The impact of a multidisciplinary intervention to reduce severe retinopathy of prematurity in Kampala, Uganda.

BACKGROUND: To address the threat of retinopathy of prematurity (ROP) in Sub-Saharan Africa (SSA), the Stop Infant Blindness in Africa (SIBA) project introduced a comprehensive program, including subspecialty training and oxygen management equipment. METHODS: A before-and-after retrospective cohort study compared preterm infants < 1750 g or < 34 weeks' gestation before (2022) and after (2023) program implementation. Outcomes included: the proportion with severe ROP, the proportion with Zone III vascularization on first examination, and factors associated with severe ROP. RESULTS: Overall, 140 infants were screened before and 122 after program implementation. The proportion with Zone III vascularization increased from 16.1% (N = 11) pre-intervention to 44.9% (N = 32) post-intervention (p = 0.001). The proportion with severe ROP decreased from 27.8% (N = 19) to 12.8% (N = 9, p = 0.03). Factors predicting severe ROP on adjusted analyses were gestational age and blood transfusion. CONCLUSION: In SSA, introduction of a comprehensive program to prevent and treat ROP can decrease the risk of severe ROP.

Retinopathy of Prematurity in the 21st Century and the Complex Impact of Supplemental Oxygen.

Retinopathy of prematurity (ROP) is a leading cause of childhood blindness. Not only do the epidemiologic determinants and distributions of patients with ROP vary worldwide, but clinical differences have also been described. The Third Edition of the International Classification of ROP (ICROP3) acknowledges that aggressive ROP (AROP) can occur in larger preterm infants and involve areas of the more anterior retina, particularly in low-resource settings with unmonitored oxygen supplementation. As sub-specialty training programs are underway to address an epidemic of ROP in sub-Saharan Africa, recognizing characteristic retinal pathology in preterm infants exposed to unmonitored supplemental oxygen is important to proper diagnosis and treatment. This paper describes specific features associated with various ROP presentations: oxygen-induced retinopathy in animal models, traditional ROP seen in high-income countries with modern oxygen management, and ROP related to excessive oxygen supplementation in low- and middle-income countries: oxygen-associated ROP (OA-ROP).

Blindness Secondary to Retinopathy of Prematurity in Sub-Saharan Africa.

PURPOSE: Retinopathy of Prematurity (ROP) has been suggested to be increasing in Africa. However, it was only previously documented as a cause of blindness in 8 of 48 (16.7%) sub-Saharan African countries. The purpose of this study was to better understand the magnitude and breadth of blindness from ROP in sub-Saharan Africa. METHODS: A questionnaire was sent to 455 ophthalmologists practicing in sub-Saharan Africa; the questionnaire was available in English, French and Portuguese. RESULTS: Responses were received from 132 of 455 (29%) ophthalmologists to whom the survey was sent. Eighty-three respondents were identified as ROP-involved ophthalmologists and were from 26 of 48 (54%) sub-Saharan African countries. Ophthalmologists in 23 countries reported that they examined at least one child who was blind from ROP during the last 5 years. Sixteen of these countries had not previously reported cases of blindness from ROP in the literature. The perceived occurrence of Type 1 or more severe ROP was reported to be increasing by 31 of 77 (40%) ROP-involved ophthalmologists. ROP-involved pediatric ophthalmologists and retinal surgeons reported the number of infants they examined annually with Type 1 or more severe ROP increased from a median of 1 (range: 0-15) to a median of 4 (range: 0-40) from 2015 to 2019. ROP was estimated to be the cause of blindness for 10% of all blind children examined by ROP-involved pediatric ophthalmologists and retinal surgeons during 2019. CONCLUSIONS: ROP is becoming a more important and widespread cause of childhood blindness in sub-Saharan Africa.

Oxygen management among infants in neonatal units in sub-Saharan Africa: a cross-sectional survey.

OBJECTIVES: To provide more comprehensive data on the management of oxygen supplementation in neonates in sub-Saharan Africa. STUDY DESIGN: An online survey on the management of oxygen supplementation for infants in neonatal units was sent to 278 healthcare personnel in sub-Saharan Africa. RESULTS: One hundred and nine responses from 82 neonatal care units in 54% (26/48) sub-Saharan African countries were received. All units had the capacity to provide oxygen supplementation. However, only 50% (38/76) had access to blend oxygen with medical air and 1% (1/75) had the capacity to blend oxygen/air for every infant. Although 96% (72/75) of units could monitor oxygen saturation, monitoring was mostly intermittent and only 32% (24/75) were able to monitor oxygen saturation in every infant receiving oxygen supplementation. CONCLUSIONS: Findings indicate that oxygen supplementation is inadequately managed in neonatal units in sub-Saharan Africa, which may put infants at risk of developing severe ROP.

Does general anesthesia or intravitreal injection affect neurodevelopment in children undergoing ophthalmic procedures?

PURPOSE OF REVIEW: To review recent studies on potential neurodevelopmental impacts on the pediatric population through general anesthesia events or intravitreal anti-vascular endothelial growth factor (VEGF) injection. RECENT FINDINGS: Studies on this topic have been extensive with varied reported neurodevelopmental outcomes. Initial investigations in rodents and primates showed negative impact of anesthetics on neurodevelopment. Subsequent retrospective human reviews had mixed results whereas more recent sibling and prospective studies have been published without evidence of clinically significant impact. A similar narrative has more recently come to play regarding the long-term effects of intravitreal injections used in neonates with retinopathy of prematurity. Publications initially indicated a negative correlation whereas later reviews have found no difference between those receiving injections versus laser treatment. SUMMARY: Given that recent data on both general anesthesia events and intravitreal anti-VEGF injections do not show a long-term negative neurodevelopmental impact, ocular procedures needed to improve a pediatric patient's vision or quality of life should not be delayed.

Necrotizing Tenon's capsule infection in a lymphopenic Down syndrome patient following strabismus surgery.

Periocular infection is a rare complication of strabismus surgery. We describe a case of necrotizing Tenon's capsule infection after uncomplicated strabismus surgery in a boy with Down syndrome and blepharitis. Pathologic diagnosis was severe acute necrotizing inflammation with Gram positive coccal forms. Resolution of infection occurred after surgical debridement and intravenous and topical antibiotics. Work-up revealed lymphopenia related to Down syndrome. Patients with Down syndrome may have risk factors for postoperative infection including blepharitis and immunologic abnormalities.

Decreased Binocular Summation in Strabismic Amblyopes and Effect of Strabismus Surgery.

PURPOSE: Binocular summation (BiS) occurs when binocular visual function surpasses that of the better eye alone. We sought to evaluate whether strabismic amblyopia reduces BiS more than strabismus alone, and determine whether BiS improves in strabismic amblyopes after strabismus surgery. METHODS: We prospectively recruited 15 patients with strabismic amblyopia who then underwent strabismus surgery. Thirty age-matched normal subjects and 30 non-amblyopic strabismic patients served as controls. Subjects underwent binocular and monocular visual acuity testing on high-contrast Early Treatment Diabetic Retinopathy Study (ETDRS) as well as 2.5% and 1.25% Sloan low contrast acuity (LCA) charts. BiS was calculated as the difference between better eye and binocular scores. RESULTS: Strabismic amblyopes and strabismic controls did not significantly differ in preoperative BiS, but both had subnormal BiS preoperatively on LCA charts. Among 11 strabismic amblyopes with preoperative and postoperative BiS measurements, average postoperative BiS was not significantly different from preoperative. Improved LCA BiS postoperatively occurred in some patients and was associated with measurable preoperative stereoacuity (P=0.02), older age at strabismus onset (P=0.02), and larger preoperative angle of strabismus (P=0.0043). CONCLUSIONS: In this preliminary study, strabismic amblyopes experienced subnormal BiS, but amblyopia generally did not further impair BiS beyond that due to strabismus alone. Some strabismic amblyopes experienced improved low-contrast BiS after strabismus surgery. This suggests that further investigation in larger groups of patients should be undertaken to analyze a previously unrecognized functional benefit of strabismus surgery in strabismic amblyopes.

Binocular Summation and Control of Intermittent Exotropia.

BACKGROUND: Binocular summation (BiS), or improvement in binocular vision exceeding the better eye alone, is affected by strabismus. Being easily measured, BiS may be a useful indicator for subjective outcomes like stereopsis in strabismus. This study aims to investigate the relationship between BiS and measures of control of intermittent exotropia (IXT). METHODS: Patients with IXT were recruited before undergoing strabismus surgery and underwent tests of binocular and monocular high- and low-contrast visual acuity, stereopsis at distance and near, and Newcastle Control Score (NCS), a score developed by incorporating home control and clinic control criteria into a control rating scale. BiS was calculated using high-contrast Early Treatment of Diabetic Retinopathy Study (ETDRS) and Sloan low-contrast acuity charts (LCA) at 2.5% and 1.25% contrast as the difference between the binocular score and that of the better eye. The relationship between BiS and measures of IXT control (NCS and distance near stereoacuity disparity) was evaluated using a correlation analysis by Spearman correlation coefficients and the Kruskal-Wallis test. RESULTS: Thirty-four patients were included (mean [± standard deviation (SD)] age 19±16 years) having a mean (±SD) of 26±16Δ IXT at distance and 20±16Δ at near. Mean (±SD) BiS for ETDRS and Sloan LCA at 2.5% and 1.25% was 0.8±3.6, 1.9±6.0, and -2.3±7.2, respectively. The Spearman correlation coefficient of BiS and NCS was -0.53 (95% CI -0.85 to -0.25) for 2.5% LCA and -0.43 (95% CI -0.77 to -0.13) for 1.25% LCA. BiS at 2.5% LCA (P=0.006) and at 1.25% LCA (P=0.029) significantly differed between the groups based on NCS score groupings (1-3, 4-6, and 7-9), with patients who had better control scores having higher levels of BiS. BiS did not differ significantly between patients grouped according to the difference between stereoacuity measured at near versus distance. CONCLUSION: Significantly lower low-contrast BiS in patients with higher NCS may suggest that decreased BiS is associated with less control in IXT. This finding suggests that BiS may reflect control in IXT across a population of patients with IXT.

Prospective, Randomized Clinical Trial of Povidone-Iodine 1.25% Solution Versus Topical Antibiotics for Treatment of Bacterial Keratitis.

PURPOSE: To compare povidone-iodine 1.25% ophthalmic solution with topical antibiotics for treatment of bacterial keratitis in areas of the world where use of effective topical antibiotics may not be an option. STUDY DESIGN: Randomized, controlled, investigator-masked clinical trial. METHODS: We randomized 172 individuals with bacterial keratitis to topical treatment with povidone-iodine or antibiotics (neomycin-polymyxin B-gramicidin in the Philippines; ciprofloxacin 0.3% in India). Using survival analysis, we compared intervals from start of treatment to "presumed cure" (primary outcome measure, defined as a closed epithelial defect without associated inflammatory signs) and to "recovering" (residual epithelial defect <1 mm2 with only minimal inflammation). RESULTS: Median interval to presumed cure in the Philippines was 7 days for povidone-iodine and 7 days for neomycin-polymyxin B-gramicidin (95% confidence interval [CI] for difference in median interval, -9.5 to 0.7 days) and in India was 12 days for povidone-iodine and 17 days for ciprofloxacin (95% CI, -35.2 to 3.2 days). Hazard ratio (HR) for presumed cure among those treated with povidone-iodine (vs antibiotics) was 1.46 in the Philippines (95% CI, 0.90-2.36; P = .13) and 1.70 in India (95% CI, 0.73-3.94; P = .22). Comparisons of intervals to recovering and HR for recovering also revealed no significant differences between treatment groups in either country. CONCLUSIONS: There is no significant difference between the effect of topical povidone-iodine 1.25% and topical antibiotics commonly available in the developing world for treatment of bacterial keratitis. Povidone-iodine 1.25%, which is widely available and inexpensive, can be considered for treatment of bacterial keratitis when antibiotic treatment is not practical.

Improvement in binocular summation after strabismus surgery.

IMPORTANCE: Binocular summation (BiS), or improvement in visual acuity using binocular vision compared with the better eye alone, is diminished in patients with strabismus. However, it is still not known how strabismus surgery affects BiS. OBJECTIVE: To determine whether BiS improves after strabismus surgery. DESIGN, SETTING, AND PARTICIPANTS: Prospective study of 97 patients undergoing strabismus surgery between September 1, 2011, and January 31, 2014, comparing preoperative and postoperative measures of BiS. Patients were recruited within 1 month before undergoing strabismus surgery. The study took place at an academic pediatric ophthalmology and strabismus practice. INTERVENTION: Strabismus surgery. MAIN OUTCOMES AND MEASURES: All patients underwent high- and low-contrast visual acuity testing binocularly and monocularly at preoperative and 2-month postoperative visits. Binocular summation was calculated for high-contrast Early Treatment of Diabetic Retinopathy Study charts and Sloan low-contrast acuity charts at 2.5% and 1.25% contrast as the difference between the binocular score and that of the better eye. Preoperative and postoperative values were compared. RESULTS: There was an improvement in BiS at the 2 low-contrast levels for all patients and for all contrast levels in the 75 patients in whom surgery successfully restored binocular alignment. For low-contrast acuity, the proportion of patients with a BiS score of at least 5 letters postoperatively was almost twice that of preoperatively (21% to 30% and 13% to 26% for 2.5% contrast and 1.25% contrast, respectively). Similarly, the proportion of patients with binocular inhibition (BiS score worse by at least 5 letters than the better eye score) was decreased postoperatively at all contrast levels (from 22% to 14% for 1.25% contrast). Thirty-one percent of patients experienced improvement in BiS scores postoperatively at the lowest contrast level. CONCLUSIONS AND RELEVANCE: Binocular summation scores improved postoperatively in most patients undergoing strabismus surgery. This occurred most frequently at the lowest contrast level. These findings suggest that improved BiS could represent a newly recognized functional benefit from the surgical correction of strabismus. Further studies evaluating the correlation of BiS with stereopsis, visual field expansion, and quality of life will be necessary to fully evaluate the role that improved BiS has in improving binocularity postoperatively.

Quality of life in adults with strabismus.

PURPOSE: To assess relative quality of life in patients with strabismus. DESIGN: Retrospective cohort study. METHODS: The 25-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) was performed in 42 strabismic adults over the age of 50 years at a single institution. Subscale scores were compared with those of patients with other ocular diseases, including diabetic retinopathy, age-related macular degeneration (AMD), glaucoma, cataract, cytomegalovirus (CMV) retinitis, and low vision. RESULTS: Median visual acuity was 20/20 (range 20/12.5-20/50), and 34 patients (81%) reported diplopia. Strabismic patients performed the same or worse on nearly all vision-related subscales than did patients with diabetic retinopathy, age-related macular degeneration, glaucoma, cataract, and CMV retinitis. Additionally, strabismic patients reported significantly worse ocular pain than all comparison groups before any surgery was performed. CONCLUSIONS: Strabismus impacts quality of life through both functional and psychosocial factors. Physicians treating strabismic patients should recognize these quality-of-life issues and address them accordingly.

X-linked Megalocornea Associated with the Novel CHRDL1 Gene Mutation p.(Pro56Leu*8).

BACKGROUND: The genetic basis of X-linked megalocornea (MGC1) was reported in 2012 to be caused by mutations in the CHRDL1 gene. We sought to confirm that mutations in CHRDL1 are associated with MGC1 in a previously unreported pedigree. MATERIALS AND METHODS: Slit lamp examination, corneal pachymetry, corneal topography and DNA collection for screening of the CHRDL1 gene were performed for members of an affected family. RESULTS: Examination of a woman and her four sons, ranging in age between 3 and 15 years, demonstrated horizontal corneal diameters of 14 mm in three of the four sons and a normal corneal diameter of 12 mm in the mother and other son. Central corneal thickness in the individuals with enlarged corneal diameters averaged 474 microns, compared to 604 microns in their unaffected brother. Corneal topographic imaging demonstrated an average K value of 44.4 D in the affected individuals compared with 41.6 D in their unaffected sibling. Screening of the CHRDL1 gene demonstrated the novel hemizygous frameshift mutation c.167delC (p.(Pro56Leu*8)) in exon 3 in the affected individuals and in the heterozygous state in their mother. This mutation was not present in the unaffected brother or in unrelated controls. CONCLUSION: We provide the initial confirmation that X-linked megalocornea is associated with mutations in the CHRDL1 gene.

Binocular inhibition in strabismic patients is associated with diminished quality of life.

PURPOSE: To characterize the relationship between binocular summation (BiS) and binocular inhibition (BI) on the quality of life of adults and children with strabismus. METHODS: Strabismus patients at a single center from 2010 to 2012 were prospectively enrolled. A BiS score was measured using ETDRS and Sloan low-contrast visual acuity (LCA) protocols at 2.5% and 1.25% contrast. Patients were categorized as having BiS (binocular better than better-eye visual acuity by ≥5 letters), BI (binocular worse than better-eye visual acuity by ≥5 letters), or otherwise indeterminate visual acuity (a difference between binocular visual acuity and monocular visual acuity of the better eye of <5 letters). Quality of life was evaluated by the National Eye Institute Visual Functioning Questionnaire 25 (VFQ-25), 20-item Adult Strabismus Questionnaire (AS-20), and the Amblyopia and Strabismus Questionnaire. RESULTS: A total of 108 patients were included. There was no significant BiS or BI for high-contrast ETDRS or 2.5% LCA tests; however, a mean BiS score of -2.14 ± 7.0 letters for 1.25% LCA demonstrated significant binocular inhibition (P = 0.004) for this contrast level. The mean composite VFQ-25 score was significantly lower in subjects with BI on ETDRS (80 ± 19 vs 57 ± 7 for subjects with BiS and BI, resp. [P = 0.03]), 2.5% LCA (81 ± 14 vs 66 ± 16 for subjects with BiS and BI, resp. [P = 0.01]), and 1.25% LCA tests (91 ± 9 vs 72 ± 14 for subjects with BiS and BI, resp. [P = 0.005]). After accounting for potential covariates, significant association persisted for BI, demonstrated by 1.25% LCA (P = 0.01). With BI demonstrable at 2.5%, AS-20 scores were also significantly lower (P = 0.04). CONCLUSIONS: Strabismic patients with BI had significantly lower quality-of -life scores than those who did not, even after accounting for potential covariates and the absence of diplopia.

Assessment of torsion after superior rectus transposition with or without medial rectus recession for Duane syndrome and abducens nerve palsy.

BACKGROUND: Superior rectus transposition with or without medial rectus recession has been advocated for the treatment of abducens nerve palsy and esotropic Duane syndrome. Early reports have focused mainly on postoperative ocular alignment, but there is concern that superior rectus transposition may induce torsional misalignment. The purpose of this study was to evaluate torsional outcomes after superior rectus transposition surgery using prospective preoperative and postoperative torsional assessments. METHODS: Prospective measurements were performed on all patients undergoing superior rectus transposition. Preverbal infants were assessed using fundus torsion evaluating the position of the fovea relative to the optic nerve; older children/adults underwent double Maddox rod (DMR) assessment of torsion. RESULTS: A total of 11 subjects met the study inclusion criteria. The etiology of strabismus was an abducens nerve palsy (n = 7) or Duane syndrome (n = 4). For the subjects evaluated by fundus torsion (n = 4), there was no significant change in torsion for 3 (75%). For those subjects undergoing DMR (n = 7), there was a significant change in subjective torsion (4.7 ± 3.8°excyclotorsion vs 0.0° ± 5.0° excyclotorsion; P = 0.004). Esotropic deviation improved significantly for all subjects (39(Δ) ± 23(Δ) vs 6.5(Δ) ± 13(Δ); P = 0.001) and no significant mean vertical deviation postoperatively, although 1 patient had a clinically significant postoperative hypertropia measuring 14(Δ). Abduction also improved significantly (-4.2 ± 0.9 vs -2.8 ± 1, P = 0.0001). CONCLUSIONS: In this patient series, superior rectus transposition with medial rectus recession did not have clinically significant induction of torsional diplopia as a result of the procedure.

The effectiveness of an autorefractor with eye-tracking capability in pediatric patients.

PURPOSE: To study the diagnostic accuracy and effectiveness in children of a new autorefractor with eye-tracking capability. METHODS: Children aged 3-17 years were tested with a Marco Nidek ARK-560A autorefractor before and after cycloplegia. Cycloplegic manifest refractions were conducted on the more cooperative children. Measurements were converted to vector representations M (sphere), J0, and J45 (cylinder) by Fourier analysis and compared before and after cycloplegia for autorefractor measurements and clinical manifest and retinoscopic determinations. RESULTS: A total of 88 subjects were included. Autorefractor measurements were successfully obtained on all subjects. Before cycloplegia the mean spherical portion of the refractive error by autorefractor measurement (AR Dry) averaged 0.29 ± 0.75 D less hyperopia than the clinical manifest refraction (P < 0.005). After cycloplegia, mean autorefractor measurements (AR Wet) demonstrated 1.03 ± 0.84 D more hyperopia in the spherical component than AR Dry (P < 0.001). The spherical component of autorefraction and clinical measurements after cycloplegia were not statistically different, but the J0 astigmatic findings differed by 0.13 D ± 0.25 (P < 0.0003). For the 27 children under 8 years of age, precycloplegic autorefractor findings differed from manual cycloplegic retinoscopy by 1.48 D ± 1.13 for sphere (P < 0.001) but were not statistically different for astigmatic parameters. CONCLUSIONS: Autorefractors can estimate manual retinoscopy values in children and may prove useful in the office setting in evaluating pediatric patients. Autotracking allowed successful acquisition of measurements in all subjects.

Effect of strabismus surgery on torticollis caused by congenital superior oblique palsy in young children.

PURPOSE: To evaluate the outcome of strabismus surgery for congenital superior oblique palsy (SOP) in relation to correction of head tilt and hypertropia. The cohort of patients mainly involved very young children. This is the first study to use a standardized instrument to objectively measure torticollis before and after surgery. MATERIALS AND METHODS: A non-comparative interventional case series of 13 cases of congenital superior oblique palsy with head tilt, who underwent simultaneous superior oblique tuck and inferior oblique recession between Jan 2000 and Dec 2008, were studied. RESULTS: The mean duration of SOP until surgery was 36.8 months. Of the 12 unilateral cases, 8 were right-sided. Mean follow-up period was 17 months (range 7-36). The outcome was determined at the last follow-up. Mean pre-and post-operative hypertropia (p.d.) in forced primary position was 19 ± 7 and 2 ± 6, respectively ( P < 0.0001). The head tilt reduced from mean of 17 ± 9 to 2 ± 2 degrees ( P < 0.0001). Success, defined as hypertropia <5 PD and head tilt less than 5 degrees, was achieved in 69% (9/13. C.I. 42-88%) and 85% (11/13. C.I. 56-96%), respectively. The success rate for achieving both criteria was 61.5% (C.I. 35-88%). Five patients required additional surgery; usually a contralateral inferior rectus muscle recession, which was successful in all cases. One case developed asymptomatic Brown syndrome (7.69% - C.I. 6.7-22.2). CONCLUSIONS: Simultaneous superior oblique tuck and inferior oblique muscle recession can successfully treat selected cases of congenital superior oblique palsy. About one-third required an additional procedure, which led to total normalization of the head position.

Functional burden of strabismus: decreased binocular summation and binocular inhibition.

IMPORTANCE: Binocular summation (BiS) is defined as the superiority of visual function for binocular over monocular viewing. Binocular summation decreases with age and large interocular differences in visual acuity. To our knowledge, BiS has not heretofore been well studied as a functional measure of binocularity in strabismus. OBJECTIVE: To evaluate the effect of strabismus on BiS using a battery of psychophysical tasks that are clinically relevant and easy to use and to determine whether strabismus is associated with binocular inhibition in extreme cases. DESIGN: Case-control study. SETTING: University-based eye institute. PARTICIPANTS: Strabismic patients recruited during 2010 to 2012 from a preoperative clinic and control participants with no history of eye disease other than refractive error. INTERVENTION: A battery of psychophysical and electrophysiological tests including Early Treatment Diabetic Retinopathy Study visual acuity, Sloan low-contrast acuity (LCA) (2.5% and 1.25%), Pelli-Robson contrast sensitivity, and sweep visual evoked potential contrast sensitivity. MAIN OUTCOME AND MEASURE: Binocular summation was calculated as the ratio between binocular and better-eye individual scores. RESULTS: Sixty strabismic and 80 control participants were prospectively examined (age range, 8-60 years). Mean BiS was significantly lower in the strabismic patients than controls for LCA (2.5% and 1.25%, P = .005 and <.001, respectively). For 1.25% LCA, strabismic patients had a mean BiS score less than 1, indicating binocular inhibition (ie, the binocular score was less than that of the better eye's monocular score). There was no significant difference in BiS for contrast thresholds on Early Treatment Diabetic Retinopathy Study visual acuity, Pelli-Robson contrast sensitivity, or sweep visual evoked potential contrast sensitivity. Regression analysis revealed a significant worsening of BiS with strabismus for 2.5% (P = .009) and 1.25% (P = .002) LCA, after accounting for age. CONCLUSIONS AND RELEVANCE: Strabismic patients demonstrate subnormal BiS and even binocular inhibition for LCA, suggesting that strabismus impairs visual function more than previously appreciated. This may explain why strabismic patients who are not diplopic close 1 eye in visually demanding situations. This finding clarifies the visual deficits impacting quality of life in strabismic patients and may represent a novel measure by which to evaluate and monitor function in strabismus.

Monitoring the conjunctiva for carbon dioxide and oxygen tensions and pH during cardiopulmonary bypass.

The purpose of this study was to measure, for the first time, multiple physiologic parameters of perfusion (pH, PCO2, PO2, and temperature) from the conjunctiva of adult patients during cardiopulmonary bypass while undergoing cardiothoracic surgery. Ten patients who underwent either intracardiac valve repair, atrial septal defect repair, or coronary artery bypass graft surgery had placement of a sensor which directly measured pH, PCO2, PO2, and temperature from the conjunctiva. Data were stratified into seven phases (0-5 minutes prior to bypass; 0-5, 6-10, and 11-15 minutes after initiation of bypass; 0-5 minutes prior to conclusion of bypass; and 0-5 and 6-10 minutes after bypass) and analyzed using a mixed model analysis.The change in conjunctival pH over the course of measurement was not statistically significant (p = .56). The PCO2 level followed a quadratic pattern, decreasing from a mean pre-bypass level of 37.7 mmHg at baseline prior to the initiation of cardiopulmonary bypass to a nadir of 33.2 mmHg, then increasing to a high of 39.4 mmHg at 6-10 minutes post bypass (p < .01). The PO2 declined from a mean pre-bypass level of 79.5 mmHg to 31.3 mmHg by 6-10 minutes post bypass and even post-bypass, it never returned to baseline values (p < .01). Temperature followed a pattern similar to PCO2 by returning to baseline levels as the patient was re-warmed following bypass (p < .01). There was no evidence of any eye injury or inflammation following the removal of the sensor. In the subjects studied, the conjunctival sensor yielded reproducible measurements during the various phases of cardiopulmonary bypass without ocular injury. Further study is necessary to determine the role of conjunctival measurements in critical settings.

Horizontal mattress technique for superior oblique suture spacer.

Superior oblique tendon overaction and Brown syndrome have been managed surgically by means of tenotomy/tenectomy, use of a silicon expander, and elongation with autologous fascia lata. These solutions are problematic with respect to corrective precision, injury and complications, or surgical difficulty. We present a simple "mattress" suture spacer technique that allows a precise and secure intraoperative adjustment.