Incidence and remission of post-surgical cystoid macular edema following cataract surgery in eyes with intraocular inflammation.

PURPOSE: To evaluate the incidence, remission and relapse of post-surgical cystoid macular edema (PCME) following cataract surgery in inflammatory eye disease. METHODS: A total of 1859 eyes that had no visually significant macular edema prior to cataract surgery while under tertiary uveitis management were included. Standardized retrospective chart review was used to gather clinical data. Univariable and multivariable logistic regression models with adjustment for inter-eye correlations were performed. RESULTS: PCME causing VA 20/50 or worse was reported in 286 eyes (15%) within 6 months of surgery. Adults age 18-64 years as compared to children (adjusted Odds ratio (aOR) 2.42, for ages 18-44 and aOR 1.93 for ages 45-64, overall p = 0.02); concurrent use of systemic immunosuppression (conventional aOR 1.53 and biologics aOR 2.68, overall p =0.0095); pre-operative VA 20/50 or worse (overall p <0.0001); cataract surgery performed before 2000 (overall p=0.03) and PMCE in fellow eye (aOR 3.04, p=0.0004) were associated with development of PCME within 6 months of cataract surgery. PCME resolution was seen in 81% of eyes at 12 months and 91% of eyes at 24 months. CME relapse was seen in 12% eyes at 12 months and 19% eyes at 24 months. CONCLUSIONS: PCME occurs frequently in uveitic eyes undergoing cataract surgery, however, most resolve within a year. CME recurrences likely are due to the underlying disease process and not relapses of PCME.

Posterior capsular opacification and YAG laser capsulotomy in uveitis patients following cataract surgery.

OBJECTIVE: To evaluate the incidence of visually significant posterior capsule opacification (PCO with visual acuity ≤20/50) and the incidence of Nd:YAG laser capsulotomy in the year following cataract surgery for uveitic eyes. METHOD: Patients were identified from the Systemic Immunosuppressive Therapy for Eye Diseases (SITE) Cohort Study using a standardized chart review process. RESULTS: Among 1,855 uveitic eyes of 1,370 patients who had undergone cataract surgery, visually significant PCO occurred in 297 eyes (16%), and YAG laser capsulotomy was done in 407 eyes (22%) within the first year following surgery. Higher odds of developing 20/50 visual acuity attributed to PCO were noted in children and young adults compared with adults older than 65 years of age (overall p = 0.03). Poorer preoperative visual acuity (overall p = 0.0069) and postoperative inflammation (odds ratio [OR] = 1.83; 95% CI, 1.37-2.45; p < 0.0001) were associated with PCO incidence. In multivariable analysis, risk factors for YAG laser capsulotomy were younger age groups compared with those older than 65 years of age at the time of surgery (adjusted OR [aOR] = 1.90-2.24; 95% CI, 1.90-2.24; overall p = 0.0007), female sex (aOR = 1.37; 95% CI, 1.03-1.82; p = 0.03), postoperative active inflammation (aOR = 165; 95% CI, 1.27-2.16; overall p < 0.0001), extracapsular cataract extraction compared with phacoemulsification (aOR = 1.70; 95% CI, 1.17-2.47; overall p < 0.0001), and insertion of an intraocular lens (aOR = 4.60; 95% CI, -2.29-9.25; p < 0.0001). Black race was associated with lower YAG laser capsulotomy incidence than Whites (aOR = 0.36; 95% CI, 0.24-0.52; overall p < 0.0001). CONCLUSIONS: Vision-reducing (≤20/50) PCO is common, occurring in about one sixth of uveitic eyes within 1 year of cataract surgery; a higher number (22%) of eyes underwent YAG laser capsulotomy within the first year. Age and postoperative inflammation following cataract surgery are the variables most associated with the incidence of visually significant PCO and YAG laser capsulotomy.

Use of Immunosuppression and the Risk of Subsequent Overall or Cancer Mortality.

PURPOSE: To determine the incidence of all-cause and cancer mortality (CM) in association with immunosuppression. DESIGN: Retrospective cohort study at ocular inflammatory disease (OID) subspecialty centers. We harvested exposure and covariate data retrospectively from clinic inception (earliest in 1979) through 2010 inclusive. Then we ascertained overall and cancer-specific mortalities by National Death Index linkage. We constructed separate Cox models to evaluate overall and CM for each class of immunosuppressant and for each individual immunosuppressant compared with person-time unexposed to any immunosuppression. PARTICIPANTS: Patients with noninfectious OID, excluding those with human immunodeficiency infection or preexisting cancer. METHODS: Tumor necrosis factor (TNF) inhibitors (mostly infliximab, adalimumab, and etanercept); antimetabolites (methotrexate, mycophenolate mofetil, azathioprine); calcineurin inhibitors (cyclosporine); and alkylating agents (cyclophosphamide) were given when clinically indicated in this noninterventional cohort study. MAIN OUTCOME MEASURES: Overall mortality and CM. RESULTS: Over 187 151 person-years (median follow-up 10.0 years), during which 15 938 patients were at risk for mortality, we observed 1970 deaths, 435 due to cancer. Both patients unexposed to immunosuppressants (standardized mortality ratio [SMR] = 0.95, 95% confidence interval [CI], 0.90-1.01) and those exposed to immunosuppressants but free of systemic inflammatory diseases (SIDs) (SMR = 1.04, 95% CI, 0.95-1.14) had similar mortality risk to the US population. Comparing patients exposed to TNF inhibitors, antimetabolites, calcineurin inhibitors, and alkylating agents with patients not exposed to any of these, we found that overall mortality (adjusted hazard ratio [aHR] = 0.88, 0.89, 0.90, 1.11) and CM (aHR = 1.25, 0.89, 0.86, 1.23) were not significantly increased. These results were stable in sensitivity analyses whether excluding or including patients with SID, across 0-, 3-, or 5-year lags and across quartiles of immunosuppressant dose and duration. CONCLUSIONS: Our results, in a cohort where the indication for treatment was proven unassociated with mortality risk, found that commonly used immunosuppressants-especially the antimetabolites methotrexate, mycophenolate mofetil, and azathioprine; the TNF inhibitors adalimumab and infliximab, and cyclosporine-were not associated with increased overall and CM over a median cohort follow-up of 10.0 years. These results suggest the safety of these agents with respect to overall and CM for patients treated with immunosuppression for a wide range of inflammatory diseases. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Incidence of and Risk Factors for Cataract in Anterior Uveitis.

PURPOSE: To estimate the incidence/risk factors for cataract in noninfectious anterior uveitis. DESIGN: Retrospective multicenter cohort study (6 US tertiary uveitis sites, 1978-2010). METHODS: Data were harvested by trained expert reviewers, using protocol-driven review of experts' charts. We studied cataract incidence-newly reduced visual acuity worse than 20/40 attributed to cataract; or incident cataract surgery-in 3923 eyes of 2567 patients with anterior uveitis. RESULTS: Cataract developed in 507 eyes (54/1000 eye-years, 95% CI 49-59). Time-updated risk factors associated with cataract included older age (≥65 vs <18 years: adjusted hazard ratio [aHR] 5.04, 95% CI 3.04-8.33), higher anterior chamber cell grade (P(trend)=0.001), prior incisional glaucoma surgery (aHR 1.86, 95% CI 1.10-3.14), band keratopathy (aHR 2.23, 95% CI 1.47-3.37), posterior synechiae (aHR 3.71, 95% CI 2.83-4.87), and elevated intraocular pressure ≥30 vs 6-20 mm Hg (aHR 2.57, 95% CI 1.38-4.77). Primary acute (aHR 0.59, 95% CI 0.30-1.15) and recurrent acute (aHR 0.74, 95% CI 0.55-0.98) had lower cataract risk than chronic anterior uveitis. Higher-dose prednisolone acetate 1%-equivalent use (≥2 drops/day) was associated with >2-fold higher cataract risk in eyes with anterior chamber cell grades 0.5+ or lower but was not associated with higher cataract risk in the presence of anterior chamber cells of grade 1+ or higher. CONCLUSIONS: Cataract complicates anterior uveitis in ∼5.4/100 eye-years. Several fixed and modifiable risk factors were identified, yielding a point system to guide cataract risk minimization. Topical corticosteroids only were associated with increased cataract risk when anterior chamber cells were absent or minimally present, suggesting their use to treat active inflammation (which itself is cataractogenic) does not cause a net increase in cataract incidence.

Corneal Endothelial Transplantation in Uveitis: Incidence and Risk Factors.

PURPOSE: To estimate the incidence of corneal endothelial transplantation (CET) and identify risk factors among patients with noninfectious ocular inflammation. DESIGN: Retrospective cohort study. METHODS: Adult patients attending United States tertiary uveitis care facilities diagnosed with noninfectious ocular inflammation were identified from the Systemic Immunosuppressive Therapy for Eye Diseases Cohort Study. Time-to-event analysis was used to estimate the incidence of CET, including penetrating keratoplasty, Descemet stripping endothelial keratoplasty, or Descemet membrane endothelial keratoplasty procedures. The incidence of CET was calculated. Potential risk factors for CET were also evaluated using Cox regression, accounting for correlation between eyes of the same patient. RESULTS: Overall, 14,264 eyes met eligibility criteria for this analysis, with a median follow-up of 1.8 eye-years. The Kaplan-Meier estimated incidence of CET within 10 years was 1.10% (95% CI, 0.68%-1.53%). Risk factors for CET included age >60 years vs <40 years (adjusted hazard ratio [aHR], 16.5; 95% CI, 4.70-57.9), anterior uveitis and scleritis vs other types (aHR, 2.97; 95% CI, 1.46-6.05; and aHR, 4.14; 95% CI,1.28-13.4, respectively), topical corticosteroid treatment (aHR, 2.84; 95% CI, 1.32-6.13), cataract surgery (aHR, 4.44; 95% CI, 1.73-11.4), tube shunt surgery (aHR, 11.9; 95% CI, 5.30-26.8), band keratopathy (aHR, 5.12; 95% CI, 2.34-11.2), and hypotony (aHR, 7.38; 95% CI, 3.14-17.4). Duration of uveitis, trabeculectomy, peripheral anterior synechia, and ocular hypertension had no significant association after multivariate adjustment. CONCLUSIONS: In patients with ocular inflammation, CET occurred infrequently. Tube shunt surgery, hypotony, band keratopathy, cataract surgery, and anterior segment inflammation were associated with increased risk of undergoing CET; these factors likely are associated with endothelial cell damage.

Risk of Cataract in Intermediate Uveitis.

PURPOSE: To determine the incidence of and predictive factors for cataract in intermediate uveitis. DESIGN: Retrospective cohort study. METHODS: Patients were identified from the Systemic Immunosuppressive Therapy for Eye Diseases Cohort Study, in which medical records were reviewed to determine demographic and clinical data of every eye/patient at every visit at 5 participating US tertiary care uveitis centers. The primary outcome was development of vision-compromising cataract as defined by a decrease in visual acuity to 20/40 or less, or requiring cataract surgery. Survival analysis assessed visually defined cataract to avoid bias due to timing of surgery vis-à-vis inflammatory status. RESULTS: Among 2,190 eyes of 1,302 patients with intermediate uveitis, the cumulative incidence of cataract formation was 7.6% by 1 year (95% confidence interval [CI] = 6.2%-9.1%), increasing to 36.6% by 10 years (95% CI = 31.2%-41.6%). Increased cataract risk was observed in eyes with concurrent anterior uveitis causing posterior synechiae (hazard ratio = 2.68, 95% CI = 2.00-3.59, P < .001), and in eyes with epiretinal membrane formation (hazard ratio = 1.54, 95% CI = 1.15-2.07, P = .004). Higher dose corticosteroid therapy was associated with significantly higher incidence of cataract, especially time-updated use of topical corticosteroids ≥2 times/d or ≥4 periocular corticosteroid injections. Low-dose corticosteroid medications (oral prednisone 7.5 mg daily or less, or topical corticosteroid drops <2 times/d) were not associated with increased cataract risk. CONCLUSIONS: Our study found that the incidence of clinically important cataract in intermediate uveitis is moderate. The risk is higher with markers of severity and with higher doses of corticosteroid medications, the latter being potentially modifiable.

Contemporaneous Risk Factors for Visual Acuity in Non-Infectious Uveitis.

INTRODUCTION: We evaluated the associations of clinical and demographic characteristics with visual acuity (VA) with over 5 years in a subspecialty noninfectious uveitis population. METHODS: Retrospective data from 5,530 noninfectious uveitis patients were abstracted by expert reviewers, and contemporaneous associations of VA with demographic and clinical factors were modeled. RESULTS: Patients were a median of 41 years old, 65% female, and 73% white. Eyes diagnosed ≥5 years prior to cohort entry had worse VA (-1.2 lines) than those diagnosed <6 months prior, and eyes with cataract surgery performed prior to entry had worse VA (-5.9 lines) than those performed during follow-up. Vitreous haze (-4.2 lines for 3+ vs quiet), hypotony (-2.5 lines for ≤5 mm Hg vs 6-23 mm Hg), and CNV (-1.8 lines) all were strongly associated with reduced VA. CONCLUSION: Factors associated with reduced VA included well-known structural complications, and lack of subspecialty care during cataract surgery.

Remission of Non-Infectious Anterior Scleritis: Incidence and Predictive Factors.

PURPOSE: To assess how often non-infectious anterior scleritis remits and identify predictive factors. METHODS: Our retrospective cohort study at four ocular inflammation subspecialty centers collected data for each affected eye/patient at every visit from center inception (1978, 1978, 1984, 2005) until 2010. Remission was defined as inactivity of disease off all suppressive medications at all visits spanning at least three consecutive months or at all visits up to the last visit (to avoid censoring patients stopping follow-up after remission). Factors potentially predictive of remission were assessed using Cox regression models. RESULTS: During 1,906 years' aggregate follow-up of 832 affected eyes, remission occurred in 214 (170 of 584 patients). Median time-to-remission of scleritis = 7.8 years (95% confidence interval [CI]: 5.7, 9.5). More remissions occurred earlier than later during follow-up. Factors predictive of less scleritis remission included scleritis bilaterality (adjusted hazard ratio [aHR] = 0.46, 95% CI: 0.32-0.65); and diagnosis with any systemic inflammatory disease (aHR = 0.36, 95% CI: 0.23-0.58), or specifically with Rheumatoid Arthritis (aHR = 0.22), or Granulomatosis with Polyangiitis (aHR = 0.08). Statin treatment (aHR = 1.53, 95% CI: 1.03-2.26) within ≤90 days was associated with more remission incidence. CONCLUSIONS: Our results suggest scleritis remission occurs more slowly in anterior scleritis than in newly diagnosed anterior uveitis or chronic anterior uveitis, suggesting that attempts at tapering suppressive medications is warranted after long intervals of suppression. Remission is less frequently achieved when systemic inflammatory diseases are present. Confirmatory studies of whether adjunctive statin treatment truly can enhance scleritis remission (as suggested here) are needed.

Visual Acuity Outcome over Time in Non-Infectious Uveitis.

Introduction: We evaluated visual acuity (VA) over 5 years in a subspecialty noninfectious uveitis population.Methods: Retrospective data from 5,530 noninfectious uveitis patients with anterior, intermediate, posterior or panuveitis were abstracted by expert reviewers. Mean VA was calculated using inverse probability of censoring weighting to account for losses to follow-up.Results: Patients were a median of 41 years old, 65% female, and 73% white. Initial mean VA was worse among panuveitis (20/84) than posterior (20/64), intermediate (20/47), and anterior (20/37) uveitides. On average, mean VA improved by 0.62, 0.51, 0.37, and 0.26 logMAR-equivalent lines over 2 years, respectively (each P < .001), then remained stable, except posterior uveitis mean VA worsened to initial levels.Conclusion: Mean VA of uveitic eyes improved and, typically, improvement was sustained under uveitis subspecialty care. Because VA tends to improve under tertiary care, mean VA change appears a better outcome for clinical studies than time-to-loss of VA.

Exudative Retinal Detachment in Ocular Inflammatory Diseases: Risk and Predictive Factors.

PURPOSE: This study evaluated the risk and risk factors for exudative retinal detachment (ERD) in ocular inflammatory diseases. DESIGN: Retrospective cohort study. METHODS: Patients with noninfectious ocular inflammation had been followed longitudinally between 1978 and 2007 at 4 US subspecialty uveitis centers. The main outcome measurements were occurrences of ERD and predictive factors. RESULTS: A total of 176 of 14,612 eyes with ocular inflammation presented with ERD. Among uveitis cases, Vogt-Koyanagi-Harada syndrome (VKH) (odds ratio [OR] = 109), undifferentiated choroiditis (OR = 9.18), sympathetic ophthalmia (OR = 8.43), primary or secondary panuveitis (OR = 7.09), multifocal choroiditis with panuveitis (OR = 4.51), and "other" forms of posterior uveitis (OR = 16.9) were associated with a higher prevalence of ERD. Among the 9,209 uveitic or scleritic eyes initially free of ERD and followed, 137 incident ERD cases were observed over 28,949 eye-years at risk (incidence rate = 0.47% [0.40%-0.56%/eye-year]). VKH (HR = 13.2), sympathetic ophthalmia (HR = 5.82), undifferentiated choroiditis (HR = 6.03), primary or secondary panuveitis (HR = 4.21), and rheumatoid arthritis (HR = 3.30) were significantly associated with incident ERD. A significant dose-response relationship with the prevalence and incidence of ERD were observed for AC cells and vitreous cell activity. African Americans had significantly higher prevalence and incidence of ERD. CONCLUSIONS: Other ocular inflammatory conditions in addition to VKH syndrome and posterior scleritis were associated with increased risk of ERD, indicating that ERD does not necessarily dictate a diagnosis of VKH or posterior scleritis. In addition, the relationship between ERD and inflammatory severity factors implies that inflammation is a key predictive factor associated with developing ERD and requires early and vigorous control.

Factors Predictive of Remission of Chronic Anterior Uveitis.

PURPOSE: To estimate the incidence of medication-free remission of chronic anterior uveitis and identify predictors thereof. DESIGN: Retrospective cohort study. PARTICIPANTS: Patients diagnosed with anterior uveitis of longer than 3 months' duration followed up at United States tertiary uveitis care facilities. METHODS: Estimation of remission incidence and identification of associated predictors used survival analysis. MAIN OUTCOME MEASURES: Incidence of medication-free remission. For the primary analysis, remission was defined as inactive uveitis while off treatment at all visits spanning an interval of at least 90 days or-for patients who did not return for follow-up after 90 days-remaining inactive without receiving suppressive medications at all of the last visits. Association of factors potentially predictive of medication-free remission was also studied. RESULTS: Two thousand seven hundred ninety-five eyes of 1634 patients with chronic anterior uveitis were followed up over 7936 eye-years (4676 person-years). The cumulative medication-free, person-year remission incidence within 5 years was 32.7% (95% confidence interval [CI], 30.4%-35.2%). Baseline clinical factors predictive of reduced remission incidence included longer duration of uveitis at presentation (for 2 to 5 years vs. less than 6 months: adjusted hazard ratio [aHR], 0.61; 95% CI, 0.44-0.83), bilateral uveitis (aHR, 0.75; 95% CI, 0.59-0.96), prior cataract surgery (aHR, 0.70; 95% CI 0.56-0.88), and glaucoma surgery (aHR, 0.63; 95% CI, 0.45-0.90). Two time-updated characteristics were also predictive of reduced remission incidence: keratic precipitates (aHR, 0.36; 95% CI, 0.21-0.60) and synechiae (aHR, 0.62; 95% CI, 0.41-0.93). Systemic diagnosis with juvenile idiopathic arthritis and spondyloarthropathy were also associated with reduced remission incidence. Older age at presentation was associated with higher incidence of remission (for age ≥40 years vs. <40 years: aHR, 1.29; 95% CI, 1.02-1.63). CONCLUSIONS: Approximately one third of patients with chronic anterior uveitis remit within 5 years. Longer duration of uveitis, younger age, bilateral uveitis, prior cataract surgery, glaucoma surgery, presence of keratic precipitates and synechiae, and systemic diagnoses of juvenile idiopathic arthritis and spondyloarthropathy predict reduced remission incidence; patients with these factors should be managed taking into account the higher probability of a longer disease course.

Comparison Between Methotrexate and Mycophenolate Mofetil Monotherapy for the Control of Noninfectious Ocular Inflammatory Diseases.

PURPOSE: To compare mycophenolate mofetil (MMF) to methotrexate (MTX) as corticosteroid-sparing therapy for ocular inflammatory diseases. DESIGN: Retrospective analysis of cohort study data. METHODS: Participants were identified from the Systemic Immunosuppressive Therapy for Eye Diseases Cohort Study. Demographic and clinical characteristics were obtained via medical record review. The study included 352 patients who were taking single-agent immunosuppression with MTX or MMF at 4 tertiary uveitis clinics. Marginal structural models (MSM)-derived statistical weighting created a virtual population with covariates and censoring patterns balanced across alternative treatments. With this methodological approach, the results estimate what would have happened had none of the patients stopped their treatment. Survival analysis with stabilized MSM-derived weights simulated a clinical trial comparing MMF vs MTX for noninfectious inflammatory eye disorders. The primary outcome was complete control of inflammation on prednisone ≤10 mg/day, sustained for ≥30 days. RESULTS: The time to success was shorter (more favorable) for MMF than MTX (hazard ratio = 0.68, 95% confidence interval: 0.46-0.99). Adjusting for covariates, the proportion achieving success was higher at every point in time for MMF than MTX from 2 to 8 months, then converges at 9 months. The onset of corticosteroid-sparing success took more than 3 months for most patients in both groups. Outcomes of treatment (MMF vs MTX) were similar across all anatomic sites of inflammation. The incidence of stopping therapy for toxicity was similar in both groups. CONCLUSIONS: Our results suggest that, on average, MMF may be faster than MTX in achieving corticosteroid-sparing success in ocular inflammatory diseases.

Risk of Ocular Hypertension in Adults with Noninfectious Uveitis.

PURPOSE: To describe the risk and risk factors for ocular hypertension (OHT) in adults with noninfectious uveitis. DESIGN: Retrospective, multicenter, cohort study. PARTICIPANTS: Patients aged ≥18 years with noninfectious uveitis seen between 1979 and 2007 at 5 tertiary uveitis clinics. METHODS: Demographic, ocular, and treatment data were extracted from medical records of uveitis cases. MAIN OUTCOME MEASURES: Prevalent and incident OHT with intraocular pressures (IOPs) of ≥21 mmHg, ≥30 mmHg, and increase of ≥10 mmHg from documented IOP recordings (or use of treatment for OHT). RESULTS: Among 5270 uveitic eyes of 3308 patients followed for OHT, the mean annual incidence rates for OHT ≥21 mmHg and OHT ≥30 mmHg are 14.4% (95% confidence interval [CI], 13.4-15.5) and 5.1% (95% CI, 4.7-5.6) per year, respectively. Statistically significant risk factors for incident OHT ≥30 mmHg included systemic hypertension (adjusted hazard ratio [aHR], 1.29); worse presenting visual acuity (≤20/200 vs. ≥20/40, aHR, 1.47); pars plana vitrectomy (aHR, 1.87); history of OHT in the other eye: IOP ≥21 mmHg (aHR, 2.68), ≥30 mmHg (aHR, 4.86) and prior/current use of IOP-lowering drops or surgery in the other eye (aHR, 4.17); anterior chamber cells: 1+ (aHR, 1.43) and ≥2+ (aHR, 1.59) vs. none; epiretinal membrane (aHR, 1.25); peripheral anterior synechiae (aHR, 1.81); current use of prednisone >7.5 mg/day (aHR, 1.86); periocular corticosteroids in the last 3 months (aHR, 2.23); current topical corticosteroid use [≥8×/day vs. none] (aHR, 2.58); and prior use of fluocinolone acetonide implants (aHR, 9.75). Bilateral uveitis (aHR, 0.69) and previous hypotony (aHR, 0.43) were associated with statistically significantly lower risk of OHT. CONCLUSIONS: Ocular hypertension is sufficiently common in eyes treated for uveitis that surveillance for OHT is essential at all visits for all cases. Patients with 1 or more of the several risk factors identified are at particularly high risk and must be carefully managed. Modifiable risk factors, such as use of corticosteroids, suggest opportunities to reduce OHT risk within the constraints of the overriding need to control the primary ocular inflammatory disease.

Aberrant regeneration of the third nerve (oculomotor synkinesis).

Aberrant regeneration of a third nerve palsy (oculomotor synkinesis) excludes an ischaemic cause and in the absence of relevant trauma strongly suggests a compressive aetiology. A scan is mandatory in such cases. We describe the case of a 52-year-old woman who presented with complete pupil-involving third nerve palsy from a posterior communicating artery aneurysm, who later developed widespread aberrant regeneration of pupil, eyelid and third nerve territory rectus muscles.