Bone marrow transplantation and cataract development

Non-GVHD ocular complications after hematopoietic cell transplantation: expert review from the Late Effects and Quality of Life Working Committee of the CIBMTR and Transplant Complications Working Party of the EBMT

Non-graft-versus-host disease (non-GVHD) ocular complications are generally uncommon after hematopoietic cell transplantation (HCT), but can cause prolonged morbidity affecting activities of daily living and quality of life. Here we provide an expert review of non-GVHD ocular complications in a collaboration between transplant physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Complications discussed in this review include cataracts, glaucoma, ocular infections, ocular involvement with malignancy, ischemic microvascular retinopathy, central retinal vein occlusion, retinal hemorrhage, retinal detachment and ocular toxicities associated with medications. We have summarized incidence, risk factors, screening, prevention and treatment of individual complications and generated evidence-based recommendations. Baseline ocular evaluation before HCT should be considered in all patients who undergo HCT. Follow-up evaluations should be considered according to clinical symptoms, signs and risk factors. Better preventive strategies and treatments remain to be investigated for individual ocular complications after HCT. Both transplant physicians and ophthalmologists should be knowledgeable of non-GVHD ocular complications and provide comprehensive collaborative team care.

Non-Graft-versus-Host Disease Ocular Complications after Hematopoietic Cell Transplantation: Expert Review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society for Blood and Marrow Transplantation

Non-graft-versus-host disease (GVHD) ocular complications are generally uncommon after hematopoietic cell transplantation (HCT) but can cause prolonged morbidity affecting activities of daily living and quality of life. Here we provide an expert review of non-GVHD ocular complications in a collaboration between transplantation physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Complications discussed in this review include cataracts, glaucoma, ocular infections, ocular involvement with malignancy, ischemic microvascular retinopathy, central retinal vein occlusion, retinal hemorrhage, retinal detachment and ocular toxicities associated with medications. We summarize the incidence, risk factors, screening, prevention, and treatment of individual complications and generate evidence-based recommendations. Baseline ocular evaluation before HCT should be considered in all patients who undergo HCT. Follow-up evaluations should be considered according to clinical signs and symptoms and risk factors. Better preventive strategies and treatments remain to be investigated for individual ocular complications after HCT. Both transplantation physicians and ophthalmologists should be knowledgeable about non-GVHD ocular complications and provide comprehensive collaborative team care.

Cataract after allogeneic hematopoietic stem cell transplantation in childhood

AIM

The aim of this study was to study long-term visual outcome and cataract development in children and adolescents after hematopoietic stem cell transplantation (HSCT) in childhood.

METHODS

Best corrected visual acuity (BCVA), refraction and lens status were examined in a prospective study of 139 children and adolescents.

RESULTS

In total, 139 patients (58 female), median age 6.6 years at HSCT (range 0.4-17.5 years), were followed up for a median of 8.0 years (1-19.4 years). Median BCVA in the better eye was 1.0 decimal. Altogether 19 of 131 patients developed cataract requiring surgery, while 46 developed less prominent lens opacities and 66 had clear lenses at time of latest follow-up. Patients conditioned with total body irradiation had a higher risk of developing lens opacities or cataract (p < 0.0001) as did patients with malignant disease, irrespective of irradiation treatment (p < 0.0001). Cumulative analysis showed that 50% of all patients had developed lens opacities/cataract after 10.2 years. Patients who ultimately needed cataract surgery developed cataract earlier than others (p = 0.006).

CONCLUSION

Lens opacities or cataract were more common in children or adolescents with malignant disease and after conditioning with irradiation. Regular ophthalmological follow-up is important after HSCT for early intervention to avoid amblyopia.

Outcomes of cataract surgery in graft-versus-host disease

PURPOSE

To study the outcomes of cataract surgery in patients with graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

Retrospective review of 72 eyes of 41 patients (age, 17-69 years at the time of surgery) with chronic GVHD after HSCT, who underwent cataract surgery between 2008 and 2012 at the Department of Ophthalmology and Visual Sciences, W. K. Kellogg Eye Center, University of Michigan. Ophthalmic data collected included best-corrected visual acuity (BCVA), responses to Ocular Surface Disease Index (OSDI) questionnaire, dry eye severity, and postoperative complications.

RESULTS

BCVA improved from 20/49 to 20/25 (P < 0.0001) after surgery. Eight patients (20%) had pretransplantation total body irradiation and 39 patients (95%) received systemic corticosteroids for the treatment of GVHD. Postoperative complications included cystoid macular edema (4 eyes), corneal ulceration with perforation (2 eyes: 1 infected and 1 sterile), and band keratopathy (1 eye). After surgery, subjective OSDI responses and dry eye disease (DED) did not change significantly from before cataract surgery, although OSDI showed a trend toward worsening.

CONCLUSIONS

With careful monitoring and management of DED and concurrent ocular surface disease, cataract surgery generally has good visual outcomes in patients with GVHD. However, aggravation of the preexisting ocular surface disease is frequent, and despite meticulous postoperative maintenance therapy, vision-threatening complications may occur.

Outcomes of phacoemulsification in patients with chronic ocular graft-versus-host disease

PURPOSE

The purpose of this study was to evaluate the outcomes of phacoemulsification in patients with ocular graft-versus-host disease (GVHD).

METHODS

The occurrence of cataracts, cataract surgery, and its outcomes were analyzed in the medical records of 229 patients (458 eyes) with ocular GVHD. Outcome measures included pre- and postoperative corrected distance visual acuity (CDVA) and the rate of postoperative complications.

RESULTS

Of the 458 eyes evaluated, 58 were pseudophakic; from the 400 phakic eyes, 238 (59 %) presented with cataracts and 62 (26 %) underwent cataract surgery. Analysis of postoperative complications and visual outcomes at 1 month was performed in 51 eyes in which detailed surgical and immediate postoperative records were available. Preoperatively, the mean CDVA was 0.67 ± 0.57 LogMAR (Snellen 20/93), improving postoperatively to 0.17 ± 0.18 (Snellen 20/29) at 1 month (P < 0.0001), and to 0.13 ± 0.14 (Snellen 20/26) by the final follow-up visit (P < 0.0001). Postoperative complications included corneal epithelial defects (8 %), filamentary keratitis (6 %), worsening of corneal epitheliopathy (16 %), posterior capsular opacification (18 %), and cystoid macular edema (4 %). A corrected distance visual acuity of 20/30 or better was achieved in 87 % of the eyes; suboptimal CDVA improvement was attributable to severe ocular surface disease, pre-existing advanced glaucoma, and prior macular surgery.

CONCLUSIONS

Phacoemulsification in patients with chronic ocular GVHD is a safe and efficacious procedure resulting in significant visual improvement. Overall, postoperative adverse events responded well to timely management.

Dose response for radiation cataractogenesis: a meta-regression of hematopoietic stem cell transplantation regimens

PURPOSE/OBJECTIVE(S)

To perform a meta-regression on published data and to model the 5-year probability of cataract development after hematopoietic stem cell transplantation (HSCT) with and without total body irradiation (TBI).

METHODS AND MATERIALS

Eligible studies reporting cataract incidence after HSCT with TBI were identified by a PubMed search. Seventeen publications provided complete information on radiation dose schedule, fractionation, dose rate, and actuarial cataract incidence. Chemotherapy-only regimens were included as zero radiation dose regimens. Multivariate meta-regression with a weighted generalized linear model was used to model the 5-year cataract incidence and contributory factors.

RESULTS

Data from 1386 patients in 21 series were included for analysis. TBI was administered to a total dose of 0 to 15.75 Gy with single or fractionated schedules with a dose rate of 0.04 to 0.16 Gy/min. Factors significantly associated with 5-year cataract incidence were dose, dose times dose per fraction (D•dpf), pediatric versus adult status, and the absence of an ophthalmologist as an author. Dose rate, graft versus host disease, steroid use, hyperfractionation, and number of fractions were not significant. Five-fold internal cross-validation showed a model validity of 83% ± 8%. Regression diagnostics showed no evidence of lack-of-fit and no patterns in the studentized residuals. The α/β ratio from the linear quadratic model, estimated as the ratio of the coefficients for dose and D•dpf, was 0.76 Gy (95% confidence interval [CI], 0.05-1.55). The odds ratio for pediatric patients was 2.8 (95% CI, 1.7-4.6) relative to adults.

CONCLUSIONS

Dose, D•dpf, pediatric status, and regimented follow-up care by an ophthalmologist were predictive of 5-year cataract incidence after HSCT. The low α/β ratio indicates the importance of fractionation in reducing cataracts. Dose rate effects have been observed in single institution studies but not in the combined data analyzed here. Although data were limited to articles with 5-year actuarial estimates, the development of radiation-induced cataracts extends beyond this time.

Impact of ocular graft-versus-host disease on visual quality of life in patients after allogeneic stem cell transplantation: questionnaire study

PURPOSE

To determine the influence of ocular complications on quality of life (QoL) 3 years after allogeneic stem cell transplantation (allo-SCT).

METHODS

All 54 adult patients that underwent and survived allo-SCT in 2006/2007 in our centre received two questionnaires (VFQ-25: visual function questionnaire-25 and OSDI: ocular surface disease index). In addition, the following data were included: gender, age, underlying disease, presence of chronic and/or ocular graft-versus-host disease (GVHD), number of visits to an ophthalmologist, manifestations of dry eye disease, the duration of follow-up and treatment for ocular GVHD.

RESULTS

Ocular GVHD developed in 26% (14 of 54) of patients and 71% (10 of 14) received treatment for ocular GVHD. The presence of ocular GVHD correlated with the severity of systemic GVHD (correlation coefficient: 0.52, p = 0.00). The Karnofsky scores were significantly lower in the patients with ocular GVHD compared to the patients with no ocular GVHD (p = 0.001). Karnofsky scores were weakly correlated with the severity of systemic GVHD (correlation coefficient: 0.25, p = 0.03. Three years after the all-SCT, OSDI and VFQ-25 scores were significantly impaired in patients with ocular GVHD [mean: 76.5; range (46.1-100) and mean: 31.1; range (0-72.9)] compared to patients with no ocular GVHD [mean: 89.4; range (45.2-100) and mean: 12.9; range (0-58.3); p = 0.02]. The scores of the VFQ-25 were significantly lower in the domains of general health, ocular pain, social functioning and role difficulties.

CONCLUSION

The long-term vision-related QoL measured by the OSDI and VFQ-25 was impaired in patients with ocular GVHD.

Ocular manifestations of graft-versus-host disease

Allogeneic hematopoietic stem cell transplantation (HSCT) has evolved over the past two decades to become the standard of care for hematologic and lymphoid malignancies. Major ocular complications after allogeneic HSCT have been increasing in number and severity. Graft-versus-host disease (GVHD) remains a major cause of ocular morbidity after allogeneic HSCT. The main objective of this review is to elucidate the ocular complications in patients developing GVHD following HSCT. Ocular complications secondary to GVHD are common and include dry eye syndrome, acquisition of ocular allergy from donors with allergic disorders. Eyelid changes may occur in GVHD leading to scleroderma-like changes. Patients may develop poliosis, madarosis, vitiligo, lagophthalmos, and entropion. The cornea may show filamentary keratitis, superficial punctate keratitis, corneal ulcers, and peripheral corneal melting which may lead to perforation in severe cases. Scleritis may also occur which can be anterior or posterior. Keratoconjunctivis sicca appears to be the most common presentation of GVHD. The lacrimal glands may be involved with mononuclear cell infiltration of both the major and accessory lacrimal glands and decrease in tear production. Severe dry eye syndrome in patients with GVHD may develop conjunctival scarring, keratinization, and cicatrization of the conjunctiva. Therapy of GVHD includes systemic immunosuppression and local therapy. Surgical treatment in refractory cases includes surgical intervention to improve the manifestation of GVHD of the eye. This may include tarsorrhapy, prose lenses, punctal occlusions and corneal transplantation.

Visual outcome and cataract development after allogeneic stem-cell transplantation in children

PURPOSE

To report visual functions and prevalence of cataract after haematopoetic stem-cell transplantation (SCT) during childhood and to determine the impact of different conditioning regimes and other possible risk factors.

METHODS

Assessment of visual acuity (VA), slit-lamp biomicroscopy of the lenses and examination of the ocular fundii were performed in 79 subjects 2-18 years (median 7 years) after SCT.

RESULTS

Best-corrected decimal VA > or = 0.5 was achieved in 152/158 eyes (96%). There was an increased risk of cataract after conditioning with single-dose total body irradiation (s-TBI) or fractionated TBI (f-TBI) compared to busulfan or other chemotherapy (P < 0.001) and an increased risk of developing cataract earlier if treated with s-TBI compared to f-TBI (P < 0.01). The TBI mode did not affect the time to first surgical intervention. Apart from s-TBI and f-TBI, age was found to be an independent risk factor. Cataract also developed in patients prepared with chemotherapy but no patient required surgery. Neither treatment with steroids for 6 months or longer nor history of chronic graft versus host disease (GVHD) influenced cataract development.

CONCLUSION

Conditioning with full dose f-TBI compared to s-TBI postpones but does not prevent cataract or cataract surgery while chemotherapy-based conditioning induces less severe cataracts, usually not requiring surgery. Corticosteroids or GVHD do not appear as risk factors.

Ocular manifestations of graft versus host disease

PURPOSE OF REVIEW

A review of the current literature regarding the ocular manifestations and management of graft versus host disease is presented.

RECENT FINDINGS

A variety of systemic and topical anti-inflammatory or immunomodulatory agents, including prednisolone acetate, cyclosporine A, FK506, autologous serum, and retinoic acid show promise in controlling ocular graft versus host disease.

SUMMARY

Graft versus host disease is a common manifestation of allogeneic stem cell transplantation. Ocular manifestations are found in a majority of patients and may be the presenting symptom. Ocular findings include keratoconjunctivitis sicca, pseudomembranous conjunctivitis, corneal ulceration and perforation, and microvascular retinopathy. Systemic and local therapy may be used to control ocular disease.

Stem cell transplantation: supportive care and long-term complications

With increasing hematopoietic stem cell transplant (HSCT) activity and improvement in outcomes, there are many thousands of HSCT survivors currently being followed by non-transplant clinicians for their healthcare. Several types of late sequelae from HSCT have been noted, and awareness of these complications is important in minimizing late morbidity and mortality. Late effects can include toxicities from the treatment regimen, infections from immunodeficiency, endocrine disturbances, growth impairment, psychosocial adjustment disorders, second malignancies, and chronic graft-versus-host disease (GVHD). A variety of risk factors for these complications have been noted. The clinician should be alert to the potential for these health issues. Preventive and treatment strategies can minimize morbidity from these problems and optimize outcomes.

Phacoemulsification in patients after allogeneic bone marrow transplantation

OBJECTIVE

To study the outcomes of phacoemulsification in allogeneic bone marrow transplant (allo-BMT) recipients.

DESIGN

Retrospective, noncomparative, interventional case series.

METHODS

Retrospective study of 34 eyes of 19 consecutive patients who had visually significant cataracts after allo-BMT and subsequently underwent phacoemulsification.

MAIN OUTCOME MEASURES

Best-corrected vision at the last follow-up visit and development of postoperative complications.

RESULTS

Surgery was done at a mean interval of 37 months after BMT, and the mean postoperative follow-up was 13 months. Twenty-one eyes (62%) had subnormal Schirmer I scores as a result of graft-versus-host disease (GVHD) involving the lacrimal gland. Of these, 71% (15 eyes) additionally had significant ocular surface epitheliopathy because of conjunctival GVHD. Frequent lubrication (95%), punctal occlusion (76%), topical steroids (33%), and other topical immunosuppressive therapies (14%) were used to manage GVHD-induced ocular surface disease before cataract surgery. Twelve patients (63%) also received systemic steroids and immunosuppressives. Patients proceeded to surgery only after their ocular surface disease was well controlled. Early postoperative complications included intraocular pressure elevation (three eyes), worsening of dry eye syndrome (two eyes), and corneal thinning (one eye). Posterior capsular opacification (PCO) requiring laser capsulotomy occurred in 44% of eyes. In eyes with preoperative conjunctival GVHD, 47% had recurrence with cessation of immunosuppressive therapy after surgery. Visual acuity at last follow-up visit was 20/30 or better in 33 (97%) eyes.

CONCLUSIONS

Phacoemulsification is an effective procedure in restoring vision in patients who have cataracts develop after BMT. However, coexisting ocular disease must be recognized and aggressively treated both before and after surgery to ensure good visual outcomes.

Cataract-free interval and severity of cataract after total body irradiation and bone marrow transplantation: influence of treatment parameters

PURPOSE

To determine prospectively the cataract-free interval (latency time) after total body irradiation (TBI) and bone marrow transplantation (BMT) and to assess accurately the final severity of the cataract.

METHODS AND MATERIALS

Ninety-three of the patients who received TBI as a part of their conditioning regimen for BMT between 1982 and 1995 were followed with respect to cataract formation. Included were only patients who had a follow-up period of at least 23 months. TBI was applied in one fraction of 8 Gy or two fractions of 5 or 6 Gy. Cataract-free period was assessed and in 56 patients, who could be followed until stabilization of the cataract had occurred, final severity of the cataract was determined using a classification system. With respect to final severity, two groups were analyzed: subclinical low-grade cataract and high-grade cataract. Cataract-free period and final severity were determined with respect to type of transplantation, TBI dose, and posttransplant variables such as graft versus host disease (GVHD) and steroid treatment.

RESULTS

Cataract incidence of the analyzed patients was 89%. Median time to develop a cataract was 58 months for autologous transplanted patients. For allogeneic transplanted patients treated or not treated with steroids, median times were 33 and 46 months, respectively. Final severity was not significantly different for autologous or allogeneic patients. In allogeneic patients, however, final severity was significantly different for patients who had or had not been treated with steroids for GVHD: 93% versus 35% high-grade cataract, respectively. Final severity was also different for patients receiving 1 x 8 or 2 x 5 Gy TBI, from patients receiving 2 x 6 Gy as conditioning therapy: 33% versus 79% high-grade cataract, respectively. The group of patients receiving 2 x 6 Gy comprised, however, more patients with steroid treatment for GVHD. So the high percentage of high-grade cataract in the 2 x 6 Gy group might also have been caused to a significant extent by steroid treatment. The percentage of patients with high-grade cataract was lower in allogeneic transplanted patients without steroid treatment for GVHD than in autologous transplanted patients: 35% versus 48%. An explanation for this could be pretransplant therapy containing high-dose steroids.

CONCLUSIONS

After high-dose-rate TBI in one or two fractions, steroids for GVHD influence latency time of a cataract and are of great importance for the severity the cataract finally attains. Although a cataract will develop in all patients, a clinically important high-grade cataract is relatively infrequent in patients not treated with steroids. Pretransplant therapy might also influence final severity of cataract.

Ocular findings in allogeneic stem cell transplantation without total body irradiation

OBJECTIVE

To evaluate the ophthalmologic complications in hematologic patients after allogeneic stem cell transplantation (ASCT) without total body irradiation.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

A total of 150 ASCT patients.

INTERVENTION

Ophthalmologic examinations of 130/150 patients were made, with particular attention to the occurrence of graft-versus-host disease (GVHD).

RESULTS

One hundred thirty patients with a mean age of 35.5 (SD 10.6) years at the time of ASCT were followed up for a mean of 12 months (range 3-60 months). GVHD developed in 73 patients (56.2%). Of 130 patients, 52 (40.0%) had ocular complications, and 29 (22.3%) of those had GVHD. Keratoconjunctivitis sicca was diagnosed in 13 (10.0%) patients, and 12 (9.2%) had different stages of pseudomembranous conjunctivitis. Cataract developed in 3 patients (2.3%) in the observation period, and 7 (5.4%) had keratitis. Six (4.6%) patients had uveitis, and 8 (6.2%) had retinal hemorrhages. No ischemic retinopathy was found. Bilateral optic disc edema developed in 10 (7.7%) patients.

CONCLUSIONS

Fewer ocular complications were observed in this series than in earlier studies, and the visual outcome was favorable. Cyclosporine has been linked to the development of optic disc edema and ischemic retinal lesions. The latter condition was not observed in the study patients, and the optic disc edema resolved within 1 year in all patients without any detectable visual impairment, in spite of continuation of the drug. Seven patients had acute GVHD at the time of optic disc edema, which is considered to be another manifestation of acute GVHD.

Ocular complications of pediatric bone marrow transplantation

OBJECTIVE

To investigate the ocular complications in pediatric bone marrow transplantation (BMT) patients.

DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 29 pediatric BMT patients were studied.

TESTING

Comprehensive ophthalmic check-up, including best-corrected visual acuity, intraocular pressure (IOP), Schirmer's test, tear breakup time, and slit-lamp and fundus examinations, was performed.

MAIN OUTCOME MEASURES

Tear film instability and its related complications, IOP, cataract, and fundus lesions were measured.

RESULTS

The mean age of patients was 9.1 years (range, 1.5-15 years). The mean post-BMT duration was 20.2 months (range, 3-54 months). Fifteen patients (51.7%) had tear abnormalities. Subconjunctival fibrosis was detected in two patients (6.9%). Dry and scaly skin of the eyelids was seen in one patient (3.4%). Lens opacities were found in 2 (33.3%) of 6 irradiated patients and 2 (8.7%) of 23 nonirradiated patients. Two patients (6.9%) had fundus changes, one with unilateral epiretinal membrane and the other with bilateral multiple discrete chorioretinal hypopigmented lesions in the middle to peripheral part of the retina. The overall complication rates for the anterior and posterior segments were 75.8% and 6.9%, respectively.

CONCLUSION

Ocular manifestations of BMT in children are not uncommon. The most common anterior segment problem is tear dysfunction. Posterior segment complications are less common but do exist. High rate of cataract formation is reported, and this probably is the most important long-term "amblyogenic" problem in these immature eyes. Awareness and management of these problems with routine eye examination and early intervention are recommended.

Management of complications of glucocorticoid therapy

Corticosteroids are commonly employed in the treatment of a wide variety of pulmonary disorders, including asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, sarcoidosis, and pulmonary vasculitides; as well as in the lung transplant population. Frequently, steroid-induced complications contribute significantly to morbidity and diminished quality of life, often overshadowing the impact of the underlying lung disease. This article will discuss the more commonly encountered complications of corticosteroids in the context of the method of delivery, events occurring with chronic use, and events related to withdrawal.

Ocular toxicity and cancer chemotherapy. A review

BACKGROUND

Systemic anticancer therapies can produce acute and chronic organ damage, but the eye is usually considered a protected site. Nonetheless, the oculo-visual system has a potentially high degree of sensitivity to toxic substances. Ocular toxicity induced by cancer chemotherapy includes a broad spectrum of disorders, reflecting the unique anatomic, physiologic, and biochemical features of this essential organ.

METHODS

A review of the literature regarding the ocular toxicity of chemotherapeutic agents, hormonal agents, biologic agents, and high dose chemotherapy with allogeneic and autologous bone marrow transplantation was conducted.

RESULTS

Ocular toxicity induced by anticancer chemotherapy is not uncommon. The development of more aggressive regimens as well as new agents and combination chemotherapies have resulted in a significant increase of reported cases of chemotherapy-induced ocular side effects. In most instances, the mechanisms of ocular toxicity continue to be poorly understood.

CONCLUSIONS

Ocular toxicities induced by chemotherapeutic agents are generally not preventable; therefore, clinicians must be aware of potential vision-threatening complications. Prompt consultation with an ophthalmologist can lead to early detection, proper diagnosis, and appropriate therapeutic measures. Dose reduction or discontinuation of incriminated drugs may help in reducing the severity and the duration of side effects.

Eye shielding for patients treated with total body irradiation

The incidence of cataracts in patients who have received total body irradiation (TBI) is about 20% and increases to 40% if the patient is treated for graft-versus-host disease. At our institution, all TBI patients are treated with two lateral opposed 24 MV photon fields. No attempt is usually made to shield the eyes during the TBI treatment because of the amount of lead required to adequately attenuate megavoltage photon beams, the difficulty in properly positioning an eye shield and the possibility of compromising the effectiveness of the treatment. However, we were asked to treat a TBI patient who is a professional pilot, and thus his livelihood is contingent upon maintaining perfect vision. A custom eye shield was constructed out of lead and ionization chamber and film measurements were performed under TBI conditions to determine the thickness and location of the eye block to optimize the competing effects of increased scatter and attenuation from the lead. Phantom data were also obtained for 6 MV irradiation for comparison with 24 MV. In-vivo patient and phantom measurements with thermoluminescent dosimeters showed that with visual positioning of the eye block the dose was reduced from 16 to 20% across the orbits of both eyes.

Infantile cataracts

Cataracts are one of the most treatable causes of visual impairment during infancy. Recent epidemiological studies have shown that they have a prevalence of 1.2 to 6.0 cases per 10,000 infants. The morphology of infantile cataracts can be helpful in establishing their etiology and prognosis. Early surgery and optical correction have resulted in an improved outcome for infants with either unilateral or bilateral cataracts. While contact lenses continue to be the standard means of optically correcting an infant's eyes after cataract surgery, intraocular lenses are gaining in popularity as an alternative means of optically correcting these eyes. Post-operative complications occur more commonly after infantile than adult cataract surgery and many of these complications do not develop until years later. As a result, it is critical that children be followed closely on a long term basis after infantile cataract surgery.

Efficacy and toxicity of radiation in preparative regimens for pediatric stem cell transplantation. II: Deleterious consequences

There has been a dramatic improvement in the treatment of both allogeneic and autologous stem cell transplants, especially in children and young adults. However, attempts to apply more intensive conditioning treatments to the more refractory pediatric malignancies have also increased the risks of deleterious consequences. This review examines the risks, and reports important variations in the toxic effects of using different conditioning techniques.