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. 2026 Aug 4;21(8):e0354967. doi: 10.1371/journal.pone.0354967

Clinical course and outcomes of corneal blood staining in open-globe injury: Eye Injury Vitrectomy Study

Bingjie Wang 1,2, Kang Feng 1, Yao Lu 1, Huijin Chen 1, Liang Han 1, Aihua Ding 1, Haikun Wang 1, Shaofeng Gu 1, Zhizhong Ma 1,*
Editor: Ugochukwu Anthony Eze3
PMCID: PMC13436741  PMID: 42550828

Abstract

Purpose

To describe the clinical course and outcomes of corneal blood staining in open-globe injuries (OGIs) after vitrectomy without routine immediate allograft penetrating keratoplasty (PKP).

Methods

This study included 42 eyes of 42 patients with corneal blood staining secondary to OGIs. Clinical data were retrospectively collected from the Eye Injury Vitrectomy Study (EIVS). All eyes underwent anterior chamber washout at the start of pars plana vitrectomy (PPV). When visualization remained inadequate, temporary keratoprosthesis (TKP)-assisted PPV was performed, followed by replacement of the trephined autologous cornea (TKP + PPV + RTC). Postoperative outcomes, including corneal transparency, best-corrected visual acuity (BCVA), intraocular pressure (IOP), and need for subsequent PKP, were assessed.

Results

Median age was 36.5 years; globe rupture accounted for 95.2%. Preoperative hypotony (IOP ≤ 10 mmHg) was present in 90.5%, with severe posterior segment injury in all eyes. Eight eyes achieved sufficient corneal clarity after washout alone; the remaining 34 required TKP + PPV + RTC. During follow-up, varying degrees of spontaneous clearance occurred in most eyes, forming a peripheral “window” that enabled fundus assessment. At the final follow-up, BCVA improved from median 4.00 logMAR preoperatively to 2.80 logMAR (p = 0.002), and median IOP rose from 5.00 to 10.00 mmHg (p = 0.002). Five eyes developed phthisis bulbi, four eyes achieved complete silicone oil removal, and only 1 eye underwent allograft PKP.

Conclusions

The strategy of anterior chamber washout first, followed by TKP + PPV + RTC when necessary, provides timely posterior segment access while preserving the globe and conserving corneal tissue in severe OGIs complicated by corneal blood staining. These findings support selective, rather than routine, PKP during follow-up.

Introduction

Open-globe injuries (OGIs) are ocular injuries associated with the worst visual outcomes and may result in monocular or bilateral blindness, particularly in eyes with globe rupture [1,2]. Adequate corneal transparency is essential for visualization of posterior segment pathology. In severe ocular trauma, however, corneal transparency may be compromised, limiting clinical assessment and impeding surgical repair.

Among trauma-related corneal opacities, corneal blood staining is one of the most challenging conditions. It is characterized by deposition of hemoglobin and its breakdown products within the corneal stroma [3], most commonly following prolonged hyphema and elevation of intraocular pressure (IOP) [4,5], but it has also been reported in eyes with low IOP [6,7]. Disruption of endothelial function, stromal impregnation by erythrocyte derivatives, and impaired metabolic clearance contribute to its development [8].

In eyes with corneal blood staining requiring pars plana vitrectomy (PPV), a temporary keratoprosthesis (TKP) is commonly used to facilitate posterior segment visualization [9]. This approach, however, necessitates donor tissue for subsequent allograft penetrating keratoplasty (PKP) and is associated with risks of graft rejection and infection related to long-term immunosuppression [10]. Furthermore, given the poor prognosis in eyes with extensive posterior segment damage, the indication for immediate PKP may be uncertain. Although endoscopy-assisted vitrectomy has been proposed as an alternative, its adoption is limited by low image resolution, restricted field of view, specialized equipment requirements, and a steep learning curve [11–13].

In this study, we evaluated a modified corneal conservative surgical strategy for OGIs complicated by corneal blood staining, and analyzed anatomical and functional outcomes, as well as the evolution of corneal blood staining.

Methods

Human ethics and consent to participate declarations

This study was approved by the Institutional Review Board of Peking University Third Hospital Medical Science Research Ethics Committee (Ethics No. IRB00006761-2012060) and was conducted in accordance with the Declaration of Helsinki. Clinical data were collected from the Eye Injury Vitrectomy Study (EIVS). The trial was registered with the Chinese Clinical Trial Registry (ChiCTR; Number: ChiCTR-OCH-08000199) on November 28, 2008. Written informed consent was obtained from all participants at the time of enrollment in the EIVS, including consent for the use of non-personally identifiable medical records for future research. For participants younger than 18 years of age, written informed consent was obtained from their parents or legal guardians. The present study represents a retrospective analysis of EIVS data from Peking University Third Hospital between June 2012 and June 2025. As defined by the EIVS database, the general inclusion criteria were patients who suffered from severe eye injury and were treated with vitreoretinal surgery, enucleation, or evisceration [14]. Throughout data collection and analysis, the investigators had access only to fully anonymized data and no personal identifiable information. Given the retrospective nature of this study and the use of anonymized data, the ethics committee waived the requirement for additional informed consent.

Participants and clinical evaluation

Patients with OGIs complicated by corneal blood staining were included. Exclusion criteria were endophthalmitis, pre-existing ocular pathology, incomplete clinical or photographic records, follow-up < 12 months, or enucleation/evisceration within 12 months (S1 File).

Preoperative data collected included age, sex, ocular history, best-corrected visual acuity (BCVA), IOP, slit-lamp photographs, and anterior segment optical coherence tomography (AS-OCT). BCVA was measured using a standard vision chart and converted into logarithm of the minimum angle of resolution (logMAR). For statistical consistency, counting fingers, hand motion, light perception, and no light perception (NLP) were converted to 1.87, 2.30, 2.80, and 4.00 logMAR, respectively. IOP was measured using a rebound tonometer (iCare TA01i, Icare Finland Oy, Helsinki, Finland). AS-OCT (Wavelength nanometer, Tomey CASIA2, Nagoya, Japan) was performed by trained clinicians (AD, HW, and SG), with serial scans were obtained from same corneal regions whenever possible, using anatomical landmarks and previous scan locations as references.

All patients underwent anterior chamber washout at the start of the initial PPV. Sufficient clarity for PPV after washout was defined as intraoperative corneal clarity that allowed the surgeon to identify major posterior segment structures and proceed safely without TKP. When safe visualization could not be achieved, TKP-assisted PPV was performed, followed by replacement of the trephined autologous cornea (TKP + PPV + RTC). The surgical procedure for TKP + PPV + RTC was described previously [15]. Follow-up duration varied among patients. BCVA, IOP, and slit-lamp photographs were recorded at each visit. Additional treatments were provided as clinically indicated.

Postoperative corneal outcomes were categorized as complete clearing, partial clearing, or persistent opacity. Complete clearing was defined as disappearance of opacity attributable to corneal blood staining during follow-up, although other corneal changes such as scarring or band keratopathy could still be present. Partial clearing was defined as a recognizable decrease in corneal blood staining compared with baseline, with formation of a clear corneal area sufficient for clinical posterior segment assessment. Persistent opacity was defined as residual opacity attributable to corneal blood staining with little or no regression compared with baseline, continuing to limit corneal transparency or fundus visualization. Serial slit-lamp photographs, fundus photographs when available, and clinical records were independently reviewed by two ophthalmologists (KF and LH) to classify the corneal outcomes. Disagreements were resolved by a senior ophthalmologist (ZM).

Statistical analyses

Data were analyzed using SPSS software (version 26.0, IBM Corp., Armonk, NY, USA) and GraphPad Prism 8 (GraphPad Software, San Diego, CA, USA). Descriptive statistics were reported as median (interquartile range, IQR) for non-normally distributed variables or mean ± standard deviation for normally distributed variables. Preoperative and postoperative parameters were compared using the Wilcoxon matched-pairs signed rank test. A p-value of < 0.05 was considered statistically significant.

Result

A total of 3,152 eyes in the EIVS database were screened, including 1,920 eyes with open-globe injuries. Among them, 157 eyes had documented corneal blood staining. After excluding 115 eyes because of endophthalmitis, pre-existing ocular diseases, incomplete clinical or photographic records, follow-up shorter than 12 months, or enucleation/evisceration within 12 months; 42 eyes (42 patients, 37 patients [88.1%] were male; 16 right eyes) were included in the final analysis (S1 File). The median age was 36.5 years (range, 3–61 years). The mechanism of injury was globe rupture in 40 eyes (95.2%), penetrating injury in 1 eye (2.4%), and intraocular foreign body (IOFB) in 1 eye (2.4%). The median interval from trauma to surgery was 21.5 days (IQR, 15.0–28.5 days).

Preoperative ocular hypotony (intraocular pressure [IOP] ≤10 mmHg) was present in 38 eyes (90.5%). Severe posterior segment injury was common: choroidal detachment occurred in 40 eyes, retinal detachment in 37 eyes, and no identifiable retinal tissue was noted in 5 eyes. All eyes received intraocular tamponade with silicone oil (n = 40) or long-acting gas (n = 2). The median follow-up duration was 36 months (IQR, 23–42 months; range, 12–60 months). During follow-up, most eyes required additional silicone oil procedures (e.g., oil refill, partial removal, or removal with re-tamponade), and complete silicone oil removal was achieved in only 4 eyes by the final visit.

After anterior chamber washout, adequate corneal clarity to proceed with PPV was achieved in 8 eyes, whereas the remaining 34 eyes required TKP + PPV + RTC. During follow-up, clearing of cornea blood staining was observed 35/42 eyes. In the anterior chamber washout only group, complete clearing occurred in 4 eyes and partial clearing in 4 eyes. In the TKP + PPV + RTC group, complete clearing occurred in 9 eyes, partial clearing in 18 eyes, and persistent opacity in 7 eyes. The first documented timing of corneal clearing is summarized in S2 File. Complete or partial clearing formed a peripheral “window” that permitted fundus assessment (Fig 1a–1e). At the final follow-up, persistent central opacity or scarring was observed in 17 of 42 eyes, including band keratopathy (9/42), central corneal scarring, and residual blood staining (Fig 1). Fig 2 presents serial AS-OCT images of a representative case from the complete clearing group managed with anterior chamber washout only, showing gradual clearing of corneal blood staining in this eye.

Fig 1. Anterior segment photographs of corneal blood staining before and after clearing, with corresponding fundus views.

Fig 1

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This series focuses on corneal changes and the possibility for fundus assessment; concomitant intraocular comorbidities were not considered. Each case is presented as paired panels, with the corresponding fundus image displayed in the upper right corner (a–e). (A, a) Immediate postoperative and postoperative month 6 (history of radial keratotomy). Vascularization at periphery cornea can be seen. (B, b) Postoperative months 2 and 17. (C, c) Intraoperative and postoperative month 12. (D, d) Postoperative months 6 and 24. (E, e) Intraoperative and postoperative month 48. (F, f) Preoperative and postoperative month 7, showing band keratopathy. (G, g) Preoperative and postoperative day 1. (H, h) Immediate postoperative and postoperative month 24, showing central corneal opacity. (I, i) Postoperative day 1 and postoperative month 15. (J, j) Preoperative and postoperative month 4.

Fig 2. Slit-lamp photographs and AS-OCT demonstrating complete resolution of corneal blood staining.

Fig 2

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(A, D) Postoperative month 4; (B, E) postoperative month 10; (C, F) postoperative month 16.

Preoperatively, 28 eyes (66.7%) had NLP, which decreased to 12 eyes (28.6%) after surgery. At the final follow-up, phthisis bulbi developed in 5 eyes. Baseline characteristics and perioperative outcomes are summarized in Table 1. Only one eye underwent delayed allograft PKP. This was a gas-tamponaded eye in a 46-year-old man with traumatic aniridia, aphakia after prior lens extraction in local hospital, vitreous hemorrhage, and post-traumatic secondary glaucoma. Although preoperative B-scan suggested choroidal detachment, this finding were not confirmed intraoperatively, and laser photocoagulation was applied around the retinal break after retinal attachment. The RTC gradually clearing, and BCVA reached 0.3 logMAR at 14 months after the initial surgery, with well-controlled IOP, indicating favorable visual potential and a relatively stable posterior segment. Allograft PKP combined with scleral-fixated IOL implantation was therefore performed for optical rehabilitation and aphakia correction. Early post-PKP follow-up was available, but the patient was subsequently lost to follow-up. When he returned 3 years after PKP, the eye had progressed to NLP due to glaucoma, with epithelial edema but relatively preserved stromal clarity in corneal graft.

Table 1. Patient demographics, preoperative/postoperative ocular findings.

Patients Enrolled (n = 42)
Age, median (IQR) (years) 36.5 (25.8–49.3)
Right eye, n (%) 16 (38.1)
Male, n (%) 37 (88.1)
Surgery time interval, median (IQR) (days) 21.5 (15.0–28.5)
Open globe injury, n (%) 42 (100)
 Rupture 40 (95.2)
 Penetrating 1 (2.4)
 Intraocular foreign bodies (IOFB) 1 (2.4)
Hypotony, n (%) 38 (90.5)
Retinal and choroidal condition, n (%)
 Choroidal detachment 40 (95.2)
 Retinal detachment 37 (88.1)
 No retina detected 5 (11.9)
Intraocular tamponade, n (%) 42 (100)
 Silicone oil 40 (95.2)
 Long-acting gas 2 (4.8)
 Balanced salt solution 0 (0)
Cornea management, n (%)
 TKP + PPV + RTC 34 (81.0)
 After anterior chamber washout, corneal transparency was sufficient for PPV 8 (19.0)
Follow-up duration, median (IQR) (months) 36 (23–42)
NLP preoperatively, n (%) 28 (66.7)
NLP postoperatively, n (%) 12 (28.6)
Phthisis bulbi at the final follow-up, n (%) 5 (11.9)
SOR at the final follow-up, n (%) 4/40 (10)
Received PKP at the final follow-up, n (%) 1 (2.4), tamponade with gas
Cornea outcome, n (%)
 TKP + PPV + RTC
  Complete clearing 9/34 (26.5)
  Partial clearing 18/34 (52.9)
  Persistent opacity 7/34 (20.6)
 Anterior chamber washout only
  Complete clearing 4/8 (50)
  Partial clearing 4/8 (50)
  Persistent opacity 0/8 (0)
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Median BCVA improved from 4.00 logMAR preoperatively (IQR, 2.80–4.00) to 3.40 logMAR on day 1 (IQR, 2.80–4.00; p = 0.016) and 2.80 logMAR on day 7 (IQR, 2.80–4.00; p = 0.002), as well as at the final visit (median, 2.80 logMAR; IQR, 2.30–4.00; p = 0.002). BCVA showed no significant difference between day 7 and the final visit (p = 0.344) (Fig 3A).

Fig 3. Changes in BCVA and IOP preoperative/postoperative.

Fig 3

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(A) BCVA demonstrated significant improvement at D1, D7 and the final visit comparing with preoperative. No significant improvement was observed at final visit when compared with D7 (n = 42). (B) IOP significantly increased at D1, and dropped at D7 to preoperative level. At final visit, IOP showed significant increase compared with pre-op, this process includes multiple silicone oil refilling in some cases. Median with IQR, Wilcoxon matched-pairs signed-rank test; *p < 0.05, **p < 0.01. Abbreviations: Pre-op, preoperative; D1, postoperative day 1; D7, postoperative day 7.

Median IOP increased from 5.00 mmHg preoperatively (IQR, 4.00–8.75) to 8.95 mmHg on day 1 (IQR, 5.50–10.00; p = 0.019), measured 7.00 mmHg on day 7 (IQR, 6.25–10.00, p = 0.401), and reached 10.00 mmHg at the final visit (IQR, 5.50–11.00, p = 0.002) (Fig 3B).

Discussion

Management of corneal blood staining in the setting of complex ocular trauma remains challenging. In this series, we applied a modified approach (anterior chamber washout first, then TKP + PPV + RTC if needed) instead of performing immediate allogeneic PKP. A key observation was that corneal blood staining frequently showed spontaneous partial-to-complete resolution after surgery, often providing a peripheral “window” that permitted postoperative fundus assessment (Fig 1a–1e). For eyes with corneal opacity that limited direct visualization, including during the early postoperative period (e.g., at 1 week), posterior segment assessment was performed using B-scan ultrasonography, visual function examinations, and IOP measurement. The decision to perform subsequent PKP is strictly based on a comprehensive evaluation of both visual function and the anatomical viability of the injured eye. Only one eye ultimately underwent PKP. These findings support a conservative corneal strategy in eyes with limited visual potential and high graft-risk profiles. Conventionally, surgery has relied on immediate allogeneic PKP following TKP-assisted PPV. However, this strategy exposes the corneal graft to pathophysiologic stressors that are common in severely injured eyes, and may increase exposure to prolonged postoperative corticosteroid or immunosuppressive therapy as well as the risk of graft rejection in eyes with limited visual potential.

OGIs often leads to persistent hypotony and silicone-oil sustained [15,16]. In OGIs, hypotony can arise from direct ciliary body injury, cyclodialysis, ischemia and/or membrane formation of ciliary body, leading to reduced aqueous humor production and/or increased outflow through the suprachoroidal space [17–19]. Under these conditions, impaired aqueous circulation compromises corneal metabolic support, while sustained contact between silicone oil and the corneal endothelium accelerates endothelial dysfunction [20]. Together, these factors increase the risk of graft decompensation and failure after PKP [21].

Inflammation is another problem. Eyes with OGIs are commonly in an active inflammatory state at the time of PPV, which is a well-established independent risk factor for graft failure [22]. Inflammation induces upregulation of major histocompatibility complex (MHC) class I and class II antigen expression [23] and promotes vascular endothelial growth factor production, thereby facilitating graft rejection and corneal neovascularization [24]. Consistent with these mechanisms, Williams et al. showed that past ocular inflammation increased the risk of graft failure by 4.40-fold, while active inflammation increased the risk to 9.6-fold [25]. Accordingly, delaying PKP until inflammation has stabilized may reduce the risk of failure. The clinical importance of PKP timing has been supported by prior studies; for example, Roters et al. reported a significantly lower rate of graft failure when PKP was performed after 8 weeks of trauma [21]. Although delaying surgery may allow neovascularization to develop, as shown in Fig 1a, resulting in a vascularized graft bed. This trade-off may be acceptable, as the associated risk (odds ratio, 2.74 [25]) is substantially lower than that posed by active inflammation.

Importantly, the overall prognosis of OGIs is often poor [15]. All eyes in our series had severe vision-threatening pathology, including choroidal detachment, retinal detachment, or retinal tissue loss. Twenty-eight eyes presented with no light perception (NLP), and 12 remained NLP after surgery. During follow-up, 11.9% progressed to phthisis, indicating irreversible anatomical failure. In addition, silicone oil removal, which is critical for graft survival, was achieved in only 10% of our cases. Under these conditions, corneal transplantation may offer limited functional benefit in many eyes. Other global assessment of ocular viability—such as IOP trends, residual light perception, and B scan findings—may be more informative in guiding management decisions [26–28]. Consistent with this reality, only one eye underwent PKP in our study, suggesting that most patients were poor candidates for primary keratoplasty; for these individuals, TKP + PPV + RTC represents a more cost-effective and practical strategy. This selective approach is also vital when considering the critical global shortage of donor tissue, where only one cornea is available for every 70 patients in need [29].

The natural course of corneal blood staining further supports a conservative surgical strategy. Several case reports have described spontaneous resolution of corneal blood staining [30,31]. Clearance typically progresses from the peripheral cornea toward the center and from posterior to anterior layers [31], consistent with our observations. This pattern has been attributed to limbal circulation and shedding of iron-containing epithelial cells [8]. Conjunctival flap coverage may further accelerate this process [32], possibly by increasing local blood supply. In our series, most eyes showed varying degrees of spontaneous clearance during follow-up, which enabled posterior segment assessment through this window. Fig 2 illustrates one case with complete clearance, the AS-OCT result showed a progressive reduction and eventual disappearance of hyperreflective stromal opacity.

Although corneal blood staining may clear spontaneously, this process can take months to years [5,30–32]. In contrast, the timing of PPV after severe ocular trauma is critical, as delayed intervention may increase the risk of proliferative vitreoretinopathy and lead to irreversible anatomical or functional loss [2,33,34]. Therefore, timely posterior segment access while avoiding unnecessary high-risk allograft PKP in the acute traumatic setting is essential. Our strategy addresses this dilemma by performing anterior chamber washout first, followed by TKP + PPV + RTC when visualization remains inadequate. Compared with conventional TKP-assisted PPV followed by immediate allograft PKP, this approach avoids placing donor tissue into an acutely inflamed and often silicone-oil-filled eye. Compared with endoscopy-assisted vitrectomy, it preserves a conventional wide-field microscopic surgical view and does not require specialized endoscopic equipment or a separate technical learning. Thus, this approach may provide a practical alternative for managing severe OGIs with corneal blood staining, particularly in centers where endoscopic vitreoretinal surgery is not routinely available.

Limitation

This study has several limitations. First, it was a retrospective analysis of a small cohort with highly heterogeneous severe ocular trauma, including variability in injury mechanism, posterior segment pathology, tamponade status, and follow-up duration. These factors, together with differences in the severity of corneal blood staining and corneal tissue damage, may have influenced the timing and extent of corneal clearing. Second, follow-up visits and AS-OCT imaging were not performed at standardized intervals. Therefore, the exact onset of corneal clearing could not be determined for every eye, and quantitative cohort-level AS-OCT analyses were not feasible. The analysis provided in the supplementary materials should be interpreted cautiously because of the limited sample size and substantial baseline imbalance. Finally, in this cohort of severe OGIs, final visual and anatomical outcomes were largely determined by posterior segment damage and overall ocular viability. Thus, the independent contribution of corneal blood staining to final BCVA, phthisis bulbi, or complete silicone oil removal could not be reliably isolated. Larger, prospective studies with standardized imaging, clinical grading, and follow-up protocols are needed to better define predictors of spontaneous clearance and to refine timing and selection of subsequent keratoplasty.

Conclusion

This conservative corneal strategy provides timely posterior segment access in severe OGIs complicated by corneal blood staining while preserving the globe and conserving corneal tissue. By avoiding routine immediate allograft PKP in the acute traumatic setting, it allows subsequent keratoplasty decisions to be guided by ocular stability, corneal status, and visual potential. These findings support selective, rather than routine, allograft PKP in such severely injured eyes.

Key messages

What is known

  • Corneal blood staining in open-globe injuries (OGIs) traditionally requires immediate allograft penetrating keratoplasty (PKP) to enable posterior segment access.

  • Immediate PKP in the acute phase is high-risk due to intense inflammation, hypotony, and long-term silicone oil tamponade.

What is new

  • This study highlights a globe-preserving and cornea-conserving strategy for severe OGIs complicated by corneal blood staining, using anterior chamber washout first, and TKP-assisted PPV with replacement of the trephined autologous cornea when necessary.

  • By avoiding routine immediate allograft PKP in the acute traumatic setting, this approach preserves the opportunity for later keratoplasty to be selected after ocular stabilization, based on overall ocular status, corneal condition, and visual potential, while reducing graft-related risks.

Supporting information

S1 File. Flow diagram of the study population enrollment from the EIVS database.

(PDF)

pone.0354967.s001.pdf (89.9KB, pdf)
S2 File. The first documented timing for corneal clearing.

The timing for corneal clearing varies widely among individual patients, as it depends on the severity and extent of the pre-operative opacity, as well as the severity of the ocular trauma. Given the retrospective nature of this cohort, follow-up visits were not scheduled at uniform intervals; thus the exact onset of corneal clearing could not be precisely determined for every eye, and only the timing of actual follow-up visits could be verified. These data should be interpreted cautiously.

(PDF)

pone.0354967.s002.pdf (58.6KB, pdf)

Data Availability

Data cannot be shared publicly because they involve clinical information and are subject to restrictions imposed by the Institutional Review Board of Peking University Third Hospital Medical Science Research Ethics Committee. Data are available from the Ethics Committee (contact via wangsiya745@126.com) for researchers who meet the criteria for access to confidential data.

Funding Statement

The author(s) received no specific funding for this work.

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Decision Letter 0

Ugochukwu Anthony Eze

22 Apr 2026

-->PONE-D-26-00677-->-->Clinical Course and Outcomes of Corneal Blood Staining in Open-Globe Injury: Eye Injury Vitrectomy Study-->-->PLOS One

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Reviewers' comments:

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Reviewer #1: Yes

Reviewer #2: Partly

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Reviewer #1: Yes

Reviewer #2: No

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Reviewer #1: Yes

Reviewer #2: No

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Reviewer #1: This article is generally well written and only requires minor revision. Some suggestions

Line 67 severe could be replaced by "the worst visual outcomes'

Line 113 , define what is an experience physician

Reviewer #2: Reviewer Comments

This manuscript addresses an uncommon but clinically relevant problem: the management of corneal blood staining in severe open-globe injury requiring posterior segment surgery. The authors present a conservative strategy in which anterior chamber washout is performed first, followed by TKP-assisted PPV with replacement of the trephined autologous cornea when visualization remains inadequate, while avoiding routine immediate allograft PKP. The topic is important, the case series is valuable for a relatively rare clinical scenario, and the photographic documentation is a strength. However, the manuscript requires major revision before it can be considered for publication. The main issues relate to incomplete characterization of cohort selection and follow-up, lack of a clearly defined corneal clearance outcome, limited analysis, underdeveloped AS-OCT reporting, and conclusions that are somewhat stronger than the data currently support.

Major comments

1. Study design and cohort selection need clearer reporting.

The manuscript states that this is a retrospective analysis of EIVS data, but it is unclear whether the 42 eyes represent a consecutive case series, a selected registry subset, or all eligible cases during a defined period (which was not stated). The authors should state the period during which the cases were selected, whether patients were consecutive, the number screened or excluded, and reasons for exclusion. A simple flow diagram would improve transparency and help readers assess selection bias and generalizability.

2. The central corneal outcome is not operationally defined.

The objective of this paper was to describe clinical course and outcome of corneal blood staining following the interventions. Yet, the paper’s main conclusion rests on “spontaneous clearance,” “corneal clarity,” and formation of a peripheral “window,” yet these outcomes are described narratively rather than systematically. The authors should define what constitutes sufficient clarity for PPV after washout, and how corneal status was graded clinically, photographically, or by AS-OCT, and whether grading was performed by one or more observers.

A formal grading system or at least reproducible categories would make the conclusions more credible.

3. Follow-up duration must be reported more adequately.

Since corneal blood staining clearance is inherently time-dependent, the actual follow-up duration of the cohort is essential. The manuscript should provide the median follow-up with IQR or range, and ideally also report time to partial clearance, time to complete clearance where achieved, and time to eventual PKP in the one transplanted eye.

4. The results should more clearly describe what happened to each subgroup.

The manuscript reports that 8 eyes achieved adequate clarity after anterior chamber washout alone, while 34 required TKP + PPV + RTC, but the later corneal course of each subgroup is not fully summarized. The authors should state:

•how many eyes achieved complete versus partial clearing,

•how many retained persistent central opacity or scarring,

•how many developed band keratopathy,

•whether all eyes eventually achieved a clinically useful fundus view,

•and whether corneal outcomes differed between the washout-only and TKP groups.

This has a tendency to further strengthen the clinical message.

5. AS-OCT is underdeveloped and should either be analyzed or toned down.

AS-OCT is included in the methods and highlighted in a representative figure, yet no cohort-level imaging findings are presented. If AS-OCT was routinely performed, the authors should summarize findings such as stromal hyperreflectivity, corneal thickness, and correlation with final corneal status. If it was not analyzable in a systematic way, then the discussion of AS-OCT’s prognostic value should be more cautious.

6. Visual outcome interpretation should be more cautious.

The manuscript reports statistically significant improvement in BCVA, but the cohort remains profoundly visually compromised overall, with many eyes presenting with NLP, many remaining NLP, and a proportion progressing to phthisis. The discussion and conclusion should avoid implying a strong functional benefit and should instead emphasize that this may be a globe-preserving and cornea-conserving strategy in eyes with otherwise poor prognosis.

7. Silicone oil status and IOP outcomes need deeper contextualization.

The paper notes that many eyes required additional silicone oil procedures and that only a few achieved complete oil removal. This is highly relevant because final IOP and eventual candidacy for corneal transplantation are likely influenced by recurrent posterior pathology, persistent hypotony, and the long-term graft-host environment. The manuscript should clarify how many eyes had secondary procedures, how many had oil refill, partial removal, or re-tamponade, whether final IOP was measured under oil in most eyes, and whether phthisical eyes were included in the IOP analysis

8. The indication and context for the single allograft PKP should be stated explicitly.

Because only one eye underwent PKP, that case is clinically informative. The manuscript should state the indication, timing, tamponade status, ocular condition, and visual/anatomical rationale for proceeding with PKP. This would help define the authors’ threshold for delayed transplantation.

9. The manuscript would benefit from association or predictor analyses.

The current analysis is mainly descriptive. Even in a modest sample, simple univariable or subgroup analyses would be useful. Potential comparisons include: washout-only versus TKP + PPV + RTC, complete versus incomplete corneal clearing, phthisis versus non-phthisis, final NLP versus retained light perception, eyes with and without useful fundus assessment, and associations with age, injury type (especially among the majority who had globe rupture), hypotony, retinal detachment, choroidal detachment, tamponade type, or no retina detected. This would strengthen the manuscript beyond a purely descriptive case series.

10. The strategy should be positioned more clearly relative to alternative approaches.

The discussion would be improved by explicitly comparing this approach with TKP plus immediate PKP, endoscopic vitrectomy, staged surgery, and observation before PPV where feasible. This would help readers understand when the proposed conservative approach is most appropriate in real-world practice.

Minor comments

1. Ethics approval inconsistency.

The ethics number differs between the submission material and the manuscript body and should be corrected.

2. Grammar and wording issues.

Several language issues need correction, including awkward or ungrammatical phrases.

3. Table 1.

Table 1 would be more informative if it included follow-up duration, number of reoperations, timing of silicone oil removal/refill, corneal outcome categories, and final transparency status.

4. Discussion wording and internal consistency.

Some phrases in the discussion are awkward and should be revised for clarity. There also appears to be an incorrect figure reference when discussing the case with complete clearance (check inserted comments).

5. References.

The reference list should be reviewed carefully for journal formatting and typographic consistency.

Overall recommendation

This is a clinically relevant manuscript with useful photographic documentation and an important practical message, especially in eyes with poor prognosis and limited donor-tissue justification. However, the paper currently needs substantial revision in outcome definition, follow-up reporting, and discussion balance before it is ready for publication.

**********

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Reviewer #1: Yes:  Annette K Hoskin

Reviewer #2: No

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Attachment

Submitted filename: PONE-D-26-00677_reviewed.docx

pone.0354967.s003.docx (514.7KB, docx)
PLoS One. 2026 Aug 4;21(8):e0354967. doi: 10.1371/journal.pone.0354967.r002

Author response to Decision Letter 1

31 May 2026

Reviewer #1: This article is generally well written and only requires minor revision. Some suggestions

Line 67 severe could be replaced by "the worst visual outcomes'

Line 113 , define what is an experience physician

Thank you very much for the positive evaluation of our manuscript and for these helpful suggestions.

For Line 67, we have revised the sentence accordingly. (Line 49, Page 4)

“Open-globe injuries (OGIs) are ocular injuries associated with the worst visual outcomes and may result in monocular or bilateral blindness, particularly in eyes with globe rupture ”

For the definition of “experience physician”. We agree that the term “experienced physician” was not sufficiently specific and could be misleading. We intended to indicate trained clinicians who were able to align serial AS-OCT scans by using anatomical landmarks and previous scan locations as references. We have revised the Methods to clarify this point. (Line 96- 99, Page 6)

“…AS-OCT (Wavelength nanometer, Tomey CASIA2, Nagoya, Japan) was performed by trained clinicians (AD, HW, and SG), with serial scans were obtained from same corneal regions whenever possible, using anatomical landmarks and previous scan locations as references.”

Please find the revisions highlighted in red.

Reviewer #2: Reviewer Comments

This manuscript addresses an uncommon but clinically relevant problem: the management of corneal blood staining in severe open-globe injury requiring posterior segment surgery. The authors present a conservative strategy in which anterior chamber washout is performed first, followed by TKP-assisted PPV with replacement of the trephined autologous cornea when visualization remains inadequate, while avoiding routine immediate allograft PKP. The topic is important, the case series is valuable for a relatively rare clinical scenario, and the photographic documentation is a strength. However, the manuscript requires major revision before it can be considered for publication. The main issues relate to incomplete characterization of cohort selection and follow-up, lack of a clearly defined corneal clearance outcome, limited analysis, underdeveloped AS-OCT reporting, and conclusions that are somewhat stronger than the data currently support.

Thank you for your comments.

Major comments

1. Study design and cohort selection need clearer reporting.

The manuscript states that this is a retrospective analysis of EIVS data, but it is unclear whether the 42 eyes represent a consecutive case series, a selected registry subset, or all eligible cases during a defined period (which was not stated). The authors should state the period during which the cases were selected, whether patients were consecutive, the number screened or excluded, and reasons for exclusion. A simple flow diagram would improve transparency and help readers assess selection bias and generalizability.

Thanks for this valuable suggestion.

This was a retrospective analysis of cases retrieved from the EIVS database between June 2012 and June 2025. As defined by the EIVS database, the general inclusion criteria were patients who suffered from severe eye injury and were treated with vitreoretinal surgery, enucleation, or evisceration [1].

A total of 3,152 eyes in the EIVS database were screened, including 1,920 eyes with open-globe injuries. Among them, 157 eyes had documented corneal blood staining. After excluding 115 eyes because of endophthalmitis, pre-existing ocular diseases, incomplete clinical or photographic records, follow-up shorter than 12 months, or enucleation/evisceration within 12 months; 42 eyes were included in the final analysis. We have added these details to the Methods and Results, and provided a flow diagram as S1 Figure.

Please find them highlighted in red (Line 81-83, Page 5; Line 89- 90, Page 6; Line 124- 128, Page 7)

2. The central corneal outcome is not operationally defined.

The objective of this paper was to describe clinical course and outcome of corneal blood staining following the interventions. Yet, the paper’s main conclusion rests on “spontaneous clearance,” “corneal clarity,” and formation of a peripheral “window,” yet these outcomes are described narratively rather than systematically. The authors should define what constitutes sufficient clarity for PPV after washout, and how corneal status was graded clinically, photographically, or by AS-OCT, and whether grading was performed by one or more observers. A formal grading system or at least reproducible categories would make the conclusions more credible.

We appreciate this comment.

In the revised manuscript, we defined “sufficient clarity for PPV after anterior chamber washout” as intraoperative corneal clarity that allowed the surgeon to safely identify major posterior segment structures and proceed with PPV without the use of TKP. We acknowledge that this criterion inevitably contains some degree of clinical judgment, because the feasibility of PPV depends not only on the size and location of the clear corneal area, but also on the extent of posterior segment pathology, the presence of iris or blood clot obstruction, and the surgeon’s experience. In this study, PPV without TKP was attempted only when the operating surgeon (including KF, YL, HC, LH and ZZM) considered that a continuous, unobstructed corneal viewing area was sufficient to permit safe posterior segment visualization and surgical manipulation. Otherwise, TKP-assisted PPV was performed. (Line 107- 113, Page 6 and 7, highlighted in red)

We also added reproducible postoperative corneal outcome categories, including complete clearing, partial clearing, and persistent opacity. “Complete clearing” was defined as complete disappearance of opacity attributable to corneal blood staining during follow-up, although other non-blood-staining corneal changes, such as scarring or band keratopathy, could still be present. “Partial clearing” was defined as recognizable decrease of corneal blood staining compared with the preoperative status, with formation of a clear corneal area sufficient for clinical posterior segment assessment, including retinal status and intraocular tamponade status. “Persistent opacity” was defined as residual corneal opacity due to blood staining that showed little or no regression compared with the preoperative status and continued to limit corneal transparency or fundus visualization.

Serial slit-lamp photographs, fundus photographs when available, and clinical records were independently reviewed by two ophthalmologists (KF and LH) to classify the corneal outcomes. Disagreements were resolved by a senior ophthalmologist (ZZM). These definitions have been added to the Methods (Line 114- 116, Page 7), and the corresponding subgroup results have been summarized in the Results (Line 140- 143, Page 8) and Table 1.

3. Follow-up duration must be reported more adequately.

Since corneal blood staining clearance is inherently time-dependent, the actual follow-up duration of the cohort is essential. The manuscript should provide the median follow-up with IQR or range, and ideally also report time to partial clearance, time to complete clearance where achieved, and time to eventual PKP in the one transplanted eye.

Thank you for highlighting this issue. We agree that follow-up duration is essential for interpreting the natural course of corneal blood staining. Previous reports have shown substantial variability in the speed of spontaneous clearing. In traumatic hyphema-related corneal blood staining, partial clearing has been observed within weeks to months, whereas complete clearing may require 10- 15 months or even up to 2- 3 years in some cases [2-5]. This variability suggests that the course of clearance may be influenced by the severity of corneal blood staining, as well as the degree of damage to the corneal endothelium and stroma.

In our series, all eyes had trauma-related corneal blood staining and underwent anterior chamber washout during surgery; however, the degree of hyphema, preoperative IOP, interval from injury to surgery, and tamponade / anterior segment status varied among patients. These factors may have contributed to heterogeneity in the timing and extent of corneal clearing.

Accordingly, we have added the median follow-up duration of 36 months (IQR, 23- 42 months; range, 12- 60 months) to the Results (Line 135- 136, Page 8) and Table 1. We also reviewed the available clinical records and serial photographs and reported the first documented visit at which partial or complete clearing was observed (S1 Table). The timing for corneal clearing varies widely among individual patients, as it depends on the severity and extent of the pre-operative opacity , as well as the severity of the ocular trauma. Specifically, the median time to partial clearing was 3 months (IQR, 3- 7.5 months), and the median time to complete clearing was 24 months (IQR, 10- 30 months). Given the retrospective nature of this cohort, follow-up visits were not scheduled at uniform intervals; thus the exact onset of corneal clearing could not be precisely determined for every eye, and only the timing of actual follow-up visits could be verified. We have clarified this limitation in the revised manuscript. (Page 15 and 16)

For the single eye that underwent allograft PKP, we now state that PKP was performed 14 months after the initial surgery, together with the ocular status at that time (Line 173- 183, Page 9 and 10).

4. The results should more clearly describe what happened to each subgroup.

The manuscript reports that 8 eyes achieved adequate clarity after anterior chamber washout alone, while 34 required TKP + PPV + RTC, but the later corneal course of each subgroup is not fully summarized. The authors should state:

•how many eyes achieved complete versus partial clearing

•how many retained persistent central opacity or scarring

•how many developed band keratopathy

•whether all eyes eventually achieved a clinically useful fundus view,

•and whether corneal outcomes differed between the washout-only and TKP groups.

This has a tendency to further strengthen the clinical message.

Thank you for this suggestion. In the supplementary materials, we have added a subgroup analysis comparing the washout-only group and the TKP + PPV + RTC group. The numbers of eyes with complete clearing, partial clearing, and persistent opacity have been added to the Results (Line 140- 144, Page 8) and Table 1.

Persistent central opacity or scarring was observed in 17/42 eyes. In this cohort of severe OGIs, residual central opacity may have resulted from multiple factors in addition to corneal blood staining, including the original corneal wound, suture-related scarring, and band keratopathy. Final visual function was also strongly affected by lens loss and severe posterior segment injuries, such as retinal detachment, choroidal detachment, and retinal tissue loss. Therefore, the independent functional impact of central opacity could not be reliably isolated in this retrospective study.

Band keratopathy was observed in 9 of 42 eyes, all of which were tamponaded with silicone oil. Because band keratopathy has been associated with long-term silicone oil tamponade, aphakia (which may facilitate direct contact between silicone oil and the corneal endothelium), hypotony, repeated intraocular surgery, and chronic inflammation [6, 7], we did not interpret it as a direct consequence of corneal blood staining. Instead, it is reported as a postoperative corneal complication in the context of severe ocular trauma.

We further clarified whether a clinically useful fundus view was achieved in each subgroup, including eyes with complete and partial clearing. In anterior chamber washout group (n = 8), 4/8 achieved complete clearing, while 4/8 showed partial clearing. In the TKP + PPV + RTC group (n = 34), 9/34 exhibited complete clearing, 18/34 presented partial clearing, and 7/34 suffered from persistent opacity.

For eyes with corneal opacity that limited direct visualization, including during the early postoperative period (e.g., at 1 week), posterior segment assessment was performed using B-scan ultrasonography, visual function examinations, and IOP measurement. The decision to perform subsequent PKP is strictly based on a comprehensive evaluation of both visual function and the anatomical viability of the injured eye; otherwise, allogeneic PKP is not recommended. (Line 209- 213, Page 12)

The data suggested that eyes in the washout-only group generally demonstrated faster and more complete clearing of corneal blood staining (please find it in S1 Table). Given the limited sample size and baseline imbalance, these subgroup findings are presented descriptively.

5. AS-OCT is underdeveloped and should either be analyzed or toned down.

AS-OCT is included in the methods and highlighted in a representative figure, yet no cohort-level imaging findings are presented. If AS-OCT was routinely performed, the authors should summarize findings such as stromal hyperreflectivity, corneal thickness, and correlation with final corneal status. If it was not analyzable in a systematic way, then the discussion of AS-OCT’s prognostic value should be more cautious.

We agree with the reviewer. In the original manuscript, AS-OCT was overemphasized relative to the available cohort-level imaging data. Although AS-OCT was useful for documenting representative anatomical changes, imaging was not performed using a standardized quantitative protocol at fixed postoperative intervals in all eyes. Therefore, reliable cohort-level analysis of stromal hyperreflectivity, corneal thickness, or correlations with final corneal status was not feasible. In the revised manuscript, we have toned down the AS-OCT-related statements, retained AS-OCT only as representative images, and added the lack of standardized serial AS-OCT analysis as a limitation. (Page 15 and 16)

6. Visual outcome interpretation should be more cautious.

The manuscript reports statistically significant improvement in BCVA, but the cohort remains profoundly visually compromised overall, with many eyes presenting with NLP, many remaining NLP, and a proportion progressing to phthisis. The discussion and conclusion should avoid implying a strong functional benefit and should instead emphasize that this may be a globe-preserving and cornea-conserving strategy in eyes with otherwise poor prognosis.

We appreciate this comment. We agree that although BCVA showed statistical improvement, the cohort remained severely visually compromised overall, and the visual outcome was mainly limited by the severity of posterior segment injury. We have deleted this sentence in Result and revised the Discussion and Conclusion to avoid implying a strong functional benefit. The revised manuscript now emphasizes that this approach should be interpreted primarily as a globe-preserving and cornea-conserving strategy that may reduce exposure to prolonged postoperative corticosteroid or immunosuppressive therapy and lower the risk of graft rejection in eyes with limited visual potential. (Page 13, 15, 16)

7. Silicone oil status and IOP outcomes need deeper contextualization.

The paper notes that many eyes required additional silicone oil procedures and that only a few achieved complete oil removal. This is highly relevant because final IOP and eventual candidacy for corneal transplantation are likely influenced by recurrent posterior pathology, persistent hypotony, and the long-term graft-host environment. The manuscript should clarify how many eyes had secondary procedures, how many had oil refill, partial removal, or re-tamponade, whether final IOP was measured under oil in most eyes, and whether phthisical eyes were included in the IOP analysis.

Thank you for this suggestion. We agree that silicone oil status, IOP, and secondary procedures are important for interpreting final ocular status and later PKP candidacy.

In this cohort, all eyes were followed for at least 12 months. Among the 40 eyes initially tamponaded with silicone oil, only 4 achieved complete silicone oil removal by the final visit. Therefore, final IOP in most eyes was measured in the presence of silicone oil or partial silicone oil tamponade. The remaining eyes required one or more silico

Attachment

Submitted filename: Response to Reviewers CBS po v2.docx

pone.0354967.s006.docx (165.3KB, docx)

Decision Letter 1

Ugochukwu Anthony Eze

16 Jul 2026

Clinical course and outcomes of corneal blood staining in open-globe injury: Eye Injury Vitrectomy Study

PONE-D-26-00677R1

Dear Dr. Ma,

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Attachment

Submitted filename: Reviewed_tracked_PONE-D-26-00677_R1.docx

pone.0354967.s005.docx (412.1KB, docx)

Acceptance letter

Ugochukwu Anthony Eze

PONE-D-26-00677R1

PLOS One

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Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 File. Flow diagram of the study population enrollment from the EIVS database.

    (PDF)

    pone.0354967.s001.pdf (89.9KB, pdf)
    S2 File. The first documented timing for corneal clearing.

    The timing for corneal clearing varies widely among individual patients, as it depends on the severity and extent of the pre-operative opacity, as well as the severity of the ocular trauma. Given the retrospective nature of this cohort, follow-up visits were not scheduled at uniform intervals; thus the exact onset of corneal clearing could not be precisely determined for every eye, and only the timing of actual follow-up visits could be verified. These data should be interpreted cautiously.

    (PDF)

    pone.0354967.s002.pdf (58.6KB, pdf)
    Attachment

    Submitted filename: PONE-D-26-00677_reviewed.docx

    pone.0354967.s003.docx (514.7KB, docx)
    Attachment

    Submitted filename: Response to Reviewers CBS po v2.docx

    pone.0354967.s006.docx (165.3KB, docx)
    Attachment

    Submitted filename: Reviewed_tracked_PONE-D-26-00677_R1.docx

    pone.0354967.s005.docx (412.1KB, docx)

    Data Availability Statement

    Data cannot be shared publicly because they involve clinical information and are subject to restrictions imposed by the Institutional Review Board of Peking University Third Hospital Medical Science Research Ethics Committee. Data are available from the Ethics Committee (contact via wangsiya745@126.com) for researchers who meet the criteria for access to confidential data.

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