Aqueous Humor Dynamics in Ocular Hypertensive Patients

Toris, Carol B.; Koepsell, Scott A.; Yablonski, Michael E.; Camras, Carl B.

doi:10.1097/00061198-200206000-00015

Cited by 88 publications

(53 citation statements)

References 27 publications

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“…AIT enhances the normal, conventional outflow by removing the trabecular meshwork that constitutes the majority of outflow resistance [17,18]. In contrast, epibulbar glaucoma drainage implants bypass both the conventional and the uveoscleral route entirely but are subject to encapsidation that is the result of fibrosis and a chronic foreign body reaction [19].…”

Section: Discussionmentioning

confidence: 99%

Longer-term Baerveldt to Trabectome glaucoma surgery comparison using propensity score matching

Kostanyan

Shazly

Kaplowitz

et al. 2017

Graefes Arch Clin Exp Ophthalmol

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1 AbstractPurpose: To apply propensity score matching to compare Baerveldt glaucoma drainage implants (BGI) to trabectome-mediated ab interno trabeculectomy (AIT). Recent data suggests that AIT can produce results similar to BGI which is traditionally reserved for more severe glaucoma.Methods: BGI and AIT patients with at least one year of follow-up were included. The primary outcome measures were intraocular pressure (IOP), number of glaucoma medications, and a Glaucoma Index (GI) score. GI reflected glaucoma severity based on visual field, the number of preoperative medications, and preoperative IOP. Score matching used a genetic algorithm consisting of age, gender, type of glaucoma, concurrent phacoemulsification, baseline number of medications, and baseline IOP. Patients with neovascular glaucoma, with prior glaucoma surgery or without a close match were excluded.Results: Of 353 patients, 30 AIT patients were matched to 29 BGI patients. Baseline characteristics including, IOP, the number of glaucoma medications, type of glaucoma , the degree of VF loss and GI were not significantly different between AIT and BGI. BGI had a preoperative IOP of 21.6±6.3 mmHg compared to 21.5±7.4 for AIT on 2.8±1.1 medications and 2.5±2.3, respectively. At 30 months, the mean IOP was 15.0±3.9 mmHg for AIT versus 15.0±5.7 mmHg for BGI (p>0.05), while the number of drops was 1.5±1.3 for AIT (change: p=0.001) versus 2.4±1.2 for BGI (change: p=0.17; AIT vs BGI: 0.007). Success, defined as IOP<21 mmHg, <20% reduction and no reoperation, was achieved at 1 year in 56% of AIT versus 55% of BGI (p>0.05) and 50% versus 52% at 2.5 years. Conclusions:A propensity score matched comparison of AIT and BGI demonstrated a similar IOP reduction through one year. AIT required fewer medications.2

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Section: Discussionmentioning

confidence: 99%

Longer-term Baerveldt to Trabectome glaucoma surgery comparison using propensity score matching

Kostanyan

Shazly

Kaplowitz

et al. 2017

Graefes Arch Clin Exp Ophthalmol

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“…Accordingly, Liu et al and Fan et al have reported daytime versus nighttime differences in aqueous humor dynamics between OHTN and normotensive subjects, 17,18 with significant reductions in nighttime outflow facility in normotensive but not OHTN subjects. This, in addition to the already low daytime outflow facility in OHTN patients, 19 may partially explain the above findings. When we excluded the effect of posture, we found that the mean IOP levels changed in opposing directions: increasing in healthy controls and decreasing in the OHTN and glaucoma groups.…”

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confidence: 81%

“…As previously suggested by Liu et al, 7 these observations may reflect various endogenous mechanisms yet to be identified that may be responsible for the IOP pattern in ocular hypertensives. One possibility is that early dysfunction in the trabecular meshwork in patients with OHTN, 19 and the resultant reduction in pressure-sensitive aqueous outflow in addition to the increased diurnal aqueous production, 20 may partially explain our findings.…”

mentioning

confidence: 86%

Twenty-Four–Hour Pattern of Intraocular Pressure in Untreated Patients with Ocular Hypertension

Grippo

Liu²,

Zebardast

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To characterize the 24-hour pattern of intraocular pressure (IOP) in untreated ocular hypertensive (OHTN) patients.METHODS. IOP measurements were taken every 2 hours during a 24-hour period from 15 untreated OHTN patients (ages 41-77 years). Measurements were both sitting and supine (diurnal) and supine only (nocturnal). Mean diurnal and nocturnal IOPs in the OHTN group were compared to previously reported values in age-matched healthy and glaucomatous eyes. Post hoc analysis compared the 24-hour IOP pattern of the OHTN patients who converted to glaucoma and those who did not with that in the same healthy and glaucomatous eyes.RESULTS. Mean sitting and supine IOPs were significantly higher in the OHTN group than in the healthy control but not the glaucoma group. Similar to the glaucoma group, the OHTN group demonstrated significant differences from healthy controls in diurnal IOP variation and IOP changes upon awakening in habitual and supine positions. The 24-hour IOP curve acrophases and amplitudes for OHTNs were closer to those of the glaucoma than the healthy control group in the habitual position. Thirty-three percent of OHTNs developed glaucoma during a mean follow-up period of 4.3 6 3.8 years. Similar to findings in the glaucoma group, habitual IOP curve phase delay, habitual IOP variation, diurnal-to-nocturnal IOP changes, and IOP changes upon awakening of the converters were significantly different from those in healthy controls. There were no differences between nonconverters and other groups.CONCLUSIONS. Baseline 24-hour IOP pattern in OHTN patients is similar to that in glaucomatous patients. In contrast to nonconverters, OHTN patients who converted to glaucoma are significantly different from healthy controls. (Invest Ophthalmol Vis Sci. 2013;54:512-517)

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“…The site of increased resistance in eyes with glaucoma is thought to be located at the juxtacanalicular connective tissue and the endothelial lining of Schlemm's canal as a result of composition changes in extracellular matrix components. 14,26,32,33,42,72,74,114 Outflow facility in ocular hypertensive 120 and OAG patients is significantly lower than in age-matched controls. 55 Recent results indicate that outflow facility is decreased at night in older healthy individuals.…”

Section: A the Conventional Pathwaymentioning

confidence: 91%

24-hour Intraocular Pressure and Ocular Perfusion Pressure in Glaucoma

Quaranta

Katsanos

Russo

et al. 2013

Survey of Ophthalmology

135

137

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Abstract. This review analyzes the currently available literature on circadian rhythms of intraocular pressure (IOP), blood pressure, and calculated ocular perfusion pressure (OPP) in patients with openangle glaucoma. Although adequately powered, prospective trials are not available. The existing evidence suggests that high 24-hour IOP and OPP fluctuations can have detrimental effects in eyes with glaucoma. The currently emerging continuous IOP monitoring technologies may soon offer important contributions to the study of IOP rhythms. Once telemetric technologies become validated and widely available for clinical use, they may provide an important tool towards a better understanding of longand short-term IOP fluctuations during a patient's daily routine. Important issues that need to be investigated further include the identification of appropriate surrogate measures of IOP and OPP fluctuation for patients unable to undergo 24-hour measurements, the determination of formulae that best describe the relationship between systemic blood pressure and IOP with OPP, and the exact clinical relevance of IOP and OPP fluctuation in individual patients. Despite the unanswered questions, a significant body of literature suggests that OPP assessment may be clinically relevant in a significant number of glaucoma patients. (Surv Ophthalmol 58:26--41, 2013. Ó 2013 Elsevier Inc. All rights reserved.) Key words. glaucoma circadian rhythm intraocular pressure blood pressure ocular perfusion pressure I. Physiological ConsiderationsThe principal physiological entities that affect intraocular pressure (IOP) and its characteristics are the aqueous humor (AH) dynamics in healthy and glaucomatous eyes.The production of AH involves two consecutive processes. First, a portion of the plasma that reaches the vascular plexus of the ciliary processes is filtered through the fenestrated capillaries into the interstitial space between the vessels and the ciliary epithelia. Next, a portion of the filtrate is actively secreted by the ciliary epithelial cells into the posterior chamber.In humans, these processes are affected by age, circadian rhythm, topical and systemic medications, and the presence of glaucoma. 63,64,70,109,121 The rate of AH formation decreases with age: by 15--35% between age 20 and 80 years. 15,30 The rate of AH production in humans is significantly lower at night, 99,119 attributed to decreased endogenous circulating catecholamine levels, which may partly explain the decreased nocturnal efficacy of topical 26

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Aqueous Humor Dynamics in Ocular Hypertensive Patients

Cited by 88 publications

References 27 publications

Longer-term Baerveldt to Trabectome glaucoma surgery comparison using propensity score matching

Longer-term Baerveldt to Trabectome glaucoma surgery comparison using propensity score matching

Twenty-Four–Hour Pattern of Intraocular Pressure in Untreated Patients with Ocular Hypertension

24-hour Intraocular Pressure and Ocular Perfusion Pressure in Glaucoma

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