Journal of Refractive Surgery

Original Article 

Femtosecond Laser–Assisted LASIK in Children With Hyperopia and Anisometropic Amblyopia: 7 Years of Follow-up

Irina Leonidovna Kulikova, MD, PhD; Nikolay Petrovich Pashtaev, MD, PhD; Yevgeniy Nikolayevich Batkov, MD, PhD; Svetlana Mikh'ilovna Pikusova, MD; Anna Evgen'evna Terent'eva, MD

Abstract

PURPOSE:

To analyze clinical and functional results of femtosecond laser–assisted laser in situ keratomileusis (FSLASIK) in children with hyperopia and unilateral anisome-tropic amblyopia.

METHODS:

The study included 24 patients (24 eyes) aged 5 to 15 years. Before the surgery, the mean manifest refractive spherical equivalent (MRSE) of amblyopic eyes was +3.90 ± 1.60 diopters (D) (range: +1.50 to +6.80 D) and the mean refractive anisometropia was 3.06 ± 1.64 D (range: 0.87 to 7.50 D). Every patient had at least 1 year of ineffective traditional amblyopia treatment before surgery. The mean follow-up period was 7 years (range: 6.9 to 7.4 years).

RESULTS:

At the final follow-up visit, the mean MRSE of operated eyes was +0.41 ± 1.35 D (range: −1.13 to +3.88 D) (P < .001) and anisometropia in MRSE notation was 1.39 ± 1.15 D (range: 0.00 to 4.63 D). Postoperative spherical equivalent was within ±0.50, ±1.00, and ±2.00 D in 31%, 38%, and 92%, respectively. There were no complications. All patients showed a one to seven line gain of corrected distance visual acuity.

CONCLUSIONS:

FS-LASIK was an effective method of hyperopia correction in this cohort of children with amblyopia, resulting in reduction in anisometropia, restoration of refractive balance, and functional improvement in the amblyopic eye when traditional methods failed.

[J Refract Surg. 2020;36(6):366–373.]

Abstract

PURPOSE:

To analyze clinical and functional results of femtosecond laser–assisted laser in situ keratomileusis (FSLASIK) in children with hyperopia and unilateral anisome-tropic amblyopia.

METHODS:

The study included 24 patients (24 eyes) aged 5 to 15 years. Before the surgery, the mean manifest refractive spherical equivalent (MRSE) of amblyopic eyes was +3.90 ± 1.60 diopters (D) (range: +1.50 to +6.80 D) and the mean refractive anisometropia was 3.06 ± 1.64 D (range: 0.87 to 7.50 D). Every patient had at least 1 year of ineffective traditional amblyopia treatment before surgery. The mean follow-up period was 7 years (range: 6.9 to 7.4 years).

RESULTS:

At the final follow-up visit, the mean MRSE of operated eyes was +0.41 ± 1.35 D (range: −1.13 to +3.88 D) (P < .001) and anisometropia in MRSE notation was 1.39 ± 1.15 D (range: 0.00 to 4.63 D). Postoperative spherical equivalent was within ±0.50, ±1.00, and ±2.00 D in 31%, 38%, and 92%, respectively. There were no complications. All patients showed a one to seven line gain of corrected distance visual acuity.

CONCLUSIONS:

FS-LASIK was an effective method of hyperopia correction in this cohort of children with amblyopia, resulting in reduction in anisometropia, restoration of refractive balance, and functional improvement in the amblyopic eye when traditional methods failed.

[J Refract Surg. 2020;36(6):366–373.]

Amblyopia, along with refractive errors, is one of the leading reasons for visual disability in children and adults and poses a serious medical and social problem on a global scale.1–3 Hyperopic children deserve special attention because they cannot successfully focus at any distance4 and are always at higher risk of developing amblyopia and binocular vision impairment compared to those with myopia.3,4 The prevalence of hyperopia averages 8.4% among children younger than 6 years and 2% to 3% among those 9 to 14 years, whereas among teenagers (15 years and older) it does not exceed 1%.5 Anisometropic amblyopia appears to be rather resistant to traditional therapy and, thus, the treatment has no effect in 32% of cases on average.6–10 This explains why ophthalmologists are so interested in searching for alternative methods of refractive error correction in hyperopic children, including refractive surgery. The aim of this study was to analyze the long-term clinical and functional results of unilateral femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK) in children with hyperopia and uni-lateral anisometropic amblyopia.

Patients and Methods

Patient Selection

This retrospective study included 24 patients (45.83% male, 54.17% female) who underwent surgery on one amblyopic eye during the period between 2007 and 2014. The average patient age was 8 ± 2.10 years (range: 5 to 15 years). There were 11 right eyes and 13 left eyes.

In every patient, surgery was preceded by traditional amblyopia treatment of 1 to 3 years in duration without consistent visual improvement. All interventions were performed by the same surgeon (ILK). The total follow-up period was approximately 7 years (range: 6.9 to 7.4 years). Eleven patients (45.83%) had accommodative strabismus measuring 5 to 7 degrees of deviation on Hirschberg testing. Preoperative ocular parameters are given in Table 1. Uncorrected distance visual acuity (UDVA) in the amblyopic eye scheduled for surgery was 1.07 ± 0.42 logMAR and corrected distance visual acuity (CDVA) was 0.72 ± 0.31 logMAR. The average manifest refraction spherical equivalent (MRSE) of the non-amblyopic fellow (leading) eye before surgery was +1.17 ± 0.95 diopters (D) (range: −0.75 to +3.25 D).

Preoperative and Postoperative Parameters, Mean ± SD (N = 24)

Table 1:

Preoperative and Postoperative Parameters, Mean ± SD (N = 24)

Two inclusion criteria were applied: hyperopic anisometropia of 3.00 D or greater of spherical component refraction and the ineffectiveness (> 1 year) of traditional management of amblyopia, including spectacles, contact lenses, and pleoptic treatment. The exclusion criteria were as follows: central corneal thickness less than 500 µm, keratometry of 48.00 D or greater, previous ocular surgeries, ocular comorbidity or severe somatic pathology, and age younger than 5 years. Children with previous surgery for nonaccommodative esotropia were also not included in this study.

The patients underwent a standardized ophthalmic assessment. All examinations and surgeries were performed in accordance with ethical standards of the 1975 Declaration of Helsinki and its 2000 revision. Before signing the informed consent, parents were informed of the goals and objectives of the proposed laser surgery and possible risks. Only amblyopic eyes were treated with laser. When considering the target refraction, we aimed to restore the refractive balance between the two eyes.

Surgical Technique

In children younger than 12 years (n = 23), the surgery was performed under general anesthesia with inhalational sevoflurane and fentanyl. For ventilation, laryngeal masks and artificial ventilation systems were engaged. The only patient who was older received topical anesthesia (inocaine 0.4%) with eye fixation during excimer ablation. During the FS-LASIK procedure, a corneal flap was created (9.5 to 10 mm in diameter and 110 to 120 µm in thickness) using the IntraLase FS KHz femtosecond laser (AMO). Excimer photoablation of the stroma was performed using the MicroScan 500 Hz excimer laser (Opto-Systems). With the limbus tracking system engaged, the center of the ablation zone was matched with the midpoint between the coaxially sighted corneal reflex and the center of the pupil. The central optical zone diameter was 6.5 to 6.8 mm and the total ablation zone diameter was 8.8 to 9 mm. At ablation completion, special attention was paid to repositioning of the flap and achieving the best interface. An aseptic dressing was applied for 24 hours (until the next morning), while the patient remained under close supervision of the surgeon and parents.

Postoperative therapy included antibiotics (ciprofloxacin eye drops four times daily for 7 days) and steroidal anti-inflammatory drugs (fluoromethalone eye drops for 4 weeks). Tear substitutes were prescribed for 3 months. Traditional treatment for amblyopia was provided for the next 2 to 5 years. One year postoperatively, after the refractive stabilization, well-tolerated glasses were prescribed in 100% of cases. Mean follow-up was 7 years.

Statistical Analysis

Statistical analysis was done using Statistica 10 (Stat-Soft) and Office Excel 2007 (Microsoft Corporation) software. The variables were tested for normality by the Kolmogorov–Smirnov criterion. The following indicators of descriptive statistics were used: number of cases, mean ± standard deviation, and categorical variables (percentages). To compare data before and after surgery, a paired Student's t test was used. The differences between the groups were considered significant if the P value was less than .05. The Friedman test was used to compare repeated measures in follow-up visits. Visual acuity was converted to logMAR scale from the decimal notation. The standard graphs and terms for refractive surgery results were used. The safety index was calculated as the ratio between the postoperative and preoperative CDVA and the efficacy index as the ratio between the postoperative UDVA and preoperative CDVA.

Results

No major intraoperative or postoperative complications were encountered. None of the patients developed flap-associated inflammation during the follow-up period. Postoperative corneal remodeling with consequent stabilization of refraction took 6 to 9 months. Within the first 3 to 4 months after surgery, all patients developed a temporary shift in refractive error toward myopia, which was probably due to changes in accommodation of the operated eye.

One year postoperatively, refraction of the operated eye was mostly stable in all patients. Significant changes of more than 0.50 D occurred between 3 and 7 years (range: 36 to 84 months) after surgery (Figure 1F). In general, the refractive regression over the 6 years of observation (the period from 1 to 7 years after surgery) averaged 0.90 ± 1.68 D of spherical equivalent (P = .01). The summarized data on the refractive predictability, safety, and effectiveness of the intervention, as well as the stabilization rate of the refraction parameters at 7 years after FS-LASIK, are shown in Figure 1 and Table 1. Anisometropia changes are given in Figure 2. Individual patients' data before and 7 years after FS-LASIK are presented in Tables 23.

(A) Cumulative histogram of uncorrected distance visual acuity (UDVA) before and 7 years after femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK); (B) corrected distance visual acuity (CDVA) (in lines) before and 7 years after FS-LASIK; (C) attempted versus achieved spherical equivalent refraction 7 years after FS-LASIK, scatterplot; (D) refraction prediction accuracy 7 years after FS-LASIK; (E) refractive astigmatism preoperatively and 7 years after FS-LASIK; (F) stability of spherical equivalent refraction after FS-LASIK. D = diopters

Figure 1.

(A) Cumulative histogram of uncorrected distance visual acuity (UDVA) before and 7 years after femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK); (B) corrected distance visual acuity (CDVA) (in lines) before and 7 years after FS-LASIK; (C) attempted versus achieved spherical equivalent refraction 7 years after FS-LASIK, scatterplot; (D) refraction prediction accuracy 7 years after FS-LASIK; (E) refractive astigmatism preoperatively and 7 years after FS-LASIK; (F) stability of spherical equivalent refraction after FS-LASIK. D = diopters

Manifest refraction spherical equivalent (MRSE) before and 7 years after femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK). D = diopters; SD = standard deviation

Figure 2.

Manifest refraction spherical equivalent (MRSE) before and 7 years after femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK). D = diopters; SD = standard deviation

Preoperative Clinical and Functional Characteristics of Patients (N = 24)

Table 2:

Preoperative Clinical and Functional Characteristics of Patients (N = 24)

Clinical and Functional Characteristics of Patients 7 Years After Surgery (N = 24)

Table 3:

Clinical and Functional Characteristics of Patients 7 Years After Surgery (N = 24)

Seven years after surgery, 37.5% of patients had decimal UDVA of 0.5 or better (Figure 1A). Before surgery, none of them scored that much without correction. Moreover, all patients after surgery gained one to seven lines of CDVA. The safety index was 2.17 and the efficacy efficiency index was 1.7. In children who had accommodative strabismus before surgery (11 cases), the angle of deviation decreased to 2 to 3 degrees (Hirschberg's test). As seen in Figure 1, postoperative MRSE was within ±2.00 D in 92% (Figure 1D); in the remaining 38% of cases, MRSE was within ±1.00 D. Surgically induced astigmatism ranged from −0.75 to −1.00 D in 23% of cases and from −1.25 to −1.50 D in 7% of cases (Figure 1E).

Table 1 displays the mean values of study parameters obtained after surgery. A comparison can be drawn between the leading and the amblyopic eye. One can see that the refractive data of amblyopic eyes changed significantly: MRSE decreased by 3.25 ± 1.40 D and cycloplegic spherical equivalent by 4.24 ± 1.80 D. By the end of the observation period, anisometropia (in MRSE notation) decreased on average by 1.72 ± 1.05 D (Figure 2).

The mean keratometry values increased from 42.41 ± 1.21 to 46.18 ± 1.75 D, and the maximum reading did not exceed 49.25 D. Central corneal pachymetry readings after surgery were 14.29 µm less than at baseline. The decrease in corneal thickness was 26.50 µm in the 4-mm zone and 57.04 µm in the 6-mm zone. The axial length of amblyopic eyes increased by 0.57 ± 0.32 mm (P < .001) on average. By assessing the fellow eye, we have identified a similar axial growth of 1.14 ± 0.49 mm (P < .001) over the observation period. In this study, a tendency toward myopization of the fellow eye was recorded in 30% of cases (7 eyes) with the mean MRSE of −0.04 ± 1.28 D (range: −3.88 to +2.50 D). Mean attempted refractive correction was +5.17 ± 1.54 D and the achieved correction averaged +4.78 ± 1.60 D with a mean deviation of +0.40 ± 1.41 D (Table 3).

Discussion

First attempts at excimer laser surgery in children (back in 1995) were encouraging, reporting improvement in visual acuity and avoidance of serious complications.11–25 However, the number of studies on the effectiveness of laser correction (including LASIK) in hyperopic children is currently insufficient, and there is no clear consensus on the applicability of keratorefractive surgery to pediatric practice.

In the study of Phillips et al,23 LASIK was performed in 14 hyperopic children and adolescents with mean anisometropia of 4.43 D and spherical equivalent of the amblyopic eye of +4.94 ± 1.25 D. The mean attempted refraction of +3.65 D in spherical equivalent notation deviated from 18-month results of 2.32 D by −1.33 D. No complications followed. In recent years, there have been several publications on pediatric PRK, laser-assisted subepithelial keratotomy, and LASIK26–31 that convincingly demonstrate the appropriateness of laser surgery in amblyopic patients resistant to traditional treatment.

Utine et al27 conducted a study on the effectiveness of LASIK in 32 children aged 4 to 15 years who had hyperopic anisometropia of more than +2.00 D. At 12 months, spherical equivalent was found to have decreased from +4.60 ± 2.20 to +1.39 ± 0.21 D. MRSE was within ±1.00, ±2.00, ±3.00, and ±4.00 D in 47% (15 eyes), 72.3% (23 eyes), 96.9% (31 eyes), and 100% (32 eyes), respectively. Almost all patients gained one to four lines of CDVA and only 1 patient demonstrated a one-line loss.

Some authors provided a thorough analysis of this problem29–31 and expressed strong support for refractive surgery in children. They also raised many unresolved questions concerning the effectiveness and safety of laser treatment and emphasized the need for randomized long-term trials. There is no doubt that to ensure proper development of the visual system, refractive problems need to be addressed in early childhood. Children in whom standard methods of refractive correction were ineffective should be considered for refractive surgery because the latter is the only opportunity for them to improve vision. Through continuous improvement of laser technologies and hardware, many possible complications of keratorefractive surgery in children have now been minimized. Treatment zone expansion improves overall effectiveness of the procedure and accuracy of refractive prediction, as well as reducing the decentration risk.31 We applied this principle previously evaluated in adults to pediatric cases.

The current study is the first attempt to provide long-term (7-year) results of hyperopic refractive correction in children by FS-LASIK. Our patients had no complications. Nevertheless, a thorough examination is necessary in each case, because children rarely complain of vision discomfort. Also, there has not been a single case of flap dislocation, which was often reported by other authors.27,29 As seen in Table 3, CDVA improvement was not universal despite similar baseline refractive errors. This could be partially explained by patient age differences.4,29 Another reason for low visual improvement is supposedly related to accommodative strabismus without central fixation observed prior to surgery in 11 patients.

Over the period from year 1 to year 7, average keratometry values underwent certain changes, which should be regarded as a regression of surgical effect due to tissue remodeling in the ablation zone and in the flap and epithelium.27,28 Refractive predictability in this study (±0.50 D = 31%, ±1.00 D = 38%, and ±2.00 D = 92%) was somewhat higher than that reported by Utine et al,27 which could be explained by a larger central ablation zone of 6.5 mm.

Surgically induced corneal astigmatism is one of the problems in the correction of hyperopia. In this study, it was 1.60 ± 0.83 D (range: 0.26 to 3.50 D) (Figure 1E). According to our data, postoperative astigmatism is not associated with the offset of the ablation center. More likely, the amount of astigmatism is determined by the ablation profile itself, epithelial hyperplasia, changes within the flap, eyelid pressure, and other factors. As seen in Figure 1, predictability of refractive cylinder correction in our study within ±0.50 D of the intended target achieved 23%, whereas the same measure for ±1.00 D reached 62%. Application of sophisticated optimized FS-LASIK protocols with cyclotorsion control for correction of high hyperopic cylinder (≥ 3.00 D) in adults demonstrated rather moderate effectiveness given a relatively high need for re-treatments (23.75%).32 At the same time, employment of customized aspheric ablations for the treatment of pediatric hyperopic astigmatism could offer improvements in the cylinder component of refraction. It should also be acknowledged that vector analysis and higher order aberration evaluation necessary for more accurate assessment of astigmatism correction were not included in our study, which was one of its limitations. Eventually, the primary surgical goal was achieved: anisometropia decreased, visual functions improved, and CDVA increased by one to seven lines in all cases.

In planning pediatric refractive treatment, possible future axial elongation should be considered. Refractive development after surgery over the whole follow-up period is illustrated in Figure 1F. Some refractive instability seen here did not interfere with the main objective of the surgery to allow for visual development of the amblyopic eye. At the same time, despite close monitoring and treatment, the fellow (leading) eye developed myopia in 30% of cases. In this regard, we would like to emphasize the necessity of preventive measures against myopia of the fellow eye: dynamic control by the pediatric ophthalmologist, screening diagnostic programs, adequate full-time spectacle correction, orthokeratology, and accommodative training.

Surgery is a radical measure and in the pediatric group it should be considered as a measure of last resort reserved for children in whom all other methods of functional correction have failed. Based on the latest research evidence and our own experience, we suggest that pediatric refractive surgery represents a viable treatment strategy for unilateral anisometropic amblyopia. The goals of pediatric laser refractive surgery include elimination of anisometropia and aniseikonia and creation of optimal conditions for further development of visual functions. Nonetheless, research in this area is undoubtedly needed.

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Preoperative and Postoperative Parameters, Mean ± SD (N = 24)

ParameterPreoperative1 Year Postoperative7 Years PostoperativeFriedman TestPa
UDVA of the amblyopic eye
  logMAR1.07 ± 0.42 (0.40 to 2.00)0.60 ± 0.29 (1.00 to 0.25)0.40 ± 0.30 (0.10 to 1.30)Chi-square = 27.358, P < .001
  Decimal0.12 ± 0.110.30 ± 0.170.37 ± 0.20
CDVA of the amblyopic eye
  logMAR0.72 ± 0.31 (0.05 to 1.50)0.45 ± 0.28 (0.05 to 1.00)0.30 ± 0.30 (0.05 to 1.30)Chi-square = 21.740, P < .001
  Decimal0.23 ± 0.180.43 ± 0.220.54 ± 0.27
MRSE of the amblyopic eye (D)+3.90 ± 1.60 (+1.50 to +6.80)−0.54 ± 1.21 (−2.50 to +3.125)+0.41 ± 1.35 (1.13 to +3.88)Chi-square = 36.839, P < .001
Cycloplegic refraction of the amblyopic eye (D)+4.51 ± 1.69 (+0.75 to +8.38)−0.33 ± 1.28 (−2.00 to +3.63)−0.11 ± 1.48 (−3.50 to +3.00)Chi-square = 36.280, P < .001
AL of the amblyopic eye (mm)21.53 ± 0.76 (20.40 to 23.00)22.10 ± 0.83 (20.75 to 23.61)< .001
Mean K of the amblyopic eye (D)42.41 ± 1.21 (40.50 to 45.00)46.91 ± 1.87 (43.50 to 50.25)46.18 ± 1.75 (42.50 to 49.25)Chi-square = 40.796, P < .001
Pachymetry of the amblyopic eye (µm)
  Central cornea559.08 ± 27.33 (508.00 to 640.00)529.75 ± 40.10 (408.00 to 600.00)544.79 ± 37.70 (425.00 to 627.00)Chi-square = 16.106, P < .001
  4-mm zone573.38 ± 30.80 (519.00 to 664.00)540.00 ± 38.42 (415.00 to 613.00)546.88 ± 39.77 (436.00 to 635.00)Chi-square = 13.979, P < .001
  6-mm zone628.08 ± 37.72 (552.00 to 704.00)577.96 ± 44.85 (517.00 to 683.00)571.04 ± 43.32 (490.00 to 670.00)Chi-square = 24.274, P < .001
UDVA of the fellow eye.608
  logMAR0.12 ± 0.13 (0.00 to 0.52)0.13 ± 0.29 (0.00 to 1.30)
  Decimal0.80 ± 0.200.84 ± 0.27
CDVA of the fellow eye.009
  logMAR0.07 ± 0.11 (0.00 to 0.40)0.01 ± 0.02 (0.00 to 0.10)
  Decimal0.88 ± 0.170.99 ± 0.04
MRSE of the fellow eye (D)+1.17 ± 0.95 (−0.75 to +3.25)−0.03 ± 1.29 (−3.88 to +2.50)< .001
Anisometropia in MRSE (D)3.06 ± 1.64 (0.87 to 7.50)1.39 ± 1.15 (0.00 to 4.63)< .001

Preoperative Clinical and Functional Characteristics of Patients (N = 24)

Patient/Age (y)Amblyopic Eye, Refraction (D)Fellow Eye, Refraction (D)Cycloplegic Refraction of the Amblyopic Eye (D)Anisometropia in MRSE (D)UDVA of the Amblyopic Eye (Decimal)CDVA of the Amblyopic Eye (Decimal)CDVA of the Fellow Eye (Decimal)
1/7+4.50 −1.25 × 18°+0.75 −0.25 × 140°+4.50 −0.75 × 20°3.250.40.50.9
2/8+7.00 −0.25 × 171°+3.50 −0.50 × 164°+7.25 −0.75 × 6°3.620.30.30.8
3/10+4.75 −0.75 × 48°+1.50 −0.50 × 92°+4.75 −0.75 × 55°3.120.010.030.9
4/10+5.25 −1.50 × 178°+3.50 −0.50 × 177°+5.75 −1.25 × 177°1.250.40.91
5/7+4.00 −0.50 × 14°+1.75 −1.00 × 179°+5.25 −0.25 × 8°2.500.10.20.5
6/8+5.25 −3.50 × 10°+0.50 −0.50 × 13°+5.75 −3.50 × 11°3.250.050.31
7/6+4.75 −3.00 × 58°+1.75 −0.25 × 13°+4.75 −2.50 × 63°1.620.10.31
8/9+4.00 −2.00 × 164°+1.75 −1.25 × 26°+4.75 −1.75 × 168°1.870.10.21
9/15+6.00 −1.25 × 160°0.50 0.00 × 0°+6.75 −1.25 × 167°4.870.050.11
10/6+5.25 0.00 × 0°+2.75 −0.25 × 1°+5.75 −0.25 × 167°2.620.20.21
11/7+4.50 −2.50 × 2°+3.50 −1.50 × 2°+5.50 −2.75 × 1°0.500.10.30.4
12/9+3.50 −0.25 × 176°+1.25 −0.75 × 173°+5.25 −0.75 × 5°2.500.20.31
13/7+7.25 −0.50 × 73°+1.25 −0.50 × 108°+7.25 −0.50 × 72°6.000.050.10.7
14/9+3.50 −2.00 × 179°+1.25 −0.25 × 171°+4.25 −2.00 × 175°1.370.10.21
15/7+3.00 −3.00 × 2°+0.75 −0.75 × 3°+3.75 −3.00 × 1°1.120.20.40.9
16/10+3.00 −1.00 × 8°+1.00 −0.25 × 38°+4.75 −1.25 × 14°1.620.10.21
17/6+7.00 0.00 × 0°+1.50 −0.25 × 155°+7.00 0.00 × 0°5.620.20.30.8
18/7+3.50 −0.50 × 19°+1.00 −0.25 × 172°+3.75 −0.75 × 24°2.370.050.11
19/6+6.75 −0.75 × 122°−0.50 −0.50 × 166°+7.25 0.00 × 0°6.120.050.11
20/6+5.50 −1.00 × 146°+1.25 −0.25 × 128°+6.75 −0.75 × 152°3.870.10.10.9
21/5+7.00 −0.50 × 164°+0.75 0.00 × 0°+8.75 −0.75 × 116°6.000.010.10.6
22/6+7.00 0.00 × 0°+0.75 −0.25 × 66°+7.25 −0.25 × 68°6.370.050.10.9
23/6+8.25 −0.50 × 58°+0.75 −0.25 × 79°+8.75 −0.50 × 89°7.370.050.11
24/7+5.25 −0.50 × 9°+0.75 −0.25 × 36°+5.75 −0.50 × 160°4.370.10.30.9
Mean (range)3.06 ± 1.64 (0.87 to 7.50)0.12 ± 0.11 (0.01 to 0.40)0.23 ± 0.18 (0.03 to 0.90)0.88 ± 0.17 (0.40 to 1.00)

Clinical and Functional Characteristics of Patients 7 Years After Surgery (N = 24)

PatientUDVA of the Operated Amblyopic Eye (Decimal)CDVA of the Operated Amblyopic Eye (Decimal)Attempted MRSE of the Operated Amblyopic Eye (D)Achieved MRSE of the Operated Amblyopic Eye (D)DifferenceRefraction of the Operated Amblyopic Eye (D)Refraction of the Fellow Eye (D)Anisometropia in MRSE Notation
10.70.8+3.875+3.750.13+0.50 −0.75 × 67°−1.00 −2.00 × 143°2.125
20.30.6+6.50+7.88−1.38+0.75 −3.75 × 176°+1.00 −0.50 × 83°1.875
30.060.1+5.75+6.25−0.50+0.50 −2.00 × 170°+1.00 −0.50 × 83°1.125
40.60.8+3.625+4.13−0.50+0.50 −2.00 × 24°+0.50 0.00 × 0°1.00
50.50.8+4.75+4.750.00+1.50 −2.50 × 4°+0.75 −0.75 × 4°0.13
60.50.7+4.00+4.25−0.25+0.50 −1.50 × 162°+1.25 −0.25 × 84°1.38
70.60.8+3.875+3.250.63+1.25 −1.25 × 35°−2.00 −0.50 × 106°2.875
80.150.4+3.50+4.25−0.75+0.25 −2.00 × 178°+0.75 0.00 × 0°1.50
90.30.4+6.25+6.250.00+0.75 −1.50 × 178°−0.50 −0.25 × 165°0.63
100.150.4+5.75+6.75−1.00+0.25 −2.50 × 170°+0.75 −0.50 × 98°1.50
110.80.9+4.25+4.50−0.25+1.00 −2.50 × 150°0.00 −0.50 × 174°0.00
120.50.6+5.00+3.881.13+1.75 −1.25 × 9°−0.50 −0.50 × 170°1.875
130.40.4+7.50+6.381.13+1.50 −0.75 × 110°+1.00 −0.50 × 7°0.375
140.150.15+3.125+3.63−0.50+0.75 −2.50 × 178°−0.50 −0.50 × 177°0.25
150.51.0+2.25+2.38−0.13+0.50 −1.25 × 168°−3.50 −0.75 × 50°3.755
160.20.2+5.00+4.380.63+0.75 −0.25 × 28°0.00 −0.25 × 155°0.755
170.30.4+7.00+3.133.88+4.75 −1.75 × 97°−0.50 −0.50 × 29°4.625
180.30.3+3.00+2.001.00+1.75 −1.50 × 18°+0.75 −0.75 × 30°0.62
190.40.7+6.50+7.00−0.5+0.50 −2.00 × 4°+1.00−0.25 × 172°1.25
200.10.2+7.00+7.000.00+0.75 −1.50 × 8°+0.75−0.25 × 122°0.50
210.20.4+7.25+3.753.50+4.00 −1.00 × 32°+3.00 −1.00 × 12°1.00
220.50.6+6.00+6.75−0.75+0.25 −2.00 × 165°+0.25 −0.25 × 70°0.88
230.40.4+7.00+4.003.00+3.50 −1.00 × 28°+0.25 0.00 × 0°2.75
240.31.0+5.25+4.380.88+1.25 −0.75 × 100°+0.50 −0.50 × 99°0.625
Mean ± SD (range)0.37 ± 0.20 (0.06 to 0.80)0.54 ± 0.27 (0.10 to 1.00)+5.17 ± 1.54 (+2.25 to +7.50)+4.78 ± 1.60 (+2.00 to +7.88)0.40 ± 1.41 (−1.38 to 3.81)1.39 ± 1.15 (0.00 to 4.63)
Authors

From The S. Fyodorov Eye Microsurgery Federal State Institution, The Cheboksary Branch, Cheboksary, Russian Federation (ILK, NPP, YNB, SMP; AET); The Postgraduate Doctors' Training Institute, Cheboksary, Russian Federation (NPP); and The Chuvash State University, Cheboksary, Russian Federation (NPP).

The authors have no financial or proprietary interest in the materials presented herein.

AUTHOR CONTRIBUTIONS

Study concept and design (ILK, NPP); data collection (ILK, YNB, SMP, AET); analysis and interpretation of data (ILK, SMP, AET); writing the manuscript (ILK, SMP, AET); critical revision of the manuscript (ILK, NPP, YNB, SMP, AET); statistical expertise (ILK, NPP, YNB, SMP)

Correspondence: Svetlana Mikha'lovna Pikusova, MD, Laser Refractive Surgery Department, S. Fyodorov Eye Microsurgery Federal State Institution, The Cheboksary Branch, Ministry of Health of the Russian Federation, 10 Traktostroiteley pr., Cheboksary 428028, Russian Federation. Email: pikusova_svetlana@mail.ru

Received: December 30, 2019
Accepted: April 14, 2020

10.3928/1081597X-20200416-02

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