Multispecialty Management of Metastatic Colon Adenocarcinoma Involving the Extraocular Muscles: Primary Excision and Simultaneous Treatment of Strabismus With a Review of the Literature

Metastatic colon adenocarcinoma involving the extraocular muscles is extremely rare. It usually develops following the diagnosis of the systemic disease and therefore, management and treatment require a multispecialty approach. Within this manuscript, we provide a summary of cases of orbital metastasis secondary to colon cancer. We further discuss a detailed case of a 42-year-old male patient who developed recent-onset diplopia in the left gaze. Orbital CT imaging showed a localized, well-circumscribed enlargement of the right medial rectus muscle. The biopsy of the right medial rectus showed adenocarcinoma originating from the gastrointestinal system. Further workup revealed colon adenocarcinoma with multiple metastatic sites. The patient started systemic chemotherapy. After 2 months of chemotherapy (5-fluouracil, oxaliplatin, irinotecan, and leucovorin), all systemic metastatic sites regressed; however, his medial rectus muscle continued to grow, causing compressive optic neuropathy. The patient underwent excisional biopsy of the right medial rectus muscle with simultaneous repair of the strabismus with transposition of superior and inferior recti muscles. He continued with systemic chemotherapy. Follow up in 1 year revealed no local orbital tumor recurrence with excellent visual acuity and no diplopia in primary gaze.

Resolution of cyclic esotropia with 5-year follow-up after brief Fresnel prism treatment

Cyclic esotropia is a rare form of strabismus that is characterized by a recurring esotropic deviation, usually with a 48-hour cycle. On esotropic days, the patient has a constant deviation with suppression, followed by a day with straight eyes and good binocular function. We report a case of cyclic esotropia in which the cycling resolved with 2 months of Fresnel prism for the amount of the distance deviation on her "straight" days. Five years later, with low plus hyperopic correction, she remains with a stable esophoria and normal stereopsis.

Comparison of Unilateral and Bilateral Surgical Approaches for the Treatment of Age-Related Divergence Insufficiency Esotropia

PURPOSE

Age-related divergence insufficiency-esotropia (ARDIE) is characterized by greater esodeviation at distance than near. This study aims to compare the outcomes of unilateral and bilateral surgical approaches.

PATIENTS AND METHODS

Sixty-two cases treated at the Kellogg Eye Center, the University of Michigan, from 1995 to 2018 were retrospectively reviewed. One surgeon used unilateral procedures including unilateral medial rectus recession (n = 24, group 1) or unilateral recession-resection (n = 18, group 2) with an adjustable suture. Another surgeon used bilateral medial rectus recession with fixed sutures (n = 20, group 3).

RESULTS

For patients with distance esodeviation <15∆, postoperative distance deviations in both group 1 and group 3 were not statistically different (p = .352). For patients with esodeviations 15-20∆, postoperative distance deviations in all 3 groups were also not statistically different (p = .142). Similarly, patients with deviations >20∆ did not show significantly different postoperative distance alignment (p = .082) between group 2 and 3. Overall, group 2 had the highest overall success rate (90%) (mean at distance = 1.17∆ exodeviation, at near = 2.33∆ exodeviation).

CONCLUSION

Both unilateral medial rectus recession ± lateral rectus resection and bilateral medial rectus recession surgical approaches produced similar favorable outcomes in ARDIE.

A 2020 Update on 20/20 X 2: Diplopia after Ocular Surgery: Diplopia after Orbital Surgery

In a review of 261 strabismus surgeries performed after previous orbital surgery, it was found that diplopia associated with orbital surgery most commonly occurs after orbital decompression for thyroid eye disease or after repair of orbital fractures. Other types of orbital surgery account for only a small number of cases. While the orbital surgery itself may contribute to the development or worsening of diplopia, in most cases, the post-operative strabismus is largely attributable to the underlying disease or trauma. However, in a small number of cases, a specific surgical misadventure can result in diplopia.

Novel TMEM98, MFRP, PRSS56 variants in a large United States high hyperopia and nanophthalmos cohort

Nanophthalmos is a rare condition defined by a small, structurally normal eye with resultant high hyperopia. While six genes have been implicated in this hereditary condition (MFRP, PRSS56, MYRF, TMEM98, CRB1,VMD2/BEST1), the relative contribution of these to nanophthalmos or to less severe high hyperopia (≥ + 5.50 spherical equivalent) has not been fully elucidated. We collected probands and families (n = 56) with high hyperopia or nanophthalmos (≤ 21.0 mm axial length). Of 53 families that passed quality control, plausible genetic diagnoses were identified in 10/53 (18.8%) by high-throughput panel or pooled exome sequencing. These include 1 TMEM98 family (1.9%), 5 MFRP families (9.4%), and 4 PRSS56 families (7.5%), with 4 additional families having single allelic hits in MFRP or PRSS56 (7.5%). A novel deleterious TMEM98 variant (NM_015544.3, c.602G>C, p.(Arg201Pro)) segregated with disease in 4 affected members of a family. Multiple novel missense and frameshift variants in MFRP and PRSS56 were identified. PRSS56 families were more likely to have choroidal folds than other solved families, while MFRP families were more likely to have retinal degeneration. Together, this study defines the prevalence of nanophthalmos gene variants in high hyperopia and nanophthalmos and indicates that a large fraction of cases remain outside of single gene coding sequences.

Age at Craniosynostosis Surgery and Its Impact on Ophthalmologic Diagnoses: A Single-Center Retrospective Review

BACKGROUND

Ocular abnormalities in craniosynostosis are a persistent concern for patients and providers, and some surgeons feel that early surgical intervention for synostosis alleviates the progression of ophthalmologic abnormalities. In contradistinction, the authors hypothesize that operating early will have no bearing on postoperative ophthalmologic outcomes.

METHODS

Single-suture craniosynostosis patients who underwent surgical correction between 1989 and 2015 were reviewed. Patients with multisuture craniosynostosis, syndromic diagnoses, no preoperative ophthalmology evaluation, and less than 2 years of follow-up were excluded. Logistic regression was used to determine odds of preoperative and postoperative ophthalmologic abnormalities by age, while controlling for patient-level covariates.

RESULTS

One hundred seventy-two patients met inclusion criteria. The median age at surgery was 10 months (interquartile range, 7 to 12.9 months). Increasing age at the time of surgery was associated with increased odds of preoperative ophthalmologic diagnoses (OR, 1.06; p = 0.037) but not postoperative diagnoses (OR, 1.00; p = 0.91). Increasing age at surgery was also not associated with increased odds of ophthalmologic diagnoses, regardless of timing (OR, 1.04; p = 0.08). Patients with coronal synostosis (OR, 3.94; p = 0.036) had significantly higher odds of preoperative ophthalmologic diagnoses. Patients with metopic (OR, 5.60; p < 0.001) and coronal (OR, 7.13; p < 0.001) synostosis had significantly higher odds of postoperative ophthalmologic diagnoses.

CONCLUSIONS

After reviewing an expansive cohort, associations of both overall and postoperative ophthalmologic diagnoses with age at surgery were not found. The authors' findings thus run counter to the theory that early surgical intervention lessens the likelihood of postoperative ophthalmologic diagnoses and improves ophthalmologic outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Variants in myelin regulatory factor (MYRF) cause autosomal dominant and syndromic nanophthalmos in humans and retinal degeneration in mice

Nanophthalmos is a rare, potentially devastating eye condition characterized by small eyes with relatively normal anatomy, a high hyperopic refractive error, and frequent association with angle closure glaucoma and vision loss. The condition constitutes the extreme of hyperopia or farsightedness, a common refractive error that is associated with strabismus and amblyopia in children. NNO1 was the first mapped nanophthalmos locus. We used combined pooled exome sequencing and strong linkage data in the large family used to map this locus to identify a canonical splice site alteration upstream of the last exon of the gene encoding myelin regulatory factor (MYRF c.3376-1G>A), a membrane bound transcription factor that undergoes autoproteolytic cleavage for nuclear localization. This variant produced a stable RNA transcript, leading to a frameshift mutation p.Gly1126Valfs*31 in the C-terminus of the protein. In addition, we identified an early truncating MYRF frameshift mutation, c.769dupC (p.S264QfsX74), in a patient with extreme axial hyperopia and syndromic features. Myrf conditional knockout mice (CKO) developed depigmentation of the retinal pigment epithelium (RPE) and retinal degeneration supporting a role of this gene in retinal and RPE development. Furthermore, we demonstrated the reduced expression of Tmem98, another known nanophthalmos gene, in Myrf CKO mice, and the physical interaction of MYRF with TMEM98. Our study establishes MYRF as a nanophthalmos gene and uncovers a new pathway for eye growth and development.

The effect of oral statin therapy on strabismus in patients with thyroid eye disease

BACKGROUND

Statins, known to possess anti-inflammatory characteristics, have recently been identified as potentially reducing the risk of developing thyroid eye disease (TED) in Graves disease patients. The current study investigates the effect of oral statin therapy on strabismus related to TED.

METHODS

This is a retrospective review of patients with a diagnosis of both TED and restrictive strabismus. Oral statin users and nonusers were analyzed for smoking status, previous radioactive iodine, thyroidectomy, number of decompressions, motility restriction, amount of strabismus, number of surgeries, surgical dose, and number of muscles involved on radiography.

RESULTS

Thirty patients (average age, 63.9 years; 50% male; 59% current/former smokers) were included: 12 statin users and 18 nonusers. Statin users averaged fewer decompressions (1.3 in users vs 2.4 in nonusers [P = 0.04]). Statin users on average had 15 mm of total strabismus surgery compared with 21.4 mm in the nonuser group (P = 0.09) and had fewer muscles involved radiographically (4.3 vs 5.1 [P = 0.08]) CONCLUSIONS: Compared to nonusers, statin users tended to have fewer decompressions, less restriction, fewer surgeries, and fewer muscles involved despite having more current smokers (36% vs 5%), more males, more RAI, and fewer thyroidectomies, all of which are associated with worse TED. In our cohort of patients with TED and strabismus, statin therapy significantly reduced the number of orbital decompressions. Oral statin therapy also trended toward reducing the number and amount of strabismus surgeries as well as radiographic indication of muscle involvement, although these did not meet statistical significance.

Surgical Management of Ophthalmoplegia

Surgical management-depending upon the severity of the ophthalmoplegia-ranges from restorative to palliative. In paresis with reasonable residual muscle function and ductions, the goal of the surgery is not only to restore single vision in primary position but also to provide a relatively normal field of single binocular vision. With complete paralysis of a single muscle or more than one muscle served by a single cranial nerve (third), in addition to conventional recess or resect surgery, the transposition of still-functioning muscles is often needed to obtain a durable result and restore at least some field of single binocular vision. In complete ophthalmoplegia, the benefits of the surgery are limited; but even in these cases, surgery can often reduce the need for an awkward head posture and improve appearance.

Why strabismus surgery works: the legend of the dose-response curve

BACKGROUND

The dose-response relationship has historically been regarded as an important approach to improve the success of strabismus surgery. The purpose of this study was to explore the role of preoperative deviation, in addition to the amount of surgery, as a predictor of the response to strabismus surgery.

METHODS

Dose-response data from a variety of sources are analyzed in a multiple linear regression model with both preoperative deviation and surgical dose as independent variables. P values and partial correlations from these regressions are used to investigate the relative contribution of each factor.

RESULTS

These analyses consistently show that preoperative deviation is statistically a better predictor of the response to surgery than the amount of surgery. In data sets where one factor is constant, preoperative deviation alone accounts for 78%, and the amount of surgery alone accounts for 46% of the variance of the surgical response.

CONCLUSIONS

The importance of preoperative deviation as an independent variable implies a biologic response to strabismus surgery that tends to produce more change in alignment when the deviation is large and less when it is small. The strong association of amount of surgery with surgical outcome in bivariate analysis studies may be an artifact of making the amount of surgery a strict function of the preoperative deviation. Because of its lesser role as a predictor, accuracy of preoperative deviation measurement upon which the amount of surgery is based, refinement of the dose-response curve, or use of adjustable sutures may have less potential to improve surgical outcome than generally believed.

The Necessity of Amblyopia

A general property of nervous system development is that correlated activity is used to organize topographic projections. This correlated activity is typically produced by electrical coupling of adjacent neurons; however, electrical coupling is not possible for retinal ganglion cells in separate eyes that need to be precisely mapped to the same place in the brain. This forces the visual system to rely on environmental stimuli to produce the correlated activity that drives the development of binocularity, with amblyopia as necessary consequence when visual experience is abnormal. The characteristic visual deficits in both the amblyopic and the sound eyes can be understood in the context of these normal developmental processes. The auditory system provides another example-where precise connections between paired sense organs must rely on environmental stimuli for normal development-in which the analogous condition of amblyaudia occurs.

Small Deviations: Vertical, Horizontal, and Combined

INTRODUCTION AND PURPOSE

Symptomatic, small-angle strabismus is largely an acquired problem of adults that has previously been managed with prism spectacles. This paper will explore surgical options that are becoming increasingly popular.

METHODS

The special issues that confound surgical treatment of small-angle strabismus are considered. Surgical procedures described in the literature and in the author's experience that address these issues are reviewed.

RESULTS

Several recently described surgical techniques show promise for treatment of small-angle strabismus in adults. Their use is illustrated in a case report. Review of the author's practice shows a rapid increase in surgery for small-angle strabismus.

CONCLUSIONS

Surgical strategies for small deviations are increasingly important to meet the spectacle-free expectations of our adult patients.

One Year of Pediatric Ophthalmology and Strabismus Research in Review

PURPOSE

To highlight recent advances in amblyopia and strabismus.

DESIGN

Literature review.

METHODS

A literature search of articles published in the English language was performed in PubMed or MEDLINE between May 2012 and April 2013 using the terms amblyopia or strabismus. Articles deemed relevant were selected.

RESULTS

The review highlights articles that increase our understanding of strabismus and amblyopia as well as newer treatment strategies.

CONCLUSIONS

The review highlights some new information and possible future advances in amblyopia and strabismus.

Long-standing, large-angle exotropia in adults

INTRODUCTION AND PURPOSE

This study examines the sensory and motor results in adult patients with large-angle exotropia treated with nonadjustable bilateral recess-resect procedures.

METHODS

A consecutive series of adult patients undergoing four-muscle surgery for exotropia ≥ 50(Δ) with no previous surgery were identified by retrospective medical record review. All patients had nonadjustable symmetric bilateral medial rectus resections and bilateral lateral rectus recessions performed between 1995 and 2006. Data on postoperative alignment, stereoacuity, and the presence or absence of diplopia were collected.

RESULTS

Eight patients met the inclusion criteria. Seven of eight patients required only one surgical procedure for correction of the exotropia with final postoperative deviations within 10(Δ) of orthophoria. One patient required reoperation resulting in a final postoperative measurement of 10(Δ) of esotropia. At final examination, no patient reported diplopia. Four of eight patients had postoperative stereoacuity ranging from 200 to 40 seconds of arc.

CONCLUSIONS

Long-standing, presumably constant, large-angle exotropia does not preclude the recovery of stereopsis after surgical alignment. Permanent postoperative diplopia did not occur in our series. In spite of the large deviations, non-adjustable surgery produces good alignment in most cases, possibly because these patients retain some fusion ability.

Management of binocular diplopia due to maculopathy with combined bangerter filter and fresnel prism

PURPOSE

To describe treatment of binocular diplopia due to maculopathy with a combination of Bangerter foil and Fresnel prism. Methods and Case Report: A protocol for prescribing a combination of Bangerter foil and Fresnel prism is described. A series of three patients in whom a Bangerter foil or prism alone were ineffective for binocular diplopia due to maculopathy, along with a detailed case report of one of these patients, illustrates how a combination of both were used to treat the diplopia.

CONCLUSIONS

Fogging is presumed to relieve binocular diplopia due to maculopathy by inducing a functional central scotoma in the affected eye. In some patients, prism correction is needed in addition to a Bangerter foil to eliminate diplopia, possibly by impoving superimposition of the scotoma in the affected eye and the fovea of the sound eye.

Recurrent orbital schwannomas: clinical course and histopathologic correlation

Background

Schwannomas are slow-growing typically encapsulated tumors composed of differentiated Schwann cells, the primary class of peripheral glial cells. Complete excision is the treatment of choice for orbital schwannomas that cause pain, disfigurement, diplopia, or optic neuropathy. The presence of multiple schwannomas in a single patient suggests possible association with neurofibromatosis type 2 (NF2) or schwannomatosis.

Case presentation

We present 2 patients who experienced recurrent orbital schwannoma without evidence for neurofibromatosis. The recurrence in one patient, a 59-year old man, occurred 6 years after complete excision of the initial tumor. This recurrence consisted of 2 independent tumors in the same orbit. The recurrence in the second patient, a 5 year-old girl, occurred multiple times within days to weeks of partial excisions until eventually a complete excision was performed.

Conclusion

The clinical history, histopathologic features and particularly the intraoperative findings suggest that the 59 year old man suffers from orbital schwannomatosis, while the rapid recurrence in the second patient correlated with the cellular features of her plexiform schwannoma. Hence, the recurrence in each patient is linked to a different etiology, with implications for treatment and patient counseling given the difficulty in treating orbital schwannomatosis. To our knowledge, this is the first description of isolated orbital schwannomatosis.

Long-term Outcomes of Undercorrection Versus Full Correction After Unilateral Intraocular Lens Implantation in Children

PURPOSE

To evaluate the impact of full correction vs undercorrection on the magnitude of the myopic shift and postoperative visual acuity after unilateral intraocular lens (IOL) implantation in children.

DESIGN

Retrospective case control study.

METHODS

The medical records of 24 children who underwent unilateral cataract surgery and IOL implantation at 2 to <6 years of age were reviewed. The patients were divided into 2 groups based on their 1-month-postoperative refraction: Group 1 (full correction) -1.0 to +1.0 diopter (D) and Group 2 (undercorrection) ≥+2.0 D. The main outcome measures included the change in refractive error per year and visual acuity for the pseudophakic eyes at last follow-up visit. The groups were compared using the independent groups t test and Wilcoxon rank sum test.

RESULTS

The mean age at surgery (Group 1, 4.2±0.9 years, n=12; Group 2, 4.5±1.0 years, n=12; P=.45) and mean follow-up (Group 1, 5.8±3.7 years; Group 2, 6.1±3.5 years; P=.69) were similar for the 2 groups. The change in refractive error (Group 1, -0.4±0.5 D/y; Group 2, -0.3±0.2 D/y; P=.70) and last median logMAR acuity (Group 1, 0.4; Group 2, 0.4; P=.54) were not significantly different between the 2 groups.

CONCLUSIONS

We did not find a significant difference in the myopic shift or the postoperative visual acuity in children aged 2 to <6 years of age following unilateral cataract surgery and IOL implantation if the initial postoperative refractive error was near emmetropia or undercorrected by 2 diopters or more.

Are amblyopia treatments really all equal? Is that even the right question?

A series of Pediatric Eye Disease Investigator Group amblyopia treatment studies have concluded that the difference between patching and atropine penalization is inconsequential, and that there is no statistically significant difference between various amounts of prescribed patching. These results, representing mean behavior of groups of amblyopia patients, suggest that a broader range of initial treatments are appropriate than many previously believed; however, it is less clear how this informs treatment in individual cases.

Management of paretic vertical deviations

Paretic vertical deviations are characterized by complex patterns of incomitance that make them some of the most challenging strabismus problems to treat. Optimum results are obtained by performing surgery on those muscles, selected from among the eight cyclovertical muscles in the two eyes, that minimize the incomitance. In superior oblique paresis the additional factors of torticollis and torsion need to be addressed and aberrant regeneration can alter the surgical plan in third nerve paresis.

Evolution of postoperative astigmatism after large incision PMMA lens implantation in children

PURPOSE

To investigate the evolution of postoperative astigmatism after cataract extraction and lens implantation in children through a 6.5 mm limbal incision.

METHODS

This is a retrospective longitudinal study of consecutive pediatric patients with adequate follow-up who underwent cataract extraction with intraocular lens implantation through a 6.5 mm limbal incision. Preoperative and 3-month postoperative astigmatism and spherical equivalent were compared.

RESULTS

A total of 92 eyes of 73 children met the inclusion criteria. The mean cylindrical correction on the first postoperative day was 6.6 ± 2.3 D (range, 1.00-13.00 D). This dropped to 1.9 ± 1.7 D between 2 and 4 weeks and 1.2 ± 1.0 D (range, 0-3.25 D) by 3 months postoperatively. The mean spherical equivalent was +0.5 D on the first postoperative day and did not change significantly during the follow-up period. The mean astigmatism preoperatively (1.2 ± 0.8 D) and 3 months postoperatively (1.2 ± 1.0 D) were not statistically different (p = 0.9). There was no statistically significant change in astigmatism between 1 and 3 months and 1 and 2 years (p = 0.16, n = 33).

CONCLUSIONS

Large cylindrical refractive errors after pediatric cataract surgery through a 6.5 mm limbal incision resolve postoperatively within 3 months.

Optical characterization of Bangerter foils

PURPOSE

Optical penalization is emerging as an alternative to patching for the treatment of amblyopia. Bangerter foils offer a form of optical penalization that is distinctly different from standard techniques making use of atropine or spectacle lens manipulation, or both, to produce defocus. The authors examined the optical properties of Bangerter foils and compared them with the effect of defocus.

METHODS

Bangerter foils were evaluated on an optical bench to calculate point spread and modulation transfer functions. Retinal images through the foils were also simulated and qualitatively compared with those with defocus and Gaussian blur. Subjective visual acuity and contrast sensitivity were compared in two subjects wearing spectacles with foils and with simple defocus.

RESULTS

The optical characteristics of the Bangerter foils do not correspond well with their labeled density designation. Bangerter foils and defocus affect the modulation transfer function similarly, with more attenuation of mid-range spatial frequencies than low spatial frequencies. However, Bangerter foils do not exhibit spurious resolution and phase shifts, as does defocus.

CONCLUSIONS

The blur resulting from Bangerter filters is qualitatively different from defocus. Whether this difference is of any consequence when these two methods of optical penalization are used for amblyopia treatment remains to be investigated.

The effect of medial versus lateral rectus muscle surgery on distance-near incomitance

PURPOSE

For strabismus with distance-near incomitance (unequal distance and near deviations), it is customary to select lateral or medial rectus muscle surgery based on whether the deviation is greater at distance or near. The purpose of this study is to examine how this choice between medial and lateral rectus muscle surgery affects distance-near incomitance.

METHODS

Preoperative and postoperative distance and near deviations were obtained from a retrospective review of medical records of consecutive patients who underwent bilateral medial or lateral rectus muscle recessions or resections between January 1, 2000, and June 30, 2007.

RESULTS

A total of 626 procedures were identified. After exclusions, initial procedures included 267 medial rectus muscle recessions that produced an average of 9% more exoshift at near and 159 lateral rectus muscle recessions that produced an average of 34% more esoshift at distance. A larger preoperative distance-near incomitance is associated with a greater reduction in distance-near incomitance with surgery, irrespective of which muscles undergo surgery. Recessions for consecutive deviations and resections for residual deviations exhibited a similar pattern.

CONCLUSIONS

Esotropia tends to be greater at near and exotropia greater at distance fixation. The apparent greater effect of medial rectus muscle surgery on near deviation and lateral rectus muscle surgery on distance deviation is probably an artifact of this difference in preoperative characteristics. Whether a deviation is greater with distance or near fixation may not be a major consideration in choosing between medial or lateral rectus muscle surgery.

Late-onset Haemophilus Influenzae endophthalmitis in an immunized child after Baerveldt implant

Endophthalmitis after a glaucoma drainage implant is uncommon. In a case series of drainage implant-associated endophthalmitis, tube exposure was present in all cases.(1) Among the organisms cultured from these eyes was Haemophilus influenzae. After the introduction of the H. influenzae type b vaccine, infections related to this bacterium dramatically decreased in children. We report a case of late-onset H. influenzae endophthalmitis in an immunized child after bilateral glaucoma drainage implants without evidence of conjunctival erosion or wound dehiscence.

Effect of axial length and keratometry measurement error on intraocular lens implant power prediction formulas in pediatric patients

PURPOSE

To examine the relationship between axial length and keratometry measurement errors and intraocular lens (IOL) power calculations for pediatric eyes.

METHODS

The sensitivity of IOL power calculation to errors in axial length and keratometry measurements was computed as a function of axial length and keratometry for the SRK II, Hoffer Q, Holladay I, SRK/T, and Haigis formulas.

RESULTS

The sensitivity of the IOL power calculation to an axial length measurement error is increased at 4 to 14 D/mm error in axial length in children compared with 3 to 4 D/mm error in axial length in adults. The error in calculation is 0.8 to 1.3 D/D error in keratometry measurement for both children and adults.

CONCLUSIONS

Axial length measurement errors in pediatric eyes may lead to large errors in IOL power calculations.

Intraocular lens power calculation in children

With improving surgical technique and equipment, the acceptable age for placing an intraocular lens in infants and children is becoming younger. The tools for predicting intraocular lens power have not necessarily kept up, as current theoretical and regression intraocular lens power prediction formulas are largely based on adult eyes at axial lengths, anterior chamber depth, and keratometric values much different than those seen in infants. In addition, the adult eye has matured and is no longer growing, whereas the eyes of infants and children may continue to note changes in axial length, keratometric values, and possibly optical characteristics. Another source of error in intraocular lens power selection that is more likely to occur in pediatric patients than in adult patients is inaccuracy in measurement of axial length or keratometric power. A review of current tools and considerations for intraocular lens power prediction in infants and children is presented.

Postoperative myositis in reoperated extraocular muscles

PURPOSE

To report on a series of patients who developed orbital myositis following routine strabismus surgery.

METHODS

A retrospective medical record review of patients who developed myositis following routine strabismus surgery. Surgery was performed on all patients between 1998 and 2003 by a single pediatric ophthalmologist (SMA).

RESULTS

Four patients developed orbital myositis following routine strabismus surgery. All four cases were reoperations. Symptoms of myositis developed at a mean of 21 days after surgery (range, 4-34). In the initial patient, the diagnosis of myositis was based on clinical and computed tomography findings. The clinical course of the three subsequent patients was similar to that of the radiologically confirmed case. In all cases, the diagnosis was supported by rapid resolution after treatment with systemic corticosteroids.

CONCLUSIONS

Orbital myositis is a previously unreported complication of strabismus surgery. Reoperation appears to be a predisposing factor.

Consecutive cyclic exotropia after surgery for adult-onset cyclic esotropia

Cyclic esotropia--periods of esotropia alternating with periods of orthotropia, most commonly on a 48-hour cycle--is a rare condition seen mostly in children. Surgical correction of the maximum deviation generally corrects the esotropia without resulting in alternating periods of exotropia, as might be expected if the periodicity continued postoperatively. Unlike cyclic esotropia in children, the few reported adult cases have often been associated with severe acquired monocular visual impairment; however, the response to surgical treatment is reported to be the same as that in children. We report here an exception, in which an adult patient developed cyclic exotropia after surgical correction of her acquired cyclic esotropia.

Current concepts in the management of concomitant exodeviations

Intermittent exotropia is the most common form of divergent strabismus. Treatment is indicated with increasing tropia phase to preserve or restore binocular function and restore/reconstruct normal ocular alignment. While medical treatment is sometimes helpful for temporary relief, surgical therapy is the preferred definitive treatment modality by most pediatric ophthalmologists and strabismologists. Congenital exotropia is rare and is associated with a high incidence of amblyopia. The treatment of choice in this condition is also surgical. Sensory exotropia is most often acquired after monocular visual loss. The preferred treatment is surgical recession/resection on the impaired eye. Convergence insufficiency is usually not diagnosed until the teenage years or later, and it is best approached nonsurgically with convergence exercises. In this article, we review the current literature and practice on the diagnosis and management of exotropia with emphasis on intermittent exotropia.

Discrepancies between Intraocular Lens Implant Power Prediction Formulas in Pediatric Patients

PURPOSE

The SRK II, SRK/T, Holladay I, and Hoffer Q intraocular lens power prediction formulas have been claimed to be interchangeable in their predicted postoperative refractive outcome among pediatric patients. In this study, we evaluated this clinical perception.

DESIGN

Mathematical analysis.

METHODS

Analytical prediction of implant power using keratometry values up to 55 diopters and axial length values as short as 16 mm was performed for 2 different refractive goals using the optimized intraocular lens constants for the SRK II, SRK/T, Holladay I, Hoffer Q, and Haigis formulas. Comparison graphs for the predicted implant power of each formula were constructed and differences between predicted results of the formulas were plotted.

MAIN OUTCOME MEASURE

Predicted implant power.

RESULTS

Significant differences in intraocular lens power prediction were found among the Hoffer Q, Holladay I, and SRK II formulas in the pediatric range of axial length and keratometry values. The Holladay I and Haigis formulas were found to be similar in their intraocular lens power prediction. The SRK/T was comparable with the Holladay I and Haigis formulas, but still differed in the high keratometry values.

CONCLUSIONS

This analysis demonstrates differences in the intraocular lens power prediction among commonly used formulas for axial length and keratometry values in the pediatric range. It is unclear under what circumstances each of these formulas may be preferred in the pediatric population.

Monocular diplopia due to spherocylindrical refractive errors (an American Ophthalmological Society thesis)

PURPOSE

Ordinary spherocylindrical refractive errors have been recognized as a cause of monocular diplopia for over a century, yet explanation of this phenomenon using geometrical optics has remained problematic. This study tests the hypothesis that the diffraction theory treatment of refractive errors will provide a more satisfactory explanation of monocular diplopia.

METHODS

Diffraction theory calculations were carried out for modulation transfer functions, point spread functions, and line spread functions under conditions of defocus, astigmatism, and mixed spherocylindrical refractive errors. Defocused photographs of inked and projected black lines were made to demonstrate the predicted consequences of the theoretical calculations.

RESULTS

For certain amounts of defocus, line spread functions resulting from spherical defocus are predicted to have a bimodal intensity distribution that could provide the basis for diplopia with line targets. Multimodal intensity distributions are predicted in point spread functions and provide a basis for diplopia or polyopia of point targets under conditions of astigmatism. The predicted doubling effect is evident in defocused photographs of black lines, but the effect is not as robust as the subjective experience of monocular diplopia.

CONCLUSIONS

Monocular diplopia due to ordinary refractive errors can be predicted from diffraction theory. Higher-order aberrations--such as spherical aberration--are not necessary but may, under some circumstances, enhance the features of monocular diplopia. The physical basis for monocular diplopia is relatively subtle, and enhancement by neural processing is probably needed to account for the robustness of the percept.

Social and emotional impact of strabismus surgery on quality of life in children

PURPOSE

Improved quality of life after strabismus surgery has been demonstrated in adults, but has not been extensively studied in children. The purpose of this study was to evaluate the psychosocial effects of childhood strabismus surgery.

METHODS

This was a prospective interventional study. A modified version of the RAND Health Insurance Study quality of life instrument was administered to parents or guardians of children with strabismus. The questionnaire was administered by telephone interviews conducted by trained staff before and 2 months after corrective surgery.

RESULTS

Ninety-eight children with a mean age of 4.5 (+/-3.3) years were studied. Reliability measures (Cronbach's alpha coefficients) indicate that the questionnaire has good internal consistency (alpha > 0.7 in most subscales). Compared with before surgery, significant improvements were noted after surgery, especially within the functional limitations (paired Student's t -test, P = 0.01), social relations ( P < 0.01), general health perceptions ( P < 0.01), and developmental satisfaction ( P < 0.01) subscales.

CONCLUSIONS

Parental proxies can provide meaningful measures of children's response to strabismus surgery. Statistically significant improvements were observed in social, emotional, and functional measures of the children's health status. As previously documented for adults, this study shows that psychosocial benefits afforded by strabismus surgery also contribute to an improvement in quality of life for children.

Bilateral medial rectus muscle recession for divergence insufficiency pattern esotropia

PURPOSE

We have identified a group of mostly elderly patients characterized by chronic, slowly progressive esotropia with diplopia at distance. This study was undertaken to analyze the outcomes after bilateral medial rectus muscle recessions in this group of patients with a divergence insufficiency pattern of esotropia.

MATERIALS AND METHODS

This is a retrospective consecutive case series of eight patients treated for divergence insufficiency pattern esotropia with bilateral medial rectus muscle recessions.

RESULTS

Age at presentation was 44 to 77 years (mean age, 60) and symptoms of diplopia at distance had been present between 3 and 30 years (mean, 12.6). Six patients had been managed with progressively larger amounts of base-out (BO) prism in their distance correction over an average of 12.5 years. Each patient had a manifest esotropia at distance and smaller or no deviation at near. The mean preoperative esodeviation was 20.4 prism diopters (range, 12 to 35) at distance and 5.4 PD (range, 0 to 18) at near with a mean distance-near difference of 15.0 PD. Bilateral medial rectus muscle recession of 3.0 to 4.25 mm (mean 3.5) was performed on each patient. The mean postoperative esodeviation at distance was 3.4 PD (range 0 to 10) and the mean near deviation was 1.8 PD exophoria (range, 8 PD exophoria to 10 PD esotropia) with a mean distance-near difference of 5.1 PD. Three patients still required some prism in their spectacles for the relief of diplopia postoperatively (2 BO, 8 BO, 10 BO). The mean follow-up period was 8.5 months (range, 6 weeks to 46 months).

CONCLUSIONS

Bilateral medial rectus muscle recession is an effective treatment for slowly progressive divergence insufficiency pattern esotropia in elderly patients. The reduction in the difference between the distance and near magnitudes of esodeviation afforded by this treatment suggests that a subtle loss of medial rectus muscle elasticity is the etiology.

Horizontal versus vertical dark-adapted pupil diameters in normal individuals

PURPOSE

To determine the distribution of the difference between the horizontal and vertical dark-adapted entrance pupil diameters (PDs) in normal individuals.

SETTING

Texas Tech University Health Sciences Center, Lubbock, Texas, USA.

METHODS

In this observational cohort study, high-magnification infrared pupil photography was performed of the right eye of 26 normal volunteers from 20 to 47 years of age. The horizontal and vertical PDs were measured using commercially available digital-image software, taking into account the effect of photographic parallax.

RESULTS

In 24 subjects (85%), the vertical PD was larger than the horizontal PD; in 8 subjects (31%), it was 0.30 mm to 0.50 mm larger. In 2 subjects, the horizontal diameter was slightly larger but the difference was <0.10 mm. The mean horizontal to vertical PD ratio was 0.97.

CONCLUSIONS

In this study population, the vertical PD was larger than the horizontal PD in most subjects. Although the difference was a fraction of the total PD, it may be important for laser refractive surgery planning and preoperative risk counseling of some patients.

Microcephaly, jejunal atresia, aberrant right bronchus, ocular anomalies, and XY sex reversal

We present a patient with microcephaly, jejunal atresia, aberrant right tracheobronchial tree, mild left blepharoptosis, and corectopia (irregular pupil), left sectoral iris stromal hypoplasia and peripheral anterior synechia, and 46,XY sex reversal. Testosterone and dihydrotestosterone (DHT) levels were within normal limits for a male infant at 3 weeks of age. Gonadectomy at age 18 months revealed immature testis tissue and no evidence of Müllerian structures. PCR amplification of the androgen receptor (AR) gene and flanking genomic regions revealed no evidence for deletion. Array-comparative genomic hybridization (array-CGH) for assessment of gene dosage in other regions of the genome was normal. This patient represents a multiple anomaly disorder similar to intestinal atresia-ocular anomalies-microcephaly syndrome (MIM#243605) but incorporating 46,XY sex reversal with testicular tissue, demonstrating a defect in the sexual differentiation pathway.

Vertical rectus muscle surgery for nystagmus patients with vertical abnormal head posture

PURPOSE

To characterize the results of vertical rectus muscle recession, or recession and resection surgery for vertical abnormal head posture (VAHP) due to null-point nystagmus.

METHOD

This is a retrospective, noncomparative, consecutive case series of patients who underwent vertical rectus muscle recession alone, recession then resection, or combined recession/resection surgery for VAHP due to null-point nystagmus. The primary outcome measure was the amount of residual VAHP.

RESULTS

Twenty patients with VAHP due to null-point nystagmus were studied. The mean follow-up interval after surgery was 49 months (median: 44 months; range 9 to 124 months). Preoperative VAHP ranged from 10 degrees to 45 degrees, and the total amount of bilateral vertical rectus muscle recession, or recession and resection surgery, ranged from 8.5 to 20.0 mm per eye. After recession alone, 5/11 had residual VAHP < or = 5 degrees. The remaining six underwent subsequent resection or plication for residual VAHP > 10 degrees that resulted in residual VAHP < or = 5 degrees in each case. After combined recession/resection, 6/9 had residual VAHP < or = 5 degrees and the remaining three had VAHP < 10 degrees.

CONCLUSION

Large amounts of vertical rectus muscle surgery are indicated to successfully correct the VAHP associated with nystagmus with a vertical null point. Combined recession/resection of the appropriate vertical rectus muscles, instead of recession alone, appears to be a more effective procedure.

Assessing the need for posterior sclerotomy at the time of filtering surgery in patients with Sturge-Weber syndrome

PURPOSE

Posterior sclerotomy has been recommended for prevention of intraoperative choroidal hemorrhages and choroidal effusions in patients with Sturge-Weber syndrome (SWS) or Klippel-Trenaunay-Weber (KTW) syndrome undergoing glaucoma filtering surgery. In this study, we evaluated this unproven clinical perception.

DESIGN

A retrospective, noncomparative, case series.

PARTICIPANTS

Seventeen consecutive patients with SWS or KTW syndrome who underwent glaucoma filtering surgery without prophylactic posterior sclerotomy or other prophylactic measures between January 1973 and March 1997 at a university-based practice.

INTERVENTION

Glaucoma filtering surgery without prophylactic posterior sclerotomy.

MAIN OUTCOME MEASURES

Incidence of intraoperative and postoperative choroidal effusion, choroidal detachment, or choroidal hemorrhage.

RESULTS

No intraoperative choroidal effusion, choroidal detachment, or choroidal hemorrhage occurred in this series. After surgery, 6 patients had a transient choroidal effusion. Surgical drainage was not required in any of them. No suprachoroidal hemorrhages occurred after surgery.

CONCLUSIONS

We did not encounter significant intraoperative suprachoroidal hemorrhage, choroidal effusions, or a combination requiring therapeutic intervention in our series. This finding leads us to question the necessity for prophylactic posterior sclerotomy to prevent the occurrence of these complications in patients with SWS and KTW syndrome undergoing glaucoma filtering surgery.

Infantile spasms as a cause of acquired perinatal visual loss

BACKGROUND

Visual abnormalities have been described in patients with infantile spasms (IS), an epileptic syndrome of early childhood.

METHODS

We report on 3 children who exhibited cortically mediated visual regression in association with the development of IS.

RESULTS

In 1 patient, loss of visual behavior was the presenting complaint. In all patients, visual behavior improved with treatment of seizures.

CONCLUSIONS

IS are a potentially treatable cause of cortically impaired vision in early childhood. Because visual behavior might improve when the seizures are treated, patients should be referred appropriately.