Uveal and Conjunctival Malignant Melanoma in Denmark, 1943–97: Incidence and Validation Study

PURPOSE

To study the incidence of malignant melanoma in the ocular region in Denmark during the period 1943-97.

METHODS

The patients were mainly identified through the Danish Cancer Registry. Age-period-cohort modelling of the incidence rates was done based on age at diagnosis, calendar period and birth cohort in 5-year groups and for each gender.

RESULTS

The age-standardized incidence of malignant melanoma in the ocular region was 0.78 for men (N = 1327) and 0.65 for women (N = 1242) per 100,000 person-years. Calendar period and birth cohort had no effect on the incidence in the ocular region or in the topography subgroups choroid/ciliary body and conjunctiva. However, the incidence increased with birth cohort for iris melanomas.

CONCLUSIONS

The incidence of malignant melanoma in the ocular region was stable in contrast to a major increase in cutaneous melanoma in Denmark during the period 1943-97. The incidence of iris melanomas increased substantially, whereas the rate was stable for choroid/ciliary body and conjunctival melanomas.

Uveal and Conjunctival Malignant Melanoma in Denmark 1943–97: Observed and Relative Survival of Patients Followed Through 2002

PURPOSE

To evaluate the observed and relative survival of patients diagnosed with a malignant melanoma in the ocular region in Denmark during the period 1943-97.

METHODS

The study included 2,504 patients (1,292 men and 1,212 women) diagnosed with a melanoma in the ocular region, of which 2,434 cases could be topographically subclassified into 2,178 in the choroid/ciliary body, 141 in the iris, and 115 in the conjunctiva. The patients were followed through 2002 and the observed survival proportions and relative survival ratios were estimated.

RESULTS

For the total ocular region and the choroid/ciliary body, the observed survival did not vary statistically significantly with the year of diagnosis. A statistically insignificant higher observed survival for women than men was found for tumors in the ocular region and the subgroups choroid/ciliary body, iris, and conjunctiva. During the 55-year study period, the 5- and 10-year relative survival remained stable for the ocular region for men at 67% and 57% and for women at 71% and 60%, respectively, and stable for the choroid/ciliary body for men at 66% and 55% and for women at 69% and 57%, respectively. The 5- and 10-year relative survival for the iris was for men 90% and 85% and for women 99% and 101%, respectively, and for the conjunctiva for men 83% and 70% and for women 93% and 82%, respectively.

CONCLUSION

The observed and relative survival of patients diagnosed with a melanoma in the ocular region and choroid/ciliary body in Denmark during the period 1943-97 and followed through 2002 has remained stable. The highest observed and relative survival was found for iris melanomas, the lowest for choroid/ciliary body melanomas, and intermediate for conjunctival melanomas.

CNS metastasis from malignant uveal melanoma: a clinical and histopathological characterisation

AIM

To characterise uveal melanoma that has metastasised to the central nervous system (CNS).

METHODS

Review of 2365 patients constituting all patients diagnosed as having primary uveal melanoma in Denmark during the period 1943-1997. All patients with malignant uveal melanoma and metastasis to the CNS were identified. For each patient, clinical and histopathological data were gathered.

RESULTS

Sixteen patients with CNS metastasis were identified. The median age was 58 years. The majority of CNS metastases were located in the frontal and parietal lobes. Eleven patients had widespread metastases. Five patients had exclusively metastasis to the CNS. The average time from diagnosis of primary tumour to symptoms of CNS metastasis was 91 months. The average time from the initial CNS symptoms to death was 20 months. All tumours were composed of either mixed or spindle cells. The average largest basal diameter of the primary tumours was 12 mm. One tumour was a ring melanoma. The majority of tumours had a ruptured Bruch membrane. Retinal invasion was observed in 36% of tumours. No specimen had optic nerve invasion. Scleral invasion was pronounced in 36% of cases, and extrascleral extension was observed in two cases (14%). The amount of tumour infiltrating lymphocytes was pronounced in three cases (23%).

CONCLUSION

The proportion of uveal melanoma patients having CNS metastasis was 0.7%. Eleven patients had multiple organ metastases, and the average time from the initial CNS symptoms to death was 8 months. Five patients had metastasis to the CNS solely, and the average time from the initial CNS symptoms to death was 57 months.

Stability of graft refractive power after penetrating keratoplasty

PURPOSE

Patients needing penetrating keratoplasty (PK) and cataract extraction with intraocular lens (IOL) implantation may be handled with a single triple procedure or a two-stage procedure with initial keratoplasty and cataract surgery in a later session. The latter approach is considered more safe by some surgeons and allows adjustment of the IOL power to the power of the actual corneal graft. The purpose of this study was to estimate the optimal timing of cataract surgery with IOL implantation by studying the refractive stability of 8 mm penetrating keratoplasty grafts.

METHODS

Penetrating keratoplasty (8.0 mm graft and recipient bed) was performed in 28 eyes of 28 patients. Corneal topography (TMS-1) was studied at 1, 2, 3, 6, and 12 months after surgery and after suture removal (30 months). The central spherical equivalent graft power was computed from the topographical data (rings 2 through 4).

RESULTS

On average, the spherical equivalent graft power was stable from one month after surgery up to suture removal (range: 41.9 to 42.7 diopters). After suture removal the graft steepened slightly (0.7 diopters). Corneal refractive power of single grafts fluctuated considerably over time. The standard deviation on time-dependent changes in graft power was from 3 months efter PK smaller than the standard deviation on the graft powers at 12 months.

CONCLUSION

The average central spherical equivalent power of an 8.0 mm donor graft in an 8.0 mm recipient bed was stable from one month after penetrating keratoplasty until suture removal. A two-stage procedure with cataract surgery performed 3 months after PK can, compared to the triple procedure, reduce postoperative ametropia at 12 months if graft topography is taken into consideration at the time of cataract surgery. We recommend that cataract surgery with IOL implantation takes place from 3 months after penetrating keratoplasty.

Comparison of endothelial cell density estimated by contact and non-contact specular microscopy

PURPOSE

To compare a contact and a non-contact specular microscope in the determination of endothelial cell density.

SUBJECTS AND METHODS

One hundred and twenty-one eyes from 70 patients who had undergone various degrees of photorefractive keratectomy for myopia were included. The endothelium was imaged by contact (Konan Clinical Specular Microscope) and non-contact (Topcon SP-1000) specular microscopy and the endothelial cell density estimated.

RESULTS

The average endothelial cell density achieved by the contact specular microscope was 3011+/-298 cells/mm2 (mean+/-SD, n=121) and by the non-contact specular microscope 3015+/-265 cells/mm2 (n= 121). The difference in endothelial cell density between the contact and the non-contact specular microscope (contact minus non-contact) was -4+/-175 cells/mm2 (t=0.26, 2p>0.05 in a paired t-test). The sampling error on the estimated endothelial cell density was 76 cells/mm2 for the contact specular microscope and 74 cells/mm2 for the non-contact specular microscope.

CONCLUSION

The average endothelial cell density and the precision of the measuring technique were similar for the contact and the non-contact specular microscope. Furthermore, the endothelial cell densities estimated by the two instruments at various values of anterior central corneal refractive power and central corneal thickness were similar. The two instruments can be used interchangeably.

Magnification changes in specular microscopy after corneal refractive surgery

PURPOSE

To describe the effect of corneal refractive surgery on the magnification of a contact and a non-contact specular microscope.

METHOD

The magnification of a contact specular microscope (Konan Clinical Specular Microscope) and a non-contact specular microscope (Topcon SP-1000) was experimentally and theoretically studied as a function of anterior corneal refractive power and central corneal thickness.

RESULTS

The magnification of the contact and non-contact specular microscope was found to decrease slightly with decreasing central corneal thickness. In addition, the magnification of the non-contact specular microscope decreased slightly with decreasing anterior corneal refractive power.

CONCLUSION

As the preoperative and postoperative measuring conditions are different in patients undergoing corneal refractive surgery a correction for magnification changes is necessary when small changes in endothelial cell density are looked for.

Endothelial cell loss after photorefractive keratectomy for myopia

PURPOSE

To study the long-term effect of 193 nm excimer laser photorefractive keratectomy (PRK) on the human corneal endothelial cell density.

SUBJECTS AND METHODS

One hundred and twenty-four eyes from 71 patients underwent photorefractive keratectomy for myopia or myopic-astigmatism. Endothelial cell density was examined a short time before the operation and on an average of 50 months after the operation using a contact specular microscope. A subgroup of 32 eyes from 20 patients treated only once was examined preoperatively and 7 and 52 months postoperatively. The endothelial cell densities were corrected for the changing magnification of the contact specular microscope with changing central corneal thickness and for the expected physiological cell loss with time.

RESULTS

The average endothelial cell density was preoperatively 3098+/-283 cells/mm2 (mean+/-SD) and postoperatively 3048+/-294 cells/mm2 corresponding to a change of -50+/-157 cells/mm2. This was statistically significantly different from zero in a paired t-test (n=124, t=3.58, 2p<0.001). The average changes in endothelial cell density for the subgroup were -34+/-159 cells/mm2 for the postoperative time interval 0-7 months and -20+/-188 cells/mm2 for the postoperative time interval 7-52 months. These results were not statistically significantly different from zero in a paired t-test (n=32, t=1.21 and t=0.60, 2p>0.05). A statistically significant negative correlation between preoperative cell density and the change in cell density was found (n=124, r=-0.21, 2p<0.05).

CONCLUSION

This study suggests a potentially harmful effect of PRK on the human corneal endothelium. It appears that most cells are lost during ablation or within the first period of time after PRK.

The effect of 193 nm excimer laser radiation on the human corneal endothelial cell density

The effect of 193 nm excimer laser radiation on human corneal endothelial cell density was examined. Fifty-five eyes from 35 patients underwent photorefractive keratectomy for myopia. Photomicrographs of the endothelium were taken a short time before the operation and on an average of 7 months postoperatively with a specular microscope. The average endothelial cell densities were preoperatively 3375 +/- 266 cell/mm2 (mean +/- SD) and postoperatively 3348 +/- 287 cells/mm2, corresponding to a fall of 27 cells/mm2 (N = 55). This fall in endothelial cell density was not statistically significant. A significant correlation between the change in cell density and age of the patient was found, with older patients losing more cells (N = 35, 2p < 0.05). The magnification of the specular microscope was found to change with corneal thickness. The importance of correcting the endothelial cell densities for corneal thickness is discussed.