Managing Pseudophakic Corneal Edema: Structural Changes and Preliminary Observations on Coenzyme Q10 Use

Abstract

Purpose

Pseudophakic corneal edema (PCE) remains a significant postoperative challenge despite advancements in cataract surgery, often delaying visual recovery and affecting refractive outcomes. This study investigates the relationship between keratometric and pachymetric changes during PCE resolution, evaluates factors influencing this process, and examines the efficacy of coenzyme Q10 (CoQ10) as an adjunct therapy.

Methods

A retrospective study was conducted on 88 patients aged 50 years and older who developed PCE after uneventful phacoemulsification. Corneal assessments were performed using Pentacam HR, focusing on keratometric and pachymetric changes. Patients were monitored weekly until PCE resolution, defined as a return of central corneal thickness within ±30 μm of preoperative values. Patients received standard postoperative treatment, with a subset also receiving CoQ10 as an adjunct therapy.

Results

Postoperative visual acuity improved significantly (p < 0.001). Despite pachymetric normalization, persistent keratometric changes were observed, particularly a steepening of posterior curvature (p < 0.001) and increased anterior asphericity (p = 0.047). CoQ10-treated patients exhibited faster edema resolution (p = 0.019), greater reduction in corneal thickness (p = 0.003), and improved transparency. Higher cumulative dissipated energy correlated with increased edema severity (r = 0.419, p < 0.001) and higher cumulative dissipated energy was linked to slower recovery times. Patients with diabetes had a prolonged recovery period compared to nondiabetic patients (p = 0.018), though pachymetric recovery rates were similar. The pachymetric progression index was unreliable in edematous corneas.

Conclusions

While visual acuity and pachymetry improved in all patients, persistent topographic changes suggest incomplete structural normalization. Preliminary findings indicate that adjunctive CoQ10 use may support more efficient corneal edema resolution, as evidenced by faster recovery and favorable structural changes. Further prospective studies are warranted to confirm these observations.

Cataract is the leading cause of preventable blindness worldwide, and while advances in cataract surgery have significantly improved patient outcomes, postoperative corneal edema (PCE) remains a major obstacle to timely visual recovery [1]. This condition, often temporary after phacoemulsification, can result from endothelial cell damage, inflammation, or preexisting conditions like diabetes, negatively impacting both visual acuity (VA) and quality of life. Although temporary in most cases, the management of PCE, particularly regarding the timing for spectacle prescription, remains poorly defined [2,3]. The advent of advanced imaging techniques like the Pentacam (Oculus), which provides detailed three-dimensional corneal analysis, offers a more reliable approach to evaluating and monitoring postoperative corneal edema compared to traditional methods such as specular microscopy [4].

Coenzyme Q10 (CoQ10) is a mitochondrial cofactor with potent antioxidant properties, increasingly recognized for its protective effects on ocular tissues. In the context of cataract surgery, oxidative stress from phacoemulsification may impair corneal endothelial function, contributing to postoperative edema. [5]. Beyond the endothelium, CoQ10 has been shown to facilitate epithelial regeneration by enhancing cellular proliferation and migration [6], while also supporting tear film stability through anti-inflammatory mechanisms [7]. These multifaceted actions suggest that CoQ10 may serve as a valuable adjunct in promoting corneal recovery and ocular surface integrity following intraocular surgery.

This study aims to improve understanding of the postoperative recovery process in corneal edema by analyzing pachymetric and keratometric changes after phacoemulsification, and to evaluate the potential adjunctive role of topical CoQ10 in supporting corneal structural restoration.

Materials and Methods

Ethics statement

This retrospective study was approved by the Institutional Review Board of Ankara Training and Research Hospital (No. E-23-1244). Informed consent for publication of the research details and clinical images was obtained from the patients. All procedures were conducted in accordance with the Declaration of Helsinki.

Inclusion criteria

Patients aged 50 years and older who underwent uneventful phacoemulsification with intraocular lens implantation between 2019 and 2022 were included.

Exclusion criteria

Patients with prior ocular surgeries, systemic diseases (except diabetes), corneal pathologies, retinopathy, or uveitis were excluded.

Participant data

We recorded demographic data, systemic conditions, medical history, and cataract stages from stage 2 to 4. Cataract stages were recorded using the Lens Opacities Classification System II (LOCS II), as per the institutional protocol at the time of evaluation [8].

Surgical protocol

All surgeries followed a standardized procedure with a 2.4-mm superior clear corneal incision, using 0.5% proparacaine for anesthesia. Phacoemulsification in torsional mode was performed via the stop-and-chop technique, and foldable acrylic lenses (Acrysof SA60AT, Alcon Laboratories) were implanted. Cumulative dissipated energy (CDE) was monitored. Postoperatively, patients received 0.1 mL intracameral cefuroxime and topical medications including 1 mg/mL nepafenac, 1 mg/mL dexamethasone, and 0.5% moxifloxacin, with optional CoQ10.

CoQ10 use

In this retrospective cohort, the use of topical CoQ10 and vitamin E (Coqun, Visufarma) was not part of a standardized postoperative protocol but was recommended at the discretion of the attending clinician. Patients who agreed to use the product were instructed to instill one drop four times daily beginning on the first postoperative day and to continue for approximately 4 weeks. The formulation contains 0.1% CoQ10 combined with vitamin E tocopheryl polyethylene glycol succinate, which serves as a lipophilic carrier to enhance corneal penetration. Patients were advised on proper instillation technique, and adherence was assessed indirectly through follow-up visit interviews and clinical observation.

Subgroup analysis

As part of an exploratory analysis, patients were also stratified based on diabetic status to examine whether diabetes mellitus (DM), a known risk factor for delayed corneal healing, influenced the resolution of PCE. This comparison was conducted to characterize potential variability in recovery time and structural parameters. No adjustments were made for confounding variables due to the descriptive nature of this subgroup analysis.

Patients’ evaluation

Primary outcomes were defined as early postoperative corneal edema, assessed by corneal transparency and central corneal thickness, with or without Descemet membrane folds, 2 hours after surgery [1]. All evaluations were conducted from 9 am to 12 pm, encompassing best-corrected VA via the Snellen chart, comprehensive anterior and posterior segment examinations, adjusted intraocular pressure (IOP) for pachymetry, and detailed macula and optic disk assessments.

Pentacam analysis

Pentacam HR (Oculus Inc) was used for comprehensive corneal topographic analysis. Key parameters included keratometry of the flattest and steepest meridians, displacement of the thinnest corneal point, anterior chamber depth, and the minimum radius of curvature. Asphericity for both the anterior and posterior surfaces were recorded to assess corneal shape. Other metrics such as index of surface variance (ISV) and index of height asymmetry were analyzed to assess corneal geometry.

Corneal thickness and pachymetry

Corneal thickness was measured at the thinnest location (thinnest corneal thickness, TCT), apex (pachy apex thickness, PAT), and pupil center (pupil center thickness, PCT). The pachymetric progression index (PPI) was calculated to assess average progression across different zones.

Corneal volume and densitometry

Corneal volume (CV) and corneal densitometry (CD) were measured at four key zones (3, 5, 7, and 10 mm), with densitometry quantified in grayscale units to track transparency.

Follow-up

All patients were evaluated on postoperative day 1 and then followed on a weekly basis until corneal edema resolved. Resolution was defined as central corneal thickness returning to within ±30 μm of the preoperative value. Due to the variable duration of edema among patients, the “final” follow-up time point used in the analysis represents the individualized visit at which this resolution criterion was met. Intermediate values were not consistently included in the statistical comparison to ensure uniformity in the analysis.

Statistical analysis

Statistical analyses were performed using SPSS ver. 21 (IBM Corp). The normality of the distribution of variables was assessed using visual (histograms and probability plots) and analytical methods (Kolmogorov-Smirnov tests). Descriptive statistics were presented using mean and standard deviation for normally distributed variables, median and interquartile range (IQR) for non-normally distributed variables, and frequency tables for categorical variables. Independent samples t-tests were used for group comparisons of normally distributed variables, and Mann-Whitney U-tests were used for comparisons of non-normally distributed groups. Paired t-tests were used for comparisons of dependent groups with normal distribution, and Wilcoxon tests were used for comparisons of non-normally distributed dependent groups. For comparisons of more than two dependent groups, repeated measures analysis of variance was used for normally distributed variables (with sphericity assumed if p-value for sphericity was significant, and Greenhouse-Geisser correction applied otherwise), and Friedman test was used for non-normally distributed variables (with post hoc analyses conducted using Wilcoxon tests and Bonferroni correction applied to p-values). Pearson test was used to calculate correlation coefficients and statistical significance for normally distributed variables, while Spearman test was used for variables with at least one non-normally distributed variable. A type I error level of 5% was used for statistical significance.

Results

Baseline characteristics and study population

A total of 88 eyes from 88 participants (age, 71.02 ± 7.74 years) were analyzed. Cataract stages were distributed as follows: 51 patients (58.0%) in stage 2, 19 patients (21.6%) in stage 3, and 18 patients (20.5%) in stage 4. CoQ10 was used by 39 patients (44.3%), and 36 patients (40.9%) had DM. The average CDE during surgery was 14.69 ± 5.58 percent-seconds (Table 1). Postoperative biomicroscopic examinations confirmed the absence of complications such as epithelial defects, incision leaks or Descemet membrane detachment in all cases. IOP before surgery averaged 13.76 ± 3.56 mmHg, and no patient required additional treatment for postoperative IOP elevation, suggesting that neither elevated IOP nor epithelial compromise contributed significantly to corneal edema in this cohort.

Table 1.

Patient demographics and baseline characteristics

Characteristic	Overall (n = 88)	Coenzyme Q10 group (n = 39)	Standard treatment group (n = 49)	p-value
Age (yr)	71.02 ± 7.74	72.1 ± 7.1	69.9 ± 8.2	0.348
Cataract stage
Stage 2	51 (58.0)	24 (61.5)	27 (55.1)	0.574
Stage 3	19 (21.6)	8 (20.5)	11 (22.7)	0.765
Stage 4	18 (20.5)	7 (18.0)	11 (22.4)	0.829
Diabetes mellitus	36 (40.9)	17 (43.6)	19 (39.8)	0.732
Cumulative dissipated energy (percent-seconds)	14.69 ± 5.58	15.0 ± 6.1	14.4 ± 5.1	0.532
Visual acuity (logMAR)
Preoperative	0.70 ± 1.00	0.71 ± 0.09	0.68 ± 0.08	0.441
Postoperative (final follow-up)	0.10 ± 0.05	0.12 ± 0.04	0.11 ± 0.03	0.230

Values are presented as mean ± standard deviation or number (%). Comparisons between groups were made using independent t-tests for normally distributed variables and Mann-Whitney U-tests for non-normally distributed data.

logMAR = logarithm of the minimum angle of resolution.

VA and edema recovery outcomes

VA improved significantly in all patients, from a baseline of 0.70 ± 1.00 to 0.10 ± 0.05 logarithm of the minimum angle of resolution (logMAR) at final follow-up (Table 1). No statistically significant difference in final VA was observed between the CoQ10 group and the standard treatment group (0.12 ± 0.04 logMAR vs. 0.11 ± 0.03 logMAR, p = 0.856) (Table 2).

Table 2.

Coenzyme Q10 group versus standard treatment group

Parameter	Coenzyme Q10 group (n = 39)	Standard treatment group (n = 49)	p-value
Thinnest corneal thickness (μm)
Postoperative day 1	674.16 ± 64.07	627.94 ± 78.63	0.004*
Final follow-up	541.18 ± 38.47	533.08 ± 39.82	0.344
Change	131.00 ± 23.91	86.00 ± 19.89	0.003*
Corneal volume change (mm3)	109.00 ± 19.60	95.00 ± 21.70	0.032*
Posterior steep keratometry change (D)	−0.42 ± 0.34	−0.34 ± 0.41	0.003*
Posterior asphericity change	−0.017 ± 0.020	−0.009 ± 0.018	0.047*
Visual acuity (logMAR)
Postoperative day 1	0.70 ± 1.00	0.40 ± 0.78	0.098
Final follow-up	0.12 ± 0.04	0.11 ± 0.03	0.856
Change (improvement)	0.59 ± 0.15	0.57 ± 0.16	0.230
Recovery time (wk)	2 (1–3)	4 (2–5)	0.019*
Age (yr)	72.43 ± 6.82	69.81 ± 8.35	0.126

Values are presented as mean ± standard deviation or median (interquartile range). The “change” values represent the difference between postoperative day 1 and the final follow-up, Paired t-tests were used to compare changes between postoperative day 1 and the final follow-up for normally distributed variables, while Wilcoxon signed-rank tests were applied for non-normally distributed variables.

Recovery time was compared using Mann-Whitney U-tests.

D = diopters; logMAR = logarithm of the minimum angle of resolution.

^*Statistically significant ( p < 0.05).

The median recovery time from corneal edema was 2 weeks (IQR, 1–5 weeks) in the entire cohort. However, when stratified by treatment group, the CoQ10 group demonstrated significantly faster recovery (median, 2 weeks; IQR, 1–3 weeks) compared to the standard group (median, 4 weeks; IQR, 2–5 weeks; p = 0.019) (Table 2).

Pachymetric and volumetric changes

Corneal thickness parameters (TCT, PCT, PAT), CV, and anterior stromal CD increased initially after surgery but decreased significantly by the final follow-up. For example, TCT increased from 536.42 ± 39.15 μm preoperatively to 647.08 ± 75.96 μm on postoperative day 1, and then decreased to 541.18 ± 38.47 μm at final follow-up (p < 0.001). Similarly, CV decreased from 723.8 ± 66.6 mm³ on the first postoperative day to 616.2 ± 55.9 mm³ at final follow-up (p < 0.001) (Table 3). Displacement of the thinnest corneal point was significant on the y-axis (p < 0.001) but not on the x-axis (p = 0.348).

Table 3.

Corneal thickness, volume, and topographic changes

Parameter	Preoperative (A)	Postoperative day 1 (B)	Final follow-up (C)	p-value (A vs. B)	p-value (B vs. C)
Thinnest corneal thickness (μm)	536.42 ± 39.15	647.08 ± 75.96	541.18 ± 38.47	<0.001*	<0.001*
Pupil center thickness (μm)	520.30 ± 42.25	638.12 ± 68.57	525.60 ± 40.14	<0.001*	<0.001*
Pachy apex thickness (μm)	550.22 ± 36.35	665.45 ± 72.10	555.12 ± 35.88	<0.001*	<0.001*
Corneal volume (mm3)	616.4 ± 57.7	723.8 ± 66.6	616.2 ± 55.9	<0.001*	<0.001*
Anterior steep keratometry (D)	44.74 ± 1.77	44.87 ± 2.33	44.89 ± 2.30	0.918	0.597
Posterior steep keratometry (D)	−6.39 ± 1.45	−7.01 ± 0.66	−6.55 ± 1.23	<0.001*	<0.001*
Anterior asphericity	−0.42 ± 0.33	−0.30 ± 0.55	−0.31 ± 0.42	0.047*	0.872
Posterior asphericity	−0.042 ± 0.033	−0.013 ± 0.068	−0.030 ± 0.055	0.014*	0.047*
Index of surface variance	279.6 ± 128.7	329.2 ± 129.7	287.4 ± 118.4	<0.001*	0.103
Index of vertical asymmetry	0.25 ± 0.14	0.30 ± 0.14	0.27 ± 0.12	<0.001*	0.065

Values are presented as mean ± standard deviation. Paired t-tests were used for comparisons of preoperative and postoperative values for normally distributed variables, while Wilcoxon signed-rank tests were used for non-normally distributed variables.

D = diopters.

^*Statistically significant ( p < 0.05).

PPI values could not be reliably assessed in corneas with edema, as measurement errors were common. While there was no significant difference in PPI values before and after treatment, the maximum PPI decreased from 1.25 ± 0.36 to 1.16 ± 0.31 by the final follow-up (p = 0.083). Fig. 1A–1D demonstrates the distribution of PPI values.

Fig. 1.

Analysis of the pachymetric progression index. (A, B) In patients with pseudophakic corneal edema, it is shown that measurements could not be obtained from all areas due to edema, resulting in unreliable data beyond a certain point (indicated by a red arrow line). Beyond this, no further data could be recorded (indicated by a black arrow line). (C, D) In contrast, in healthy corneas, measurements were consistently obtained within the expected range, demonstrating complete and reliable data acquisition.

Keratometric and topographic remodeling

Significant changes in corneal shape were observed during edema resolution. Anterior steep keratometry values changed slightly from 44.87 ± 2.33 diopters (D) on postoperative day 1 to 44.89 ± 2.30 D at final follow-up, though this change was not statistically significant (p = 0.597). Posterior steep keratometry increased from −6.39 ± 1.45 D preoperatively to −7.01 ± 0.66 D on postoperative day 1 (p < 0.001), then partially returned toward baseline at final follow-up (−6.55 ± 1.23 D, p < 0.001). Posterior asphericity also increased significantly from −0.013 ± 0.068 on postoperative day 1 to −0.030 ± 0.055 during follow-up (p = 0.047), indicating remodeling of the posterior surface. Additionally, topographic irregularity indices such as the ISV and index of vertical asymmetry (IVA) increased from 279.6 ± 128.7 preoperatively to 329.2 ± 129.7 on postoperative day 1 and from 0.25 ± 0.14 preoperatively to 0.30 ± 0.14 on postoperative day 1, respectively (both p < 0.001), reflecting transient corneal irregularity during the edema phase (Table 3).

CoQ10 as an adjunct: comparative outcomes

A comparative analysis between the CoQ10 and standard treatment groups is presented in Table 2. The CoQ10 group exhibited a significantly greater reduction in TCT (131.00 ± 23.91 μm vs. 86.00 ± 19.89 μm, p = 0.003) and CV (109.00 ± 19.60 mm³ vs. 95.00 ± 21.70 mm³, p = 0.032) from the first postoperative day to final follow-up. Additionally, posterior steep keratometry and posterior asphericity showed significantly greater changes in the CoQ10 group ( p = 0.003 and p = 0.047, respectively), suggesting enhanced remodeling of the posterior corneal surface.

Despite similar baseline VA and age distributions, the median recovery time was significantly shorter in the CoQ10 group (2 weeks vs. 4 weeks, p = 0.019), further supporting the hypothesis of more efficient corneal recovery. (Tables 1, 2 and Fig. 2).

Fig. 2.

Analysis of thinnest corneal thickness changes across treatment groups.

Influence of DM

Comparing the DM and non-DM groups, the only statistically significant difference observed was in recovery time, which was shorter in the non-DM group (p = 0.018) (Table 4). No statistically significant differences were found between the groups in terms of CV reduction or other thickness parameters.

Table 4.

Comparison between patients with and without DM

Parameter	With DM (n = 36)	Without DM (n = 52)	p-value
Thinnest corneal thickness (μm)
Final follow-up	536.42 ± 39.15	538.50 ± 38.90	0.344
Change	118.00 ± 24.30	125.00 ± 26.18	0.508
Corneal volume (mm3)
Final follow-up	616.4 ± 57.7	618.2 ± 55.8	0.100
Change	108.00 ± 22.12	112.00 ± 20.75	0.432
Posterior steep keratometry change (D)	−0.37 ± 0.36	−0.43 ± 0.40	0.318
Posterior asphericity change	−0.015 ± 0.020	−0.018 ± 0.021	0.508
Visual acuity improvement (logMAR)	0.58 ± 0.15	0.60 ± 0.16	0.768
Recovery time (wk)	4 (3–6)	3 (2–4)	0.018*

Values are presented as mean ± standard deviation or median (interquartile range). The “change” values represent the difference between the first postoperative day and the final follow-up. Independent t-tests were used for comparing final values and changes between the first postoperative day and the final follow-up for normally distributed variables, while Mann-Whitney U-tests were used for non-normally distributed data. Recovery time was also compared using Mann-Whitney U-tests.

DM = diabetes mellitus; D = diopters; logMAR = logarithm of the minimum angle of resolution.

^*Statistically significant (p < 0.05).

Correlations

In addition to the previously described findings, we expanded our correlation analysis to explore the association between intraoperative energy parameters and structural changes in the cornea. A significant positive correlation was found between CDE and TCT on postoperative day 1 (r = 0.419, p < 0.001), suggesting that higher surgical energy output is associated with greater initial corneal edema. Similarly, posterior keratometry demonstrated strong correlations with both PCT on the first postoperative day (r = 0.483, p < 0.001) and at final follow-up (r = 0.418, p < 0.001), indicating that posterior curvature changes are closely linked to corneal thickness dynamics during the resolution phase of edema. A modest negative correlation was also noted between posterior asphericity and final CV (r = −0.277, p = 0.010), potentially reflecting structural remodeling (Table 5).

Table 5.

Significant correlations between pachymetric and topographic parameters

Variable	r	p-value
CDE and TCT
Postoperative day 1	0.419	<0.001*
Final follow-up	0.231	0.030*
Posterior steep keratometry and PCT
Postoperative day 1	0.483	<0.001*
Final follow-up	0.418	<0.001*
Posterior asphericity and CV (final follow-up)	−0.277	0.010*
TCT (postoperative day 1) and cataract grade	0.272	0.010*
CV (postoperative day 1) and preoperative VA	−0.235	0.023*
TCT (final follow-up) and preoperative VA	−0.123	0.308

Pearson correlation coefficients were calculated for normally distributed variables, and Spearman rank correlation coefficients were used for non-normally distributed variables.

CDE = cumulative dissipated energy; TCT = thinnest corneal thickness; PCT = pupil center thickness; CV = corneal volumne; VA = visual acuity.

^*Statistically significant (p < 0.05).

Discussion

This study aimed to evaluate the resolution of PCE by examining changes in corneal thickness, volume, and topography as structural markers of recovery following phacoemulsification. Rather than focusing on endothelial cell count—which was unavailable due to the retrospective design—we employed indirect parameters, such as pachymetric normalization, CV reduction, and keratometric stability, to assess the extent and efficiency of edema resolution. Within this framework, we also sought to explore whether topical CoQ10, used in a subset of patients, was associated with enhanced structural recovery and shorter clinical recovery time.

While VA improved for all patients, significant topographic changes persisted. This suggests that although VA improves, it may not fully reflect changes in visual quality due to persistent corneal curvature alterations that affect overall visual function. Similar trends have been noted in conditions like Fuchs endothelial dystrophy (FED), where posterior curvature changes contribute to compromised vision [3].

Initially, postoperative increases in corneal thickness were observed, but these typically decreased over time as the edema resolved, confirming its temporary nature [9]. However, despite the reversal of thickness parameters, some topographic changes, particularly in corneal curvature, persisted.

Our study identified significant changes in corneal asphericity and posterior curvature, which play a crucial role in postsurgical visual quality [10]. The flattening of the anterior cornea and steepening of the posterior cornea led to refractive changes, particularly an increase in total corneal power [11]. These alterations, especially in the posterior curvature, highlight the posterior cornea’s greater susceptibility to edema compared to the anterior stroma [12]. As the posterior asphericity and radius of curvature decreased, the potential for hyperopic overcorrections became more evident, highlighting the importance of managing these alterations carefully to optimize refractive outcomes [13]. Persistent corneal irregularities, reflected in the increased ISV and IVA, further underscore the need for precise monitoring even after clinical resolution of the edema, as these subtle irregularities can impact final visual quality [14].

Our investigation into the PPI revealed its limitations in evaluating PCE, particularly in cases of severe edema, due to unreliable measurement patterns on Pentacam tomography [15,16].

CV peaked on the first postoperative day, indicating generalized edema rather than localized changes, which differs from conditions like FED [17]. By the final follow-up, CV remained elevated compared to preoperative levels. This suggests that follow-up may have ended before the CV could fully return to baseline, even though the clinical resolution of edema was deemed sufficient.

CD is a useful tool for tracking changes in corneal transparency caused by edema or inflammation [18,19]. In our study, CD detected changes that were not visible through standard biomicroscopy. Following surgery, we observed a significant increase in CD, reflecting reduced corneal transparency due to edema. Over time, as the edema resolved, CD values dropped, indicating a return to clearer corneal conditions [20]. These findings align with previous research by Ishikawa et al. [20], confirming that CD can effectively monitor subtle changes in the cornea that may be missed during routine clinical examinations. Interestingly, it was observed that these changes persisted even when VA had reached optimal levels at these times.

We observed a significant inferonasal shift in TCT at the peak of edema. This finding aligns with Sun et al. [21]’s observations of inferior migration of TCT and suggests that this may result from the surgical technique, which predominantly targets the superior quadrant. This indicates a potential link between surgical approach and the spatial distribution of corneal edema postoperatively.

Our study found a significant positive correlation between corneal thickness and posterior curvature during peak edema, indicating that edema severity directly affects corneal shape changes. This finding is consistent with Nowinska et al. [13], who reported that patients with FED exhibit higher posterior keratometry values due to thicker corneas.

Although the CoQ10 group exhibited higher corneal thickness values on the first postoperative day, the greater reduction in pachymetry over time cannot be solely explained by these initial differences. This reduction was accompanied by significant changes in posterior corneal curvature and asphericity—specifically, greater improvement in posterior steep keratometry and posterior asphericity values—suggesting a more comprehensive structural recovery of the cornea. Notably, despite presenting with more pronounced edema initially, patients in the CoQ10 group achieved clinical resolution in a significantly shorter time. These findings collectively support the notion that CoQ10 may play a beneficial role in enhancing corneal remodeling and accelerating the resolution of edema, rather than reflecting a simple regression to the mean. Known for its powerful antioxidant and anti-inflammatory properties, CoQ10 likely played a crucial role in enhancing corneal healing by reducing oxidative stress and inflammation [6,22]. These promising results suggest that CoQ10 could be a valuable adjunct therapy in postsurgical recovery, potentially improving both the speed and quality of visual outcomes. While this study suggests a possible association between topical CoQ10 use and corneal recovery, we emphasize that the evidence remains preliminary, and the findings should be interpreted in light of the exploratory nature of the intervention.

Our research also assessed the impact of DM, a common comorbidity in cataract patients, on corneal endothelial function and edema resolution. Contrary to prior studies suggesting prolonged recovery in diabetic patients due to compromised endothelial function, we did not find a significant correlation between DM and prolonged edema resolution [23]. However, a subtle difference in CV reduction was noted, suggesting slower edema resolution in DM patients.

CDE is a critical factor in cataract surgery, as higher CDE values are associated with increased corneal endothelial cell loss [24]. Our expanded correlation analysis offers additional insights into the relationship between surgical parameters and edema severity. The observed strong correlation between CDE and TCT on postoperative day 1 indicates that the amount of energy delivered during phacoemulsification significantly influences the degree of corneal swelling. This supports previous literature indicating that endothelial stress during surgery plays a key role in postoperative corneal changes [24]. Moreover, the correlations between posterior keratometry and pachymetric values reinforce the posterior cornea’s sensitivity to edema and its potential utility as a structural marker for both severity and recovery. These findings support our use of combined pachymetric and topographic parameters in evaluating corneal edema resolution and suggest that posterior curvature dynamics could serve as adjunctive indicators of healing progression.

This study has several limitations, including its retrospective design, relatively small sample size, absence of a control group, and lack of corneal endothelial cell density (ECD) measurements. While previous research has shown that low ECD may increase the risk of postoperative corneal decompensation, there is currently no consistent correlation between baseline ECD and postoperative cell loss [25]. Moreover, our primary aim was to evaluate postoperative pachymetric and topographic changes as indirect markers of corneal edema, rather than to directly assess endothelial cell morphology. Due to the retrospective nature of the study and the absence of uniform specular microscopy data, ECD analysis was not feasible. Future prospective studies incorporating specular microscopy could help clarify the relationship between endothelial status and corneal recovery. Other unexamined factors, such as specific phacoemulsification techniques and ultrasound energy used, may also impact our results. As the use of Coqun (VISUfarma) was based on clinician recommendation and patient acceptance rather than random assignment, potential selection bias may influence the interpretation of its therapeutic effect. Furthermore, the use of CoQ10 for PCE is not yet supported by strong clinical trial data, and our findings should be considered hypothesis-generating. Although our study included a subgroup analysis comparing diabetic and nondiabetic patients, we acknowledge that this evaluation was descriptive and not designed to assess causality. Diabetes has been previously associated with altered corneal healing and endothelial dysfunction, which may impact postoperative outcomes. However, we did not control for potential confounding factors such as surgical time, cumulative energy, or baseline corneal status, which may also influence the resolution of corneal edema. Finally, we did not assess potential tear film instability, which may have influenced some measurements.

Our study provides insights into the complex relationship between corneal edema, topographic changes, and visual recovery after phacoemulsification and intraocular lens implantation. While CoQ10 appears promising in reducing edema, more research is necessary to explore its therapeutic potential. Persistent corneal curvature changes after edema resolution suggest that careful postoperative monitoring is essential for optimizing refractive outcomes, especially in diabetic patients and those requiring higher CDE during surgery.