well tolerated and ocular redness was the most commonly reported adverse event in both treatment groups.

CONCLUSION

Although both bimatoprost and travoprost effectively lowered IOP in patients with glaucoma or ocular hypertension, bimatoprost provided larger mean IOP reductions than travoprost. More patients achieved low target pressures with bimatoprost than with travoprost. The between-group differences were not statistically significant due to the small sample size. These findings are being further evaluated in an ongoing multicenter clinical trial.

Morphologic classification of filtering blebs after glaucoma filtration surgery: the Indiana Bleb Appearance Grading Scale

PURPOSE

To establish a new classification system for filtering blebs according to clinical morphologic parameters. The purpose of this classification system is to provide a uniform and objective assessment of bleb appearance and establish a framework system through which outcomes of filtration surgery may be better correlated to clinical morphology.

MATERIALS AND METHODS

The Indiana Bleb Appearance Grading Scale contains a set of photographic standards illustrating a range of filtering bleb morphology selected from the slide library of the Glaucoma Service at the Indiana University Department of Ophthalmology. These standards consist of slit lamp images for grading bleb height, extent, vascularity, and leakage with the Seidel test. For grading, the morphologic appearance of the filtration bleb is assessed relative to the standard images for the 4 parameters and scored accordingly. Fifty-one clinical bleb photographs were evaluated and scored by 3 glaucoma subspecialists in a masked fashion according to the scale.

RESULTS

For all of the grading scales, high interobserver agreement was found using the scale to classify the appearance of filtering blebs (height +0.76; extent +0.78; vascularity +0.90, interclass correlation coefficient for consistency using a 2-way mixed effect model).

CONCLUSION

The Indiana Bleb Appearance Grading Scale is a simple, reproducible, yet comprehensive system for classifying the morphologic slit lamp appearance of filtration blebs.

A prospective randomized trial comparing intraoperative 5-fluorouracil vs mitomycin C in primary trabeculectomy

PURPOSE

To compare the safety and efficacy of intraoperative 5-fluorouracil (5-FU) or Intraoperative mitomycin C (MMC) in eyes undergoing primary trabeculectomy.

DESIGN

Prospective double-masked randomized clinical trial.

METHODS

One hundred fifteen eyes of 103 patients with uncontrolled intraocular pressure (IOP) despite maximally tolerated medical therapy or laser were prospectively randomized in a double-masked fashion to one of two treatment groups in a single institution setting. Subject's eyes underwent primary trabeculectomy with either topical 5-FU (50 mg/ml for 5 minutes) or topical MMC (0.2 mg/ml for 2 minutes). Primary outcome measures included the number of eyes achieving target pressures of 21, 18, 15, and 12 mm Hg at 6 and 12 months postoperatively. Secondary outcome measures included IOP, best-corrected visual acuity, complications, and interventions.

RESULTS

Of the 115 eyes, 57 received 5-FU while 58 received MMC. A target IOP of 21 mm Hg at 6 months was achieved in 53 of 56 (95%) eyes in the 5-FU group and 54 of 57 (95%) eyes in the MMC group (P = 1.00). At 12 months, 45 of 48 (94%) eyes in the 5-FU group met a target IOP of 21 mm Hg while 48 of 54 (89%) eyes in the MMC group did (P =.49). The most common complications in each group were persistent choroidal effusions and bleb leak.

CONCLUSION

Our study suggests that intraoperative topical 5-FU is at least as effective as intraoperative topical MMC in reducing IOP of eyes undergoing primary trabeculectomy.

Up-regulation of brain-derived neurotrophic factor expression by brimonidine in rat retinal ganglion cells

OBJECTIVES

Brimonidine tartrate ophth, an alpha(2)-adrenergic agonist, is widely used as an antiglaucoma agent for lowering intraocular pressure. Recent studies suggest that brimonidine may be neuroprotective for retinal ganglion cells (RGCs) following optic nerve crush injury. Brain-derived neurotrophic factor (BDNF), a potent neuroprotective factor present in the RGCs, promotes RGC survival in culture and following optic nerve injury. We tested the hypothesis that a possible mechanism of brimonidine neuroprotection is through up-regulation of endogenous BDNF expression in the RGCs.

METHODS

A single dosage of brimonidine tartrate ophth solution (0.85-34 microM) was injected intravitreally into Sprague-Dawley rat eyes. The fellow eyes of each animal were injected with balanced salt solution (BSS) and used as control eyes. To determine BDNF messenger RNA expression, animal eyes were enucleated and processed for in situ hybridization, or retinas were isolated and processed for Northern blot analysis using rat BDNF radiolabeled riboprobes.

RESULTS

In the control eyes injected with saline, BDNF was present in a minority of the RGCs. Two days after brimonidine injection, the number of BDNF-positive RGCs was increased from 55% to 166%, depending on brimonidine concentrations, when compared with those in the controls. In addition, the BDNF signal intensities in individual RGCs were elevated 50% in brimonidine-injected eyes compared with control eyes. Northern blot revealed a 28% increase of BDNF expression in the brimonidine group compared with the controls (P <.003). No significant difference was observed in BDNF receptor, trk B, expression between brimonidine, or BSS control groups.

CONCLUSIONS

A single dose of a low concentration of intravitreal brimonidine is sufficient to significantly increase endogenous BDNF expression in RGCs. These results suggest that brimonidine neuroprotection may be mediated through up-regulation of BDNF in the RGCs. The BDNF should be further investigated regarding its role in the neuroprotective effects reported with brimonidine.

CLINICAL RELEVANCE

Brimonidine may be (potentially) used clinically as a neuroprotective agent in optic neuropathy, including glaucoma, and ischemic and traumatic optic neuropathy.

Genetic basis of glaucoma

The application of molecular genetic techniques to the study of glaucoma has accelerated greatly during the past few years. In addition to localizing and identifying genes for specific types of glaucoma, researchers have begun to characterize the gene products and investigate molecular mechanisms involved in glaucoma. Much research has been focused on the gene expression, protein processing, and mutations of MYOC/TIGR, which is associated with both juvenile-and adult-onset primary open angle glaucoma. Investigations of other glaucoma-related genes, such as PITX2, FOXC1, and CYP1B1, are enabling a better understanding of anterior segment development and its relation to glaucoma.

Conjunctival advancement versus nonincisional treatment for late-onset glaucoma filtering bleb leaks

OBJECTIVE

To compare the outcomes of conjunctival advancement and nonincisional management of late-onset glaucoma filtering bleb leak.

DESIGN

Retrospective, nonrandomized, comparative interventional trial.

PARTICIPANTS

Fifty-one eyes of 48 persons who underwent management of late-onset glaucoma filtering bleb leak from December 1986 through December 1999 were included. Thirty-seven eyes were included in the nonincisional treatment group (aqueous suppression with lubrication or patching, bandage contact lenses, cyanoacrylate glue, autologous blood injection, or a combination thereof) and 34 eyes were included in the surgical revision group (conjunctival advancement with preservation of the preexisting bleb). Twenty eyes underwent nonincisional treatment before surgical revision and were included in each treatment group.

METHODS

Retrospective chart review of bleb leaks occurring at least 2 months after trabeculectomy. Successful treatment was defined as the resolution of the bleb leak, a final intraocular pressure (IOP) of 21 mmHg or less, and no significant complications such as blebitis, endophthalmitis, or bleb dysesthesia requiring a bleb revision.

MAIN OUTCOME MEASURES

Cumulative success of closure of the filtering bleb leak, complications resulting from the intervention, IOP before and after treatment, and number of glaucoma medications before and after treatment.

RESULTS

The Kaplan-Meier cumulative probability of success at 12 and 24 months were 0.45 and 0.42, respectively, for the nonincisional treatment group and 0.80 and 0.80, respectively, for the surgical revision group. The overall difference between the cumulative success of surgical and nonincisional treatment was statistically significant (P = 0.0001, log-rank test). In the nonincisional treatment group, only 20 of 37 eyes (54%) achieved initial sealing of the bleb leak after the treatment, and of those, almost half (8/20) eventually failed. Reasons for failure included persistent or recurrent leak (n = 21), blebitis or endophthalmitis (n = 6, including 4 with persistent leak), and bleb dysesthesia (n = 2). All eyes in the surgical group achieved closure of the leak, however 7 eventually failed because of leak recurrence (n = 2), elevated IOP (n = 3), or bleb dysesthesia (n = 2), and 11 required additional glaucoma medications.

CONCLUSIONS

Patients with late bleb leaks managed with conjunctival advancement were more likely to have successful outcomes and less likely to have serious intraocular infections than those managed more conservatively.

Delayed suprachoroidal hemorrhage after glaucoma filtration procedures

OBJECTIVES

To determine the incidence of, risk factors for, and outcomes of delayed suprachoroidal hemorrhage (DSCH) after glaucoma filtration surgery.

DESIGN

Retrospective case-control study.

PARTICIPANTS

All patients undergoing glaucoma filtration procedures between 1986 and 2000 at Indiana University who were diagnosed postoperatively with suprachoroidal hemorrhage. A total of 66 patients with DSCH were identified. These were compared with a randomly selected group of patients who underwent similar procedures but did not have suprachoroidal hemorrhage.

METHODS

Total cases of DSCH were initially compared with the total number of glaucoma surgeries to determine the overall incidence and the incidence in the different procedures. Subsequently, a case-control study was performed comparing the group with hemorrhage to the control group to identify risk factors. Finally, outcomes and prognostic factors were determined by comparing vision preoperatively and postoperatively and parameters of patients with good and poor outcomes.

MAIN OUTCOME MEASURES

Incidence of DSCH, risk factors associated with its occurrence, visual outcomes, and factors important for prognosis.

RESULTS

Of a total of 2285 glaucoma filtration procedures, 66 (2.9%) cases of DSCH were identified. It developed in 9 of 615 (1.5%) trabeculectomies without antimetabolite, 30 of 1248 (2.4%) trabeculectomies with antimetabolite, 2 of 72 (2.8%) valved tube shunt implantations, and 25 of 350 (7.1%) nonvalved tube shunt implantations. The increased incidence of DSCH after tube shunts compared with trabeculectomy-associated DSCH was significant (P < 0.0001) with an odds ratio of 3.2. The risk factors for DSCH after glaucoma surgery include white race (P = 0.012), anticoagulation (P = 0.034), severe postoperative hypotony (P = 0.033), and aphakia/anterior chamber intraocular lens (P = 0.002). The visual outcomes of patients with hemorrhage were poor, with a decrease in logarithm of the minimum angle of resolution visual acuity from 0.72 to 1.36, which was statistically significant compared with the controls (P < 0.009).

CONCLUSIONS

Delayed suprachoroidal hemorrhage occurs more frequently after tube shunt implantation than after trabeculectomy. Caution should be exercised when operating on patients with known risk factors, because the visual outcomes after DSCH are poor.

Autologous blood injection for late-onset filtering bleb leak

PURPOSE

To report the outcomes of autologous blood injections for late-onset filtering bleb leak.

METHODS

Retrospective chart review of all eyes that had autologous blood injection(s) for filtering bleb leak occurring at least 2 months after trabeculectomy at the Indiana University Medical Center. Successful treatment was defined as resolution of the bleb leak and no need for additional glaucoma medications. Failure was defined as a persistent bleb leak, intraocular pressure greater than 21 mm Hg, or the occurrence of a vision-threatening event related to the procedure.

RESULTS

Thirty-two eyes of 31 patients had autologous blood injection for filtering bleb leak and were followed for a mean of 4.9 months (SD, 9.2; range, 1 to 37 months). Twenty-three eyes (72%) were outright failures because of persistence of the leak. Nine eyes (28%) had an initially successful outcome, but the success rate decreased over time as bleb leaks recurred in three of the nine eyes at 5, 6, and 37 months. No patient characteristics correlated with outcome. Mean intraocular pressure increased from pretreatment to final examination (4.5 to 6.5 mm Hg, P =.003). Mean logarithm of minimal angle of resolution (logMAR) vision remained unchanged from pretreatment to final examination (P =.55). Blood seepage into the anterior chamber after autologous blood injection was common but transient.

CONCLUSIONS

Autologous blood injection is of limited success in treating late-onset filtering bleb leak.

The effect of mechanical strain on matrix metalloproteinase production by bovine trabecular meshwork cells

PURPOSE

To evaluate the effects of mechanical stretching of trabecular meshwork cells on matrix metalloproteinase activity.

METHODS

Cultured bovine trabecular meshwork cells grown on collagen-coated elastomer were subjected to 10% biaxial mechanical stretching. After various time intervals, culture medium was collected from stretched and non-stretched control cells. Matrix metalloproteinase activity was studied by zymography and levels of inhibitors were determined by immunoblotting or immunoassay of the collected medium.

RESULTS

Trabecular meshwork cells subjected to mechanical strain showed increased stromelysin and gelatinase A activity at 24 to 72 hours after initial stretching compared to control cells. By 72 hours of strain, stromelysin activity increased to up to 73% (p < 0.01) whereas gelatinase A activity increased by 31% (p < 0.05). The increased metalloproteinase activity was reversible with relaxation of mechanical stretch. Levels of tissue inhibitor of matrix metalloproteinase-1 and -2 remained unchanged during 72 hours of stretch.

CONCLUSIONS

Changes in mechanical strain on the trabecular meshwork, which may occur in vivo during changes in intraocular pressure, induce changes in matrix metalloproteinase activity. The resultant alterations in the extracellular matrix may affect outflow resistance through the trabecular meshwork in response to alterations in intraocular pressure.

Cataract surgery after tube shunts

PURPOSE

To determine the effect of cataract surgery on glaucomatous eyes with functioning tube shunts.

METHODS

Retrospective analysis of 11 eyes of 11 patients with functioning tube shunts who underwent cataract extraction.

RESULTS

The mean follow-up after cataract extraction was 21 +/- 27 months (range, 4-97 months). There was no statistically significant difference between the mean preoperative intraocular pressure and mean postoperative intraocular pressure (17.4 +/- 3.7 mm Hg vs 17.8 +/- 5.9 mmHg; P = 0.85, paired t test). Most patients exhibited a statistically significant rise or drop in pressure, but in none was there a clinically significant change. The mean number of preoperative and postoperative antiglaucoma medications was also not significantly different (1.5 +/- 1.1 vs 1.7 +/- 1.2; P = 0.44, paired t test). Snellen visual acuity improved at least 2 lines in 6 eyes (55%). Complications after cataract extraction included corneal edema in three eyes, one of which had subsequent loss of control of intraocular pressure.

CONCLUSIONS

Eyes with a functioning tube shunt undergoing cataract extraction can maintain control of intraocular pressure while achieving visual improvement.

Shunt revision versus additional tube shunt implantation after failed tube shunt surgery in refractory glaucoma

PURPOSE

To compare tube shunt revision with additional tube shunt after failed tube shunt surgery.

METHODS

We identified 281 patients who underwent a primary tube shunt procedure from 1985 to 1998 at Indiana University and reviewed 33 eyes of 33 patients that had failed and required further surgery. Shunt revision was performed in 12, whereas an additional shunt was placed in 21 eyes. Intraocular pressure, antiglaucoma medications, visual acuity, and complications were noted. Success was defined as at least a 25% reduction in intraocular pressure that was deemed clinically adequate. Qualified success was defined as a 25% intraocular pressure reduction but with additional medications or a significant reduction in medications with stable intraocular pressure for preoperative intraocular pressure less than 21 mm Hg.

RESULTS

Preoperative intraocular pressures (mean +/- 95% confidence interval) for the revision and additional tube groups were 28.8 +/- 5.8 mm Hg and 29.8 +/- 2.7 mm Hg (P =.73), with an average follow-up period of 25.2 months (range, 3 to 108 months) and 34.8 months (range, 6 to 84 months), respectively. Final mean intraocular pressure was 25.3 +/- 6.7 mm Hg for the revision group and 17.7 +/- 3.4 mm Hg for the additional tube group (P =.037). Forty-two percent in the revision group versus 62% in the additional tube group achieved at least a qualified success (P =.30, Fisher exact test). Corneal edema was a common complication, especially in the additional tube group. Limitations of this study include the small sample sizes and the uneven distribution of neovascular glaucoma between the two groups (six of 12 in the revision group vs two of 21 in the additional tube group; P =.015, Fisher exact test).

CONCLUSIONS

Our series showed that after failed tube shunt surgery, an additional tube shunt offers better intraocular pressure control than revision by excision of an encapsulated bleb.

Outcomes of sequential tube shunts in complicated glaucoma

OBJECTIVE

To evaluate intraocular pressure (IOP) control, change in visual acuity, and complications in eyes that have undergone a second glaucoma tube shunt procedure.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Twenty-two eyes of 22 patients that have undergone sequential tube implants for management of glaucoma.

METHODS

Parameters analyzed included IOP, visual acuity, and number of hypotensive agent before each shunt procedure and at last follow-up visit. The overall IOP lowering effect attributable to each tube shunt was calculated. Any ocular complications after the second tube shunt were recorded. Success was defined as an IOP between 6 and 21 mm Hg and a 20% reduction in IOP from the second tube shunt procedure. Qualified successes met one of these two requirements at the last follow-up visit. Total failures did not meet any of the above criteria, required additional surgical intervention to lower IOP, or both.

MAIN OUTCOME MEASURES

Intraocular pressure control, visual acuity preservation, and complications.

RESULTS

At the last follow-up visit, the average percent reduction in IOP from both tube shunt procedures was 42+/-21%. The average percent IOP reduction from the second tube shunt was 33+/-17%. Eleven (50%) patients met the criteria for success, 8 (36.4%) patients were qualified successes, and 3 (13.6%) were failures. The median number of hypotensive agents decreased from two to one. Ten patients experienced new or worse pseudophakic bullous keratopathy after the second tube shunt, six of whom underwent penetrating keratoplasty. Thirteen (59%) patients maintained visual acuity within one line of their second tube shunt pre-operative Snellen visual acuity. Seven (32%) patients lost more than 2 lines, and one patient lost light perception.

CONCLUSIONS

Although corneal morbidity is a common complication, a second tube shunt does not cause higher-than-expected rates of other complications associated with tube shunt surgery. Eyes that undergo a second tube shunt procedure can achieve pressure control, require fewer hypotensive agents, and may maintain stable visual acuity.

Combined penetrating keratoplasty and trabeculectomy with mitomycin C

OBJECTIVE

To evaluate corneal graft survival and intraocular pressure control in eyes that have undergone combined penetrating keratoplasty and trabeculectomy with mitomycin C (MMC).

DESIGN

Retrospective noncomparative case series.

INTERVENTION

Penetrating keratoplasty combined with trabeculectomy with MMC and other surgical procedures.

PARTICIPANTS

Twenty-four eyes of 22 patients undergoing combined penetrating keratoplasty and trabeculectomy with mitomycin C.

MAIN OUTCOME MEASURES

Corneal graft clarity and intraocular pressure control.

RESULTS

The cumulative probability of corneal graft survival was 85% at 1 year and 60% at 2 years. The cumulative probability of adequate pressure control was 67% at 3 months, 55% at 12 months, and 50% at 24 months. The incidence of bleb failure was higher in cases involving additional concomitant procedures, such as anterior vitrectomy, lens implantation or exchange, and drainage tube implantation.

CONCLUSIONS

Combined penetrating keratoplasty and trabeculectomy with mitomycin C is associated with good corneal graft survival but also a risk of early failure of intraocular pressure control. Other concomitant procedures during the combined penetrating keratoplasty/trabeculectomy may increase the risk of early bleb failure.

Intracameral urokinase for dissolution of fibrin or blood clots after glaucoma surgery

PURPOSE

To report the use of intracameral urokinase for dissolving fibrin or blood clots after glaucoma surgery.

METHODS

Four eyes of four patients who had undergone glaucoma surgery developed an anterior chamber fibrin or blood clot and increased intraocular pressure. Urokinase was injected into the anterior chamber in each patient to dissolve the clot.

RESULTS

In all cases, urokinase injection resulted in reduction of intraocular pressure. No adverse effects of urokinase injection were detected during the short follow-up period.

CONCLUSIONS

Urokinase may be a safe, inexpensive, and convenient alternative to tissue plasminogen activator for dissolving fibrin or blood clots after glaucoma surgery. Additional studies are warranted to evaluate the long-term safety of intracameral injection.

Comparison of visual function in fellow eyes after bilateral nonarteritic anterior ischemic optic neuropathy

PURPOSE

Although previous studies have examined the risk of bilaterality of nonarteritic ischemic optic neuropathy (NAION), none have compared extensively the extent of visual loss between fellow eyes. The authors examined cases of bilateral NAION to determine the extent of vision loss in the second eye compared with that in the first eye.

METHODS

Thirty-one cases of bilateral NAION were reviewed. Variables included age, gender, and the presence of comorbid disease. Visual function was assessed by Snellen visual acuity, color vision, and pattern and mean deviation of the visual fields.

RESULTS

No correlation was detected between the extent or pattern of visual loss in fellow eyes. No significant difference in visual function existed between first and second eyes for the patients overall. Patients who retained better visual function in the second eye were significantly older than those who retained better visual function in the first eye (visual acuity, P = 0.0005; color vision, P = 0.07; mean deviation, P = 0.02). In patients older than 50 years of age (25 of 31 cases), the second eye had significantly better visual acuity (P = 0.04) and less Humphrey visual field mean deviation (P = 0.04) than the first eye.

CONCLUSION

Visual function in the second eye correlated poorly with that of the first eye. Older patients with bilateral NAION retained better visual function in the second eye than in the first eye. For younger patients, the extent of visual loss in the second eye could not be predicted based on the visual loss in the first eye.

Genetic heterogeneity in Hispanic families with autosomal dominant juvenile glaucoma

A gene for autosomal dominant, juvenile-onset, primary open angle glaucoma (GLCIA) has been previously mapped to 1q21-31 in several Caucasian pedigrees. We studied two Hispanic families with this disease to determine if their disease genes also map to this region. Individuals were considered as being affected if they had 1OP > 30 mmHg (without treatment) and glaucomatous optic nerve damage or visual field defects. Persons older than 40 years with intraocular pressures < or = 21 mmHg and no evidence of optic nerve damage or visual field loss were scored as unaffected. Individuals not falling into these two categories were considered unknown. Genomic DNA was extracted from blood samples and subjected to PCR-based microsatellite marker analysis. Computer-based linkage analysis was used to determine if the disease gene mapped to chromosome 1q2I-31. In the family from the Canary Islands, the disease gene was linked to the chromosome 1q2I-31 region previously identified by other researchers. Markers D1S212 and D1S218 produced maximum lod scores of 3.38 and 2.99, respectively. In the family from the Balearic Islands, the disease gene was excluded from this region by genetic linkage analysis. Haplotype analysis also excluded the disease gene from chromosome 1q21-31. Our Hispanic families showed genetic heterogeneity with respect to autosomal dominant, juvenile-onset, primary open angle glaucoma.

Cell surface receptors for herpes simplex virus are heparan sulfate proteoglycans

The role of cell surface heparan sulfate in herpes simplex virus (HSV) infection was investigated using CHO cell mutants defective in various aspects of glycosaminoglycan synthesis. Binding of radiolabeled virus to the cells and infection were assessed in mutant and wild-type cells. Virus bound efficiently to wild-type cells and initiated an abortive infection in which immediate-early or alpha viral genes were expressed, despite limited production of late viral proteins and progeny virus. Binding of virus to heparan sulfate-deficient mutant cells was severely impaired and mutant cells were resistant to HSV infection. Intermediate levels of binding and infection were observed for a CHO cell mutant that produced undersulfated heparan sulfate. These results show that heparan sulfate moieties of cell surface proteoglycans serve as receptors for HSV.

Heparan sulfate glycosaminoglycans as primary cell surface receptors for herpes simplex virus

Our current incomplete picture of the earliest events in HSV infection may be summarized as follows. The initial interaction of virus with cells is the binding of virion gC to heparan sulfate moieties of cell surface proteoglycans. Stable binding of virus to cells may require the interaction of other virion glycoproteins with other cell surface receptors as well (including the interaction of gB with heparan sulfate). Penetration of virus into the cell is mediated by fusion of the virion envelope with the cell plasma membrane. Events leading up to this fusion require the action of at least three viral glycoproteins (gB, gD and gH), one or more of which may interact with specific cell surface components. It seems likely that binding of gB to cell surface heparan sulfate may occur and may be important in the activation of some event required for virus penetration. Heparan sulfate is present not only as a constituent of cell surface proteoglycans but also as a component of the extracellular matrix and basement membranes in organized tissues. In addition, body fluids contain both heparin and heparin-binding proteins, either of which can prevent the binding of HSV to cells (WuDunn and Spear, 1989). As a consequence, the spread of HSV infection is probably influenced, not only by immune responses to the virus, but also by the probability that virus will be entrapped or inhibited from binding to cells by extracellular forms of heparin or heparan sulfate.

Glycoprotein C of herpes simplex virus type 1 plays a principal role in the adsorption of virus to cells and in infectivity

The purpose of this study was to identify the herpes simplex virus glycoprotein(s) that mediates the adsorption of virions to cells. Because heparan sulfate moieties of cell surface proteoglycans serve as the receptors for herpes simplex virus adsorption, we tested whether any of the viral glycoproteins could bind to heparin-Sepharose in affinity chromatography experiments. Two glycoproteins, gB and gC, bound to heparin-Sepharose and could be eluted with soluble heparin. In order to determine whether virions devoid of gC or gB were impaired for adsorption, we quantitated the binding of wild-type and mutant virions to cells. We found that at equivalent input concentrations of purified virions, significantly fewer gC-negative virions bound to cells than did wild-type or gB-negative virions. In addition, the gC-negative virions that bound to cells showed a significant delay in penetration compared with wild-type virus. The impairments in adsorption and penetration of the gC-negative virions can account for their reduced PFU/particle ratios, which were found to be about 5 to 10% that of wild-type virions, depending on the host cell. Although gC is dispensable for replication of herpes simplex virus in cell culture, it clearly facilitates virion adsorption and enhances infectivity by about a factor of 10.

Initial interaction of herpes simplex virus with cells is binding to heparan sulfate

We have shown that cell surface heparan sulfate serves as the initial receptor for both serotypes of herpes simplex virus (HSV). We found that virions could bind to heparin, a related glycosaminoglycan, and that heparin blocked virus adsorption. Agents known to bind to cell surface heparan sulfate blocked viral adsorption and infection. Enzymatic digestion of cell surface heparan sulfate but not of dermatan sulfate or chondroitin sulfate concomitantly reduced the binding of virus to the cells and rendered the cells resistant to infection. Although cell surface heparan sulfate was required for infection by HSV types 1 and 2, the two serotypes may bind to heparan sulfate with different affinities or may recognize different structural features of heparan sulfate. Consistent with their broad host ranges, the two HSV serotypes use as primary receptors ubiquitous cell surface components known to participate in interactions with the extracellular matrix and with other cell surfaces.