Suqin Guo

Duane's retraction syndrome☆

Duanes retraction syndrome (DRS) has been a recognized clinical entity for nearly a century. It is a clinically well described ocular disorder consisting of retraction of the globe with narrowing of the lid fissure in attempted adduction, frequent abduction deficiency with variable limitation to adduction, and upshoot and/or downshoot of the affected eye on adduction. Among strabismus patients the incidence of DRS is probably not more than 5%. Most cases are sporadic, but familial cases have been estimated at 10% by most authors. Numerous theories concerning the etiology and pathogenesis of DRS have been proposed, including agenesis of the abducens nucleus, but the majority of investigators concur that the characteristic findings are best explained by a paradoxical innervation of the lateral rectus muscle, which subsequently causes a cocontraction of the horizontal rectus muscles. The frequent association of DRS with other congenital anomalies suggests a teratogenic event occurring between the fourth to eighth week of gestation as an etiological factor. In this review historical aspects and theories of the syndrome are studied and statistical data are compiled and analyzed. Clinical features, differential diagnoses and variants of the syndrome are examined. Testing and treatment objectives are discussed.

Magnetic resonance imaging of aging, accommodating, phakic, and pseudophakic ciliary muscle diameters

PURPOSE: To quantify in vivo accommodative changes in the aging human ciliary muscle diameter in phakic and pseudophakic eyes. SETTING: Department of Surgery/Bioengineering, UMDNJ–Robert Wood Johnson Medical School, Piscataway, and the Institute of Ophthalmology and Visual Science UMDNJ–New Jersey Medical School, Newark, New Jersey, USA. METHODS: Images were acquired from 48 eyes of 40 people between the ages of 22 and 91 years, 1 eye of 32 phakic volunteers and both eyes of 8 patients who had monocular implantation of a single‐piece AcrySof intraocular lens (IOL) (Alcon Laboratories). Images were acquired during physiological accommodation and with accommodation at rest, and the diameter of the ciliary muscle ring was measured. RESULTS: Results show the ciliary muscle remains active throughout life. The accommodative change in its diameter (mean 0.64 mm) (P<.00001) was undiminished by age or IOL implantation. Preliminary data showed that the accommodative decrease in muscle diameter in phakic and pseudophakic eyes was statistically identical. The phakic eyes had a marked decrease in ciliary muscle diameter with advancing age for both accommodative states (P<.000001 and P<.000001), which did not appear to be altered by IOL implantation. The lens equator was constant with age in the unaccommodated human eye, resulting in decreased circumlental space with advancing age in the phakic eyes. CONCLUSION: Although the undiminished ability of the ciliary muscle to decrease its diameter with accommodation can be relied on in strategies for presbyopia correction, even in advanced presbyopia, the decreasing circumlental space and its potential effects on zonular tension must also be considered.

Down Syndrome Clinical Review of Ocular Features

A total of 187 medical records of Down syndrome individuals over a 10-year period were reviewed retrospectively for strabismus, myopia, hyperopia, astigmatism, nystagmus, cataract, glaucoma, and other significant eye findings. This study showed that a higher proportion of these individuals than reported in previous studies had strabismus (57%). Refractive errors of myopia (22.5%), hyperopia (20.9%) and astigmatism (22%) were common. The primary care physician needs to be aware of the specific eye problems of Down syndrome individuals so that he or she may initiate or refer the patient for appropriate ophthalmologic care, because most of the eye findings in Down syndrome are treatable. Significant visual loss, a usually avoidable event in Down syndrome, should occur rarely.

Topical Timolol for Periocular Hemangioma: Report of Further Study

Author Affiliations: Departments of Oncology and Vitreoretina (Dr Khetan) and Ocular Pathology (Drs Biswas and Kumar), Sankara Nethralaya, and Department of Medical Oncology, Apollo Hospitals (Dr Raja), Chennai, India; and Departments of Ophthalmology (Drs AlKharusi and Ganesh) and Child Health (Dr Al-Futaisi), Sultan Qaboos University Hospital, Sultanate of Oman. Correspondence: Dr Khetan, Department of Ocular Oncology, Retina, and Vitreous, Medical Research Foundation, Sankara Nethralaya, 18 College Rd, Chennai, Tamil Nadu 600006, India (drvk@snmail.org). Financial Disclosure: None reported.

Magnetic resonance imaging of the anteroposterior position and thickness of the aging, accommodating, phakic, and pseudophakic ciliary muscle

PURPOSE: To quantify accommodative and age‐related changes in the anteroposterior position and thickness of the ciliary muscle in phakic and pseudophakic eyes. SETTING: Department of Surgery/Bioengineering, UMDNJ–Robert Wood Johnson Medical School, Piscataway; Institute of Ophthalmology and Visual Science UMDNJ–New Jersey Medical School, Newark, New Jersey; MRI Research, Inc., Middleburg Heights, Ohio, USA. METHODS: Magnetic resonance images were taken of phakic and pseudophakic eyes. RESULTS: The cohort comprised 32 phakic volunteers and 8 volunteers with a monocular intraocular lens (IOL) aged 22 to 91 years. No anteroposterior accommodative movement of the ciliary muscle apex occurred in either group. The muscle moved closer to the cornea with advancing age in phakic eyes; IOL implantation returned the muscle to a youthful position. An age‐dependent increase in ciliary muscle anteroposterior thickness occurred that was not mitigated by IOL implantation. Muscle thickness increased with accommodation in only phakic eyes. CONCLUSIONS: Presbyopia‐correction strategies cannot rely on accommodative anterior movement of the ciliary muscle. Forces on the uvea by crystalline lens–pupillary margin contact may increase with accommodation and lens growth, producing accommodative and age‐dependent increases in muscle thickness and significant age‐dependent anterior muscle displacement. Intraocular lens implantation removed these forces, allowing choroidal elasticity to restore the muscle to a youthful position; however, the increase in thickness was permanent and likely due to an age‐dependent increase in connective tissue. This supports the geometric theory of presbyopia development and that the mechanical forces in human accommodation and presbyopia are very different from those in the rhesus monkey model. Financial Disclosure: S. A. Strenk and L. M. Strenk have a proprietary interest in the purpose‐built eye coil. Dr. Guo has no financial or proprietary interest in any material or method mentioned.

Management of the Anterior and Posterior Lens Capsules and Vitreous in Pediatric Cataract Surgery

PURPOSE To review and discuss the advantages and disadvantages of various methods of managing anterior and posterior lens capsules and anterior vitreous in pediatric cataract surgery. METHODS We reviewed the literature related to pediatric cataract surgery on PubMed and subclassified the subject into subtopics for managing the anterior lens capsule, posterior lens capsule, and anterior vitreous. RESULTS After a review of the literature, we summarized the advantages and disadvantages of various approaches related to surgical managements of the anterior lens capsule, posterior lens capsule, and anterior vitreous in pediatric cataract surgery. We discussed recommendations from the literature and commented on our experiences related to the above subtopics. CONCLUSION In the surgical management of pediatric cataract, anterior continuous curvilinear capsulorhexis provides the most reliable and tear-resistant capsular opening. Vitrectorhexis and radiofrequency diathermy, on the other hand, are alternative approaches (depending on the surgeons personal preference). Primary posterior continuous curvilinear capsulorhexis may delay the onset of posterior capsule opacification. Anterior vitrectomy may be necessary to prevent or eliminate the onset of posterior capsule opacification in young children.

Management of pseudophakic cystoid macular edema

Pseudophakic cystoid macular edema (PCME) is a common complication following cataract surgery. Acute PCME may resolve spontaneously, but some patients will develop chronic macular edema that affects vision and is difficult to treat. This disease was described more than 50 years ago, and there are multiple options for clinical management. We discuss mechanisms, clinical efficacy, and adverse effects of these treatment modalities. Topical non-steroidal anti-inflammatory agents and corticosteroids are widely used and, when combined, may have a synergistic effect. Intravitreal corticosteroids and anti-vascular endothelial growth factor (anti-VEGF) agents have shown promise when topical medications either fail or have had limited effects. Randomized clinical studies evaluating anti-VEGF agents are needed to fully evaluate benefits and risks. When PCME is either refractory to medical therapy or is associated with significant vitreous involvement, pars plana vitrectomy has been shown to improve outcomes, though it is associated with additional risks.

Current concepts in the management of periocular infantile (capillary) hemangioma.

Purpose of review To review and evaluate the medical literature on new treatments for periocular infantile (capillary) hemangioma. Recent studies have shown a promising new therapy for infantile hemangioma using nonselective &bgr;-blockers, including oral propranolol and topical timolol. Recent findings Conventional treatments for infantile hemangioma include the use of corticosteroids, laser, surgery, and immunomodulator therapy. Recently, systemic and topical &bgr;-blockers have been used to successfully treat infantile hemangioma. The drugs’ mechanism of action remains uncertain, but plausible theories include vasoconstriction, modulation of pro-survival signal transduction pathways, and endothelial cell apoptosis. Whereas no life-threatening adverse events from &bgr;-blocker treatment have been described, there have been reports of bradycardia, hypotension, bronchospasm, hypoglycemia, and electrolyte disturbances resulting from systemic use of propranolol to treat infantile hemangioma. Sleep and gastrointestinal disturbances have also been frequently reported. Topical timolol application for localized, superficial tumors may confer similar efficacy as oral propranolol while reducing systemic effects. Summary Despite the recent explosion of interest surrounding this novel treatment, current treatment and protocol-monitoring recommendations are based largely on the experience of individual centers. Several randomized controlled studies are currently underway, the results of which will guide future standard-of-care treatment for infantile hemangioma.

Diplopia and Strabismus Following Ocular Surgeries

Postoperative diplopia and strabismus may result from a variety of ocular surgical procedures. Common underlying mechanisms include sensory disturbance, scarring, direct extraocular muscle injury, myotoxicity from injections of local anesthesia or antibiotics, and malpositioning of extraocular muscles by implant materials. The most common patterns are vertical and horizontal motility disturbance. Treatment options include prisms, botulinum, occlusion, or surgery.

Enhanced Visualization of Capsulorhexis With Indocyanine Green Staining in Pediatric White Cataracts

PURPOSE To evaluate the enhancement of the visualization of the anterior lens capsule with indocyanine green (ICG) in pediatric dense, mature cataracts. PATIENTS AND METHODS Six children (10 eyes) 4 to 9 years old with complete, white cataracts underwent ICG-enhanced cataract surgery. RESULTS All of the eyes showed a complete continuous curvilinear capsulorhexis and a well-centered intracapsular implant. No surgical or postoperative complications were encountered. CONCLUSION Staining the anterior capsule with ICG is an excellent way to facilitate performance of an anterior capsulorhexis in pediatric white cataracts.