Case of the Month

Edited by Robert N. Johnson, MD

Figures 1 and 2: Color photographs of the right and left eye. Note the numerous drusen, larger centrally, but extending throughout the posterior pole of both eyes.

Case History

A 51-year-old Caucasian man with a history of hypertension presents with visual distortion and smudged appearing central vision of a few months duration in the right eye.

On examination, visual acuity was 20/32 in both eyes.  The anterior segment examination was unremarkable. Dilated examination in both eyes revealed multiple soft cuticular drusen. The right eye also had a flat choroidal nevus in the superior macula (Figures 1-2). Ocular coherence tomography displayed saw tooth-like appearing drusen of varying sizes in both eyes (Figures 3 and 4). There was evidence of subretinal fluid in the right eye (Figure 4). Fluorescein angiography revealed punctate areas of hyperfluorescence of the drusen (Figure 5). Fundus autofluoresence displayed hypoautofluoresence of the drusen.

Figures 3 and 4: SD-OCT scans through the right (top) and left (bottom) macula. Note the variably sized elevations between the RPE and Inner layer of Bruchs membrane. See Figures 2-Inset and Figures 4-Inset below for corresponding color and enlarged detail of scan through left eye.

Figure 2 and 4 Detail: Detail view of left macula with line depicting area of SD-OCT scan.

Figure 5: Fluorescein angiogram of the right eye. Note the extensive areas of early hyperfluorescence producing a 'stars-in-the-sky' appearance.

Differential Diagnosis

Age related macular degeneration, adult vitelliform foveomacular dystrophy, basal laminar drusen, Best vitelliform dystrophy, pattern dystrophy, familial drusen, fundus albipunctatus

Additional History and Diagnosis

The patient had no family history of macular degeneration. Because there was no evidence of active choroidal neovascularization on fluorescein angiogram, we elected to monitor his condition. He was seen two months later for follow up with no interval change in his vision or in the quantity of subretinal fluid. In the event of an increase in subretinal fluid or presence of choroidal neovascularization, anti-vascular endothelial growth factor injections will be initiated.

Discussion

Basal laminar drusen (cuticular drusen) is a rare condition first described by Donald Gass in 1977.¹ It is thought to represent nodular thickening of the basement membrane of the retinal pigment epithelium (RPE) resulting in small round drusen, 25 to 75 microns in size, which may appear in early adulthood.² They tend to be raised, discrete, yellow, round subretinal deposits which are randomly scattered in the macula.  Histopathologically they are a focus of thickened RPE basement membrane³, with elevation between the RPE-basal laminar band.⁶

Later in life drusen may become more numerous and at times form a cluster of 15 to 20. These basal laminar drusen may predispose patients to the development of loss of central vision from a vitelliform exudative macular detachment.³ Additionally, patients older than 50 years of age may develop exudative drusen in the central macula and or experience visual loss due to yellow serous exudative detachment. Most patients to date have no family members with signs of disease.⁵

Basal laminar drusen are best visualized with fluorescein angiography which reveals “stars-in-the-sky” or “milky-way” configuration in early phase.^1.3.6 On fundus autofluorescence these drusen have a hypoautofluorescent center surrounded by a ring of increased autofluorescence.^2,6 Recently, Balaratnasingam and coworkers, evaluated a large series of patients with cuticular drusen. OCT findings disclosed three types of drusen configurations: Type 1 with a very shallow elevation of the RPE-basal laminar band, Type 2 pattern with a triangular elevation, and Type 3 with a broad mound-shaped elevation of the RPE-basal laminar band.⁶ Our patient’s images demonstrate these findings nicely (Figure 4-detail).

It is important to distinguish basal laminar drusen from age related macular degeneration as the treatment approaches and prognoses differ.6 Although visual symptoms may occur at a younger age in basal laminar drusen, the visual loss tends to occur more slowly, the incidence of geographic atrophy is higher, and the incidence of choroidal neovascularization and large exudative detachment of RPE is lower. The prognosis for retaining useful central vision is better than in age-related macular degeneration.^2,6

Patients who experience serous detachment tend to maintain good visual acuity of 20/30 to 20/50 with stability of the subretinal fluid. In some instances the fluid may resolve spontaneously with restoration of good vision. In others, however, poor vision may develop from geographic atrophy, choroidal neovascularization, or serous hemorrhagic disciform detachment.^2.5.6 Acquired vitelliform lesions occur in about 1/4 patients and are more common in those over age 60 (1/3 of patients).⁶

Treatment is not necessary unless the visual decline is significant, or if there is evidence of choroidal neovascularization. Choroidal neovascularization occurs in about 12% of eyes.⁶ There are no formal guidelines for treatment. Case reports have previously demonstrated successful use of anti vascular endothelial growth factor and photodynamic therapy.^7,8

References

1. Gass JDM. Stereoscopic atlas of macular diseases; diagnosis and treatment, 2nd ed. St. Louis:
   CV Mosby; 1977. p. 46.
2. Agarwal A. Basal laminar drusen and macular degeneration. In: Agarwal, A. Gass’ Atlas of Macular Diseases. Fifth ed. Elsevier:132-135.
3. Gass JDM, Jallow S, Davis B. Adult vitelliform macular detachment occurring in patients with basal laminar drusen. Am J Ophthalmol 1985;99:445–59.
4. Kenyon KR, Maumenee AE, Ryan SJ, et al. Diffuse drusen and associated complications. Am J Ophthalmol 1985;100:119–28.
5. Lerche W. Pigmentepithelveränderungen bei Drusen im Maculabereich. Ber Dtsch Ophthalmol Ges 1973;73:439–46.
6. Balaratnasingam C, Cherepanoff S, Doz-Marco R, et al: Cuticular Drusen. Clinical phenotypes and natural history defined using multimodal imaging. Ophthalmology 2018;125:100-118.
7. Morillo MJ, Gonzalez-Escobar AB, Baquero I, et al. Bevacizumab treatment for acquired vitelliform detachment in patient with cuticular drusen. Arch Soc Esp Oftalmol 2014 Apr;89(4):165-9.
8. Guigui B, Martinet V, Leveziel N, et al. Photodynamic therapy for choroidal neovascularization secondary to basal laminar drusen. Eye 2009 Oct;23:2115-2118.