Modified Conjoint Fascial Sheath and Levator Muscle Complex Suspension for the Correction of Simple Severe Congenital Ptosis in Pediatrics and the Effect on Refractive Status

Abstract

Purpose:

To evaluate the outcomes of modified combined fascia sheath and levator muscle complex suspension to correct severe congenital ptosis in pediatrics and the effect on refractive status.

Methods:

This prospective, case series study enrolled patients (aged ≤18 years) with simple severe congenital ptosis at Zhongshan Ophthalmic Center. All patients were treated with combined fascia sheath + levator muscle suspension and followed up for 3 months. Preoperative and postoperative cycloplegic refraction and the best-corrected visual acuity were performed. The types of astigmatism include with-the-rule, against-the-rule, and oblique.

Results:

Thirty-six patients (50 eyes) were enrolled. The mean age was 7.11 ± 3.72 years. The surgery success rate was 90.0%. Following surgery, the eyelid contour of all eyes exhibited natural symmetry and satisfactory curvature. The eyelid height difference in OUs was ≤1 mm for 42 eyes. For 47 eyes, the eyelid crease was symmetry. Two eyes had conjunctival prolapse, and 1 eye developed trichiasis. After surgery, cylinder power changed from mean −1.14 ± 1.27 D to −1.54 ± 1.25 D (p < 0.001) and best-corrected visual acuity improved from mean 0.205 ± 0.217 logarithm of the minimum angle of resolution to 0.168 ± 0.176 logarithm of the minimum angle of resolution (p = 0.048). The quantities of with-the-rule increased from 35 eyes to 41 eyes, oblique from 4 eyes to 6 eyes, while against-the-rule decreased from 11 eyes to 3 eyes (p = 0.01).

Conclusions:

Combined fascia sheath + levator muscle suspension under general anesthesia is effective and safe for severe congenital ptosis in pediatrics. However, astigmatism increased and the types of astigmatism changed after surgery.

Modified conjoint fascial sheath and levator muscle complex suspension under general anesthesia gives the satisfactory effect of correction and natural eyelid contour and few complications in severe congenital ptosis in children.

Congenital ptosis is the condition where one or both eyelids droop at birth, typically caused by inadequate development of the levator muscle (LM) responsible for lifting the eyelids.^1,2 This condition is often linked to amblyopia, refractive error, anisometropia, and strabismus. Severe ptosis impacts not only the appearance but also the visual function due to blockage of the pupillary area. The children may adopt an abnormal head posture as compensation, placing them at risk of developing amblyopia.³ Currently, surgery is the sole effective remedy to rectify ptosis. The selected operation relies on the extent of ptosis and LM function. For patients with severe ptosis, frontalis suspension surgery is the traditional method. Nevertheless, it involves multiple complications, including poor ocular mobility, unnatural eyelid contour, superior palpebral hysteresis, apparent lagophthalmos, raised eyebrows, and intensification of forehead wrinkles.⁴ Some new surgical procedures to correct severe congenital ptosis are necessary.

Conjoint fascial sheath (CFS) suspension has been used to correct congenital ptosis.⁵ However, the outcomes of CFS surgery on severe ptosis have not been satisfactory.^5,6 Long-term follow-up observations have revealed the shortcomings of CFS suspension surgery on severe ptosis, including undercorrection or recurrence, which can be attributed to the relatively weak and nonfirm adhesion of only CFS suspension.⁷ Recently, a modified surgery known as CFS + LM complex suspension has exhibited positive outcomes in correcting severe ptosis.^6–10 However, CFS + LM surgery for simple severe congenital ptosis in children is performed under general anesthesia, and the amount of surgical correction cannot be adjusted during the operation according to the patient’s cooperation. Hence, the operation is more challenging than in adults.

Congenital ptosis is known to alter the corneal curvature and topography and cause refractive errors due to excessive mechanical pressure from the eyelid.¹¹ The effects of ptosis surgery on refractive error during the critical period of visual development in children need to be noted. After the congenital ptosis operation, the eyelid’s position changes and the mechanical pressure of the eyelid on the cornea changes, which may change the refractive status.¹² Previous studies have shown the effects of frontalis muscle flap suspension or LM resection on refractive errors in patients with blepharoptosis.^12–14 Until now, no study has investigated the effects of CFS + LM suspension surgery on refractive errors.

This study aimed to evaluate the surgical outcomes of CFS + LM suspension for the correction of severe congenital ptosis, to analyze the applicability of this technique in pediatric patients, and to investigate the effect on refractive status. These findings will be a foundation for developing vision rehabilitation and amblyopia treatment plans after CFS + LM surgery.

SUBJECTS AND METHODS

Subjects

A prospective, case series study was conducted in the Oculoplastic Department at Zhongshan Ophthalmic Center, Sun Yat-sen University between November 2022 and March 2023. The study enrolled patients under 18 years of age with simple congenital ptosis. All participants provided signed informed consent. The inclusion criteria comprised confirmed simple congenital ptosis and the LM function ≤4 mm, dependable measurement outcomes, and lack of other ocular pathology. Patients with myasthenia gravis, blepharophimosis-ptosis-epicanthus inversus syndrome, Marcus Gunn jaw winking syndrome, and strabismus, those who had difficulty cooperating with the examination, refusal to follow up, and individuals with a history of previous eye surgery or trauma were excluded from the study. Severe ptotic eyes that underwent ptosis surgery were included in the case group. Nonoperated eyes were considered as the control group. Written informed consent was obtained from all the study participants. Patient or guardian consent for the publication of the photos in this article is archived by the authors. The study followed the tenets of the Declaration of Helsinki and ethics approval was granted by the Institutional Review Board of the Zhongshan Ophthalmic Center (No. 2023KYPJ273).

Ophthalmic Examination

All patients underwent routine preoperative ophthalmic examinations in OU, including slit-lamp examination, detailed fundus examination, cover test, extraocular movements, cycloplegic retinoscopy refraction, and best-corrected visual acuity (BCVA) measurements. Using compound tropicamide eye drops to dilate the pupils sufficiently for cycloplegic retinoscopy, BCVA was measured with the International Standard Visual Chart and recorded as the logarithm of the minimum angle of resolution (logMAR). Spherical power, cylinder power, and astigmatic axis were recorded, with cylinder power counted as negative. Astigmatism was divided into 3 categories: with-the-rule (WTR) astigmatism (negative cylinder axis 180° ± 30°), against-the-rule (ATR) astigmatism (negative cylinder axis 90° ± 30°), and oblique (OBL) astigmatism in other orientations.¹⁵ A senior doctor assessed the height of the palpebral fissure (HPF), the upper lid marginal reflex distance (MRD1), and the LM function twice. Ptosis was defined as a MRD1 of <2.5 mm.¹⁶ Ptosis was classified as mild (MRD1 ≥ 2 mm), moderate (0 ≤ MRD1 < 2 mm), and severe (MRD1 < 0 mm).¹³

Postoperative Evaluation

Follow up 3 months after surgery by the same physician, with the same examination item as before. The operative effect was evaluated, and HPF, MRD1, the degree of lagophthalmos, extraocular movements, strabismus, and postoperative complications were recorded. The evaluation criteria of correction effect were as follows: good, the MRD1 ≥ 2.5mm; basic correction, the upper eyelid margin was located between the upper edge of the pupil and MRD1< 2.5 mm; deficiency, upper eyelid margin to cover the upper edge of the pupil; uncorrected, ptosis as before; and overcorrection, upper eyelid margin in the upper corneal margin and above. The criteria for surgical success were defined as good and basic correction of the ptosis. The evaluation of appearance effects includes eyelid contour, eyelid height symmetry, and eyelid crease. The eyelid contour scores: 3 points was natural symmetry, satisfactory curvature, no peak, family member and doctor were very satisfied; 2 points was moderate peak or flat eyelid, family member and doctor were basically satisfied; 1 point was eyelids appearance needed to be redone, family member and doctor were not satisfied. The scores of eyelid height symmetry: 3 points was the difference of eyelid height ≤1 mm; 2 points was the difference of eyelid height 1–2 mm; 1 point was the difference of eyelid height >2 mm. The eyelid crease scores: 3 points was crease symmetry, no elimination; 2 points was crease partial disappearance, asymmetry, but acceptable; 1 point was crease complete disappearance, unacceptable.

Surgical Method

The CFS + LM suspension was used for patients with severe ptosis whose LM function was ≤4 mm. The operation was performed under a microscope by the same surgeon, Rongxin Chen, following the same procedure. The procedure of CFS + LM suspension surgery for the correction of simple severe congenital ptosis in pediatrics was shown in Figure 1 and Video, Supplemental Digital Content 1, available at http://links.lww.com/IOP/A394.

FIG. 1.

The procedure of CFS + LM suspension surgery for the correction of simple severe congenital ptosis. A, The patient takes the supine position under general anesthesia. Design the incision and mark the line. An equal mixture of 2% lidocaine and ropivacaine with 1:100,000 epinephrine was used for local lid infiltration anesthesia. Cut the skin and the upper eyelid was sutured with 5-0 nonabsorbable suture to make traction to expose the surgical field. Remove the skin band. B, The anterior tarsal tissue was separated from the tarsal plate, and the levator aponeurosis and levator muscle were fully exposed. C, The separation continued upward, and Whitnall’s ligament and orbital septum were exposed. The ligament of Whitnall and the medial and lateral ligaments of the levator aponeurosis have been cut to remove their restriction on the levator muscle. D, The orbital septum was opened and repaired after partial removal of bulging fatty tissue. E, The upper eyelid was inverted, and the mixture of lidocaine and ropivacaine was injected to hydrodissect the levator aponeurosis and tarsal conjunctiva. F, The levator aponeurosis was cut off about 5 mm from the upper edge of the tarsal plate, and the levator muscle and Müller muscle complex were separated from the conjunctiva. G, The combined fascia sheaths were opalescent and separated from the superior fornix to form the CFS + LM composite flap. H-J, The LM + CFS were fixed at 1/2 of the tarsal plate with 3 pairs of mattress sutures with the 5-0 nonabsorbable suture to make the palpebral margin reach the calculated height of the palpebral fissure. K, The surplus levator aponeurosis was excised. L, The skin was sutured to form a double eyelid crease. CFS, combined fascia sheath; LM, levator muscle.

The palpebral fissure height calculated during surgery in the patients with binocular surgery = 10 mm − preoperative palpebral fissure height + intraoperative lagophthalmos + 1.5 mm. The HPF calculated during surgery in the patients with monocular surgery = the absolute value of the MRD1 difference in OU + intraoperative lagophthalmos + 1.5 mm.

Statistical Analysis

Statistical analysis was conducted using SPSS software version 25.0. Frequency and percentage were employed for categorical variables, while mean ± standard deviation was used for continuous variables. Categorical variables underwent χ² or Fisher exact test. The paired Wilcoxon rank-sum test was also applied to compare preoperative and postoperative results if the continuous variables did not conform to normal distribution. Independent samples Mann-Whitney U test were used to compare operated versus control eyes. Spearman correlation analysis was used when continuous variables were not in normal distribution. A p of <0.05 was considered significant. GraphPad Prism 9.5 was used for plotting.

RESULTS

Thirty-six patients (50 eyes) with simple severe congenital ptosis undergoing modified CFS + LM suspension were enrolled in this study. The demographic data of the patients are presented in Table 1. The mean age of patients was 7.11 ± 3.72 years (range from 3.33 to 18 years old). The correction effect of ptosis was good in 20 eyes (40%), basic correction in 25 eyes (50%), and deficiency in 5 eyes (10%). The surgery success rate was 90.0% (45/50). Figure 2 showed 2 typical cases of successful surgery. Following CFS + LM suspension surgery, the eyelid contour of all 50 eyes (100%) exhibited natural symmetry, satisfactory curvature and no peaks. Both family members and doctors expressed high satisfaction. Of the 50 eyes, the eyelid height difference in OU was ≤1 mm for 42 eyes (84%) and 1–2 mm for 8 eyes (16%). For 47 eyes (94%), the eyelid crease was symmetry and had no elimination, while 3 eyes (6%) exhibited eyelid crease partial disappearance or asymmetry, which was deemed acceptable. All patients had normal extraocular movements, and no strabismus was found during the follow-up period. However, the degree of lagophthalmos increased in 43 eyes after surgery. Additionally, conjunctival prolapse occurred in 2 cases (2 eyes) and recovered spontaneously after conservative treatment; 1 case (1 eye) developed upper eyelid trichiasis on the first postoperative day due to swelling of the upper eyelid, which improved after 2 times of contact lens wear; and some patients have asymptomatic patchy defects in the corneal epithelium.

TABLE 1.

Baseline demographic characteristics

	n (%)
n	36
Sex
Male	22 (61.1)
Female	14 (38.9)
Laterality
Unilateral	22 (61.1)
Bilateral	14 (38.9)
Age (year)	7.11 ± 3.72
Follow-up time (month)	3.34 ± 0.46
Corrective effect
Good	20 (40.0)
Basic correction	25 (50.0)
Deficiency	5 (10.0)
Surgical success	45 (90.0)
Eyelid contour score
3	50 (100.0)
2	0 (0.0)
1	0 (0.0)
Eyelid height symmetry score
3	42 (84.0)
2	8 (16.0)
1	0 (0.0)
Eyelid fold score
3	47 (94.0)
2	3 (6.0)
1	0 (0.0)
Complications (eye)
Lagophthalmos	43 (86.0)
Conjunctival prolapse	2 (4.0)
Exposure keratopathy	0 (0.0)
Trichiasis	1 (2.0)

FIG. 2.

Preoperative and postoperative appearance of typical patients undergoing unilateral and bilateral CFS + LM suspension surgery. Case 1, ptosis of the OS: A, Preoperative left palpebral fissure height was 3 mm, and function of the levator muscle was 3 mm. B, Preoperative lagophthalmos of the OS was 0 mm. C, Postoperative height of the left palpebral fissure was 8 mm, which is essentially symmetrical with the OD. D, Postoperative lagophthalmos of the OS was 1 mm. E, F, Postoperative upward and downward gaze of the OS, respectively. F, Postoperative superior palpebral hysteresis occurred in the OS. Case 2, bilateral ptosis: A, Preoperative right palpebral fissure height was 6 mm, levator muscle function was 4 mm, and preoperative left palpebral fissure height was 4 mm, levator muscle function was 1 mm. B, Preoperative lagophthalmos of bilateral eyes were 0 mm. C, postoperative bilateral height of the palpebral fissure was 8 mm, with symmetry in the height and curvature of OUs and good eyelid crease. D, Postoperative lagophthalmos of the bilateral eyes was 1 mm in the OD and 3 mm in the OS. E, F, The postoperative upward and downward gaze of the bilateral eyes, respectively. F, Postoperative superior palpebral hysteresis occurred in the bilateral eyes. CFS, combined fascia sheath; LM, levator muscle.

The appearance and refractive status of severe ptotic eyes and control eyes before surgery were compared. The mean MRD1 in the ptotic group was −1.48 ± 1.13 mm and in the control group was 2.66 ± 0.73 mm. The mean LM function in the ptotic group was 2.97 ± 1.51 mm and in the control group was 10.27 ± 1.45 mm. There was no significant difference in sphere power (p = 0.772), cylinder power (p = 0.246), and astigmatism type (p = 0.183) between the severe ptotic group and the control group. The mean BCVA in the ptotic group was 0.205 ± 0.217 logMAR and in the control group was 0.061 ± 0.090 logMAR. There was a significant difference in BCVA (logMAR) between the 2 groups (p = 0.004).

Preoperative and postoperative appearance and refractive status of severe ptotic eyes and control eyes were shown in Table 2. Before and after CFS + LM suspension surgery, there were significant differences in the severe ptotic group regarding the HPF (3.49 ± 1.17 mm vs. 7.28 ± 1.00 mm, respectively; p < 0.001), lagophthalmos (0.33 ± 0.58 mm vs. 1.84 ± 1.19 mm, respectively; p < 0.001), cylinder power (−1.14 ± 1.27 D vs. −1.54 ± 1.25 D, respectively; p < 0.001), and BCVA (logMAR) (0.205 ± 0.217 logMAR vs. 0.168 ± 0.176 logMAR, respectively; p = 0.048), but there was no significant difference in sphere power (p = 0.368). After CFS + LM suspension surgery, the mean increase in HPF was 2.60 ± 2.17 mm, the mean increase in lagophthalmos was 1.51 ± 1.21 mm, BCVA significantly increased by a mean of 0.041 ± 0.107 logMAR, cylinder power changed by a mean of −0.30 ± 0.59 D, and astigmatism types also changed (p = 0.01).

TABLE 2.

Comparison before and after operation

	CFS + LM suspension group			Control group
	Before	After	p	Before	After	p
HPF, mm	3.49 ± 1.17	7.28 ± 1.00	<0.001*	7.66 ± 0.76	7.55 ± 0.63	0.687
MRD1, mm	−1.48 ± 1.13	2.25 ± 0.86	<0.001*	2.66 ± 0.73	2.46 ± 0.58	0.341
Lagophthalmos, mm	0.33 ± 0.58	1.84 ± 1.19	<0.001*	0.02 ± 0.11	0.34 ± 0.71	0.063
Cycloplegic refraction
Sphere power, D	0.59 ± 2.79	0.54 ± 2.73	0.368	0.72 ± 2.44	0.53 ± 2.44	0.008*
Cylinder power, D	−1.14 ± 1.27	−1.54 ± 1.25	<0.001*	−0.72 ± 0.80	−0.77 ± 0.83	0.434
Astigmatism type (n, %)			0.01†			0.136
WTR	35 (70.0)	41 (82.0)		19 (86.4)	21 (95.5)
ATR	11 (22.0)	3 (6.0)		1 (4.5)	0 (0.0)
OBL	4 (8.0)	6 (12.0)		2 (9.1)	1 (4.5)
BCVA (logMAR)	0.205 ± 0.217	0.168 ± 0.176	0.048†	0.061 ± 0.090	0.020 ± 0.040	0.006*

^*p < 0.01.

^†p < 0.05.

ATR, against-the-rule; BCVA, best-corrected visual acuity; CFS, combined fascia sheath; HPF, height of palpebral fissure; LM, levator muscle; logMAR, logarithm of the minimum angle of resolution; MRD1, the upper lid marginal reflex distance; n, number; OBL, oblique; WTR, with-the-rule.

Specifically, astigmatism decreased in 12 eyes (24%), remained unchanged in 5 eyes (10%), and increased in 33 eyes (66%) after CFS + LM suspension surgery (Fig. 3). Moreover, astigmatism variation after surgery was not significantly correlated with age (r = 0.025, p = 0.865), MRD1 variation (r = −0.152, p = 0.292), and lagophthalmos variation (r = 0.001, p = 0.994). In addition, WTR increased from 35 eyes (70%) to 41 eyes (82%) and OBL from 4 eyes (8%) to 6 eyes (12%), while ATR decreased from 11 eyes (22%) to 3 eyes (6%) after CFS + LM suspension surgery. At 3 months postoperatively, the astigmatism pattern remained the same as preoperatively in 36 (72%) of the operated eyes. Of the 14 eyes (28%) that had a change in astigmatism pattern postoperatively, 9 eyes (64.3%) reported a change in astigmatic direction to WTR, with 6 (66.7%) changing from ATR to WTR and 3 (33.3%) changing from OBL to WTR. Five eyes (35.7%) had a change in astigmatism direction to OBL, with 3 (60%) changing from WTR to OBL and 2 (40%) changing from ATR to OBL.

FIG. 3.

Cylinder power variation after CFS + LM suspension surgery. After CFS + LM suspension surgery, astigmatism decreased in 12 eyes, of which the change in cylinder power was ≤0.5 D in 9 eyes and >0.5 D and ≤1.0 D in 3 eyes. Astigmatism remained unchanged in 5 eyes. There was an increase in astigmatism in 33 eyes, of which the change in cylinder power was ≥−0.5 D and <0 D in 13 eyes, ≥−1.0 D and <−0.5 D in 14 eyes, and <−1.0 D in 6 eyes. CFS, combined fascia sheath; LM, levator muscle.

DISCUSSION

In recent years, CFS + LM suspension has been used to treat severe congenital ptosis, but its applicability in children is rarely studied. It is essential to evaluate the efficacy and safety of CFS + LM suspension for severe congenital ptosis in children. In addition, it is very important to determine the effect of CFS + LM suspension on refractive status, which can provide the basis for vision rehabilitation and amblyopia treatment plans after ptosis operation.

In 1901, Fergus initially documented using the frontalis muscle flap suspended on the tarsal plate to remedy severe blepharoptosis, a practice dating back over 100 years. Since then, it has been the mainstay of treatment for severe ptosis. However, frontalis suspension can alter the direction of upper eyelid lifting. Additionally, postoperative complications, including lagophthalmos, eyelid separation from the eyeball, unnatural double eyelids, and uncoordinated eye movement, are relatively common.¹⁷ Upper lid excursion was worse because the frontalis flap was less elastic than the LM, increasing the risk of lagophthalmos and closure insufficiency.⁷ Thus, CFS suspension was born.

The CFS, also known as the connective tissue fascia superioris, is between the levator and superior rectus muscle. The main force of CFS is derived from the superior rectus muscle and reserving the original function of the LM, which provides sufficient force to lift the upper eyelid.¹⁸ In addition, the direction of contraction of the superior rectus muscle is basically the same as that of the LM. In comparison to frontalis suspension, CFS suspension more closely aligns with physiological characteristics, avoiding the drawbacks associated with frontalis suspension.¹⁷ Hwang et al.¹⁹ described that the structure had a length of 12.2 ± 2.0 mm, a thickness of 1.1 ± 0.1 mm, and an equilateral trapezoid shape with a longer anterior base. Holmstrom et al.⁵ suspended the CFS structure on the tarsal plate to correct ptosis and achieved good results. However, some patients with severe ptosis experienced upper eyelid retraction after CFS suspension alone.⁴ CFS suspension is only effective for a short time postoperatively.⁴ Simple CFS suspension has a high incidence of upper eyelid retraction and recurrence of ptosis.⁶ The CFS suspension alone lacks firm attachment points and does not maintain long-term tissue tension. The thickness and width of the CFS vary from patient to patient. The weaker the CFS, the less likely it is to adhere to the tarsal tissue.⁷ Thus, modified CFS and LM complex suspension for severe congenital ptosis has emerged. Previous studies have concentrated on the effectiveness of CFS + LM suspension in adult patients who could tolerate local anesthesia.⁶ However, its use in correcting severe blepharoptosis in children under general anesthesia poses difficulties in accurately measuring the correction degree. The reason is that the depth of general anesthesia varies and the position of the cornea changes during surgery. Therefore, CFS + LM suspension presents a challenge for children.

Recently, CFS + LM suspension has been used to treat severe congenital ptosis in children and good results have been achieved.¹⁰ Wang et al.¹⁰ conducted a study on 3–7-year-old children with severe congenital ptosis using CFS + LM suspension and found a 77.78% correction, exceeding the 67.92% reported in a previous study.⁴ Wang et al.¹⁰ discovered that 3 months after CFS + LM suspension, palpebral fissure height basically remained stable. They concluded that CFS + LM suspension exhibits excellent long-term results for severe congenital ptosis in pediatrics, such as satisfactory eyelid movement and closure and fewer postoperative complications. In our study, CFS + LM suspension was performed in children aged 3–18 years with severe congenital ptosis and the success rate of this procedure was 90% after 3 months. In addition, all the surgical eyes obtained a natural appearance and satisfactory contour and crease of the eyelid. The CFS + LM suspension maintains the upper eyelid’s original physiological structure, facilitating the attainment of natural and esthetically pleasing curvature of the eyelid margin in children and the long-term avoidance of margin deformities. Motility is in keeping with the natural structure, and adequate blinking function can be maintained to some extent. Meanwhile, the CFS + LM suspension also prevents upper eyelid hypertrophy and scarring and does not depend on eyebrow elevation when opening the eyes, unlike frontalis suspension.¹⁰ In this study, after CFS + LM suspension, the degree of lagophthalmos increased in 43 eyes, 2 eyes had conjunctival prolapse and recovered spontaneously after conservative treatment, and 1 eye developed upper eyelid trichiasis due to swelling of the upper eyelid. A significant complication of severe ptosis after CFS + LM suspension is lagophthalmos, which can result in exposure keratitis and other complications. Therefore, it is crucial to provide special attention to postoperative care and guide patients’ families on using eye-closed treatment and other nursing techniques.²⁰ Another complication is conjunctival prolapse. Intraoperative injury to the suspensory ligament during CFS separation may result in prolapse of the fornical conjunctiva. Intraoperative or postoperative swelling or bleeding may also result in the prolapse of the superior fornix.⁷

This study found that the BCVA (logMAR) was greater in the severe ptotic eyes than the nonseverely ptotic ones, which may indicate inferior visual acuity in the former. Severe congenital ptosis can result in amblyopia, which has a detrimental effect on BCVA. Patients with severe ptosis are faced with an obstruction of the visual axis, which threatens normal visual development. This may lead to astigmatic refractive amblyopia or stimulus deprivation.²¹ In this study, the percentage of WTR was 70% in the severe ptotic group and 86.4% in the control group, and the percentage of ATR was 22% in the ptotic group, greater than the 4.5% in the control group. Tan et al.²² analyzed refractive features in children with severe congenital ptosis. They found that ptotic eyes presented with relatively higher frequencies of ATR types of astigmatism, which can severely impair vision. This finding was in line with our study.

In addition, after CFS + LM suspension surgery, the mean cylinder power and BCVA (logMAR) were smaller than those before the operation. This means that postoperative astigmatism worsened, but BCVA improved. In this study, astigmatism increased in some eyes after surgery, decreased in some eyes, and remained unchanged in some eyes after surgery. The number of WTR and OBL were increased, and ATR was decreased, while there was no significant difference in sphere power after CFS + LM suspension. Gandhi et al.¹² conducted frontalis sling surgery to treat severe congenital ptosis and observed an enhancement of BCVA after the intervention, consistent with our study findings. The enhanced visual stimulation following the surgery may have resulted from the removal of visual axis obstruction in severe ptosis.²¹ This result suggested that surgical correction of severe congenital ptosis can promote the treatment of amblyopia. Congenital ptosis, caused by excessive mechanical pressure on the eyelids, has been shown to alter corneal curvature and topography, resulting in refractive error.¹¹ Theoretically, elevating the drooping eyelid may reduce the mechanical force on the cornea and rectify astigmatism, and cause the steepened vertical meridian to become flat. However, several studies have shown increased astigmatism after ptosis surgery in pediatric patients. Merriam et al.²³ reported a significant occurrence of astigmatic errors after surgery with congenital ptosis. Moreover, 15% of the patients experienced an elevation in corneal steepening along the 90° meridian after undergoing the procedure. They hypothesized that lifting the eyelid surgically may create pressure on the superior globe, resulting in steepness in the aforementioned meridian or a WTR alteration. Tan et al.²² examined the refractive alterations following frontalis suspension in children with severe congenital ptosis. The study revealed an increase in astigmatism in the affected eye 1 month after the operation, which decreased gradually at 6 months follow up and decreased significantly at 1 year after the operation. Paik et al.¹³ found that the changes in astigmatism magnitude before and after ptosis surgery of congenital ptosis were not significant, but the proportion of subjects with OBL increased significantly. The findings of the current investigation are inconclusive regarding alterations in astigmatism pre- and postptosis surgery. This discrepancy may be associated with the age and type of the participants examined, the severity of blepharoptosis, the amount of MRD1 correction, the surgical method chosen, and the duration of follow up. In this study, the increased astigmatism following CFS + LM suspension may be attributable to early postoperative edema of the upper eyelid and surrounding tissue.^22,24

We showed that early mean astigmatism was increased after CFS + LM suspension for severe congenital ptosis in pediatric patients. This result indicated the necessity of monitoring astigmatic changes postsurgery. Importantly, these changes are not temporary and persist for up to 3 months after ptosis repair surgery. Therefore, in order to reduce the effect of postoperative astigmatism on amblyopia, it is particularly important to monitor and correct the astigmatism of these children. The results of this study also enhance our attention to the early increased astigmatism after severe congenital ptosis surgery of CFS + LM suspension in children, which helps to guide further treatment soon after surgery.

This study is the first to analyze the changes in refractive status after CFS + LM suspension surgery to correct severe congenital ptosis in pediatric patients. However, several limitations in the present study should not be ignored. First, our results reflect only the success rate and refractive status at 3 months after CFS + LM suspension and lack of long-term follow up. Second, the sample size is limited. In addition, frontalis muscle flap suspension as a control group is lacking. Larger sample size, frontalis muscle flap suspension as a control group, and the long-term surgical effect are needed in future studies.

In conclusion, CFS + LM suspension is an effective treatment for severe congenital ptosis in pediatric patients with excellent outcomes. It is still safe and feasible for correcting severe congenital ptosis in pediatric patients under general anesthesia. This technique has a natural appearance and fewer complications, which is worthy of further clinical application. In addition, early astigmatism increased and the types of astigmatism changed following CFS + LM suspension surgery. Hence, it is imperative to prioritize the timely rectification of refractive errors following ptosis surgery to promote vision rehabilitation and thwart the exacerbation of amblyopia.

ACKNOWLEDGMENT

The authors gratefully thank the staff of the Laboratory Department of Zhongshan Ophthalmic Center for the cycloplegic retinoscopy refraction examination.