Effect of lamellar keratoplasty after pre-Descemet’s membrane suture healing of acute corneal hydrops

doi:10.21203/rs.3.rs-2392446/v1

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Effect of lamellar keratoplasty after pre-Descemet’s membrane suture healing of acute corneal hydrops

https://doi.org/10.21203/rs.3.rs-2392446/v1

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Background: This study aimed to observe the effect of lamellar keratoplasty (LK) after pre-Descemet’s membrane (pre-DM) suture healing of acute corneal hydrops (ACH).

Methods: In a retrospective noncomparative case series, 11 patients (11 eyes) with ACH, who underwent pre-DM suture combined with intracameral air injection in the acute stage, underwent LK when the oedema subsided. During surgery, the diseased cornea was stripped layer by layer, and a mild scar in the deep stroma occasionally remained. The age, sex, diagnosis, scope of acute corneal oedema, size and location of scar after oedema healing, operation interval, postoperative best-corrected visual acuity (BCVA), astigmatism, and intraoperative and postoperative complications were recorded.

Results: The average follow-up time was 15.45 ± 8.54 months (6–30 months). The average time from corneal suture to LK was 41.91 ± 36.39 days. After LK, the BCVA was 0.52 ± 0.18 (0.15–0.8), astigmatism on the front surface of corneal topography was 5.63 ± 1.28 D, and apparent optometry CYL was -4.50 ± 1.87 D. The central corneal thickness was 552.81 ± 62.81 μm (449–637 μm). Microperforation occurred in two cases. No other complications occurred in any patients until the last follow-up.

Conclusions: LK can be performed earlier after the pre-DM suture of ACH. The combination of the two can shorten the overall course of the disease, significantly improve vision, and avoid the complications of penetrating keratoplasty.

Acute corneal hydrops

Pre-Descemet’s membrane

Complications

Lamellar keratoplasty

Acute corneal hydrops (ACH) occurs in approximately 2.6–2.8% of patients with keratoconus [1, 2]. ACH presents with corneal oedema because of a tear in Descemet’s membrane (DM) and endothelium, followed by leakage of aqueous humour into the stroma. The presentation includes severe vision loss, photophobia, redness, and grey eye [3]. ACH can self-heal over 2–6 months, depending on the extent of DM rupture. During this process, complications may occur, such as infection, intrastromal cleft formation, perforation, corneal neovascularisation, and a greater risk of corneal rejection after keratoplasty [4–6].

In the past 20 years, different treatments for ACH have been studied [7]. The objectives are to hasten the resolution of oedema, improve vision, or prepare for further surgery. Many studies have proposed various methods to promote oedema resorption [8–13]. While some studies argue that the risk of perforation may occur with deep lamellar keratoplasty (DLK) in the scar after ACH healing, recent studies argue that DLK can effectively improve vision after the oedema resolves [14–17]. To the best of our knowledge, this is the first study to observe the effect of lamellar keratoplasty (LK) or DLK in healed hydrops, performed after pre-DM sutures combined with intracameral air injection.

Patients

The data of 11 patients (11 eyes) with ACH who presented at Beijing Aier-Intech Eye Hospital between January 2016 and December 2021 were retrospectively collected. These patients, who had undergone pre-DM sutures combined with intracameral air injection in the acute stage, underwent LK once oedema subsided. Before the LK, the corneal scar was located in the central or paracentral area of the cornea, and the patients were dissatisfied with the best-corrected visual acuity (BCVA). The patients were followed up for 18.75 ± 15.53 months (6–60 months). This study was approved by the Institutional Review Board (BJAIER2021IRB18) of Beijing Aier-Intech Eye Hospital and followed the tenets of the Declaration of Helsinki. Written informed consent was obtained from all patients or their legal guardian(s), and LK was performed by a single surgeon.

The data collected included the patient’s age, sex, diagnosis; location and extent of the oedema; central corneal thickness (CCT); size, depth, and location of scar after ACH healing; BCVA; curvature and astigmatism of corneal topography; and spherical (S) and cylindrical (CYL) power at 1, 3, and 6 months and on the last follow-up.

Surgical technique

After ACH healed, LK surgery was performed. Although we were as close to the DM as possible, DM was not exposed completely; thus, it was near-DLK. The corneal trephine diameter was determined by measuring the area of scar involvement. Next, the host cornea was trephined to approximately 50% of its thickness, and 80% of the corneal depth was drilled and stripped layer by layer by the blade tip. Owing to the scar, big bubbles could not be used; therefore, we used small bubbles to separate the stroma and help determine the stripping depth. Anterior chamber paracentesis reduced the intraocular pressure to avoid DM tears. In the scar, the risk of perforation is high because the stroma and DM adhere closely and must be peeled carefully from the periphery going inwards without pulling. The implant bed was then kept as thin as possible, and the use of microsurgical scissors was preferred to blades. When microperforation occurs, anterior chamber gas injection can help complete the operation because air can block the leakage of the aqueous humour.

The donor button of all patients was made into appropriately sized grafts according to the length of the patient’s visual axis. The donor button was placed on the recipient bed and sutured with 16 interrupted 10/0 nylon sutures. The patients were administered tobramycin dexamethasone (Tobrex, Alcon NV, Switzerland) eye drops four times a day and ointments once nightly for the first month after the operation and reduced gradually according to the eye condition. If the suture loosens within 3 months, it needs to be resutured, but if it loosens after 3 months, it can be removed. After 6 months, the corneal sutures were removed selectively based on corneal astigmatism.

Evaluation of corneal oedema

The grading standard of corneal oedema was as follows [8]: grade I, within a circle of 3 mm diameter; grade II, within circles of 3–5 mm diameters; and grade III, larger than a circle of 5 mm diameter. The grading standard of corneal scar degree was as follows: grade I, not involving the pupil area; grade II, pupil area < 1/2; and grade III, pupil area ≥ 1/2.

LK was performed in 11 patients (eyes), including 10 men (90.91%) and 1 woman (9.09%), with an average age of 19.91 ± 4.01 years (15–28 years). Table 1 describes the pre-operational general conditions and corneal characteristics, including sex, age, the extent and grade of ACH oedema, the location and size of the scar after the oedema resolved, the time interval between LK and suture, and the changes in vision and astigmatism.

All eyes had corneal scars graded II or greater, including eight eyes (72.73%) with grade III corneal scars. The average time of corneal oedema reduction was 11.18 ± 7.45 days. After the oedema resolved, the degree of the corneal scar was grade II or above, involving the pupil, and six (54.55%) of the patients had a grade III scar.

The average follow-up time was 15.45 ± 8.54 (6–30) months. The follow-up time for seven eyes was ≥ 1 year. The BCVA of all patients before DLK was ≤ 0.3 (0.17 ± 0.14, 0.01–0.3). The average interval between the pre-DM suture and LK was 41.91 ± 36.39 (6–133) days (Table 1). The BCVA after corneal transplantation was improved. The BCVA at the last follow-up was 0.52 ± 0.18 (0.15–0.7), of which eight eyes had BCVA ≥ 0.5. The average astigmatism of the anterior surface of corneal topography was 5.63 ± 1.38 D, and the average CYL of optometry was − 4.50 ± 1.87 D (Table 2).

Microperforation occurred in two cases, but the LK was completed successfully. The residual scar of most cases decreased over time, and vision continued to improve. In some cases where the scar was located in the pupil area, the postoperative vision also exceeded expectations. After the operation, five eyes had double anterior chambers, of which four were well attached after applying liquid between the layers, and in one eye, the double anterior chambers disappeared spontaneously.

The average CCT at the last follow-up was 552.81 ± 62.81 µm (449–637 µm). No rejection and other complications occurred in all patients until the last follow-up (Table 2).

Table 1

General preoperative condition and corneal characteristics
Patient no.	Sex	Age (years)	Extent of oedema (mm)	Grading standard of corneal oedema	Cornea oedema resolution time	Grading standard of scar after the oedema healed	Corneal Scar range (mm)	BCVA before keratoplasty	Time interval between DLK and suture (d)
1	M	18	5.53 *3.67	III	18	III	5.43*2.00	0.01	21
2	M	22	5.40*4.13	III	14	III	4.67*3.38	0.3	80
3	M	17	7.90*7.31	III	28	III	6.55*3.02	0.15	25
4	M	28	4.47*4.10	II	7	III	5.07*2.26	0.2	34
5	M	20	5.26*4.40	III	5	II	3.56*2.89	0.1	6
6	M	19	3.86*2.70	II	15	II	4.60*2.51	0.02	19
7	M	25	4.68*3.25	II	3	II	4.39*2.07	0.3	32
8	M	15	7.78*5.94	III	13	II	5.57*3.33	0.5	21
9	M	22	6.43*6.09	III	5	III	7.57*1.25	0.3	133
10	M	16	8.07*6.63	III	10	II	6.00*3.41	0.1	58
11	F	17	6.80**5.67	III	5	III	5.21*2.26	0.2	32

Table 2

Intraoperative and postoperative data recording of pre-DM DLK
Patient no.	Microperforation during surgery	Suture pattern	Postoperative data
			Double chamber after surgery	Follow-up (months)	Last follow-up data
					BSCVA	Pentacam				Optometry		CCT (µm)
					BSCVA	K1	K2	Kmean	Astig	S	CYL	CCT (µm)
1	No	I	Yes	16	0.7	40.2	45.6	42.7	5.4	-5.00	-5.00	557
2	Yes	I	No	30	0.5	42.9	48.1	45.4	5.2	-2.00	-4.00	449
3	No	I	Yes	7	0.5	43.4	47.9	45.6	4.5	+ 1.00	-3.75	473
4	No	I	No	24	0.3	42.1	48.9	45.2	6.7	-4.50	-5.00	580
5	No	I	No	12	0.4	45.4	49.4	47.3	4	-4.75	-4.75	588
6	No	I	Yes	29	0.15	55.1	56.6	55.8	5.5	-1.00	-2.75	637
7	No	I	No	15	0.6	41.0	47.3	43.9	6.3	+ 4.00	-6.50	625
8	No	I	No	12	0.6	50.4	59.1	54.5	8.7	-9.25	-8.25	484
9	No	I	Yes	6	0.6	42.0	47.5	44.6	5.5	-4.00	-4.50	545
10	No	I	No	11	0.8	42.7	48.5	45.4	5.6	-1.00	-1.00	607
11	Yes	I	No	8	0.6	41.5	46.0	43.6	4.5	-3.75	-4.00	536

The self-healing time for ACH is long, and conservative management does not hasten healing. The healing time of oedema in treating corneal sutures was significantly shorter than that of self-healing [12, 13]. In this study, the reducing time after corneal suture was 11.18 ± 7.45 days, significantly shorter than that after conservative management. Some patients had significant regression of corneal oedema within 5days after suture placement (Fig. 1). Corneal oedema subsided in approximately 2 weeks in the present study, which is consistent with the results presented by Zhao et al. and Cherif et al. [12, 13]. However, previous studies did not further explore the follow-up treatment after healing.

Keratoconus occurs in young patients, and the age onset of ACH is younger. Therefore, the long-term survival of corneal grafts is very important. For young patients with keratoconus, DLK is the first choice. However, DLK has not been considered for deep scars involving DM for many years because of the risk of perforation [8]. Das et al. first reported a case of DLK after ACH healing. Although a scar was left in the optic axis area, the BCVA recovered to 1.0 [18]. Anwar et al. observed 22 eyes and performed near-Descemet dissection deep antibiotic lamellar keratoplasty on the patients after the ACH healing; perforation occurred in 6 eyes, and the operation was completed through intracameral gas injection [14]. These studies provide valuable information regarding the feasibility of subsequent DLK.

Previous studies mainly focused on DLK after self-healing of ACH. Zhao et al. [17] reported that 65% of patients had a BCVA of 0.63 (0.2 LogMAR) or better 24 months after the operation. In the 3-year follow-up results of Anwar et al., the average BCVA was approximately 0.5, and approximately 68% of the patients had BCVA ≥ 0.5 [14]. In our study, the average BCVA was 0.52 ± 0.18 (0.15–0.8). Eight (72.73%) patients had a BCVA of 0.5 or better, while 6 (54.55%) had a BCVA of ≥ 0.6. To the best of our knowledge, we are the first to observe the LK effect after pre-DM sutures. Our visual acuity results were similar to the two previous studies. Our patients had no rigid gas permeable contact lens vision correction, or the BCVA could have been better.

Few studies discuss the appropriateness of surgery. When the scar persists for a long time, the DM closely adheres to the stroma, increasing the difficulty of DLK and the risk of perforation. The scar also affects vision because it cannot be peeled off. Chew et al. advocated that DLK be performed no sooner than 4 months after the occurrence of hydrops because the healing process takes 4–6 months to be completed [16]. In our study, pre-DM sutures shorten the healing time of the ACH. Our results showed that LK was performed in all patients. The average interval between the pre-DM sutures and LK was 41.91 ± 36.39 days (6–133 days). We tried to perform LK at different times after the corneal oedema subsided. The LK time was gradually shortened from 4 months after the corneal oedema subsided. Most operations were completed in 3 weeks to 1 month. One case underwent LK 6 days after suture. A relatively good vision could be obtained in most patients. Therefore, surgery may be performed earlier, which may reduce the residual scar. One month after suturing may be a suitable interval. The corneal scar may still remain oedematous in some patients at this time, such that the residual scar may be uneven during the surgery, but it will improve with time. Nevertheless, further research on the optimal interval is needed before firm recommendations can be made.

However, because the healing of the DM rupture was not tight in the early stage, the big bubble technique could not be utilised to separate the stroma to avoid perforation. Pre-DM LK with manual stripping could be used. This method may affect vision in a few cases because of the non-uniform thickness of the recipient implant bed. This view is consistent with that of Nanavaty et al. [15]. In our study, one patient’s postoperative BCVA was poor as the implant bed was thicker and more uneven (Fig. 2). Therefore, we used microsurgical scissors to thin the implant bed. The scar, especially in the pupil area, was surgically excised as completely as possible. Anwar et al. found that the postoperative vision with residual scar is lower than that with penetrating keratoplasty and DLK without a scar. It is believed that the location and size of the scar impact the vision to some extent [14]. However, Zhao et al. found that the slight residual scars on the implant bed have no significant impact on the vision [17], consistent with the results of our study. We found that in the early stage of healing after keratoplasty, the stromal oedema in the residual scar area affects vision. Over time, the stromal oedema will reduce, and vision will improve (Figs. 3–5). In this study, most patients had a mild residual scar, but the average postoperative vision was 0.52 ± 0.18 (0.15–0.8). Therefore, we believe that retaining a mild scar may affect vision slightly, but it has less risk and greater benefit.

For ACH after suture of pre-DM, LK after ACH healing is an effective method to improve the vision, and the residual scar of deep stroma will not significantly affect the outcome. In our study, most patients can be performed LK in approximately 1 month. The suture of pre-DM combined with the LK can significantly shorten the healing time of the disease. This study provides a feasible method for the further treatment of ACH after suture of pre-DM.

This study has limitations. A larger series with a longer follow-up period is necessary to confirm the results. In addition, further studies should be conducted to assess the timing and methods of operation after suturing.

Ethics approval and consent to participate

This study approved by the Institutional Review Board (BJAIER2021IRB18) of Beijing Aier-Intech Eye Hospital and followed the tenets of the Declaration of Helsinki. Written informed consent for participation was obtained from all patients. The informed consent for all participants below the age of 16 was obtained from their parents or their legal guardian(s).

Consent for publication

All study participants provided informed consent for publication. The informed consent of publication for all participants below the age of 16 was obtained from their parents or their legal guardian(s).

Availability of data and materials

The datasets used and/or analysed during the current study are available from the corresponding author upon reasonable request.

Competing interests

The authors declare that they have no competing interests.

Funding

This work was supported by the Science Research Foundation of Aier Eye Hospital Group (grant number AR2104D3).

Authors’ contributions

All authors contributed to the study conception and design. JB and CL contributed to analysis and interpretation of data and drafted the manuscript. LZ, LL, WXS and LPH contributed to data analysis. SWL has reviewed this manuscript and given final approval. All authors commented on previous versions of the manuscript. All authors have read and approved the manuscript.

Acknowledgements

We would like to thank Editage (www.editage.cn) for English language editing.

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No competing interests reported.

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Effect of lamellar keratoplasty after pre-Descemet’s membrane suture healing of acute corneal hydrops

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Abstract

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Background

Methods

Patients

Surgical technique

Evaluation of corneal oedema

Results

Discussion

Conclusions

Declarations

References

Additional Declarations

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