Quantifying microstructural changes in retinitis pigmentosa using spectral domain – optical coherence tomography

Abstract

Background Most patients of established retinitis pigmentosa (RP) have subnormal peripheral vision and heavily rely on central vision for their daily activities. Central visual acuity is dependent on photoreceptor survival at the macula. Identification of structural changes that precede visual loss is essential. The aim of this study was to correlate the Spectral Domain-Optical Coherence Tomography (SD-OCT) characteristics with visual acuity in patients with typical RP. Methods This was a retrospective, observational case series of 224 eyes of 113 RP patients conducted a tertiary eye care center. SD-OCT imaging was done for all eyes. Central retinal thickness (CRT), photoreceptor outer segment length (PROS), foveal outer segment pigment epithelial thickness (FOSPET) and ellipsoid zone (EZ) extent were measured. A new variable, FOSPET-PROS ratio (FPR), obtained by dividing FOSPET by PROS is defined and correlated to corrected distance visual acuity (CDVA) in logMAR using linear regression. Results Out of 113 patients, 71 were males and 42 females. Mean age of the patients was 35.4 ± 15.1 years. Mean CDVA was 0.33 ± 0.25 logMAR with no difference between the genders. Mean CRT (218.74 ± 83.5 μm) and FPR (1.63 ± 0.22) significantly correlated to CDVA with a correlation coefficient of r = − 0.139 ( p = 0.048) and r = 0.842 ( p = 0.0001), respectively. FOSPET (mean = 71.15 ± 13.8 μm) and PROS (mean = 44.85 ± 12.5 μm) did not show a significant correlation to CDVA, independent of FPR. Conclusions Retinal microstructural changes on SD-OCT, especially the FPR, can be used as a surrogate marker to monitor disease progression in the central retina in degenerative diseases like RP.

Management of Retinitis Pigmentosa via Platelet Rich Plasma or Combination with Electromagnetic Stimulation: Retrospective Analysis of One-year Results

“…The ciliopathy gene mutations have threefold faster progression than non-ciliopathy mutations [23]. Retinitis pigmentosa progresses with an average of 10% annual photoreceptor loss when AD, AR, X-linked, and mitochondrial inheritance patterns are collectively evaluated [6,24,25]. In our study, the annual photoreceptor loss rate was found to be 9.3% on average in the RP group without interventional procedures (Group 3, natural course) similar to the literature.…”

“…Ellipsoid zone (EZ) is an OCT image of the inner and outer segments of photoreceptor cells. Loss of EZ is the gold standard in the diagnosis and follow-up of RP [6,7]. Visual field (VF) monitoring and electroretinography (ERG) are indirect signs of EZ loss and correlated with EZ width (EZW) [6].…”

“…Loss of EZ is the gold standard in the diagnosis and follow-up of RP [6,7]. Visual field (VF) monitoring and electroretinography (ERG) are indirect signs of EZ loss and correlated with EZ width (EZW) [6]. Mutations in PR or RPE disrupt the synthesis of some vital peptides and growth factors for photoreceptors [1].…”

Optical coherence tomography biomarkers of photoreceptor degeneration in retinitis pigmentosa

“…[18] Except for ONLT and the transverse ELM length, we found that all the other biomarkers had a signi cant correlation with BCVA. In the literature, there were several reports of the association of OCT biomarkers with visual acuity, such as the presence of EZ at fovea [19], length of the IZ, [17] thickness of outer segments and full thickness of photoreceptor, [22][23][24] and optical intensity of EZ. [10] In our work, the mean IST within the central 1-mm-wide retinal area had the greatest correlation with BCVA among these metrics.…”

Optical coherence tomography in pediatric patients: a clinical review

“…One study found the ratio between foveal outer segment pigment epithelial thickness and photoreceptor outer segment length, measured with OCT, could be used as a surrogate to monitor central retina disease in RP, which is useful to predict visual outcomes in these patients. 26 OCT is also used to monitor more obvious structural changes in the retina such as outer nuclear layer (ONL) thinning and thinning of the outer segment, with no associated changes in the inner nuclear layer or ganglion cell layer of the inner retina. 22,27,28 In addition, OCT is used to detect and monitor cystoid macular edema (CME) associated with RP, which can be treated with carbonic anhydrase eye drops with variable outcomes (see Figure 2 for example).…”