Biomedical subjects

David K Coats

Publications and source records attributed to David K Coats.

At least 19 recordsLinked to original sources

PubMed2006

Visual outcomes after 3-port lens-sparing vitrectomy in stage 4 retinopathy of prematurity.

OBJECTIVE: To assess the visual acuity of eyes successfully treated with 3-port lens-sparing vitrectomy for stage 4 retinopathy of prematurity. METHODS: Of 102 consecutive eyes achieving at least posterior pole reattachment, 30 eyes of 26 patients were tested by Teller or Allen acuity measurements and were subsequently converted to logarithm of the minimum angle of resolution (logMAR). Visual outcomes were also examined as either favorable or unfavorable (Snellen equivalent >20/200). RESULTS: Seventy-two eyes were not tested because of either inability to perform testing (age or neurologic sequelae related to prematurity) or loss of follow-up. Of those tested, mean +/- SD logMAR visual acuity for the stage 4A and stage 4B groups was 0.51 +/- 0.09 (Snellen approximate 20/62) and 1.03 +/- 0.19 (Snellen approximate 20/200), respectively (odds ratio, 0.39; 95% confidence interval, 0.24-0.64; P = .001). Of those eyes assessed by Teller measurements, 10 of 10 stage 4A eyes and 3 (37.5%) of 8 stage 4B eyes had favorable outcomes; among eyes assessed with Allen measurements, 4 of 4 stage 4A eyes and 0 of 8 stage 4B eyes had favorable outcomes. CONCLUSIONS: The majority of eyes were not tested. Among eyes tested after successful 3-port lens-sparing vitrectomy, some eyes treated prior to macular detachment may be associated with a more favorable outcome and improved maintenance of functional visual acuity.

Female↗

PubMed2006

Prevalence and course of strabismus in the first year of life for infants with prethreshold retinopathy of prematurity: findings from the Early Treatment for Retinopathy of Prematurity study.

OBJECTIVE: To present strabismus data for premature infants with prethreshold retinopathy of prematurity (ROP) enrolled in the Early Treatment for Retinopathy of Prematurity study. DESIGN: The prevalence of strabismus was tabulated for all of the infants with high-risk prethreshold disease who participated in the randomized trial of the Early Treatment for Retinopathy of Prematurity study and were examined at 6 and/or 9 months' corrected age as well as for all of the infants with low-risk prethreshold disease who were examined at 6 months' corrected age. MAIN OUTCOME MEASURES: Presence or absence of strabismus at 6 and 9 months' corrected age. RESULTS: The prevalence of strabismus at 6 months was higher for infants with high-risk prethreshold ROP than for those with low-risk prethreshold ROP (20.3% vs 9.6%, respectively; P<.001). Risk factors associated with the development of strabismus at 9 months include abnormal fixation behavior, presence of amblyopia, and outborn birth status (ie, born outside of a study-affiliated hospital). At 9 months, 30% of infants with high-risk prethreshold ROP had strabismus, although only 42% showed strabismus at 6 months. Thirty percent of infants with strabismus at 6 months showed normal alignment at 9 months. CONCLUSIONS: Infants with high-risk prethreshold ROP show significant variability in the presence vs absence of strabismus in the first year of life; thus, conservative management is recommended. APPLICATION TO CLINICAL PRACTICE: Ophthalmologists managing strabismus in infants who have high-risk prethreshold ROP should be aware of the significant variability in ocular alignment during the first year of life.

Female↗

PubMed2005

Long-term outcomes of photorefractive keratectomy for anisometropic amblyopia in children.

PURPOSE: To evaluate the long-term visual acuity (VA) and refractive error responses to excimer laser photorefractive keratectomy (PRK) for treatment of anisometropic amblyopia in children. DESIGN: Prospective interventional case-control study. PARTICIPANTS: Eleven children, 2 to 11 years old, with anisometropic amblyopia who were noncompliant with conventional therapy with glasses or contact lenses and occlusion therapy were treated with PRK. A cohort derived retrospectively of 13 compliant and 10 noncompliant children with refractive errors similar to those of the PRK group who were treated with traditional anisometropic amblyopia therapy served as control groups. INTERVENTION: Photorefractive keratectomy for the eye with the higher refractive error. MAIN OUTCOME MEASURES: (1) Refractive error reduction and stability in the treated eye, (2) cycloplegic refraction, (3) VA, (4) stereoacuity, and (5) corneal haze up to 3 years after PRK. Compliant and noncompliant children with anisometropia amblyopia were analyzed as controls for refractive error and VA. RESULTS: Preoperative refractive errors were -13.70 diopters (D) (+/-3.77) for the myopic group and +4.75 D (+/-0.50) for the hyperopic group. Mean postoperative refractive errors at last follow-up (mean, 31 months) were -3.55 D (+/-2.2.5) and +1.41 D (+/-1.07) for the myopic and hyperopic groups, respectively. At last follow-up, cycloplegic refractions in 4 (50%) of 8 myopes and all hyperopes (100%) were within 3 D of that of the fellow eye. Five (63%) of 8 myopic children achieved a refraction within 2 D of the target refraction. Two (67%) of 3 hyperopic patients maintained their refractions within 2 D of the target. Refractive regressions (from 1 year after surgery to last follow-up) were 0.50+/-1.41 D (myopes) and 0.60+/-0.57 D (hyperopes). Seven children (77%) were able to perform psychophysical VA testing preoperatively and postoperatively. Five (71%) of the 7 children had uncorrected VA improvement of at least 2 lines, and 4 (57%) of 7 had best spectacle-corrected VA improvement of at least 2 lines, with 1 improving 7 lines. Five (55%) of 9 children had improvement of their stereoacuity at last follow-up. Subepithelial corneal haze remained negligible. The mean final VA of the PRK group was significantly better than that of the noncompliant control group (P = 0.003). The mean final refractive error for both myopic and hyperopic groups was also significantly better that that of the control groups (P = 0.007 and P<0.0001, respectively). CONCLUSIONS: Photorefractive keratectomy for severe anisometropic amblyopia in children resulted in long-term stable reduction in refractive error and improvement in VA and stereopsis, with negligible persistent corneal haze.

Amblyopia↗

PubMed2005

Reasons for delay of surgical intervention in adult strabismus.

BACKGROUND: It has been our impression that adult patients with strabismus frequently delay surgical intervention. OBJECTIVES: To determine the length of time adult patients waited before undergoing strabismus surgery and to determine the reasons why these delays occurred. DESIGN, SETTING, AND PARTICIPANTS: Prospective survey of consecutive patients who delayed strabismus surgery for more than 1 year. INTERVENTION: Preoperative survey. MAIN OUTCOME MEASURES: The primary outcome measure was time between the onset of strabismus and surgery and the reason why surgery had not been previously sought. RESULTS: The mean age among 128 study participants was 45.7 years (age range, 18-86 years). The mean time between the onset of current strabismus and surgery was 19.9 years (range, 1-72 years). The major reasons for delay in seeking surgical treatment included the following: surgery was never offered by eye care specialist (35 patients [27%]), surgery was offered but declined by the patient (29 patients [23%]), the patient had received prior satisfactory nonsurgical care (17 patients [13%]), the patient had never sought care (14 patients [11%]), the patient had a previous poor surgical experience (8 patients [6%]), and the patient had been told by their eye specialist that nothing could be done or that surgery could make them worse (8 patients [6%]). CONCLUSIONS: Strabismus surgery is often delayed for many years in adult patients who could potentially benefit from it. Almost half of such delays could be avoided by better education of the lay public and the medical community.

Adolescent↗

PubMed2005

Involution of retinopathy of prematurity after laser treatment: factors associated with development of retinal detachment.

PURPOSE: To identify specific features during the process of involution of retinopathy of prematurity after treatment at threshold that are associated with development of a retinal detachment. DESIGN: Retrospective case series. METHODS: The evolution of retinal detachments over time was analyzed retrospectively in 262 treated eyes of 138 infants. Specific features hypothesized to be associated with development of a retinal detachment were analyzed, including vitreous organization defined as clinically important, active stage 3 disease and active plus disease more than 21 days after treatment, and vitreous hemorrhage defined as clinically important. RESULTS: A retinal detachment developed in 36 (13.7%) of 262 eyes. Vitreous organization meeting our clinically important definition was associated with a 31-fold (confidence interval [CI] 5.37-183.63; P < .0001) and 13-fold (CI 2.97-58.59; P < .0001) increase in the odds for retinal detachment for right and left eyes, respectively. Vitreous hemorrhage defined as clinically important was associated with a 38-fold (CI 2.69-551.19; P = .007) and 15-fold (CI 1.65-144.12; P = .02) increase in the odds for retinal detachment for right and left eyes, respectively. The timing of retinal detachment relative to vitreous hemorrhage was not determined. Prolonged activity of Stage 3 disease or plus disease more than 21 days after treatment was not associated with development of a retinal detachment. CONCLUSIONS: Clinically important vitreous organization and vitreous hemorrhage were predictive for development of a retinal detachment. Evaluation of preemptive reintervention strategies for eyes at highest risk for developing a retinal detachment may be reasonable.

Female↗

PubMed2005

The management of strabismus in adults--II. Patient and provider perspectives on the severity of adult strabismus and on outcome contributors.

PURPOSE: As part of a larger study intended to evaluate the management of strabismus in adults, we documented and compared patient and provider perspectives on the various factors that may contribute to treatment outcome and value of strabismus care. METHODS: By completing a questionnaire, 170 patients with strabismus (ages 19 to 87 years) and 11 strabismus specialists who performed surgery on these patients each indicated the relative weight of several disease- and treatment-related contributors to the outcome and value of care. In addition, each respondent rated the severity of the strabismus before and after surgery. RESULTS: Overall severity ratings improved as a result of surgery. The improvement perceived by the physicians was 5.1 +/- 1.7 on a 10-point scale and was larger than the 2.6 +/- 3.6 points improvement perceived by the patients ( P < 0.001). Patients and physicians expressed different views on the relative contributions to outcome and value (overall P < 0.001). Both groups indicated "the condition," "the physician," and "the procedures" as the largest contributors, but "condition" was perceived as more important by the physicians than by the patients ( P < 0.001), and "physician" was more important to the patients than to the physicians ( P < 0.001). CONCLUSION: Although in approximate agreement on the main contributors to outcome and value, discrepancies exist between perspectives of patients and physicians on the relative weights of those contributors. Public information, education, and counseling may bring these perspectives better in line and ultimately improve both quality and patient satisfaction.

Adult↗

PubMed2005

The management of strabismus in adults--III. The effects on disability.

INTRODUCTION: This is the third article in a series on the various facets of the management of strabismus in adults. Here, we give a broad overview of the types and severity of disability and provide initial validation of an instrument (questionnaire) to assess these disability aspects. METHODS: After undergoing strabismus surgery, 101 patients from 6 centers completed a 6-item questionnaire in which they rated both the before-surgery and after-surgery severity of problems associated with their strabismus, ranging from specific health, daily functioning, social interaction, concerns about the future, and self-image to job-related difficulties. RESULTS: The before-surgery outcomes showed significant variation across the 6 types of problems (P < 0.001), with "specific health" and "daily tasks" yielding the highest problem rating. Patients with diplopia reported more severe problems with "daily tasks" (P = 0.004) and "concerns about the future" (P = 0.026) than patients without diplopia. Overall, all problem ratings declined after surgery (P < 0.001), but patients who were not successfully aligned were left with higher problem ratings on "specific health" (P = 0.005), "daily tasks" (P = 0.003), and "social interaction" (P = 0.024). CONCLUSIONS: The results indicate a wide range of disability aspects in adult patients with strabismus, with moderate differences between patients with or without diplopia. Improvements in disability after surgery, as reflected by these ratings, should be taken into account when assessing the health value of adult strabismus management.

Adult↗

PubMed2005

Retinopathy of prematurity: involution, factors predisposing to retinal detachment, and expected utility of preemptive surgical reintervention.

PURPOSE: To characterize involution of retinopathy of prematurity (ROP) following treatment at threshold, to identify findings during involution that portend development of retinal detachment, and to assess the potential utility of preemptive vitrectomy for eyes with high-risk features. METHODS: The probability of ROP involution and of retinal detachment evolution over time was analyzed in 262 treated eyes of 138 infants in a retrospective observational non-case controlled series. Expected utility of preemptive reintervention in eyes with high-risk features was evaluated using decision analysis. Modifications were devised to enhance classification of advanced ROP. RESULTS: ROP fully involuted in approximately 80% of eyes within 28 days of treatment. Vitreous organization meeting the study's clinically important definition was associated with a 31-fold (5.37 to 183.63; P < .0001) and a 13-fold (2.97 to 58.59; P < .0001) increase in the odds for retinal detachment for right and left eyes, respectively. Vitreous hemorrhage defined as clinically important was associated with a 38-fold (2.69 to 551.19; P = .007) and a 15-fold (1.65 to 144.12; P = .02) increase in the odds for retinal detachment for right and left eyes, respectively. As modeled, an expected utility of 0.85 was calculated for preemptive vitrectomy compared with 0.79 for deferred vitrectomy for eyes with clinically important vitreous organization. CONCLUSIONS: Acute-phase ROP involuted quickly in most eyes. Vitreous organization and vitreous hemorrhage were predictive of eyes that developed a retinal detachment. Decision analysis suggests that preemptive vitrectomy for eyes with vitreous organization meeting specific criteria is not likely to be worse than deferred vitrectomy, and it could be advantageous in some scenarios.

Decision Support Techniques↗

PubMed2004

The effect of off-the-visual-axis retinoscopy on objective refractive measurement.

PURPOSE: To determine the effect of off-axis retinoscopy on objective refractive measurement. DESIGN: Prospective experimental study. METHODS: Eight volunteers underwent cycloplegic retinoscopy of their right eye on-the-visual-axis, and 5, 10, 15, and 20 degrees off-the-visual-axis in adduction. A single masked examiner performed all retinoscopy with random order of the patient and axis refracted. RESULTS: The average spherical retinoscopic value at 0, 5,10,15, and 20 degrees of off-axis alignment was -0.40, -0.90, -1.00, -1.38, and -1.80 diopters, respectively. The average spherical equivalent retinoscopic value obtained for each of the above positions of eye alignment was -0.02, -0.59, -0.45, -0.64, and -0.98 diopters, respectively. The induced cylinder power increased by an average of 3% for each degree of off-axis retinoscopy, though the axis of the cylinder was not predictable. CONCLUSION: Objective refractive measurement by retinoscopy is significantly altered by off-the visual-axis retinoscopy. The induced error may be clinically important even with small degrees of eccentricity.

Adult↗

PubMed2004

Herpes simplex virus keratitis in children.

PURPOSE: To describe the spectrum and recurrence of herpes simplex virus (HSV) keratitis in children and adolescents. DESIGN: Retrospective cohort study. METHODS: Twenty-three patients younger than age 16 years were diagnosed with HSV keratitis at one institution. RESULTS: All children presented with dendritic or punctate epithelial keratitis, and stromal keratitis occurred concurrently with epithelial keratitis in 14 patients (61%). Six patients (26%) had bilateral HSV keratitis. Eleven patients (48%) developed recurrent HSV keratitis at a median of 15 months after the first documented episode. Amblyopia occurred in three children. CONCLUSION: Children with herpetic keratitis may have bilateral ocular involvement and are at risk for recurrent keratitis and amblyopia.

Acyclovir↗

PubMed2004

Corneal thickness in children.

OBJECTIVE: To determine normal central and paracentral corneal thickness measurements in the pediatric population and to determine if these measurements are consistent across different pediatric age groups and different racial groups. DESIGN: Prospective observational case series. METHODS: Pachymetry measurements were performed on 198 eyes of 108 children. The measurements were taken centrally as well as at four paracentral sites 3 mm from the corneal center at the 3, 6, 9, and 12 o'clock positions. The two-tailed t test was used for comparison of the continuous means for values of corneal thickness. Analysis of variance (ANOVA) was performed to determine differences among age and ethnic groups RESULTS: The mean central corneal thickness (CCT) was 549 +/- 46 microm. Paracentral corneal thickness mean values, as measured 3 mm from the corneal center, were as follows: superior, 575 +/- 52 microm; nasal, 568 +/- 50 microm; inferior, 568 +/- 51 microm; and temporal, 574 +/- 47 microm. The mean CCT values were significantly thinner than at each of the mean paracentral points (P < .05 for each comparison, paired t test). Paracentral corneal thickness measurements demonstrated no significant differences between locations (P > .05, variance analysis). The mean CCT +/- SD for each age group was as follows: 6 to 23 months, 538 +/- 40 microm; 2 to 4 years, 546 +/- 41 microm; 5 to 9 years, 566 +/- 48 microm; and 10 to 18 years, 554 +/- 35 microm (ANOVA P = .012). ANOVA performed on central pachymetry values demonstrated no significant differences among racial subgroups. CONCLUSIONS: Pediatric central and paracentral corneal thicknesses increase slowly over time and reach adult thicknesses at 5 to 9 years of age.

Adolescent↗

PubMed2004

Risk factors for treatment failure of anisometropic amblyopia.

PURPOSE: This study sought to explore factors which might predict the lack of vision improvement following therapy of anisometropic amblyopia. METHODS: We retrospectively reviewed the records of 104 children aged 3 to 8 years who had anisometropic amblyopia with a difference in the refractive power between the two eyes of at least 1 diopter, a difference in corrected visual acuity between the two eyes of at least 3 logMAR units, visual acuity in the amblyopic eye of 20/50 or worse, and no ocular structural abnormalities. Patients were treated with either patching or atropine penalization therapy. Patients with strabismus were included. Treatment failure was defined in two ways: (1) functional failure indicating a final visual acuity in the amblyopic eye worse than 20/40 and (2) relative failure indicating less than three lines of logMAR visual acuity improvement regardless of final vision. RESULTS: Failure risk factors were as follows: age above 6 at the onset of treatment (adjusted odds ratio [OR] (95% confidence limits [CL] = 4.69 [1.55, 14.2]), the presence astigmatism of more than 1.50 diopters in the amblyopic eye (adjusted [OR] (95% CL) = 5.78 [1.27, 26.5]), poor compliance with treatment (adjusted [OR] (95% CL) = 5.47 [1.70, 17.6]), and initial visual acuity in the amblyopic eye of 20/200 or worse (adjusted [OR] (95% CL) = 3.79 [1.28, 11.2]). Strabismus was not found to be a significant risk factor. Neither the type or amount of refractive error nor the difference in the refractive power between the two eyes was a significant risk factor for treatment failure. CONCLUSION: Eyes with poor initial visual acuity, the presence of significant astigmatism, and age over 6 years were less likely to achieve successful outcome. The clinical profile of patients with anisometropic amblyopia may be useful in predicting response to therapy, but compliance with treatment has a major effect on response to therapy.

Age Factors↗

PubMed2004

Parent-administered visual acuity testing: is it reliable and can it improve office efficiency?

PURPOSE: To evaluate the accuracy of a parent-administered visual acuity test, using the electronic visual acuity tester (EVA) (JAEB Center, Tampa, FL) and evaluate its use as a means to improve efficiency of office acuity testing. METHODS: This was a prospective experimental study. Part I: Sixty-four children had their visual acuity determined using the EVA, first by their parents and then by an ophthalmic technician. Acuity scores were compared. Part II: Forty-four other children were randomly assigned to one of 2 groups. Group A (parent-prescreen) children had their visual acuity determined first by the parents using the EVA. The visual acuity result in that child was then rechecked by the technician using the Reinforcement Phase and Phase 2 of the Amblyopia Treatment Study (ATS) visual acuity testing protocol. Group B (full ATS protocol) children had their acuity determined by the technician using the full ATS protocol. The number of optotypes presented by the technician in order to determine the acuity in each group was compared. RESULTS: Part I: Reliability of parent-determined visual acuity scores was high (r = 0.91 and 0.81 for right eyes (OD) and left eyes (OS), respectively), with 93% of right eye parent scores and 85% of left eye parent scores within 0.11 logarithm of minimal angle of resolution (logMAR) units (ie, within one line of vision) of the technician score. Part II: The parent prescreen group (Group A) required presentation of 66% fewer optotypes to the OD and 68% fewer optotypes to the OS than the full ATS protocol group (Group B) (OD: P = 5.4 x 10(-18); OS: P = 6.5 x 10(-18)). CONCLUSIONS: Visual acuity testing results by parents using the EVA are reliable. Electronic visual acuity prescreening by parents reduces the number of optotype presentations required to be shown by the technician to accurately determine acuity. Use of a parent-assisted screening system in the waiting room may translate to increased office efficiency.

Caregivers↗

PubMed2004

A simple model for practicing surgery on the nasolacrimal drainage system.

Practicing surgical techniques on models prior to operating on patients can be helpful in developing skills needed to perform surgery proficiently. A simple, inexpensive, and readily available model for instruction and practice of surgical maneuvers on the nasolacrimal drainage system is described.

Child↗

PubMed2004

Involution of threshold retinopathy of prematurity after diode laser photocoagulation.

OBJECTIVE: To characterize the process of involution of threshold retinopathy of prematurity after transpupillary diode laser photocoagulation. DESIGN: Retrospective case series. PARTICIPANTS: Neonates with threshold retinopathy who underwent diode laser photocoagulation of the peripheral avascular retina. METHODS: A retrospective chart review was done of the weekly examination records of infants treated for threshold disease. Features that were studied included the presence of residual stage 3 neovascularization, plus disease, and development of retinal detachment (RD). MAIN OUTCOME MEASURES: Timing of full involution and/or development of an RD. RESULTS: Of 262 eyes of 138 infants treated, full involution without RD was seen in 8%, 43%, 64%, 73%, and 86% of eyes at postoperative weeks 1, 2, 3, 4, and 9+/-3, respectively. Retinal detachments were diagnosed cumulatively in 0%, 1.5%, 4.2%, 6.5%, and 14% of eyes at weeks 1, 2, 3, 4, and 9+/-3, respectively. CONCLUSIONS: Full involution of laser-treated threshold retinopathy of prematurity required more than 2 weeks in more than half of treated eyes. Most RDs were not detected until > or =3 weeks after treatment.

Gestational Age↗

PubMed2004

Strabismus surgery for adults: a report by the American Academy of Ophthalmology.

OBJECTIVE: To describe the effectiveness and safety of surgical treatment of adult patients with strabismus, and to review the reported functional benefits and complications of strabismus surgery for adults. METHODS: A literature search was conducted in September 2001. It was repeated and updated in April 2003, with retrieval of relevant citations. Panel members reviewed the articles and rated them according to their relevance to the topic and methodology. RESULTS: The literature search identified 49 reports that describe the surgical treatment of strabismus in adult patients and meet predetermined review criteria. Of these reports, 2 were of randomized controlled trials, and 1 addressed the primary objective of this review. In this randomized study of adults with strabismus, direct comparison of surgical correction with botulinum toxin A chemodenervation indicated that surgical treatment was superior to botulinum toxin A in realigning the eyes (76.9% vs. 29.4%, P = 0.027). Several large case series of adults with strabismus (level III evidence) with successful surgical realignment rates of 68% to 85% have been reported. Functional benefits of surgical treatment are reported in many patients. These include elimination of diplopia, development of binocular fusion, expansion of binocular visual fields, and improvement of head position. Surgical complications, including new, postoperative diplopia (1%-14%) or scleral perforation (0.8%-1.8%), occur in a minority of patients. Unplanned reoperations (subsequent strabismus procedures that were not anticipated as part of a staged treatment) were needed in up to 21% of patients in large case series of comitant strabismus, and in up to 50% of patients with thyroid ophthalmopathy. CONCLUSIONS: Despite the paucity of level I evidence from randomized controlled trials, the existing literature suggests that surgical treatment of adults with strabismus is safe and effective in improving ocular alignment. In many cases it improves visual function, based largely on level III evidence. Risks include unplanned reoperation, postoperative diplopia, and scleral perforation. Additional level I studies of surgical treatment of adult patients would help to document the effectiveness and substantiate the safety of this treatment.

Adult↗

PubMed2004

Use of the RetCam 120 for fundus evaluation in uncooperative children.

PURPOSE: To report our experience using the RetCam 120 to evaluate suspected retinal pathology in children who did not cooperate for standard in-office examination. DESIGN: Interventional case series. METHODS: We reviewed charts of eight consecutive uncooperative children with suspected fundus abnormalities that were photographed using the RetCam 120 as a routine part of patient care. RESULTS: Three uncooperative children with suspected pathology required RetCam 120 photos because of inadequate fundus examination. Five had pathology or suspected pathology that required more detailed examination. In all of these children, we were able to reach or rule out a diagnosis. CONCLUSION: The Retcam 120 digital fundus camera has utility as an in-office diagnostic tool for fundus examination of poorly cooperative children and may be a good alternative to examination under anesthesia or sedation in selected cases.

Child, Preschool↗

PubMed2004

Accuracy of clinical estimation of abnormal head postures.

PURPOSE: Correct diagnosis and analysis of an abnormal head posture (AHP) is critical in the clinical assessment of patients with strabismus and nystagmus. This study was performed to evaluate the accuracy and precision of clinicians estimating the degree of face turns and head tilts. DESIGN: Experimental simulation study. PARTICIPANTS: Two normal volunteers and 4 pediatric and 1 general ophthalmologists. METHODS: Using a cervical range of motion (CROM) device, single axis head position (chin up, chin down, right and left face turn, and head tilts) were modeled, and clinical estimates of the amount of deviation were estimated by the four ophthalmologists. Each of the 4 examiners estimated 108 single axis AHPs in a randomized and masked pattern. MAIN OUTCOME MEASURES: Accuracy of clinical estimation of AHP, intra- and inter- observer variability, and variability in terms of head position. RESULTS: The examiners tended to overestimate the AHPs by an average of 5 degrees (P less than 0.001). Two "right" positions (right head tilt and face turn) were the worst. The average error was 10 +/-8 degrees for the right tilt and turn positions, while the error for all other positions, excluding these two, averaged 0 +/-10 degrees (P = 0.0001). CONCLUSIONS: Clinical estimation of an AHP by ophthalmologists is in part remarkably accurate, even if imprecise, but some positions, notably right head tilt and right face turn in this study, were significantly overestimated. Objective methods of measuring AHPs such as the CROM may be preferable for these RHT and RFT AHPs and when maximum precision is needed for tracking changing AHPs or deviations.

Diagnostic Techniques, Ophthalmological↗