Constance E. West

Outpatient clinic scheduling: a simulation approach

The process by which outpatients are scheduled for a doctors visit is a crucial determinant of the overall efficiency of the patient flow. The problem at hand consists of determining prioritization (triage) rules so that adequate patient care is guaranteed, resources (provider schedules) are utilized efficiently and a service guarantee can be ensured. We present a simulation framework for the evaluation and optimization of scheduling rules. We outline the basic ingredients of our model, illustrate the kinds of analyses it has enabled us to perform and summarize our experience with a preliminary implementation for the Division of Pediatric Ophthalmology at Cincinnati Childrens Hospital Medical Center. Challenges for adaptations to other settings are also outlined.

Extremely low penetrance of Leber's hereditary optic neuropathy in 8 Han Chinese families carrying the ND4 G11778A mutation.

PURPOSE To investigate the role of mitochondrial haplotypes in the development of Lebers hereditary optic neuropathy (LHON) associated with the ND4 G11778A mutation in Chinese families. DESIGN Eight Han Chinese families with maternally transmitted LHON were studied using clinical, genetic, and molecular evaluations. PARTICIPANTS One hundred sixty-seven subjects from 8 Chinese families with a wide age range and severity of visual impairment. METHODS All subjects underwent the clinical and genetic evaluation, as well as molecular analysis of mitochondrial DNA (mtDNA). MAIN OUTCOME MEASURES The ophthalmologic examinations included visual acuity, visual field examination, visual evoked potentials, and fundus photography. Mitochondrial DNA analysis included the polymerase chain reaction amplification of the entire mtDNA and subsequent sequence determination. RESULTS Eight families exhibited extremely low penetrance of visual impairment, with the average of 13%. In particular, 14 (12 males and 2 females) of 119 matrilineal relatives in these families exhibited the variable severity and age at onset in visual dysfunction. The average age of onset of vision loss was 17 years. Molecular analysis of mtDNA identified the homoplasimic ND4 G11778A mutation and distinct sets of variants belonging to the Asian haplogroups M8a2, D4g2, B4a1c, B5b, N9a1, D4b2b, C, and M7b1. However, there was an absence of secondary LHON-associated mtDNA mutations in these 8 Chinese families. CONCLUSIONS The extremely low penetrance of vision loss in these 8 Chinese pedigrees strongly indicates that the G11778A mutation was itself insufficient to produce a clinical phenotype. The absence of secondary LHON mtDNA mutations suggest that these mtDNA haplogroup-specific variants may not play an important role in the phenotypic expression of the G11778A mutation in those Chinese families with very low penentrace of vision loss. However, nuclear backgrounds and environmental factors seem to be modifying factors for the phenotypic manifestation of the G11778A mutation in these Chinese families.

Leber's Hereditary Optic Neuropathy Affects Only Female Matrilineal Relatives in Two Chinese Families

PURPOSE The purpose of this study was to investigate the role of modifier factors in the expression of Lebers hereditary optic neuropathy (LHON). METHODS Thirty-five subjects from two Han Chinese families with maternally transmitted LHON underwent a clinical and genetic evaluation and molecular analysis of mitochondrial (mt)DNA. RESULTS Matrilineal relatives in the two Chinese families exhibited a wide range of severity in visual impairment, from blindness to nearly normal vision. Very strikingly, all nine affected individuals of 21 matrilineal relatives (13 females/8 males) were female, which translates to 33% and 57% of penetrance for optic neuropathy in the two families. The average age at onset was 22 and 25 years. These observations were in contrast with typical features in many LHON pedigrees that have a predominance of affected males. Molecular analysis of their mtDNAs identified the homoplasmic ND4 G11778A mutation and distinct sets of variants belonging to the Asian haplogroups M1 and M10a. Of other variants, the L175F variant in CO3; the I58V variant in ND6; and the I189V, L292R, and S297A variants in CYTB were located at highly conserved residues of polypeptides. CONCLUSIONS Only female matrilineal relatives with a wide range of penetrance, severity, and age at onset of optic neuropathy in these two Chinese pedigrees showed the involvement of X-linked or autosomal recessive modifier genes in the phenotypic manifestation of the G11778A mutation. Furthermore, mitochondrial haplogroup-specific variants, together with epigenetic and environmental factors, may contribute to the phenotypic manifestation of the primary LHON-associated G11778A mutation in these pedigrees.

Pediatric airbag-associated ocular trauma and endothelial cell loss.

BACKGROUND Airbag-associated ocular trauma among the adult population has been widely reported, but reports of these injuries in children are sparse. Laboratory experiments suggest that airbag-associated ocular trauma may cause endothelial cell loss, but reports of in vivo human endothelial cell counts are anecdotal. METHODS A retrospective chart review was performed of all patients with airbag-associated ocular trauma at a pediatric hospital from 1995 to 2001. From 2001 to 2002, endothelial cell counts were obtained from 9 eyes of airbag-associated ocular trauma subjects and 22 eyes of control subjects. RESULTS Sixteen patients were identified; all had periocular abrasions, edema, and/or ecchymosis. Other ocular injuries included corneal abrasions (n = 9 or 56%), corneal edema (n = 8 or 50%), hyphema (n = 7 or 44%), lens opacities (n = 5 or 31%), and macular scars (n = 2 or 12%). Three eyes of three patients required intraocular surgery. Unilateral visual loss (hand-motions, 20/100) occurred in two patients. A decrease in mean endothelial cell count of 547 cell/mm2 (P =.01) was found in the airbag-associated ocular trauma group eyes when compared with control group eyes. CONCLUSIONS The present study includes the largest reported case series of pediatric airbag-associated ocular trauma. Airbag-associated ocular trauma may necessitate intraocular surgery, may result in permanent visual loss, and may cause endothelial cell loss in pediatric patients.

Reliability of grading retinal hemorrhages in abusive head trauma

PURPOSE To study the intra- and inter-observer reliability of pediatric ophthalmologists in grading retinal hemorrhages in abusive head trauma. METHODS Pediatric ophthalmologists attending the 2009 annual meeting of the American Association for Pediatric Ophthalmology and Strabismus participated in an onsite survey. The participants were required to compare a collection of fundus photographs of patients with abusive head trauma to two standardized photographs, A and B. Participants graded photographs as normal (no retinal hemorrhages), better than A but not normal, same as A, between A and B, same as B, or worse than B. The survey was divided into four parts: part 1 consisted of 20 photographs to be graded; part 2 was a questionnaire about participants professional experience; part 3 consisted of 20 photographs to be graded (including 15 graded in part 1 but reordered); and part 4 asked about the criteria used to grade the photographs. RESULTS Of the 95 participants, 92 (97%) were licensed physicians with a mean of 14 years in practice. The intra-rater reliability was found to be high, with overall average of 85% pre- and post-agreement on the common pictures. Kendalls coefficient of concordance was used as the statistical measure of inter-rater reliability and had a high value (0.82). CONCLUSIONS Pediatric ophthalmologists showed high intra- and inter-observer reliability in grading retinal hemorrhages in abusive head trauma.

Surgical management of infantile cataracts in dystrophic epidermolysis bullosa

Epidermolysis bullosa describes a group of mechanobullous skin diseases that result in the formation of blisters with little or no trauma. In dystrophic epidermolysis bullosa, the eyelid skin and ocular surface are commonly affected; however, infantile cataracts are a rare occurrence. A 7-month-old boy with dense bilateral cataracts and nystagmus underwent cataract extraction, lens implantation, and limited vitrectomy with the use of specialized techniques to reduce iatrogenic skin and ocular surface complications. No iatrogenic skin or ocular surface complications were observed postoperatively. At 24 months of age, the child demonstrated improved visual function.

Refractive Error in Children

• Emmetropization is guided by genetics but modified by environmental influences. No definitive treatments have emerged.

Displacement of optical centers in over-the-counter readers: a potential cause of diplopia

Induced prism in spectacle lenses, which may result from inadvertent displacement of optical centers, may worsen an existing heterophoria or even cause diplopia, yet over-the-counter reading glasses (OTC readers) are not always assessed by clinicians when evaluating patients with diplopia or asthenopia. To gauge the magnitude of this potential problem, we used a focimeter and prescription aligner to assess the frequency and extent of clinically significant manufacturing variations in a random selection of 160 OTC readers. The optical centers were vertically displaced by ≥3 mm in 11%, with a maximum displacement of 7 mm in 1 pair. Average interpupillary distance was 64 mm (range, 58-74.5 mm), with interpupillary distance outside the normal range of 60-70 mm in 5%. Monocular pupillary distance was asymmetric by ≥5 mm in 4%. A 0.75 D power difference between lenses was measured in one pair of OTC readers. Some OTC readers have misaligned optical centers and other manufacturing defects that are of a magnitude sufficient to exacerbate a heterophoria and cause asthenopia or diplopia.

Surgical Outcomes Following Repair of Traumatic Retinal Detachments in Cognitively Impaired Adolescents With Self-Injurious Behavior

PURPOSE To assess anatomic outcomes following repair of traumatic retinal detachment (RD) among a cohort of cognitively impaired adolescents with self-injurious behaviors. METHODS Main outcome measures in this retrospective, consecutive, interventional case series were retinal attachment and postoperative complications. RESULTS Complete retinal reattachment was initially achieved in all 9 eyes of 9 patients. Six (67%) eyes had chronic RD at initial presentation, and 7 (78%) patients had limited vision from inoperable RD in the fellow eye. Proliferative vitreoretinopathy led to recurrent RD in 4 (44%) eyes at a mean of 2.7 months. Final total or partial retinal attachment was achieved in 6 (67%) and 3 (33%) eyes, respectively, with a mean of 1.7 procedures over a mean follow-up of 22.4 months. Silicone oil emulsification led to progressive glaucoma in 4 (50%) of 8 eyes in which it was used, requiring silicone oil exchange (2 eyes) or removal (2 eyes). Recurrent RD developed in both eyes from which silicone oil was removed despite prior retinal anatomic stability for more than 6 months. CONCLUSION Cognitively impaired adolescents with self-injurious behaviors typically presented with severe visual impairment from chronic traumatic RD in one or both eyes. Despite initial anatomic success, formation of proliferative vitreoretinopathy and further ocular trauma from continued self-injurious behaviors led to a high rate of recurrent RD. Long-term silicone oil tamponade may prevent recurrent RD in this challenging scenario but is associated with vision loss from progressive glaucoma and corneal decompensation.