Marine organisms as heavy metal bioindicators in the Persian Gulf and the Gulf of Oman.

In the present study, cadmium and lead concentrations were compared in barnacles, ghost shrimps, polychaetes, bivalves, and sediment from ten different locations along the intertidal zone of the Persian Gulf and the Gulf of Oman. The results revealed significant differences in the heavy metal concentrations between the organisms with barnacles showing, by far, the highest metal concentrations. The bioaccumulation factor of Cd in different animals follows this pattern with barnacles>bivalves>polychaetes>ghost shrimps, while the pattern for Pb was barnacles>polychaetes>bivalves>ghost shrimps. In most of the stations, sediments showed the lowest lead and cadmium concentrations. Therefore, it is concluded that barnacles with Pb concentrations between 0.17 and 2,016.1 µg/g and Cd concentrations ranging from 0.4 to 147.1 µg/g are the best organisms to be employed in monitoring programs designed to assess pollution with bioavailable metals in the Persian Gulf and the Gulf of Oman.

Evaluation of lens opacities classification system III applied at the slitlamp.

The Lens Opacities Classification Systems (LOCS III) was developed and standardized using photograding. The purpose of this study was to assess the validity of LOCS III at the slitlamp and to compare slitlamp with photograding. To do so, two independent observers graded cataract at the slitlamp and in photographs from two sets of patients; the first set consisted of 205 eyes (193 acceptable photographs) and the second set of 51 eyes (51 photographs). The 95% tolerance limits (TL) for grading at the slitlamp ranged from 0.9 to 1.8 for the first set and 0.6 to 1.2 for the second (intraclass correlation coefficients 0.79 to 0.91 vs. 0.70 to 0.97, respectively). Specifically, there was a significant decrease in 95% TL for cortical and nuclear color. For the first set of photograding, the 95% TL were 0.3 to 0.6 between the two observers and 0.6 to 0.8 for the same observer at two different sessions. Similar results were found for photograding the second set. The 95% TL for comparing slitlamp and photograding were generally > 1.0. The results suggest that (1) LOCS III at the slitlamp has 95% TL only slightly worse than those for LOCS III photogradings; (2) LOCS III slitlamp grading for cortical and nuclear color improves with practice; and (3) the slitlamp and photographic gradings cannot be used interchangeably.

Objective line spread function measurements, Snellen acuity, and LOCS II classification in patients with cataract.

We tested an instrument to measure the line spread function (LSF) of the eye in order to assess objectively retinal image degradation due to cataract. Optical aberrations from 62 eyes with early to moderate cataract were assessed by measuring the extent of blurring of a best-focused fine line image (LSF) projected onto a subject's retina. The instrument consisted of a slitlamp equipped with a Hruby lens to project the line and a computer-coupled CCD camera to record and measure the blurred image. We hypothesized that the width of the blurred line image (called WSCAT) due to light scattering in the cataractous lens would be affected most by nuclear and subcapsular cataracts. The WSCAT results were compared to the data from two other tests: (1) Snellen acuity and (2) LOCS II cataract classification. Grouping eyes by Snellen acuity we found that WSCAT from the group with 6/4.5 (20/15) or 6/6 (20/20) acuity was distinguishable from the group with 6/9 (20/30) or worse acuity (95% confidence interval). Data also were analyzed using a regression model which corrects for the intraclass correlation between the two eyes of an individual. Results show a significant association between WSCAT and minimum angular resolution (MAR) derived from Snellen visual acuity (regression coefficient of 5.45, p = 0.008). WSCAT also is correlated with both LOCS II nuclear opalescence (NO) and posterior subcapsular (P) categories with regression coefficients of 3.03 (p = 0.004) and 2.07 (p = 0.054), respectively. Results from measurement of LSF indicate the potential for this instrument to assess retinal image degradation associated with nuclear and posterior subcapsular cataract objectively.

Herpes zoster ophthalmicus.

Herpes zoster ophthalmicus occurs worldwide, usually in healthy adults, but, increasingly in patients who are immunocompromised. After primary varicella infection (chickenpox), the virus lies dormant in the sensory ganglion until it becomes reactivated as zoster. Involvement of the ophthalmic branch of the trigeminal nerve is characterized early by corneal dysesthesia and dendritiform keratopathy, and these are self-limited. However, smoldering disease may cause pathological changes in the ocular structures through direct invasion of virus, secondary inflammation, and alterations of autoimmune mechanisms. Antiviral agents have demonstrated some success in resolving early signs and symptoms, but their role in preventing and treating late complications remains to be fully studied. Until a definitive antiviral agent is established, the benefits of steroid use in certain acute inflammatory processes outweight its risk of reducing host immunity. Corneal complications of herpes zoster ophthalmicus sometimes require surgical intervention.