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Objective: To characterize the ocular fundus findings of patients who suffered sudden visual loss associated with sexual activity. Design: Case series. Setting: Outpatient ophthalmic practice. Patients: Six patients presented with a precipitous decrease in vision in one eye with no apparent predisposing factors. After obtaining a careful history, each patient revealed that he or she had been engaging in rigorous sexual activity immediately before experiencing the visual loss. Intervention: Five of the six patients were followed up without intervention. One patient required prophylactic laser photocoagulation of a retinal tear to decrease the risk of retinal detachment. Results: Six patients aged 24 to 53 years suffered sudden loss of vision secondary to intraretinal, preretinal, or vitreous hemorrhaging. Visual acuity in the affected eyes ranged from a mild decrease (20/40) to profound visual loss (counting fingers at 6 in). Five of the six patients were followed up for at least 1 month and showed spontaneous improvement in vision as the blood cleared. Those who returned for long-term follow-up enjoyed complete visual recovery without any sequelae. Conclusions: Sudden debilitating visual loss may occur during sexual activity from the rupture of retinal blood vessels in the macular region or from the development of vitreous bleeding from an induced retinal tear. The longterm prognosis after such hemorrhaging appears to be excellent, with good visual recovery occurring as the blood resorbs spontaneously.

Inversion in a head-down position (gravity inversion) results in an intraocular pressure of 35 to 40 mm Hg in normal subjects. We used computerized static perimetry to measure the visual fields of normal subjects during gravity inversion. There were no visual field changes in the central 6 degrees of the visual field compared with the baseline (preinversion) values. However, when the central 30 degrees of the visual field was tested, reversible visual field defects were found in 11 of 19 eyes. We believe that the substantial elevation of intraocular pressure during gravity inversion may pose potential risks to the eyes, and we recommend that inversion for extended periods of time be avoided.

• The intraocular pressure (IOP) in humans approximately doubles when a head-down, or inverted, position is assumed. Simultaneously, the ophthalmic artery pressure increases by an even greater absolute magnitude. We recorded pattern reversal visual evoked potentials (PRVEPs) in 16 subjects in both the inverted and upright positions. In ten of the 16 subjects, we performed an additional experiment. On a different day, we obtained control PRVEPs, and then, using a scleral suction cup, we artificially increased the IOPs to the same values reached when the subjects were previously inverted. We found that the PRVEP amplitudes were significantly reduced in both experiments compared with corresponding control recordings, without changes in latency or wave form. Furthermore, the degree of amplitude reduction was even greater during gravity inversion than with suction cup elevation of IOP. The effects of IOP on optic nerve function as measured by the PRVEP appear to be dependent more on the IOP than on vascular perfusion. We also concluded that gravity inversion activities pose potential risks to the eyes.

Twenty patients with unilateral exophthalmos secondary to orbital tumors underwent fundus photography; 16 underwent fluorescein angiography. Choroidal folds were found in 15 eyes. The location of each tumor with respect to the globe was determined by computed tomography. In addition, most patients underwent B-scan ultrasonography and surgical exploratory procedures. Choroidal folds were more common in patients with greater amounts of exophthalmos and with anteriorly located tumors. Moreover, the pattern of choroidal folds generally reflected the location of the tumor within the orbit. Comparison with the uninvolved fellow eyes showed that preoperative refractive errors were usually shifted toward hyperopia with intraconal tumors, whereas extraconal tumors were typically associated with higher astigmatic errors on the involved side.

• A small, minimally elevated, nonpigmented choroidal tumor increased in volume 12-fold and grew from the edge of the fovea to the optic disk within 60 days. Histopathology of the enucleated globe demonstrated a mixed spindle and epithelioid cell malignant melanoma with numerous mitotic figures. The calculated doubling time of this tumor was 17 days.

Ceftriaxone's toxic effects were assessed in albino rabbits after intravitreal injection. Doses up to 5 mg did not alter the B-wave amplitude. Following 7.5-and 20-mg doses, B-wave amplitude ratios were depressed at 24 hours and normal at seven and 14 days. A 50-mg dose caused a temporarily flat B-wave 24 hours after injection. At two weeks this ratio exhibited a moderate increase but remained 2 SDs below the mean preinjection ratio. Eyes receiving up to 20 mg were normal histologically at 14 days. A 50-mg dose induced generalized retinal edema and disruption of the retinal layers 24 hours after injection; at two weeks there were no histologic changes in the retina. Immediately after a 2-mg intravitreal injection, vitreous ceftriaxone levels were 1,345 +/- 4.9 mg/L; by 72 hours they had decreased to 17.6 +/- 1.4 mg/L. The mean peak aqueous level was 80.2 +/- 12.2 mg/L at 72 hours.