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DE-102024210757-A1 - Devices and methods for detecting the presence of an epithelial layer

DE102024210757A1DE 102024210757 A1DE102024210757 A1DE 102024210757A1DE-102024210757-A1

Abstract

This disclosure relates to devices (1) and computer-implemented methods for detecting the presence of an epithelial layer (101) of an eye (100), which enhance solutions from the prior art. The device (1) for detecting the presence of an epithelial layer (101) of an eye (100) comprises an illumination unit (7) configured to shine illumination light (9) into a processing area (11), a receiving unit (13) configured to detect secondary light (15) originating from the processing area (11), and an evaluation unit (17) configured to compare at least one parameter (19) of the secondary light (15) detected by the receiving unit (13) with predefined value ranges (21) of the at least one parameter (19) and, based on this comparison, to determine the presence of the epithelial layer (101) of the eye (100).

Inventors

  • Dan Z. Reinstein
  • Timothy J. Archer
  • Hartmut Vogelsang
  • Radu Cucu
  • Thomas Mohr
  • Wolf Weimer

Assignees

  • CARL ZEISS MEDITEC AG

Dates

Publication Date
20260513
Application Date
20241108

Claims (18)

  1. Device (1) for detecting the presence of an epithelial layer (101) of an eye (100), comprising: - an illumination unit (7) configured to shine illumination light (9) into a processing area (11); - a receiving unit (13) configured to detect secondary light (15) emanating from the processing area (11); - an evaluation unit (17) configured to compare at least one parameter (19) of the secondary light (15) detected by the receiving unit with predefined value ranges (21) of the at least one parameter (19) and, based on this comparison, to determine the presence of the epithelial layer (101) of the eye (100).
  2. Device (1) according Claim 1 , wherein the recording unit (13) is designed to detect the secondary light (15) in a spatially resolved and/or temporally resolved manner and/or synchronized manner with the illumination unit (7) and the evaluation unit (17) is designed to determine the presence of the epithelial layer (101) of the eye (100) in a spatially resolved and/or temporally resolved manner.
  3. Device (1) according Claim 1 or 2 , wherein the evaluation unit (17) compares at least one parameter (19) from the list of parameters (19), comprising: - A spatially resolved reflectance or scattering power of an object arranged in the processing area (11); - A spatially resolved contrast power of an object arranged in the processing area (11); - A spatially resolved transparency of an object arranged in the processing area (11); - A spatially resolved fluorescence power of an object arranged in the processing area (11); with the predefined value ranges (21) of the respective parameter (19).
  4. Device (1) according to one of the Claims 1 until 3 , wherein the evaluation unit (17) is designed is to assume the processing area (11) to be spherical and wherein the lighting unit (7) is designed to provide the illumination light (9) at least section by section substantially perpendicular to such a spherically assumed processing area (11a).
  5. Device (1) according to one of the Claims 1 until 4 , wherein the lighting unit (7) comprises at least one device from the list of devices comprising: - a dome lighting device (65); - a ring lighting device (61); - a side lighting device; and - a slit lighting device.
  6. Device (1) according to one of the Claims 1 until 5 , wherein the lighting unit (7) emits illuminating light (9) with adjustable spectral properties and/or spectral composition; and/or with adjustable temporal properties.
  7. Device (1) according to one of the Claims 1 until 6 , wherein the illumination unit (7) emits illumination light (9) in the blue spectral range and the recording unit (13) has a fluorescence detector configured to detect fluorescence light emitted from the processing area (11).
  8. Device (1) according to one of the Claims 1 until 7 , wherein a distance between the processing area (11) and the lighting unit (7) and/or an azimuthal arrangement, and/or a meridional arrangement of the lighting unit (7) to the processing area (11) and/or a radius (29) of an annular lighting unit (61) is variably adjustable.
  9. Device (1) according to one of the Claims 1 until 8 , further comprising a scanner (35) movably holding the lighting unit (7), wherein the scanner (35) is configured to vary an azimuthal or meridional or azimuthal plus meridional arrangement of the lighting unit (7).
  10. Device (1) according Claim 9 , wherein the evaluation unit (17) is designed to evaluate, depending on an azimuthal and/or meridional position of the illumination unit (7), an azimuthal and/or meridional area of the detected secondary light (15) corresponding to this azimuthal and/or meridional position with respect to at least one parameter (19) of the detected secondary light (15).
  11. A computer-implemented method for detecting the presence of an epithelial layer (101) of an eye (100), comprising: - reading in acquisition data (107a, 107b) representing spatially and/or temporally resolved secondary light (15) originating from the processing area (11); - reading in data from the illumination unit (7) representing at least one illumination parameter of an illumination unit (7); - evaluating at least one parameter (19) from at least one acquisition of the detected secondary light (15) from the acquisition data (107a, 107b); and - comparing the at least one parameter (19) with predefined value ranges (21) of the at least one parameter (19) to determine the presence of the epithelial layer (101) of the eye (100).
  12. Procedure according to Claim 11 , wherein the evaluation further includes the procedural step of detecting at least one abrupt change in brightness (111) in the recording data (107a, 107b)
  13. Procedure according to Claim 11 or 12 , wherein the method further comprises: - reading in azimuthal and/or meridional position information of the illumination unit (7); and - selectively evaluating the image data (107a, 107b) in an image data area which corresponds to an illumination area extracted from the illumination data.
  14. Procedure according to one of the Claims 11 until 13 , wherein the evaluation further includes: the composition of an evaluation result from the sequential determination of the presence of the epithelial layer (101) of the eye (100) in or from different azimuthal and/or meridional image data areas.
  15. Procedure according to one of the Claims 11 until 14 , whereby the evaluation result is determined only for certain regions of interest (ROl: region of interest).
  16. Procedure according to one of the Claims 11 until 15 furthermore, the comparison of a result regarding the presence of the epithelial layer (101) of the eye (100) with epithelial maps determined in advance in a simulation and the identification of a representative of the epithelial maps corresponding to the result.
  17. Procedure according to one of the Claims 11 until 16 , furthermore, including the calculation of the actual epithelial removal achieved based on the determined epithelial map and the necessary simulated removal stored for this purpose; and - Providing the previously calculated result and the corresponding representative of the epithelial maps.
  18. Procedure according to one of the Claims 11 until 17 Furthermore, artificial staining of areas (33) of the result includes either artificially staining areas (33) in which the epithelial layer (101) is present and/or artificially staining areas (33) in which the epithelial layer (101) has been removed and stroma has been detected.

Description

The present invention relates to devices and computer-implemented methods for detecting the presence of an anterior epithelial layer of an eye. There are treatments for a patient's eye that, to improve the outcome or achieve a more precise result, require prior removal of the epithelium or epithelial layer. This is the case, for example, with total resection to achieve a desired stromal ablation or with surface masking of the stroma by the epithelial layer. This is recommended, for instance, in trans-PRK (transepithelial photorefractive keratectomy). In this treatment method, the epithelial layer of the eye is not removed mechanically, but rather by the therapeutic radiation itself. Whenever this disclosure refers to an epithelial layer or the epithelium, it always refers to the anterior corneal epithelium layer. Furthermore, it may be necessary to prepare a patient's eye before or for an ophthalmological procedure. This is particularly important if the ocular surface has irregularities, such as those caused by scars or other abnormalities. A scarred stroma is generally covered by a correspondingly compensating epithelial layer, so significant variations in the thickness of this layer can occur in the area of a scar. The stroma may exhibit depressions ("valleys") and elevations ("peaks"), with the epithelial layer being thicker in the area of a depression than in the area of an elevation. In other words, the thicker epithelial layer can "fill" a depression and thus smooth out irregularities in the stromal surface. Any type of ophthalmological treatment is risky in an eye exhibiting such irregularities, as the epithelial layer and the stroma have different optical properties, whether during ablation with short-pulse lasers (usually emitting in the ultraviolet range) or by creating incisions within the tissue with femtosecond lasers. Further treatments performed within the tissue of the stroma, or more precisely the cornea, such as LIRIC (laser-induced refractive index change) or crosslinking (a [usually] UV irradiation of the eye that increases corneal cross-linking and/or stability), can also be negatively affected by an irregular epithelial layer. In these cases, preparing the eye by restoring a smooth (i.e., free of irregularities) stromal surface is desirable and advantageous before the actual treatment. The preceding explanations merely provide examples where considering the removal of the epithelial layer is advantageous and do not claim to be a complete list of possible applications and uses of the present invention. Both trans-PRK and the aforementioned preparation of the patient's eye benefit from precise knowledge of whether the epithelial layer has already been (completely) removed or is still present (and to what extent). This is particularly relevant when considering which areas of the eye tissue removal has already occurred within the stroma. The present disclosure describes devices and methods which improve or enhance known methods or devices for detecting an epithelial layer. The present invention solves this problem for the aforementioned device for detecting the presence of an epithelial layer of an eye by comprising: - a lighting unit designed to shine illumination light into a processing area; - a recording unit designed to detect secondary light originating from the processing area; and - an evaluation unit designed to compare at least one parameter of the secondary light detected by the recording unit with predefined value ranges of the at least one parameter and, based on this comparison, to determine the presence of the epithelial layer of the eye. Furthermore, the present invention solves this problem for the aforementioned computer-implemented method for detecting the presence of an epithelial layer of an eye by comprising the following method steps: - Reading in recording data that represents spatially and/or temporally resolved secondary light originating from the processing area; - Reading in lighting unit data that represents at least one lighting parameter of a lighting unit; - Evaluating at least one parameter from at least one recording of the detected secondary light from the recording data; and - Comparing at least one parameter with predefined value ranges of at least one parameter to determine the presence of the epithelial layer of the eye. The device and method thus allow for the precise detection of the presence of an epithelial layer. This ensures that, based on two prior thickness measurements of the epithelial layer and subsequent processing (e.g., ablation of the epithelial layer), only the necessary amount of tissue needs to be removed, thus avoiding excessive and unnecessary stromal ablation. Such excessive, unnecessary stromal ablation can currently be selected to ensure that the epithelial layer is completely removed over the entire treated and relevant area, exposing the stroma. According to the invention, it is therefore possible to remove precisely the amoun