Methods and systems for measuring optical parameters

Abstract

A method (400) for verifying an ophthalmic measurement includes obtaining (402) a first measurement of at least one ophthalmic parameter in a first measurement region (202) via an ophthalmic measurement device (102). The first measurement region corresponds to an unaided visible area of ​​a patient's eye (104). Obtaining (406) a second measurement of the at least one ophthalmic parameter in a second measurement region (302) via the measurement device (102). The second measurement region (302) corresponds to an aided visible area of ​​the patient's eye (104). Comparing the first measurement with the second measurement (408). Determining (410) whether the second measurement differs from the first measurement. In response to determining that the second measurement differs from the first measurement, generating (414) an alarm indicating that the second measurement is inaccurate. In response to determining that the second measurement does not differ from the first measurement, accepting (412) that the second measurement is accurate.

Description

Technical Field

[0001] This disclosure generally relates to methods and systems for measuring optical parameters of the eye, and more specifically, but not in a limiting sense, to a method and system for measuring optical parameters that minimizes the effects of distortion caused by manually opening the eyelids. Background Technology

[0002] This section provides background information to help better understand the various aspects of this disclosure. It should be understood that the statements in this section of this document are to be read from this perspective and are not intended as an admission of prior art.

[0003] When performing optical measurements on a patient, it is often important that the patient's eyelids are fully open. Such optical measurements are common, for example, when measuring topography or wavefronts as part of a diagnostic examination to obtain data needed for subsequent surgery, or simply when characterizing the eye as part of a diagnostic examination.

[0004] It is common for patients' eyelids not to open sufficiently, making it impossible to collect data in the desired area. This is usually due to factors such as the patient's age or injury to the eye or surrounding area. In these cases, the device operator often manually assists the patient in opening their eyelids. Sometimes, depending on the level of challenge and the ease of accessing the eye, a second operator may provide assistance.

[0005] When manually opening the eyelids, the eyeball may be unintentionally distorted. This can lead to inaccurate subsequent measurements. For example, measurements of astigmatism or higher-order aberrations may be particularly affected. Inaccurate measurements can negatively impact any surgical procedure, including, for example, intraocular lens implantation or corneal refractive surgery. Operators receive optimal technical training to minimize potential distortions. However, variability exists among operators, and even for the most experienced, manually manipulating the eyelids can be challenging, especially with particularly challenging patients. Furthermore, when a patient's eyelids are opened manually or mechanically, the tear film associated with the patient's cornea often dries out because the patient cannot blink. This drying of the tear film also contributes to inaccurate ophthalmic measurements. Summary of the Invention

[0006] Various aspects of this disclosure relate to a method for verifying ophthalmic measurements. The method includes obtaining a first measurement of at least one ophthalmic parameter in a first measurement region via an ophthalmic measuring device. The first measurement region corresponds to an unaided visible area of ​​a patient's eye. A second measurement of the at least one ophthalmic parameter in a second measurement region via the measuring device. The second measurement region corresponds to an aided visible area of ​​the patient's eye. The first measurement is compared with the second measurement. It is determined whether the second measurement differs from the first measurement. In response to determining that the second measurement differs from the first measurement, an alarm is generated indicating that the second measurement is inaccurate. In response to determining that the second measurement does not differ from the first measurement, the second measurement is accepted as accurate. A first reflectance associated with the first measurement and a second reflectance associated with the second measurement are obtained using the ophthalmic measuring device. These first reflectances are compared with these second reflectances. A difference is then determined between these first reflectances and these second reflectances. In response to determining that a difference exists between these second reflectances and these first reflectances, an alarm is generated indicating that the patient's tear film has dried. In response to determining that no difference exists between these second reflectances and these first reflectances, the second measurement is accepted as accurate.

[0007] Various aspects of this disclosure relate to a computer program product comprising a non-transitory computer-usable medium containing computer-readable program code. The computer-readable program code is adapted to be executed to implement a method comprising: receiving from an ophthalmic measuring device a first measurement of at least one ophthalmic parameter in a first measuring region. The first measuring region corresponds to an unaided visible region of a patient's eye. Receiving from the measuring device a second measurement of the at least one ophthalmic parameter in a second measuring region. The second measuring region corresponds to an aided visible region of the patient's eye. Comparing the first measurement with the second measurement. Determining whether the second measurement differs from the first measurement. Generating an alarm indicating that the second measurement is inaccurate in response to determining that the second measurement differs from the first measurement. Accepting the second measurement as accurate in response to determining that the second measurement is not different from the first measurement. Receiving from the ophthalmic measuring device a first reflection associated with the first measurement and a second reflection associated with the second measurement. Determining whether there is a difference between these first reflections and these second reflections. Generating an alarm indicating that the patient's tear film has dried out in response to determining that there is a difference between these second reflections and these first reflections. In response to the determination that there is no difference between these second reflections and these first reflections, the second measurement is accepted as accurate.

[0008] Various aspects of this disclosure relate to a system for ophthalmic measurements. The system includes an ophthalmic measuring device. A processor is coupled to the ophthalmic measuring device. The processor is configured to receive from the ophthalmic measuring device a first measurement of at least one ophthalmic parameter in a first measuring region. The first measuring region corresponds to the unaided visible region of a patient's eye. A second measurement of the at least one ophthalmic parameter is received from the ophthalmic measuring device in a second measuring region. The second measuring region corresponds to the aided visible region of the patient's eye. The first measurement is compared with the second measurement, and it is determined whether the second measurement differs from the first measurement. In response to determining that the second measurement differs from the first measurement, an alarm is generated indicating that the second measurement is inaccurate. In response to determining that the second measurement is indistinguishable from the first measurement, the second measurement is accepted as accurate. The processor is configured to receive from the ophthalmic measuring device a first reflection associated with the first measurement and a second reflection associated with the second measurement. A difference is determined between these first reflections and these second reflections. In response to determining that a difference exists between these second reflections and these first reflections, an alarm is generated indicating that the patient's tear film has dried out. In response to the determination that there is no difference between these second reflections and these first reflections, the second measurement is accepted as accurate.

[0009] This summary is provided to introduce a selection of concepts further described in the following detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to serve as an aid in limiting the scope of the claimed subject matter. Attached Figure Description

[0010] The contents of this disclosure can be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be emphasized that, in accordance with industry standard practice, the various features are not drawn to scale. In fact, the dimensions of the various features can be arbitrarily increased or decreased for clarity of discussion.

[0011] Figure 1 This is a block diagram of an ophthalmic measurement system based on aspects of this disclosure;

[0012] Figure 2 This is a frontal view of the eye, without assistance in opening the eyelids and showing the first measurement area;

[0013] Figure 3 It is a frontal view of the eye, which helps to open the eyelids and shows the second measurement area;

[0014] Figure 4 This is a flowchart of a method for verifying optical measurements according to aspects of this disclosure; and

[0015] Figures 5A to 5D It is a simplified diagram of corneal topography, showing the changes in ophthalmic measurements during different eyelid opening states. Detailed Implementation

[0016] Various embodiments will now be described more fully with reference to the accompanying drawings. However, this disclosure can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein.

[0017] Before any medical intervention to the eye, such as refractive surgery, retinal surgery, or lens replacement surgery, many ophthalmic parameters are commonly used, such as corneal curvature (also known as corneal curvature), axial length, aberration measurements, anterior corneal surface measurements (also known as corneal topography), or full thickness measurements of the corneal structures to be measured (also known as corneal tomography). These ophthalmic parameters are typically measured using specialized equipment and require that a minimum surface area of ​​the anterior portion of the eye be visible. In the specific case of lens replacement surgery, the measurement of these ophthalmic parameters determines the optical properties of the replacement lens. Therefore, inaccurate measurements of these ophthalmic parameters can adversely affect the efficacy of any such medical intervention on the eye.

[0018] Figure 1 This is a block diagram of an ophthalmic measurement system 100. The measurement system 100 includes a measurement device 102 positioned to visualize a patient's eye 104. In various embodiments, the measurement device can be any ophthalmic measurement device, such as a keratometer, ultrasound biometer, wavefront device, topography device, aberration measurement device, ophthalmic optical coherence tomography (OCT) device, or any other ophthalmic measurement device. The measurement device 102 includes a processor 106 configured to store and compare ophthalmic parameters obtained by the measurement device 102. In various embodiments, the processor 106 can be integrated with the measurement device 102; however, in other embodiments, the processor 106 can be a separate device coupled to the measurement device 102 via, for example, wired or wireless coupling. The processor 106 can be any microprocessor, microcontroller, programmable element, or other device or set of devices that processes instructions for controlling the measurement device 102.

[0019] In some embodiments, data bus 109 (a serial bus in the illustrated embodiment) couples various components of measurement device 102 together, enabling data communication between them. In typical embodiments, data bus 109 may include, for example, hardware, software embedded in a computer-readable medium, or any combination of coded logic (e.g., firmware) incorporated in hardware or otherwise stored to couple components of measurement device 102 to each other. By way of example, and not limitation, data bus 109 may include an Accelerated Graphics Port (AGP) or other graphics bus, a Controller Area Network (CAN) bus, a Front Side Bus (FSB), HyperTransport (HT) Interconnect, Infinite Bandwidth Interconnect, Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or any other suitable bus, or a combination of two or more of these. In various embodiments, data bus 109 may include any number, type, or configuration of data buses 109 where appropriate.

[0020] Figure 2 This is a front view of eye 104, with eyelid 206 unassisted and showing the first measurement region 202. In a typical embodiment, the first measurement region 202 may be, for example, a small diameter surrounding the pupil 204 or a small diameter surrounding some other reference (e.g., visual axis or line of sight). Visualization of the first measurement region 202 is typically possible without any manual manipulation of the eyelid 206.

[0021] Figure 3 This is a front view of eye 104, with eyelid 206 assisted in opening and showing a second measurement region 302. The second measurement region 302 is larger than and includes the first measurement region 202. Specifically, the second measurement region 302 includes a sub-region 304 that overlaps with the first measurement region 202. Furthermore, the second measurement region 302 includes areas of the eye that would be obscured during unassisted eyelid opening 206. If the patient is able to open the eyelid completely without assistance, aberrations such as defocus, astigmatism, or higher-order aberrations on the sub-region 304 portion of the second measurement region 302 will be similar to ophthalmic parameters measured only on the first measurement region 202. Therefore, any difference between the ophthalmic parameters measured on the second measurement region 302 and those measured on the first measurement region 202 may indicate unintentional deformation of the eyeball, including, for example, deformation caused by manual eyelid opening 206.

[0022] It should be noted that, Figures 2 to 3The first measurement area 202 and the second measurement area 302 shown are merely exemplary. During operation, the position, size, and shape of the first measurement area 202 and the second measurement area 302 will vary depending on the ophthalmic parameter being measured. For example, in Figures 2 to 3 In this example, the first measurement region 202 and the second measurement region 302 are shown centered on the pupil 204. In various embodiments, the first measurement region 202 and the second measurement region 302 may be offset from the pupil 204 or may be located at other locations on the eye 104 to include the sclera, iris, or other areas of the eye 104.

[0023] Common Reference Figures 1 to 3 During operation, a first measurement of one or more ophthalmic parameters is performed on a first measurement area 202 and transmitted to processor 106. The ophthalmic parameter is measured on the first measurement area 202 without providing the patient with assistance in opening the eyelids 206. Assistance is then provided to help the patient open the eyelids 206 to a greater extent otherwise possible without assistance. A second measurement of the same ophthalmic parameter is performed on a second measurement area 302 and transmitted to processor 106. Processor 106 compares the second measurement with the first measurement. In various embodiments, processor 106 may magnify the range of the ophthalmic parameter measured on the first measurement area 202 to match the range of the second measurement area 302. This practice is commonly referred to as “data scaling” or “feature scaling.” In other embodiments, processor 106 may sample the ophthalmic parameter measured on a sub-region 304 of the second measurement area 302 and compare the ophthalmic parameter of the sub-region 304 with the ophthalmic parameter measured only on the first measurement area 202. This practice is commonly referred to as “data sampling.” In various embodiments, processor 106 compares the second measurement with the first measurement to assess the consistency of the shape of eye 104. In various embodiments, this comparison can be performed, for example, by root mean square analysis of ophthalmic parameters. In various embodiments, processor 106 may utilize registration data to determine where ophthalmic parameters are measured in eye 104. This registration data helps determine a common reference between the first measurement region 202 and the second measurement region 302.

[0024] Still referencing Figures 1 to 3If the processor 106 detects no difference between the ophthalmic parameters measured in the first measurement area 202 and the ophthalmic parameters measured in the second measurement area 302, no action is taken and the processor 106 determines that the ophthalmic parameters measured in the second measurement area 302 are accurate. If the processor 106 detects a difference between the ophthalmic parameters measured in the first measurement area 202 and the ophthalmic parameters measured in the second measurement area 302, the processor 106 generates an alarm to notify the operator that the eyeball of the eye 104 may be deformed, causing the ophthalmic parameters measured in the second measurement area 302 to be inaccurate. In various embodiments, the alarm may be, for example, a visual indication, a text indication, or an auditory indication. The alarm prompts the clinician to check the aids provided to the patient's eyelid 206 and remeasure the ophthalmic parameters in the second measurement area 302.

[0025] Still referencing Figures 1 to 3 During operation, in various embodiments, ophthalmic parameters may include reflections received from a first measurement area 202 and a second measurement area 302. The processor 106 compares the reflections detected from the first measurement area 202 with the reflections detected from the second measurement area 302. Specifically, the processor determines whether blurring or other changes in reflection have occurred between a first measurement performed on the first measurement area 202 and a second measurement performed on the second measurement area 302. Such changes in reflection between the first and second measurements may indicate that the patient's tear film is dry. In response to this determination, the patient's eye should be flushed or otherwise moistened to replenish the tear film to ensure accurate measurement of the ophthalmic parameters. Furthermore, the processor determines whether there is no reflection between the first measurement performed on the first measurement area 202 and the second measurement performed on the second measurement area 302. The absence of reflection indicates that the signal from the measuring device 102 is obstructed or otherwise interfered with. In various embodiments, this signal may be, for example, visible light emitted from a light-emitting diode (LED). In other embodiments, this signal may be, for example, laser light emitted from an optical coherence tomography (OCT) device or a wavefront device. The absence of such a reflection may indicate, for example, the need to reposition the device that assists in opening the patient's eyelids.

[0026] Figure 4This is a flowchart of a method 400 for validating ophthalmic measurements. Method 400 begins at step 401. At step 402, ophthalmic parameters are measured in a first measurement region 202, and the measured ophthalmic parameters are transmitted to a processor 106. During step 402, the patient's eyelids 206 are not assisted in being opened. At step 404, assistance is provided to open the patient's eyelids 206 to a degree sufficient to expose a second measurement region 302. At step 406, ophthalmic parameters are measured in the second measurement region 302, and the measured ophthalmic parameters are transmitted to the processor 106. At step 408, the processor 106 compares the ophthalmic parameters measured in the first measurement region 202 with ophthalmic parameters measured in at least one of the second measurement region 302 or a sub-region 304 of the second measurement region 302. In step 408, in various embodiments, the comparison may utilize data scaling such that the ophthalmic parameters measured in the first measurement region 202 are magnified and compared with the ophthalmic parameters measured in the second measurement region 302. In other embodiments, the comparison may utilize data sampling such that a sub-region 304 is sampled from the ophthalmic parameters measured in the second measurement region 302 and compared with the ophthalmic parameters measured in the first measurement region 202.

[0027] Still referencing Figure 4 In step 410, it is determined whether the ophthalmic parameters measured in the first measurement region 202 differ from those measured in the sub-region 304 of the second measurement region 302. If it is determined in step 410 that there is no difference between the ophthalmic parameters measured in the first measurement region 202 and those measured in the sub-region 304 of the second measurement region 302, then method 400 proceeds to step 412. In step 412, processor 106 accepts that the ophthalmic parameters measured in the second measurement region 302 are accurate. From step 412, method 400 ends in step 413. In various embodiments, method 400 may be repeated, for example, to measure different ophthalmic parameters or different anatomical regions of the eye 104.

[0028] Still referencing Figure 4 If, in step 410, it is determined that the ophthalmic parameters measured in the first measurement region 202 differ from those measured in a sub-region 304 of the second measurement region 302, then method 400 proceeds to step 414. In step 414, processor 106 generates an alarm indicating that the ophthalmic parameters measured in the second measurement region 302 may be inaccurate due to eye deformation, for example, caused by an aid provided to the patient's eyelid 206. In step 414, the alarm may be, for example, a visual indication, a text indication, or an auditory indication. In step 416, the clinician adjusts the aid provided to the patient's eyelid 206. From step 416, method 400 returns to step 406 to remeasure the ophthalmic parameters in the second measurement region 302.

[0029] Figures 5A to 5D This is a simplified diagram of corneal topography, showing the changes in ophthalmic measurements during different eyelid opening states at 206. Figure 5A and Figure 5B This shows a natural corneal topography with eyelid 206 partially closed. Boxes 502(a)-(d) show smaller areas of coverage. Figure 5C A topographical map is shown, in which eyelid 206 is wide open, for example, when eyelid 206 is opened to provide assistance to a patient. Eye 104 remains in a natural state because... Figure 5C Box 502(c) in the middle displays something similar to Figure 5A Measurement of box 502(a) in the figure. Figure 5D Showing relative to Figure 5B The corneal topography within box 502(b) has been altered, indicating that eye 104 is not in its natural state and that there may be deformation of the eyeball of eye 104.

[0030] Figure 5A and Figure 5C This illustrates a comparison when eyelid 206 remains wide open and eye 104 remains in a natural state. The corneal topography region in the natural state is indicated by box 502(a). The corneal topography in the natural state is similar to the state where the eye is open, as shown... Figure 5A Box 502(a) and Figure 5C The similarity between boxes 502(c) is shown. Figure 5B and Figure 5D The corneal topography is shown to differ from the natural state when the eyelid 206 is kept open, as illustrated by the difference between boxes 502(b) and 502(d). The eye 104 does not remain in its natural state and there may be deformation of the eyeball of the eye 104.

[0031] Depending on the implementation, certain actions, events, or functions of any algorithm described herein may be performed in a different order, and may be added, combined, or omitted entirely (e.g., not all described actions or events are necessary for algorithmic practice). Furthermore, in some embodiments, actions or events may be performed concurrently, for example, through multithreading, interrupt handling, or multiple processors or processor cores, or on other parallel architectures, rather than sequentially. Although some computer-implemented tasks are described as being performed by a specific entity, other embodiments in which these tasks are performed by different entities are also possible.

[0032] For the purposes of this application, the term "computer-readable storage medium" includes one or more tangible computer-readable storage media having a structure. By way of example, and not limitation, a computer-readable storage medium may, where appropriate, include semiconductor-based or other integrated circuits (ICs) (e.g., field-programmable gate arrays (FPGAs) or application-specific ICs (ASICs)), hard disks, HDDs, hybrid hard disks (HHDs), optical disks, optical disk drives (ODDs), magneto-optical disks, magneto-optical drives, floppy disks, floppy disk drives (FDDs), magnetic tape, holographic storage media, solid-state drives (SSDs), RAM drives, secure digital cards, secure digital drives, flash memory cards, flash memory drives, or any other suitable tangible computer-readable storage media, or a combination of two or more of these.

[0033] As will be understood by those skilled in the art, the term “substantially” is defined as meaning to a great extent, but not necessarily all, of the specified content (and includes the specified content; for example, substantially 90 degrees includes 90 degrees, and substantially parallel includes parallel). In any disclosed embodiment, the terms “substantially,” “about,” “roughly,” and “approximately” may be replaced by “[percentage]” of the specified content.

[0034] The conditional language used herein, particularly words such as “may,” “possibly,” “can,” and “for example,” unless explicitly stated otherwise or otherwise understood in the context in which they are used, is generally intended to convey that certain embodiments include certain features, elements, and / or states, while other embodiments do not. Therefore, this conditional language is not intended in general to imply that features, elements, and / or states are required by any means in one or more embodiments, or that one or more embodiments necessarily include logic for determining, with or without author input or prompting, whether such features, elements, and / or states are included in any particular embodiment or will be implemented in that embodiment.

[0035] While the detailed description above has shown, described, and pointed out novel features applicable to various embodiments, it should be understood that various omissions, substitutions, and changes can be made to the form and details of the illustrated apparatus without departing from the spirit of this disclosure. As will be appreciated, the methods described herein can be implemented in forms that do not provide all the features and benefits set forth herein, as some features may be used or practiced separately from other features. The scope of protection is defined by the appended claims, not by the foregoing description. All variations within the equivalent meaning and scope of the claims should be included within their scope.

Claims

1. A method of verifying an ophthalmic measurement, the method comprising: obtaining, via an ophthalmic measurement device, a first measurement of at least one ophthalmic parameter over a first measurement area, the first measurement area corresponding to an unassisted measurable area of a patient's eye, the first measurement area covering less than an entire cornea of a user's eye; obtaining, via the ophthalmic measurement device, a second measurement of the at least one ophthalmic parameter over a second measurement area, the second measurement area corresponding to an assisted measurable area of the patient's eye, wherein the second measurement area includes a sub-area that coincides with the first measurement area, the second measurement area covering the entire cornea; obtaining, from the ophthalmic measurement device, a first reflection associated with the first measurement and a second reflection associated with the second measurement; sampling a portion of the second measurement corresponding to the sub-area; comparing the sampled portion of the second measurement to the first measurement, including scaling the first measurement area to the second measurement area; determining whether the second measurement differs from the first measurement, the second measurement differing from the first measurement including a difference in the at least one ophthalmic parameter between the first and second measurements of the at least one ophthalmic parameter; in response to determining that the second measurement differs from the first measurement, generating an alert that the second measurement is inaccurate; comparing the first reflection to the second reflection; determining whether there is a difference between the first and second reflections; and in response to determining that there is a difference between the second and first reflections, generating an alert that the patient's tear film has dried.

2. The method of claim 1, wherein, the ophthalmic parameter is at least one of a corneal curvature, an axial length, an aberrometry measurement, and a corneal topography.

3. The method of claim 1, wherein, the ophthalmic measurement device is at least one of a corneal curvature meter, an ultrasonic biometer, a wavefront device, a topographer, and an aberrometry device.

4. The method of claim 1, wherein, the alert is at least one of a visual alert, a text alert, and an audible indication.

5. The method of claim 1, comprising: in response to determining that the second measurement differs from the first measurement, rejecting the second measurement; and repeating the second measurement.

6. The method of claim 5, comprising comparing the repeated second measurement to the first measurement. the comparison includes determining a common reference between the first measurement area and the second measurement area.

7. The method of claim 1, wherein, 8. A computer program product, the computer program product comprising a non-transitory computer usable medium having a computer readable program code embodied therein, the computer readable program code adapted to be executed to implement a method, the method comprising: receiving, from an ophthalmic measurement device, a first measurement of at least one ophthalmic parameter over a first measurement area, the first measurement area corresponding to an unassisted measurable area of a patient's eye, the first measurement area covering less than an entire cornea of a user's eye; ​ receive, from the ophthalmic measurement device, a second measurement of the at least one ophthalmic parameter on a second measurement area, the second measurement area corresponding to an assisted measurable area of the patient's eye, wherein the second measurement area includes a sub-area that overlaps the first measurement area, the second measurement area covering the entire cornea; sample a portion of the second measurement corresponding to the sub-area; compare the sampled portion of the second measurement to the first measurement, including scaling the first measurement area to the second measurement area; receive, from the ophthalmic measurement device, a first reflection associated with the first measurement and a second reflection associated with the second measurement; determine whether the second measurement is different from the first measurement, the second measurement being different from the first measurement including a difference in the at least one ophthalmic parameter between the first and second measurements of the at least one ophthalmic parameter; generate an alert that the second measurement is inaccurate in response to determining that the second measurement is different from the first measurement; determine whether there is a difference between the first and second reflections; generate an alert that the patient's tear film has dried in response to determining that there is a difference between the second and first reflections; and accept the second measurement as accurate in response to determining that there is not a difference between the second and first reflections.

9. The computer program product of claim 8, wherein: the ophthalmic parameter is at least one of a corneal curvature, an axial length, an aberrometry measurement, and a corneal topography; the ophthalmic measurement device is at least one of a corneal curvature meter, an ultrasonic biomicroscope, a wavefront device, a topographer, and an aberrometry device.

10. The computer program product of claim 8, wherein, the alert is at least one of a visual alert, a text alert, and an audible indication.

11. The computer program product of claim 8, comprising: reject the second measurement in response to determining that the second measurement is different from the first measurement; repeat the second measurement; and compare the repeated second measurement to the first measurement.

12. The computer program product of claim 8, wherein, the comparison includes determining a common reference between the first measurement area and the second measurement area.

13. A system for ophthalmic measurements, the system comprising: an ophthalmic measurement device; a processor coupled to the ophthalmic measurement device, the processor configured to: receive, from the ophthalmic measurement device, a first measurement of at least one ophthalmic parameter on a first measurement area, the first measurement area corresponding to an unassisted measurable area of a patient's eye, the first measurement area covering less than the entire cornea of the user's eye; receive, from the ophthalmic measurement device, a second measurement of the at least one ophthalmic parameter on a second measurement area, the second measurement area corresponding to an assisted measurable area of the patient's eye, wherein the second measurement area includes a sub-area that overlaps the first measurement area, the second measurement area covering the entire cornea; sample a portion of the second measurement corresponding to the sub-area; comparing the sampled portion of the second measurement to the first measurement, including scaling the first measurement area to the second measurement area; receiving, from the ophthalmic measurement device, a first reflection associated with the first measurement and a second reflection associated with the second measurement; determining whether the second measurement is different from the first measurement, the second measurement being different from the first measurement including a difference in the at least one ophthalmic parameter between the first and second measurements of the at least one ophthalmic parameter; in response to determining that the second measurement is different from the first measurement, generating an alert that the second measurement is inaccurate; and determining whether there is a difference between the first reflection and the second reflection; in response to determining that there is a difference between the second reflection and the first reflection, generating an alert that the patient’s tear film has dried; and in response to determining that there is not a difference between the second reflection and the first reflection, accepting the second measurement as accurate.

14. The system of claim 13, wherein: the ophthalmic parameter is at least one of a corneal curvature, an axial length, an aberrometry measurement, and a corneal topography; and the ophthalmic measurement device is at least one of a corneal curvature meter, an ultrasonic biomicroscope, a wavefront device, a topographer, and an aberrometry device.

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