Alterations in corneal epithelial thickness in patients with congenital myogenic eyelid ptosis

Corneal Epithelial Thickness Mapping: A Major Review

The corneal epithelium (CE) is the outermost layer of the cornea with constant turnover, relative stability, remarkable plasticity, and compensatory properties to mask alterations in the underlying stroma. The advent of quantitative imaging modalities capable of producing epithelial thickness mapping (ETM) has made it possible to characterize better the different patterns of epithelial remodeling. In this comprehensive synthesis, we reviewed all available data on ETM with different methods, including very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) in normal individuals, corneal or systemic diseases, and corneal surgical scenarios. We excluded OCT studies that manually measured the corneal epithelial thickness (CET) (e.g., by digital calipers) or the CE (e.g., by confocal scanning or handheld pachymeters). A comparison of different CET measuring technologies and devices capable of producing thickness maps is provided. Normative data on CET and the possible effects of gender, aging, diurnal changes, refraction, and intraocular pressure are discussed. We also reviewed ETM data in several corneal disorders, including keratoconus, corneal dystrophies, recurrent epithelial erosion, herpes keratitis, keratoplasty, bullous keratopathy, carcinoma in situ, pterygium, and limbal stem cell deficiency. The available data on the potential role of ETM in indicating refractive surgeries, planning the procedure, and assessing postoperative changes are reviewed. Alterations in ETM in systemic and ocular conditions such as eyelid abnormalities and dry eye disease and the effects of contact lenses, topical medications, and cataract surgery on the ETM profile are discussed.

Influence of Upper Eyelid Surgeries on Corneal Morphology Detected with Pentacam

PURPOSE

To analyze the corneal morphological parameters before and one month after the upper eyelid (UE) blepharoplasty and external levator resection (ELR) for ptosis surgery.

MATERIALS AND METHODS

Seventy eyes of 70 patients with dermatochalasis (50 eyes) and acquired aponeurotic ptosis (AAP) (20 eyes) included in this prospective study. Detailed ophthalmologic examination was performed including the best corrected visual acuity (BCVA), slit lamp examination and dilated fundoscopy. Measurements were made before and one month after the surgeries using Pentacam. Central corneal thickness (CCT), pupil center pachymetry (PCP) and thinnest pachymetry (TP), cornea front astigmatism (AST), flat keratometry (K1), steep keratometry (K2) and mean keratometry (Km) values were evaluated.

RESULTS

Higher postoperative Km measurements were observed in dermatochalasis (p = 0.038) patients. Postoperative AST values were significantly lower in both dermatochalasis and ptosis cases (p = 0.034, p = 0.003, respectively). Increased PCP and TP were found in the AAP patients (p = 0.014, p = 0.015, respectively).

DISCUSSION

UE blepharoplasty and ELR surgeries both lead to some significant changes on corneal structure post-operatively.

LEVEL OF EVIDENCE IV

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Clinical observations of corneal topographic and tomographic changes in congenital ptosis eyes: a study in China

PURPOSE

To investigate the impact of drooping eyelid on corneal topographic and tomographic alterations in congenital ptosis eyes.

METHODS

Seventeen Chinese patients with unilateral congenital ptosis were included in this observational study. Ptosis eyes were included in the ptosis group, while normal contralateral eyes were included in the control group. The marginal reflex distance (MRD) was used to evaluate the severity of ptosis. Topographic and tomographic parameters measured by Pentacam, including keratometric, pachymetric, volumetric parameters as well as topometric indexes and D indexes, were recorded and compared between the ptosis group and the control group. Furthermore, correlation analyses were made between MRD and all measured corneal parameters.

RESULTS

The value of anterior K1, Km and posterior K2, Km was significantly decreased in the ptosis eyes (p < 0.05). Corneal thickness at the pupil center point and thinnest point was significantly thicker in ptosis group compared with the ones in control group (p < 0.05). Higher ISV, IVA, KI, IHD values were observed in ptosis eyes (p < 0.05). The intergroup difference in MRD showed significant correlation with the difference in ISV (p < 0.05).

CONCLUSION

The whole corneal contour is remodeled to be "flatter" in ptosis eyes. The upper eyelid position was closely associated with the corneal irregularity in ptosis eyes. The reasons for the discrepancy in corneal topography and tomography between ptotic and normal eyes were complicated.

Evaluation of the Effect of Dermatochalasis and Upper Eyelid Blepharoplasty Surgery on Corneal Epithelial Thickness Alterations

BACKGROUND

The aim of this study was to assess the effect of different grades of dermatochalasis (DC) and upper eyelid blepharoplasty (UEB) surgery on corneal epithelial thickness (CET), objectively using anterior segment-optical coherence tomography (AS-OCT) measurements.

METHODS

90 eyes of patients with DC were divided into three groups according to the severity of the DC. Forty-one eyes of age and sex-matched patients without DC were randomly selected as the control group. The study did not include patients with more than 2 D of spherical refractive error and more than 1.5 D of astigmatism, a history of previous eyelid surgery, ocular surface disease, contact lens use, and ophthalmic eye drop use. CET measurements of all the patients were performed with an AS-OCT (RTVue-XR, Optovue Inc., USA).

RESULTS

There were statistically significant differences in the CET of the superior, superonasal, superotemporal, inferotemporal, and temporal sectors between the DC and control groups (p = 0.001, p = 0.02, p = 0.03, p = 0.02, p = 0.04, respectively). While there were no differences in CET among the sectors of the control group, there was a difference in CET among some sectors of the DC group. When the DC group was subdivided by severity, there was no difference between subgroups for CET across all sectors both preoperatively and postoperatively. In the measurements made 6 months after UEB surgery, the CET in all sectors increased statistically significantly compared to those measured in the preoperative period.

CONCLUSION

This study revealed that DC reshaped the corneal epithelium and UEB surgery restored this remodeling 6 months after surgery.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .