A sufficiently large conjunctival sac and a deep fornix are essential conditions for placing a well-fitted eye prosthesis. In some patients, years of continuous damage due to inappropriate prosthesis or orbital implant exposure can result in fornix shrinkage and progressive contraction of the socket, which will lead to severely impaired function and poor cosmetic results that would negatively affect the psychological state of those patients. Moderate to severely contracted sockets are highly challenging to treat for ophthalmologic plastic surgeons; they take a long time to treat and have slow recovery and a low success rate.

Numerous procedures have been proposed for treating contracted sockets. Forniceal reconstruction includes grafts (skin, mucous membrane, hard palate, and dermis fat) [1,2,3,4,5] and flaps [6,7,8,9]. The disadvantages of these autologous tissues include the limited amount of available graft material, the need for a second surgical donor site, increased operating room time, and discomfort at donor sites.

To the best of our knowledge, allogeneic scleral grafts have been used for early orbital reconstruction [10]. The advantages of this tissue are ease of access, that is, close proximity to the eye, and suitable thickness of material to sufficiently cover the area of the defect. However, allogeneic scleral grafts are at risk of dissolving [11], and measures need to be taken to vascularise the grafts as early as possible. Several studies have verified the positive outcomes of low-level laser therapy (LLLT), including promotion of wound healing [12], reduction of inflammation [13], and increased blood flow to local blood vessels [14, 15].

In this study, allogeneic sclera was used as a graft to repair the contracted socket in all patients, some of whom were treated with LLLT after surgery. We aimed to observe and compare the conjunctival vascularisation and contraction that occurred in each group over a 6-month postoperative period.

This was a retrospective interventional case series containing data collected between April 2015 and April 2021, which included 39 patients with contracted sockets. According to the degree of conjunctival stenosis [16], all patients were diagnosed with grade 3 or 4 conjunctival stenosis and complained about the inability to retain prosthesis. There were 18 cases of simple conjunctival sac stenosis, 13 of anophthalmic socket stenosis, and eight of orbital implant exposure. The study included 26 men and 13 women, aged 13–61 years, with an average age of 39.15 years. There were 24 cases in the left eye and 15 cases in the right eye. All postoperative patients were required to do LLLT and the signing of the consent form,The LLLT required an additional 7 days and cost for treatment, so some patients refused.According to the whether the patients received the LLT after the surgery, the patients who received LLLT were included in the laser group (n = 18), and those who did not receive LLLT were included in the control group (n = 21). One week postoperatively, patients in the laser group began to receive LLLT, whereas those in the control group received no special treatment.

The use of allogeneic sclera material was approved by the Institutional Ethics Committee of Nanchang University and informed written consent was obtained from each patient recruited for the study in accordance with the Declaration of Helsinki. The allogeneic sclera was obtained from the eye bank of the Affiliated Eye Hospital of Nanchang University. Infectious disease indices of the donors were normal before surgery. After removing the cornea, the extrascleral tissue was removed, and the choroid was cleared. The sclera tissue was stored in a refrigerator with 95% ethanol and a low temperature of 4 °C. The sclera was removed and immersed in tobramycin saline solution for at least 2 h before the surgery to soften the sclera and was used for backup [17] (Fig. 1c).

Photographs of the surgical procedure. a The contracted socket; b the cavity provided for the allogeneic sclera implant; c the allogeneic sclera prepared; d interrupted suturing of the scleral patch graft and conjunctiva in situ around the cavity; e a scale measuring the maximum longitudinal diameters of the scleral patch graft; and (f) measurement of the maximum transverse diameters

In this study, all surgical procedures were performed under general anaesthesia by a single experienced surgeon in the same setting. The conjunctiva was opened horizontally in the centre of the socket and undermined using scissors until the superior and lower fornix relaxed or the scar tissue and contracted tissues were removed until there was no tension on the socket. The fornix was separated upward to grasp the depth, avoiding injury to the upper eyelid muscle, and downward to the lower orbital margin, creating a space at the centre of the socket and preparing the receptor bed for the graft (Fig. 1a, b). An appropriately sized plastic conformer was placed on the socket surface to observe whether the conjunctival sac was fully separated (the eyelid could naturally close as the standard). The size of the conjunctival defect was measured using a ruler and the corresponding full-thickness allogeneic scleral graft was placed in the socket over the exposed central area (Fig. 1d). The conjunctival and allogeneic scleras were sutured intermittently using 6–0 vicryl, and the edge of the allogeneic sclera was placed under the residual conjunctival surface. If the patient with conjunctival sac stenosis has no eyeball and eye socket is stable, hydroxyapatite (HA) can be implanted simultaneously. HA is a commonly used filling material and compensate orbital volume deficiency, reduce the risk of socket contraction complication, relatively light weight implants avoiding pressure over the lower lids, decreasing the risk of lower eyelid sag and upper lid sulcus deformity. The porous structure of HA is beneficial for the growth of vascular fibers and rapid vascularization is the basis of successful orbital implantation. The residual conjunctiva and fascia at the site of the plant bed provided vital vascular support to the scleral patch and anterior implant. Postoperatively, a snugly fitting conformer with multiple holes was placed in the reconstructed socket to maintain adequate pressure on the graft and the area of the fornices. The patient was bandaged for 48 h and instructed to apply ice packs for the first 24 h postoperatively and local antibiotic eye drops were used for 2 weeks.

LLLT equipment (JAM2-II type; Jiangxi Teli Anesthesia & Respiration Equipment Co., Ltd.) with a wavelength of 650 nm, 10 (0–20) MW power, and a dosage of 3.8 J/cm2 was used. During application, the pen remained perpendicular to the edge of the junction of the conjunctiva and allogeneic sclera, with a distance of 1 cm between the irradiation surface, a spot diameter of 10 mm, and a laser power density of 12.7 mW/cm2. Irradiation was performed once daily for 5 min over 7 days; the plastic conformer was removed before the treatment and then put on after treatment.

All postoperative data are presented at the 180-day (6-month) follow-up visit. Data were also collected immediately after the surgery and at 1, 3, and 6 months using an objective scale measuring the maximum transverse and longitudinal diameters (unit: mm) of the non-vascularised allogeneic sclera. The area of the non-vascularised graft (transverse diameter × longitudinal diameter) was calculated (Fig. 1e, f), and the speed of conjunctival vascularisation was observed (Figs. 2 and 3). Simultaneously, the fornices were measured by placing the scale vertically in the socket and asking the patient to look inferiorly for the superior fornix and superiorly for the inferior fornix. The distance between the fornix coinciding with the lid margin was recorded as the depth of the inferior fornix (IF) and superior fornix (SF) (Fig. 4), IF added to SF was the depth of the fornices. All measurements were performed by one of the authors who performed contrast-enhanced magnetic resonance imaging (MRI) 6 months postoperatively. Subjective evaluation of the presence of secretions, granulomas, or foul odours was also performed. A good outcome was defined as no prosthesis prolapse, and a poor outcome was defined as no improvement in the contracted socket that required further surgery, the inability to fit a prosthesis, or prosthesis prolapse.

Photographs of case 1 from the laser group. a Patient with contracted socket combined orbital implant exposure; b preoperative contrast-enhanced magnetic resonance imaging (MRI): the unvascularised portion of the hydroxyapatite (HA) (red arrow); c anterior segment photograph: 2 weeks after the surgery; d one month after the surgery: the residual conjunctiva grows to the surface of the allogeneic sclera and has passed the edge of the original junction (red arrow) and neovascularisation can be observed (blue arrow); e six weeks after the surgery; f three months after the surgery; and (g) postoperative 6-month contrast-enhanced MRI: allogeneic sclera (red arrow) and HA is vascularised; (h) the conjunctival sac is completely vascularised and deep fornix is formed after low-level laser therapy; and (i) post-treatment photograph and prosthesis fitting

Photographs of case 2 from the laser group. a Patient with contracted and low-capacity anophthalmic socket; b one week after the surgery (hydroxyapatite implanted combined with conjunctival sac forming with allogeneic sclera covering); c one month after the surgery; and (d) prosthesis fitting

The fornices are measured by placing the scale vertically in the socket and asking the patient to look inferiorly for superior fornix and superiorly for inferior fornix. a Ruler positioned to obtain measurements of the inferior and (b) upper fornices