Comparison of uveal parameters between acute primary angle-closure eyes and fellow eyes in South Indian population

Purpose:To analyze the ocular biometric parameters of eyes with acute primary angle closure (APAC) as compared to fellow eyes.Methods:A cross-sectional study was conducted on 27 patients presenting with recent onset APAC to a tertiary eye institute in India. Anterior and posterior ocular biometric parameters were measured simultaneously by anterior segment optical coherence tomography (AS-OCT), A-scan, ultrasound biomicroscopy (UBM), and B-mode ultrasonogram (USG). The parameters measured were anterior chamber depth (ACD), anterior chamber angle (ACA), angle opening distance (AOD500, AOD750), lens vault (LV), axial length (AL), ciliary body thickness maximum (CBTmax) and at the point of scleral spur (CBT0), anterior placement of the ciliary body (APCB), and retinochoroidal thickness (RCS).Results:Mean age ± SD of patients with APAC was 55.66 ± 7.2 years with female preponderance (21:6 patients). Mean presenting IOP ± SD of the affected eye and fellow eye were 54.74 ± 11.67 mm Hg and 18.7 ± 11.67 mm Hg, respectively. Eyes with APAC had statistically significant narrower anterior ocular biometric parameters, higher LV, decreased ciliary body thickness, more APCB, and longer AL than the fellow eyes. CBTmax is the only variable that had significance (b = −0.421,95% CI: −0.806 to − 0.035, P = 0.034) in the univariate analysis with RCS thickness in APAC eyes. Further, there was a correlation between CBT0 and APCB with CBTmax both in univariate (b = 0.894, P < 0.0001 and b = −0.351, P = 0.039) and multivariable analysis (b = 0.911, P < 0.0001 and b = −0.416, P = 0.016)Conclusion:Compared to the fellow eyes, APAC eyes had different ocular biometric parameters. In addition to known biometric parameters associated with pupillary block (narrower anterior biometric parameters-ACA, ACD, and AOD), our study found multiple nonpupillary block factors such as higher lens vault and thinner and more anteriorly placed ciliary body to be associated with APAC.     

Posterior uveal melanomas in aphakic and pseudophakic eyes

Of 650 eyes with posterior uveal melanomas that were accessioned at the Armed Forces Institute of Pathology from 1975 to 1983, 28 were aphakic and eight were pseudophakic. In ten of these 36 cases, the cataract had been unilateral. Only two patients had been examined with preoperative A-scan ultrasonography to obtain the axial length of the eye. None of the patients had been examined for possible intraocular tumors by either A- or B-scan ultrasonography. We believe that in many of these cases the tumor was large enough to have been detected at the time of cataract surgery. Thus, if the lens is too opaque for the fundus to be viewed, B-scan ultrasonography should be used before cataract extraction.     

Malignant change in melanocytomas of the uveal tract

Melanocytomas are pigmented tumors of the uvea and optic nerve head composed of plump polyhedral melanocytes which have been regarded as nevus cells. There are few reports of malignant change in these usually benign lesions. This study documents 16 cases of malignant melanoma of the uvea, eight of which were characterized by the presence of plump polyhedral melanocytes in and around the tumor. The melanocytoma cells were aggregated throughout the tumors and/or at the margins of the lesions; these cells did not appear between the melanoma and the sclera, as has been reported with spindle-type nevus cells. Electron micrographs of these plump melanocytes had the characteristics of common uveal melanocytes, while the tumor cells had features of malignant melanoma cells. The clinician should recognize the potential of melanocytomas for undergoing malignant change and should follow patients who have this lesion with this in mind. Article is followed by comments of Dr. L. E. Zimmerman.     

Response of rabbit ciliary process cyclic nucleotides to specific phosphodiesterase inhibitors

PURPOSE: To determine which cyclic nucleotide phosphodiesterase family activities can be identified in rabbit ciliary processes. METHODS: Freshly excised rabbit ciliary processes were incubated in vitro with family selective phosphodiesterase inhibitors in the absence or presence of activators of soluble or membrane bound guanylate cyclase. The resulting increases of cyclic AMP and cyclic GMP were measured by RIA. RESULTS: Rabbit ciliary process cyclic AMP levels were increased by the phosphodiesterase 1 and 4 selective inhibitors, 8-methoxymethyl-IBMX and rolipram, respectively. Cyclic GMP levels were increased by 8-methoxymethyl-IBMX; whereas the phosphodiesterase 5 and 6 selective inhibitor, zaprinast, increased cyclic GMP little. Nitric oxide donors increased cyclic AMP in addition to cyclic GMP, and inhibition of soluble guanylate cyclase eliminated the increase of cyclic AMP. The effects of sodium nitroprusside and the phosphodiesterase 3 selective inhibitor, cilostamide, on cyclic AMP were not additive suggesting that the sodium nitroprusside mediated increase of cyclic GMP, like cilostamide, inhibited phosphodiesterase 3. CONCLUSIONS: Cyclic AMP in rabbit ciliary processes is hydrolyzed primarily by phosphodiesterases 1 and 4, and, when cyclic GMP levels are low, by phosphodiesterase 3; cyclic GMP is hydrolyzed primarily by phosphodiesterase 1.     

The histoarchitectonics of the uveal tract vessels in the rabbit eye in the dynamics of the burn process]

By means of injecting soot into the vessels of the uveal tract of the rabbit eye the character of changes in the architectonics of the vascular bed in dynamics of the burn process could be detected. It was found that a burn trauma produces changes in practically the whole uveal tract, but to a greater extent, in its anterior segment. Reduction of blood filling of the vessels or their total segmentary "switching-off" is connected with the development of reversible (thrombosis, oedema of endotheliocytes and surrounding stroma, hemolysis) and irreversible (destruction of the vascular wall, obliteration of vessels) structural changes. The degree of disturbances in blood circulation and reversibility of these changes depend on the severity of the burn. In case of less severe burns, total structural restoration of the vascular network in the nearest time is recorded, while in severe burns--partial restoration with elements of vascular net reconstruction of adaptive character.