A Comparison of Examination Equipment Used During Common Clinical Ophthalmologic Tasks

Background

Ophthalmologists report a high prevalence of work-related musculoskeletal symptoms, particularly of the neck and shoulders. Improving the design of equipment used in the clinical environment may reduce exposures to physical risk factors (e.g., sustained muscular exertions and non-neutral postures) associated with neck and shoulder pain among ophthalmologists.

Purpose

To compare estimates of neck and shoulder muscle activity and upper arm posture during use of conventional and alternative examination equipment common in clinical ophthalmologic practice.

Methods

Fifteen ophthalmologists performed one mock clinical examination using conventional equipment and one mock clinical examination using alternative equipment with the potential to reduce exposure to sustained muscular exertions and non-neutral upper arm postures. The alternative equipment included a slit-lamp biomicroscope with inclined viewing oculars, adjustable elbow supports, and a wider table-top with more room for supporting the arms in comparison to the conventional slit-lamp biomicroscope. A wireless binocular indirect ophthalmoscope was also evaluated that had a more even weight distribution than the conventional design. Measurements of upper trapezius and anterior deltoid muscle activity, upper arm posture, and perceived usability were used to compare the conventional and alternative equipment.

Results

In comparison to the conventional slit lamp biomicroscope, the alternative slit lamp biomicroscope led to (i) 12% to 13% reductions in upper trapezius muscle activity levels, (ii) a 9% reduction in left anterior deltoid muscle activity levels, and (iii) a 15% reduction in the percentage of work time spent with the left upper arm elevated in positions greater than 60°. In addition, participants rated the comfort and adjustability of both the alternative slit lamp biomicroscope and binocular indirect ophthalmoscope more favorably than the conventional equipment.

Conclusions

The results suggest that the alternative slit-lamp biomicroscope may help to reduce overall muscular demands and non-neutral postures of the neck and shoulder region among ophthalmologists.

Confirmation of the association between the TCF4 risk allele and Fuchs endothelial corneal dystrophy in patients from the Midwestern United States

PURPOSE

To determine the role of the single nucleotide polymorphism (SNP) (rs613872) in the TCF4 gene in Fuchs endothelial corneal dystrophy (FECD) in patients from Iowa.

METHODS

A cohort of 82 patients with FECD and 163 normal control subjects from Iowa were genotyped at the SNP rs613872 using a real-time allelic discrimination assay.

RESULTS

The frequencies of the alleles of rs613872 were compared between FECD patients and control subjects. A highly significant association (p-value = 2.96 × 10(-10)) was detected between this SNP and FECD. Comparison of the genotypes of SNP rs613872 between FECD patients and control subjects produced a p-value of 2.43 × 10(-10).

CONCLUSION

Prior reports have shown that SNP rs613872 in the TCF4 gene is highly associated with FECD. Our study confirms this association and shows that the TCF4 gene has an important role in the pathogenesis of corneal disease in patients from Iowa.

A survey study of musculoskeletal disorders among eye care physicians compared with family medicine physicians

PURPOSE

To evaluate the prevalence of musculoskeletal disorders among eye care physicians compared with family medicine physicians.

DESIGN

Case control study.

PARTICIPANTS AND CONTROLS

Ophthalmologists and optometrists at the University of Iowa and Mayo Clinic (participants) and family medicine physicians at the University of Iowa and Mayo Clinic (controls).

METHODS

An electronic survey was e-mailed to all subjects.

MAIN OUTCOME MEASURES

The prevalence of musculoskeletal symptoms between eye care providers and family medicine physicians (control group).

RESULTS

One hundred eight-six surveys were completed by 94 eye care physicians and 92 family medicine physicians with a response rate of 99% and 80%, respectively. There were no significant differences between the 2 groups with regard to mean age, gender, body mass index, years with current employer, or years in practice. Eye care providers, compared with their family medicine colleagues, reported a higher prevalence of neck (46% vs 21%; P<0.01), hand/wrist pain (17% vs 7%; P = 0.03), and lower back pain (26% vs 9%; P<0.01). A greater proportion of eye care physicians classified their job as a high-strain job (high demand, low control; 31% vs 20%) and a lower proportion classified their job as an active job (high demand, high control; 24% vs 47%; p = 0.01). Several job factors reported by eye care providers to contribute to musculoskeletal symptoms included performing the same task repeatedly, working in awkward/cramped positions, working in the same position for long periods, and bending/twisting the back (all P<0.01).

CONCLUSIONS

In this survey, the study group, composed of ophthalmologists and optometrists, had a higher prevalence of neck, hand/wrist, and lower back pain compared with family medicine physicians; repetitive tasks, prolonged or awkward/cramped positions, and bending/twisting were contributory factors. Given the ramifications of these findings, future efforts should concentrate on modifications to the eye care providers' work environment to prevent or alleviate musculoskeletal disorders and their personal and socioeconomic burden.

Donor-related Candida keratitis after Descemet stripping automated endothelial keratoplasty

PURPOSE

To report 2 cases of donor-to-host transmission of Candida albicans interface keratitis after Descemet stripping automated endothelial keratoplasty (DSAEK).

METHODS

We performed clinical and microbiologic examinations on 2 patients who underwent DSAEK for pseudophakic corneal edema.

RESULTS

Two patients underwent uneventful DSAEK surgery using corneal tissue from the same donor. The donor corneoscleral rims were cultured at the time of surgery and both rims subsequently grew C. albicans and Candida glabrata. Approximately 5 weeks after surgery, infiltrates were noted in the DSAEK interface in both of these patients. Despite treatment with antifungal therapy, the Candida keratitis was unable to be controlled medically and required surgical intervention in each case, after which there was no recurrence of infection.

CONCLUSIONS

Candida interface keratitis can occur after DSAEK. These 2 cases emphasize the importance of donor corneoscleral rim cultures, especially with the increase in lamellar and endothelial keratoplasty, which can make such interface infections more difficult to diagnose and treat. Patients with fungal positive donor corneal rim cultures should be prophylactically treated with antifungal therapy.

Short-Term Motor and Sensory Outcomes in Acquired Nonaccommodative Esotropia of Childhood

Information on the management of acquired nonaccommodative esotropia (ANAET) of childhood is incomplete. Most prior reports combine the results of patients with both accommodative and nonaccommodative esodeviations. The primary objective of this study was to describe the early postoperative motor and sensory results of children with acquired nonaccommodative esotropia. The medical records of 72 consecutive children with ANAET who underwent surgical correction at East Tennessee State University College of Medicine from August 1, 1995 through October 1, 2001 were retrospectively reviewed. The median age at surgery for the 72 study patients was 43.8 months with a median angle of deviation of 30 prism diopters (PD) at both distance and near. Ten patients (13.9%) required a second surgical procedure while one patient (1.4%) required a third. The cumulative probability of a second surgery within two years of the first procedure was 24% (95% CI 4-43%). During a median postoperative follow-up period of 7.1 months, 64 (88.9%) patients were within 8 PD of orthotropia on the last postoperative examination. Normal postoperative stereoacuity was achieved in several children whose deviation began after 30 months of age, as well as in one child who was misaligned for at least two years prior to surgery. Although the postoperative follow-up on these patients with acquired nonaccommodative esotropia managed without prism adaptation is short, the motor results are similar to other studies on patients with acquired esotropia, with sensory outcomes superior to those obtained in children with congenital esotropia.

Keratoplasty for treatment of Acanthamoeba keratitis

PURPOSE

To evaluate and compare the outcomes of therapeutic keratoplasty (TKP) and optical keratoplasty (OKP) in the management of medically unresponsive Acanthamoeba keratitis and post-keratitis scarring, respectively.

DESIGN

Retrospective, nonrandomized, comparative, interventional case series.

PARTICIPANTS

Thirty patients with Acanthamoeba keratitis treated at a single center.

METHODS

Retrospective review of all cases of penetrating keratoplasty (PKP) or lamellar keratoplasty (LKP) performed for Acanthamoeba keratitis at a single center between January 1, 1980, and December 31, 2007. Inclusion criteria included histopathologic confirmation of Acanthamoeba organisms in the surgical specimen and at least 6 months of postoperative follow-up.

MAIN OUTCOME MEASURES

Postoperative complications, microbiological cure, graft survival, and visual acuity.

RESULTS

Thirty-one eyes of 30 patients met the inclusion criteria. This included 22 eyes (22 patients) that were initially treated with TKP (20 PKP/2 LKP) and 9 eyes (8 patients) treated with OKP (8 OKP/1 LKP). Of the 22 eyes treated with TKP, multiple keratoplasties (range, 2-6) were performed in 12 eyes (55%), whereas repeat keratoplasty was performed in only 1 eye (11%) treated with OKP (P = 0.004). Recurrent Acanthamoeba keratitis, glaucoma, early and late persistent epithelial defects, and endophthalmitis were more likely to occur after TKP than after OKP. A microbiological cure was achieved in all surgical cases. Among eyes treated with TKP, this required 1 keratoplasty in 14 eyes, 2 keratoplasties in 6 eyes, and 3 keratoplasties in 2 eyes. After the initial keratoplasty, Kaplan-Meier survivals after TKP were 45.5%, 45.5%, and 37.5% at 1 year, 5 years, and 10 years, respectively, compared with 100%, 100%, and 66.7%, respectively, after OKP (P = 0.004). The median visual acuity was 20/40 after TKP and 20/25 after OKP. Eyes treated with TKP were less likely to obtain visual acuity of 20/40 or better and more likely to have vision of 20/200 or worse.

CONCLUSIONS

Therapeutic keratoplasty can successfully treat medically unresponsive cases of Acanthamoeba keratitis, although multiple grafts may be required and the visual prognosis is guarded. Optical keratoplasty performed after resolution of active keratitis is associated with an excellent prognosis for both graft survival and visual outcome.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Histologic findings in T-cell lymphoma infiltration of the optic nerve

OBJECTIVE

To report the clinical and histologic features of lymphomatous infiltration of the optic nerve by systemic T-cell non-Hodgkin's lymphoma (NHL).

DESIGN

Interventional case report.

PARTICIPANT

A patient with peripheral T-cell NHL.

METHODS

A 39-year-old man with a diagnosis of peripheral T-cell NHL, stage IV, with CNS involvement and decreased vision was found to have lymphomatous infiltration of the optic nerves.

MAIN OUTCOME MEASURE

Visual acuity.

RESULTS

Despite treatment with chemotherapy and an optic nerve sheath fenestration, the patient lost vision in the right eye and subsequently underwent an optic nerve biopsy. The histopathology showed diffuse infiltration with a clonal population of lymphocytic cells that were CD3 positive and CD20 negative, consistent with T-cell NHL.

CONCLUSION

Optic nerve infiltration from systemic B-cell lymphoma is rare and has been reported; we report an unusual case of bilateral optic nerve infiltration secondary to peripheral T-cell NHL.

Intraocular use of rituximab

PURPOSE

To evaluate the toxicity of 1 mg of intraocular rituximab and to present a small case-series of patients treated with intravitreal rituximab.

METHODS

Rituximab (1 mg/0.1 ml) was injected in the vitreous of one eye of three Dutch-belted rabbits. Two animals were injected with balanced salt solution as controls. At 1 month the rabbits were killed and the eyes examined by light microscopy. Three patients (five eyes) with intraocular lymphoma were also treated with a 1 mg injection of rituximab.

RESULTS

The treated rabbit eyes and the control eyes showed no light microscopic evidence of ocular toxicity at 1 month following injection. The five human eyes of three patients have shown no evidence of intraocular toxicity with a median follow-up time of 3.6 months (range 2.0-6.4 months). One patient received a total of four injections in the right eye and three injections in the left eye.

CONCLUSION

Intravitreal rituximab at a dose of 1 mg does not appear to cause toxicity in rabbit eyes and in the five eyes of three patients.

Confocal microscopy of a femtosecond laser LASIK flap before separation

PURPOSE

To describe stromal changes after a femtosecond laser laser-assisted in situ keratomileusis (LASIK) flap was created but not separated.

DESIGN

Case report.

METHODS

As part of a randomized paired-eye study comparing LASIK flap creation by a femtosecond laser to a mechanical microkeratome, a femtosecond laser flap was successfully created on one eye of one patient, but the flap was not separated because of a flap-related complication in the fellow eye. Confocal microscopy of the femtosecond laser flap was performed before and at intervals after it was created.

RESULTS

Activated keratocytes and interface haze were visible at one day after femtosecond laser treatment, with gradual resolution toward normal over two months. The femtosecond laser flap was easily separated four months after it was created.

CONCLUSIONS

Corneal photodisruption by the femtosecond laser is associated with transient keratocyte activation and corneal haze, but marked wound healing does not occur to hinder flap separation several months later.

Retinal pigment epithelial tear after intravitreal ranibizumab

PURPOSE

To report two cases of a retinal pigment epithelial (RPE) tear after intravitreal injection of 0.05 mg ranibizumab.

DESIGN

Observational case report.

METHODS

Two patients with choroidal neovascularization (CNV) resulting from age-related macular degeneration (AMD) were treated with an intravitreal injection of ranibizumab.

RESULTS

Both patients were found to have a RPE tear on follow-up visits at one month, confirmed by optical coherence tomography (OCT) and by fluorescein or indocyanine green angiography.

CONCLUSIONS

RPE tears may occur after intravitreal injection of ranibizumab. Further study is needed to determine whether CNV membranes associated with pigment epithelial detachments (PED) are more likely to develop RPE tears after treatment with anti-vascular endothelial growth factor (anti-VEGF) agents.

A splice-site mutation in CCM1/KRIT1 is associated with retinal and cerebral cavernous hemangioma

PURPOSE

To report a case of a unilateral retinal cavernous hemangioma associated with a novel splice-site mutation in CCM1/KRIT1.

METHODS

An 11-year-old girl was noted to have an asymptomatic retinal cavernous hemangioma in the left eye. CCM1/KRIT1 was screened for mutations.

RESULTS

Genetic evaluation of CCM1/KRIT1 revealed a single guanine-to-cytosine transversion in the invariant splice acceptor consensus sequence of intron 8 (c.1146-1G-->C), which is predicted to result in abnormal protein splicing.

CONCLUSIONS

Mutations in CCM1/KRIT1 may be found in asymptomatic patients with retinal cavernous hemangioma.

Comparison of Corneal Endothelial Cell Images From a Noncontact Specular Microscope and a Scanning Confocal Microscope

PURPOSE

We compared endothelial cell density (ECD) from images recorded by the ConfoScan 3 confocal microscope and a noncontact specular microscope.

METHODS

Endothelial micrographs of 50 normal corneas of 25 subjects were acquired by a Konan Noncon Robo noncontact specular microscope (Konan Medical, Inc., Hyogo, Japan) and a ConfoScan 3 confocal microscope (Nidek Technologies, Inc, Greensboro, NC). ECD was determined in images from both instruments by using the HAI CAS System Corners Method (HAI Labs, Inc., Lexington, MA). Distances in the images from both machines were calibrated from images of an external scale. Images from the ConfoScan 3 were also assessed using the automated endothelial analysis software provided by the manufacturer, with and without manual correction.

RESULTS

The ECD was 2634 +/- 186 cells/mm(2) (mean +/- SD) and 2664 +/- 173 cells/mm(2) by the Robo and ConfoScan 3 Corners methods, respectively. Differences between these 2 methods were not significant. When the automated analysis software was used, however, significant differences were found (P = 0.001). The uncorrected analysis program provided with the ConfoScan 3 indicated a higher ECD (2742 +/- 284 cells/mm(3)) than the Corners method did with images from the Robo and ConfoScan 3. The ECD from the manually corrected ConfoScan 3 method was 2716 +/- 229 cells/mm(3), not significantly different from the ConfoScan 3 Corners method but significantly different from the Robo Corners method.

CONCLUSIONS

The ConfoScan 3 can be used interchangeably with the Robo when the Corners method is used to assess ECD and the magnification of both microscopes is calibrated with an external scale. If the proprietary software provided with the ConfoScan 3 is used, it should be manually corrected.

Keratocyte Density

PURPOSE

The ConfoScan 3 clinical confocal microscope provides sharper images of cells in the stroma than the Tandem Scanning confocal microscope does. In this study, we compared volumetric densities of stromal cells determined from images recorded by these two instruments.

METHODS

Fifty corneas of 25 normal subjects were examined by confocal microscopy, first by using a Tandem Scanning confocal microscope and then by using a ConfoScan 3 confocal microscope. Bright objects, assumed to represent keratocytes, were counted in a known area of two frames selected from the mid-stroma. The effective depth of the sample volume represented by each frame was estimated from the number of consecutive frames and the corresponding distance that selected cells were visible and countable during a scan. Density was the number of visible cells in the sample area divided by the effective sample volume.

RESULTS

The effective focal depth of the Tandem Scanning microscope was 11.9 +/- 2.6 microm (mean +/- SD), and was 25.9 +/- 7.1 microm for the ConfoScan 3. Mean cell density at mid stroma was 23,013 +/- 4,420 cells/mm(3) with the Tandem Scanning microscope and 23,996 +/- 2,898 cells/mm(3) with the ConfoScan 3. This difference was not significant (P = 0.15).

CONCLUSIONS

In normal corneas, the ConfoScan 3 and the Tandem Scanning confocal microscopes indicate stromal cell densities that are not significantly different from each other. Estimates of cell density from both instruments require an accurate estimate of the effective depth of the sample volume; this depth is approximately 2.2 times greater with the ConfoScan 3. This difference must be considered when comparing results from studies that use one instrument with results from studies that use the other.

Progressive increase in the angle of deviation in acquired nonaccommodative esotropia of childhood

PURPOSE

Although the angle of deviation in patients with congenital esotropia has been shown to increase during the early preoperative period, few data exist regarding this change in other forms of childhood esotropia. The primary objective of this study was to investigate whether the angle of deviation increases with time in patients with acquired nonaccommodative esotropia (ANAET).

METHODS

The medical records of all children whose ANAET was diagnosed at East Tennessee State University College of Medicine from August 1, 1995, through October 1, 2001, were retrospectively reviewed. All patients were assessed for any change in the amount of their strabismic angle and associated risk factors.

RESULTS

Eighty-two patients with ANAET were identified, and all except 3 underwent more than one examination. Of the 79 children who underwent more than one examination, 26 (32.9%) displayed an angle increase of > or =10 prism diopters (PD) during a median follow-up period of 2.9 months. The ANAET of those patients whose angle increased by > or =10 PD was diagnosed (28.4 months of age vs 45.5 months of age, P =.003), and they underwent surgery (35.9 months of age vs 53.3 months of age, P =.003) at a significantly younger median age than those whose angle increased <10 PD.

CONCLUSIONS

The angle of deviation of approximately one third of patients with ANAET in this study increased at least 10 PD in the early preoperative period. This increase occurs more often in younger patients and underscores the importance of performing serial measurements of the deviating angle before surgical intervention is undertaken.

Clinicopathologic correlations in 646 consecutive surgical eye specimens, 1990-2000

All surgical eye specimens examined in our pathology laboratory between January 1, 1990, and July 31, 2000 (N = 646), were classified by surgical procedure (enucleation, evisceration, or exenteration) and pathologic diagnosis. Among 523 enucleated globes (81.0%), 252 (48.2%) contained tumors, of which 208 were intraocular malignant melanomas. Nonneoplastic causes for enucleation included glaucoma (67/523 [12.8%]), phthisis bulbi (61/523 [11.7%]), and recent trauma (59/523 [11.3%]). Sixty-seven specimens (10.4%) had been eviscerated. Fifty-six specimens (8.7%) were obtained by exenteration performed to manage malignant tumors originating in or invading the orbit. Between 1990 and 2000, the percentage of procedures performed to remove neoplasms decreased from 65% to 38%, procedures performed to treat glaucoma increased from 4% to 29%, and those to treat phthisis bulbi increased from 8% to 13%. The numbers of procedures remained relatively constant for trauma and for infectious and inflammatory diseases.