Asymmetric organelle positioning during epithelial polarization of C. elegans intestinal cells.

While the epithelial cell cortex displays profound asymmetries in protein distribution and morphology along the apico-basal axis, the extent to which the cytoplasm is similarly polarized within epithelial cells remains relatively unexplored. We show that cytoplasmic organelles within C. elegans embryonic intestinal cells develop extensive apico-basal polarity at the time they establish cortical asymmetry. Nuclei and conventional endosomes, including early endosomes, late endosomes, and lysosomes, become polarized apically. Lysosome-related gut granules, yolk platelets, and lipid droplets become basally enriched. Removal of par-3 activity does not disrupt organelle positioning, indicating that cytoplasmic apico-basal asymmetry is independent of the PAR polarity pathway. Blocking the apical migration of nuclei leads to the apical positioning of gut granules and yolk platelets, whereas the asymmetric localization of conventional endosomes and lipid droplets is unaltered. This suggests that nuclear positioning organizes some, but not all, cytoplasmic asymmetries in this cell type. We show that gut granules become apically enriched when WHT-2 and WHT-7 function is disrupted, identifying a novel role for ABCG transporters in gut granule positioning during epithelial polarization. Analysis of WHT-2 and WHT-7 ATPase mutants is consistent with a WHT-2/WHT-7 heterodimer acting as a transporter in gut granule positioning. In wht-2(-) mutants, the polarized distribution of other organelles is not altered and gut granules do not take on characteristics of conventional endosomes that could have explained their apical mispositioning. During epithelial polarization wht-2(-) gut granules exhibit a loss of the Rab32/38 family member GLO-1 and ectopic expression of GLO-1 is sufficient to rescue the basal positioning of wht-2(-) and wht-7(-) gut granules. Furthermore, depletion of GLO-1 causes the mislocalization of the endolysosomal RAB-7 to gut granules and RAB-7 drives the apical mispositioning of gut granules when GLO-1, WHT-2, or WHT-7 function is disrupted. We suggest that ABC transporters residing on gut granules can regulate Rab dynamics to control organelle positioning during epithelial polarization.

Postoperative Complications in the Primary Tube Versus Trabeculectomy Study During 5 Years of Follow-up.

PURPOSE: To describe postoperative complications encountered in the Primary Tube Versus Trabeculectomy (PTVT) Study during 5 years of follow-up. DESIGN: Multicenter randomized clinical trial. PARTICIPANTS: A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group. METHODS: Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes). MAIN OUTCOME MEASURES: Surgical complications, reoperations for complications, visual acuity, and cataract progression. RESULTS: Early postoperative complications occurred in 24 patients (19%) in the tube group and 40 patients (34%) in the trabeculectomy group (P = 0.013). Late postoperative complications developed in 27 patients (22%) in the tube group and 32 patients (27%) in the trabeculectomy group (P = 0.37). Serious complications producing vision loss and/or requiring a reoperation were observed in 3 patients (2%) in the tube group and 9 patients (8%) in the trabeculectomy group (P = 0.11). Cataract progression was seen in 65 patients (52%) in the tube group and 52 patients (44%) in the trabeculectomy group (P = 0.30). Surgical complications were not associated with a higher rate of treatment failure (P = 0.61), vision loss (P = 1.00), or cataract progression (P = 0.77) CONCLUSIONS: A large number of surgical complications were observed in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was higher following trabeculectomy with MMC than with tube shunt surgery. The rates of late postoperative complications, serious complications, and cataract progression were similar with both surgical procedures after 5 years of follow-up. Surgical complications did not increase the risk of treatment failure, vision loss, or cataract progression.

Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 5 Years of Follow-up.

PURPOSE: To report 5-year treatment outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study. DESIGN: Multicenter randomized clinical trial. PARTICIPANTS: A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group. METHODS: Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC) (0.4 mg/ml for 2 minutes). MAIN OUTCOME MEASURES: The primary outcome measure was the rate of surgical failure, defined as intraocular pressure (IOP) > 21 mmHg or reduced < 20% from baseline, IOP ≤ 5 mmHg, reoperation for glaucoma, or loss of light perception. Secondary outcome measures included IOP, glaucoma medical therapy, and visual acuity. RESULTS: The cumulative probability of failure after 5 years of follow-up was 42% in the tube group and 35% in the trabeculectomy group (P = 0.21; hazard ratio = 1.31; 95% confidence interval = 0.86-2.01). At 5 years, IOP (mean ± standard deviation) was 13.4 ± 3.5 mmHg in the tube group and 13.0 ± 5.2 mmHg in the trabeculectomy group (P = 0.52), and the number of glaucoma medications (mean ± standard deviation) was 2.2 ± 1.3 in the tube group and 1.3 ± 1.4 in the trabeculectomy group (P < 0.001). CONCLUSIONS: Trabeculectomy with MMC and tube shunt surgery produced similar IOPs after 5 years of follow-up in the PTVT Study, but fewer glaucoma medications were required after trabeculectomy. No significant difference in the rate of surgical failure was observed between the 2 surgical procedures at 5 years.

Central Corneal Thickness in the Ocular Hypertension Treatment Study (OHTS).

OBJECTIVE: Central corneal thickness influences intraocular pressure (IOP) measurement. We examined the central corneal thickness of subjects in the Ocular Hypertension Treatment Study (OHTS) and determined if central corneal thickness is related to race. DESIGN: Cross-sectional study. PARTICIPANTS: One thousand three hundred one OHTS subjects with central corneal thickness measurements. INTERVENTION: Central corneal thickness was determined with ultrasonic pachymeters of the same make and model at all clinical sites of the OHTS. MAIN OUTCOME MEASURES: Correlation of mean central corneal thickness with race, baseline IOP, refraction, age, gender, systemic hypertension, and diabetes. RESULTS: Mean central corneal thickness was 573.0 ± 39.0 µm. Twenty-four percent of the OHTS subjects had central corneal thickness > 600 µm. Mean central corneal thickness for African American subjects (555.7 ± 40.0 µm; n = 318) was 23 µm thinner than for white subjects (579.0 ± 37.0 µm; P < 0.0001). Other factors associated with greater mean central corneal thickness were younger age, female gender, and diabetes. CONCLUSIONS: OHTS subjects have thicker corneas than the general population. African American subjects have thinner corneas than white subjects in the study. The effect of central corneal thickness may influence the accuracy of applanation tonometry in the diagnosis, screening, and management of patients with glaucoma and ocular hypertension.

Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 3 Years of Follow-up.

PURPOSE: To report 3-year results of the Primary Tube Versus Trabeculectomy (PTVT) Study. DESIGN: Unmasked multicenter randomized clinical trial. PARTICIPANTS: Two hundred forty-two eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 in the tube group and 117 in the trabeculectomy group. METHODS: Patients were enrolled at 16 clinical centers and were assigned randomly to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC; 0.4 mg/ml for 2 minutes). MAIN OUTCOME MEASURES: The primary outcome measure was the rate of surgical failure, defined as intraocular pressure (IOP) of more than 21 mmHg or reduced less than 20% from baseline, IOP of 5 mmHg or less, reoperation for glaucoma, or loss of light perception vision. Secondary outcome measures included IOP, glaucoma medical therapy, visual acuity, and surgical complications. RESULTS: The cumulative probability of failure after 3 years of follow-up was 33% in the tube group and 28% in the trabeculectomy group (P = 0.17; hazard ratio, 1.39; 95% confidence interval, 0.9-2.2). Mean ± standard deviation IOP was 14.0±4.2 mmHg in the tube group and 12.1±4.8 mmHg in the trabeculectomy group at 3 years (P = 0.008), and the number of glaucoma medications was 2.1±1.4 in the tube group and 1.2±1.5 in the trabeculectomy group (P < 0.001). Serious complications requiring reoperation or producing loss of 2 or more Snellen lines developed in 3 patients (2%) in the tube group and 9 patients (8%) in the trabeculectomy group (P = 0.11). CONCLUSIONS: There was no significant difference in the rate of surgical failure between the 2 surgical procedures at 3 years. Trabeculectomy with MMC achieved lower IOP with use of fewer glaucoma medications compared with tube shunt surgery after 3 years of follow-up in the PTVT Study. Serious complications producing vision loss or requiring reoperation occurred with similar frequency after both surgical procedures.

Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 1 Year of Follow-up.

PURPOSE: To report 1-year treatment outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study. DESIGN: Multicenter, randomized clinical trial. PARTICIPANTS: Two hundred forty-two eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 in the tube group and 117 in the trabeculectomy group. METHODS: Patients were enrolled at 16 clinical centers and assigned randomly to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC; 0.4 mg/ml for 2 minutes). MAIN OUTCOME MEASURES: Intraocular pressure (IOP), glaucoma medical therapy, visual acuity, visual fields, surgical complications, and failure (IOP of more than 21 mmHg or reduced by less than 20% from baseline, IOP of 5 mmHg or less, reoperation for glaucoma, or loss of light perception vision). RESULTS: The cumulative probability of failure during the first year of follow-up was 17.3% in the tube group and 7.9% in the trabeculectomy group (P = 0.01; hazard ratio, 2.59; 95% confidence interval, 1.20-5.60). Mean ± standard deviation IOP was 13.8±4.1 mmHg in the tube group and 12.4±4.4 mmHg in the trabeculectomy group at 1 year (P = 0.01), and the number of glaucoma medications was 2.1±1.4 in the tube group and 0.9±1.4 in the trabeculectomy group (P < 0.001). Postoperative complications developed in 36 patients (29%) in the tube group and 48 patients (41%) in the trabeculectomy group (P = 0.06). Serious complications requiring reoperation or producing a loss of 2 Snellen lines or more occurred in 1 patient (1%) in the tube group and 8 patients (7%) in the trabeculectomy group (P = 0.03). CONCLUSIONS: Trabeculectomy with MMC had a higher surgical success rate than tube shunt implantation after 1 year in the PTVT Study. Lower IOP with use of fewer glaucoma medications was achieved after trabeculectomy with MMC compared with tube shunt surgery during the first year of follow-up. The frequency of serious complications producing vision loss or requiring reoperation was lower after tube shunt surgery relative to trabeculectomy with MMC.

Oral Memantine for the Treatment of Glaucoma: Design and Results of 2 Randomized, Placebo-Controlled, Phase 3 Studies.

PURPOSE: To evaluate the effectiveness and safety of oral memantine as a potential neuroprotective agent in open-angle glaucoma (OAG) at risk for progression. DESIGN: Two randomized, double-masked, placebo-controlled, parallel-group, multicenter, 48-month studies identically designed, initiated 1 year apart, and completed in 2006. Protocol amendments included a 1-year extension (first study) and change in primary endpoint and analysis (second study). PARTICIPANTS: Patients (2298 total) with bilateral OAG; glaucomatous optic disc damage and visual field loss in 1 eye; glaucomatous optic disc damage and/or visual field loss in the contralateral eye (at screening), topically treated or untreated intraocular pressure (IOP) of 21 mmHg or less (at baseline); and at risk of glaucomatous progression (per prespecified criteria). METHODS: Patients were randomized 3:2:2 to receive memantine 20 mg, memantine 10 mg, or placebo tablets daily. Glaucomatous progression was assessed in the intent-to-treat population by full-threshold standard automated perimetry (SAP), frequency doubling technology (FDT), and stereoscopic optic disc photographs, standardized by quality control assessment at centralized reading centers. Safety evaluations included adverse events (AEs), best-corrected visual acuity, biomicroscopy, IOP, and ophthalmoscopy. Efficacy data from each study were analyzed per protocol. Pooled analyses of efficacy and safety data were also performed. MAIN OUTCOME MEASURES: The predefined primary efficacy measure was glaucomatous visual field progression, as measured by SAP. Additional efficacy measures included glaucomatous progression of visual field (FDT) and optic nerve damage (stereoscopic optic disc photographs). RESULTS: The proportion of patients who completed the studies was similar among groups (80%-83%). Compared with placebo, daily treatment with memantine 10 mg or 20 mg for 48 months did not delay glaucomatous progression significantly in the individual studies and pooled analyses. The pooled risk reduction ratio (95% confidence interval) assessed by SAP was -0.13 (-0.40, 0.09) and -0.17 (-0.46, 0.07) for memantine 10 mg and 20 mg, respectively. Results were similar per FDT and stereoscopic optic disc photographs. The most common AEs leading to treatment discontinuations were dizziness, headache, fatigue, and nausea. CONCLUSIONS: With technologies available when the studies were conducted, daily treatment with memantine over 48 months was not shown to prevent glaucomatous progression in this patient population.

Six-Month Intraocular Pressure Reduction with a Topical Bimatoprost Ocular Insert: Results of a Phase II Randomized Controlled Study.

PURPOSE: Improving adherence to manage elevated intraocular pressure (IOP) remains an unmet need. A topical bimatoprost ocular insert was compared with twice-daily timolol eye drops in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT) treated for 6 months. DESIGN: Parallel-arm, multicenter, double-masked, randomized, controlled trial. PARTICIPANTS: One hundred thirty adult OAG or OHT patients. METHODS: Eligible patients were randomized 1:1 to receive a bimatoprost insert plus artificial tears twice daily or a placebo insert plus timolol (0.5% solution) twice daily for 6 months after a screening washout period. Diurnal IOP measurements (at 0, 2, and 8 hours) were obtained at baseline; weeks 2, 6, and 12; and months 4, 5, and 6. Key eligibility included washout IOP of 23 mmHg or more at time 0, IOP of 20 mmHg or more at 2 and 8 hours, and IOP of 34 mmHg or less at all time points; no prior incisional surgery for OAG or OHT; and no known nonresponders to prostaglandins. MAIN OUTCOME MEASURES: The primary efficacy end point examined the difference in mean change from baseline in diurnal IOPs (point estimate, 95% confidence interval) across 9 coprimary end points at weeks 2, 6, and 12 comparing the bimatoprost arm with the timolol arm using a noninferiority margin of 1.5 mmHg. Secondary end points were diurnal IOP measurements at months 4, 5, and 6 and adverse events (AEs). RESULTS: A mean reduction from baseline IOP of -3.2 to -6.4 mmHg was observed for the bimatoprost group compared with -4.2 to -6.4 mmHg for the timolol group over 6 months. The study met the noninferiority definition at 2 of 9 time points but was underpowered for the observed treatment effect. Adverse events were consistent with bimatoprost or timolol exposure; no unexpected ocular AEs were observed. Primary retention rate of the insert was 88.5% of patients at 6 months. CONCLUSIONS: Clinically relevant reduction in mean IOP was observed over 6 months with a bimatoprost ocular insert and seems to be safe and well tolerated. The topically applied bimatoprost insert may provide an alternative to daily eye drops to improve adherence, consistency of delivery, and reduction of elevated IOP.

Measuring intraocular pressure.

PURPOSE OF REVIEW: Tonometry is undergoing a long-overdue renaissance. Goldmann applanation tonometry (GAT) is 50-year-old technology. Although GAT is considered a 'reference standard', it has many limitations and confounders. This review compares GAT to some of the newer technologies that have recently been commercialized or are in development. RECENT FINDINGS: Dynamic contour tonometry is fairly cornea-independent, but requires technical skill to carry out. Rebound tonometry requires no anesthetic and is particularly useful in children. The ocular response analyzer quantifies corneal biomechanical factors and provides other useful measures relevant to glaucoma risk. A transpalpebral tonometer that claims to measure intraocular pressure (IOP) through the closed eyelid has been introduced, but studies comparing it to conventional tonometers suggest it is too unreliable for routine use. Various new technologies including IOP-sensing contact lenses and implantable sensors are in clinical evaluation. SUMMARY: There is no perfect tonometer, and clinicians must choose which to use in their daily practice, balancing accuracy, precision, convenience, and cost. Clinicians should recognize that a single IOP measurement is but an often error-prone snapshot of a widely varying physiologic parameter. IOP data should only be used in the context of the overall clinical picture.

Geographic Information System Mapping of Social Risk Factors and Patient Outcomes of Pediatric Glaucoma.

PURPOSE: This study aimed to use Geographic Information System (GIS) mapping to present the geospatial distribution of visual outcomes and sociodemographic risk factors of a cohort of pediatric glaucoma patients. DESIGN: Retrospective cohort study. SUBJECTS: 233 eyes of 177 pediatric glaucoma patients treated at UC Davis Medical Center. METHODS: We reviewed the medical records of pediatric patients (aged less than 18 years) with the diagnosis of pediatric glaucoma or any adult with a prior history of pediatric glaucoma at UC Davis Medical Center from 2001 to 2019. Patient sociodemographic information and ocular health data were recorded. Patients were mapped to their residential home 3-digit zip code prefix using ArcGIS software to generate geographic representations of the pediatric glaucoma database. Statistical analyses were performed to identify significant risk factors to poor visual outcome. MAIN OUTCOME MEASURES: The primary outcome was the patient's final visual acuity (VA), defined as a binary variable based on the World Health Organization's criteria: good VA (better than 20/200) or poor VA (worse than 20/200). The secondary outcome was final intraocular pressure (IOP) at patients' final follow-ups. Risk factors for poor vision and higher IOP were assessed. RESULTS: At final follow-up, 65 eyes (27.9%) had poor vision and 168 eyes (72.1%) had good vision. In the multivariate analysis, the odds ratio of good VA decreased by 4% for every 1 mmHg increase in initial IOP (P = 0.03), and the odds of good VA decreased by 6% for every year increase in age (P = 0.04). Patients with private insurance had a 3.5 mmHg lower final IOP than those with Medicaid (P = 0.004). Travel distance was not associated with a poorer visual outcome. CONCLUSIONS: Private insurance patients had lower final IOP than Medicaid patients. Age and initial IOP were significant negative predictors of VA. Despite travel distance appearing to be associated with poorer visual outcomes by GIS mapping, it was not statistically significant. Geographic information system mapping of patient outcomes is an innovative way to visualize patient demographics and risk factors. Geographic information system may prove particularly useful in larger nationwide disease and surgical registries, especially for rare disorders like pediatric glaucoma. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

The Wholesome Foods Approach to Trabeculectomy Wet Lab Training.

Purpose In an era when trabeculectomy surgeries in the United States are on the decline, ophthalmology residents may have limited opportunities to practice surgical techniques critical to success. However, key steps of trabeculectomy surgery can be introduced in a wet laboratory using a simple surgical model based on food items. Methods A fresh lime and chicken parts with skin, purchased from a grocery store, were utilized to practice trabeculectomy surgery. The white rind of a lime was used as a surrogate for human sclera and was incised to create a trabeculectomy flap. The flap was then successfully sewn down with 10-0 nylon suture using an operating microscope. The skin of the chicken part was used to re-create a fornix-based and limbus-based conjunctival incision, which was then sutured closed using 6-0 Vicryl suture. A survey of wet laboratory participants was conducted to assess the feasibility and efficacy of this technique. Results Survey respondents were divided into two groups, those who had performed ≥40 incisional glaucoma surgeries and those who had performed <40. Both groups rated the simulation a 4 (mode) out of 5 in terms of how well it prepared them for glaucoma surgery on a human eye and how well the materials replicated human tissue, with 1 being not at all and 5 being very well. Similarly, both groups rated ease of setup and material acquisition a 1 out of 5, 1 being not difficult at all and 5 being extremely difficult. Also, 93.5% of the survey respondents recommended implementing this training model at other teaching hospitals, and none of the respondents recommended against it. Conclusion This trabeculectomy teaching model is inexpensive, clean, and safe, and it provides a reasonably realistic substrate for surgical practice. It does not require cadaver or animal eyes, and no fixatives are needed, thus minimizing the risk of contact with biohazardous materials. Wet laboratory materials are easy to obtain, making this a practical model for practicing glaucoma surgery in both westernized and developing countries.

Preparing the Ocular Surface for a Boston Keratoprosthesis Type 1 Through En Bloc Minor Salivary Gland Transplantation and Mucous Membrane Grafting in End-Stage Stevens-Johnson Syndrome.

PURPOSE: This case describes the successful visual restoration of a patient with end-stage Stevens-Johnson syndrome (SJS) with a severely keratinized ocular surface. METHODS: This study is a case report. RESULTS: A 67-year-old man with SJS secondary to allopurinol sought visual rehabilitation options. His ocular surface was severely compromised from sequelae of chronic SJS, leaving him with light perception vision bilaterally. The left eye was completely keratinized with severe ankyloblepharon. The right eye had failed penetrating keratoplasty, limbal stem cell deficiency, and a keratinized ocular surface. The patient declined both a Boston type 2 keratoprosthesis and a modified osteo-odonto keratoprosthesis. Therefore, a staged approach was pursued with (1) systemic methotrexate to control ocular surface inflammation, (2) minor salivary gland transplant to increase ocular surface lubrication, (3) lid margin mucous membrane graft to reduce keratinization, and finally, (4) Boston type 1 keratoprosthesis for visual restoration. After minor salivary gland transplant and mucous membrane graft, the Schirmer score improved from 0 mm to 3 mm with improvement in ocular surface keratinization. This approach successfully restored the vision to 20/60, and the patient has retained the keratoprosthesis for over 2 years. CONCLUSIONS: Sight restoration options are limited in patients with end-stage SJS with a keratinized ocular surface, aqueous and mucin deficiency, corneal opacification, and limbal stem cell deficiency. This case demonstrates successful ocular surface rehabilitation and vision restoration in such a patient through a multifaceted approach that resulted in successful implantation and retention of a Boston type 1 keratoprosthesis.

Adjusting intraocular pressure for central corneal thickness does not improve prediction models for primary open-angle glaucoma.

PURPOSE: To determine if the accuracy of the baseline prediction model for the development of primary open-angle glaucoma (POAG) in patients with ocular hypertension can be improved by correcting intraocular pressure (IOP) for central corneal thickness (CCT). DESIGN: Reanalysis of the baseline prediction model for the development of POAG from the Ocular Hypertension Treatment Study (OHTS) substituting IOP adjusted for CCT using 5 different correction formulae for unadjusted IOP. PARTICIPANTS: A total of 1433 of 1636 participants randomized to OHTS who had complete baseline data for factors in the prediction model: age, IOP, CCT, vertical cup-to-disc ratio (VCDR), and pattern standard deviation (PSD). METHODS: Reanalysis of the prediction model for the risk of developing POAG using the same baseline variables (age, IOP, CCT, VCDR, and PSD) except that IOP was adjusted for CCT using correction formulae. A separate Cox proportional hazards model was run using IOP adjusted for CCT by each of the 5 formulae published to date. Models were run including and excluding CCT. MAIN OUTCOME MEASURES: Predictive accuracy of each Cox proportional hazards model was assessed using the c-statistic and calibration chi-square. RESULTS: C-statistics for prediction models that used IOP adjusted for CCT by various formulas ranged from 0.75 to 0.77, no better than the original prediction model (0.77) that did not adjust IOP for CCT. Calibration chi-square was acceptable for all models. Baseline IOP, whether adjusted for CCT or not, was statistically significant in all models including those with CCT in the same model. The CCT was statistically significant in all models including those with IOP adjusted for CCT in the same model. CONCLUSIONS: The calculation of individual risk for developing POAG in ocular hypertensive individuals is simpler and equally accurate using IOP and CCT as measured, rather than applying an adjustment formula to correct IOP for CCT.

Reduction in intraocular pressure after cataract extraction: the Ocular Hypertension Treatment Study.

PURPOSE: To determine the change in intraocular pressure (IOP) after cataract extraction in the observation group of the Ocular Hypertension Treatment Study. DESIGN: Comparative case series. PARTICIPANTS: Forty-two participants (63 eyes) who underwent cataract surgery in at least 1 eye during the study and a control group of 743 participants (743 eyes) who did not undergo cataract surgery. METHODS: We defined the "split date" as the study visit date at which cataract surgery was reported in the cataract surgery group and a corresponding date in the control group. Preoperative IOP was defined as the mean IOP of up to 3 visits before the split date. Postoperative IOP was the mean IOP of up to 3 visits including the split date (0, 6, and 12 months' with "0 months" equaling the split date). In both groups, we censored data after initiation of ocular hypotensive medication or glaucoma surgery of any kind. MAIN OUTCOME MEASURES: Difference in preoperative and postoperative IOP. RESULTS: In the cataract group, postoperative IOP was significantly lower than the preoperative IOP (19.8 ± 3.2 mmHg vs. 23.9 ± 3.2 mmHg; P<0.001). The postoperative IOP remained lower than the preoperative IOP for at least 36 months. The average decrease in postoperative IOP from preoperative IOP was 16.5%, and 39.7% of eyes had postoperative IOP ≥ 20% below preoperative IOP. A greater reduction in postoperative IOP occurred in the eyes with the highest preoperative IOP. In the control group, the corresponding mean IOPs were 23.8 ± 3.6 before the split date and 23.4 ± 3.9 after the split date. CONCLUSIONS: Cataract surgery decreases IOP in patients with ocular hypertension over a long period of time.