[On the prophylactic treatment in retinal detachment (author's transl)]

Within a period of three years, 152 eyes in 149 patients underwent prophylactic treatment for retinal lesions. The elements are considered that would move the surgeon to propose to the patient a prophylactic treatment. No complications were found in any of the eyes that were treated, however a retinal detachment occurred in two eyes, 6 to 8 months after treatment. Retinal lesions treated by prophylactic means are compared with those found in 500 eyes operated for retinal detachment during the same period. The results of this study leads to the conclusion that a real risk of retinal detachment is more dangerous than the possible consequences of prophylactic treatment.

Retinal oxygenation via the choroidal circulation

The possibility of supplying normal amounts of oxygen to the inner layers of the retina by diffusion from the choroid in the presence of retinal arterial obstruction was studied in cats and rhesus monkeys. While the animals were under general anesthesia, an oxygen electrode was placed in the vitreous cavity immediately adjacent to the retina, and a retinal artery blocker probe was used to occlude various segments of the retina blood supply. The inspired oxygen concentration was alternated between 20% and 100%. The choroidal circulation was intermittently occluded by elevating the intraocular pressure. In all animals it was possible to return the oxygen tension of the innermost retina to normal concentrations or above while the retinal arterial circulation alone was occluded, by having the animal breathe 100% oxygen at one atmosphere pressure. This could not be done when the intraocular pressure was elevated to 85 mm Hg, occluding the choroidal as well as the retinal circulation. The electroretinogram and the visually evoked response were recorded in cats while the retinal circulation was occluded and the inspired oxygen concentration changed from 20% to 100% at one atmosphere pressure. The electroretinogram and the visually evoked response were extinguished by occluding the retinal circulation while the animal was breathing 20% oxygen, and these responses were returned to normal by changing to a 100% inspired oxygen concentration.

Photocoagulation in the diagnosis of senile retinoschisis

In five of seven patients treated with argon laser photocoagulation, lesions were placed around retinal breaks and in the center of the breaks directly on exposed pigment epithelium. In a sixth patient, the lesions were placed through an area of atrophic detached retina on the bare pigment epithelium. In the last patient, the lesions were placed in the center of a large outer wall hole in an area of senile retinoschisis directly on bare pigment epithelium. The white reaction to photocoagulation, previously thought to differentiate between retinoschisis and retinal detachment, was produced in the eye with a rhegmatogenous retinal detachment. The white reaction also was produced in the center of retinal breaks where the photoreceptor layer was not in contact with the retinal pigment epithelium. Photocoagulation was not a definitive test, and must be evaluated with other clinical findings.

Retinal neovascularization in sickle cell retinopathy

Neovascularization of the retina occurs in several types of sickle cell hemoglobinopathies and is highly characteristic in appearance. It arises in the equatorial plane of the fundus following preliminary arteriolar occlusions and arteriolar-venular anastomoses. Neovascular sea fans arise at the interface of perfused and nonperfused portions of the retina, starting during the first decade of life and continuing for many years thereafter. Although some sea fans undergo spontaneous autoinfarction, most show progressive growth and constant intravitreal transudation of plasma components. Traction on the sea fans and the retina results in bleeding into the vitreous, retinal tears, and retinal detachment. Therapeutic intervention with a variety of coagulative techniques is feasible and is usually indicated whenever sea fans are discovered. All therapeutic modalities are capable of inducing significant complications. This is particularly true of argon laser photocoagulation when energy is concentrated into small areas (less than 200 mu) for short durations (less than 0.2 second). With appropriate precautions, photocoagulation results in a high rate of successful obliteration of neovascular tissue. Both vitrectomy and scleral buckling are valuable therapeutic procedures, but both have disproportionately high complication rates in eyes with the propensity for intravascular sickling of erythrocytes. Specific prophylactic measures are therefore indicated when these operative techniques are employed in patients with sickle cell diseases.

Fifteen year review of treated cases of retinal angiomatosis

This study describes the experience of the Wills Eye Hospital Retina Service in the treatment of 125 eyes with retinal angiomatosis, with follow-up ranging from 1 to 15 years. The results of several treatment modalities are compared. In lesions smaller than 2.5 DD, xenon arc photocoagulation, argon laser photocoagulation, and cryotherapy all appear to be effective in eradicating the tumor and salvaging useful visual acuity. For lesions larger than 2.5 DD, cryotherapy appeared to offer the best results. The advantages and disadvantages of the various treatment modalities are discussed.

[Clinical experience with the O'Malley LOG2 photocoagulator (author's transl)]

Clinical experience with a combination of the Clinitex photocoagulator and the Sadamel auxiliary apparatus (Fankhauser and Lotmar) is reported. This equipment proved to be very suitable for the photocoagulation therapy of degenerative and vascular processes and appeared to be only slightly inferior to the Zeiss apparatus. The coagulation at the posterior pole of the eyeball, within the distribution area of the temporal vessels, was somewhat more difficult than with the Zeiss apparatus: the longer coagulation times which are involved when smaller coagulation fields are used require more skill and experience. With coagulation outside the distribution area of the temporal vessels, on the other hand, no differences were observed in comparison with the Zeiss equipment. The Clinitex-Sadamel combination provides a practical apparatus for the photocoagulation therapy of retinal and choroidal disorders. In this combination the use of the O'Malley coagulator was extended to include photocoagulation, also through the three-reflector contact glass.

Cystoid maculopathy

Cystoid macular edema has become the most common and troublesome complication following cataract extraction. New techniques in cataract extraction, such as phacoemulsification and intraocular lens implants have not eliminated the problem, and careful studies are needed to determine whether they exacerbate or diminish it. Cystoid macular edema occurs in many areas of ophthalmology: cataract surgery, retinal surgery, uveitis, ocular tumors, diabetes, and arteriosclerotic vascular disease. Every ophthalmologist must, therefore, be thoroughly acquainted with methods for its recognition and with the inflammatory and vascular factors in its development. Prognosis and treatment are discussed, and the major gaps in our present understanding of pathogenesis are indicated, including the manner by which the vitreous changes following lens extraction lead to inflammation and the reason for the specific susceptibility of the mascular and disc capillaries to the inflammatory stimulus. Some hypotheses are presented.