The impact of keratoconus treatment with the Athens Protocol (partial topography-guided photorefractive keratectomy combined with higher-fluence corneal collagen cross-linking) on quality of life: a long-term study

Combined topography-guided photorefractive keratectomy and corneal collagen crosslinking

PURPOSE

This study aimed to report the long-term results of combined topography-guided photorefractive keratectomy (PRK) and accelerated corneal collagen cross-linking (CXL) for keratoconus using the Zeiss refractive coordinated system.

METHODS

A prospective interventional study was conducted in a tertiary eye care hospital in South India. Patients with mild-to-moderate progressive keratoconus and corneal pachymetry greater than 450 µm were included. They underwent customized topography-guided PRK followed by CXL. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and keratometry readings and complications were evaluated at 1, 3, 6, 12, and 24 months postoperatively.

RESULTS

Thirty patients (30 eyes) were included in the study. All study parameters showed a statistically significant improvement postoperatively over baseline values. At 24 months, the mean UDVA improved from 0.8 ± 0.180 logarithm of the minimum angle of resolution (logMAR) to 0.38 ± 0.118 logMAR ( P -value <0.001) and CDVA improved from 0.467 ± 0.142 logMAR to 0.227 ± 0.078 logMAR ( P -value <0.001). The mean flat, steep, and maximum keratometry values were significantly reduced by 2.133, 3, and 4.54 diopters, respectively, at the last follow-up examination ( P -value <0.001).

CONCLUSION

The combined topography-guided PRK and accelerated CXL procedure seem to be a promising treatment alternative for early keratoconus. This is the first such study on the Zeiss refractive coordinated system. However, further studies with a larger study population and longer follow-up periods are required to draw final conclusions about the benefits of this procedure in keratoconus.

[Effect of keratoplasty on the quality of life of keratoconus patients]

Corneal deformations caused by keratoconus produce high levels of optical aberration (OA). Despite appropriate optical correction, these alter the quality of vision and diminish the patient's quality of life, especially since the affected population is predominantly young and of working age. When thinning is too severe or corneal transparency too impaired, a corneal transplant may be considered. In this study, we compare the quality of life of patients with keratoconus in the early (stages 1 and 2) or advanced (stages 3 and 4) stages of the Krumeich classification, as well as patients who have had keratoconus treated by keratoplasty. Quality of life was assessed using the NEI-VFQ 25 questionnaire, the most widely used for keratoconus. An aberrometric examination (OQAS®; HD Analyser, Visiometrics, Terrassa, Spain) was also performed to assess patients' quality of vision. Our results show that keratoplasty provides an improvement in quality of life compared with advanced-stage keratoconus in the areas of distance (p=0.0083) and near vision (p=0.029) activities. This improvement also applies to Best-Corrected Visual Acuity (BCVA) (p=0.032) and transparency (OSI) (p=0.049). Our study shows that keratoplasty improves corneal transparency, and it is interesting to note that it improves patients' quality of life over the long term.

Evaluation of the test-retest and inter-mode comparability of the Impact of Vision Impairment questionnaire in people with chronic eye diseases

PURPOSE

The main objective of this study is to assess the test-retest and inter-administration mode reliability of the Impact of Vision Impairment profile (IVI), a common patient-reported outcome measure (PROM) for people with chronic eye diseases.

METHODS

The IVI was administered to adult patients with stable, chronic eye diseases two to four times per participant (average intervals between administrations 12 to 20 days; maximum two phone interviews, paper administration, electronic administration) by two trained interviewers. Rasch models were fit to the data. Intra-class correlation coefficients (ICCs), mean differences and Cronbach's alpha between test-retest administrations (two phone interviews) and inter-mode comparisons were calculated.

RESULTS

Two hundred-sixteen patients (mean age 67 ± 12 years, 40% male) were included in the study. The IVI met all psychometric requirements of the Rasch model, and the division into the domains of functional items (IVI_F) and emotional items (IVI_E) corresponded to the German validation study. ICCs (all for IVI_F and IVI_E, respectively) for the retest administrations were 0.938 and 0.912, and 0.853 and 0.893 for inter-mode comparisons phone/paper, 0.939 and 0.930 for phone/electronic, and 0.937 and 0.920 for paper/electronic (all p < 0.01). Mean differences (all for IVI_F and IVI_E, respectively) for the retest administrations were 2.8% and 0.7% and ranged from 2.0% to 6.2% and from 0.4 % to 4.9% between administration modes. Cronbach's alpha ranged from 0.886 to 0.944 for retest and inter-mode comparisons.

CONCLUSION

Due to the high test-retest reliability and the almost equally high comparability of different modes of administration of the IVI, the study endorses its use as a robust PROM to capture vision-related quality of life. Our results further support the use of the IVI as an endpoint in clinical trials and may simplify implementing it in both clinical trials or real-world evidence generation by offering multiple administration modes with high reliability.

Combined Photorefractive Keratectomy and Corneal Cross-Linking for Keratoconus and Ectasia: The Athens Protocol

ABSTRACT

Customized photorefractive keratectomy with minimal tissue ablation combined with corneal cross-linking seems to be a long-term safe and effective strategy for anatomical and visual management of keratoconus, postsurgical ectasia, and other ectasia management. Multiple published studies, many with long-term follow-up, have supported the Athens Protocol and its various forms as a means to manage corneal ectatic disorders, which not only stabilize corneal shapes but also improve functional vision.

Impact of Cross-Linking Procedure on Perioperative Quality of Life in Keratoconus Patients

BACKGROUND

To evaluate the effect of crosslinking (CXL) with riboflavin for keratoconus (KC) therapy on quality of life (QoL): comparison of keratoconus patients with and without treatment.

METHODS

Prospective monocentric study. We recruited patients with progressive KC and with stable disease. Patients with progressive disease received cross-linking treatment; patients with stable disease were monitored. We compared QoL in both groups over 6 months and detected the influence of cross-linking treatment on QoL. QoL was assessed by NEI-VFQ-25, EQ-5D 5L, and EQ-Visual analog scale (VAS). In the evaluation of the Nei VFQ, the subgroups LFVFS and LFSES were calculated.

RESULTS

We enrolled 31 eyes of 31 patients in the intervention group and 37 eyes of 37 patients in the control group. Medians with standard deviations (SD) were calculated. All QoL-tests showed equal scores at baseline in both groups. At V2, one day after the treatment, EQ-VAS (56.4), LFVFS (57.4), and EQ5D5L (0.59) were significantly reduced. At V3 (one week after treatment), all results returned to baseline level. LFSES was not affected by the treatment. It remained stable (V2 85.4, V3 84.3). Comparing the baseline scores with the follow-up scores at month 6, we found a significant increase in QoL in all tests in the intervention group. Otherwise, the quality of life in the control group did not change over time.

CONCLUSIONS

Cross-linking led only to a short-term reduction in QoL. Although the treatment is painful for a few days, no effect on general quality of life LVSES has been demonstrated. QoL already returned to baseline after one week and the patients were not limited anymore.

Quality of life and tomography indices in patients with keratoconus

OBJECTIVE

Keratoconus is a corneal ectasia that leads to thinning and steepening of the corneal surface. We aimed to assess the relationship between quality of life and corneal tomography indices, irrespective of visual acuity.

METHODS

This was a cross-sectional study using a translated and validated Keratoconus Outcomes Research Questionnaire (KORQ) in Arabic language. We screened patients with keratoconus using the Belin/Ambrósio D-Index. We included the best-seeing eye in each patient with keratoconus, with a best corrected visual acuity better than 0.5. We collected variables including KORQ scores, flattest meridian keratometry, steepest meridian keratometry, mean keratometry front, maximum simulated keratometry, astigmatism front, Q value front, and thickness at the thinnest location. We performed linear regression analysis to identify predictors of the visual function score and symptom score.

RESULTS

Sixty-nine patients were included in this study, 43 (62.3%) male and 26 (37.7%) female patients, with a mean age 34.0 ± 11.50 years. The only predictor for visual function score was sex (β = 11.64, 95% confidence interval: 3.50-19.78). None of the topographic indices were related to quality of life.

CONCLUSION

In this study, quality of life in patients with keratoconus was not related to specific tomography indices and might be related to visual acuity itself.

Impact of corneal collagen cross-linking on vision-related quality of life measured with the keratoconus outcomes research questionnaire (KORQ) in patients with keratoconus

PURPOSE

To assess the impact of corneal collagen cross-linking on self-reported vision-related quality of life (VR-QoL) in keratoconus patients by means of the Keratoconus Outcomes Research Questionnaire (KORQ), a new disease-specific patient reported outcomes measures (PROMs) tool.

METHODS

Patients with progressive keratoconus undergoing corneal collagen cross-linking were consecutively enrolled. Patients completed the KORQ before and after the treatment, at 1, 3 and 6 months. Data were collected regarding the visual acuity and the topographic, aberrometric and pachymetric parameters of both eyes. Patients were also asked to quantify their eye rubbing behavior on a Visual Analogue Scale (VAS) from 0 to 10, before and 6 months after treatment. The KORQ scores were associated with the visual acuity, topographic, aberrometric and pachymetric data by means of the Spearman correlation coefficient.

RESULTS

The Activity Limitation (AL) subscale score was higher after surgery. Preoperatively, negative correlations were observed between the KORQ AL score and Best Corrected Visual Acuity (logMAR), maximum keratometry, flattest keratometry, steepest keratometry, symmetry index front and higher order aberrations (HOA) of the treatment eye. Postoperatively, we observed a shift toward the fellow eye, with stronger correlation of the KORQ scores with the fellow eye parameters. The Symptoms subscale score correlated with the aberrometric parameters of both eyes at various time points. Statistically significant correlations were observed between the change in KORQ scores and the change in aberrometric parameters. A statistically significant reduction in the eye rubbing behavior was detected (p < 0,0001).

CONCLUSIONS

These results suggest that the corneal cross-linking treatment is effective both in improving the subjective perception of the disease by the patient and in stabilizing the objective indicators of disease progression. Keratometric, aberrometric and visual acuity values showed a significant impact on self-reported VR-QoL. Corneal cross-linking, by halting the worsening of these parameters, may bear a beneficial effect on VR-QoL.

Decentered Individualized Sphero-Cylindrical (DISC) Ablation and Corneal Crosslinking in Patient with Progressive Keratoconus

Aim

To report a new method with which we have treated a 29-year-old patient with keratoconus and progressive bilateral visual loss during the past few years.

Methods

The patient underwent inferotemporal decentered individualized sphero-cylindrical (DISC) ablation and crosslinking (CXL) of the left eye. After administration of topical anesthetic, the patient was subjected to phototherapeutic keratectomy (PTK) laser ablation of the central 7.0 mm optical zone with 50 μm depth of epithelial ablation. To avoid the possible outcome of corneal haze, 0.02% mitomycin C (MMC) was applied to the stromal surface for 40 seconds. Riboflavin 0.1% solution was then administered topically every 2 minutes for a 30-minute period followed by 5 cycles of corneal crosslinking, radiating with UV-A at 3 mW/cm², for a duration of 5 minutes.

Results

17 months postoperative, there was an impressive improvement in uncorrected distance visual acuity, and the cornea became more regular. Results of Fourier's analysis imply a drop of irregularity (-28.6% two months and –63% seventeen months postoperative), Zernike analysis revealed a decrease of higher order aberrations (spheric and comatic aberrations), and corneal index values in the 8 mm zone (IHD, ISV, and IVA) became lower, compared to the preoperative values.

Conclusion

It is possible to obtain better outcome of visual function with DISC ablation through an individual approach compared to CXL solely. This approach might be a promising strategy in retrieving impaired vision in patients suffering from keratoconus.

Short- and long-term safety and efficacy of corneal collagen cross-linking in progressive keratoconus: A systematic review and meta-analysis of randomized controlled trials

PURPOSE

The purpose of the study is to evaluate the safety and outcomes of corneal collagen cross-linking (CXL) and different CXL protocols in progressive keratoconus (PK) population at short and long-term.

MATERIALS AND METHODS

A systematic review and meta-analysis was conducted. A total of eight literature databases were searched (up to February 15, 2022). Randomized controlled trials (RCTs) comparing CXL versus placebo/control or comparing different CXL protocols in the PK population were included. The primary objective was assessment of outcomes of CXL versus placebo and comparison of different CXL protocols in terms of maximum keratometry (Kmax) or Kmax change from baseline (Δ), spherical equivalent, best corrected visual acuity (BCVA), and central corneal thickness (CCT) in both at short term (6 months) and long term (1^st, 2^nd, and 3^rd year or more). The secondary objective was comparative evaluation of safety. For the meta-analysis, the RevMan5.3 software was used.

RESULTS

A total of 48 RCTs were included. Compared to control, CXL was associated with improvement in Δ Kmax at 1 year (4 RCTs, mean difference [MD], -1.78 [-2.71, -0.86], P = 0.0002) and 2 and 3 years (1 RCT); ΔBCVA at 1 year (7 RCTs, -0.10 [-0.14, -0.06], P < 0.00001); and Δ CCT at 1 year (2 RCTs) and 3 years (1 RCT). Compared to conventional CXL (C-CXL), deterioration in Δ Kmax, ΔBCVA and endothelial cell density was seen at long term in the transepithelial CXL (TE-CXL, chemical enhancer). Up to 2 years, there was no difference between TE-CXL using iontophoresis (T-ionto) and C-CXL. At 2 and 4 years, C-CXL performed better compared to accelerated CXL (A-CXL) in terms of improving Kmax. Although CCT was higher in the A-CXL arm at 2 years, there was no difference at 4 years. While exploring heterogeneity among studies, selection of control eye (fellow eye of the same patient vs. eye of different patient) and baseline difference in Kmax were important sources of heterogeneity.

CONCLUSION

CXL outperforms placebo/control in terms of enhancing Kmax and CCT, as well as slowing disease progression over time (till 3 years). T-ionto protocol, on the other hand, performed similarly to C-CXL protocol up to 2 years.

The Italian version of the Keratoconus Outcomes Research Questionnaire (KORQ): Translation and validation of psychometric properties

PURPOSE

To develop and validate the Italian version of the Keratoconus Outcomes Research Questionnaire (KORQ).

METHODS

Cross-sectional validation study. Keratoconus patients with routine appointments at the outpatient clinic were consecutively enrolled in conjunction with a sample of non-keratoconus controls for comparison. The Italian translation from the original English version of the KORQ was administered to the patients together with the Italian version of the 25-item version of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25). The reliability and validity of the Italian KORQ were assessed using standardized internationally accepted methods for cultural adaptation and validation of health-related quality of life measures.

RESULTS

One hundred patients were deemed eligible and completed the questionnaires. The Cronbach's alpha coefficient for internal consistency ranged from 0.71 to 0.956 across the subscales. Spearman correlation coefficient and intraclass correlation coefficient of 0.98 showed excellent test-retest reliability. The control group had better scores on every subscale. Statistically significant correlations were found between the KORQ and analogous domain of the NEI VFQ-25 and with disease severity indicators, such as visual acuity, maximum keratometry, and steepest keratometry, thus demonstrating good construct and concurrent validity.

CONCLUSION

The Italian version of the KORQ exhibited excellent internal consistency, test-retest reliability, validity, discriminatory power, and psychometric properties comparable with those of the original English version, and thus may be adopted as a powerful vision-targeted quality of life assessment tool for Italian keratoconus patients.

Quality of life in stable and progressive 'early-stage' keratoconus patients

PURPOSE

To analyse the vision-related quality of life (vr-QoL) in stable and progressive keratoconus (KC) patients with a still good visual acuity.

METHODS

Combined prospective/cross-sectional study design. The Refractive Status and Vision Profile (RSVP) and the National Eye Institute Visual Functioning - 25 (NEI-25) questionnaire were used in 16 emmetropic, 32 myopic and 56 KC patients, whereby KC patients with a stable (n = 26) and patients with a progressive stage (n = 30) and some of them before and after corneal cross-linking (CXL; n = 10) were included. All patients had a DCVA in at least one eye of ≥0.7 (decimal chart).

RESULTS

The analyses revealed a minor decline of the vr-QoL from emmetropes to myopes to early KC patients with a stable disease. Nonetheless, sociological subscales (i.e. 'social functioning', 'role difficulties' and 'dependency') did not display statistically significant differences comparing these groups. In progressive KC, we could demonstrate a statistically significant decline also of these sociological subscales, which did not improve after CXL.

CONCLUSION

Due to a still high and almost unaffected vr-QoL in early KC patients and the distinct decline after progression without rehabilitation after CXL, a reconsideration of current strategies to perform CXL only after a progression is diagnosed should be re-evaluated.

[Excimer laser in keratoconus management]

Visual rehabilitation in keratoconus is a challenge, notably because of the significant irregular astigmatism and optical aberrations that it induces. Many surgical techniques have been developed in addition to, or in the case of failure of, spectacles and rigid gas permeable contact lenses: intracorneal ring segments, intraocular lenses, excimer laser and, as a last resort, keratoplasty. Excimer laser photoablates the cornea, allowing remodeling of its surface. There are various treatment modes (wavefront-optimized, wavefront-guided and topography-guided), allowing performance of a customized treatment if needed. Its use in keratoconus has been described since the 2000s, alone or in combination with other procedures. For example, the combination of photoablation and corneal cross linking, a technique that increases corneal rigidity and in so doing can slow or even stop the progression of keratoconus, proved its efficacy and safety in many studies, and various protocols have been described. A triple procedure, including intracorneal ring segments, excimer laser and cross linking, has also given some very promising results in progressive keratoconus, providing a significative improvement in visual acuity and topographic data. The combination of excimer laser and intraocular lenses remains a poorly explored lead that might provide some satisfactory results. The objective of this review is to summarize the recent data on excimer laser in keratoconus management.

Translation and validation of the "Questionnaire for research on keratoconus results" (KORQ) in the Colombian population

OBJECTIVE

It is proposed to carry out a process of translation and adaptation of the "Questionnaire for Research on Keratoconus Results" (KORQ) into Spanish and its validation in a Spanish-speaking population, such as Colombia. This is intended to provide a tool for measuring and monitoring the commitment to quality of life of patients with this corneal ectasia.

MATERIAL AND METHODS

A prospective analytical study was carried out, in which 200 subjects diagnosed with keratoconus completed a translated version of the KORQ questionnaire. The internal validity of the questionnaire was evaluated using Cronbach's Alpha, while its construction was evaluated by an Exploratory Factor Analysis, including a Parallel Horn Analysis for the selection of the number of underlying factors. Subsequently, 50 patients were re-selected to complete the questionnaire one week later. The repeatability of the questionnaire was measured by the Spearman test.

RESULTS

The KORQ questionnaire in its Spanish version showed some internal validity in both sections. Both sections of the questionnaire showed an essentially unidimensional behaviour. The test-retest repeatability of the test was excellent (Spearman rho> 0.95).

CONCLUSIONS

The translated version of the KORQ is valid in Colombian population.