Richard A. Saunders

Screening Examination of Premature Infants for Retinopathy of Prematurity

This statement revises a previous statement on screening of preterm infants for retinopathy of prematurity (ROP) that was published in 2006. ROP is a pathologic process that occurs only in immature retinal tissue and can progress to a tractional retinal detachment, which can result in functional or complete blindness. Use of peripheral retinal ablative therapy by using laser photocoagulation for nearly 2 decades has resulted in a high probability of markedly decreasing the incidence of this poor visual outcome, but the sequential nature of ROP creates a requirement that at-risk preterm infants be examined at proper times and intervals to detect the changes of ROP before they become permanently destructive. This statement presents the attributes on which an effective program for detecting and treating ROP could be based, including the timing of initial examination and subsequent reexamination intervals.

Management of Strabismus with Botulinum A Toxin

Three hundred eight patients with strabismus were treated with botulinum A toxin (Oculinum) chemodenervation; 153 were followed by the authors for at least 6 months. In this study group, 97 received botulinum A toxin injections as the primary method of treatment of their ocular deviation. Fifty-six received injections after traditional extraocular muscle surgery. Botulinum A toxin was useful for management of patients with recent surgical overcorrections and for management of some patients with sixth cranial nerve palsy. Chemodenervation of an extraocular muscle was not as successful as traditional strabismus surgery for treatment of infantile esotropia and other comitant deviations. Botulinum A toxin injection was ineffective in patients who had restrictive strabismus. This drug has limited application in the management of patients with strabismus.

Anterior segment ischemia after strabismus surgery

Surgery on the extraocular muscles of the eye is generally consisted a safe procedure which is associated with low morbidity and mortality. While infrequent, intra-operative complications occasionally occur. Tenotomy of multiple rectus muscles can result in interruption of the vascular supply to the anterior segment of the eye. Anterior segment ischemia (ASI) may result. This article reviews the complication of anterior segment ischemia as a result of strabismus surgery and its potential for producing permanent visual loss.

The management of strabismus in adults—I. clinical characteristics and treatment

INTRODUCTION This is the first in a series of articles intended to evaluate the management of strabismus in adults, including clinical outcomes and the quality, cost, and value of treatment from the perspectives of patients and health care providers. Here we present clinical characteristics, complexity of surgery, treatment success, and resolved complaints in a group of adult patients who underwent strabismus surgery. METHODS This is a multicenter retrospective study analyzing the type and amount of ocular misalignment before and after surgery in adult patients with strabismus onset before (BVM, or age < 9 years) or after (AVM, or age >/= 9 years) visual maturation. Success was evaluated in terms of alignment, motility, and the presence of diplopia; subjective success was measured in terms of resolved complaints. The complexity of surgery was determined using the Intensity/Complexity Index and compared with success rates. RESULTS Data are reported on 299 patients (90 BVM and 145 AVM) whose eyes were successfully aligned in 63% of the BVM cases and 81% of the AVM cases. Subjective complaints resolved at similar rates in the BVM and AVM subgroups. Successful alignment was not correlated with complexity of surgery, but motility and sensory success rates were correlated with complexity of surgery. CONCLUSION Within each of the BVM and AVM subgroups, this study of adult strabismus showed similar surgical success rates compared with published data. This qualifies these patient groups as clinically typical of adults undergoing strabismus surgery. Additional studies will expand on health value analyses.

Anterior Segment Ischemia after Three Rectus Muscle Surgery

Nine patients underwent simultaneous or staged detachment of the vertical and medial rectus muscles in the treatment of sixth nerve palsy or Duanes retraction syndrome. In five adult patients (34, 35, 41, 45, and 65 years of age), clinically significant anterior segment ischemia developed postoperatively. Known medical risk factors were present in only one case. With the exception of corectopia, there were no apparent sequelae and all involved eyes returned to preoperative visual acuity within 9 weeks of surgery. Anterior segment ischemia may be a frequent complication of strabismus surgery in adult patients when the superior, inferior, and medial rectus muscles are detached from the globe.

Anterior segment ischemia syndrome following rectus muscle transposition.

Two patients developed clinically significant anterior segment ischemia following full tendon transposition of the superior and inferior recti muscles nine and 20 years after they underwent horizontal rectus muscle surgery. Ipsilateral carotid artery ligation in one patient and possible hyperlipoproteinemia type II in the other were discovered postoperatively and may have contributed to the circulatory disturbances observed. In adult patients with paretic strabismus, the most important function of the paretic muscle may be maintenance of circulation to the anterior segment of the eye.

Mechanized anterior capsulectomy as an alternative to manual capsulorhexis in children undergoing intraocular lens implantation

BACKGROUND Although manual capsulorhexis is an ideal anterior capsulectomy technique for adults, it is more difficult to perform in very young eyes because the capsular bag is more elastic. Our mechanized anterior capsulectomy technique has compared favorably with manual capsulorhexis in the laboratory using autopsy eyes. We now report the results of circular mechanized anterior capsulectomy in consecutive pediatric patients receiving a posterior chamber intraocular lens (IOL) after cataract extraction. METHODS Twenty eyes of 17 consecutive patients between 6 months and 13 years of age underwent a mechanized anterior capsulectomy followed by IOL implantation into the capsular bag. The integrity of the anterior capsular edge was evaluated at the completion of capsulectomy, prior to IOL insertion, and at the end of surgery. RESULTS A single radial tear developed in three eyes (15%) of two patients (12%). In the remaining 17 eyes (85%), an intact circular capsulectomy edge was verified at the completion of the mechanized capsulectomy, at the end of IOL insertion, and at the completion of surgery. Complete in-the-bag capsular fixation of the IOL was accomplished in all 20 eyes. Both patients who sustained radial tears were older children (age 11 years). All IOLs remain well centered behind a smooth circular anterior capsular edge after a minimum follow up of 6 months. CONCLUSION A mechanized anterior capsulectomy technique can produce a circular capsular opening that resists tearing during lens aspiration and IOL insertion. The vitrector-cut capsulectomy performed well even in the youngest patients in whom manual capsulorhexis would have been difficult to control.

The Effect of Anemia on Retinopathy of Prematurity in Extremely Low Birth Weight Infants

OBJECTIVE: Numerous risk factors for development of retinopathy of prematurity (ROP) in very low birth weight infants have been identified in the literature. However, the role of anemia in the development of ROP has not been adequately addressed.STUDY DESIGN: We retrospectively examined the medical records of all infants weighing ≤800 g who were admitted to a university hospital between July 1, 1992 and December 30, 1997. Highest and lowest hemoglobin and hematocrit values and the number of blood transfusions were recorded at each week of life during hospitalization. Gestational age at birth, birth weight, race, sex, oxygen status, history of bronchopulmonary dysplasia, length of hospital stay, and sepsis were also identified as potential risk factors. Data were analyzed using logistic regression to adjust for these confounding variables.RESULTS: Infants were grouped according to ROP status in the following manner: stage 0 to 1 ROP, stage 2 ROP, and stage 3 to threshold ROP. Sex, gestational age at birth, bronchopulmonary dysplasia, ventilator days, length of hospital stay, and number of blood transfusions were significantly associated with severity of ROP by univariate analysis. Using a logistic regression model, only gestational age (p=0.007) and number of blood transfusions (p=0.04) remained statistically significant.CONCLUSIONS: Anemia did not affect severity of ROP as an independent risk factor. However, the number of blood transfusions did affect the highest stage of ROP in this group of premature infants. Infants who remained severely anemic (Hgb≤8 g/dl or Hct≤25%) for longer periods of time developed milder ROP than less anemic infants.

Retinopathy of prematurity in infants with birth weights greater than 1250 grams

PURPOSE To determine whether severe retinopathy of prematurity (ROP) occurs in infants whose birth weights exceed 1250 g. METHODS We retrospectively reviewed the medical records of 1118 premature infants with birth weights > 1250 g, who were referred for screening examinations for ROP, to determine the severity of ROP observed. We then cross-tabulated these data with each infants estimated gestational age and birth weight. Finally, we applied currently recommended screening guidelines retrospectively to determine whether they would have identified infants who had developed severe disease and who were subsequently treated. RESULTS Stage 3 ROP was detected in infants with estimated gestational ages up to and including 32 weeks and birth weights up to and including 1874 g. A total of 26 of the participants received laser treatment for threshold ROP. Seven of these infants would not have been referred for screening according to current guidelines. CONCLUSIONS Current screenings guidelines may fail to detect severe ROP in larger, more mature infants.

DUANE RETRACTION SYNDROME

Duane retraction syndrome (DRS) consists of deficient horizontal eye movements, eyelid retraction, palpebral fissure narrowing, and abnormal vertical eye movements. Most cases are sporadic and unilateral (usually left side) with a slight female predominance. Several associated ocular and systemic conditions have been described in DRS patients. In most cases, the abducens nucleus and nerve are absent or hypoplastic, and the lateral rectus muscle is innervated by a branch of the oculomotor nerve. However, there may be contributing mechanical abnormalities. Type I DRS (primary gaze position esotropia with limitation of abduction) comprises the majority of cases. Approximately 50% of type I DRS patients are orthophoric in primary gaze. Esotropia is the most common type of strabismus encountered, and characteristic up shoots and down shoots occur in adduction. Surgical intervention has gradually become more popular in order to improve the primary gaze alignment and mitigate some of the associated abnormalities in ocular motility. However, patients are rarely rendered clinically normal, and limited expectations are appropriate.