Effect of surgery on visual field progression in normal-tension glaucoma

Risk Calculation in the Medication Arm of the Ocular Hypertension Treatment Study

PURPOSE

Risk assessment is integral to the management of individuals with ocular hypertension (OHTN). This study aims to determine the predictive accuracy of the Ocular Hypertension Treatment Study 5-year risk calculator (OHTS calculator) among treated patients with OHTN by applying it to patients randomized to the Ocular Hypertension Treatment Study (OHTS) medication arm.

DESIGN

Post hoc secondary analysis of a randomized clinical trial.

SUBJECTS

Individuals participating in the OHTS who were randomized to the medication arm. Only participants with complete baseline data in both eyes were included (n = 726).

METHODS

The hazard ratios (HRs) of the medication group in OHTS were compared to the HR used for the OHTS calculator using the z-test statistic to establish the OHTS calculator's generalizability to the OHTS medication arm. The performance of the OHTS calculator among the OHTS medication group was evaluated twice, using both untreated baseline intraocular pressure (IOP) and average treated IOP during the first 24 months for the IOP variable.

MAIN OUTCOME MEASURES

The performance was determined based on the model's accuracy in estimating the risk of reaching an OHTS primary open-angle glaucoma (POAG) end point using calibration chi-square and discriminating between participants who did or did not develop POAG.

RESULTS

The HRs for the OHTS medication arm were not significantly different from those used in the OHTS calculator for untreated OHTN derived from observation arm data (P > 0.1). Based on the calibration chi-square test for the medication group, the OHTS calculator prediction model had good predictive accuracy when using the mean treated IOP and poorer predictive accuracy with the untreated baseline IOP (chi-square 10 and 29, respectively). The model had good discrimination with treated IOP (c-statistic = 0.77), comparable to what has been reported for the OHTS calculator in the OHTS observation group.

CONCLUSIONS

The OHTS calculator can be applied to treated patients with OHTN, and repeat risk calculation after initiating IOP reduction may provide useful information that can aid in disease management.

FINANCIAL DISCLOSURE(S)

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

FP and EP2 prostanoid receptor agonist drugs and aqueous humor outflow devices for treating ocular hypertension and glaucoma

Prostaglandin (PG) receptors represent important druggable targets due to the many diverse actions of PGs in the body. From an ocular perspective, the discovery, development, and health agency approvals of prostaglandin F (FP) receptor agonists (FPAs) have revolutionized the medical treatment of ocular hypertension (OHT) and glaucoma. FPAs, such as latanoprost, travoprost, bimatoprost, and tafluprost, powerfully lower and control intraocular pressure (IOP), and became first-line therapeutics to treat this leading cause of blindness in the late 1990s to early 2000s. More recently, a latanoprost-nitric oxide (NO) donor conjugate, latanoprostene bunod, and a novel FP/EP3 receptor dual agonist, sepetaprost (ONO-9054 or DE-126), have also demonstrated robust IOP-reducing activity. Moreover, a selective non-PG prostanoid EP2 receptor agonist, omidenepag isopropyl (OMDI), was discovered, characterized, and has been approved in the United States, Japan and several other Asian countries for treating OHT/glaucoma. FPAs primarily enhance uveoscleral (UVSC) outflow of aqueous humor (AQH) to reduce IOP, but cause darkening of the iris and periorbital skin, uneven thickening and elongation of eyelashes, and deepening of the upper eyelid sulcus during chronic treatment. In contrast, OMDI lowers and controls IOP by activation of both the UVSC and trabecular meshwork outflow pathways, and it has a lower propensity to induce the aforementioned FPA-induced ocular side effects. Another means to address OHT is to physically promote the drainage of the AQH from the anterior chamber of the eye of patients with OHT/glaucoma. This has successfully been achieved by the recent approval and introduction of miniature devices into the anterior chamber by minimally invasive glaucoma surgeries. This review covers the three major aspects mentioned above to highlight the etiology of OHT/glaucoma, and the pharmacotherapeutics and devices that can be used to combat this blinding ocular disease.

Degeneration of retina-brain components and connections in glaucoma: Disease causation and treatment options for eyesight preservation

Eyesight is the most important of our sensory systems for optimal daily activities and overall survival. Patients who experience visual impairment due to elevated intraocular pressure (IOP) are often those afflicted with primary open-angle glaucoma (POAG) which slowly robs them of their vision unless treatment is administered soon after diagnosis. The hallmark features of POAG and other forms of glaucoma are damaged optic nerve, retinal ganglion cell (RGC) loss and atrophied RGC axons connecting to various brain regions associated with receipt of visual input from the eyes and eventual decoding and perception of images in the visual cortex. Even though increased IOP is the major risk factor for POAG, the disease is caused by many injurious chemicals and events that progress slowly within all components of the eye-brain visual axis. Lowering of IOP mitigates the damage to some extent with existing drugs, surgical and device implantation therapeutic interventions. However, since multifactorial degenerative processes occur during aging and with glaucomatous optic neuropathy, different forms of neuroprotective, nutraceutical and electroceutical regenerative and revitalizing agents and processes are being considered to combat these eye-brain disorders. These aspects form the basis of this short review article.

Therapeutic Drugs and Devices for Tackling Ocular Hypertension and Glaucoma, and Need for Neuroprotection and Cytoprotective Therapies

Damage to the optic nerve and the death of associated retinal ganglion cells (RGCs) by elevated intraocular pressure (IOP), also known as glaucoma, is responsible for visual impairment and blindness in millions of people worldwide. The ocular hypertension (OHT) and the deleterious mechanical forces it exerts at the back of the eye, at the level of the optic nerve head/optic disc and lamina cribosa, is the only modifiable risk factor associated with glaucoma that can be treated. The elevated IOP occurs due to the inability of accumulated aqueous humor (AQH) to egress from the anterior chamber of the eye due to occlusion of the major outflow pathway, the trabecular meshwork (TM) and Schlemm’s canal (SC). Several different classes of pharmaceutical agents, surgical techniques and implantable devices have been developed to lower and control IOP. First-line drugs to promote AQH outflow via the uveoscleral outflow pathway include FP-receptor prostaglandin (PG) agonists (e.g., latanoprost, travoprost and tafluprost) and a novel non-PG EP2-receptor agonist (omidenepag isopropyl, Eybelis^®). TM/SC outflow enhancing drugs are also effective ocular hypotensive agents (e.g., rho kinase inhibitors like ripasudil and netarsudil; and latanoprostene bunod, a conjugate of a nitric oxide donor and latanoprost). One of the most effective anterior chamber AQH microshunt devices is the Preserflo^® microshunt which can lower IOP down to 10–13 mmHg. Other IOP-lowering drugs and devices on the horizon will be also discussed. Additionally, since elevated IOP is only one of many risk factors for development of glaucomatous optic neuropathy, a treatise of the role of inflammatory neurodegeneration of the optic nerve and retinal ganglion cells and appropriate neuroprotective strategies to mitigate this disease will also be reviewed and discussed.

Improved Detection of Visual Field Progression Using a Spatiotemporal Boundary Detection Method

Glaucoma is the leading cause of irreversible blindness worldwide and requires regular monitoring upon diagnosis to ascertain whether the disease is stable or progressing. However, making this determination remains a difficult clinical task. Recently, a novel spatiotemporal boundary detection predictor of glaucomatous visual field (VF) progression (STBound) was developed. In this work, we explore the ability of STBound to differentiate progressing and non-progressing glaucoma patients in comparison to existing methods. STBound, Spatial PROGgression, and traditional trend-based progression methods (global index (GI) regression, mean regression slope, point-wise linear regression, permutation of pointwise linear regression) were applied to longitudinal VF data from 191 eyes of 91 glaucoma patients. The ability of each method to identify progression was compared using Akaike information criterion (AIC), full/partial area under the receiver operating characteristic curve (AUC/pAUC), sensitivity, and specificity. STBound offered improved diagnostic ability (AIC: 197.77 vs. 204.11-217.55; AUC: 0.74 vs. 0.63-0.70) and showed no correlation (r: -0.01-0.11; p-values: 0.11-0.93) with the competing methods. STBound combined with GI (the top performing competitor) provided improved performance over all individual metrics and compared to all metrics combined with GI (all p-values < 0.05). STBound may be a valuable diagnostic tool and can be used in conjunction with existing methods.

Impact of Intraocular Pressure after Filtration Surgery on Visual Field Progression in Primary Open-Angle Glaucoma

PURPOSE

To compare visual field progression after trabeculectomy in eyes showing a postoperative intraocular pressure (IOP) less than or equal to 16 mmHg and eyes with an IOP of 17 to 21 mmHg.

METHODS

A retrospective cohort study design was used. A total of 101 eyes of 101 consecutive patients undergoing trabeculectomy for primary open-angle glaucoma (POAG) with a postoperative IOP less than or equal to 21 mmHg were divided into two groups: Group 1 included eyes showing a postoperative IOP less than or equal to 16 mmHg at all visits and Group 2 included eyes with a postoperative IOP between 17 and 21 mmHg. In turn, each of these groups was divided into two subgroups according to whether treatment was required for IOP control. Glaucomatous visual field control during follow-up was compared between the subject groups.

RESULTS

Kaplan-Meier analysis revealed glaucomatous visual field control in 98.53% of the eyes in Group 1 and 89.06% of those in Group 2 at 5 years, the difference between the groups being significant.

CONCLUSIONS

Glaucomatous disease progression is less frequent when IOP is less than or equal to 16 mmHg in all the follow-up visits after trabeculectomy. The results indicate a definite benefit of low IOP in visual field control.

Effect of Brimonidine on Intraocular Pressure in Normal Tension Glaucoma: A Short Term Clinical Trial

Purpose

To evaluate the efficacy and safety of 0.2% brimonidine eye drops given twice daily in normal tension glaucoma.

Patients and Methods

Sixteen consecutive patients fulfilling eligibility criteria (glaucomatous optic neuropathy associated with visual field defect in at least one eye, intraocular pressure (IOP) = 18 mmHg (average of the two highest readings of the round-the-clock curve, including one reading at midnight in supine position), no prior glaucoma therapy, angle wide open, visual acuity 20/40 or better) were enrolled in this prospective, randomized, placebo-controlled clinical trial with crossover design, lasting 30 days for each treatment phase plus 15-day washout in between. Main outcome was IOP (average of the two highest readings of the round-the-clock curve).

Results

Mean IOP was significantly reduced by brimonidine (from 17.1 ± 0.7 mm Hg to 13.9 ± 2.2 mmHg, p<0.001 (paired Student t-test)). At the end of the 30-day brimonidine phase, 4 of 16 subjects showed a ≥30% IOP decrease over baseline.

Conclusions

In the short term, 0.2% brimonidine eye drops can induce a significant IOP decrease in eyes with normal tension glaucoma.

Effect of primary Phacoviscocanalostomy/ Viscocanalostomy on intraocular pressure of normal tension glaucoma patients: 3-year results

BACKGROUND

The objective of this study was to evaluate the efficacy of Viscocanalostomy/Phacoviscocanalostomy (VC/PVC) in lowering intraocular pressure (IOP) in Normal Tension Glaucoma (NTG) patients.

METHODS

Retrospective electronic database review of patients who underwent VC/PVC for NTG between December 2009 and November 2011 at Stanley eye unit in Abergele Hospital. Goldmann applanation tonometry (GAT) was used for all IOP measurements which were taken at the time of listing for surgery and at 1 day, 1 week, 1 month, then 3-monthly up to 1 year, then half-yearly up to 3 years post operatively. Statistical analysis was performed using unpaired t-test. A P value of <0.05 was accepted as the level of significance.

RESULTS

Operations were performed on 94 eyes from 67 patients over the study period. The mean age at the time of surgery was 76.4 years. Pre-operative IOP was 17.75 ± 2.19 mmHg (range 12-21 mmHg). 3 year follow-up showed a mean IOP of 13.41 ± 2.22 mmHg (range 8-18 mmHg). By year 3, 17 patients needed laser goniopuncture and 25 patients needed antiglaucoma drops. IOP was reduced by 24.4% at 3 years post-surgery, which was statistically significant (p < 0.0001).

CONCLUSIONS

From our results, which show a 24.5% reduction in IOP at 3 years with 12% complication rate, we propose that a logical surgical management for NTG patients would be viscocanalostomy, thereby keeping trabeculectomy as an alternative.

Effectiveness of Single-Digit IOP Targets on Decreasing Global and Localized Visual Field Progression After Filtration Surgery in Eyes With Progressive Normal-Tension Glaucoma

PURPOSE

To examine the effectiveness of achieving single-digit intraocular pressure (IOP) targets with filtration surgery on decreasing global and localized visual field (VF) progression in eyes with progressive normal-tension glaucoma (NTG).

METHODS

A retrospective chart review was conducted to identify NTG patients who underwent trabeculectomy with mitomycin C between 2006 and 2010 for progressive VF loss with preoperative IOP≤15 mm Hg during the 12 months before surgery. All eyes had glaucomatous optic neuropathy and progressive VF loss, uncontrolled IOP on maximum therapy, and a minimum of 2 baseline preoperative and 4 postoperative VF examinations. VF progression was assessed using Guided Progression Analysis (GPA) and Progressor software.

RESULTS

Fifteen eyes of 14 patients (mean age 71.8±7.5 y) were enrolled with mean follow-up of 71±26 months. Mean postoperative IOP (8.5±3.5 mm Hg) was significantly (P<0.001) reduced compared with preoperatively (13.1±1.5 mm Hg). The probability of achieving an IOP goal ≤10 mm Hg was 66% at 4 years' follow-up. The overall rate of postoperative VF progression using any method was 13.3% (1 eye using Progressor; 1 eye using GPA and Progressor). Average postoperative slope of MD (-0.25±0.86 dB/y) and pattern SD (0.49±0.83 dB/y) were improved (P=0.05 and 0.07) compared with the preoperative slopes (-1.05±0.66 and 1.21±0.71 dB/y).

CONCLUSIONS

Achieving single-digit IOP targets with filtration surgery has a beneficial effect on reducing global and localized rates of VF progression in NTG eyes with progression at low IOP.

Effect of trabeculectomy on visual field progression in Japanese progressive normal-tension glaucoma with intraocular pressure < 15 mmHg

We examined the effectiveness of trabeculectomy in decreasing the slope of mean deviation (MD) in Japanese patients with progressive normal-tension glaucoma (NTG) at low intraocular pressure (IOP) levels. The charts of patients who had undergone initial trabeculectomy with adjunctive mitomycin C for progressive NTG with medically controlled IOP < 15 mmHg in 2010–2013 were retrospectively reviewed. Seventeen eyes of 13 NTG patients who had undergone at least 5 times of visual field (VF) examinations in both of preoperatively and postoperatively with postoperative follow-up of ≥ 2 years were enrolled. Preoperative and postoperative MD slopes were compared to evaluate the effectiveness of trabeculectomy in slowing progression of VF. Mean IOP (8.1 ± 2.9 mmHg) and number of IOP-lowering medications (0.8 ± 1.5) were significantly lower postoperatively than preoperatively (13.9 ± 0.9 mmHg; P < 0.001 and 3.0± 0.4; P < 0.0001). In total, 91.7% of eyes with single-digit IOP postoperatively showed improvement in MD slope, whereas only 20.0% of eyes with IOP ≥ 10 mmHg postoperatively showed the improvement. Three eyes (17.6%) showed a decrease in visual acuity (VA) of ≥ 0.1 unit; this group had a lower mean postoperative IOP (6.0 ± 1.0 vs. 8.6 ± 3.0 mmHg; P = 0.1717) and a higher mean IOP reduction rate (56.2 vs. 38.5%; P = 0.8296) than eyes with a VA decrease of < 0.1 unit or no change. Thus, in this analysis of Japanese NTG patients with medically controlled IOP < 15 mmHg, achieving an IOP < 10 mmHg with trabeculectomy was beneficial for reducing the VF progression rate in progressive NTG at low IOP levels. However, an IOP < 7 mmHg by surgery would be required careful attention to VA decline.

Difference in glaucoma progression between the first and second eye after consecutive bilateral glaucoma surgery in patients with bilateral uveitic glaucoma

PURPOSE

To determine whether the second eyes (SE) of patients with bilateral uveitic glaucoma undergoing filtration surgery have more glaucomatous progression in terms of visual acuity, visual field (VF) and optic nerve changes compared to the first eyes (FE).

METHODS

This retrospective study analysed data of 60 eyes from 30 patients with bilateral uveitic glaucoma who had undergone glaucoma surgery in both eyes on separate occasions. Humphrey VF progression was assessed using the Progressor software.

RESULTS

The pre-operative IOP between the FE (43.1 ± 7.7 mmHg) and SE (40 ± 8.7 mmHg) was not statistically significant (p = 0.15). IOP reduction was greater in the FE (64 %) than SE (59.7 %) post-operatively, but the mean IOP at the final visit in the FE (12.3 ± 3.9 mmHg) and SE (14.5 ± 7 mmHg) was not statistically different (p = 0.2). There was no significant change in mean logMAR readings pre and post-operatively (0.45 ± 0.6 vs 0.37 ± 0.6, p = 0.4) or between the FE and SE. The number of SE with CDR > 0.7 increased by 23 % compared to the FE. From 23 available VFs, five SE (21.7 %) progressed at a median of five locations (range 1-11 points) with a mean local slope reduction of 1.74 ± 0.45 dB/year (range -2.39 to -1.26), whereas only one FE progressed. However, there was no significant difference between mean global rate of progression between the FE (-0.9 ± 1.6 dB/year) and SE (-0.76 ± 2.1 dB/year, p = 0.17) in the Humphrey VF.

CONCLUSION

In eyes with bilateral uveitic glaucoma requiring glaucoma surgery, the SEs had more progressed points on VF and glaucomatous disc progression compared to FEs at the final visit.

[Current aspects on the management of normal tension glaucoma]

In a considerable proportion of glaucoma patients (25-50 %) the intraocular pressure (IOP) is not elevated higher than 22 mmHg at first diagnosis and during subsequent follow-up controls. Although the IOP level remains in the low range < 22 mmHg, progression of glaucoma can still occur. A multitude of different factors are assumed to be involved in glaucoma progression, such as very low nocturnal diastolic blood pressure values, a low mean ocular perfusion pressure, extensive fluctuations in perfusion (e.g. in cases of vascular dysregulation), an increased vulnerability of the optic nerve support structures, an increased translaminar pressure gradient and various underlying systemic diseases. The most important evidence-based aspect of treatment in normal tension glaucoma is pharmaceutical or surgical reduction of the IOP by 30 % or more in comparison to the initial pressure level. Vascular and neuroprotective concepts of treatment for normal tension glaucoma have been strongly advocated and the object of experimental and clinical studies. As yet a clear clinical benefit has not been proven by large prospective randomized studies.

Advance in the pathogenesis and treatment of normal-tension glaucoma

Normal-tension glaucoma (NTG) is a multifactorial disease where mechanical stresses and vascular alterations to the optic nerve head probably represent the key pathogenic moments. Although intraocular pressure (IOP) plays a crucial role in the retinal ganglion cell loss, the IOP reduction does not necessarily reduces the disease progression. Therefore, several IOP-independent factors such as glutamate toxicity, oxidative stress, autoimmunity, and vascular dysregulation have been considered in the pathogenesis of NTG. Numerous evidences documented an impairment of the ocular blood flow, involved both in the onset and progression of the disease. The IOP reduction remains the main strategy to reduce the damage progression in NTG. Recently, new treatment strategies have been proposed to improve the control of the disease. Neuroprotection is a rapidly expanding area of research, which represents a promising tool. In the present review, we summarize the recent scientific advancements in the pathogenesis and treatment of NTG.

Targeted spatial sampling using GOANNA improves detection of visual field progression

PURPOSE

A new automated visual field testing approach that samples scotoma edges at a finer spatial resolution, GOANNA (Gradient-Oriented Automated Natural Neighbour Approach) was previously shown to improve accuracy and precision around those regions compared to current procedures in computer simulation. The purpose of this study was to observe if this improvement translated to more accurate classification of glaucomatous progression.

METHODS

Computer simulations were undertaken on six procedures: three variants of GOANNA on 150 locations; two variants of ZEST on 52 locations; and the ideal case where true thresholds are perfectly measured. The median number of presentations of GOANNA was matched to ZEST. The procedures were run on 156 sequences of simulated progressing fields and 156 sequences of stable fields to determine sensitivity and specificity using point-wise linear regression. Reliable (0% FP, 0% FN) and typical false positive (15% FP, 3% FN) response error conditions were investigated. Area under ROC curves (AUC) were plotted against the number of visual fields acquired to evaluate the performance of these procedures.

RESULTS

The GOANNA framework exhibited equal or greater AUC than ZEST at all visits when baseline fields were initially defective (under both response error conditions) and when baseline fields were initially healthy when no false responses were made. Retest implementations of GOANNA exhibited an improvement over the original GOANNA after the first seven visits when fields were initially healthy.

CONCLUSION

The results suggest that the improvement in precision and accuracy around scotoma borders seen in the GOANNA framework translates to earlier and more accurate detection of progressing fields compared with ZEST, especially in the early stages of glaucomatous progression.

Visual Field Progressive Rate in Normal Tension Glaucoma Before and After Trabeculectomy: A Subfield-Based Analysis

PURPOSE

To compare pretrabeculectomy and posttrabeculectomy progression rates in normal-tension glaucoma in 6 subfields of the central 30 visual field.

DESIGN

A retrospective study.

METHODS

Clinical records of 34 patients with normal-tension glaucoma (12 males and 22 females) with progressive visual field loss undergoing successful trabeculectomy were studied. The time course of the mean deviation (MD) and mean of total deviation in the superior/inferior arcuate, paracentral, and cecocentral subfields were analyzed using a linear mixed-effects model.

RESULTS

Patients' age, intraocular pressure (IOP), MD, and pretrabeculectomy and posttrabeculectomy follow-up averaged 57.7 ± 9.6 years, 15.7 ± 1.7 mm Hg, -12.7 ± 5.5 dB, and 4.6 ± 1.5 and 5.7 ± 1.2 years, respectively. Average IOP was lowered by 6.1 ± 3.3 to 10.3 ± 2.7 mm Hg (5-14 mm Hg) over the postoprerative period with MD change rate of -0.25 dB/y (P < 0.003), which was slower (P < 0.001) than the preoperative one (-0.70 dB/y). The preoperative mean of total deviation change rate (-0.31 to -1.35 dB/y) improved postoperatively in the superior and inferior paracentral subfields (P < 0.001), whereas it remained unchanged in the inferior cecocentral/arcuate subfields (P > 0.10). The postoperative rate of progression showed no significant variation in these subfields.

CONCLUSIONS

The rate of progression significantly varied among the 6 subfields preoperatively. It was significantly slowed down in the superior subfields by surgical IOP reduction, but not in the inferior cecocentral/arcuate subfields.

Surgical Decisions in Primary Open Angle Glaucoma with Low or Normal Tension

Glaucoma, given its insidious nature, is often coined 'the sneak thief of sight'. Following this trail of thought, primary open angle glaucoma with low or normal tension (POAGLNT) could be coined 'the king of thieves'. The lack of a compelling red fag of high intraocular pressure (IOP), together with the diurnal fuctuation of the deceptively low baseline IOP, POAGLNT poses a therapeutic challenge in terms of judging when to intervene, and how. In this review article, we will outline the considerations before undergoing surgery: risk stratification, defining goal in terms of target pressure and IOP modulation. We will also review the strengths, weaknesses and pearls of available options. How to cite this article: Shum JW, Leung DY. Surgical Decisions in Primary Open Angle Glaucoma with Low or Normal Tension. J Current Glau Prac 2013;7(3):121-127.

Effect of trabeculectomy on retrobulbar circulation and visual field progression in patients with primary open-angle glaucoma

Background

The purpose of this study was to investigate the relationship between retrobulbar circulation and visual field change in eyes with primary open-angle glaucoma following unilateral trabeculectomy.

Methods

Twenty-one patients with primary open-angle glaucoma were prospectively enrolled. Retrobulbar circulation was evaluated using color Doppler imaging. The peak systolic velocity, end-diastolic velocity, and resistive index were evaluated in the central retinal artery, temporal site of the short posterior ciliary artery (t-SPCA), and nasal site of the short posterior ciliary artery (n-SPCA). Visual field examinations were performed using a Humphrey visual field analyzer before surgery and trimonthly for 12 months postoperatively.

Results

In the operative eyes, the end-diastolic velocity was significantly increased in the central retinal artery (P = 0.005, analysis of variance), t-SPCA (P = 0.005), and n-SPCA (P = 0.027). The resistive index was significantly decreased in the central retinal artery (P = 0.003), t-SPCA (P = 0.000), and n-SPCA (P = 0.010) postoperatively compared with preoperatively. The nonoperative contralateral eyes did not show a significant change in end-diastolic velocity or resistive index for either the SPCA or central retinal artery. The mean deviation slope in the operative eyes (−0.26 ± 0.64 dB/year) was significantly slower than that in the nonoperative eyes (−0.65 ± 0.70 dB/year; P = 0.047, Mann-Whitney U test).

Conclusion

These results suggest that trabeculectomy improves the retrobulbar circulation and prevents the progression of visual field changes in patients with primary open-angle glaucoma.

The evidence base to select a method for assessing glaucomatous visual field progression

A large number of methods have been developed for assessing glaucomatous visual field progression, but their properties have not yet been systematically evaluated. In this systematic literature review, we summarize the evidence base for selecting a method by providing answers to ten relevant questions on the variety, validity and reproducibility of methods. In total, we found 301 different methods in 412 articles. The majority of studies (54%) used the Humphrey Field Analyzer. No data have been published about the reproducibility of methods. Although there is no gold standard to assess glaucomatous visual field progression, we found evidence on validity for 48 different methods. Some methods were less capable of distinguishing between progressive and nonprogressive patients. Choosing among twelve methods is supported by some evidence of their validity. These methods still differ in sensitivity, specificity and predictive values of test results within studies comparing several methods. In conclusion, the current evidence base is not perfect. A selection should be made from a limited number of methods, according to the clinical purpose of progression assessment. Methods that quantify the rate of visual field progression seem to be the most appropriate for guiding subsequent medical actions in individual patients. Future studies should investigate whether using one method to monitor patients is superior to another method in preventing loss of quality of life.

Target intraocular pressure for stability of visual field loss progression in normal-tension glaucoma

PURPOSE

To determine the target intraocular pressure (IOP) level in normal-tension glaucoma (NTG) for visual field (VF) stability following trabeculectomy.

METHODS

Forty eyes of 40 patients who underwent trabeculectomy were enrolled in this study. Progression was determined by a decrease in the Advanced Glaucoma Intervention Study VF defect score of four or more points. The Kaplan-Meier life table method was employed to compare the postoperative VF stability with predetermined IOP levels.

RESULTS

The mean postoperative follow-up period was 12 years. At the final visit, the IOP was reduced from 15.2 to 9.4 mmHg on average (P < 0.0001). Reductions in IOP of 20% from baseline were achieved in 70.0% of eyes. The cumulative probability of VF stability was 92.7% in patients having an IOP reduction of >20%, whereas all patients in the poorly controlled IOP group showed progression (P < 0.0001). When IOP values of 9, 10, 11, and 12 mmHg were employed as the cutoff, the best VF prognosis was attained in eyes with a postoperative IOP of 10 mmHg.

CONCLUSIONS

An IOP reduction of at least 20% from baseline or IOP <or=10 mmHg is recommended as the target postoperative IOP in progressive NTG.

Glaucoma surgery decreases the rates of localized and global visual field progression

PURPOSE

Incisional glaucoma surgical procedures produce greater intraocular pressure (IOP) reduction and less IOP variability than medical treatment. We sought to determine the efficacy of glaucoma surgery in decreasing localized and global rates of visual field (VF) progression.

DESIGN

Retrospective, interventional case series.

METHODS

Subjects in the New York Glaucoma Progression Study with glaucomatous optic neuropathy, repeatable VF loss, and 10 or more Swedish interactive threshold algorithm standard VF examinations were assessed for eligibility. Patients who underwent successful glaucoma surgery (not requiring further surgical intervention and IOP < 18 mm Hg) in either eye and who were followed up for at least 2 years before and after surgery were enrolled. Automated pointwise linear regression analysis was used to calculate global and localized rates of progression before and after surgery. Eyes with other ocular conditions likely to affect the VF and an insufficient number of VF to create a slope before and after surgery were excluded. Comparisons were performed within the same eyes before and after surgery (Student paired t test).

RESULTS

We enrolled 28 eyes of 28 patients (mean age, 61.2 +/- 14.5 years). The mean number +/- standard deviation of VF was 13.4 +/- 2.3, spanning 7.1 +/- 1.2 years (range, 4 to 9 years). Mean IOP +/- standard deviation decreased from 19.0 +/- 3.9 mm Hg before surgery to 11.3 +/- 3.7 mm Hg after surgery (40% reduction; P < .01). Mean global progression rates decreased from -1.48 +/- 1.4 dB/year before surgery to -0.43 +/- 0.8 dB/year after surgery (70% reduction; P = .01). Twelve eyes (42.8%) had at least 1 significantly progressing point before surgery, whereas only 2 (7.1%) had at least 1 progressing point after surgery. Each 1 mm Hg of IOP reduction after surgery resulted in a 0.1 dB/year decrease in the global rate of progression.

CONCLUSIONS

Successful IOP reduction after glaucoma surgery greatly reduces both the number of progressing points and the localized and general rates of VF progression.

Glaucoma: an area of darkness

This review of Primary Open Angle Glaucoma looks at the management of the condition today. It does this by looking at the following areas: (a) the size of the problem; (b) the position of IOP, with respect to its elevation and fluctuation; (c) optic nerve head changes; and (d) visual function changes. In doing so, it contrasts what is known now with ideas and concepts that were prevalent at the time of the two previous Bowman lecturers, Duke Elder and Drance, as well as noting concepts about the disease that were current at the time of William Bowman. The review concludes by suggesting challenges in this area that lie ahead.

Pointwise linear progression criteria and the detection of visual field change in a glaucoma trial

BACKGROUND

Current pointwise linear regression (PLR) change criteria for visual field analysis are largely empirical.

METHODS

Two independent sets of Humphrey Field Analyzer fields were analysed using PLR. Set i, 56 patients, and set ii, 97 patients, were followed over 16 months. Criteria were tested against set i, and then validated using set ii. Each criterion specified a fixed critical slope of 1 dB/year and with a range of significance from P<0.001 to 0.05. The criteria were varied by altering location number, cluster arrangement, and by requiring points to show change over both 12 and 16 months. True glaucomatous change was differentiated from noise by looking for exclusive progression (EP), the detection of progression without detection of improvement.

RESULTS

Set i required 1 point to have a slope of 1 dB/year and P<0.05 labelled 64% progressing and 58% improving, whereas several stricter criteria were capable of detecting EP. Two points in a perimetric nerve fibre bundle (PNFB) cluster gave optimal EP detection, labelling 8.9% progressing in set i and 7.2% progressing in set ii with a cutoff P-value of 0.026 inset i and 0.013 inset ii.

CONCLUSION

Lax PLR criteria detect large amounts of change. Validating criteria using two data sets allow selection of better criteria, capable of detecting EP. The criterion involving 2 points changing in a PNFB cluster offers the best option for exclusively detecting progression.

Prognostic factors for progression of visual field damage in patients with normal-tension glaucoma

PURPOSE

To evaluate the rate of progression and the prognostic factors of visual field damage in patients with normal-tension glaucoma (NTG).

METHODS

Ninety-two NTG patients (92 eyes) were followed up for more than 2 years with topical antiglaucoma medications. All subjects were classified as having early damaged eyes with an initial mean deviation (MD) of -6 dB or better, moderately damaged eyes with MD between -6 dB and -12 dB, and severely damaged eyes with MD of -12 dB or worse, and survival data were analyzed using regression analysis based on the Cox proportional hazards model.

RESULTS

The probability of visual field stability was significantly higher in patients with moderate damage than in those with severe damage (P = 0.035). The patients with early damage showed no difference in the probability of visual field stability compared with patients with moderate or severe damage. The progression of visual field damage was significantly associated with mean intraocular pressure (IOP) (P = 0.000) or IOP fluctuation (P = 0.002) during follow-up regardless of the severity of the initial visual field damage.

CONCLUSIONS

The rate of progression of visual field damage differed according to the severity of the initial visual field damage. IOP reductive medication may be effective in preventing glaucomatous visual field progression in patients with NTG.

Latanoprost Nonresponders with Open-Angle Glaucoma in the Japanese Population

PURPOSE

As some patients show little response to latanoprost, one of the most powerful topical glaucoma medications, we investigated the incidence and clinical profiles of latanoprost nonresponders (LNR) in the Japanese population.

METHODS

We examined 62 glaucoma patients (62 eyes) who had received only latanoprost for more than 3 months. Their mean age was 63.8 +/- 1.8 years; the mean observation period was 9.7 +/- 0.4 months. At 1, 3, 6, and 12 months, their intraocular pressure (IOP) was measured, and the IOP reduction rate (RR) and the rate of LNR, defined as RR of 10% or less, were calculated. We statistically analyzed clinical factors involved in the LNR status of our study population.

RESULTS

At 1, 3, 6, and 12 months, RR was 20.1 +/- 2.0%, 18.8 +/- 2.3%, 21.1 +/- 2.8%, and 23.0 +/- 2.6%, respectively. At the same time points, the LNR incidence was 23.1%, 28.1%, 23.5%, and 31.8%, respectively, and significantly higher in patients whose baseline IOP was less than 15 mmHg. Patient sex and age and the glaucoma type played no significant role in the LNR status.

CONCLUSIONS

The incidence of LNR in the Japanese population, including normal-tension glaucoma (NTG) patients, is higher than among European or American patients. Only low baseline IOP was a significant clinical factor among LNR.

The effect of latanoprost on intraocular pressure during 12 months of treatment for normal-tension glaucoma

PURPOSE

To evaluate the intraocular pressure (IOP)-lowering efficacy of latanoprost in normal-tension glaucoma (NTG).

METHODS

One-hundred and seventeen eyes of 63 NTG patients treated with 0.005% latanoprost once a day were enrolled in this study. Of these, 85 eyes of 47 patients were treated for 12 months. Mean IOPs were analyzed, and the mean IOP reductions from the untreated baseline were assessed after two weeks and after 1, 3, 6, 9, and 12 months of treatment.

RESULTS

The mean untreated baseline IOP was 15.0 +/- 2.7 mmHg. After two weeks of latanoprost treatment, the mean IOP reduction from the baseline value was 2.6 +/- 0.2 mmHg (17.3%, p<0.05), and after 6 and 12 months, the reduction was 2.4 +/- 0.2 mmHg (16.0%, p<0.05) and 2.4 +/- 0.2 mmHg (16.0%, p<0.05), respectively. Patients with a baseline IOP of > or = 15 mmHg achieved significantly higher IOP reductions than those with a baseline IOP of <15 mmHg at all follow-ups (p<0.05).

CONCLUSIONS

Latanoprost was found to be well tolerated and to significantly reduce IOP in NTG patients.

Therapeutic Strategies for Normal-Tension Glaucoma

Treatment of normal-tension glaucoma has been a subject of debate for several years. Glaucomatous damage cannot be influenced directly, and current treatment modalities in normal-tension glaucoma are aimed at the control of risk factors. Intraocular pressure is a widely accepted risk factor and its reduction can improve the prognosis in normal-tension glaucoma patients. The repeated demonstration of the importance of hemodynamic factors in normal-tension glaucoma has, however, not been paralleled by a comparable progress in the development of therapeutic modalities capable of influencing favorably ocular blood flow. Today, calcium channel blockers seem to be the most promising adjunctive treatment to be considered in patients with glaucomatous optic neuropathy without increased intraocular pressure.

Sequential Office Pressure Measurements in the Management of Glaucoma

PURPOSE

To evaluate the usefulness of day-long sequential office measurements of intraocular pressure (IOP) to make therapeutic decisions in patients with progressive glaucomatous damage despite apparently 'controlled' IOP.

METHODS

We reviewed the records of 93 consecutive glaucoma patients (185 eyes) who underwent sequential office IOP measurements (every hour from 7 AM to 5 PM on a single day). These included 53 patients with normal-tension glaucoma (NTG), 12 glaucoma suspects (GS), and 28 patients with primary open-angle glaucoma (POAG) whose visual field deteriorated despite apparently 'controlled' IOP. Only one eye per patient was included in the study.

RESULTS

The pattern of the day-long IOP curve was similar in the 3 groups of patients. IOPs were highest in the early morning hours in all groups. The mean +/- SD of the IOP range was 5 +/- 2 mm Hg. An IOP > 21 mm Hg was found in 3 eyes (3%), whereas a range of IOPs > 5 mm Hg was detected in 33 eyes (35%). In the NTG group, there was a significant correlation between visual field deterioration and the peak and range of IOP (P = 0.0002 and P = 0.05, respectively).

CONCLUSIONS

Day-long sequential office IOP measurements are useful in selected patients who demonstrate progressive glaucomatous damage. Early morning measurements are most frequently highest. The range of IOP may be as important, or more important than, the peak IOP level.

Advances in glaucoma therapeutics

Glaucoma is a major cause of irreversible blindness in the world. The prevalence of glaucomatous loss in vision will continue to grow as our populations age. Ocular hypertension is a major risk factor for the development of glaucoma and current glaucoma therapy is directed at lowering intraocular pressure. Several new ocular hypotensive agents have been introduced in the past several years providing a variety of treatment options. In addition, various classes of neuroprotective agents demonstrating activity in a wide variety of animal models have been proposed as potential new glaucoma therapeutics. Although these approaches will slow the progression of vision loss, they do not directly intervene in the disease process(es). Advances have been made attempting to understand the pathogenic pathways involved in glaucomatous damage to the eye and in methods to clinically measure glaucoma damage. An increased understanding of the pathophysiology of glaucoma will lead to the development of new therapeutic agents that intervene and perhaps even reverse glaucomatous damage to the eye. There also is a need to develop new methods to clinically measure glaucoma damage because, currently, considerable damage occurs before glaucoma is diagnosed and glaucoma remains underdiagnosed in the general population.

Intraocular pressure and visual field loss in primary angle closure and primary open angle glaucomas

AIM

To compare the correlation between visual field loss and the pretreatment intraocular pressure (IOP) in primary angle closure glaucoma (PACG) and primary open angle glaucoma (POAG).

METHODS

In a cross sectional observational study of 74 patients (43 PACG, 31 POAG), pretreatment IOP was measured at presentation, before treatment was initiated. The severity of visual field loss was assessed by AGIS score, mean deviation (MD), pattern standard deviation (PSD), and corrected pattern standard deviation (CPSD). Glaucomatous optic neuropathy was assessed from simultaneous stereo disc photographs.

RESULTS

There was a stronger correlation between pretreatment IOP and the extent of visual field loss in PACG subjects than in those with POAG for both MD (PACG: Pearson correlation coefficient (r) = 0.43, p = 0.002; r(2) = 0.19), (POAG: r = 0.21, p = 0.13; r(2) = 0.04) and AGIS score (PACG: r = 0.41, p = 0.003; r(2) = 0.17), (POAG: r = 0.23, p = 0.19; r(2) = 0.05 respectively). No such associations were seen for pattern standard deviation (PSD) or corrected pattern standard deviation (CPSD) in either group (p> 0.29). Both horizontal and vertical cup-disc ratio were well correlated with severity of field loss but not with presenting IOP for either diagnosis.

CONCLUSIONS

This is consistent with the hypothesis of a greater IOP dependence for optic nerve damage in PACG than POAG and, conversely, a greater importance of other, less pressure dependent mechanisms in POAG compared to PACG.

Medical treatment of normal tension glaucoma

Normal-tension glaucoma was previously thought to be pressure insensitive, as medical treatment hardly reduced intraocular pressure and it did not prevent visual field loss. In the last decade, however, evidence has shown that the treatment of normal-tension glaucoma by lowering intraocular pressure can slow the deterioration of visual fields, hence the glaucomatous process. It was shown that a reduction of IOP of at least 30% is needed to induce a favorable alteration in the course of normal-tension glaucoma. New agents, such as prostaglandin analogs, the alpha(2)-adrenoceptor agonist brimonidine, and carbonic anhydrase inhibitors, have become available and may be of use in the treatment of normal-tension glaucoma. Monotherapy with prostaglandin analogs may meet the target of a reduction of IOP with 30%, but combination therapy will be needed in many cases. Few studies have been performed with brimonidine, travoprost, and bimatoprost, and it is suggested that more attention should be given to studies with these agents, as about 30% of patients with open angles and glaucomatous visual field defects have normal-tension glaucoma. Although neuroprotection is the goal of the future, no hard data are available yet which demonstrate that treatment with these agents will indeed result in preservation of visual fields.

Long-term follow-up of visual field progression after trabeculectomy in progressive normal-tension glaucoma

OBJECTIVE

To evaluate the long-term effects of trabeculectomy on the progression of visual field damage in patients with progressive normal-tension glaucoma (NTG).

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty-three patients with NTG who had significant progression of visual field damage preoperatively and underwent trabeculectomy using antimetabolites.

METHODS

Visual field testing using the Humphrey Visual Field Analyzer was periodically performed before and for at least 5 years after surgery (mean, 6 years). The time course of the mean deviation (MD) and mean of total deviations (TD(mean)) in four separate subfields, superior and inferior cecocentral and superior and inferior arcuate fields, were analyzed using a linear mixed effects model.

MAIN OUTCOME MEASURES

Intraocular pressure (IOP), preoperative and postoperative regression coefficients of the time course of MD or TD(mean) in the four subfields, corresponding to the rate of progression of visual field damage.

RESULTS

IOP significantly decreased from 16.2 +/- 1.8 mmHg preoperatively to approximately 11 mmHg during the postoperative follow-up period (P < 0.001). The preoperative regression coefficient of MD change was significantly negative (-1.05 [95% confidence interval, -1.28 to -0.82] dB/year, P < 0.001). After surgery, it increased significantly to -0.44 (95% confidence interval, -0.64 to -0.24) dB/year (P < 0.001), but the postoperative value was still significantly negative (P < 0.001). In the superior cecocentral, superior and inferior arcuate fields, preoperative regression coefficients of TD(mean) change were significantly negative (P < 0.001) and significantly increased after surgery (P < 0.01). In the inferior cecocentral field, the preoperative regression coefficient was not significantly different from 0 (P = 0.72) and did not change significantly after surgery (P = 0.15).

CONCLUSIONS

Trabeculectomy was statistically associated with slowing further progression of visual field damage in patients with progressive NTG. The progression, however, did not completely stop over the 6-year postoperative follow-up period.

Optic disc morphology after arteritic anterior ischemic optic neuropathy

OBJECTIVE

To evaluate the appearance of the nerve head in patients after giant cell arteritis-induced arteritic anterior ischemic optic neuropathy (A-AION).

DESIGN

Noncomparative clinical case series.

PATIENTS

The study comprised 29 patients who presented with unilateral A-AION and temporal artery biopsy-proven giant cell arteritis. Stereoscopic optic disc photographs, taken of both the affected and unaffected eyes at the onset of the disease and after a follow-up period of 20.10 +/- 25.36 months (median, 11 months; range, 2-102 months), were morphometrically evaluated.

MAIN OUTCOME MEASURES

Size and shape of the optic disc, neuroretinal rim, optic cup, and alpha and beta zones of parapapillary atrophy.

RESULTS

In the eyes after A-AION, at the end of the study, the neuroretinal rim was significantly (P = 0.002) smaller, and the optic disc cup area was significantly (P = 0.001) larger than those of the contralateral unaffected eyes. Alpha zone and beta zone of parapapillary atrophy did not vary significantly (P > 0.50).

CONCLUSIONS

A-AION, like glaucomatous optic neuropathy, results in neuroretinal rim loss and optic disc cupping. However, in contrast to glaucoma, A-AION is not associated with an enlargement of parapapillary atrophy. The reasons and mechanisms responsible for these similarities and dissimilarities are discussed. Marked clinical, morphologic, and histopathologic similarities in optic disc cupping and loss of neuroretinal rim between A-AION and glaucomatous optic neuropathy are highly suggestive of a common mechanism for the development of the two diseases (i.e., ischemia of the optic nerve head). The subject is discussed at length.

Glaucoma surgery with or without adjunctive antiproliferatives in normal tension glaucoma: 2 Visual field progression

BACKGROUND

Reduction of intraocular pressure by 20-30% with glaucoma drainage surgery slows disease progression in normal tension glaucoma (NTG). It is not clear whether adjunctive antiproliferative agents are necessary or safe in eyes at low risk for scarring.

METHOD

61 eyes of 61 white patients with NTG who had undergone a primary guarded fistulising procedure were reviewed. 20 eyes had no antiproliferatives (nil), 29 had peroperative 5-fluorouracil (5-FU), and 12 had peroperative mitomycin C (MMC). Pointwise linear regression analysis (PROGRESSOR for Windows software) was applied to their visual field series starting with the first visual field following surgery and adding subsequent visual fields one at a time. Progression of visual field loss was defined as the appearance of a regression slope 1 dB per year or more with a significance of p<0.01 at one or more visual field locations which remained consistent with the addition of two of three successive visual fields. Time updated covariate analysis was used to determine the relation between variables that changed with time, such as IOP, and the risk of progression.

RESULTS

The median percentage IOP reduction was 24.4 for the nil group, 38.0 for the 5-FU group, and 47.5 for the MMC group (p=0.001). There was a statistically significant relation between percentage change in IOP and risk of visual field progression in the subsequent 6 month period for all patients analysed as one group, hazard ratio = -0.021 (p=0.002). There was a statistically significantly increase in the risk of visual field progression for the MMC group compared with the 5-FU group, hazard ratio = 1.51 (p=0.02).

CONCLUSION

In NTG patients, the IOP reduction produced by drainage surgery reduces the risk that visual field progression may be reduced after drainage surgery; this is related to the level of IOP reduction. The percentage drop in IOP during a given time is related to the risk of subsequent visual field progression. However, the use of MMC is associated with a greater risk of visual field progression despite a greater fall in IOP. This visual field deterioration may be related to the functional loss produced by late postoperative complications which have been reported at a higher rate in this group. The use of adjunctive perioperative 5-FU should maintain a suitable target IOP with preservation of visual function without the additional complications and associated visual deterioration seen with adjunctive MMC.

The use of antimetabolites with trabeculectomy: a critical appraisal

PURPOSE

To examine why most ophthalmologists routinely use mitomycin C or 5-fluorouracil (antimetabolites) in association with filtering surgery for glaucoma.

METHODS

Critical analysis of seven medical, social and economic trends.

RESULTS

The rapid acceptance of the adjunctive use of antimetabolites at the time of filtration surgery may be explained by reasons other than anticipated increase in the "success" of glaucoma surgery.

CONCLUSION

The use of antimetabolites in conjuction with filtering glaucoma surgery may be at least partially a consequence of changing medical-social-economic factors, rather than solely a desire on the part of physicians to improve the "success" of glaucoma surgery. This may indicate a need to reevaluate the proper place of antimetabolites in association with filtration surgery.

Glaucoma surgery with or without adjunctive antiproliferatives in normal tension glaucoma: 1 intraocular pressure control and complications

BACKGROUND

Reduction of intraocular pressure (IOP) by 20-30% with glaucoma drainage surgery slows disease progression in normal tension glaucoma (NTG). It is not clear whether adjunctive antiproliferative agents are necessary or safe in eyes at low risk for scarring.

METHOD

86 eyes of 73 white NTG patients who had undergone a primary guarded fistulising procedure were reviewed. 25 eyes had no antiproliferatives, 36 had peroperative 5-fluorouracil (5-FU) and 25 had peroperative mitomycin C (MMC). Their postoperative IOPs, complications, and changes in visual acuity were recorded.

RESULTS

Eyes that had no adjunctive antiproliferative less commonly maintained a 20-30% reduction in IOP (47.4% at 2 years) compared with either the 5-FU group (69.4%at 2 years, p=0.01) or the MMC group (64.9% at 2 years, p=0.04). Eyes that had adjunctive MMC more often had late hypotony (28%, p=0.02) and late bleb leak (12%, p<0.001). Eyes that had adjunctive MMC also more often had a two lines loss of Snellen visual acuity (39.8% by 2 years) compared with those that had adjunctive 5-FU (14.7% by 2 years), p=0.06.

CONCLUSION

For NTG patients at low risk of scarring trabeculectomy with adjunctive peroperative 5-FU should maintain a suitable target IOP without the additional sight threatening complications seen with adjunctive MMC.

Optic nerve head appearance in juvenile-onset chronic high-pressure glaucoma and normal-pressure glaucoma

OBJECTIVE

To evaluate the appearance of the optic nerve head in chronic high-pressure glaucoma and normal-pressure glaucoma.

DESIGN

Clinic-based cross-sectional study.

PARTICIPANTS

The study included 52 eyes with normal-pressure glaucoma and 28 eyes with juvenile-onset primary open-angle glaucoma that served as models for chronic high-pressure glaucoma.

METHODS

Color stereo optic disc photographs and wide-angle retinal nerve fiber layer photographs were morphometrically examined.

MAIN OUTCOME MEASURES

Localized retinal nerve fiber layer defects; parapapillary chorioretinal atrophy; disc hemorrhages; optic cup shape; retinal arteriole narrowing.

RESULTS

Both study groups did not vary significantly in count of localized retinal nerve fiber layer defects, size of parapapillary atrophy, optic cup depth, steepness of disc cupping, rim/disc area ratio, diameter of retinal arterioles, and frequency and degree of focal retinal arteriole narrowing. In normal-pressure glaucoma versus juvenile open-angle glaucoma, localized retinal nerve fiber layer defects were significantly broader, disc hemorrhages were found significantly more often and were larger, and neuroretinal rim notches were present more frequently and were deeper.

CONCLUSIONS

Chronic high-pressure glaucoma and normal-pressure glaucoma show morphologic similarities in the appearance of the optic nerve head. The lower frequencies of detected disc hemorrhages and rim notches in high-pressure glaucoma may be due to a smaller size of hemorrhages and localized retinal nerve fiber layer defects in high-pressure glaucoma. Both glaucoma types have morphologic features in common, suggesting that they may possibly belong to a spectrum of the same pathologic process.

The effect of once-daily latanoprost on intraocular pressure and pulsatile ocular blood flow in normal tension glaucoma

PURPOSE

To determine the effect of once-daily 0.005% latanoprost on intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) in patients with normal tension glaucoma (NTG).

METHODS

The diurnal IOP and sitting POBF were determined for 32 eyes of 19 NTG patients after a washout period. The subjects were treated with 0.005% latanoprost for 3-4 weeks and the measurements repeated. Statistical analysis was performed using the Wilcoxon signed rank test.

RESULTS

Median IOP before and after treatment were 19 and 15 mmHg respectively (p < 0.001). The IOP reduction correlated with the initial IOP before treatment (p < 0.01) and was accompanied by an increase in median POBF from 656 to 796 microliters/min (p < 0.001).

CONCLUSIONS

Once-daily treatment with 0.005% latanoprost provides a significant and stable IOP reduction in the majority of NTG patients after short-term treatment. This is accompanied by a significant increase in POBF.