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Dive into the research topics where Philip P. Chen is active.

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Featured researches published by Philip P. Chen.


Ophthalmology | 2000

Trabeculectomy with intraoperative mitomycin C versus 5-Fluorouracil: Prospective randomized clinical trial

Kuldev Singh; Kala M. Mehta; Naazli M Shaikh; James C. Tsai; Marlene R. Moster; Donald L. Budenz; David S. Greenfield; Philip P. Chen; John S. Cohen; George Baerveldt; Saad Shaikh

OBJECTIVE To evaluate the relative efficacy and safety of 5-fluorouracil (5-FU) and mitomycin C (MMC) when used as adjuncts with primary trabeculectomy in eyes not at high risk for failure. DESIGN Prospective multicenter, randomized clinical trial. PARTICIPANTS One hundred thirteen patients with primary open-angle, pseudoexfoliative, pigmentary, or angle-closure glaucoma undergoing primary trabeculectomy were recruited. METHODS One eye of each patient was randomized to receive either 5-FU (50 mg/ml for 5 minutes) or MMC (0.4 mg/ml for 2 minutes). MAIN OUTCOME MEASURES Intraocular pressure (IOP), visual acuity, complications, and interventions were documented at fixed intervals after surgery. The study also examined progression of visual field loss, long-term complications, and bleb appearance 3 years after surgery. RESULTS Of the 108 patients with complete perioperative information, 54 eyes received 5-FU and 54 received MMC. The proportion of patients reaching different predefined target IOPs after surgery was slightly higher in the MMC group than in the 5-FU group. This difference was less than 25%, which would have been necessary to achieve statistical significance with a power of 0.8 and the sample size used. Likewise, there was no statistically significant difference between the groups with regard to mean preoperative IOP, complications, or interventions. Mean postoperative follow-up was 309 and 330 days in the 5-FU and MMC groups, respectively (P = 0.593). CONCLUSIONS 5-Fluorouracil and MMC were found to be equally safe and effective adjuncts to primary trabeculectomy in the short- and medium-term postoperative periods.


Ophthalmology | 2003

Blindness in patients with treated open-angle glaucoma

Philip P. Chen

PURPOSE To investigate blindness in patients with treated open-angle glaucoma (OAG) and risk factors for blindness. DESIGN Retrospective observational case series. PARTICIPANTS One hundred eighty-six patients seen between April and November 2000 at the University of Washington Medical Center Eye Clinic, diagnosed in 1975 or later, and treated for at least 2 years for OAG. METHODS Chart review with evaluation of visual acuity and visual field. Kaplan-Meier survival analysis was used to estimate the risk of blindness in one and both eyes. Variables considered to be possible risk factors for blindness were evaluated using chi-square test, t test, and Cox proportional hazards regression analysis. MAIN OUTCOME MEASURES Blindness, defined as visual acuity of 20/200 or worse, and/or continuous constriction of the visual field to 20 degrees or less in all four quadrants with a size III4e Goldmann stimulus or the equivalent on automated perimetry, allowing a higher threshold level on one point in one quadrant on automated perimetry. RESULTS The mean duration of disease was 10.2 +/- 4.9 years. Twelve patients were blind in at least one eye from OAG at diagnosis. Nineteen other patients became blind in at least one eye from OAG, and three patients became bilaterally blind from OAG. The Kaplan-Meier estimate for blindness at 15 years in one eye was 14.6%, and in both eyes was 6.4%. Noncompliance with the treatment regimen (P = 0.016) and worse initial visual field loss (P < 0.0001) were significantly associated with development of blindness. Nonwhite race was associated with blindness (P = 0.014) when all blindness, including that found at diagnosis, was considered in the analysis. CONCLUSIONS Bilateral blindness from chronic OAG was uncommon in this population of treated patients diagnosed in 1975 or later. Of patients with a blind eye, 39% were blind at diagnosis, and worse visual field loss at diagnosis and noncompliance were associated with development of blindness.


Journal of Glaucoma | 1997

Use of antifibrosis agents and glaucoma drainage devices in the American and Japanese Glaucoma Societies.

Philip P. Chen; Tetsuya Yamamoto; Akira Sawada; Richard K. Parrish; Yoshiaki Kitazawa

PURPOSE To investigate practice patterns among glaucoma subspecialists in the American Glaucoma Society (AGS) and the Japanese Glaucoma Society (JGS), regarding use of antifibrosis agents and glaucoma drainage devices. METHODS An anonymous survey incorporating 10 clinical situations was mailed to all AGS and JGS members in December 1995. RESULTS Half of the AGS (105 of 210), and JGS (25 of 50) members returned surveys. Most respondents (51-87%) preferred trabeculectomy with adjunctive mitomycin for all 10 clinical situations. Mitomycin concentrations varied from 0.1 to 0.8 mg/ml (range of means for 10 situations 0.31-0.39 mg/ml) and intraoperative application times ranged from 5 s to 7 min (range of means for 10 situations 2.5-4.6 min). Preferences for either no antifibrosis agent (up to 39%) or 5-fluorouracil (up to 29%) were highest in primary trabeculectomy. Thirty-seven percent to 64% of AGS members used glaucoma drainage devices, especially after complicated postsurgical glaucomas (after penetrating keratoplasty, scleral buckling, or pars plana vitrectomy) and in neovascular glaucoma, but few JGS members used them. Large differences between university- and private practice-based AGS members were found only in mitomycin use for primary trabeculectomy (33% vs. 52%, respectively; p = 0.07) and for complicated postsurgical glaucomas (46% vs. 70%, respectively; p = 0.03). CONCLUSIONS Trabeculectomy with mitomycin was the preferred surgical procedure among AGS and JGS members in the clinical situations surveyed. Mitomycin concentration and time of application varied widely. Many respondents used 5-fluorouracil or no antimetabolite in primary trabeculectomy. Glaucoma drainage devices were widely used for complicated glaucomas in the United States.


Ophthalmology | 1998

Trabeculectomy function after cataract extraction

Philip P. Chen; Yaffa K. Weaver; Donald L. Budenz; William J. Feuer; Richard K. Parrish

OBJECTIVE To examine the effect of cataract extraction (CE) after trabeculectomy on intraocular pressure (IOP) control. DESIGN Retrospective noncomparative case series. PARTICIPANTS A total of 115 consecutive patients who underwent extracapsular CE (N = 58) or phacoemulsification (N = 57) with intraocular lens (IOL) placement after trabeculectomy were studied. INTERVENTION Cataract extraction with IOL after trabeculectomy was performed. MAIN OUTCOME MEASURES Preoperative, intraoperative, and postoperative factors were evaluated for association with loss of IOP control requiring additional medications, bleb needling, or further glaucoma surgery, using Kaplan-Meier survival analysis and Cox multivariate proportional hazards survival regression. RESULTS After mean postoperative follow-up of 21.1 +/- 14.3 months, additional glaucoma medication or needling of the filtering bleb to maintain IOP control was required in 35 eyes (30.4%) and was significantly associated with intraoperative iris manipulation and early postoperative peak IOP greater than 25 mmHg. Additional glaucoma surgery was eventually required in 11 eyes (9.6%) and was significantly associated with age of 50 years or younger, preoperative IOP greater than 10 mmHg, and early postoperative peak IOP greater than 25 mmHg. The cumulative proportion of patients who did not require reoperation for glaucoma was 93% and 90% at 1 and 2 years, respectively. The mean IOP at last visit had increased 1.6 mmHg above the pre-CE level and did not vary significantly after the first postoperative month. The median interval from CE to the addition of glaucoma medication or bleb needling was 1.6 months (within 3 months in 20 of 33 eyes) and that from nonsurgical intervention to further glaucoma surgery was 3.6 months (before the 7th postoperative month in 6 of 11 eyes). Of 19 eyes with hypotony (IOP < or = 6 mmHg) before CE, 11 eyes remained hypotonous after CE despite an increase in the mean IOP from 4.6 to 7.5 mmHg. CONCLUSIONS When CE is performed after trabeculectomy, age of 50 years or younger, preoperative IOP greater than 10 mmHg, intraoperative iris manipulation, and early postoperative IOP greater than 25 mmHg are associated with worsened postoperative IOP control. Most bleb failures occur soon after CE. Resolution of pre-existing hypotony after CE is unpredictable.


Ophthalmic Surgery Lasers & Imaging | 2011

Practice preferences for glaucoma surgery: a survey of the american glaucoma society in 2008.

Manishi Desai; Steven J. Gedde; William J. Feuer; Wei Shi; Philip P. Chen; Richard K. Parrish

BACKGROUND AND OBJECTIVE To evaluate glaucoma surgical practice patterns among members of the American Glaucoma Society (AGS). PATIENTS AND METHODS An anonymous web-based survey was sent to AGS members to determine their preferred surgical approach in ten clinical settings. Survey results were compared with those from 1996 and 2002. RESULTS A total of 125 (22%) AGS members responded to the survey. Mean glaucoma drainage device (GDD) usage increased from 17.5% (range: 5% to 37%; standard deviation [SD]: 10.9%) in 1996 to 50.8% (range: 15% to 76%; SD: 17.3%) in 2008, and mean trabeculectomy usage decreased from 80.8% (range: 62% to 93%; SD: 11.3%) in 1996 to 45.5% (range: 16% to 80%; SD: 17.9) in 2008. GDD was most popular in none of 8 clinical settings in 1996, and 5 of 8 clinical settings in 2008. Mitomycin C was selected as an adjunctive antifibrotic agent to trabeculectomy in 85% to 99% of cases. CONCLUSION Glaucoma surgical practice patterns have changed since 1996. The use of a GDD has progressively increased, and the popularity of trabeculectomy decreased between 1996 and 2008. Mitomycin C remains the most frequently selected antifibrotic agent used as an adjunct to trabeculectomy.From Boston Medical Center (MAD), Boston University School of Medicine, Boston, Massachusetts; Bascom Palmer Eye Institute (SJG, WJF, WS, RKP), University of Miami, Miller School of Medicine, Miami, Florida; and the Department of Ophthalmology (PPC), University of Washington, Seattle, Washington.The authors have no financial or proprietary interest in the materials presented herein.Address correspondence to Steven J. Gedde, MD, Bascom Palmer Eye Institute, 900 NW 17th Street, Miami, FL 33136. E-mail: [email protected] Received: January 19, 2011 Accepted: March 09, 2011.


Ophthalmology | 2000

Visual field progression in patients with initially unilateral visual field loss from chronic open-angle glaucoma

Philip P. Chen; Roy J Park

PURPOSE To investigate visual field progression in patients with initially unilateral glaucomatous visual field loss, and to determine risk factors for progression. DESIGN Retrospective observational case series. PARTICIPANTS Forty-eight consecutive patients with primary open-angle glaucoma, pseudoexfoliative glaucoma, or pigmentary glaucoma, seen over an 18-month period, who initially had unilateral visual field loss as defined by use of modified Anderson criteria. Patients were followed with standard Humphrey perimetry for a minimum of 2 years. METHODS Progression was defined by use of modified Anderson criteria, and Advanced Glaucoma Intervention Study (AGIS) and Collaborative Initial Glaucoma Treatment Study scores. MAIN OUTCOME MEASURE Visual field progression. RESULTS Three patients (6.2%) had fellow eye progression over a mean follow-up of 76 months and duration of disease of 8.7 years. Fellow eye progression correlated with progression of the first-affected eye (P = 0.044). Ten patients (21%) had progression of the first-affected eye; these eyes had a larger initial cup/disc ratio compared with stable eyes (P = 0.041). Increasing initial AGIS score was associated with progression (P: = 0.003). Kaplan-Meier survival analysis estimated the risk of progression at 5 years to be 25% in first-affected eyes and 7.2% in fellow eyes. CONCLUSIONS In this population, the risk of fellow eye progression in patients with initially unilateral visual field loss from open-angle glaucoma is low. Progression is higher in eyes with visual field loss at initial testing, and the risk of progression increases as the level of initial visual field loss increases.


Ophthalmology | 2015

The Effect of Phacoemulsification on Intraocular Pressure in Glaucoma Patients: A Report by the American Academy of Ophthalmology

Philip P. Chen; Shan C. Lin; Anna K. Junk; Sunita Radhakrishnan; Kuldev Singh; Teresa C. Chen

OBJECTIVE To examine effects of phacoemulsification on longer-term intraocular pressure (IOP) in patients with medically treated primary open-angle glaucoma (POAG; including normal-tension glaucoma), pseudoexfoliation glaucoma (PXG), or primary angle-closure glaucoma (PACG), without prior or concurrent incisional glaucoma surgery. METHODS PubMed and Cochrane database searches, last conducted in December 2014, yielded 541 unique citations. Panel members reviewed titles and abstracts and selected 86 for further review. The panel reviewed these articles and identified 32 studies meeting the inclusion criteria, for which the panel methodologist assigned a level of evidence based on standardized grading adopted by the American Academy of Ophthalmology. One, 15, and 16 studies were rated as providing level I, II, and III evidence, respectively. RESULTS All follow-up, IOP, and medication data listed are weighted means. In general, the studies reported on patients using few glaucoma medications (1.5-1.9 before surgery among the different diagnoses). For POAG, 9 studies (total, 461 patients; follow-up, 17 months) showed that phacoemulsification reduced IOP by 13% and glaucoma medications by 12%. For PXG, 5 studies (total, 132 patients; follow-up, 34 months) showed phacoemulsification reduced IOP by 20% and glaucoma medications by 35%. For chronic PACG, 12 studies (total, 495 patients; follow-up, 16 months) showed phacoemulsification reduced IOP by 30% and glaucoma medications by 58%. Patients with acute PACG (4 studies; total, 119 patients; follow-up, 24 months) had a 71% reduction from presenting IOP and rarely required long-term glaucoma medications when phacoemulsification was performed soon after medical reduction of IOP. Trabeculectomy after phacoemulsification was uncommon; the median rate reported within 6 to 24 months of follow-up in patients with controlled POAG, PXG, or PACG was 0% and was 7% in patients with uncontrolled chronic PACG. CONCLUSIONS Phacoemulsification typically results in small, moderate, and marked reductions of IOP and medications for patients with POAG, PXG, and PACG, respectively, and using 1 to 2 medications before surgery. Trabeculectomy within 6 to 24 months after phacoemulsification is rare in such patients. However, reports on its effects in eyes with advanced disease or poor IOP control before surgery are few, particularly for POAG and PXG.


American Journal of Ophthalmology | 1998

The effects of cataract extraction on the visual field of eyes with chronic open-angle glaucoma

Philip P. Chen; Donald L. Budenz

PURPOSE To investigate effects of cataract extraction and intraocular lens placement on the visual field of eyes with chronic open-angle glaucoma. METHODS A retrospective review was conducted of 41 eyes of 41 patients with visually significant cataract and chronic open-angle glaucoma who had undergone automated static perimetry within 6 months before and 6 months after phacoemulsification with intraocular lens placement. RESULTS Comparison of preoperative and postoperative testing showed that the mean visual acuity, foveal threshold, and mean deviation improved significantly (P < .0001), while the mean pattern standard deviation and corrected pattern standard deviation worsened significantly (P < or = .03). Eyes not receiving miotics preoperatively did not have a significant postoperative change in the mean pattern and corrected pattern standard deviations. Increasing severity of glaucoma-related visual field loss was significantly associated with less improvement in the postoperative mean deviation (P = .0001). Only two (5%) of 41 eyes had worsening of the mean deviation of 1.0 dB or greater. The foveal threshold improved more than the mean deviation did but not significantly more, except in eyes with severe visual field loss. CONCLUSIONS Cataract extraction resulted in statistically significant improvement in visual acuity and foveal threshold in most eyes with glaucoma. In eyes with mild or moderate glaucoma-related damage, the mean deviation often improved significantly after cataract extraction, but improvement was less predictable in eyes with severe or end-stage damage. The pattern and corrected pattern standard deviations may be reliable indicators of glaucoma-related damage in eyes with cataract but without constricted pupils.


Ophthalmology | 2002

Learning effects among perimetric novices in frequency doubling technology perimetry

Peter J Joson; Maria E.G Kamantigue; Philip P. Chen

PURPOSE To investigate learning effects, including improvements in reliability indices, in frequency doubling technology (FDT) perimetry in subjects without glaucoma who have not undergone previous automated perimetry. DESIGN Prospective consecutive case series. PARTICIPANTS Eighty-one normal subjects. METHODS Normal subjects were recruited from the University of Washington Eye Clinic who had no history of automated visual field testing. All eyes underwent complete ophthalmic examination. The C-20-5 screening mode of FDT perimetry (Zeiss-Humphrey, San Leandro, CA) was performed after appropriate instruction, including a demonstration of the frequency doubling phenomenon. If any abnormal areas were identified or there were greater than 33% fixation losses or false-positive results, then the test was readministered up to three times or until a normal result was returned. MAIN OUTCOME MEASURES Normal FDT test. RESULTS The mean age was 54.8 years (range, 19-94). Sixty-nine subjects (85.2%) returned a normal test after a single test administration. Nine subjects (11.1%) required two administrations, and two subjects (2.5%) required three or more administrations to return a normal test. One subject still tested unreliably after four tests. The number or severity of abnormal locations did not predict the number of trials necessary to overcome learning effects. Fixation loss was the most common reliability problem. Subjects who demonstrated learning effects did not differ significantly in age, visual acuity, refraction, or test time from those who did not. CONCLUSIONS Some perimetric novices demonstrate learning effects in C-20-5 screening-mode FDT perimetry. Learning effects in FDT perimetry must be considered during screening for glaucoma or other ocular disease.


Ophthalmology | 2013

Evaluation of the Anterior Chamber Angle in Glaucoma: A Report by the American Academy of Ophthalmology

Scott D. Smith; Kuldev Singh; Shan C. Lin; Philip P. Chen; Teresa C. Chen; Brian A. Francis; Henry D. Jampel

OBJECTIVE To assess the published literature pertaining to the association between anterior segment imaging and gonioscopy and to determine whether such imaging aids in the diagnosis of primary angle closure (PAC). METHODS Literature searches of the PubMed and Cochrane Library databases were last conducted on July 6, 2011. The searches yielded 371 unique citations. Members of the Ophthalmic Technology Assessment Committee Glaucoma Panel reviewed the titles and abstracts of these articles and selected 134 of possible clinical significance for further review. The panel reviewed the full text of these articles and identified 79 studies meeting the inclusion criteria, for which the panel methodologist assigned a level of evidence based on a standardized grading scheme adopted by the American Academy of Ophthalmology. Three, 70, and 6 studies were rated as providing level I, II, and III evidence, respectively. RESULTS Quantitative and qualitative parameters defined from ultrasound biomicroscopy (UBM), anterior segment optical coherence tomography (OCT), Scheimpflug photography, and the scanning peripheral anterior chamber depth analyzer (SPAC) demonstrate a strong association with the results of gonioscopy. There is substantial variability in the type of information obtained from each imaging method. Imaging of structures posterior to the iris is possible only with UBM. Direct imaging of the anterior chamber angle (ACA) is possible using UBM and OCT. The ability to acquire OCT images in a completely dark environment allows greater sensitivity in detecting eyes with appositional angle closure. Noncontact imaging using OCT, Scheimpflug photography, or SPAC makes these methods more attractive for large-scale PAC screening than contact imaging using UBM. CONCLUSIONS Although there is evidence suggesting that anterior segment imaging provides useful information in the evaluation of PAC, none of these imaging methods provides sufficient information about the ACA anatomy to be considered a substitute for gonioscopy. Longitudinal studies are needed to validate the diagnostic significance of the parameters measured by these instruments for prospectively identifying individuals at risk for PAC. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

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Mark Slabaugh

University of Washington

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Divakar Gupta

University of Washington

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Donald L. Budenz

University of North Carolina at Chapel Hill

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Chieh-Li Chen

University of Washington

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Joanne C Wen

University of Washington

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