Maarten P. Mourits

Quantification of orbital and mid-facial growth retardation after megavoltage external beam irradiation in children with retinoblastoma

PURPOSE The late side effects of external beam irradiation in patients with retinoblastoma such as orbital bony growth retardation, are a serious problem in adolescence. Therefore, a quantitative study was performed to investigate the late effects of irradiation on orbital growth in patients with retinoblastoma. METHODS The orbits of 68 patients with retinoblastoma, 52 bilateral and 16 unilateral, were divided into two treatment groups: radiotherapy alone, 77 orbits; and radiotherapy + enucleation, 43 orbits. Follow-up time was 12 to 240 months (mean, 95 months) in group 1 and 27 to 216 months (mean, 97 months) in group 2. These groups were subdivided further into age groups at which radiotherapy was given. The morphometric measurements of these groups were compared. RESULTS The authors showed that irradiation causes a significant growth retardation when compared with the growth of nonirradiated orbits (P<0.001). They also demonstrated that radiotherapy in children younger than 6 months of age is more damaging to the orbital growth than at an older age (P<0.01). Finally, the authors showed that secondary enucleation does not have an additive growth-retarding effect. CONCLUSION Orbital growth retardation in patients with retinoblastoma after radiotherapy is influenced mainly by the age at which irradiation is given and is defined at 6 months. Theoretically, it would be desirable to postpone irradiation in children until they are older than 6 months of age if possible. The irradiation effect on these orbits is not enhanced by enucleation.

Comparison of artificial eye amplitudes with acrylic and hydroxyapatite spherical enucleation implants

PURPOSE To compare artificial eye amplitudes in patients who randomly received either a hydroxyapatite or an acrylic, scleral-covered spherical implant after enucleation. DESIGN Randomized, controlled trial. PARTICIPANTS Thirty-four consecutive patients who underwent enucleation because of an intraocular melanoma and 21 healthy control participants from the hospital staff. METHODS Eligible patients randomly received a hydroxyapatite or an acrylic, scleral-covered spherical orbital implant. Fourteen patients were fitted with a hydroxyapatite implant, and 16 were fitted with an acrylic implant. We measured horizontal and vertical saccadic amplitudes of both the artificial eye and the healthy eye. Measurements were performed with the magnetic search coils technique. Saccadic amplitudes of the artificial eye were compared with the healthy eye of the patient. The amplitudes of the healthy eyes were compared with saccadic amplitudes of control participants. The interval from surgery to measurements was at least 3 months in all patients. Saccadic gain (artificial eye and eye amplitude divided by target amplitude) and saccadic symmetry (artificial eye amplitude divided by healthy eye amplitude) were calculated. MAIN OUTCOME MEASURES Saccadic gain and saccadic symmetry. RESULTS The gain in the healthy eyes of the patients was comparable with the gain of the control eyes. Saccadic symmetry was 1.0 in control participants. In patients, it was 0.334 in horizontal saccades and 0.577 in vertical saccades. However, saccadic symmetry did not differ significantly between the acrylic group and the hydroxyapatite group (P: > 0.1 for any saccadic direction). Equivalence was detectable with a power more than 90% for horizontal saccades and more than 80% for vertical saccades. Curvilinearity was rejected for both patient groups and for all saccadic directions (P: > 0.5). CONCLUSIONS When no motility peg is placed, acrylic and hydroxyapatite spherical implants yield comparable saccadic amplitudes of the artificial eye. Artificial eye amplitudes were markedly more restricted horizontally than vertically. In all saccadic directions, the relation between target amplitude and artificial eye amplitude was linear.

Radiologic Measurement of Extraocular Muscle Volumes in Patients with Graves' Orbitopathy: A Review and Guideline

Objective: To evaluate and compare techniques for extraocular muscle (EOM) volume measurement and to provide guidelines for future measurements. Design: Systematic review. Results: Existing techniques used to measure extraocular muscle volumes on radiologic scans can be divided into manual outlining, computer assisted and automated segmentation. Both computed tomography (CT) and magnetic resonance (MR) image datasets can be used. On CT scans, one best measures muscle volume using region grow segmentation, accepting an overestimation of true volume by inevitable inclusion of non-muscular tissue. On high resolution MRI scans, single muscles can be outlined manually, but measurements include only part of the muscle due to poor tissue contrast at the orbital apex. Measurement errors can be reduced 3.5% by exact horizontal repositioning. A measured volume change of at least 6–17% is required to demonstrate a significant difference. Conclusion: Currently the best choice for EOM volume measurements on CT images is computer assisted grey value segmentation and on MRI images is manual outlining of individual muscles. Because of the time required and the complexity of the measurements, present EOM volume measurement is as yet only suitable for research purposes.

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.

Cataract after total body irradiation and bone marrow transplantation: degree of visual impairment.

PURPOSE To assess the degree of visual impairment as a result of cataract formation after total body irradiation (TBI) for bone marrow transplantation. METHODS AND MATERIALS The data from 93 patients who received TBI in 1 or 2 fractions as a part of their conditioning regimen for bone marrow transplantation were analyzed with respect to the degree of visual impairment as a result of cataract formation. The probability to develop severe visual impairment (SVI) was determined for all patients, and the degree of visual impairment was assessed for 56 patients with stabilized cataract, using three categories: no, mild, or severe. RESULTS For all 93 patients, the probability of developing a cataract causing SVI was 0.44. For allogeneic patients, it was 0.33 without and 0.71 with steroid treatment (p <0.001). All SVI-free probability curves reached a plateau distinct from the cataract-free curves. Apparently, cataracts developing late in the follow-up period rarely cause SVI. Of the patients with stabilized cataract, 32% had no visual impairment, 16% had mild, and 52% severe impairment. No or mild visual impairment was present in 61% of all patients with stable cataract and no steroid treatment compared with only 13% of the patients treated with steroids (p = 0.035). CONCLUSION SVI occurs in only some of the patients (52%) with stable cataract after TBI for bone marrow transplantation in 1 or 2 fractions. Steroid treatment markedly increases the probability of developing visual problems as result of a cataract after TBI.

Assessment of Disease Activity

“Active” disease refers to the stage in which manifestations appear, or become worse, and the patient progressively experiences the negative consequences of the disease. This in contrast to the inactive, or burnt out stage of the disease in which the disease process is stable, although the patient may still be considerably handicapped. In Graves’ ophthalmopathy (GO) patients initially have red, painful, watering eyes and swollen and retracted eyelids. Their eyes start to protrude, eye movements become painful and restricted, and vision may diminish. Basedow, in one of the first descriptions (1) of Graves’ disease, reported that after an initial stage of ever increasing complaints an improvement took place (“eine reelle Besserung hervor, auch der Exophthalmos verminderte sich”). This has been the experience of other clinicians as well (2). The eyes become white again, the eyelids more puffy than swollen, and pain disappears. But contrary to Basedow’s observations, proptosis persists (with lid retraction, in some cases) and severe motility impairment only improves to a certain extent, leaving the patient with double vision at least in the extremes of gaze. Figure 1 illustrates these two stages of the disease.

Editorial: Junior Award

At the annual general meeting of the European Society of Ophthalmic Plastic and Reconstructive Surgery in Gallivare, Sweden, June 1989, Dr. Friedrich Hailing and Professor Holge Busse, both from Germany, suggested establishing an annual prize to encourage young ophthalmologists doing research in the field of oculoplastic surgery.