Recent advances in the treatment of senile disciform macular degeneration by photocoagulation.

In senile disciform macular degeneration the retina and pigment epithelium are elevated by serous fluid, which arises from subpigment epithelial fibrovascular tissue originating from the choroid. Disciform macular degeneration was described in the igth century (Oeller, I893) and yet by 1939, when the "Text-Book of Ophthalmology" was being written, Duke-Elder (I940) could find only I30 cases in the literature, and it appeared at that time to be an uncommon disease. During the last decade several factors have stimulated increasing interest in the disease. With increased longevity, disciform macular disease is becoming more prevalent and senile macular degeneration is now recognized as the most common cause of blindness in England and Wales (Sorsby, I966). Since the advent of fluorescein fundus angiography, the morphology of the lesion may be studied during life (Gass, I 967) and in addition photocoagulation has provided a means of treating the disease. Though drusen in the posterior fundus and senile disciform degeneration were described many years ago (Donders, I855; Oeller, I893, I 905; Junius and Kuhnt, I926), it was not until I940 that it was recognized that drusen and changes in the pigment epithelium were a predisposing cause of senile disciform macular degeneration (Gifford and Cushman, 1940). It is now known that disciform macular degeneration is preceded by age-related changes in the posterior fundus. These changes are clinically recognizable as drusen and irregular pigmentation of the pigment epithelium. Drusen have been recorded in the third decade of life in families with dominantly inherited disease by Pearce (I968) and occasionally as early as 12 years of age by Deutman and Jansen (I970), though few patients develop drusen until late in life. Gass (1973) recorded an increase in the number and size of drusen with advancing age. The pathogenesis of age-related epithelial change and drusen is uncertain. With increasing age, Bruch's membrane becomes thicker (Hogan i967; Hogan, Alvarado, and Weddell, I971). Collagen fibres are abnormally electron dense and irregular banded fibres appear in the inner collagen layer. Long dense osmiophilic fibres have also been seen and probably arise from collagen. The elastic zone becomes basophilic with increasing density of the fibres and deposition of needle-like crystals and calcium in the elastic fibres (Hogan and others, I971). Accompanying the fibre changes there is deposition of PASpositive granular vesicular and filamentary material at first in the matrix of the inner collagen layer and later in the elastic layer. This material resembles amorphous vesicles