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Effect of cataract on frequency doubling perimetry versus standard automated perimetry in normal subjects

Thesis

Last updated: 06 Feb 2023

Subjects

-

Tags

Ophthalmology

Advisors

Essam-El-Din, Hamdi M., El-Sanabari, Zainab, Nagati, Muhammad W.

Authors

Abdel-Hamid, Rehab Mahmoud

Accessioned

2017-07-12 06:39:44

Available

2017-07-12 06:39:44

type

M.Sc. Thesis

Abstract

Purpose: The aim of this study is to compare the extent; depth of pattern of visual field defects related to cataract in FDP (frequency doubling perimetry) versus SAP (standard automated perimetry) in non glaucomatous subjects to detect the least affected automated perimetry method.Methods: Twenty patients(20 eyes) who underwent cataract surgery (Phacoemulsification OR Extra capsular cataract extraction , 10 patient have N2-N5 nuclear cataract and the other 10 having posterior subcapsular cataract grading P2-P4 according to lens opacities classification system version III (LOCS III ) were included in the study.Study design: prospective non controlled study. FDT; utilizes a vertical sine wave grating of low spatial frequency (0.25 c/deg) that undergoes counterphase flickering at a high temporal frequency (25 Hz). These test used in the study was The C-20 presentation pattern tests the central 20º with 17 stimulus locations, made up of four 10º targets per quadrant and one circular 5º central one was used in this study .SAP ;size III test target, 200-msec stimulus duration, and 31.5-apostilb (asb; 10 candelas [cd]/m2) background illumination.using the SITA Standard program 24-2(54 locations and 30◦ at the nasal periphery).Results: Ten eyes had nuclear cataract with different grading as the values of MD and PSD in both tests SAP and FDP before and after extraction of cataract. The retinal sensitivity was affected by cataract in both tests (SAP and FDP). the range of MD was from (-4.66 mild suppression) to (-32.12 severe suppression) with SAP; and the range was from (-0.88 within normal) to (-17.8 severe suppression) in FDP.Ten cases had posterior subcapsular cataract with different grading as the values of MD and PSD in both tests SAP and FDP before and after extraction of cataract. As shown; the retinal sensitivity was affected by cataract in both tests (SAP and FDP).the range of MD was from (-4.18 mild suppression) to (-15.81 severe suppression) with SAP; and the range was from (-3.18 mild suppression) to (-18.63 severe suppression) in FDP. Impact of both nuclear (N2,N3) and PSC (P2:P4) on visual field tests SAP and FDP in the form of generalized reduction of retinal sensitivity with worsening of both MD and PSD which markedly improved after cataract extraction. Peripheral scattered scotomata or contraction were detected in cases having nuclear cataract grade III. Central and paracentral scotomata; nasal stepping were observed more in cases with dense PSC (III-IV). MD is found to be significantly correlated with visual acuity after cataract extraction and both types of cataract affect FDP more, that could be explained by the effect of cataract on contrast sensitivity.Conclusion: Global indices of FDT should be used with caution in patients with cataract therefore biomicroscopy examination of the anterior segment is thus essential at excluding VF loss strictly due to cataract.

Issued

1 Jan 2012

DOI

http://dx.doi.org/10.21473/iknito-space/34595

Details

Type

Thesis

Created At

28 Jan 2023