Ophthalmic Instruments Research Articles

Guideline Implementation: Surgical Instrument Cleaning

Cleaning, decontaminating, and handling instructions for instruments vary widely based on the type of instrument and the manufacturer. Processing instruments in accordance with the manufacturer’s instructions can help prevent damage and keep devices in good working order. Most importantly, proper cleaning and disinfection may prevent transmission of pathogenic organisms from a contaminated device to a patient or health care worker. The updated AORN “Guideline for cleaning and care of surgical instruments” provides guidance on cleaning, decontaminating, transporting, inspecting, and storing instruments. This article focuses on key points of the guideline to help perioperative personnel implement appropriate instrument care protocols in their practice settings. The key points address timely cleaning and decontamination of instruments after use; appropriate heating, ventilation, and air conditioning parameters for the decontamination area; processing of ophthalmic instruments and laryngoscopes; and precautions to take with instruments used in cases of suspected prion disease. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.

Wideband Electrically-Pumped 1050 nm MEMS-Tunable VCSEL for Ophthalmic Imaging.

In this paper, we present a 1050 nm electrically-pumped micro-electro-mechanically-tunable vertical-cavity-surface-emitting-laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost & complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over 6 mm × 6 mm & 3 mm × 3 mm fields to show retinal vasculature and capillary structure near the fovea. These results demonstrate the feasibility of electrically pumped MEMS-VCSELs in ophthalmic instrumentation, the largest clinical application of OCT. In addition, we estimate that the 3 dB coherence length in air is 225 meters ± 51 meters, far greater than required for ophthalmic SS-OCT and suggestive of other distance ranging applications.

Wide-field optical model of the human eye with asymmetrically tilted and decentered lens that reproduces measured ocular aberrations

Eye models are valuable tools that can help delineate the role of anatomical parameters on visual performance and guide the design of advanced ophthalmic instrumentation. We propose an optically accurate wide-field schematic eye that reproduces the complete aberration profile of the human eye across a wide visual field. The optical performance of the schematic eye is based on experimentally measured wavefront aberrations taken with a four mm pupil for the central 80° of the horizontal meridian (101 eyes) and 50° of the vertical meridian (10 eyes). Across the entire field of view, our model shows excellent agreement with the measured data both comprehensively and for low-order and high-order aberrations. In comparison to previous eye models, our schematic eye excels at reproducing the aberrations of the retinal periphery. Also unlike previous models, tilt and decentering of the gradient refractive index crystalline lens, which arose naturally through the optimization process, permits our model to mimic the asymmetries of real human eyes while remaining both anatomically and optically correct. Finally, we outline a robust reverse building eye modeling technique that is capable of predicting trends beyond those defined explicitly in the optimization routine. Our proposed model may aid in the design of wide-field imaging instrumentation, including optical coherence tomography, scanning laser ophthalmoscopy, fluorescence imaging, and fundus photography, and it has the potential to provide further insights in the study and understanding of the peripheral optics of the human eye.

Graft biomechanics following three corneal transplantation techniques

Purpose:To compare corneal biomechanical properties following three different transplantation techniques, including Descemet stripping automated endothelial keratoplasty (DSAEK), deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) in comparison to normal eyes.Methods:This cross-sectional comparative study included 118 eyes: 17 eyes of 17 patients received DSAEK, 23 eyes of 21 patients underwent DALK using Anwar's big bubble technique, and 45 eyes of 36 patients had PK; 33 right eyes of 33 normal subjects served as the control group. Using the ocular response analyzer (ORA, Reichert Ophthalmic Instruments, Buffalo, New York, USA), corneal hysteresis (CH) and corneal resistance factor (CRF) were measured and compared among the study groups at least 3 months after all sutures were removed.Results:Mean patient age was 26.9 ± 5.0 years in the control group, 28.8 ± 4.2 in the PK group, 27.2 ± 6.5 in the DALK group, and 62.5 ± 16.8 in the DSAEK group (P < 0.001). Central corneal thickness (CCT) was 539.0 ± 24.8, 567.5 ± 38.8, 547.0 ± 42.6 and 631.1 ± 84.8 μm, respectively (P < 0.001). CH and CRF were significantly lower in the DSAEK group (7.79 ± 2.0 and 7.88 ± 1.74 mmHg, respectively) as compared to the PK (10.23 ± 2.07 and 10.13 ± 2.22 mmHg, respectively) and DALK (9.64 ± 2.07 and 9.36 ± 2.09 mmHg, respectively) groups. The two latter groups demonstrated biomechanical parameters comparable to normal subjects (9.84 ± 1.59 and 9.89 ± 1.73 mmHg, respectively).Conclusion:Graft biomechanical parameters after DSAEK are lower than those following PK and DALK. After PK and DALK in keratoconic eyes, these metrics are increased to normal values. These differences may have implications for interpreting intraocular pressure or planning graft refractive surgery after keratoplasty.

Factors Influencing Efficacy of Peripheral Corneal Relaxing Incisions during Cataract Surgery.

Purpose. To evaluate influencing factors on the residual astigmatism after performing peripheral corneal relaxing incisions (PCRIs) during cataract surgery. Methods. This prospective study included patients who were scheduled for cataract surgery with PCRIs. Optical biometry (IOLMaster 500, Carl Zeiss Meditec AG, Germany) was taken preoperatively, 1 week, 4 months, and 1 year postoperatively. Additionally, corneal topography (Atlas model 9000, Carl Zeiss Meditec AG, Germany), ORA (Ocular Response Analyzer, Reichert Ophthalmic Instruments, USA), and autorefraction (Autorefractometer RM 8800 Topcon) were performed postoperatively. Results. Mean age of the study population (n = 74) was 73.5 years (±9.3; range: 53 to 90) and mean corneal astigmatism preoperatively was −1.82 D (±0.59; 1.00 to 4.50). Mean corneal astigmatism was reduced to 1.14 D (±0.67; 0.11 to 3.89) 4 months postoperatively. A partial least squares regression showed that a high eccentricity of the cornea, a large deviation between keratometry and topography, and a high preoperative astigmatism resulted in a larger postoperative error concerning astigmatism. Conclusions. PCRI causes a reduction of preoperative astigmatism, though the prediction is difficult but several factors were found to be a relevant source of error.

Does Corneal Hysteresis Correlate with Endothelial Cell Density?

BackgroundOur aim was to determine if there is a correlation between corneal biomechanical properties, endothelial cell count, and corneal pachymetry in healthy corneas.Material/MethodsNinety-two eyes of all subjects underwent complete ocular examination, including intraocular pressure measurement by Goldmann applanation tonometer, objective refraction, and slit-lamp biomicroscopy. Topographic measurements and corneal pachymetry were performed using a Scheimpflug-based (Pentacam, Oculus, Germany) corneal topographer. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured with an Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments, Buffalo, NY). Endothelial cell count measurement was done using a specular microscope (CellChek, Konan, USA).ResultsRight eye values of the subjects were taken for the study. The mean CH was 11.5±1.7 mmHg and the mean CRF was 11.2±1.4 mmHg. Mean intraocular pressure was 15.3±2.3 mmHg. The mean endothelial cell count was 2754±205 cells/mm2. No correlation was found between biomechanical properties of cornea and endothelial cell count. There was a significant positive correlation between CH, CRF, and corneal thickness (p<0.001; r=0.79).ConclusionsThe corneal biomechanical properties significantly correlated with corneal thickness. We found no correlation between CH and CRF with the endothelial cell density in normal subjects.

Effect evaluation of three different cleaning methods on microsurgical instruments cleaning

Objective To discuss the best way of microsurgical instruments cleaning to improve the cleaning effect .Methods Based on random principle , the ophthalmic and hand surgery microsurgery instruments were divided into three groups （ control group ,soak group and oscillation of washing group ,each group 450 cases）after being used.The general group was cleaned directly without primary treatment ,soak group used multienzyme abluent and oscillation of washing group used ultrasonic cleaning respectively .Then all the three groups were cleaned by gentle cycle of automated Multi-chamber Washer .The cleaning effects were checked and compared by single eyeballing and magnification inspected .Results It was found that qualification numbers of the three groups by single eyeballing was 341,402 and 439, with qualification rates 75.78%,89.33% and 97.56%respectively .and qualification numbers by magnification inspected was 319, 381 and 428, and that qualification rates were 70.89%,84.67%and 95.11%, respectively.The qualified rates of oscillation of washing group were higher than that of other two groups , the differences were statistically significant （χ^2 =99.894 6, 96.682 3, respectively;P〈0.01）.Conclusions The ideal method of microsurgical instruments cleaning is use the automated Multi-chamber Washer after soaking in multienzyme abluent and using Ultrasonic cleaning . Key words: Microsurgical instruments; Cleaning; Primary treatment; Effect evaluation

Extraction of ultra-high frequency retinal motions with a line scanning quasi-confocal ophthalmoscope

Ultra-high frequency motions of the retina severely affect the stabilization of images and result in significant imaging distortions. In this paper, a high speed line scanning quasi-confocal ophthalmoscope (LSO) capable of 160 frames per second was devised for generating stable undistorted retinal images. This technique resulted in minimal intra-frame motions, and a strip-based cross correlation algorithm with sub-pixel resolution was applied to extract retinal motions. Three retinal motion components at rates of up to 1600 Hz were clearly distinguished and extracted accurately for the first time using ophthalmic imaging methods. This was especially apparent for the fastest tremor and microsaccade movements that cannot be estimated from previously reported ophthalmic imaging instruments. Furthermore, these results were consistent with retinal motion characteristics obtained with optical lever methods, validating this technique. Actually, the LSO system has great potential to extract retinal motions, and some other tracking systems may be adopted to correct retinal motions in ophthalmic imaging modalities.

Central corneal thickness measurement by Fourier domain optical coherence tomography, ocular response analyzer and ultrasound pachymetry

PurposeTo assess the repeatability, reproducibility, and agreement of central corneal thickness (CCT) measured by non-contact Fourier domain optical coherence tomography (FD-OCT; OptoVue) with the other two contact devices, ocular response analyzer (ORA; Reichert Ophthalmic Instruments) and Ultrasound Pachymetry (USP; DGH Technologies). MethodsThis observational cross-sectional study measured CCT sequentially using FD-OCT, ORA and USP. The first 16 volunteers (32 eyes) received three measurements by two independent examiners in a single session to determine intra-observer repeatability and inter-observer reproducibility. An additional 27 volunteers (54 eyes) received one measurement by the same examiner. The measurements of all 86 eyes were analyzed for the difference, correlation, and agreement among the three devices. ResultsFD-OCT measured the thinnest while USP measured the thickest CCT (548.6 ± 28.3 μm, 556.9 ± 28.8 μm, and 560.0 ± 28.8 μm by FD-OCT, ORA, and USP, respectively, p < 0.001). The mean differences (lower/upper limit of agreement) for CCT measurements were 8.4 ± 7.6 μm (−6.5/23.2) between ORA and FD-OCT, 11.4 ± 7.3 μm (−2.8/25.7) between USP and FD-OCT, and 3.1 ± 5.1 μm (−6.9/13.1) between ORA and USP. The intra-class correlation coefficients were above 0.98 for all tested groups. FD-OCT had the lowest intra-examiner variability (coefficient of repeatability of 0.64%) and lowest inter-examiner variability (coefficient of reproducibility of 1.16%). ConclusionFD-OCT, ORA, and USP demonstrated good inter-observer reproducibility and intra-observer repeatability. The three measurements were highly correlated; however, systematic differences between the three tested devices did exist. FD-OCT was a reliable and examiner-independent method in CCT measurement.

A Multi-Function Force Sensing Instrument for Variable Admittance Robot Control in Retinal Microsurgery.

Robotic systems have the potential to assist vitreoretinal surgeons in extremely difficult surgical tasks inside the human eye. In addition to reducing hand tremor and improving tool positioning, a robotic assistant can provide assistive motion guidance using virtual fixtures, and incorporate real-time feedback from intraocular force sensing ophthalmic instruments to present tissue manipulation forces, that are otherwise physically imperceptible to the surgeon. This paper presents the design of an FBG-based, multi-function instrument that is capable of measuring mN-level forces at the instrument tip located inside the eye, and also the sclera contact location on the instrument shaft and the corresponding contact force. The given information is used to augment cooperatively controlled robot behavior with variable admittance control. This effectively creates an adaptive remote center-of-motion (RCM) constraint to minimize eye motion, but also allows the translation of the RCM location if the instrument is not near the retina. In addition, it provides force scaling for sclera force feedback. The calibration and validation of the multi-function force sensing instrument are presented, along with demonstration and performance assessment of the variable admittance robot control on an eye phantom.

Towards patient self‐triage in the ophthalmic emergency department: sensitivity and specificity of a self‐triage instrument

Trained ophthalmic triage staff may not constantly be available in the emergency department of a specialized ophthalmic hospital, particularly at night. To support the current triage process, the aim of this study was to develop an ophthalmic instrument of patient self-triage (ISET). A preliminary ISET, in the form of a pen-and-paper questionnaire, was refined and validated in a two-step procedure. In a first explorative step, we compared the results of the ISET with the results of the regular triage process during the day, that is, triage by a trained triage assistant in a specialized ophthalmic hospital. As several patients needed guidance completing the questionnaire, the ISET was subsequently refined. The second step was to test the validity of the refined ISET by again comparing the outcome of this triage with that of the triage assistant in the emergency department. The first explorative step involved 279 patients and the final validation step 298. During the validation step, sensitivity of the ISET was 94.3% and specificity 76.4%. The results show that the ISET is a sensitive and specific instrument for ophthalmic triage compared with a trained ophthalmic triage assistant.

Wavefront holoscopy: application of digital in-line holography for the inspection of engraved marks in progressive addition lenses

Progressive addition lenses (PALs) are engraved with permanent marks at standardized locations in order to guarantee correct centering and alignment throughout the manufacturing and mounting processes. Out of the production line, engraved marks provide useful information about the PAL as well as act as locator marks to re-ink again the removable marks. Even though those marks should be visible by simple visual inspection with the naked eye, engraving marks are often faint and weak, obscured by scratches, and partially occluded and difficult to recognize on tinted or antireflection-coated lenses. Here, we present an extremely simple optical device (named as wavefront holoscope) for visualization and characterization of permanent marks in PAL based on digital in-line holography. Essentially, a point source of coherent light illuminates the engraved mark placed just before a CCD camera that records a classical Gabor in-line hologram. The recorded hologram is then digitally processed to provide a set of high-contrast images of the engraved marks. Experimental results are presented showing the applicability of the proposed method as a new ophthalmic instrument for visualization and characterization of engraved marks in PALs.

Comparison of reaction response time between hand and foot controlled devices in simulated microsurgical testing.

Purpose. We hypothesized that reaction times (RTs) for a switch release are faster for hand-controlled than for foot-controlled switches for physiological and anatomical reasons (e.g., nerve conduction speed). The risk of accidental trauma could be reduced if the surgeon reacted quicker and therefore improve the surgical outcome. Method. We included 47 medical professionals at USC. Demographics and handedness were recorded. Under a microscope, a simple reaction time test was performed, testing all extremities multiple times in a random order. Additionally, a subjective questionnaire was administered. Results. The mean RTs for hands are 318.24 ms ± 51.13 and feet 328.69 ± 48.70. The comparison of hand versus foot showed significant shorter RTs for the hand (P = 0.025). Partially significant differences between and within the experience level groups could be demonstrated by level of education (LE) and microscopic surgeries/week (MSW) (P = 0.57–0.02). In the subjective questionnaire, 91.5% (n = 43/47) of test subjects prefer to use hand controls. Conclusion. Our data show that the RT for hands is faster than feet. Similarly the subjective questionnaire showed a greater preference for hand actuation. This data suggest a hand-controlled ophthalmic instrument might have distinct advantages; however, clinical correlation is required.

Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror

We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 µm axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical optical components were tested to evaluate handheld OCT ergonomics. An iris camera aided in alignment of the OCT beam through the pupil and a manual fixation light selected the imaging region on the retina. Volumetric and high definition scans were obtained from 5 undilated normal subjects. Volumetric OCT data was acquired by scanning the 2.4 mm diameter 2D MEMS mirror sinusoidally in the fast direction and linearly in the orthogonal slow direction. A second volumetric sinusoidal scan was obtained in the orthogonal direction and the two volumes were processed with a software algorithm to generate a merged motion-corrected volume. Motion-corrected standard 6 x 6 mm(2) and wide field 10 x 10 mm(2) volumetric OCT data were generated using two volumetric scans, each obtained in 1.4 seconds. High definition 10 mm and 6 mm B-scans were obtained by averaging and registering 25 B-scans obtained over the same position in 0.57 seconds. One of the advantages of volumetric OCT data is the generation of en face OCT images with arbitrary cross sectional B-scans registered to fundus features. This technology should enable screening applications to identify early retinal disease, before irreversible vision impairment or loss occurs. Handheld OCT technology also promises to enable applications in a wide range of settings outside of the traditional ophthalmology or optometry clinics including pediatrics, intraoperative, primary care, developing countries, and military medicine.

Corneal Hysteresis With Intraocular Pressure of a Wide Range: A Test on Porcine Eyes

To investigate the relationship between corneal hysteresis (CH) and intraocular pressure (IOP) using porcine eyes in the low to high IOP ranges. In vitro porcine eyes were used to investigate the relationship of CH and IOP. IOP was altered by changing the height of a drip stand within the dynamic range of 60 mm Hg. CH and IOP were measured with the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments, Depew, NY) at different heights. Second-order polynomial regression method was employed to assess the nonlinear correlation of CH and IOP. CH demonstrated an initial plateau stage with low IOP, which then decreased as IOP increased to higher values up to 60 mm Hg. The maximum CH value of approximately 6 to 8 mm Hg was achieved when IOP ranged from 11 to 25 mm Hg. The nonlinear regression lines of Goldmann correlated IOP (IOPg) and CH can be described as CH = − 0.0029 × IOPg2 + 0.1005 × IOPg + 5.2824, R2 = 0.3676, P < .05. CH was relatively constant for lower values of IOP and showed a decreasing relationship at higher values of IOP. This nonlinear relationship provides insight into understanding the viscoelastic nature of CH over a wider range of IOP values. The experimental data on porcine eyes may indicate that IOP should be taken into account when analyzing the deformation response of the cornea to an applied air puff.

Measuring pulse-induced natural relative motions within human ocular tissuein vivousing phase-sensitive optical coherence tomography

We use phase-sensitive optical coherence tomography to measure relative motions within the human eye. From a sequence of tomograms, the phase difference between successive tomograms reveals the local axial motion of the tissue at every location within the image. The pulsation of the retina and of the lamina cribrosa amounts to, at most, a few micrometers per second, while the bulk velocity of the eye, even with the head resting in an ophthalmic instrument, is a few orders of magnitude faster. The bulk velocity changes continuously as the tomograms are acquired, whereas localized motions appear at acquisition times determined by the repeated scan of the tomogram. This difference in timing allows the bulk motion to be separated from any localized motions within a temporal bandwidth below the tomogram frame rate. In the human eye, this reveals a map of relative motions with a precision of a few micrometers per second.

Repeatability of Ocular Response Analyzer Waveform Parameters in Normal Eyes and Eyes After Refractive Surgery

To study the repeatability of the biomechanical waveform parameters measured with the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, NY) device in normal eyes and eyes after refractive surgery. This was a prospective, comparative non-interventional study of a case series. Two hundred eyes of 100 patients were divided into five groups: normal eyes of patients younger than 30 years, normal eyes of patients between 30 and 50 years old, normal eyes of patients older than 50 years, eyes of patients with a history of LASIK, and eyes of patients with a history of photorefractive keratectomy. The repeatability of the 37 waveform parameters in addition to corneal hysteresis (CH), corneal resistance factor (CRF), IOP measurement with Goldmann applanation tonometer (IOPg), and IOP evaluated with the intraclass correlation coefficient (ICC) (IOPcc) were examined. In addition to IOPg, IOPcc, CRF, and CH, five parameters had an ICC greater than 0.6 (substantial agreement): P1area, the area of peak 1 (ICC = 0.823); P2area, the area of peak 2 (ICC = 0.646); h1, the height of peak 1 (ICC= 0.702); P1area1, the area of peak 1 derived from the upper 50% of the applanation peak (ICC = 0.772); and h11, the height of peak1 derived from the upper 50% of the applanation peak 1 (ICC = 0.697). This study shows that not all parameters derived from the corneal deformation waveform signal have the same repeatability. Therefore, analysis of the waveform indices should rely on the more repeatable ones to derive consistent conclusions.

Analysis of Waveform-Derived ORA Parameters in Early Forms of Keratoconus and Normal Corneas

To evaluate the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments, Depew, NY) performance in differentiating grades I and II keratoconus from normal corneas using 41 parameters individually and to assess the effect of analyzing all parameters together. This study compared the mean value of 41 ORA parameters in grades I and II keratoconus with healthy age-matched control eyes. Only eyes with a central corneal thickness between 500 and 600 μm were included. The area under the receiver operating characteristic curve was calculated for each of the 41 parameters independently and for all of the parameters together. This study included 136 eyes with normal corneas and 68 eyes with grades I and II keratoconus. When analyzed individually, four ORA parameters (p1area, p1area1, p2area, and p2area1) had an area under the curve greater than 0.900 for discriminating between both groups. The p2area was the parameter that achieved the largest area under the curve individually (0.931). The area under the curve increased to 0.978 when analyzing all parameters together. Alternative ORA parameters are better for differentiating grades I and II keratoconus from normal corneas than the four parameters originally available for ophthalmologists (corneal hysteresis, Goldmann-correlated intraocular pressure, corneal-compensated intraocular pressure, and corneal resistance factor). Although the ORA did not achieve 100% accuracy, the discrimination between these two groups was optimized by combining all parameters.

Surgical glove perforation among nurses in ophthalmic surgery: A case‐control study

Many of the ophthalmic surgical instruments are extremely fine and sharp. Due to the dim light environment required for ophthalmic surgical procedures, the passing of sharp instruments among surgeons and scrub nurses also poses a risk for glove perforations. A case-control study was performed to determine the number and site of perforations in the surgical gloves used by a group of scrub nurses during ophthalmic surgery. All six nurses working in an eye and refractive surgery centre in Hong Kong participated in the study. A total of 100 (50 pairs) used surgical gloves were collected following 50 ophthalmic surgeries. Fifty pairs of new surgical gloves were also collected. Every collected surgical glove underwent the water leak test. The surgical procedure perforation rate was 8%, and none of the perforations were detected by the scrub nurses. No perforations were found in any unused gloves. The findings indicate that glove perforations for scrub nurses during ophthalmic surgery do occur and mostly go unnoticed. Future studies should continue to explore factors contributing to surgical glove perforation.

Quality Assessment of Ophthalmic Questionnaires

The aim of this article was to systematically review all the available ophthalmic patient-reported outcome (PRO) instruments (questionnaires) that demonstrated interval measurement properties to identify the instruments with the highest psychometric quality for use in different eye diseases and conditions. An extensive literature review was carried out to identify all existing ophthalmic PRO instruments. Instruments were then excluded if they did not have demonstrable interval measurement properties; the remaining instruments were reviewed. The quality of the following psychometric properties was assessed: content development (initial item development process), performance of the response scale, dimensionality (whether the instrument measures a single construct), measurement precision, validity (convergent, concurrent, discriminant, and known groups), reliability (test-retest), targeting (whether the items are appropriate [e.g., difficulty level] for the population), differential item functioning (whether subgroups of people respond differently to an item), and responsiveness. The search identified 48 PRO instruments that demonstrated interval measurement properties, and these were relevant to nine applications: glaucoma, dry eye, refractive errors, cataract, amblyopia and strabismus, macular diseases, adult low vision, children low vision, and others. These instruments were evaluated against the psychometric property quality criteria and were rated for quality based on the number of criteria met. This review provides a descriptive catalog of ophthalmic PRO instruments to inform researchers and clinicians on the choice of the highest-quality PRO instrument suitable for their purpose.