bubble_chart Overview

This condition is also known as senile retinoschisis, but it can occur in young individuals after the age of 20, making the term "senile" inaccurate. It is a common condition among people over 40 years old. However, it is rarely reported in Chinese and Japanese literature, possibly due to racial differences. Over 80% of cases involve both eyes, with symmetrical presentation and no gender differences. Patients often seek medical attention due to symptoms such as flashes of light or floaters, otherwise, it is usually discovered incidentally during a fundus examination for other reasons.

bubble_chart Pathogenesis

The basis of this disease is peripheral micro-cystoid degeneration. Near the ora serrata, there are small vesicles known as Blessing-Iwanoff cavities in the outer plexiform layer of the retina, as observed in pathological specimens. These vesicles appear as grayish-white turbid spots under binocular indirect ophthalmoscopy or three-mirror examination, slowly expanding and merging with age, leading to a split between the outer and inner nuclear layers, forming large cystic cavities. The inner wall (inner layer) of the cystic cavity becomes thinner due to the degeneration and disappearance of neural components, eventually leaving only the inner limiting membrane and glial cells; the outer wall (outer layer) retains the photoreceptor layer and the pigment epithelial layer. As the disease progresses, the cystic cavities continue to expand, with neural pillars primarily composed of Müller cells remaining between the cavities, serving as columns connecting the inner and outer walls. After the neural pillars rupture, the stumps attach to the inner surface of the inner wall. Within the cystic cavity between the inner and outer walls, there is a transparent mucus retention. The mucus is composed of mucopolysaccharide acid.

bubble_chart Clinical Manifestations

Under the ophthalmoscope, the schisis is located in the peripheral part of the fundus. The inner wall of the hemispherical elevation is thin and transparent, so the surface appears smooth and silky with a watered silk appearance. The anterior edge of the schisis connects to the ora serrata, and the posterior edge has a clear, steep boundary. The retinal vessels attached to the inner wall can be seen as projections (vessel shadows) on the outer wall. Changes such as whitening of retinal vessels and parallel sheathing are also commonly observed. Bright white snowflake-like spots (snowflakes) can be seen throughout the inner surface of the inner wall, which are the attachment points of the aforementioned columnar strands. Additionally, careful observation of the inner surface of the inner wall with a slit-lamp microscope reveals fine hemispherical depressions, resembling the beaten metal appearance, which are traces of previous microcystic degeneration.

The photoreceptor layer remains attached to the pigment epithelium, forming the outer wall of the schisis, which is difficult to see under the ophthalmoscope. However, by gently pressing the sclera with a scleral depressor, the outer wall at the pressed area appears white and cloudy, known as "white with pressure."

Small round holes can occur in either the inner or outer wall of the schisis. Holes in the inner wall are usually small and located near the ora serrata, while those in the outer wall are larger and more posterior.

At the junction between the schisis edge and the healthy retina, a so-called demarcation line with pigment may occasionally be present.

This condition occurs in emmetropic or hyperopic eyes and is rarely associated with myopia. The vitreous is usually unaffected. 80% of cases involve both eyes symmetrically. The most common location is the inferotemporal periphery, followed by the superotemporal periphery. Nasal involvement is very rare.

Since the lesion is confined to the periphery, patients are often unaware of it. Only when the schisis extends posteriorly beyond the equator, especially when the photoreceptor layer separates from the bipolar cell layer and neurons are severed, can corresponding absolute neurological deficits be detected. As long as the lesion does not involve the macula, good central vision can be maintained. However, in this disease, if retinal detachment does not occur, extension near the macula is extremely rare.

bubble_chart Treatment Measures

Regarding the question of whether this disease requires treatment, scholars have differing opinions. Based on various perspectives and the author's experience, the following recommendations are proposed:

(1) If there is only an inner wall hole, and long-term follow-up visual field tests show no significant expansion of the defect, no treatment is necessary.

(2) If the splitting range extends backward to or beyond the equator, photocoagulation or cryocoagulation of the entire lesion area is recommended. Alternatively, photocoagulation can be performed on the healthy retina adjacent to the posterior edge of the lesion area.

(3) When there are holes in both the inner and outer walls, photocoagulation or cryocoagulation should be applied to the edges of the holes to seal them. Alternatively, only the outer wall hole may be sealed, leaving the inner wall hole untreated.

(4) If retinal detachment has occurred, this is a significant indication for surgery. Perform scleral buckling and seal the outer layer hole.

bubble_chart Prognosis

This disease is almost non-progressive, and even if it progresses, it is very slow. Therefore, it is a self-limiting benign condition. However, when holes form in both the inner and outer walls of the split, it is also prone to causing retinal detachment. According to literature, the probability of retinal detachment occurring when there are holes in both the inner and outer walls is 77-96%, accounting for 2.1%-3.2% of the causes of retinal detachment due to holes. From this perspective, it cannot be said that there is no risk. However, according to Byer's estimation, cases with holes in both the inner and outer walls account for only 1.4% of all acquired retinal splits.

bubble_chart Differentiation

Based on the characteristic changes of the clinical phenomena described above, a diagnosis can be made. Detailed examination of the fundus using binocular indirect ophthalmoscopy and slit-lamp microscopy can help differentiate this condition from rhegmatogenous retinal detachment and congenital retinoschisis.

The key points for differentiation from primary retinal detachment are shown in Table 1.

Table 1 Differentiation between acquired retinoschisis and primary retinal detachment.

	Acquired Retinoschisis	Primary Retinal Detachment
Bilateral Incidence	Over 80%	Around 15%
Location	Mostly in the lower temporal area	Variable
Disease Progression	Non-progressive or extremely slow	Rapid or relatively fast
Holes	Occur in the outer wall of the schisis, mostly small round holes without operculum	Full-thickness holes vary in shape, horseshoe-shaped holes are common, often with operculum
Vitreous Degeneration	Not obvious	Obvious (liquefaction, detachment, opacity, membrane formation)
Refractive Error	No significant change or farsightedness	Myopia, especially high myopia

Differentiation from congenital retinoschisis, although there are differences in fundus manifestations, is mainly based on the age of onset. Congenital cases are present from birth and are usually discovered in children around 10 years old, with a family history and limited to males, as they are all accompanied by macular schisis, leading to severe visual impairment. Acquired cases are seen in adults over 20 years old, more commonly in those over 40. There is no family history, and it can occur in both sexes. The macula is generally not involved, and good central vision is often maintained.