Magnitude Of Intraocular Pressure Reduction Research Articles

MicroPulse® Transscleral Laser Therapy - Fluence May Explain Variability in Clinical Outcomes: A Literature Review and Analysis.

Since the first peer-reviewed publication on MicroPulse® Transscleral Laser Therapy (MP-TLT) in 2010, authors worldwide have used a wide range of treatment parameter combinations with varying clinical efficacy in terms of the magnitude of intraocular pressure reduction, success rate, durability, and safety profile. This has made it difficult to determine the proper parameters necessary to optimize efficacy and safety, and has made comparison of results from one investigation to another difficult. The first goal of this paper is to explain and highlight the impact of the choices of exposure time and the number of sweeps per hemisphere in terms of “sweep velocity” on energy delivery to the eye. These treatment parameters are underreported in the literature. The second goal is to introduce fluence as a “dose” metric, that combines all the treatment parameters and constants into a single number. Fluence may be a better light-dose metric and a more reliable indicator of clinical outcomes compared to total energy.

The association between corneal hysteresis and surgical outcomes from trabecular meshwork microinvasive glaucoma surgery.

To assess whether an association exists between pretreatment corneal hysteresis (CH) and the magnitude of intraocular pressure (IOP) and medication burden reduction following microinvasive glaucoma surgery (MIGS). Retrospective chart review of 84 eyes from 57 patients with CH measurements who underwent trabecular meshwork MIGS in a glaucoma practice in New York City with follow-up visits at 3-6 and 9-12 months. MIGS included canaloplasty, goniotomy, microbypass stents, or a combination thereof. The lowest and middle CH tertiles experienced significantly reduced mean IOP at 3-6-month follow-ups (p = .007, < .001), whereas the highest tertile did not (p = .06). At 9-12-month follow-ups, a significant mean IOP reduction only persisted in the middle tertile (p = .001). For medication burden reduction, only the highest CH tertile experienced significant mean reductions at both 3-6- and 9-12-month follow-ups (p = .015, .028). Notably, 7 patients in the lowest CH tertile failed MIGS and required an additional surgical or laser procedure within 24 months of MIGS, whereas only 3 patients failed in the other tertiles (likelihood ratio < .05). Multivariate analysis excluding MIGS failures demonstrated an inverse association between CH and the magnitude of post-operative IOP reduction at both 3-6- and 9-12-month follow-ups when controlling for baseline IOP and medication changes (p = .002, .026). There was an inverse association between pretreatment CH and the magnitude of IOP reduction following surgery. There is also evidence of an increased need for repeat surgery or other intervention in patients with lower CH who undergo MIGS.

Efficacy of Needling Revision After XEN Gel Stent Implantation: A Prospective Study

The XEN gel stent is currently the only minimally invasive glaucoma surgical device that targets the subconjunctival outflow pathway through an ab interno placement. It has demonstrated a significant intraocular pressure (IOP)-lowering potential and a favorable safety profile compared with traditional filtering surgery. However, despite a less invasive approach, the presence of a filtering bleb inevitably implies some risk of complications. The most commonly reported bleb-related complication, with rates as high as 45%, is bleb fibrosis associated with raised IOP. To restore filtration in those failing blebs, needling revision is considered the procedure of choice. In this study, we present the results of mitomycin C-augmented needling after XEN implantation. This was a prospective, interventional study, conducted at a single tertiary glaucoma center. Fifty-one eyes of 51 patients with raised IOP associated with either a fibrotic or shallow bleb or increased vascularity following XEN gel stent implantation at the investigation site between January 2015 and June 2016 were enrolled in this study. Patients with other identified causes of filtration failure (stent malposition, internal ostium obstruction, retained viscoelastic) were excluded. Included patients who underwent mitomycin C-augmented needling revision, and follow-up examinations were conducted at 1 day, 1 week, and 1, 3, 6, 12, 18, and 24 months. The primary outcome was the magnitude of IOP reduction following needling revision at the last follow-up visit. Secondary outcome measures were the number of needling procedures carried out in all patients, the rate of patients requiring further filtering surgery following needling revision, and the rate of intraoperative and postoperative complications associated with needling revisions. The average age was 74.4±9.6 years; 66.7% (n=34) were female individuals. Primary open-angle glaucoma was the most common diagnosis (n=21, 41.2%). A total of 78 needling procedures were performed over the 24-month follow-up. Overall 20 of 51 eyes (39.2%) required >1 needling revision, and 14 eyes (24.5%) eventually required reoperation to maintain IOP within their desired target range. Before XEN implantation, mean preoperative IOP was 22.3±8.2 mm Hg and decreased to 14.1±8.0 mm Hg at day 1 postoperatively (-36.8%). The last measured IOP before the first needling revision was on average 23.6±8.9 mm Hg, which reduced to a mean 12.1±4.2 mm Hg at the first postrevision appointment (-48.7%). At the last follow-up appointment, on average 17.0±7.0 months after the first needling, the mean IOP was 14.3±4.1 mm Hg (-35.9% and -39.4% from preoperative and prerevision baselines, respectively). Complications associated with needling revisions were partial amputation of the XEN implant during needling (n=2, 3.9%), hypotony with choroidal detachment (n=1, 2%), and failure to achieve target IOP requiring subsequent surgery (n=14, 27.5%). No association was found between any of the recorded characteristics and the number of needling revisions performed or their outcomes. The present study shows that needling revision following XEN gel stent implantation is a relatively safe and efficient intervention to restore filtration in failing blebs, with a significant and durable IOP-reduction potential.

Factors associated with lamina cribrosa displacement after trabeculectomy measured by optical coherence tomography in advanced primary open-angle glaucoma

To investigate the relationship of lamina cribrosa displacement to corneal biomechanical properties and visual function after mitomycin C-augmented trabeculectomy. Eighty-one primary open-angle eyes were imaged before and after trabeculectomy using an enhanced depth spectral domain optical coherence tomography (SDOCT). Corneal biomechanical properties were measured with the ocular response analyzer before the surgery. The anterior lamina cribrosa (LC) was marked at several points in each of the six radial scans to evaluate LC displacement in response to intraocular pressure (IOP) reduction. A Humphrey visual field test (HVF) was performed before the surgery as well as 3 and 6months, postoperatively. Factors associated with a deeper baseline anterior lamina cribrosa depth (ALD) were cup-disc ratio (P= 0.04), baseline IOP (P= 0.01), corneal hysteresis (P= 0.001), and corneal resistance factor (P= 0.001). After the surgery, the position of LC became more anterior (negative), posterior (positive), or remained unchanged. The mean LC displacement was - 42μm (P= 0.001) and was positively correlated with the magnitude of IOP reduction (regression coefficient = 0.251, P= 0.02) and negatively correlated with age (regression coefficient = - 0.224, P= 0.04) as well as baseline cup-disk ratio (Regression coefficient = - 0.212, P= 0.05). Eyes with a larger negative LC displacement were more likely to experience an HVF improvement of more than a 3dB gain in mean deviation (P= 0.002). A larger IOP reduction and younger age was correlated with a larger negative LC displacement and improving HVF. The correlation between lower SDOCT cup-disc ratio and postoperative negative LC displacement was borderline (P = 0.05). Corneal biomechanics did not predict LC displacement.

Simultaneous evaluation of the lamina cribosa position and choroidal thickness changes following deep sclerectomy.

To assess the changes in peripapillary and macular choroidal thickness, and in the lamina cribrosa position following deep sclerectomy. Prospective study, including 39 eyes with open-angle glaucoma following deep sclerectomy. Choroidal thickness was automatically measured using swept-source optical coherence tomography at four peripapillary locations (superior, temporal, inferior, and nasal) and at the macular area in nine fields plotted with Early Treatment Diabetic Retinopathy Study grid. Optic nerve head was evaluated by Spectralis optical coherence tomography with enhanced depth imaging technology. All measurements were performed preoperatively and at 1 week and 2 months after surgery. The mean intraocular pressure significantly decreased 1 week and 2 months after surgery ( p < 0.001). A significant peripapillary choroidal thickening was observed at all locations 1 week postoperatively ( p ≤ 0.002) and in the temporal quadrant 2 months after surgery ( p = 0.027). There was a significant thickening in all macular choroidal thickness measurements at 1 week ( p < 0.001) and 2 months ( p < 0.05), except at subfoveal and inner nasal locations. The mean peripapillary and macular choroid thickness was 22.8% and 19.7% at 1 week and 6.2% and 7.8% at 2 months, respectively. A significant forward lamina cribrosa displacement occurred at every postoperative stage ( p < 0.001). Multivariate analysis showed a significant correlation between the magnitude of intraocular pressure reduction and the anterior lamina cribrosa movement (0.623, p = 0.000) and a negative correlation between the intraocular pressure change and the mean peripapillary and macular choroidal thickening (-0.527, p = 0.002; -0.568, p = 0.002, respectively). There was a significant reversal lamina cribrosa displacement measured from Bruch's membrane opening reference despite a significant peripapillary choroidal thickening following deep sclerectomy. Both findings were significantly correlated with the change in intraocular pressure.

Selective laser trabeculoplasty for early glaucoma: analysis of success predictors and adjusted laser outcomes based on the untreated fellow eye.

BackgroundTo identify success predictors and to study the role of the fellow untreated eye as a co-variable for adjustment of intraocular pressure (IOP) outcomes following selective laser trabeculoplasty (SLT) in early open-angle glaucoma (OAG) patients.MethodsA case series was carried out. Patients with uncontrolled early OAG or ocular hypertension (inadequate IOP control requiring additional treatment) underwent SLT (one single laser session) performed by the same surgeon in a standardized fashion. The same preoperative medical regimen was maintained during follow-up for all patients. Post-treatment assessments were scheduled at week 1 and months 1, 2, and 3. In order to account for possible influence of IOP fluctuation on laser outcomes, post-laser IOP values of the treated eye of each patient were also analyzed adjusting for IOP changes (between visits variation) of the untreated fellow eye (adjusted analysis). Pre and post-laser IOP values were compared using paired t-test. Factors associated with the magnitude of IOP reduction were investigated using multiple regression analysis.ResultsA total of 45 eyes of 45 patients were enrolled. Mean IOP was reduced from 20.8 ± 5.1 to 14.9 ± 2.9 mmHg at month 3 (p < 0.001). Adjusted success rate (defined as IOP reduction ≥ 20%) was 64% and mean percentage of IOP reduction was 23.1 ± 14.3% at last follow-up visit. Considering unadjusted post-laser IOP values, it was found a 20% greater absolute IOP reduction (median [interquartile range] 6 mmHg [4–7] vs 5 mmHg [3–7]; p = 0.04), with a success rate of 76%. Although baseline IOP was significantly associated with both adjusted and unadjusted post-laser IOP reduction, a stronger association was found when unadjusted IOP values were considered (p < 0.001 and R 2 = 0.35; p < 0.001 and R 2 = 0.67, respectively). Age, mean deviation (MD) index, central corneal thickness and type of glaucoma were not significant predictors (p ≥ 0.150).ConclusionsIn this group of patients with early OAG or ocular hypertension, our short-term results confirmed SLT as a safe and effective alternative for IOP reduction. Although better outcomes were found in eyes with higher preoperative IOP, this effect was mitigated when results were adjusted to the fellow untreated eye (to the influence of between visits-IOP fluctuations).

Changes in choroidal thickness after intraocular pressure reduction following trabeculectomy.

To evaluate the changes of peripapillary and subfoveal choroidal thickness (CT) after trabeculectomy. Prospective longitudinal study included 37 eyes with open-angle glaucoma. The subfoveal and peripapillary CT was measured using enhanced depth imaging spectral domain optical coherence tomography before trabeculectomy and 1week, 3 and 6months postoperatively. The associations between changes in the CT, intraocular pressure (IOP) and axial length were analysed. The medium subfoveal CT (IQR) increased from 182 (97)μm at baseline to 267 (107)μm 1week, 213 (97)μm 3months and 207 (91)μm 6months postoperatively (p<0.001). The peripapillary CT increased in all four quadrants at all follow-ups (p<0.05). The subfoveal and peripapillary choroidal thickening correlated with the magnitude of IOP reduction (p<0.05) and axial length shortening (p<0.01) during whole follow-up period. There was a peripapillary CT increase of 2.9μm per mmHg of IOP reduction (p<0.001, CI 1.5-4.4) and 4.8μm per mm of baseline axial length (p=0.049, CI 0.03-9.6) 1week postoperatively after adjustment for baseline IOP. Six months postoperatively, the decrease in axial length was the only factor associated withperipapillary choroidal thickening (p=0.031; regression coefficient: 73.29μm/mm, CI 7.1-139.5). Intraocular pressure (IOP) reduction after trabeculectomy caused the increase in subfoveal and peripapillary CT for at least 6months postoperatively correlating with greater IOP reduction and axial length shortening. In the long term, the decrease in axial eye length, but not IOP, was the only factor to be associated with peripapillary choroidal thickening.

Modified 360-degree Suture Trabeculotomy for Pseudoexfoliation Glaucoma: 12-Month Results.

We aimed to evaluate the 12-month results of a modified 360-degree suture trabeculotomy (ST) technique in patients with pseudoexfoliation glaucoma (XFG). The modified 360-degree ST was performed on 20 eyes of 20 consecutive patients with XFG resistant to maximal topical treatment. In 8 patients, ST was combined with phacoemulsification. The main outcome measures were the surgical success rate, the mean postoperative intraocular pressure (IOP), the number of antiglaucoma medications, and the operative complications. The baseline IOP (26.55 ± 8.91) and medications (3.15 ± 0.81) decreased significantly to 10.90 ± 2.73 mm Hg and 0.30 ± 0.80, respectively, at 12 months postoperatively (P<0.001). The magnitude of IOP reduction was 58.9%. Complete and qualified success rates were 68.4% and 94.7%, respectively. The entire circumference of Schlemm's canal was opened successfully in all cases. Hyphema, perforation of the trabeculodesmetic window, posterior synechia, peripheral anterior synechia, and a transient elevation of the IOP were noted. The results are comparable to our 6-month results and other previously published results for circumferential trabeculotomy. The modified 360-degree ST provides a feasible choice in patients with XFG with a reasonable rate of complications. The 12-month success rates are promising. It can also be combined effectively with the current cataract surgery.

The effect of phacoemulsification on intraocular pressure in eyes with primary angle closure glaucoma after trabeculectomy

To evaluate the effect of phacoemulsification on intraocular pressure (IOP) in filtered eyes with primary angle closure glaucoma (PACG). In this retrospective case series, 47 eyes from 47 PACG patients who previously had trabeculectomy were consecutively enrolled. All patients had visually significant cataracts and phacoemulsification was performed at least 3 months after trabeculectomy. The IOPs were recorded preoperatively, 1 day, 1 week, 2 weeks, 1 month, 3 months, 6 months, 12 months and 24 months after surgery. The best correct visual acuity (BCVA) , the number of glaucoma medications and the filtered bleb grade were recorded preoperatively and 24 months after phacoemulsification. IOP and BCVA before and after phacoemulsification were compared by student t test. The frequences of antiglaucoma medicine, bled grade and IOP control before and after phacoemulsification were compared by Mann-Whitney Test. Linear regression analysis, Pearson and Spearman were performed to assess the correlation between IOP change and other variants. IOP was decreased significantly from (18.7±6.7) mmHg (1 mmHg=0.133 kPa) at baseline to 16.4±2.0 mmHg at final follow-up (t=2.54, P=0.015) . The median number of glaucoma medications was significantly decreased (P<0.01) at 2 years postoperatively. The magnitude of IOP reduction was significantly correlated with preoperative IOP (r=0.95, P<0.01). BCVA (LogMAR) was improved significantly at month 24 (t=5.62, P<0.01). Filtered bleb decreased insignificantly at 2 years postoperatively (P=0.113). Complete success, qualified success and failure rates in terms of IOP were 61.7%, 27.7% and 10.6% before surgery , 89.4%, 8.5%, 2.1% at 2 years postoperatively. In 29 patients with preoperative IOP≤21 mmHg, mean IOP increased insignificantly from (14.5±4.0) mmHg to (15.5 ± 2.3) (P=0.195) at 2 years. In the 18 patients with preoperative IOP> 21 mmHg, mean IOP decreased from (25.3 ± 4.4) mmHg preoperatively to (17.8 ± 2.4) mmHg (P<0.01). Phacoemulsification reduces IOP and the number of glaucoma medications in previously filtered PACG eyes. The IOP remained normal in normal tension eyes after phacoemulsification in filtered PACG eyes but decreased significantly in hypertensive eyes.

Reduced intraocular pressure after cataract surgery in patients with narrow angles and chronic angle-closure glaucoma

To evaluate the effect of cataract surgery on intraocular pressure (IOP) in patients with narrow angles and chronic angle-closure glaucoma (ACG) and to determine whether the change in IOP was correlated with the preoperative pressure, axial length (AL), and anterior chamber depth (ACD). Private practice, Atlanta, Georgia, USA. Retrospective case series. Charts of patients with narrow angles or chronic ACG who had cataract surgery were reviewed. All eyes had previous laser iridotomies. Data recorded included preoperative and postoperative IOP, AL, and ACD. The preoperative IOP was used to stratify eyes into 4 groups. The charts of 56 patients (83 eyes) were reviewed. The mean reduction IOP in all eyes was 3.28 mm Hg (18%), with 88% having a decrease in IOP. There was a significant correlation between preoperative IOP and the magnitude of IOP reduction (r = 0.68, P < .001). The mean decrease in IOP was 5.3 mm Hg in eyes with a preoperative IOP above 20 mm Hg, 4.6 mm Hg in the over 18 to 20 mm Hg group, 2.5 mm Hg in the over 15 to 18 mm Hg group, and 1.4 mm Hg in the 15 mm Hg or less group. The mean follow-up was 3.0 years ± 2.3 (SD). Cataract surgery reduced IOP in patients with narrow angles and chronic ACG. The magnitude of reduction was highly correlated with preoperative IOP and weakly correlated with ACD. No author has a financial or proprietary interest in any material or method mentioned.

Contralateral intraocular pressure lowering effect of prostaglandin analogues.

Background:Though the use of prostaglandin analogues (PGA) for reduction of intraocular pressure (IOP) has shown a marked increase, studies evaluating the contralateral effects of PGA are limited.Aims:To evaluate if PGA treatment in one eye has an effect on the IOP of the untreated fellow eye.Design:Retrospective study.Materials and Methods:Thirty patients of open-angle glaucoma with no previous antiglaucoma treatment underwent 24-hour diurnal IOP phasing. They subsequently were started on a uniocular trial with PGA, and had office diurnal IOP measurements 6 weeks later. Twenty-four hour diurnal consisted of 8 IOP readings over 24 hours and office diurnal consisted of 4 IOP readings between 8 AM and 6 PM at 3 hourly intervals.Statistical Analysis:IOPs of the fellow eye during the office diurnal were compared with IOPs at similar time points during the 24-hour diurnal using paired t-tests.Results:Mean (± standard deviation) IOP in the treated eye reduced (P < 0.001) from 17.17 ± 3.2 mm Hg at baseline to 13.7 ± 2.4 mm Hg at 6 weeks, while that in the untreated eye reduced from 16.4 ± 3.1 mm Hg to 14.8 ± 2.7 mm Hg (P = 0.01). The decrease in IOP in the untreated fellow eye was statistically significant at 8 AM (2.7 mm Hg, P = 0.003) and 11 AM (2.3 mm Hg, P = 0.01) but not so at 2 PM (1.2 mm Hg, P = 0.10) and 5 PM (0.9 mm Hg, P = 0.19). The amount of IOP reduction in the untreated eye was significantly associated with the magnitude of IOP reduction in the treated eye (β = 0.69, P = 0.008).Conclusion:Uniocular PGA treatment tends to reduce the IOP of the untreated fellow eye.

Efficacy and safety of deep sclerectomy in childhood glaucoma in Saudi Arabia

To evaluate the efficacy and safety of deep sclerectomy in childhood glaucoma. A prospective cohort of 120 children presenting with glaucoma to King Abdul Aziz University Hospital (KAUH) was subjected to nonpenetrating deep sclerectomy surgery (NPDS). Eventually, 57 patients had macro perforation and converted to penetrating deep sclerectomy (PDS). Intra-operative mitomycin C (MMC) 0.2 mg/ml was used in all patients. Pre- and postintervention glaucoma indices were assessed. Complete success rate (CSR) was identified as achieving an end-point of intraocular pressure <21 without any antiglaucoma medications. Data were analysed to compare pre- and postintervention changes and to compare both procedures. After follow-up of 35.8 (34.5) months, NPDS procedure went smooth in 74 eyes of 63 patients. The complete success rate was 79.7%, whereas the overall success rate was 82.4%. Thirteen cases failed. The probability to survive was 74.6% after the 12th month. The mean intraocular pressure (IOP) went down to 11.5 ± 3.0 mmHg compared to 31.9 mmHg preoperatively. Comparing cases with NPDS to those with PDS, the magnitude of IOP reduction (15.8) was higher than that of the PDS (14.8); however, this difference was not statistically significant (p = 0.259). Apart from involuntary perforation of trabeculodescemetic window (TDW), neither intra-operative nor early postoperative complications were observed. Deep sclerectomy in childhood glaucoma can effectively reduce the IOP, without the occurrence of serious complications that are commonly seen after trabeculotomy or combined trabeculotomy trabeculectomy.

The relationship between corneal hysteresis and the magnitude of intraocular pressure reduction with topical prostaglandin therapy

AimsTo evaluate corneal hysteresis (CH) and intraocular pressure (IOP) before and after IOP lowering with prostaglandin analogue (PGA) therapy in medication-naïve eyes.MethodsIn this retrospective study, we included records from 57...

Factors associated with topographic changes of the optic nerve head induced by acute intraocular pressure reduction in glaucoma patients

To investigate factors associated with changes in optic nerve head (ONH) topography after acute intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG). Untreated POAG patients (IOP >21 mm Hg) were prospectively enrolled. Systemic and ocular information were collected, including central corneal thickness (CCT) and corneal hysteresis (CH). All patients underwent confocal scanning laser ophthalmoscopy and tonometry (Goldmann) before and 1 h after pharmacological IOP reduction. The mean of three measurements was considered for analysis. Changes in each ONH topographic parameter were assessed (one eye was randomly selected), and those that changed significantly were correlated with patient's systemic and ocular characteristics. A total of 42 patients were included (mean age, 66.7 ± 11.8 years). After a mean IOP reduction of 47.3 ± 11.9%, significant changes were observed in cup area and volume, and in rim area and volume (P < 0.01), but not in mean cup depth (P = 0.80). Multiple regression analysis (controlling for baseline IOP and magnitude of IOP reduction) showed that CH (r(2) = 0.17, P < 0.01) and diabetes diagnosis (r(2) ≥ 0.21, P < 0.01) were negatively correlated with the magnitude of changes in ONH parameters, whereas the cup-to-disc ratio was positively correlated (r(2) = 0.30, P < 0.01). Age, race, disc area, and CCT were not significant (P ≥ 0.12). Including all significant factors in a multivariable model, only the presence of diabetes remained significantly associated with all ONH parameters evaluated (P < 0.01). Different systemic and ocular factors, such as diabetes, CH, and the relative size of the cup, seem to be associated with the magnitude of changes in ONH topography after acute IOP reduction in POAG patients. These associations partially explain the ONH changes observed in these patients and suggest that other factors are possibly implicated in an individual susceptibility to IOP.

Selective Laser Trabeculoplasty: Duration and Magnitude of Intraocular Pressure Reduction

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Selective Laser Trabeculoplasty: Duration and Magnitude of Intraocular Pressure Reduction—Reply

Selective Laser Trabeculoplasty: Duration and Magnitude of Intraocular Pressure Reduction—Reply

The effectiveness of latanoprost for the treatment of pediatric glaucoma

Purpose: Latanoprost is a prostaglandin F 2α analogue that substantially reduces intraocular pressure (IOP) in adults with open-angle glaucoma or ocular hypertension. The efficacy and safety of latanoprost in children is unknown. We wished to evaluate latanoprost therapy for children with glaucoma. Methods: This was a prospective study of all patients who were given latanoprost at our institution between September 1996 and January 1998. The baseline IOP was compared with the postlatanoprost IOP for each patient, and side effects and any iris color change were noted at each follow-up examination. Responders were defined as those who had at least a 15% IOP reduction on latanoprost, whereas nonresponders showed less than a 15% IOP reduction on latanoprost. Results: Fifty-seven eyes of 48 pediatric patients with a variety of glaucoma diagnoses and an average age of 7.1 years were included in the study. Of these, 31 eyes of 31 patients had interpretable IOP data; the mean IOP reduction for this group after the addition of latanoprost was 0.9% (0.2 mm Hg). Six patients (6 eyes) were responders, with an average IOP reduction of 8.5 mm Hg (34%), whereas the majority of patients (25) were nonresponders. In the responders, there was a good correlation ( r = 0.9) between baseline IOP and the magnitude of IOP reduction. Responders were significantly more likely to have juvenile open-angle glaucoma and to be older than nonresponders. Systemic and ocular side effects were infrequent and mild, and no patient had noticeable iris color changes. Conclusions: When used in a group of pediatric patients with a variety of glaucoma diagnoses and on various therapies, latanoprost is effective in only a minority of cases. In selected patients, however, latanoprost shows an impressive ocular hypotensive effect, comparable with that obtained when this drug is used in adults with open-angle glaucoma. This drug appears to be well tolerated in this short-term study of pediatric patients with glaucoma. (J AAPOS 1999;3:33-9)

Changes in Reversal of Cupping in Experimental Glaucoma: Longitudinal Study

The authors prospectively and longitudinally studied changes in optic disc topography during spontaneous reduction of intraocular pressure (IOP) in five monkeys with experimental glaucoma, using a computerized image analyzing system (Topcon IMAGEnet). Glaucomatous optic neuropathy was produced in one eye of each animal by repeated argon laser photocoagulation of the trabecular meshwork. The duration of follow-up was 12 months. After laser treatment, IOP fluctuated and tended to increase. Spontaneous reduction in IOP was frequently observed during follow-up. Changes in optic disc parameters (vertical and horizontal cup-to-disc ratios, rim area/disc area, cup volume/disc area) that accompanied a given magnitude of spontaneous reduction in IOP at the early stage of glaucoma (first 4 months of follow-up) were compared with those at the later stage of glaucoma (last 4 months of follow-up). All optic disc parameters improved significantly during IOP reduction at each stage of glaucoma. Although there was no significant difference between the two stages in the magnitude of IOP reduction, the extent of improvement in each disc parameter was significantly less in the later stage than in the early stage. In both stages, reversal of cupping occurred symmetrically in the vertical and horizontal dimensions. Expansion of the cup occurred symmetrically in the early stage, but this was predominantly vertical in the later stage. These results suggest that the extent of cupping reversal after IOP reduction may decrease with progressive glaucomatous damage in primate glaucoma.

Intraocular Pressure-denpendent Retinal Vascular Change in Adult Chronic Open-angle Glaucoma Patients

Intraocular pressure (IOP)-dependent retinal vascular changes were investigated in 33 eyes of 33 adult chronic open-angle glaucoma (COAG) patients by measuring major retinal vascular calibers at the optic disc border before and after mean (± standard deviation) IOP reduction from 35.3 (±7.2) to 16.5 (±4.7) mmHg for 11.2 (±13.5) weeks. Both mean arterial and venous calibers were significantly reduced (P < 0.0001 for each), from 87.8 (±14.2) and 128.3 (±20.8) Am at high IOP to 82.0 (±13.8) and 121.4 (±18.5) µm at low IOP. Arterial and venous caliber decreases correlated positively with magnitude of IOP reduction (P = 0.503, P < 0.01 and r = 0.555, P < 0.001, respectively). While the IOP-dependent retinal arterial caliber change was highly significant in patients 55 years of age or younger (P = 0.636, P < 0.01) and in the overall study group, it was not significant in patients older than 55 years (P = 0.205, P > 0.1). Age seems to be more influential than magnitude of IOP reduction in patients older than 55. Thus, diminished IOP-dependent retinal arterial caliber change in the elderly may be one factor contributing to the higher incidence and prevalence of glaucoma in this population.

Clinical, structural and molecular phototherapy effects of laser irradiation on the trabecular meshwork of human glaucomatous eyes

The effects of argon laser trabeculoplasty (LTP) on intraocular pressure (IOP), outflow facility, the morphology of the trabecular meshwork (TM), and the pattern of extracellular glycoprotein fibronectin in trabeculum were studied in 46 eyes of patients with primary open-angle glaucoma (POAG). The LTP was done with informed consent, anticipating that trabeculectomy would be carried out at a scheduled time (2 h to several months following laser therapy). We found that the magnitude of IOP reduction and the improvement in the facility of outflow achieved are directly dependent on the time course after LTP and laser-induced structural changes in trabecular tissue. Light microscopic and immunohistochemical evaluations of the TM specimens at earlier intervals after LTP revealed evidence of heat effects, with disruption and shrinkage of the TM collagenous components and accumulation of fibronectin deposits in the aqueous drainage channels as compared with the TMs of matched patients with POAG who did not receive laser treatment. Within 24 h after LTP, proteins of glaucomatous TMs excised from patients incorporated increased amounts of [3H]-leucine radioactive label; however, the amount of [3H]-leucine-labeled material was significantly depressed in later periods of evaluation. The specimens obtained at longer intervals after LTP showed partial or total occlusion of the intertrabecular spaces by extracellular debris; however, the amount of trabecular fibronectin was not significantly different from that measured 24 h after LTP. At least two potential mechanisms are proposed for the TM tissue response to laser treatment, including heat-induced stretching of the collagen in lamellae and fibronectin-mediated attachment of beams supporting an adhesive tightening of the trabecular components caused by LTP. The changes in laser-induced tissue responses appear to be the result of morphological repair of irradiation-injured trabecular tissue.