The relationship between optical coherence tomography patterns, angiographic parameters and visual acuity in age-related macular degeneration

Can objective parameters in optical coherence tomography be useful markers in the treatment and follow-up of type 1 and type 2 macular neovascularizations related to neovascular age-related macular degeneration?

PURPOSE

The aim of this study was to compare the responses of type 1 and type 2 macular neovascularizations (MNV) caused by neovascular type age-related macular degeneration (n-AMD) to intravitreal anti-vascular endothelial growth factor (VEGF) treatments using quantitative parameters determined by optical coherence tomography (OCT). Additionally, it was also intended to assess the connections between these quantitative parameters and changes in best-corrected visual acuity (BCVA) and the number of intravitreal anti-VEGF injections required within a year.

MATERIALS AND METHODS

In our retrospective and observational study, the data of 90 eyes of 90 patients diagnosed with n-AMD and treated with intravitreal anti-VEGF with the "Pro re nata" method were evaluated. Subtypes of existing MNVs were distinguished with previously taken optical coherence tomography angiography (OCTA) images. In spectral domain OCT examinations, central macular thickness (CMT) and central macular volume (CMV) values were recorded at baseline and 12th month. The number of intravitreal anti-VEGF injections during the 12 month follow-up period was also recorded for each patient. Obtained data were compared between MNV types.

RESULTS

Of the n-AMD cases examined in the study, 56.66% had type 1 MNV and 43.34% had type 2 MNV. The mean baseline BCVA logMAR values in eyes with type 2 MNV (1.15 ± 0.43) were higher than those observed in eyes with type 1 MNV (0.76 ± 0.42) (p = 0.001). Similarly, mean baseline CMT and CMV values in eyes with type 2 MNV were higher than those observed in eyes with type 1 MNV (respectively 424.89 ± 49.46 μm vs. 341.39 ± 37.06 μm; 9.17 ± 0.89 μm3 vs. 8.49 ± 0.53 μm3; p < 0.05). After 12 months of treatment, logMAR values of BCVA (0.86 ± 0.42) in subjects with type 2 MNV were higher than those in subjects with type 1 MNV (0.57 ± 0.37) (p = 0.001). Mean CMT and CMV values at 12th month in subjects with type 2 MNV (379.11 ± 46.36 μm and 8.66 ± 0.79 μm3, respectively) were observed to be higher than those with type 1 MNV (296.95 ± 33.96 μm and 8.01 ± 0.52 mm3, respectively) (p < 0.05). In type 2 MNVs, positive correlations were observed between both baseline and 12th month BCVA logMAR values and baseline CMV (p < 0.05). Similarly, in type 2 MNVs, a positive correlation was observed between 12th month BCVA logMAR values and 12th month CMV (p < 0.05). The total number of intravitreal anti-VEGF injections at 12 months was similar in both groups (p = 0.851).

CONCLUSION

In this study, in which we performed a subtype analysis of MNV cases, we observed that the visual function was worse at the beginning and the end of the 12th month, and the CMT and CMV values were higher in the type 2 MNV group compared to the type 1 MNV cases. In addition, we found significant correlations between BCVA logMAR values and CMV values in type 2 MNV cases. In the follow-up of these cases, CMT, which is a more widely used quantitative method, and CMV, which is a newer OCT measurement parameter, may be more useful in patient follow-up and evaluation of treatment efficacy, especially for type 2 MNV cases.

Association between retinal thickness variation and visual acuity change in neovascular age-related macular degeneration

BACKGROUND

To assess the association between variation in retinal central subfield thickness (CSFT) with best-corrected visual acuity (BCVA) change in patients receiving vascular endothelial growth factor (VEGF) inhibitor therapy for neovascular age-related macular degeneration (nAMD).

METHODS

CSFT measurements were obtained from 141 eyes (total 1300 scans). SD of CSFT was calculated. The eyes were categorised into CSFT variation tertiles. Multiple linear regression was used to examine the association between the CSFT tertiles and BCVA change at 12 mo, adjusting for differences in baseline demographic and clinical characteristics.

RESULTS

At 12 mo, the mean BCVA of the high CSFT variation group (50.6 letters) was significantly lower than the low and moderate CSFT variation groups (57.5 and 59.8 letters, respectively), P = .02. The adjusted mean BCVA gains were +1.7, +7.2, and +7.8 letters in the high, moderate and low CSFT variation groups, respectively (P = .03).

CONCLUSIONS

A greater variation in retinal thickness during VEGF inhibitor therapy for nAMD is associated with a less favourable visual outcome. CSFT stability is useful in prognosticating visual outcomes in VEGF inhibitor therapy for nAMD.

Relationship Between Visual Acuity and Retinal Thickness During Anti-Vascular Endothelial Growth Factor Therapy for Retinal Diseases

PURPOSE

To investigate the relationship between best-corrected visual acuity (BCVA) and central retinal thickness (CRT) in eyes receiving ranibizumab for 3 common retinal diseases.

DESIGN

Retrospective analysis of clinical trial data.

METHODS

Early Treatment Diabetic Retinopathy Study BCVA and spectral-domain optical coherence tomography-measured CRT of 387 eyes of 345 patients enrolled in 6 prospective clinical trials for management of neovascular age-related macular degeneration (AMD), diabetic macular edema (DME), and retinal vein occlusion (RVO) were evaluated by Pearson correlation and linear regression.

RESULTS

At baseline, there was a small correlation between BCVA and CRT in pooled AMD trial data (r = -0.24). A medium correlation was identified in pooled DME trial data (r = -0.42). No correlation was found in pooled RVO trial data. At month 12, no correlation was found between changes from baseline in BCVA and CRT in pooled AMD trial data. Medium correlations were identified in both pooled DME (r = -0.45) and pooled RVO (r = -0.35) trial data at month 12. Changes in BCVA and CRT associated with edema recurrence upon transition from monthly to pro re nata (PRN) dosing were correlated in AMD (r = -0.27) and RVO (r = -0.72) trials, but not in DME trial data.

CONCLUSION

DME demonstrated a convincing relationship between BCVA and CRT. Correlations appear to be more complex in AMD and RVO. At the inflection point between monthly and PRN dosing, when recurrence of edema is anticipated in many patients, CRT appears strongly correlated with loss of BCVA in RVO.

Cross-sectional pupillographic evaluation of relative afferent pupillary defect in age-related macular degeneration

To evaluate, using pupillography, the difference between eyes affected by age-related macular degeneration and their contralateral normal eyes with regard to the mean relative afferent pupillary defect (RAPD) score. Also, to ascertain any correlations between this difference in RAPD score and differences in visual acuity or age-related macular degeneration (AMD) dimensions. Measurements were made using the RAPDx pupillographer (Konan Medical, Nishinomiya, Japan), which analyzes pupil response to light stimulation. Both best corrected visual acuity (converted to logMAR) and greatest linear dimension (GLD; calculated on the basis of fluorescence angiography images) were measured. The correlations between RAPD difference and logMAR difference, and GLD difference were then analyzed. The study included 32 patients (18 men, 14 women; mean age = 74.8 ± 9.7 years) who had AMD in 1 eye and a normal fundus in the contralateral eye. Mean resting pupil diameter, mean latency onset of constriction, mean velocity of constriction, and recovery were not significantly different in AMD eyes compared with normal eyes. The mean amplitude of constriction was smaller (P = 0.028), and the mean latency of maximum constriction was shorter (P = 0.0013) in AMD eyes than in normal eyes. Regarding RAPD scores, there was a significant correlation between visual acuity difference and RAPD score differences of both amplitude (P < 0.001, r = 0.53) and latency (P = 0.034, r = 0.33). GLD difference was also significantly correlated with differences in both amplitude (P = 0.021, r = 0.36) and latency (P = 0.033, r = 0.33) scores. RAPD outcomes were correlated with visual acuity and AMD dimension. Automated pupillography may be a useful tool in monitoring the progression of AMD and assessing changes in retinal function that result from novel interventions.

Patients' visual experience during phacoemulsification cataract surgery and associated fear

Background

Data from several published studies indicate that patients undergoing phacoemulsification cataract surgery can experience a variety of visual sensations which can result in fear. This phenomenon has not been studied in Pakistan to-date. We examined the visual experience and its associated fear among patients undergoing phacoemulsification cataract surgery under topical anaesthesia.

Methods

This cross-sectional study was carried out in Aga Khan University Hospital, a tertiary care hospital, in Karachi, Pakistan from August 2010 to July 2011. Adults >18 years of age scheduled to undergo cataract surgery (phacoemulsification with intraocular lens implantation) under topical anaesthesia by a single surgeon were included. A structured questionnaire was used to collect data on socio-demographics, intraoperative visual experiences and subsequent reaction to these sensations. Participants were asked if they experienced visual sensations such as colours, shapes and movements during surgery. Moreover, they were asked if they developed fear due to these sensations.

Results

Fifty three patients (mean age: 60.4 ± 12.4 years) were enrolled. Thirty (56.6%) of them were men and 23 (43.4%) were women. All of them reported having experienced visual sensations during surgery, the most common being light perception (100%), different colours (77.4%), movements of instruments or surgeon’s hands (37.7%) and different shapes (7.5%) such as circles, clouds and patches. The most common colours perceived included white (46.2%), blue (35.8%), red (30.2%) and yellow (30.2%). One out of every four (26.4%) participants reported having developed fear due to these visual sensations. Only 4 (7.5%) reported having received preoperative counselling regarding such sensations.

Conclusion

Patients in our study experienced a variety of visual sensations during cataract surgery under topical anaesthesia. The prevalence of frightening visual sensations is higher than that reported in all previous published studies on the subject and needs to be addressed through targeted interventions.